Advances in Structural Engineering and Rehabilitation: Select Proceedings of TRACE 2018 [1st ed.] 978-981-13-7614-6;978-981-13-7615-3

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Advances in Structural Engineering and Rehabilitation: Select Proceedings of TRACE 2018 [1st ed.]
 978-981-13-7614-6;978-981-13-7615-3

Table of contents :
Front Matter ....Pages i-xii
Experimental and Numerical Study to Improve Lateral Load Resistance of Masonry Stack (A. K. Shukla, Saurav, P. R. Maiti)....Pages 1-13
Experimental Study of Confined Brick Masonry Building (A. K. Shukla, P. R. Maiti)....Pages 15-40
A Stochastic Investigation of Effect of Temperature on Natural Frequencies of Functionally Graded Plates (P. K. Karsh, T. Mukhopadhyay, S. Dey)....Pages 41-53
Retrofitting of a Multistoried Building with Earthquake-Resistance Design (J. Bhattacharjee, Harshul Mehta, Shiv Dutt Singh Thakur, Aditya Jain)....Pages 55-62
Biological Methods to Achieve Self-healing in Concrete (Sunita Bansal, Raj Kumar Tamang, Prince Bansal, Pratik Bhurtel)....Pages 63-71
Finite Element Analysis of Profiled Deck Composite Slab Using ANSYS (Aniket A. Shirgaonkar, Yogesh D. Patil, Hemant S. Patil)....Pages 73-82
A Brief Review of Structural Aspects of IS 16700:2017 (Vikalp Gupta, Sanket Rawat, Ravi Kant Mittal, G. Muthukumar)....Pages 83-91
Are FRPs the Way Forward for the Blast Retrofitting of Reinforced Concrete Structures? (Aashish Kumar Jha, Abhiroop Goswami, Satadru Das Adhikary)....Pages 93-104
Analytical Study of Triple Friction Pendulum Under a Different Hazard Level of Earthquakes (Ankit Sodha, Sandeep Vasanwala, Devesh Soni, Shailendra Kumar, Kanan Thakkar)....Pages 105-111
Finite Element Simulation of Impact on RCC Water Tank (Partheepan Ganesan, M. V. A. N. Jagadeesh Babu, M. Nizamuddin, T. Sai Ram Kiran)....Pages 113-124
Mix Design and Factors Affecting Strength of Pervious Concrete (Bishnu Kant Shukla, Aakash Gupta)....Pages 125-139
Effects of Change of Material Grade on Building Design (J. Bhattacharjee, Abhishek Payal, Vikrant Jain, Adil Ahmed)....Pages 141-145
Feasibility of Redesigning and Retrofitting of a Structure for Vertical Expansion to Avoid Disasters (J. Bhattacharjee, Kratika Sharma, Saahil Bader)....Pages 147-161
Comparison of Number of Piles Required for Deep Foundation Design Using Indian and European Codes (Modita Kulshrestha, Altaf Usmani, Rajan Srivastava)....Pages 163-170
Comparative Analysis of Cement Mortar Roof Tiles Using Agricultural Waste (Prakhar Duggal, Bishwajeet Yadav, Harsh Choudhry, Arpit Garg)....Pages 171-176
Use of Waste Plastic in Wearing Course of Flexible Pavement (Prakhar Duggal, Avneesh Singh Shisodia, Suparna Havelia, Keshav Jolly)....Pages 177-187
Influence of Silpozz on the Properties of Self-Compacting Recycled Aggregate Concrete (M. Mishra, K. C. Panda)....Pages 189-199
Comparative Study on Dynamic Behaviour of RC Building With Conventional and Flat Slab (G. Sridevi, Antaratana Shivaraj, Gouda Sudarshan, Umesh Biradar)....Pages 201-209
Evaluation of Separation Gap between Multi-storey Buildings Subjected to Dynamic Seismic Load (G. Sridevi, Umesh Biradar, Gouda Sudarshan, Antaratana Shivaraj)....Pages 211-220
Characterizing the Rutting Behaviour of Reinforced Cold Mix Asphalt with Natural and Synthetic Fibres Using Finite Element Analysis (Hayder Kamil Shanbara, Ali Shubbar, Felicite Ruddock, William Atherton)....Pages 221-227
Design for FRP-Based Structural Strengthening: How Safe Is Safe Enough? (Kunal D. Kansara, Tim Ibell)....Pages 229-238
A Relook on Dosage of Basalt Chopped Fibres and Its Influence on Characteristics of Concrete (Sanket Rawat, Rahul Narula, Nitant Upasani, G. Muthukumar)....Pages 239-248

Citation preview

Lecture Notes in Civil Engineering

Sondipon Adhikari B. Bhattacharjee J. Bhattacharjee Editors

Advances in Structural Engineering and Rehabilitation Select Proceedings of TRACE 2018

Lecture Notes in Civil Engineering Volume 38

Series Editors Marco di Prisco, Politecnico di Milano, Milano, Italy Sheng-Hong Chen, School of Water Resources and Hydropower Engineering, Wuhan University, Wuhan, China Ioannis Vayas, Institute of Steel Structures, National Technical University of Athens, Greece Sanjay Kumar Shukla, School of Engineering, Edith Cowan University, Joondalup, WA, Australia Anuj Sharma, Iowa State University, Ames, IA, USA Nagesh Kumar, Department of Civil Engineering, Indian Institute of Science Bangalore, Bangalore, Karnataka, India Chien Ming Wang, School of Civil Engineering, The University of Queensland, Brisbane, QLD, Australia

Lecture Notes in Civil Engineering (LNCE) publishes the latest developments in Civil Engineering - quickly, informally and in top quality. Though original research reported in proceedings and post-proceedings represents the core of LNCE, edited volumes of exceptionally high quality and interest may also be considered for publication. Volumes published in LNCE embrace all aspects and subfields of, as well as new challenges in, Civil Engineering. Topics in the series include: – – – – – – – – – – – – – –

Construction and Structural Mechanics Building Materials Concrete, Steel and Timber Structures Geotechnical Engineering Earthquake Engineering Coastal Engineering Hydraulics, Hydrology and Water Resources Engineering Environmental Engineering and Sustainability Structural Health and Monitoring Surveying and Geographical Information Systems Heating, Ventilation and Air Conditioning (HVAC) Transportation and Traffic Risk Analysis Safety and Security

To submit a proposal or request further information, please contact the appropriate Springer Editor: – – – –

Mr. Pierpaolo Riva at [email protected] (Europe and Americas); Ms. Swati Meherishi at [email protected] (India); Ms. Li Shen at [email protected] (China); Dr. Loyola D’Silva at [email protected] (S-E Asia and Australia/NZ). Indexed by Scopus

More information about this series at http://www.springer.com/series/15087

Sondipon Adhikari B. Bhattacharjee J. Bhattacharjee •



Editors

Advances in Structural Engineering and Rehabilitation Select Proceedings of TRACE 2018

123

Editors Sondipon Adhikari Swansea University Swansea, Wales, UK

B. Bhattacharjee Indian Institute of Technology Delhi New Delhi, India

J. Bhattacharjee Amity University Noida, India

ISSN 2366-2557 ISSN 2366-2565 (electronic) Lecture Notes in Civil Engineering ISBN 978-981-13-7614-6 ISBN 978-981-13-7615-3 (eBook) https://doi.org/10.1007/978-981-13-7615-3 © Springer Nature Singapore Pte Ltd. 2020 This work is subject to copyright. All rights are reserved by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. The publisher, the authors and the editors are safe to assume that the advice and information in this book are believed to be true and accurate at the date of publication. Neither the publisher nor the authors or the editors give a warranty, expressed or implied, with respect to the material contained herein or for any errors or omissions that may have been made. The publisher remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. This Springer imprint is published by the registered company Springer Nature Singapore Pte Ltd. The registered company address is: 152 Beach Road, #21-01/04 Gateway East, Singapore 189721, Singapore

Preface

The world focuses on civil engineering to meet the ever-growing demand to handle rising population, various energy and environmental concerns, and safety of structures and inhabitants. Reckoning the ever-growing demand in the civil engineering sector, the Second International Conference on “Trends and Advancement in Civil Engineering” was hosted by the Department of Civil Engineering, ASET, Amity University, Noida, on August 23 and 24, 2018. The objective of the TRACE-2018 was to provide a platform for researchers, engineers, academicians, and industrial professionals from all over the world to present their research results and development activities over broad spectrum of topics and domains such as building construction, design, smart and green materials, sustainable development of infrastructure, rehabilitation and retrofitting, and application of GIS in civil engineering. Such exposure was helpful for the aspiring engineers and practitioners to share and discuss innovative ideas with field professionals and academicians, both national and international. This conference provided opportunities for the delegates to exchange new ideas and application experiences face to face, to establish business or research relations, and to find global partners for future collaboration. The book on Advances in Structural Engineering and Rehabilitation includes the following: • Covers a wide range of research areas in structural engineering, making it a useful reference resource for researchers, academicians, and practicing engineers. • Presents recent advances in structural engineering along with contributions from top experts in the field. • Includes articles on applications like structural health monitoring, vibration control, nanomaterials, machine learning, and artificial intelligence.

v

vi

Preface

This book includes research articles from pioneer researchers in the field of structural engineering. The articles are peer-reviewed by experts to ensure the best standard of research work. After the rigorous process of review and the subsequent revision by authors, the articles are accepted to be a part of this esteemed book. Swansea, UK New Delhi, India Noida, India

Sondipon Adhikari B. Bhattacharjee J. Bhattacharjee

Acknowledgements

To fulfill the vision of most Honorable Founder President Dr. Ashok K. Chauhan and under the able leadership of Honorable Chancellor Dr. Atul Chauhan, we are honored to organize such prestigious conference which connects the world’s foremost industries with the world’s topmost academia. I want to thank everyone involved in making TRACE-2018 a grand success. I appreciate the indispensable contribution of all the invited speakers and authors from the field as well as the academia. Further, I want to convey my sincere thanks to all the co-editors of the book. I extend my warm gratitude toward all our sponsors: academic partners: Liverpool John Moores University, National University of Malaysia, Springer; industry partner: DIPM; knowledge partners: ICE, WiSE, Indian Association for Structural Engineers, and IGS; gold partner: JK Cement; hospitality partner: BFD Weddings and Events; support partners: Bentley, HEICO, VCL, Shubham Builders, Amaatra Group, and BL Goel and Co. More importantly, I am happy to acknowledge that the research paper publication is planned to be published with Springer. This is in itself a stamp for top quality and originality of work to be presented during this conference. Finally, I compliment my team for their hard work and enthusiasm to make TRACE a grand success story.

Noida, UP, India October 2018

Prof. Dr. J. Bhattacharjee Editor and Co-Chair, TRACE-18 Advisor, Civil Engineering Department Amity University

vii

Contents

Experimental and Numerical Study to Improve Lateral Load Resistance of Masonry Stack . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A. K. Shukla, Saurav and P. R. Maiti Experimental Study of Confined Brick Masonry Building . . . . . . . . . . . A. K. Shukla and P. R. Maiti

1 15

A Stochastic Investigation of Effect of Temperature on Natural Frequencies of Functionally Graded Plates . . . . . . . . . . . . . . . . . . . . . . P. K. Karsh, T. Mukhopadhyay and S. Dey

41

Retrofitting of a Multistoried Building with Earthquake-Resistance Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . J. Bhattacharjee, Harshul Mehta, Shiv Dutt Singh Thakur and Aditya Jain

55

Biological Methods to Achieve Self-healing in Concrete . . . . . . . . . . . . . Sunita Bansal, Raj Kumar Tamang, Prince Bansal and Pratik Bhurtel Finite Element Analysis of Profiled Deck Composite Slab Using ANSYS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Aniket A. Shirgaonkar, Yogesh D. Patil and Hemant S. Patil A Brief Review of Structural Aspects of IS 16700:2017 . . . . . . . . . . . . . Vikalp Gupta, Sanket Rawat, Ravi Kant Mittal and G. Muthukumar Are FRPs the Way Forward for the Blast Retrofitting of Reinforced Concrete Structures? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Aashish Kumar Jha, Abhiroop Goswami and Satadru Das Adhikary

63

73 83

93

Analytical Study of Triple Friction Pendulum Under a Different Hazard Level of Earthquakes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105 Ankit Sodha, Sandeep Vasanwala, Devesh Soni, Shailendra Kumar and Kanan Thakkar

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Contents

Finite Element Simulation of Impact on RCC Water Tank . . . . . . . . . . 113 Partheepan Ganesan, M. V. A. N. Jagadeesh Babu, M. Nizamuddin and T. Sai Ram Kiran Mix Design and Factors Affecting Strength of Pervious Concrete . . . . . 125 Bishnu Kant Shukla and Aakash Gupta Effects of Change of Material Grade on Building Design . . . . . . . . . . . . 141 J. Bhattacharjee, Abhishek Payal, Vikrant Jain and Adil Ahmed Feasibility of Redesigning and Retrofitting of a Structure for Vertical Expansion to Avoid Disasters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147 J. Bhattacharjee, Kratika Sharma and Saahil Bader Comparison of Number of Piles Required for Deep Foundation Design Using Indian and European Codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163 Modita Kulshrestha, Altaf Usmani and Rajan Srivastava Comparative Analysis of Cement Mortar Roof Tiles Using Agricultural Waste . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171 Prakhar Duggal, Bishwajeet Yadav, Harsh Choudhry and Arpit Garg Use of Waste Plastic in Wearing Course of Flexible Pavement . . . . . . . 177 Prakhar Duggal, Avneesh Singh Shisodia, Suparna Havelia and Keshav Jolly Influence of Silpozz on the Properties of Self-Compacting Recycled Aggregate Concrete . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 189 M. Mishra and K. C. Panda Comparative Study on Dynamic Behaviour of RC Building With Conventional and Flat Slab . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201 G. Sridevi, Antaratana Shivaraj, Gouda Sudarshan and Umesh Biradar Evaluation of Separation Gap between Multi-storey Buildings Subjected to Dynamic Seismic Load . . . . . . . . . . . . . . . . . . . . . . . . . . . . 211 G. Sridevi, Umesh Biradar, Gouda Sudarshan and Antaratana Shivaraj Characterizing the Rutting Behaviour of Reinforced Cold Mix Asphalt with Natural and Synthetic Fibres Using Finite Element Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 221 Hayder Kamil Shanbara, Ali Shubbar, Felicite Ruddock and William Atherton Design for FRP-Based Structural Strengthening: How Safe Is Safe Enough? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 229 Kunal D. Kansara and Tim Ibell A Relook on Dosage of Basalt Chopped Fibres and Its Influence on Characteristics of Concrete . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 239 Sanket Rawat, Rahul Narula, Nitant Upasani and G. Muthukumar

About the Editors

Dr. Sondipon Adhikari is a professor at the College of Engineering, Swansea University. He graduated in civil engineering from Bengal Engineering and Science University, Shibpur, Kolkata in 1995 and then completed his M.S. from the Indian Institute of Science, Bangalore in 1997. He obtained his Ph.D. in 2001 from Trinity College, University of Cambridge. He is a recipient of the Wolfson Research Merit Award from the Royal Society and the Philip Leverhulme Prize. Since 2015, he has been a distinguished Visiting Professor at the University of Johannesburg. Dr. Adhikari is currently the Chair of Aerospace Engineering at the College of Engineering, Swansea University, and a fellow of the Royal Aeronautical Society. He has published over 280 articles in peer reviewed international journals and has a h-index of 50 in Scopus. Dr. B. Bhattacharjee is a professor in the Department of Civil Engineering, Indian Institute of Technology, Delhi. After completing his B.Tech. from IIT Kharagpur in 1978, he worked for a short period for Gammon India Limited. Subsequently, he obtained his M.Tech. and Ph.D. from IIT Delhi in 1982 and 1990, respectively. His research interests include corrosion of rebar in concrete, high-performance concrete, microstructure modeling of concrete, chloride ingress, service life prediction and life cycle costing of concrete structures, condition evaluation and health monitoring of structures. He has published 185 articles in international and national journals and conferences. He is on the editorial board of several journals, and is also a Life Member of the Indian Concrete Institute, Indian Society for Construction Materials and Structure, Indian Society for Technical Education, and the American Society of Civil Engineers-India Section (ASCE-IS). Dr. J. Bhattacharjee is a professor and adviser in the Civil Engineering department of Amity University, Noida since 2012. He is a former Chief Engineer and Joint Director General, Ministry of Defense. He obtained his bachelors in civil engineering from Bengal Engineering College, Shibpur, Kolkata, M.Tech. from IIT Madras, and M.Phil. from Madras University. He did his Ph.D. in disaster management. He has a vast experience of over 46 years in the industry in planning, xi

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About the Editors

designing and execution of various types of civil engineering works including about 5 years in the multinational consultancy organization Gherzi Eastern Ltd. He has also published about 100 articles in various national and international journals and conferences. Dr. Bhattacharjee received two prestigious Awards for Excellence from Indian Building Congress. He has also developed and taught a number of new courses at the graduate and postgraduate levels at Amity University. He is a Life Member of 16 technical bodies in India and abroad, and is a governing council member of the Indian Building Congress. He has authored a book entitled Concrete Structures – Repair, Rehabilitation and Retrofitting.

Experimental and Numerical Study to Improve Lateral Load Resistance of Masonry Stack A. K. Shukla , Saurav

and P. R. Maiti

Abstract Lateral load capacity of any structure plays a very important role to resist earthquake [1]. To understand the lateral load capacity of any low-rise masonry building, a 3D finite element model of unconfined brick masonry stack has been drawn here. The ANSYS modeling of plain brick masonry shows that masonry structure fails at the joint. Therefore, to impart ductility and strength in the stack, shear key of 4 mm diameter TMT bar of 1/8th, 1/6th, and 1/4th of longitudinal length of brick length is provided at every joint separately in different samples and performance of both confined and unconfined prism is tested against vertical and horizontal load [2]. The purpose of this study was to develop a better behavior of low-rise masonry building during earthquake. Numerical as well as experimental methods have been adapted to calculate the stress developed in masonry stack [3]. Keywords Masonry structure · Confined masonry · Unconfined masonry · FEM analysis of masonry structure

1 Introduction Unconfined masonry was used in approx. all types of structure since the life begins [4]. The masonry structures were made by two basic materials: brick and stone. These structures were not reinforced and designed to support mainly gravity loads. These masonry structures were very good at resisting wind and earthquakes. Masonry building has shown very poor performance during strong earthquake, so it is very important to improve the lateral load resistance of masonry buildings [5]. So to achieve this objective, many researches have been performed in the past. The main A. K. Shukla (B) · P. R. Maiti Indian Institute of Technology (IIT-BHU), Varanasi 221005, India e-mail: [email protected] Saurav Jaypee University of Information Technology, Solan, HP, India © Springer Nature Singapore Pte Ltd. 2020 S. Adhikari et al. (eds.), Advances in Structural Engineering and Rehabilitation, Lecture Notes in Civil Engineering 38, https://doi.org/10.1007/978-981-13-7615-3_1

1

2

A. K. Shukla et al.

focus is on ensuring that these inertial forces caused by the ground vibrations reach the ground without causing major damage or complete collapse in the structures [6]. This research starts with analyzing the scaled unconfined model of four bricks on shake table in laboratory and then confined the same four brick model with varying diameter reinforced to strengthening the unconfined brick model to resist the lateral load [7]. And when the confined models were tested on shake table and compared the result with unconfined brick masonry, a significant lateral strength was observed.

2 Modeling of Structure 2.1 Choice of Elements The ANSYS software contains more than 100 different element types in its element library. Each element has a unique number and a prefix that identifies the element category, such as BEAM3, PLANE42, and SOLID45. ANSYS classifies the elements into 21 different groups, out of which our main concern is of structural group. SOLID45 is used for the 3D modeling of solid structures [8]. The element is defined by eight nodes having three degrees of freedom at each node: translations in the nodal x, y, and z directions. The element has plasticity, creep, swelling, stress stiffening, large deflection, and large strain capabilities [9].

2.2 Material Properties For the brick element material properties which are assigned are modulus of elasticity (EX) and Poisson’s ratio (PRXY) [10]. Values of EX and PRXY are taken according to Ali and page 1986 [5] and are tabulated below (Tables 1 and 2).

Table 1 Material properties of bricks

Properties

Mean

(a) Bricks Modulus of elasticity

14,700 MPa

Poisson’s ratio

0.16

Tensile strength

1.20 MPa

Experimental and Numerical Study to Improve Lateral Load … Table 2 Material properties of mortar

Properties

3

Mean

(a) Mortar Modulus of elasticity

7400 MPa

Poisson’s ratio

0.21

Tensile strength

0.78 MPa

Fig. 1 Model of specimen M1

2.2.1

Model Detail of Specimen

To model the masonry, rectangular blocks are used for bricks and also for mortar. Four numbers of bricks of standard size, i.e., 190 mm × 90 mm × 90 mm are used, and mortar of thickness 10 mm is placed in between them as shown in Figs. 1 and 2.

2.3 Result and Discussion Postprocessing includes defining boundary condition and application of loads. For specimen M1, the one end of the brick masonry is fixed. The load is applied on the other end of the blocks. Pressure loads of 70 kN, 80 kN, and 90 kN are applied on the top face of the brick masonry. In addition to the vertical load, horizontal load is

4

Fig. 2 Model of specimen M2

Fig. 3 X-component of stress on UTM and ANSYS

A. K. Shukla et al.

Experimental and Numerical Study to Improve Lateral Load …

5

Fig. 4 XZ shear stress

also applied to the specimen M1. Different stress contours are drawn, and graph has been plotted between different parameters. For specimen M2 in Fig. 2, one end is fixed to make it confined and vertical load is applied.

2.4 Stress Computation Stress computation for specimen M1 with vertical loading From Fig. 3, it can be seen that X component of stress is maximum at the middle points. It increases parabolically from ends toward the center. For middle bricks, this stress is more as compared to top and bottom bricks. Figures 4 and 5 show that the maximum stress is at the joint of brick mortar in XZ direction. It can be observed in Figs. 6 and 7 that shear stress increases with distance along Y-axis. At a distance of 90 mm, stress is approximately 1400 MPa but from 90 to 100 mm, i.e., at the level of mortar, it decreases abruptly to −1563 MPa. Maximum shear stress is also observed at 28 mm which is equal to 1693 MPa.

6

Fig. 5 Variation of XZ shear stress Y-axis

Fig. 6 Von Misses stress along Y-axis

A. K. Shukla et al.

Experimental and Numerical Study to Improve Lateral Load …

7

Fig. 7 Variation of Von Misses stress along Y-axis

3 Experimental Investigation For confinement of the masonry prism, TMT steel bars of 4 mm diameter were used. Between every course, shear keys of 26.25 mm = 1/8th, 35 mm = 1/6th, 52.5 mm = 1/4th of longitudinal length of brick length consecutively in different specimens were used as shown in Fig. 8a–c.

3.1 Compressive Strength For determination of compressive strength, bricks were taken out from curing tank and tested in UTM (Figs. 9 and 10). Tests were carried out at 7, 14, and 28 days of curing.

3.2 Testing of Masonry in Universal Testing Machine Different Stresses at Failure for Confined and Unconfined Masonry are tabulated below in Table 3.

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A. K. Shukla et al.

Fig. 8 a and b Schematic view of masonry prism. c Pictorial view of reinforcement used Table 3 Compressive strengths at failure Compressive stress at failure Prism type

Strength in MPa of stack after 7 Days

Unconfined brick masonry Confined brick masonry

14 Days

28 Days

4.32

6.02

6.66

Shear key length 26.25 mm

5.80

9.19

10.33

Shear key length 35.00 mm

6.47

9.19

10.33

Shear key length 52.50 mm

7.61

10.42

12.14

Experimental and Numerical Study to Improve Lateral Load … Fig. 9 Unconfined masonry failure

Fig. 10 Confined masonry failure

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10

A. K. Shukla et al.

Fig. 11 Experiments performed on shake table

For understanding the behavior of masonry prism against lateral loading, i.e., in earthquake or in wind load, shaker table test with varying frequency was performed. The unconfined brick masonry samples were put on the shaker table platform and fixed with the help of clamp (Fig. 11). After fixing unconfined masonry tightly on the platform, a frequency of 5 Hz and amplitude of 10 mm was set and the motor was run on this frequency for at least 120 s.

3.3 Testing of Structure Under Horizontal Load: Shake Table Results All the samples including confined and unconfined masonry are tested under the horizontal load using the unidirectional shake table with varying frequency and amplitude as shown in Fig. 11. The result is tabulated in Table 4.

4 Results and Discussion When brick was tested under universal testing machine (UTM), the average strength of brick was found to be 9.21 N/mm2 and strength of cement sand mortar was found to be 14.57 N/mm2 at 28 days of curing. So material was found according to weak brick strong mortar theory. Test conclusion of unconfined and confined brick masonry tested under universal testing machine and under shake table test is summarized below in Table 5.

Frequency of shake table (Hz)

0.3

0.4

0.5

0.6

S. No.

1

2

3

4

Stability analysis

10

7.5

5.0

2.5

Amplitude (mm)

Table 4 Shake table test results

2

2

2

2

‘g’ value

Collapse

Stable

Stable

Stability

26

120

120

Time (in s)

Unconfined brick masonry

120

120

120

Cracking seems at joints after 80th s

Stable

Stable

Stable

Time (in s)

120

120

120

Time (in s)

Very small cracking pattern observed at joint after 360 s

Stable

Stable

Stable

Stability

Brick masonry (shear key = 35 mm)

Brick masonry (shear key = 26.25 mm) Stability

Confined

Confined

Stable

Stable

Stable

Stable

Stability

360

120

120

120

Time

Brick masonry (shear key = 52.5 mm)

Confined

Experimental and Numerical Study to Improve Lateral Load … 11

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A. K. Shukla et al.

Table 5 Result of UTM and shake table S. No.

Sample (after 28 days)

Failure load KN

1

Unconfined masonry prism

2

Stability on shake table Frequency (Hz)

Amplitude (mm)

Remarks

137

15

35

Total Collapse at 26th s

Confined with shear key 26.25 mm

217

20

50

Cracking at 80th s

3

Confined with shear key 35.00 mm

230

20

50

Very small cracking at 360th s

4

Confined with shear key 52.50 mm

255

20

50

Stable after 360 s

Stress analysis of confined & unconfined Masonry Prism at 7,14 & 28 Days Green- 7 day, Blue-14 days, Yellow- 28 days 8 6 4 2 0 Unconfined

Shear key 26.25mm Shear key 35mm Shear key 52.5mm Sample Type

Chart 1 Stress analysis

5 Conclusion After analyzing Chart 1 of performance of confined and unconfined brick masonry, it is concluded that the stress capacity of unconfined brick masonry at 28 days of curing was found to be 6.6 N/mm2 while after confinement, stress capacity increased to 12.14 N/mm2 for shear key length 52.5(1/4th of sample length) mm, i.e., the compressive load capacity of confined brick masonry was approximately doubled of unconfined brick masonry structure at 28 days. But if we look the shake table result, then we found that this stack does not show any crack even after the application of vibration for 360 s. From the experimental study, it can be concluded that the brick stack with shear key length 1/6th of longitudinal length will be an economical solution for confinement.

Experimental and Numerical Study to Improve Lateral Load …

13

References 1. Page AW, Brooks DS (1985) Load bearing masonry—review. In: Proceedings of the 7th international brick masonry conference, pp 81–99 2. Drysdale RG, Wong HE (1985) Interpretation of the compressive strength of masonry prisms. In: Proceedings of the 7th international brick masonry conference 3. Suter GT, Naguib EMF (1987) Effect of brick stiyness orrhorrapy on the lateral stress in stuckbonded brick masonry prisms. In: Proceedings, fourth North American masonry conference, paper 18 4. Khoo CL, Hendry AW (1973) A failure criterion for brick work in axial compression. In: Proceedings of the 3rd international brick masonry conference 5. Ali S, Page AW (1988) Finite element model for masonry subjected to concentrated loads. J Struct Div ASCE 114(8):1761–1784 6. Rots JG (1991) Computer simulation of masonry structure: continuum and discontinuum models. In: Proceedings of the international symposium on computer methods in structural masonry Swansea, UK, April 1991, pp 93–103 7. Stockl S, Bienvirth H, Kupfer H (1994) The influence of test method on the results of compression tests on mortar. In: Proceedings of the 10th IBMAC, University of Calgary, pp 1397–1406 8. Brooks JJ, Abu Baker BH (1998) The modulus of elasticity of masonry. Br Mason Soc J 12(2) 9. Yoshimura K et al (2004) Experimental study for developing higher seismic performance of brick masonry walls. In: Proceedings of the 13th World conference on earthquake engineering, Vancouver, Canada, Paper No. 1597 10. Mohammed MS (2009) Finite element analysis masonry walls of unreinforced masonry

Experimental Study of Confined Brick Masonry Building A. K. Shukla

and P. R. Maiti

Abstract The frequency of the occurrence of earthquake has risen in the last decade and the casualties with low-rise structure, especially unconfined structure, were very high in comparison to reinforced concrete structure worldwide. In this study, the behaviour of confined building in lateral load has investigated. A confined building model has been constructed in the laboratory with the help of scaled bricks, mortar and reinforcement. The building model is tested on shake table under external excitation force of different magnitudes and frequencies. With the help of PULSE Labshop, the values of displacement, velocity and acceleration are measured at different locations of model. The response of the four-storey building model is measured and presented, and the response of the building is analysed under harmonic vibration. Keywords Building model · Confined masonry · Shake table test · B&K Pulse · Frequency analysis

1 Introduction Confined brick masonry system is an alternate way of constructing low to mediumrise buildings, in this masonry walls are confined by the reinforced cement concrete. As per Euro Code 8, a construction system where plain masonry walls are confined on all four sides by reinforced concrete members or reinforced masonry is called confined brick masonry (CBM). Design philosophy of CBM buildings is adopted such that neither the reinforced concrete nor brick masonry gets damaged in an earthquake. Masonry buildings will be continued to be used because of its low cost, thermal and sound insulation, easily availability, and good lateral and vertical loading resistance. But the performance of non-confined brick masonry system is quite bad under the seismic loading, the sudden collapse of buildings leads to great loss to the lives and money, and hence, there arises a demand of low-cost earthquake-resistant A. K. Shukla (B) · P. R. Maiti Indian Institute of Technology (IIT-BHU), Varanasi 221005, India e-mail: [email protected] © Springer Nature Singapore Pte Ltd. 2020 S. Adhikari et al. (eds.), Advances in Structural Engineering and Rehabilitation, Lecture Notes in Civil Engineering 38, https://doi.org/10.1007/978-981-13-7615-3_2

15

16

A. K. Shukla and P. R. Maiti

building system. The use of confined brick masonry system fulfils this demand up to a good level for low to medium-rise buildings. San Bartolomé et al. [1], in his research work, used reduced scale (1:2.5) confined brick masonry building of three storey height made up of clay masonry, whose walls were confined by reinforced concrete elements. The weight of the specimen was 57.78 kN. He kept vibration properties, strength of materials and axial stress of the model similar to those of actual buildings. Ishibashi et al. [2], in this paper, used three full-scale confined masonry specimens which were designed and constructed on the basis of the Mexican codes. In the experimental programme, the variable was the flexural coupling between two wall panels. They find that the degree of coupling did not influence the failure mode of the specimen, which was governed by shear failure of the masonry panels. All the models were consisted of two wall units which were made up of clay bricks. Tomaˇzeviˇc [3] two models of a typical confined masonry building as per EURO CODE 8 have been tested on a shaking table which was constructed with a reduced scale of 1:5, and a wall to floor area was kept as 5%. Both models were subjected to a series of simulated ground motions with increased intensity of shaking. They find that diagonal cracks were observed in all stories at maximum resistance state [4]. Also, the rupture of the reinforcement of tie column and crushing of concrete was also observed at the ultimate state. Abrams [5], in the University of Illinois, tested two reducedscale unreinforced masonry buildings on shake table to highlight selected aspects of dynamic response that helps in confirming or denying engineering practices for seismic evaluation of unreinforced buildings. A scale of 3:8 and type O mortar was used for constructing models of clay masonry units in running bond pattern. Naseer [6], in his research work, determines the behaviour of typical confined brick masonry building under seismic loading, and he also evaluated response modification factor and ductility ratio of the confined brick masonry model. He presented failure mechanism and behaviour of confined masonry buildings during past earthquakes all over the world. Kazemi et al. [7] made a single-storey model full-scale unreinforced confined brick masonry building on the shaking table facility of 4 × 4 m dimensions. It consists of four brick masonry walls conned with reinforced mortar tie columns and steel bond beams. The model was subjected to the scaled earthquake records of Bam, Tabas and El Centro, as well as a harmonic acceleration with gradually increasing amplitude.

2 Building of Model The building model on geometrically reduced scale of 1/8th is prepared in the structural engineering laboratory of IIT (BHU) Varanasi. The property of the model is as follows:

Experimental Study of Confined Brick Masonry Building

17

Length—355 mm, width—345 mm, storey height—350 mm Openings Door width—85 mm, window width—75 mm, door height—225 mm, window height—130 mm Weight Calculation of the Single Storey Thickness of the walls = 25 mm, height of the walls = 350 mm, length of walls = 350 mm Volume of building = 4 × (25 × 350 × 350 − 25 × 25 × 350) = 1.137 × 107 mm3 Opening deductions Door opening (25 × 85 × 225) = 4.78 × 105 mm3 , window opening 2 × (75 × 25 × 130) = 4.87 × 105 mm3 Volume of columns—4 × 25 × 25 × 350 = 8.75 × 105 mm3 So total volume of the brickwork = 1.137 × 107 − (4.78 + 4.87 + 8.75) × 105 mm3 = 9.53 × 106 mm3 Since volume of one brick with mortar = 31 × 16 × 11 = 5456 mm3 Hence, the number of bricks used = 1750 (approximately) Weight of one brick = 9.5 g, so weight of brickwork = 1750 × 9.5 = 16,625 g = 16.6 kg Weight of mortar = 0.02 × 9.02 × 10−3 × 1750 = 0.3157 kg Weight of column and slab (concrete work) = (25 × 25 × 350 + 10 × 350 × 350) × 2.4 × 10−6 = 3.465 kg Hence total weight of single storey = weight of (brickwork + mortar + concrete work) = 16.6 + 0.3157 + 3.465 = 20.38 kg Total weight of the building model = 20.38 × 4 = 81.5 kg

2.1 Plan of the CBM Model The CBM model is a 350 mm × 350 mm G+3 storey model with four openings, out of which two doors of width 85 mm are provided on the opposite sides and two windows of width 75 mm on the other two walls (Fig. 1). Wall density of the CBM model—Wall density is defined as the ratio of total cross-sectional area of all walls in one direction to the total floor area. Since floor area of each floor = 350 × 350 = 122, 500 mm2 Total floor area for 4 floors = 4 × 122, 500 = 490, 000 mm2 Wall density in the longitudinal direction (parallel of windows)

18

A. K. Shukla and P. R. Maiti

Fig. 1 Plan of the CBM model

Two wall area = (350 − 75) × 2 × 25 = 13,750 mm2 i.e. Wall Density in longitudinal direction =

13, 750 490, 000

= 0.028 = 2.8 %

Hence, wall density in longitudinal direction 2.8% is larger than 2%, in which the minimum value is required for buildings located in the seismic zone III of India. Wall density in the longitudinal direction (parallel of doors) Two wall area = (350 − 85) × 2 × 2 = 13, 250 mm2 , 13, 250 Hence wall density = = 0.027 % 490, 000 Hence, it also fulfils the minimum value of 2% required for buildings located in the seismic zone III of India.

2.2 Reinforcement Detailing of the Model The detail of reinforcement of the CBM model is as follow (Table 1).

Experimental Study of Confined Brick Masonry Building

19

Table 1 Reinforcement detailing of the model S. No.

Elements

Diameter of rebar’s

Spacing/numbers

Diameter of wire

1

Lateral ties

6 mm

2 legged @ 17 mm c/c

1.2 mm

2

Column reinforcement

12 mm

4 mm

2.4 mm

3

Slab reinforcement

8 mm

22 mm c/c

1.6 mm

4

Beam reinforcement

12 mm

NA

2.4 mm

5

Stirrups

6 mm

2 legged @ 17 mm c/c

1.2 mm

6

Binding wire

22 gauge

NA

26 gauge

Fig. 2 Brick used in model

2.3 Making of CBM Model The model was prepared using the small clay bricks of dimensions 30 mm × 15 mm × 10 mm; approximately 1750 numbers of bricks were used in constructing G+3storey model. The mechanical properties of the bricks are as same as the conventional bricks (Figs. 2 and 3).

20

A. K. Shukla and P. R. Maiti

Fig. 3 Confined masonry model

3 Experimental Investigation 3.1 Shake Table Test To study the dynamic behaviour of confined masonry building, the model was tested on shake table under different combinations of magnitude and frequency. With the help of PULSE Labshop, the values of displacement, velocity and acceleration are measured under different values of magnitude and frequency (Fig. 4). No cracks were seen throw the naked eye inspection. It was fixed to the shake table without creating a damage to the model. The inspection was done after fixing the model on the shake table, and no cracks were seen again.

3.2 The Response of the Model Under Different Variable Magnitudes and Frequencies Case 1. When accelerometer attached at different floors All six accelerometers were attached at different floors at magnitude 5 mm and with varying frequency. The result in the terms of displacement, velocity and acceleration is obtained (Tables 2, 3 and 4; Charts 1, 2 and 3).

Experimental Study of Confined Brick Masonry Building

21

Fig. 4 Model on shake table and accelerometers at different locations Table 2 Magnitude 5 mm and frequency 0.4 Hz Accelerometer Magnitude No. (mm)

Frequency (Hz)

Displacement (mm)

Velocity (mm/s)

Acceleration (m/s2 )

1

5

0.4

5

16

0.55

2

5

0.4

3.3

11

0.50

3

5

0.4

3.5

16

1.10

4

5

0.4

2.50

20

1.35

5

5

0.4

3.40

20

1.30

6

5

0.4

1.00

2.4

0.15

22

A. K. Shukla and P. R. Maiti

12 10 8 6

Magni 5 Freq 0.4 Magni 5 Freq 0.5

4

Magni 5 Freq 0.6

2 0 ACCELERO 1 ACCELERO 2

ACCELERO 3 ACCELERO 4 ACCELERO 5 ACCELERO 6 Accelerometer

Chart 1 Displacement in accelerometers at five magnitudes and at different frequencies 35 30 25 Magni 5 Freq 0.4

20

Magni 5 Freq 0.5

15

Magni 5 Freq 0.6

10 5 0 ACCELERO 1

ACCELERO 2

ACCELERO 3 ACCELERO 6 Accelerometer

ACCELERO 4

ACCELERO 5

Chart 2 Velocities in accelerometers at five magnitudes and at different frequencies 3.5

3 2.5

2 Magni 5 Freq 0.4 1.5

Magni 5 Freq 0.5

1

Magni 5 Freq 0.6

0.5

0 ACCELERO 1 ACCELERO 2

ACCELERO 3 ACCELERO 4 ACCELERO 5 ACCELERO 6 Accelerometer

Chart 3 Acceleration in accelerometers at five magnitudes and at different frequencies

Experimental Study of Confined Brick Masonry Building

23

Table 3 Magnitude 5 mm and frequency 0.5 Hz Accelerometer Magnitude No. (mm)

Frequency (Hz)

Displacement (mm)

Velocity (mm/s)

Acceleration (m/s2 )

1

5

0.5

6

20

0.70

2

5

0.5

4.1

21

0.70

3

5

0.5

4.0

20

1.10

4

5

0.5

3.8

22

1.70

5

5

0.5

3.8

26

1.90

6

5

0.5

0.75

2.7

0.16

Table 4 Magnitude 5 mm and frequency 0.6 Hz Accelerometer Magnitude No. (mm)

Frequency (Hz)

Displacement (mm)

Velocity (mm/s)

Acceleration (m/s2 )

1

5

0.6

4.8

24

1.00

2

5

0.6

5.0

26

1.00

3

5

0.6

6.0

26

3.50

4

5

0.6

4.0

30

1.80

5

5

0.6

5.5

38

2.60

6

5

0.6

0.80

5.4

0.33

Fig. 5 Top floor (G+3) accelerometers attachment

Case 2. Accelerometers Attached on the G+3 Floor Six accelerometer was attached on the top floors at different locations of the walls and slab (Fig. 5; Tables 5, 6 and 7; Charts 4, 5 and 6).

24

A. K. Shukla and P. R. Maiti

12 10 8 6

Magni 5 Freq 0.4

Magni 5 Freq 0.5

4

Magni 5 Freq 0.6 2 0

ACCELERO 1 ACCELERO 2 ACCELERO 3 ACCELERO 4 ACCELERO 5 ACCELERO 6 Accelerometer

Chart 4 Displacement in accelerometers at five magnitudes and at different frequencies 60

Velocity (mm/sec)

50 40 Magni 5 Freq 0.3

30

Magni 5 Freq 0.4 Magni 5 Freq 0.5

20

Magni 5 Freq 0.6

10 0 1

2

3

4

5

6

Accelerometer

Chart 5 Velocities in accelerometers at five magnitudes and at different frequencies 3 2.5 2

Magni 5 Freq 0.3

1.5

Magni 5 Freq 0.4

1

Magni 5 Freq 0.5 Magni 5 Freq 0.6

0.5 0

ACCELERO 1 ACCELERO 2 ACCELERO 3 ACCELERO 4 ACCELERO 5 ACCELERO 6 Accelerometer

Chart 6 Acceleration in accelerometers at five magnitudes and at different frequencies

Experimental Study of Confined Brick Masonry Building

25

Table 5 Magnitude 5 mm and frequency 0.4 Hz Accelerometer Magnitude No. (mm)

Frequency (Hz)

Displacement (mm)

Velocity (mm/s)

Acceleration (m/s2 )

1

5

0.4

3.0

20

1.3

2

5

0.4

3.4

16

1.40

3

5

0.4

6.0

30

2.0

4

5

0.4

6.0

24

1.5

5

5

0.4

3.2

14

1.50

6

5

0.4

0.4

3.0

0.90

Table 6 Magnitude 5 mm and frequency 0.5 Hz Accelerometer Magnitude No. (mm)

Frequency (Hz)

Displacement (mm)

Velocity (mm/s)

Acceleration (m/s2 )

1

5

0.5

4.0

35

2.0

2

5

0.5

4.5

30

2.0

3

5

0.5

8.5

40

2.0

4

5

0.5

8.0

32

2.0

5

5

0.5

4.5

28

1.9

6

5

0.5

1.30

3.4

0.21

Table 7 Magnitude 5 mm and frequency 0.6 Hz Accelerometer Magnitude No. (mm)

Frequency (Hz)

Displacement (mm)

Velocity (mm/s)

Acceleration (m/s2 )

1

5

0.6

8.6

50

2.4

2

5

0.6

6.5

45

2.8

3

5

0.6

10

55

2.8

4

5

0.6

10

52

2.2

5

5

0.6

6.0

42

2.2

6

5

0.6

1.1

3.7

0.40

Case 3. Accelerometers Attached On the G+2 Floor (See Fig. 6; Tables 8, 9 and 10; Charts 7, 8 and 9). Case 4. Accelerometers Attached On the G+1 Floor (See Fig. 7; Tables 11, 12 and 13; Charts 10, 11 and 12). Case 5. Accelerometers Attached On the Ground Floor (See Fig. 8; Tables 14, 15 and 16; Charts 13, 14 and 15). From the above tables, it is clear that the values of displacement, velocity and acceleration depend upon the magnitude and frequency of the shake table. Even the values are different at different locations on the same floor also.

26

A. K. Shukla and P. R. Maiti

Fig. 6 Accelerometers attached at G+2 floor Table 8 Magnitude 5 mm and frequency 0.4 Hz Accelerometer Magnitude No. (mm)

Frequency (Hz)

Displacement (mm)

Velocity (mm/s)

Acceleration (m/s2 )

1

5

0.4

5.0

20

1.100

2

5

0.4

3.0

16

1.100

3

5

0.4

5.50

22

1.350

4

5

0.4

5.20

22

1.200

5

5

0.4

2.90

13

1.000

6

5

0.4

0.05

2.8

0.110

Table 9 Magnitude 5 mm and frequency 0.5 Hz Accelerometer Magnitude No. (mm)

Frequency (Hz)

Displacement (mm)

Velocity (mm/s)

Acceleration (m/s2 )

1

5

0.5

6.20

35

2.200

2

5

0.5

5.50

40

1.900

3

5

0.5

9.20

60

1.900

4

5

0.5

9.00

45

1.700

5

5

0.5

5.50

38

1.600

6

5

0.5

1.00

3.8

0.320

Experimental Study of Confined Brick Masonry Building

27

Table 10 Magnitude 5 mm and frequency 0.6 Hz Accelerometer Magnitude No. (mm)

Frequency (Hz)

Displacement (mm)

Velocity (mm/s)

Acceleration (m/s2 )

1

5

0.6

5.0

25

2.500

2

5

0.6

4.0

26

1.500

3

5

0.6

8.0

30

1.600

4

5

0.6

7.20

30

1.600

5

5

0.6

4.00

24

1.400

6

5

0.6

0.06

3.8

0.280

10 9 8 7 6 5

Magni 5 Freq 0.4

4 3

Magni 5 Freq 0.5 Magni 5 Freq 0.6

2 1 0 ACCELERO 1 ACCELERO 2

ACCELERO 3 ACCELERO 4 ACCELERO 5 ACCELERO 6 Accelerometer

Chart 7 Displacement in accelerometers at five magnitudes and at different frequencies 70

Velocity (mm/sec)

60 50 40 Magni 5 Freq 0.4 30

Magni 5 Freq 0.5

20

Magni 5 Freq 0.6

10 0 1

2

3

4

5

6

AccleraƟon

Chart 8 Velocities in accelerometers at five magnitudes and at different frequencies

28

A. K. Shukla and P. R. Maiti 3

AcceleraƟon (m/sec2)

2.5 2 Magni 5 Freq 0.4

1.5

Magni 5 Freq 0.5 1

Magni 5 Freq 0.6

0.5 0 1

2

3

4

5

6

Axis Title

Chart 9 Acceleration in accelerometers at five magnitudes and at different frequencies

Fig. 7 Accelerometers attached at G+1 floor Table 11 Magnitude 5 mm and frequency 0.4 Hz Accelerometer Magnitude No. (mm)

Frequency (Hz)

Displacement (mm)

Velocity (mm/s)

Acceleration (m/s2 )

1

5

0.4

5.0

20

0.80

2

5

0.4

4.5

17

0.70

3

5

0.4

4.0

20

0.80

4

5

0.4

4.5

18

0.60

5

5

0.4

4.5

17

0.50

6

5

0.4

0.80

3.3

0.75

Experimental Study of Confined Brick Masonry Building

29

Table 12 Magnitude 5 mm and frequency 0.5 Hz Accelerometer Magnitude No. (mm)

Frequency (Hz)

Displacement (mm)

Velocity (mm/s)

Acceleration (m/s2 )

1

5

0.5

8.0

30

0.50

2

5

0.5

6.0

26

1.10

3

5

0.5

7.0

30

0.90

4

5

0.5

6.8

26

1.00

5

5

0.5

6.5

22

0.70

6

5

0.5

0.64

30

0.30

Table 13 Magnitude 5 mm and frequency 0.6 Hz Accelerometer Magnitude No. (mm)

Frequency (Hz)

Displacement (mm)

Velocity (mm/s)

Acceleration (m/s2 )

1

5

0.6

9

35

1.20

2

5

0.6

7.50

35

1.20

3

5

0.6

8.8

45

1.00

4

5

0.6

7.8

36

1.10

5

5

0.6

7.5

34

1.20

6

5

0.6

0.6

2.6

0.34

10 9 8 7 6 5 4 3 2 1 0

Magni 5 Freq 0.4 Magni 5 Freq 0.5 Magni 5 Freq 0.6

ACCELERO 1 ACCELERO 2

ACCELERO 3 ACCELERO 4 ACCELERO 5 ACCELERO 6 Accelerometer

Chart 10 Displacement in accelerometers at five magnitudes and at different frequencies Table 14 Magnitude 5 mm and frequency 0.4 Hz Accelerometer Magnitude No. (mm)

Frequency (Hz)

Displacement (mm)

Velocity (mm/s)

Acceleration (m/s2 )

1

5

0.4

3.7

10

0.60

2

5

0.4

4.0

11

0.60

3

5

0.4

3.7

10.5

0.60

4

5

0.4

3.6

12.0

0.55

5

5

0.4

4.5

13

0.65

6

5

0.4

0.95

3.0

0.05

30

A. K. Shukla and P. R. Maiti 60

Velocity (mm/sec)

50 40 30

Magni 5 Freq 0.4 Magni 5 Freq 0.5

20

Magni 5 Freq 0.6

10 0 1

2

3

4

5

6

Accelerometer

Chart 11 Velocities in accelerometers at five magnitudes and at different frequencies 3 2.5 2 1.5

Magni 5 Freq 0.4 Magni 5 Freq 0.5

1

Magni 5 Freq 0.6

0.5 0

ACCELERO 1 ACCELERO 2

ACCELERO 3 ACCELERO 4 ACCELERO 5 ACCELERO 6 Accelerometer

Chart 12 Acceleration in accelerometers at five magnitudes and at different frequencies Table 15 Magnitude 5 mm and frequency 0.5 Hz Accelerometer Magnitude No. (mm)

Frequency (Hz)

Displacement (mm)

Velocity (mm/s)

Acceleration (m/s2 )

1

5

0.5

6.0

16

0.90

2

5

0.5

5.5

17

1.00

3

5

0.5

5.5

18

0.60

4

5

0.5

5.0

18

0.80

5

5

0.5

6.0

17

0.80

6

5

0.5

0.6

2.8

0.08

Experimental Study of Confined Brick Masonry Building

31

Fig. 8 Accelerometers attached at ground floor Table 16 Magnitude 5 mm and frequency 0.6 Hz Accelerometer Magnitude No. (mm)

Frequency (Hz)

Displacement (mm)

Velocity (mm/s)

Acceleration (m/s2 )

1

5

0.6

7.00

24

1.00

2

5

0.6

6.00

24

1.00

3

5

0.6

6.00

25

0.60

4

5

0.6

6.50

24

1.00

5

5

0.6

6.50

24

0.80

6

5

0.6

0.70

3.2

0.08

8 7 6 5 4

Magni 5 Freq 0.4

3

Magni 5 Freq 0.5

2

Magni 5 Freq 0.6

1 0

ACCELERO 1 ACCELERO 2 ACCELERO 3

ACCELERO 4 ACCELERO 5 ACCELERO 6

Accelerometer

Chart 13 Displacement in accelerometers at five magnitudes and at different frequencies

32

A. K. Shukla and P. R. Maiti

30 25 20 15

Magni 5 Freq 0.4 Magni 5 Freq 0.5

10

Magni 5 Freq 0.6

5 0 1

2

3

4

5

6

Accelerometer

Chart 14 Velocities in accelerometers at five magnitudes and at different frequencies 1.2 1 0.8

Magni 5 Freq 0.4

0.6

Magni 5 Freq 0.5 0.4

Magni 5 Freq 0.6

0.2 0

ACCELERO 1

ACCELERO 2

ACCELERO 3

ACCELERO 4

ACCELERO 5

ACCELERO 6

Accelerometer

Chart 15 Acceleration in accelerometers at five magnitudes and at different frequencies

3.3 Acceleration Analysis of Model For the analysis of acceleration with respect to time at different locations of building, the accelerometers were attached at desired location on the model (Fig. 9) at the highest excitation force used on model, i.e. magnitude 5 mm and frequency 0.6 Hz. We obtain the following graphs.

3.4 Acceleration Versus Time History for Amplitude—5 mm and Frequency—0.6 Hz (See Graphs 1, 2, 3, 4, 5 and 6).

Experimental Study of Confined Brick Masonry Building

33

Fig. 9 Position of accelerometers on confined masonry building

3.5 Condition of the Model After Test Hairline cracks were appeared after the test; however, no major damage such as shear failure, out-of-plane or roof failure has been seen in the model (Fig. 10). The maximum values of the displacement, velocity and acceleration found at 5.00 mm amplitude and 0.6 Hz frequency obtained are Maximum displacement—6 mm, maximum velocity—38 mm/s, maximum acceleration—3.5 m/s2 or 0.326 g.

34

A. K. Shukla and P. R. Maiti

Graph 1 Acceleration in Test Run 1 in Accelerometer 1

4 Conclusion After performing the experimental study of the confined brick masonry (CBM) model, it may be concluded that its performance is comparatively better than the unreinforced masonry under dynamic loading. Confined brick masonry is a better alternative to both unreinforced masonry and costlier RCC frame structure. The performance of the confined masonry structures performance under the dynamic loading is reasonably good as seen with the help of testing it on shake table, yet hairline cracks appear at the higher frequencies, but it is accepted when we compare

Experimental Study of Confined Brick Masonry Building

35

Graph 2 Acceleration in Test Run 1 in Accelerometer 2

with traditional unreinforced concrete buildings. This type of construction has a good scope in low-cost housing in high seismic risk zones. The following conclusion has been derived after conducting project work 1. The G+3-storey model would withstand in an earthquake even at acceleration of 3.20 m/s2 or 0.326 g level with minor hairline cracks in bricks joints. 2. The performance of confining elements was good; it did not allow out-of-plane failure of the walls.

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A. K. Shukla and P. R. Maiti

Graph 3 Acceleration in Test Run 1 in Accelerometer 3

3. The provisions of Euro code are suitable for constructing the confined brick masonry structures. 4. Toothing in the walls helps to prevent separation of walls from the confining even in large ground motions. 5. Weak mortar joint reduces the performance of the confined brick masonry buildings; hence, strong mortar joint should be provided for constructing the walls of CBM.

Experimental Study of Confined Brick Masonry Building

37

Graph 4 Acceleration in Test Run 1 in Accelerometer 4

5 Recommendations 1. The shape of the building should be regular, and wall should be provided in both directions. 2. Minimum full brick thick walls must be provided to construct confined brick masonry houses. 3. Confining elements of minimum thickness of 150 mm shall be placed in the plane of the wall at every floor level with a vertical spacing of not more than 4 m. 4. As there is no Indian Standard Code for the confined masonry, the application of CBM with locally available materials is difficult in India; hence, it is highly recommended to make a new IS code for CBM.

38

Graph 5 Acceleration in Test Run 1 in Accelerometer 5

A. K. Shukla and P. R. Maiti

Experimental Study of Confined Brick Masonry Building

Graph 6 Acceleration in Test Run 1 in Accelerometer 6

39

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Fig. 10 Hairline cracks in the walls after completion of the test

References 1. San Bartolomé A, Quiun D, Torrealva D (1992) Seismic behaviour of a three-story half scale confined masonry structure. In: Memorias, tenth world conference on earthquake engineering, vol 6, pp 3527–3531 2. Ishibashi K, Meli R, Alcocer SM, Leon F, Sanchez TA (1992) Experimental study on earthquakeresistant design of confined masonry structures. In: Proceedings of the tenth world conference on earthquake engineering, Madrid, Spain, pp 3469–3474 3. Tomaževiˇc M (2000) Shaking table tests of small-scale models of masonry buildings: advantages and disadvantages. In: Massivbau 2000, January 01, pp 67–83 4. Tomazevic M, Bosiljkov V, Weiss P (2004) Structural behavior factor for masonry structures. In: 13th World conference on earthquake engineering, Vancouver, B.C., Canada, paper No. 2642 5. Abrams DP (2000) Seismic response patterns for URM buildings. TMS J 18(1):71–78 6. Naseer A (2009) Performance behavior of confined brick masonry buildings under seismic demand. Diss. University of Engineering and Technology, Peshawar, Pakistan 7. Kazemi MT, Asl MH, Bakhshi A, Rofooei FR (2010) Shaking table study of a full-scale single storey confined brick masonry building

A Stochastic Investigation of Effect of Temperature on Natural Frequencies of Functionally Graded Plates P. K. Karsh , T. Mukhopadhyay

and S. Dey

Abstract The present paper deals with thermal uncertainty quantification in the free vibration of functionally graded materials (FGMs) cantilever plate by using the finite element method coupled with multivariate adaptive regression splines surrogate (MARS) model. The combined effects of uncertainty in material properties on the natural frequency are examined. The power law is employed for gradation of material properties across the depth of FGM plate, while the Touloukian model is used to evaluate temperature effects on the material properties. In finite element analysis (FEA), eight noded iso-parametric elements are considered with each element having five degrees of freedoms. In MARS, Sobol sampling is employed to train the model, which results in better convergence and accuracy. The results of MARS model are validated with Monte Carlo simulation results. The results reveal that MARS model can achieve a significant level of accuracy without compromising the accuracy of results. Keywords Finite element method · Monte Carlo simulation · Multivariate adaptive regression splines · Free vibration · Thermal uncertainty · Functionally graded plates

1 Introduction In the microscopic level, FGMs are inhomogeneous in nature, where two materials, namely metal and ceramic, are mixed to obtain the coupled effects material properties. The gradation of material properties is continues and smoothly across the depth without any intermediate joint, which results negligible internal stresses in the structure. Functionally graded materials can withstand higher temperature as compared P. K. Karsh (B) · S. Dey Mechanical Engineering Department, National Institute of Technology Silchar, Silchar, India e-mail: [email protected] T. Mukhopadhyay Department of Engineering Science, University of Oxford, Oxford, UK © Springer Nature Singapore Pte Ltd. 2020 S. Adhikari et al. (eds.), Advances in Structural Engineering and Rehabilitation, Lecture Notes in Civil Engineering 38, https://doi.org/10.1007/978-981-13-7615-3_3

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to conventional composite materials because its one face is metal-rich while another face is ceramic-rich which provides good thermal resistance. Another advantage of FGM over the conventional composites is that it has no interfacial delamination due to the continuous mixture of materials. Therefore, FGM has widespread application in thermal barrier and corrosion resistance coatings for aerospace and fusion reactors [1]. Such advanced materials are often susceptible to various forms of uncertainties [2–9]. The material properties of FGMs are significantly influenced by the environmental temperature. The material properties of FGM may be varied according to different laws such as power law, exponential law and sigmoid law. In this paper, power law is utilized to vary the material properties with power-law exponential equal to one. Many researchers carried out research on the dynamic analysis of FGMs by using a different approach. Hien and Noh determined the natural frequencies of FGM plate by employing the stochastic isogeometric analysis by considering the variation in material properties. The perturbation expansion is used to determine the first two eigenvalues, and results are validated with Monte Carlo Simulation (MCS) [10]. Similarly, Xu et al. conducted the dynamic analysis of FGM beam with random material properties by using the FE method [11]. Shenas et al. determined the effects of temperature of twisted FGM plates on the free vibration by applying the modified strain gradient theory [12]. Zghal et al. employed the discrete double directors shell FEM for the vibration analysis of reinforced FG composite shells [13]. Barzegar and Fadaee conducted the free vibration of FGM shallow spherical caps by using the decoupling technique under the influence of temperature, power-law index and radius of curvature [14]. Wang et al. analytically determined the natural frequencies of the functionally graded beam with different boundary conditions [15], while Rezaiee-Pajand applied numerical and analytical approach for dynamic analysis of double beam systems made of FGM [16]. Chen et al. performed vibration analysis of non-uniform density FGM beams by employing the Ritz method [17], while Xue et al. employed Isogeometric analysis and refined plate theory [18]. Bediz performed dynamic analysis of FG beams, plate and solid by using the spectralTchebychev technique along with Mori–Tanaka method for gradation of material properties across the depth of FGM [19]. The FGMs are used as the sheet and core of the sandwich plate, and free vibration analysis is carried out for higher order natural frequencies by applying higher order sandwich plate theory by Liu et al. [20]. Razavi et al. applied the cylindrical shell model along with the consistent couple stress theory to determine the natural frequencies of FG piezoelectric nano-shell and determined the effects of power-law index, the radius–thickness ratio and the length–radius ratio of dynamic response [21]. As discussed earlier, FGMs are mainly used in the field where temperature variation is high such as a thermal barrier and coatings. With the increase in temperature, the material properties, namely elastic modulus, shear modulus and Poisson’s ration, decreased consequent reduction in the stiffness of the plate. So it is important to assess the effect of uncertainty in material properties due to temperature variation. In this paper, an attempt has been made to determine the effect of temperature on the first three natural frequencies of FGM plates by using the FEM. The MCS [22–29] along with the multivariate adaptive regression splines model is applied for the stochas-

A Stochastic Investigation of Effect of Temperature …

43

Fig. 1 Geometry of functionally graded cantilever plate

tic free vibration of FGM cantilever plates with considering different temperature. Figure 1 illustrates the geometrical properties of functionally graded material cantilever plate with the upper layer is ceramic-rich and the lower layer is metal-rich and flowchart of MARS for free vibration analysis. The coordinates of the plate in three-dimensional space are x, y, z, while t is the thickness, L is length and b is width of FGM plate.

2 Mathematical Formulation The basic dynamic equation of equilibrium for a system given by [30, 31]           M¯ δ + C¯ δ + K¯ {δ} = {F}

(1)

    where M¯ denotes randomized mass matrix, C¯ represents randomized damping       matrix, K¯ is the randomized stiffness matrix, δ  is the acceleration, δ  is the velocity, {δ} is the displacement and {F} is external applied force. For free vibration without damping is given by       M¯ δ + K¯ {δ} = 0

(2)

For free vibration, displacement vector is expressed as {δ} = [φ] sin ωt ¯

(3)

{δ} = −ω¯ 2 [φ] sin ωt ¯

(4)

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where [φ] is the eigenvector or mode shape, ω¯ is the eigenvalue or natural frequency, by putting the values in Eq. (2), we get     −ω¯ 2 M¯ {φ} sin ωt ¯ + K¯ {φ} sin ωt ¯ =0

(5)

    K¯ − ω¯ 2 M¯ {φ} = 0

(6)

The Eq. (6) can be solved by using Eigenvalue solution, and eigenvalue are natural frequencies, while corresponding Eigen vectors are mode shapes. The material constitutes of the FGM are varying throughout the volume. The final material property (R) of FGM is the sum of all material properties given as R=

m 

Ri Vi and i = 1, 2, . . . , m

(7)

i=1

where Ri and Vi represent material properties and volume fraction of individual materials, respectively. There are different distribution laws of material properties in the FGM plate, namely power law, sigmoid law and exponential law. The material properties gradation across the thickness is carried out based on the power-law distribution as follows:

z 1 R(t) = R1 + (R2 − R1 ) + t 2

p (8)

where R1 and R2 represent the material properties of first and second constitute, respectively, R is material properties of FGM plates, p denotes the power-law index or exponent, t is the plate thickness and for lower face of the plate z = −t/2 while for upper face z = t/2. The two constitutes of FGM may be metal and ceramic in which metal gives strength and stiffness while ceramic gives temperature and wear resistance. The final material properties of the FGM depend upon the working temperature which is given by Touloukian model as [32] R = R0 + R−1 T −1 + 1 + R1 T + R2 T 2 + R3 T 3

(9)

where R0 , R−1 , R1 , R2 , R3 are the coefficients of temperature (T ). The unit of temperature (T ) is Kelvin. In the finite element formulation, the plate is discretized into 64 elements by (8 × 8) mesh size, where each element has five degrees of freedom (two rotational and three translational). Each element has eight nodes, so a total of 225 numbers of nodes are considered.

A Stochastic Investigation of Effect of Temperature …

45

3 Multivariate Adaptive Regression Splines Surrogate modelling technique is used to achieve computational efficiency in computationally intensive simulations (where efficient analytical solutions [33–35] are not available, such as finite element modelling) of repetitive nature [36–43]. The MARS establishes the relationship among the input and output response of a system by selecting samples based on few algorithms [44–46]. In MARS, there is no assumption for the functional relationship between independent and dependent variables; instead, it uses a set of coefficients and basic function for establishing the relationship which is taken from regression data. A nonparametric regression algorithm was employed to divide the input space into regions having regression equation. The MARS is mostly employed for the solution of high dimensional input parameter problems, which are difficult to solve by other techniques. A forward and backward approach is employed for selection of the set of basic function for the approximation of output response. The model is initiated with the simple model by considering the constant basis function and then adding the basic functions to increase the complexity of the present model until the predefined complexity is achieved. Then, insignificant basic functions are removed from the model by backward approach [47]. The MARS can be given by X=

M 

βn K nf (yi )

(10)

n=1

where X represents the approximation function, βn represents the coefficients of f expansion and K n (yi ) denotes the multivariate spline basic functions. Input space is divided into M number of regions. The Eq. (10) becomes X = β1

(11)

f

where K n (y1 , y2 , y3 , . . . , ym ) = 1 for n = 1. In Eq. (11), the term β1 is known as intercept parameter. The basic function can be written as K nf (yi ) =

in 

 g Z i,n y j(i,n) − qi,n Tr

(12)

i=1

where i n represents the interaction order, Z i,n = ±1, y j(i,n) denotes the jth variable, 1 ≤ j(i, n) ≤ m and qi,n represents the knot location of corresponding variables. The dimension of input variables is represented by m, superscript f denotes the function and l denotes splines order. The function X contains the all basic functions of f n subregions, while the multivariate spline basic function K n (yi ) contains univari-

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ate spline basic function and Z i,n . ‘Tr’ represents the function as truncated power function. The basic function may be in the following shapes 

 g  g     Z i,n y j(i,n) − qi,n Tr = Z i,n y j(i,n) − qi,n for Z i,n y j(i,n) − qi,n < 0 (13) 

  Z i,n y j(i,n) − qi,n = 0, Otherwise

(14)

Thus, all basic function can be written as D=



 g    Z i,n y j(i,n) − qi,n Tr , q ∈ y1 j , y2 j , . . . , y M j

(15)

The forward propagation step employed stepwise linear regression like model building strategy, but it uses functions from D and their products instead of original inputs. By minimizing the residual sum of squares, the coefficients of βn are estimated. The MARS algorithm employed forward and backward approach to determine the location and number of spline basic functions. First, spline basic functions are overfitted through each knot, and the modified cross-validation criteria are employed to remove the insignificant knots of the model. For the fast convergence and better prediction of the present model [48, 49], Sobol sampling technique is utilized.

4 MARS-Based Natural Frequency Analysis In the present study, the influence of stochasticity in material properties on the natural frequencies is determined by considering the effect of temperature. So, in the first step of MARS modelling, the different operating temperatures such as 100, 300, 600 and 900 K are considered as input parameters, while first three natural frequencies as output response. In the second step, finite element modelling is carried out with discretizing a cantilever FGM plate into 64 elements with mesh size (8 × 8), where each element has five degrees of freedom. The stochasticity in temperature is considered as input parameters as ¯ = ψ[T, {E(z)}(ω), ¯ {G(z)}(ω), ¯ {ρ(z)}(ω), ¯ {υ(z)}(ω)] ¯ Y1 (T, ω)

(16)

where ψ denotes the symbolic operator for the Monte Carlo simulation considering the individual effect of stochasticity, ω¯ represents the degree of stochasticity and T is the temperature in Kelvin. E is the elastic modulus, G denotes the shear modulus, ρ is the mass density and υ is Poisson’s ratio of the FGM cantilever plate. Figure 2 represents the steps required for free vibration analysis by using the MARS model.

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47

Fig. 2 Flowchart for free vibration analysis by using MARS model

5 Results and Discussions In the present study, aluminium and zirconium are considered as the two constitutes of FGM plate, where individual material properties of constitute are taken as E Al = 70 GPa, υAl = 0.25, ρAl = 2707 Kg/m3 , E Zr = 151 GPa, υ Zr = 0.3 and ρZr = 3000 Kg/m3 [50]. The stiffness and mass matrix of the FGM plate depends upon the temperature of the plate because the material properties of the plate are influenced by the temperature as shown in Fig. 3. From Fig. 3, it is found that with an increase in the temperature, elastic modulus and shear modulus of the FGM plate are decreased, while Poisson’s ratio increased with increase in temperature. The influence of temperature on the natural frequencies is determined by providing 10% degree of stochasticity in the material properties of FG plate. The finite element analysis is coupled with surrogate MARS model to achieve the better computational efficiency and lower cost without compromising the accuracy of the results. The Monte Carlo simulation required 10,000 numbers of simulations, which increases the cost and time of computational work. To mitigate this lacuna of MCS, a surrogate MARS model is employed in the present study. Figure 4 shows PDF plots of first three natural frequencies for the validation of the surrogate model with the original FE model and Monte Carlo simulation and found that the surrogate model has well fitted with the original FE model. The sample size considered for MARS model is 128 with neglecting the effect of noise. The effects of variation in temperature on the free vibration are shown in Fig. 5 by using the PDF plots. The results revealed that with an increase in temperature from 100 to 900 K, all natural frequencies decreased, due to decrement in stiffness of the plate with an increase in temperature.

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Fig. 3 Variation of the material properties across the depth of FG plate due to change in temperature (T )

A Stochastic Investigation of Effect of Temperature …

49

Fig. 4 PDF plots of first three natural frequencies for MCS and MARS with sample size (N = 128) with considering T = 300 K, p = 1

50

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Fig. 5 Effect of variation in temperature (T ) on first three natural frequencies with considering p = 1

A Stochastic Investigation of Effect of Temperature …

51

6 Conclusions The novelty of the present paper is that it employed surrogate MARS model for the stochastic free vibration analysis of FGM cantilever plate. The influence of temperature on the first three natural frequencies is determined by allowing the 10% degree of stochasticity in material properties. The material properties are found to be significantly affected by temperature. The results show that MARS model can obtain good agreement with original FE model with good accuracy. The number of simulations required is significantly reduced from 10,000 to 128; so computational time and cost are decreased significantly. It is found that temperature significantly affects the natural frequencies of functionally graded cantilever plates. Acknowledgements P. K. Karsh received financial support from the MHRD, Government of India, during this research work.

References 1. Bednarik M, Cervenka M, Groby JP, Lotton P (2018) One-dimensional propagation of longitudinal elastic waves through functionally graded materials. Int J Solids Struct. https://doi.org/ 10.1016/j.ijsolstr.2018.03.017 2. Dey S, Mukhopadhyay T, Khodaparast HH, Kerfriden P, Adhikari S (2015) Rotational and plylevel uncertainty in response of composite shallow conical shells. Compos Struct 131:594–605 3. Dey S, Mukhopadhyay T, Sahu SK, Adhikari S (2016) Effect of cutout on stochastic natural frequency of composite curved panels. Compos B Eng 105:188–202 4. Dey S, Mukhopadhyay T, Adhikari S (2018) Uncertainty quantification in laminated composites: a meta-model based approach. CRC Press, Taylor & Francis Group, Boca Raton. ISBN 9781498784450 5. Dey S, Mukhopadhyay T, Naskar S, Dey TK, Chalak HD, Adhikari S (2016) Probabilistic characterization for dynamics and stability of laminated soft core sandwich plates. J Sandwich Struct Mater. https://doi.org/10.1177/1099636217694229 6. Dey S, Mukhopadhyay T, Spickenheuer A, Gohs U, Adhikari S (2016) Uncertainty quantification in natural frequency of composite plates—an artificial neural network based approach. Adv Compos Lett 25(2):43–48 7. Dey S, Naskar S, Mukhopadhyay T, Gohs U, Spickenheuer A, Bittrich L, Adhikari S, Heinrich G (2016) Uncertain natural frequency analysis of composite plates including effect of noise—a polynomial neural network approach. Compos Struct 143:130–142 8. Mukhopadhyay T (2017) Mechanics of quasi-periodic lattices. Ph.D. thesis, Swansea University 9. Mukhopadhyay T, Adhikari S (2017) Effective in-plane elastic moduli of quasi-random spatially irregular hexagonal lattices. Int J Eng Sci 119:142–179 10. Hien TD, Noh HC (2017) Stochastic isogeometric analysis of free vibration of functionally graded plates considering material randomness. Comput Methods Appl Mech Eng 318:845–863 11. Xu Y, Qian Y, Song G (2016) Stochastic finite element method for free vibration characteristics of random FGM beams. Appl Math Model 40(23):10238–10253 12. Shenas AG, Ziaee S, Malekzadeh P (2017) Nonlinear vibration analysis of pre-twisted functionally graded microbeams in thermal environment. Thin-Walled Struct 118:87–104 13. Zghal S, Frikha A, Dammak F (2018) Free vibration analysis of carbon nanotube-reinforced functionally graded composite shell structures. Appl Math Model 53:132–155

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14. Barzegar AR, Fadaee M (2018) Thermal vibration analysis of functionally graded shallow spherical caps by introducing a decoupling analytical approach. Appl Math Model. https://doi. org/10.1016/j.apm.2018.02.018 15. Wang ZH, Wang XH, Xu GD, Cheng S, Zeng T (2016) Free vibration of two-directional functionally graded beams. Compos Struct 135:191–198 16. Rezaiee-Pajand M, Hozhabrossadati SM (2016) Analytical and numerical method for free vibration of double-axially functionally graded beams. Compos Struct 152:488–498 17. Chen D, Yang J, Kitipornchai S (2016) Free and forced vibrations of shear deformable functionally graded porous beams. Int J Mech Sci 108:14–22 18. Xue Y, Jin G, Ding H, Chen M (2018) Free vibration analysis of in-plane functionally graded plates using a refined plate theory and isogeometric approach. Compos Struct. https://doi.org/ 10.1016/j.compstruct.2018.02.076 19. Bediz B (2018) Three-dimensional vibration behavior of bi-directional functionally graded curved parallelepipeds using spectral Tchebychev approach. Compos Struct 191:100–112 20. Liu M, Cheng Y, Liu J (2015) High-order free vibration analysis of sandwich plates with both functionally graded face sheets and functionally graded flexible core. Compos B Eng 72:97–107 21. Razavi H, Babadi AF, Beni YT (2017) Free vibration analysis of functionally graded piezoelectric cylindrical nanoshell based on consistent couple stress theory. Compos Struct 160:1299–1309 22. Mukhopadhyay T, Mahata A, Dey S, Adhikari S (2016) Probabilistic analysis and design of HCP nanowires: an efficient surrogate based molecular dynamics simulation approach. J Mater Sci Technol 32(12):1345–1351 23. Mahata A, Mukhopadhyay T, Adhikari S (2016) A polynomial chaos expansion based molecular dynamics study for probabilistic strength analysis of nano-twinned copper. Mater Res Express 3:036501 24. Mukhopadhyay T, Mahata A, Adhikari S, Asle Zaeem M (2017) Effective mechanical properties of multilayer nano-heterostructures. Sci Rep 7:15818 25. Mukhopadhyay T, Adhikari S (2016) Effective in-plane elastic properties of auxetic honeycombs with spatial irregularity. Mech Mater 95:204–222 26. Karsh PK, Mukhopadhyay T, Dey S (2018) Spatial vulnerability analysis for the first ply failure strength of composite laminates including effect of delamination. Compos Struct 184:554–567 27. Mukhopadhyay T, Adhikari S, Batou A (2017) Frequency domain homogenization for the viscoelastic properties of spatially correlated quasi-periodic lattices. Int J Mech Sci. https:// doi.org/10.1016/j.ijmecsci.2017.09.004 28. Mukhopadhyay T, Adhikari S (2016) Equivalent in-plane elastic properties of irregular honeycombs: an analytical approach. Int J Solids Struct 91:169–184 29. Mukhopadhyay T, Adhikari S (2017) Stochastic mechanics of metamaterials. Compos Struct 162:85–97 30. Karsh PK, Mukhopadhyay T, Dey S (2018) Stochastic dynamic analysis of twisted functionally graded plates. Compos B Eng 147:259–278 31. Meirovitch L (1992) Dynamics and control of structures. Wiley, NY 32. Touloukian YS (1967) Thermophysical properties of high temperature solid materials. McMillan, New York 33. Mukhopadhyay T, Adhikari S (2016) Free vibration analysis of sandwich panels with randomly irregular honeycomb core. J Eng Mech 142(11):06016008 34. Mukhopadhyay T, Mahata A, Adhikari S, Asle Zaeem M (2018) Probing the shear modulus of two-dimensional multiplanar nanostructures and heterostructures. Nanoscale 10:5280–5294 35. Mukhopadhyay T, Mahata A, Adhikari S, Asle Zaeem M (2017) Effective elastic properties of two dimensional multiplanar hexagonal nano-structures. 2D Mater 4:025006 36. Dey S, Mukhopadhyay T, Adhikari S (2017) Metamodel based high-fidelity stochastic analysis of composite laminates: a concise review with critical comparative assessment. Compos Struct 171:227–250

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37. Mukhopadhyay T, Naskar S, Dey S, Adhikari S (2016) On quantifying the effect of noise in surrogate based stochastic free vibration analysis of laminated composite shallow shells. Compos Struct 140:798–805 38. Dey S, Mukhopadhyay T, Khodaparast HH, Adhikari S (2016) A response surface modelling approach for resonance driven reliability based optimization of composite shells. Periodica Polytech Civil Eng 60(1):103–111 39. Dey TK, Mukhopadhyay T, Chakrabarti A, Sharma UK (2015) Efficient lightweight design of FRP bridge deck. Proc Inst Civ Eng Struct Buildings 168(10):697–707 40. Mukhopadhyay T, Chowdhury R, Chakrabarti A (2016) Structural damage identification: a random sampling-high dimensional model representation approach. Adv Struct Eng 19(6):908–927 41. Mukhopadhyay T, Dey TK, Dey S, Chakrabarti A (2015) Optimization of fiber reinforced polymer web core bridge deck—a hybrid approach. Struct Eng Int 25(2):173–183 42. Naskar S, Mukhopadhyay T, Sriramula S, Adhikari S (2017) Stochastic natural frequency analysis of damaged thin-walled laminated composite beams with uncertainty in micromechanical properties. Compos Struct 160:312–334 43. Dey S, Mukhopadhyay T, Sahu SK, Adhikari S (2018) Stochastic dynamic stability analysis of composite curved panels subjected to non-uniform partial edge loading. Eur J Mech A Solids 67:108–122 44. Friedman JH (1991) Multivariate adaptive regression splines. Ann Stat 19(1):1–67 45. Hastie T, Tibshirani R, Friedman J (2009) Unsupervised learning. In: The elements of statistical learning. Springer, New York 46. Metya S, Mukhopadhyay T, Adhikari S, Bhattacharya G (2017) System reliability analysis of soil slopes with general slip surfaces using multivariate adaptive regression splines. Comput Geotech 87:212–228 47. Mukhopadhyay T (2017) A multivariate adaptive regression splines based damage identification methodology for web core composite bridges including the effect of noise. J Sandwich Struct Mater 1099636216682533 48. Sobol IYM (1967) On the distribution of points in a cube and the approximate evaluation of integrals. Zhurnal Vychislitel’noi Matematiki i Matematicheskoi Fiziki 7(4):784–802 49. Mukhopadhyay T, Dey TK, Chowdhury R, Chakrabarti A, Adhikari S (2015) Optimum design of FRP bridge deck: an efficient RS-HDMR based approach. Struct Multi Optim 52(3):459–477 50. Singh H, Hazarika BC, Dey S (2017) Low velocity impact responses of functionally graded plates. Procedia Eng 173:264–270

Retrofitting of a Multistoried Building with Earthquake-Resistance Design J. Bhattacharjee, Harshul Mehta, Shiv Dutt Singh Thakur and Aditya Jain

Abstract The predictable growth in economic actions during the twenty-first century is very huge in construction and in transportation. With the increase in population and globalization, there is very less land available for construction purposes; thus, the need of high-rise buildings which are capable enough to resist seismic forces is of much importance. Designing the members of such a high-rise building is being very repetitive and time-consuming, so the concepts of MACROS are widely used for design purposes and can easily eliminate these disadvantages. In this project, the structure is first analyzed by using STAAD Pro and members of the building are designed on the same. Manual calculations were compared with the STAAD Pro results. The structure, which was constructed as G+9, was required to be vertically expanded to G+13. Thereby redesigning and retrofitting measures were taken to modify the structure to withstand increased load. Keywords Design of G+9 and G+13 · Live load · Dead load · Wind load · Earthquake load · Retrofitting and repair work

1 Introduction In each part of human development, we require some structures to live in or to get certain facilities we require. It is a building structures as well as other allied services, so as to satisfy the fundamental reason for what it was made for. Here comes the part of structural designing and all the more decisively the part of examination of the structure. There are numerous established techniques to take care of outline issue, and J. Bhattacharjee (B) · H. Mehta · S. D. S. Thakur · A. Jain Department of Civil Engineering, Amity University, Noida, UP, India e-mail: [email protected] H. Mehta e-mail: [email protected] S. D. S. Thakur e-mail: [email protected] © Springer Nature Singapore Pte Ltd. 2020 S. Adhikari et al. (eds.), Advances in Structural Engineering and Rehabilitation, Lecture Notes in Civil Engineering 38, https://doi.org/10.1007/978-981-13-7615-3_4

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with time, new programmings additionally becoming possibly the most important factor. Here in this study, software program named STAAD Pro has been utilized. These issues have been comprehended utilizing the fundamental idea of stacking, investigation, according to IS code. These essential systems might be discovered valuable for further investigation of the study. Among the characteristic perils, seismic tremors have the potential for making the best harms designed structures. India has some of the world’s most prominent seismic tremors in the most recent century. Actually, more than 50% range in the nation is viewed as a potential threat to harming seismic tremors. The north-eastern area of the nation and in addition the whole Himalayan belt is powerless to incredible tremors of greatness more than 8.0.

2 Aim of the Study Experience in past earthquakes has demonstrated that many common buildings and typical methods of construction lack basic resistance to earthquake forces. In this study, software design of the structural elements of a multistoried building of G+9 is carried out and making it to G+13 on functional requirement and find out the difference in the amount of steel and concrete used and measured for retrofitting work done. Studying the effect of seismic force on structure and methods to make it earthquake-resistant software required used are: (i) Staad pro version V8i (ii) AutoCAD The building is a residential building of: G+9 stories. (i) Shape of the building: Rectangular (ii) Type of construction: R.C.C framed structure (iii) Type of walls: Brick wall.

3 Geometric Details • • • • • • • •

Ground Floor Height—3.5 m Floor Height—3.5 m Height of plinth—1.2 m Thickness of Slab—150 mm Thickness of Wall—230 mm Column dimensions—400 × 400 mm Floor beams—250 × 400 mm Stairs riser = 150 mm Tread = 250 mm (Figs. 1 and 2).

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Fig. 1 Plan

Fig. 2 STAAD modeling

4 Load Calculations

Dead load Description

Dimension (mm)

Unit weight of material used (kN/m3 )

Dead load (kN/m)

1.

Columns

400 × 400

25

4

2.

Floor beams

250 × 400

25

2.5

3.

Terrace and ground beams

250 × 350

25

2.1875

4.

Slab

150

25

3.75

5.

Brick wall

230

25

16.795

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Terrace (L.L + D.L)

Typical (L.L + D.L)

Self (150 mm)

3.75 + 0

3.75 + 0

Waterproofing

2+0

0+0

Flooring

1+0

1+0

Live load

0 + 1.5

0+4

STAAD calculations Dead load

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Live load

Wind load

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DESIGN OF G+13

5 Proposed Structure • • • • • • • • • • • • •

Residential building No. of storeys: G+13 (by vertically expanding the structure) Shape of the building: Rectangular Construction Material: R.C.C frame structure Type of walls: Brick wall Ground Floor—3.5 m Floor Height—3.5 m Height of plinth—1.2 m Thickness of Slab—150 mm. Thickness of Wall—230 mm Column dimensions—600 × 450 mm (assumed) Floor beams—350 × 450 mm (assumed) Stairs: Riser = 150 mm; Tread = 250 mm.

6 Findings of the Analysis/Design From the analysis, it was found that the structure can be vertically extended by four floors, for which column as well as the foundation require to be retrofitted. In order to increase the load-carrying capacity and the flexure stiffness of the structure, certain columns of the building were recommended for retrofitting. The original size of the column was 400 × 400 and beam of 250 × 400 mm, which was proposed to be changed to 600 × 450 mm and beam size increased to 350 × 450 mm. After modeling them on STADD Pro, the whole structure with the increased load as well as the foundation was found to be safe. Now the method of retrofitting suggested is brought out below.

7 Column/Beam Retrofitting Columns/beams are one of the most important and crucial parts of the building. Particularly if the column fails, it can lead to failure of the whole structure. No doubt beams also play an important role, but most of the crucial members in the building are the columns. The seismic analysis is based on the principle of strong columnweak beam, which means that the column should be much stronger as compared to the beam. Columns are needed to increase the deformation capacity, increase flexure

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and strength, strengthen the region of faulty spacing. The various retrofit schemes suggested are described as follows: Concrete jacketing: In this method, additional layer of concrete is used along with the additional longitudinal bars and ties. It is used to increase strength, shear, and ductility of the column. Stiffness of the column depends on the size of jacketing. Circular jacketing has been found much more effective as compared to other ones. Advantages of retrofitting by jacketing are as follows: it is less costly, local labor can be employed, and it is less time-consuming also. However, disadvantages are increase in the size of the member, and drilling of holes in existing structure is to be carried out. Ties are generally provided to increase the shear capacity. Large numbers of methods are available to provide jacketing. Proper method is selected based on the dimension. However, if the longitudinal bars are provided only along the side, then they are not continued throughout. Two ties are generally used instead of one. The angle of tie is generally kept as 135° with enough extension at the end. If the thickness is small, concrete is generally preferred. In order to ensure the proper bonding between the old and the new material, surface preparation is done. Surface can be prepared by rubbing with wire brush or by various chemicals. Dowel bars are provided in order to form a good bond. They are generally provided at the spacing of 300–500 mm. Dowel bars are joined by the epoxy. The length of the dowel bar depends on the strength of the existing concrete and the epoxy. Based on the strength of concrete and epoxy, length of the dowel bar is decided. The main disadvantage of dowel bar is that it forms plastic hinges under dynamic loading. Such things can be avoided by covering the jacketing all around the column. Minimum specifications of concrete jacketing are as follows: • Strength of new material should be higher than old one, and its compressive strength should be at least 5 MPA greater than old one; • In case no longitudinal bars are required for flexure, min 12-mm-diameter bars should be provided with 8 mm ties; • Minimum thickness should not be less than 100 mm; • Minimum tie diameter should be 8 mm and anchored at 135°; • Center-to-center spacing should not be greater than 200 mm, preferably it should not be less than the thickness of jacketing as shown in Fig. 1.

8 Conclusion Feasibility study was made, and various non-destructive tests were carried out on the building in order to determine the health of the building. After performing various tests, it was observed that the building is in good condition and there is the room for further extension. Further, Staad Pro analysis was performed for the same building in order to determine whether it can take further loads or not for two additional floors. After analysis, it was found out the there are certain columns that are not capa-

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ble of taking the extra load due to increase in floor loads. Hence, after redesigning with increased loads, certain column’s dimension increased at bottom level. Further, beam dimension was changed. In the coming years, the work in the field of earthquake-resistant design is very important to have safe structures which can take the effect of earthquake with minimum damage. In our project, after applying all load combinations, it has been concluded that the effect of earthquake comes out to be more severe even though the maximum wind load is acting (with a wind intensity of 39 m/s). Earthquake load is applied for different combinations, and the worst case is considered for design. Members were analyzed and designed in the STAAD Pro. Also the design is done by two different ways in STAAD Pro: one is simple design method, and the other is interaction concrete design. Manual computation of design of different critical members is done, and results of the critical members by STAAD Pro are checked. The results shown by STAAD Pro and the manual computation of design are almost same. All the checks as per IS 456:2000 were performed. All the members are also designed for seismic forces, and reinforcement for the same is provided as per IS 13920-1993 (ductile detailing of reinforced concrete structures subjected to seismic forces). Ductility in seismic design has a great importance.

Biological Methods to Achieve Self-healing in Concrete Sunita Bansal , Raj Kumar Tamang , Prince Bansal and Pratik Bhurtel

Abstract Concrete structures experience cracks due to faulty design, drying shrinkage, thermal contraction effects, etc. A continuous network of cracks escalates degradation due to increased permeability and exposure of embedded rebars to ambient air. Contemporary sustainability issues of construction sector demand durability of materials and structure for longer service life. Incorporating self-healing mechanism of cracks can be made to flourish at initial stages under certain controlled conditions. The objective of this paper is to explore the laboratory-proven biological techniques to induce self-healing in concrete in terms of ease of preparation, process and cost. The effect on concrete characteristics like compressive and flexural strength, permeability of water, corrosion resistance of the reinforcement bars are studied and presented in this paper. Keywords Self-healing concrete · Cracks · Biological method · Bacteria · Microcapsules

1 Introduction Concrete is the most abundant, sustainable and versatile material for construction but being quasi-brittle, and it is liable to cracks due to tension or shear. Concrete used in buildings, bridges, dams, pavements, etc., is reinforced with steel to have S. Bansal (B) · R. K. Tamang · P. Bansal · P. Bhurtel Department of Civil Engineering, Faculty of Engineering and Technology, Manav Rachna International Institute of Research and Studies, Faridabad, India e-mail: [email protected] R. K. Tamang e-mail: [email protected] P. Bansal e-mail: [email protected] P. Bhurtel e-mail: [email protected] © Springer Nature Singapore Pte Ltd. 2020 S. Adhikari et al. (eds.), Advances in Structural Engineering and Rehabilitation, Lecture Notes in Civil Engineering 38, https://doi.org/10.1007/978-981-13-7615-3_5

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adequate compressive and tensile strength, but minute cracks may appear even when the structure is safe. Cracks may occur in concrete in all developmental stages due to reasons like poor workmanship, improper mix. Generally, these cracks are smaller in width during the initial stages and may not affect the stability of the structure but as the structure is subjected to further stress, these cracks may increase in width and length and affect the structural integrity of concrete. Furthermore, these cracks serve as pathways for water and other harmful chemicals that may end up corroding the reinforcements when exposed to ambient air, hence affecting the stability of the structure. As concrete repair is not easy and requires a lot of money and manpower, it is best to avoid, mitigate or arrest cracks in the initial stages. In this way, there is a need to find an economical method for recuperating cracks which include less cost and eliminate the need of manual intercession. Self-healing is a developing idea of conveying high calibre materials along with the capacity to recuperate cracks, and it has gotten much consideration in the past decade for application in building structures. A viable self-healing component might have the capacity to decrease repair and upkeep works significantly. In the most recent decades, a few explores and studies were pointed at researching the physical/chemical/mechanical conduct of cementitious materials containing “engineered” self-healing components. These can be broadly categorised into five groups—encapsulation of chemicals, addition of mineral admixtures, encapsulation of bacteria or biological approach, intrinsic self-healing with self-controlled tight crack width and chemicals in glass tubes [1]. Chemical encapsulation makes the use of chemicals embedded in microcapsules which in turn can be embedded in the concrete mixture. The opening of capsules is triggered either by stress or moisture and the chemicals which are then released react with the concrete materials, thereby sealing the cracks. Another method is the use of chemical admixtures in concrete, which increase the self-healing process in concrete by reducing the water permeability of concrete after damage. The biological approach makes the use of Bacillus bacteria. Bacterial encapsulation requires the usage of bacteria in microcapsules along with a chemical precursor that are mixed in concrete during the mixing process. These bacteria are usually carbonate producing bacteria which can help in inducing the precipitation of calcium carbonate. In this method, dormant bacteria are packed in porous expanded clay particles and are embedded in the matrix. When they come into contact with a catalyst (water), they produce limestone as a precipitate which clogs the cracks. In chemical approach, polyurea or polyurethane (PU) microcapsules with an aqueous sodium silicate (NaSiO3 ) core are implanted in the concrete matrix [2]. It has been observed that self-healing property of concrete can be increased by small thin glasses which release chemicals when they are broken (because of stress) [3]. Thus, the use of chemicals in glass tubes has also been explored. By increasing tensile stress on the structure, intrinsic self-healing can be induced that can tighten the cracks, hence reducing the width of cracks. This process needs prolonged exposure to moisture so that autogenous healing of cracks can occur [4]. This paper aims to highlight a certain portion of existing literature and discuss some methods in the biological encapsulation approaches to give a clear view. The

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discussion is conducted in the light of the sample preparation, procedure, efficiency, accessibility, cost efficiency, workability and other important aspects.

2 Biological Approach to Self-healing Limestone is a material that can be used to close and seal the crack. This limestone can be produced by a certain type of bacteria that acts on a material called ‘calcium lactate’ and oxygen to produce calcium carbonate (limestone). Packing concrete with calcium lactate will not affect the settling time of concrete mix. The bacteria that have been used belong to the genus Bacillus which has the capability to convert calcium lactate into calcium carbonate which leads to sealing the cracks in the concrete. However, in order to preserve the bacterial viability in a dormant state, they need to be encapsulated along with some nutrients. The formation of cracks leads to percolation of water in the capsules leading to revival of the dormant bacteria. The bacterial metabolism results in the production of calcium carbonate and healing of the cracks. Once the cracks are sealed, water cannot penetrate and the bacteria return to the dormant state. The bacterial capsules may spherical or cylindrical shape- or spore-based approach may be adopted [5]. The self-healing agent can be dormant for a long time until activated. The bacteria, nutrients and calcium lactate together are called ‘self-healing agents’. These agents are embedded in capsules, and these capsules will be embedded in the concrete mix. Bashir et al. [6]used a binder or filler material (bacteria) with calcium lactate to develop self-healing in concrete. They performed the comparison on compressive strength, split tensile strength and flexural strength in between conventional concrete and three self-healing concrete samples that had three different bacteria; Bacillus subtilis, Bacillus sphaericus and Bacillus pasteurii. The authors suggested that the self-healing concrete is advantageous in country like India where structure failure by climate change is a major problem. Palin et al. [7] in their journal used a self-healing cement paste incorporated with a bacterium-based beads to be functionalized in a low-temperature marine atmosphere. They found that the bacterium-based cement composites are capable of reducing the permeability cracks of 0.4–0.6 mm width by 93–95% after 58 days of immersion in artificial marine water at 8 °C. Bang et al. [8] in their research induced CaCO3 precipitation by immobilizing Bacillus pasteurii with the help of polyurethane. This immobilization resulted in higher rates of precipitation and higher ammonia production as well as increased elastic modulus, tensile strength and compressive strength in concrete specimens. They used PU strips of diameter; 10 mm and length; 50 mm into a crack of depth of 25.4 mm and width 3.18 mm inside the concrete. This was possible because the volume of polyurethane foam gets reduced by an amount of about 36% by air drying, but it maintains the elastic property. SEM analysis was also done to evaluate the pattern of calcite precipitation and ammonia production. Rabindranath et al. [9] solved the problem of low durability of structures that are exposed to abrasive environment by developing a bio-concrete. They prepared a

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bacterial solution of Bacillus pasteurii and mixed with other constituents of concrete and placed in moulds. Those cubes were then subjected to compressive strength test and flexural strength test at 7 and 28 days. The bio-concrete is found to have higher compressive and flexural strength and suggested as an alternative technique for replacing OPC along with its dangerous effect on atmosphere. Jing and Wang [10] have proposed the new technique in self-healing concrete of protecting the bacterial spores by the use of low alkali content cementitious substance. The bacterial spores get crushed and squeezed due to high alkaline environment, so that an immobilizing bacteria or the low pH content is preferred for self-healing in concrete. Therefore, they especially used calcium sulpho-aluminate cement, which is low alkali and fast hardening cementitious material, with 20% silica fumes which act as preservative carrier for the bacteria. They examined that the crack of width up to 417 µm can be healed totally in 28 days. Dhaarani and Prakash [11] developed a durable concrete by the use of bacteria and high-volume fly ash in the replacement of ordinary cement so as to reduce the maintenance work and the carbon dioxide emission, respectively. The main aim of using HVFA is also to increase the durability, strength as well as to reduce the permeability, alkali–silica reactivity, heat of hydration, efflorescence, etc. For this research, they have inoculated the bacteria inside the laminar air flow chamber and stored in an incubator. After that, they mixed it with other constituents so in a ratio to meet M40 grade concrete. The casted concrete specimen is then tested for durability and strength and which is expected to come positive. Ponraj et al. [12] reviewed the strength, permeability, durability, recycling of bio-concrete and its impact on human health. Based on his literature survey, the increment in the durability of bio-concrete depends upon the type of surrounding atmosphere but more durable than the conventional concrete. The strength also gets enhanced when aerobic micro-organisms are used as self-healing agent. The use of bacteria made the concrete porous which results in an increase in permeability. Also, the waste concrete aggregate of this bio-concrete can be recycled as a ground filling material of for highways, runways and for new concrete too. The pathogenic bacteria type used in concrete spreads diseases to the human and animal. Thus, an ureolytic, non-pathogenic bacteria like Bacillus pasteurii, is being advisable according to this paper. Plain et al. [7] in their article proposed an approach of achieving self-healing in concrete structures that are exposed to low temperature basically in marine environments. They experimented that healing capacity in an artificial seawater at 8 °C and concluded that the ability of crack clogging is higher for larger width. The autogenous healing capacity is more in marine environment in which healing is accredited by autogenous precipitation, autonomous bead swelling, magnesium-based mineral precipitation and bacteria-induced calcium-based mineral precipitation. They figured out that the compressive strength is lower than the normal specimen although it displayed eminent crack healing ability. However, the compressive strength of these bacteria-based cement composites can be increased by the addition of polymer of high compressive strength.

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Vijay et al. [13] in their review paper mentioned about the use of various bacteria inside the concrete with different techniques such as encapsulation of bacteria, direct addition of bacteria in order to heal the crack developed due to various reasons.The researcher also refers to the effects of this bio concrete on the various characteristic properties of concrete viz; compressive strength, chloride ion permeability and water penetration. According to their review, the concrete with Bacillus sp. CT-5 in a concentration of 5 × 107 cells/mm3 gives rise to higher compressive strength of more than 40%. The precipitation of calcite crystals made the bacterial pores filled with these white crystals resulting in the reduction of porosity and water permeability. They have also concluded that the average number of chloride ions passed through the concrete containing bacteria is about 12% less than that of without bacteria. This protects reinforcement from corrosion and makes structures durable. Luo et al. [14] presented the autogenous crack repairing bacteria-based concrete with the various factors influencing it in their paper. By analysing the precipitation of calcium carbonate at the surface of cracks through X-ray diffraction (XRD) and scanning electron microscope (SEM), they concluded that the difficulty in crack repairing arises when the crack width is bit large specifically greater than 0.8 mm. However, the best and precise crack healing is obtained by curing that cracked concrete inside water. When the crack width is prolonged, the survival of bacteria inside the cementitious matrix gets reduced [14]. Khaliq and Ehsan [15] gave an idea of healing crack in concrete by direct introjection or by the use of various carrier compounds such as lightweight aggregates (LWAs) and graphite nano-platelets (GNP) together with the organic precursor, calcium lactate. The carriers are used to increase the feasibility of bacteria as well as the efficiency of crack healing. They examined that the concrete samples incorporated with GNP show best healing ability with about 10% increase in compressive strength while the specimens with LWA displayed higher compressive strength than others but lower healing than GNP. Also, they added that the sample prepared by direct incorporation did not give the good result of crack healing. The strength of indirectly added bacteria sample can be increased by making small size of particle which gives proper compaction and spreads the bacteria throughout the mixture.

3 Materials and Methods 3.1 Sample Preparation The various methods that have been explored using this approach are as follows. The types of bacteria that can be used are the ones which can thrive in alkaline conditions because the pH of cement and water is around 13. Bacillus alkalinitrulicus, an alkali-resistant soil bacterium, psychrophilic bacterium and Bacillus sphaericus can be used. These are found under extreme conditions where pH values range between 9 and 13. The several types of bacteria that have been explored to be used

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in self-healing concrete are [16]—Bacillus halodurans, Bacillus pasteurii, Bacillus sphaericus, Bacillus pseudofirmus, Bacillus subtilis, Escherichia coli, Bacillus cohnii, etc. The psychrophilic bacterium, in the form of spores, is mixed in the concrete matrix. Spores are inactive cells with high survival rate. They survive in adverse conditions as well and become active when they come into contact with water. When water supply stops, the spores close themselves. When cracks appear in the self-healing concrete, the added capsules rip out. As a result, seeped water flows inside and the bacteria get activated. The bacteria, feeding on the nutrients and calcium lactate, produce an insoluble white calcium carbonate as the final product. The cracks or voids are filled by the produced limestone, and there would not be any possibility for ingress of water. The bacteria become inactive when the water supply is prevented and the spores will close up. The reactions that take place are [17]: 5CO2 + 5Ca(OH)2 → CaCO3 + 5H2 O Carbon Dioxide + Calcium Hydroxide → Limestone + Water Ca(C3 H5 O2 )2 + 7O2 → CaCO3 + 5CO2 + 5H2 O Calcium Lactate + Oxygen → Limestone + Carbon Dioxide + Water i. In porous clay particles, the bacterial spores of calcium lactate yeast extract are encapsulated up to 4 mm in size [4]. ii. In 40-mm-long glass tubes with 40 mm diameter, immobilized bacteria in silica gel and polyurethane are embedded. A mortar crack allows conversion of urea into ammonia and carbonate due to the discharge of bacteria upon glass tube rupturing. As a result, calcium carbonate is precipitated on the bacterial cell wall and surrounding medium under this high carbonate environment [4]. iii. The healing agent can be encapsulated inside coated hollow plant fibres in order to reduce the suction effect exerted by the closed ends of the cylindrical capsules [18]. When cracks spread in the concrete mix, the fibre bundles begin to come apart into its component layers. Consequently, the healing agent spreads from the fragmented fibre bundles into the damaged areas where it reacts accordingly.

3.2 Methodology for Analysis of Concrete Types A. Mixing two Types of concrete Two different types of concrete have to be made. Type 1: Presently used concrete. Type 2: Concrete that heals itself. This concrete is different from the other concrete as it contains a healing agent.

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Fig. 1 Breaking the concrete disc, by impact load [17]

B. Breaking the Concrete Before testing the discs, they have to be broken and glued as shown in Fig. 1. If we do not break the discs before testing them, it will probably take years before leakage cracks appear. By breaking the concrete, the bacteria will be activated immediately, so we will have our results sooner. When the concrete is broken, the separate parts are glued together. It will take 2 days for the glue to dry. C. Measuring the Leakage/Water Percolation Test As in Fig. 2, an amount of 5 L water is placed in a bucket of Ø18 cm comprising the concrete disc. The amount of water percolating through disc in 1 h period is measured. D. Placing Concrete in a Canal Section When all discs have been made and the amount of leakage has been measured, the discs have to be put in a canal as shown in Fig. 3. The heavy weight of the discs will ensure that the discs will not wash away with the stream. It is not necessary to attach the discs to the canal. E. Measuring Leakage After Curing Period After a period of three months (twelve weeks), we will remove the discs from the water. By this time, the self-healing bacteria should have done their work, filling the cracks with lime. We will repeat the measurement method (see the third step) and compare the results. Once we get the results, the cost has to be estimated, and the pros and cons of using the bacterial method for achieving self-healing concrete can be inferred.

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Fig. 2 Measuring the leakage through the crack [17]

Fig. 3 Placement of disc in canal section [17]

4 Conclusion There was nearly no significant loss in compressive strength of concrete with the biological agents, and flexural strength is shown to increase in bacterial concrete. The bacterial concrete is more economical as compared to repaired conventional concrete beside the ease of casting. The permeability of concrete with bacteria embedded in it has no measureable permeability. The decrease in permeability will decrease the amount of water entering the matrix, thereby preventing corrosion to some extent. In concrete with biochemical agents (a mixture of bacteria and calcium lactate), the agents consume oxygen, thereby acting as a diffusive barrier to the steel reinforcements. Therefore, a decrease in corrosion can be seen.

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Acknowledgements The authors thank Accendere Knowledge Management Services for giving valuable suggestion and inputs for writing the paper.

References 1. Approaches, biomimetic design, cementitious composites, and liquid-based healing agents. Self-healing of concrete—a new technology for a more sustainable future, 6–9. http://www. swieet2007.org.uk/files/SelfHealingConcrete 2. Tang W, Omid K, Hongzhi C (2015) Robust evaluation of self-healing efficiency in cementitious materials—a review. Constr Build Mater 81:33–47. https://doi.org/10.1016/j.conbuildmat. 2015.02.054 3. Li VC, Emily H (2012) Robust self-healing concrete for sustainable infrastructure. J Adv Concr Technol 10(6):207–218. https://doi.org/10.3151/jact.10.207 4. Tittelboom KV, Nele DB (2013) Self-healing in cementitious materials—a review. Materials 2182–2217. https://doi.org/10.3390/ma6062182 5. Talaiekhozan A, Ali K, Arezo S, Ramin A, Abd M, Mohamad AF (2014) A review of selfhealing concrete research development. J Environ Treat Tech 2(1):1–11 6. Bashir J, Kathwari I, Tiwary A, Singh K (2016) Bio concrete—the self-healing concrete. Indian J Sci Technol 1–5. https://doi.org/10.17485/ijst/2016/v9i47/105252 7. Palin D, Virginie W, Henk MJ (2017) A bacteria-based self-healing cementitious composite for application in low-temperature marine environments. Biomimetics 2(3):13. https://doi.org/ 10.3390/biomimetics2030013 8. Bang SS, Galinat JK, Ramakrishnan V (2001) Calcite precipitation induced by polyurethaneimmobilized Bacillus pasteurii. Enzym Microb Technol 28(4–5):404–409. https://doi.org/10. 1016/S0141-0229(00)00348-3 9. Ravindranatha, Kannan N, Likhit ML (2014) Self-healing material bacterial concrete. IJRET 2319–2322 10. Xu J, Wang X (2018) Self-healing of concrete cracks by use of bacteria-containing low alkali cementitious material. Constr Build Mater 167:1–14. https://doi.org/10.1016/j.conbuildmat. 2018.02.020 11. Dhaarani M, Prakash K (2014) Durability study on hvfa based bacterial concrete—a literature study. Int J Struct Civ Eng Res 3(4) 12. Ponraj M, Amirreza T, Rosli MZ, Mohammad I, Muhd Z, Abd M, Ali K, Hesam K (2015) Bioconcrete strength, durability, permeability, recycling and effects on human health: a review, 1–9. https://doi.org/10.15224/978-1-63248-062-0-28. 13. Vijay K, Meena M, Shirish VD (2017) Bacteria based self healing concrete—a review. Constr Build Mater 152:1008–1014. https://doi.org/10.1016/j.conbuildmat.2017.07.040 14. Luo M, Chun XQ, Rui YL (2015) Factors affecting crack repairing capacity of bacteria-based self-healing concrete. Constr Build Mater 87:1–7. https://doi.org/10.1016/j.conbuildmat.2015. 03.117 15. Khaliq W, Muhammad BE (2016) Crack healing in concrete using various bio influenced selfhealing techniques. Constr Build Mater 102:349–57. https://doi.org/10.1016/j.conbuildmat. 2015.11.006 16. Soundharya S (2014) Study on the effect of calcite-precipitating bacteria on self-healing mechanism of concrete. IJERMT 1(4):202–208 17. Ruben B, Jeroen G, Stijn J, Roel O (2012) A concrete solution for a concrete problem, 0–22. https://doi.org/10.1201/b10552-117 18. Liu H, Qian S, Van de Kuilen JW, Gard WF, Rooij MR, Schlangen E, Ursem WNJ (2009) Self-healing of concrete cracks using hollow plant fibres. In: Self-healing materials, Chicago 19. Rooij MR, Qian S, Liu H, Gard WF (2008) Using natural wood fibers to self heal concrete. In: Concrete repair, rehabilitation and retrofitting. Cape Town

Finite Element Analysis of Profiled Deck Composite Slab Using ANSYS Aniket A. Shirgaonkar, Yogesh D. Patil and Hemant S. Patil

Abstract Profiled deck composite slab is very common to use in construction, and the full-scale laboratory test on profiled deck composite slab is very expensive and time-consuming. This paper describes a finite element analysis of profiled deck composite slab using ANSYS. The main objective is to understand the deflection as well as slip characteristics of composite slab. For this study, simply supported slab is considered with variation of three parameters: the type of profiled deck sheet, concrete depth, and thickness of sheet. It has been observed that concrete depth and type of profiled deck sheet play a major role in load carrying capacity. Keywords Composite slab · ANSYS · Finite element analysis · Deflection · Slip

1 Introduction The virtue of utilizing profiled deck sheet in composite floor has been recognized for lighter, simpler, faster, and economical construction. Composite floor consists of concrete, profiled deck sheet, shear transferring devices (shear connector, embossments, and indentations), and light mesh reinforcement [1] (Fig. 1). Here, profiled deck sheet serves two major purposes: it acts as formwork during construction stage and as main tension reinforcement after hardening of concrete. For achieving full composite action of concrete and profiled deck sheet, mechanical interlocking in the form of shear connector/embossment/indentations is much needed [2]. Light mesh reinforcement is used for taking care of shrinkage and temperature effect. Nowadays, light mesh reinforcement is replaced by high strength fibers [3]. In 1938, profiled deck sheet was first used in the USA but only as a permanent formwork. In 1960, profiled deck sheet with improved shear bond with the help of

A. A. Shirgaonkar (B) · Y. D. Patil · H. S. Patil S V National Institute of Technology, Surat, India e-mail: [email protected]

© Springer Nature Singapore Pte Ltd. 2020 S. Adhikari et al. (eds.), Advances in Structural Engineering and Rehabilitation, Lecture Notes in Civil Engineering 38, https://doi.org/10.1007/978-981-13-7615-3_6

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Fig. 1 Composite floor details

Fig. 2 Details of bending test

embossment was presented, and very first time it is actually used as main tension reinforcement [2]. A profiled deck composite slab at ultimate limit state in bending is subjected to three major failure modes [4]. The first mode of failure is flexural failure which occurs in long and slender slab (section 1-1), second mode of failure is vertical shear failure (section 2-2) which occurs due to high concentrated loads near the supports, and third mode of failure is horizontal shear failure (section 3-3) which is the most common type of failure in composite slab [2] (Fig. 2). The four-point bending test is carried out to initiate the longitudinal shear failure, and this failure is determined by longitudinal slip between concrete and profiled deck sheet. The test results are used to determine the shear bond parameters [5–8] (Fig. 2). These shear bond parameters can be determined by two classical calculation methods: partial shear connection method and m-k method. The most standard codes use these methods to determine longitudinal shear strength of profiled deck composite slab models turned into a key part for some new improvements as they made a strong framework to test numerous arrangements ahead of time.

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2 Finite Element Model To study the characteristics of composite slab under the four-point loading, finite element method is one of the capable methods [8–11]. Totally twenty-seven models were prepared in solid works software to study the behavior of composite slab. Concrete height, thickness of profiled deck sheet, and type of profiled deck sheet are the parameters chosen for the analysis. ANSYS Workbench program is used for the finite element analysis. In ANSYS Workbench, nonlinear behavior of the model is analyzed by Newton-Raphson method.

2.1 Model Description Since the modeling of composite slab is time-consuming in ANSYS environment, solid works 3D drawing software is used and these drawings are imported to ANSYS Workbench. Totally twenty-seven models are prepared for analysis with an identical span of 2700 mm. Three different types of profiled deck sheets are considered in the analysis (Fig. 3). Three different types of thicknesses 0.8, 1.0, and 1.2 mm and three different depths of concrete 100, 120, and 140 mm are chosen for analysis; with these three parameters, all possible combinations are made. Appropriate material properties are assigned to the model which are listed in Tables 1, 2 and 3.

Fig. 3 Geometric shapes and dimensions (all dimensions are in mm) of the profiled steel sheet, a without stiffener; b with V-type stiffener at flange; c with rectangular type stiffener at flange Table 1 Material properties for concrete

Young’s modulus

25,000 MPa

Bulk modulus

13,021 MPa

Shear modulus

10,593 MPa

Maximum tensile pressure

3.5 MPa

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Table 2 Multilinear isotropic hardening properties for concrete Plastic strain

Stress (MPa)

0

0

0.0003

7.33

0.0006

14.76

0.0012

22.05

0.0018

24.86

0.002

25

Table 3 Material properties for profiled deck sheet Density

7850 Cg/m3

Young’s modulus

2e + 05 Pa

Bulk modulus

1.6667e + 11 Pa

Shear modulus

7.6923e + 10 Pa

Bilinear isotropic hardening properties for profiled deck sheet Yield strength

250 MPa

Tangent modulus

1450 MPa

Fig. 4 Meshing of composite slab (20 mm)

Most important part in finite element analysis is discretization of model. After developing the model, the first step is meshing. It means dividing the model into number of finite elements. There are many methods available in ANSYS WB environment for meshing; we choose meshing by sizing method, and 20 mm mesh size is selected (Fig. 4). For composite slab, critical parameter is the connection between concrete and profiled deck sheet. To simulate the interaction between concrete and profiled deck sheet, frictional connection with frictional coefficient 0.5 is opted [5]. Simply supported condition is taken for analysis, for that one end of deck slab is assigned with hinged support and another end is assigned with roller support, incremental load of

Finite Element Analysis of Profiled Deck …

77

Fig. 5 Deflection counters (composite slab without stiffener)

100 kN is applied to model through loading arrangements which are at distance of 450 mm (l/6) from both the ends.

3 Results The parametric study is conducted on profiled deck composite slab, type of profiled deck sheet, depth of concrete topping and sheet thickness were the parameters selected for finite element analysis, total deflecion at mid span and slip at hinged support are observed. Following are the results obtained by finite element analysis of composite slab. Figure 5 shows the deflection counters of composite slab without stiffener. Figures 6 and 7 show the slip and vertical separation of concrete, in similar manner for all the 27 models, results are obtained and listed in Table 4 (Figs. 8, 9, 10, 11, 12, 13, 14 and 15).

Fig. 6 Slip (composite slab without stiffener)

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Fig. 7 Vertical separation of concrete and profiled deck sheet Table 4 Results Sheet thickness (mm)

Concrete slab thickness (mm)

Profiled sheet with V-type intermediate stiffener

Profiled sheet with rectangular type intermediate stiffener

Profiled sheet without stiffener

Deflection Slip (mm) (mm)

Deflection Slip (mm) (mm)

Deflection Slip (mm) (mm)

0.8

100

18.737

3.104

20.585

3.316

22.105

3.535

0.8

120

12.434

2.381

13.166

2.139

14.873

2.798

0.8

140

10.742

2.318

9.131

1.965

10.298

2.225

1

100

18.412

3.052

19.489

3.256

21.531

3.447

1

120

12.262

2.358

12.246

2.081

14.538

2.731

1

140

10.557

2.277

8.198

1.912

10.106

2.174

1.2

100

18.071

3.001

18.945

3.155

21.128

3.383

1.2

120

12.007

2.326

11.155

2.012

14.328

2.692

1.2

140

10.391

2.239

7.156

1.815

9.983

2.157

Fig. 8 Comparison between deflections with respect to sheet thickness for profiled deck sheet with V-type stiffener

20 15 100mm

10

120mm

5

140mm

0 0.8mm

Sheet Thickness

1mm

1.2mm

Finite Element Analysis of Profiled Deck …

79

4 3 2

100mm 120mm 140mm

1 0 0.8mm

1mm

1.2mm

Sheet Thickness Fig. 9 Comparison between slip with respect to sheet thickness for profiled deck sheet with V-type stiffener 25 20 15

100mm

10

120mm

5

140mm

0 0.8mm

1mm

1.2mm

Sheet Thickness Fig. 10 Comparison between deflections with respect to sheet thickness for profiled deck sheet with rectangular type stiffener 4 3 2

100mm

1

120mm 140mm

0 0.8mm

1mm

1.2mm

Sheet Thickness Fig. 11 Comparison between slip with respect to sheet thickness for profiled deck sheet with rectangular type stiffener

4 Conclusion Twenty-seven full-scale composite slabs were analyzed using ANSYS as finite element tool. The analysis showed differences between the slabs with and without intermediate stiffeners, as well, the different thickness of slab, concrete. The loss of interaction between the steel sheet and the concrete occurred gradually in the slabs without any detrimental effect on the performance of the slabs. The failure mechanisms of the full-scale slabs were observed as follows: first yield of the bottom flange

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100mm

10

120mm

5

140mm

0

0.8mm

1mm

1.2mm

Sheet Thickness Fig. 12 Comparison between deflections with respect to sheet thickness for profiled deck sheet without stiffener 4 3

100mm

2

120mm

1

140mm

0 0.8mm

1mm

1.2mm

Sheet Thickness Fig. 13 Comparison between slip with respect to sheet thickness for profiled deck sheet without stiffener 23 22

0.8, 22.105

1, 21.531

21

1.2, 21.128

0.8, 20.585 20

1, 19.489 19

1.2, 18.945

0.8, 18.737

1, 18.412

18

1.2, 18.071

17 0.7

0.8

0.9

1

1.1

1.2

Slab Thickness Profiled sheet with V-type intermediate stiffener Profiled sheet with Rectangular type intermediate stiffener

Profiled sheet without stiffner

Fig. 14 Effect of type of profiled sheet used on deflection

1.3

Finite Element Analysis of Profiled Deck …

81

4

0.8, 3.535 0.8, 3.316

3.5

1, 3.447 1, 3.256

1.2, 3.383 1.2, 3.155 1.2, 3.001

0.8, 3.104 1, 3.052

3

2.5 2

0.7

0.8

0.9

1

1.1

1.2

1.3

Sheet Thickness

Profiled sheet with V-type intermediate stiffener Profiled sheet with Rectangular type intermediate stiffener Profiled sheet without stiffner

Fig. 15 Effect of type of profiled sheet used on slip

of the deck, concrete cracking due to differential strains in the deck and concrete, the attainment of maximum longitudinal shear resistance of the shear span, and excessive slip of the concrete over the profiled sheet. The main conclusions from analysis of composite slabs with profiled steel sheeting under static loading are as follows: • Composite slabs normally fail as a result of a critical loss of shear bond between the steel decking and concrete; when the slab failed by shear bond, the concrete slipped along the shear span. • The increase in depth of concrete slab reduces deflection significantly (33.63–42.66%); for 120 mm concrete topping reduction in deflection is observed in the range of 32.26–33.63%, while for 140 mm concrete thickness the range is 40.96–42.66%. • The increase in depth of concrete slab reduces slip in the range of 23.29–25.32%. • Marginal reduction in slip (1.52–1.96%) as well as deflection (1.72–1.92%) is seen due to increase in profiled deck sheet thickness. • The models with different shape of intermediate stiffener, i.e., rectangular type and V-type in the web were observed to have different behavior than the models without the stiffener. Reduction in deflection and slip is achieved by using profiled sheet having intermediate stiffeners, and profiled sheet with V-type intermediate stiffener gives better reults. Acknowledgements The authors want to thank Mr. Ashish Shete, Prescient Informatics Pvt. Ltd. Colhapur for their kind collaboration.

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References 1. Porter ML, Ekberg Jr CE (1971) Investigation of cold-formed steel-deck-reinforced concrete floor slabs. Scholars’ Mine 2. Johnson RP (2004) Composite structures of steel and concrete 3. Ordija JL (2006) Structural performance of fiber-reinforced and welded wire fabric-reinforced concrete composite slabs 4. Evans HR, Wright HD (1998) Steel-concrete composite structures. In: Narayanan R (ed). Elsevier Applied Science Publishers 5. Li X, Zheng X, Ashraf M, Li H (2017) Experimental study on the longitudinal shear bond behavior of lightweight aggregate concrete—closed profiled steel sheeting composite slabs. Constr Build Mater 156:599–610. https://doi.org/10.1016/j.conbuildmat.2017.08.108 6. Hedaoo N, Raut N, Gupta L (2015) Composite concrete slabs with profiled steel decking: comparison between experimental and simulation study. Am J Civ Eng 3:250–261. https://doi. org/10.11648/j.ajce.20150305.13 7. Johnson RP, Shepherd AJ (2013) Resistance to longitudinal shear of composite slabs with longitudinal reinforcement. J Constr Steel Res 82:190–194. https://doi.org/10.1016/j.jcsr.2012. 12.005 8. Baskar R (2012) Experimental and numerical studies on composite deck slabs. Int J Eng Technol 2:1116–1125 9. Abdullah R (2004) Experimental evaluation and analytical modeling of shear bond in composite slabs 10. Abdullah R (2004) Experimental evaluation and analytical modelling of shear bond in composite slabs. Ph.D. thesis University Virginia, 147. https://doi.org/10.1080/10255840903337848 11. Attarde S (2014) Nonlinear finite element analysis of profiled steel deck composite slab system

A Brief Review of Structural Aspects of IS 16700:2017 Vikalp Gupta , Sanket Rawat , Ravi Kant Mittal and G. Muthukumar

Abstract Rapidly increasing urbanisation and subsequently ascending shortage of land in the urban areas has pushed the design engineers to switch to the utilisation of the vertical spaces in the form of high-rise buildings and reduce the horizontally vast design popular in the previous era. However, this step not only enhances the criticality of the design processes but also increases our dependency on design codes. Talking specifically about India, the dependency of Indian design community was majorly on international codes due to the non-availability of a design code for tall buildings. It also gave rise to a wide gap in the design community about different provisions. However, recently Bureau of Indian Standards has launched First Tall Building Code of India, IS 16700:2017 “Criteria of Structural Safety of Tall Concrete Buildings.” Despite a good effort of bringing the Indian design community at the same base scale, this code still lacks in a clear depiction of certain aspects. It is also felt that commentary of this code may be provided in a similar fashion as of ASCE 07:2016, ACI 318:2014 to facilitate the adoption of the code. As a first step to it, this study is mainly aimed towards understanding some of the critical structural aspects of the code so as to develop a better understanding in practitioners and design engineers about it. Moreover, some critical clauses are also highlighted through a comparison of the same with various existing international standards. Keywords Tall buildings · Damping · Moment resisting frame · Urbanisation

1 Introduction India is considered as the fastest growing developing country in the world with its construction sector at peak level in the present situation. This has not only given rise to urbanisation but also has indirectly augmented the scarcity of land. It has also forced the construction to move in the vertical direction rather than the earlier V. Gupta (B) · S. Rawat · R. K. Mittal · G. Muthukumar Department of Civil Engineering, BITS Pilani, Pilani Campus, Pilani 333031, Rajasthan, India e-mail: [email protected] © Springer Nature Singapore Pte Ltd. 2020 S. Adhikari et al. (eds.), Advances in Structural Engineering and Rehabilitation, Lecture Notes in Civil Engineering 38, https://doi.org/10.1007/978-981-13-7615-3_7

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preferred choice of horizontally wide plan structures. In spite of all of these crucial requirements of multi-storey structures, there existed no code till October 2017 in India to guide the design engineers of the country about the requisite provisions for design of structural components of tall building. Though the international standards are referred in this situation, it cannot be considered effective to use them in Indian scenario due to difference in quality control, and sometimes, the exact conversion of different associated parameters also becomes difficult. Publication of first tall building code of India, IS 16700 [1] in November 2017 is a commendable step taken by Bureau of Indian Standards and is definitely a significant measure towards clearing the aforementioned factors responsible for arising uncertainty in the Indian designs. This code is applicable up to a building height of 250 m which states the typical condition of India in terms of advancement and hence would definitely be able to set up a baseline among the practitioners across the country dealing with the design of tall buildings. Only the clauses related to concrete buildings are covered in the code, and the steel structures and composite structures are not discussed. The code emphasises on choices for adoption of structural systems and methods of structural analysis, height limitation of different structural system, issues to be considered in design of foundations, etc. However, along with a new code comes quite a few clarifications at the user’s level. The reason for this may be attributed to the fact that the clauses are misinterpreted at the user’s level due to lack of clarity. It is felt by the authors that, to increase the awareness about the proper design philosophies among the practitioners, a commentary can be made available for this code in the similar lines as provided for ASCE 7 [2], ACI 318 [5], etc. As a first step to it, this paper is mainly aimed towards understanding some of the critical structural aspects of the code so as to develop a better understanding among the practitioners. A brief interpretation of some of the critical clauses related to structural design has been provided along with the comparison of the same with the existing international standards. It has been observed that some of the clauses may require a detailed explanation and may be modified appropriately in the subsequent versions.

2 Review of Some Important Provisions of IS 16700 2.1 Clause 5.4.1: Lateral Drift When design lateral forces are applied on the building, the maximum inter-storey elastic lateral drift ratio (max /hi ) under working loads (unfactored wind load combinations with return period of 50 years), which is estimated based on realistic section properties mentioned in Clause 7.2 of IS 16700 [1], shall be limited to H/500. Here, max = maximum relative lateral displacement within the storey, hi = inter-storey height of ith floor in the building and H = building height from base to roof level. For a single storey, the drift limit may be relaxed to hi /400. For earthquake load (factored) combinations, the drift shall be limited to hi /250.

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Author’s interpretation: As per ASCE 7 [2], drift limits are in the order of 1/600–1/400 of the building height. The Indian code limit also falls in this range, and it has been observed that the above-mentioned limits are sufficient to curtail damage to cladding and non-structural walls and partitions. For brittle cladding, the smaller drift limits may be suitable. Truby [3] has mentioned that in spite of successful use of inter-storey drift limit in the range of hi /500 to hi /200 in the past, hi /300 can also be a good balance.

2.2 Tables 1 and 2 of IS 16700 [1] Author’s interpretation: It is observed from Tables 1 and 2 of the IS 16700 [1] that moment-resisting frame (MRF) cannot be used in seismic Zone IV and V. The reason for not using moment-resisting frame system for a building of height 50 m is not made clear. It is also to be noted that a lot of tall building with height greater than 50 m have already been constructed in Zone IV and V and avoiding moment-resisting frame for 15-storey building does not seem a cost-effective option. Moreover, as per Truby [3], the MRF is permitted till the height of 75 m. Fintel and Khan [4] also suggested that for rigid frame system, 20-storey building can be constructed which is nearly 60 m, considering the height of each storey as 3 m. Here the explanation of completely eliminating MRF may be certainly required.

Table 1 Different structural systems and their applicability as per limiting height, in metre [1] S. No.

Seismic zone

Structural system Moment frame

Structural wall

Located at core

Structural wall + moment frame

Structural wall + perimeter frame

Structural wall + framed tube

Well distributeda

a.

V

NA

100

120

100

120

150

b.

IV

NA

100

120

100

120

150

c.

III

60

160

200

160

200

220

d.

II

80

180

220

180

220

250

a Well-distributed shear walls are those walls outside of the core that are capable of carrying at least

25% of the lateral loads

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Table 2 Maximum slenderness ratio for different structural systems as per zone [1] S. No.

Seismic zone

Structural system Moment frame

Structural wall

Located at core

Well distributeda

Structural wall + moment frame

Structural wall + perimeter frame

Structural wall + framed tube

a.

V

NA

8

9

8

9

9

b.

IV

NA

8

9

8

9

9

c.

III

4

8

9

8

9

10

d.

II

5

9

10

9

10

10

2.3 Clause 5.6.2: Opening in Floor Systems Clause 5.6.2.1: Openings in floor diaphragm shall not be permitted along any floor diaphragm edge, unless perimeter members are shown to have stability and adequate strength. Clause 5.6.2.2: The maximum area of openings in any floor diaphragm shall not exceed 30% of the plan area of diaphragm. Transfer of lateral forces from diaphragm to lateral load resisting vertical elements shall be ensured using collector elements, if required. Author’s interpretation: As per ACI 318 [5], opening of any size can be permitted in slab system if the design strength can be confirmed to be equal to or greater than the required strength. On a similar note, ASCE 7 [2] has also specified provisions for providing sufficient reinforcement at the edge of the opening to ensure effective transfer of forces, confirming that the opening does not interfere with the strength and stability. Also, it has been mentioned that interrupted reinforcement due to opening shall be added on the sides of the opening. While modelling slabs in commercial analysis software, the floor diaphragm is considered as rigid. However, the openings in diaphragm cause loss in its rigidity and hence reduce stiffness which results in decrease in member load carrying capacity. Opening results in more complicated and unpredictable behaviour of floor diaphragm. Khajehdehi and Panahshahi [6] have also concluded that as the opening size increases, the effect of out-of-plane loading on in-plane capacity reduction in the slabs becomes less significant; and for smaller size of opening, a very less variation is observed in the in-plane behaviour of the slabs in comparison with that of solid slabs. Therefore, while providing interrupted reinforcement at the edges, it is felt that there is need of more clarity in the bar scheduling at the edges of the opening to achieve better transfer of forces and ensure rigidness of diaphragm. This procedure is also adopted internationally, e.g. in NZS 3101 standard [7].

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As it is mentioned in the IS 1893 [8] that due to opening in slab, the behaviour of diaphragm changes to flexible, and thus, the lateral shear force is not shared by the frames and vertical members in accordance with their lateral translational stiffness. It has been found that more the opening close to the edges of the slab, the effect of flexible diaphragm upsurges and thus becomes more problematic. In IS 1893 [8], if opening is more than 50%, then it is said to have in-plane stiffness discontinuity and the slab will be treated as flexible. Here in this code, they are limiting a maximum area of opening to 30% of the plan area of diaphragm and thus underestimating the nature of diaphragm, i.e. flexible or rigid. This lower limit might have been taken to be on safer side as tall buildings are sensitive structure but reason behind taking 30% is not clarified which must be important to study the opening aspects in relation to tall buildings.

2.4 Clause 5.6.3: Natural Frequency of Floor System: The Natural Vertical Vibration Frequency of Any Floor System Shall not Exceed 3 Hz Without Demonstration of Acceptability Using Rational Procedures Author’s interpretation: This clause might lead to misunderstanding as it implies that natural frequency of any floor shall not exceed 3 Hz. As stated by AISC [9] and Murray [10] that conventionally, the design of floors is performed by limiting the natural frequency between 5 and 8 Hz, and it suggests that deflection due to live load should be less than span/360 which was common in construction practice long time back. However, after the development of limit state design, the floor system has become lighter in weight and hence is more flexible resulting in higher natural frequencies. Also, it is mentioned that fundamental frequency of floor system should not be less than 3 Hz and we need to avoid such floor system with such low frequency because the “rogue jumping” may take place. From the studies performed by Allen and Rainer [11], Allen et al. [12], it has been observed that human interaction and the associated activity with the structure impart dynamic forces to a floor at frequencies in the range of 2–6 Hz. If the vibration of the floor system occurs with the fundamental frequency between this range and is periodic in nature e.g. vibration arising from dancing, cheering by a large number of people etc., it may cause resonant amplification. To prevent resonance caused due to rhythmic activities, tuning of floor system is necessary so as to avoid the coincidence of the natural frequency with the frequency of the excitation. Also, the natural frequency of structural elements and assemblies should be greater than 2.0 times the frequency of any steady-state excitation can be followed as a general rule to which they are exposed; otherwise, the vibration isolation is the best available solution to provide. Several investigations have revealed that control of floor stiffness is a very efficient way to reduce the objectionable vibrations arising due to walking and other similar

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human activities [10]. The fundamental frequency of vibration (f o ) of this type of system is given by: π fo = 2L 2

 EI ρ

(1)

Also,  fo =

18 

(2)

Here, EI L ρ 

flexural rigidity of the floor, span length, mass per unit length and maximum deflection caused by dead load plus participating live load (in mm).

The frequency obtained with the above relations can be compared with the minimum natural frequencies for mitigating walking vibrations in various occupancies. This guideline to limit floor vibration seems to be provided only to identify the crucial situations where special considerations may be given.

2.5 Clause 6.2.2.4: The Damping Ratio Considered Shall not Be Greater Than 2% of Critical for Concrete Buildings Author’s interpretation: This clause plays a very important role from the modelling point of view. It is also to be noted here that in the draft version of IS 16700 [1], BIS had provided the damping ratio as 1.5% for composite buildings and 1% for steel buildings, but it was removed afterwards in the final version. The important parameter to keep in mind is that the value of damping as mentioned here in the code as 2% is to be used for site-specific wind tunnel studies and not taken in context of IS 1893 [8] which is given as 5% in case of seismic analysis. Hence, it can be understood that the designer has to consider two types of damping, i.e. 2 and 5% for wind tunnel studies and earthquake analysis respectively.

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2.6 Clause 6.3.1: Vertical Shaking Shall Be Considered Simultaneously with Horizontal Shaking for Tall Buildings in Seismic Zone V Author’s interpretation: This clause can be better explained from IS 1893 [8] which suggests that the vertical shaking must be considered for the following cases—buildings lying in zone IV or V, structure has plan or irregularity, structure is rested on soft soil, structural members or sub-systems with large horizontal overhangs. Therefore, just to be in coherence with the guidelines of IS 1893 [8], zone IV should also be added in the clause.

2.7 Table 3 of IS 16700 [1]: Cracked RC Section Properties from the Table for Structural Elements i.e. Walls for Factored Loads Moment of Inertia Is Given as 0.7Ig (Where Ig = Gross Moment of Inertia) Author’s interpretation: It is observed that Table 3 of the code IS 16700 [1] matches well with the provisions of ACI 318 [5]. However, ACI 318 [5] has mentioned two sections, i.e. cracked and uncracked for all type of structural elements, which seems to be more appropriate and justified. For walls with cracked section, the moment of inertia is taken as 0.35I g , which is taken nearly double in Indian code. The cracked section √ analysis is based on computing modulus of rupture (f cr ) given by f cr = 0.7 f ck (here f ck = 28-day characteristic cube compressive strength of concrete) and if after the analysis stress obtained is greater than f cr , resulting in cracking of the wall, and thus, there is a need to design that element with stiffness modifiers considering it as a cracked wall. Although if the stress obtained in a structural element (walls) is less than f cr (Signifying that the element will behave as an uncracked section), a value of 0.70I g can be applied as stiffness modifier. The purpose of these modifiers is to provide more realistic result for a particular value of element forces and displacement taking into account the cracking effect. Here it can be inferred that while taking 0.35I g , the overall stiffness of a particular structure will drop due to reduction in stiffness modifiers resulting in sufficiently large lateral displacement [13]. At the same time, while assuming the lower stiffness of a particular element (due to cracking) means the less force is attracted by the element which results in higher transfer of forces in the nearby adjacent members with high stiffness which is not cracked. Therefore, considering cracked and uncracked section for crucial structural member like walls seems to be a more realistic reflection in the calculation of its stiffness.

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Table 3 Cracked reinforced section properties [1] S. No.

Structural element

Unfactored loads

Factored loads

Area

Moment of inertia

Area

Moment of inertia

1.0Ag

0.35I g

1.0Ag

0.25I g

a.

Slabs

b.

Beams

1.0Ag

0.70I g

1.0Ag

0.35I g

c.

Columns

1.0Ag

0.9I g

1.0Ag

0.70I g

d.

Walls

1.0Ag

0.9I g

1.0Ag

0.70I g

2.8 Clause 7.3.11: Stiffness of Slab Frames (That Is, Slab-Column Frames) Shall Be Ignored in Lateral Load Resistance, in All Seismic Regions Author’s interpretation: It is not clearly mentioned whether out-of-plane stiffness or in-plane stiffness can be neglected. In general, only the out-of-plane stiffness of flat slab which contributes to the lateral stiffness of the building can be neglected and not the in-plane stiffness which should be considered at lower and upper bound for sensitivity analysis.

3 Conclusions The study of codal provisions of IS 16700:2017 and other international standards has led to an observation that several structural-related aspects need further explanation to provide clarity among practitioners and design engineers. For instance, completely neglecting the moment-resisting frames in Zone IV and V in tall buildings, limiting the maximum area of openings to 30% and overlooking the effect of Vertical shaking in Zone IV may desire serious concern that needs to be clarified. The clause about limiting the natural frequency of floor system below 3 Hz should also be relooked. Overall, this study provides a brief explanation of a few important clauses of IS 16700:2017 which will be helpful in imparting the design engineers a deeper insight about the same, and it can be perceived as a recommendable initiative in the field of tall buildings, hence can be considered as a good start towards the development of a complete commentary for this code.

4 Notation EI = Flexural rigidity of the floor f cr = Modulus of rupture (in MPa) f ck = 28-day characteristic cube compressive strength of concrete (in MPa)

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f o = Fundamental frequency of vibration hi = Inter-storey height of ith floor in the building H = Building height from the base to its roof level, (a) Excluding the height of the basement storeys when the basement walls are connected with the ground floor slab or basement walls are fitted between the building columns, but (b) Including the height of basement storeys if basement walls are not connected with the ground floor slab and basement walls are not fitted between the building columns. L = Span length ρ = Mass per unit length  = Maximum deflection caused by dead load plus participating live load (in mm) max = Maximum relative lateral displacement within the storey I g = Gross Moment of Inertia.

References 1. IS 16700 (2017) Criteria for structural safety of tall concrete buildings. Bureau of Indian Standards, New Delhi, India 2. ASCE/SEI 7 (2016) Minimum design loads and associated criteria for buildings and other structures. American Society of Civil Engineers, Reston, Virginia 3. Truby A (2014) Structural design of concrete buildings up to 300 m tall. International Federation for Structural Concrete (Fib), Lausanne, Switzerland 4. Fintel M, Khan FR (1969) Effect of column creep and shrinkage in tall structures—prediction of inelastic column shortening. ACI J 66(2):957–967 5. ACI 318 (2014) Building code requirements for structural concrete and commentary. American Concrete Institute, Farmington Hills, MI 6. Khajehdehi R, Panahshahi N (2016) Effect of openings on in-plane structural behaviour of reinforced concrete floor slabs. Elsevier J Build Eng 7:1–11 7. NZS 3101 Part 1 (2006) Concrete structures standard. Wellington, New Zealand 8. IS 1893 Part-1 (2016) Criteria for earthquake resistant design of structures. Bureau of Indian Standards, New Delhi, India 9. Murray TM, Allen DE, Ungar EE (2003) Floor vibrations due to human activity. American Institute of Steel Construction, USA 10. Allen DE, Murray TM (1993) Design criterion for vibrations due to walking NRCC-34140. Eng J (American Institute of Steel Construction) 30(4):117–129 11. Allen DE, Rainer JH (1976) Vibration criteria for long-span floors. Can J Civ Eng 3(2):165–173 12. Allen DE, Rainer JH, Pernica G (1985) Vibration criteria for assembly occupancies. Can J Civ Eng 12(3):617–623 13. Rokhgar N (2014) A comprehensive study on parameters affecting stiffness of shear wall-frame buildings under lateral loads. M.Sc. thesis, The State University of New Jersey, New Jersey, USA

Are FRPs the Way Forward for the Blast Retrofitting of Reinforced Concrete Structures? Aashish Kumar Jha, Abhiroop Goswami and Satadru Das Adhikary

Abstract The surge in the occurrence of intentional and accidental blast events around the world has highlighted the susceptibility of the infrastructure to this type of extreme loading. For new construction, blast-resistant design philosophy or guidelines can be incorporated during the initial stages of conception. However, for the existing structures, retrofitting schemes need to be devised to augment the blast resistance of the structures. The retrofitting schemes particularly employing the use of fiber-reinforced polymers (FRP) as compared to the others are very popular due to their on-field ease of application. This study explores the effectiveness and feasibility of the application of FRPs in this domain. The study further seeks to comprehensively address the realms of the current knowledge state in this field, and moreover to direct further attention of the global research community to address the shortcomings in this field. Keywords Blast loading · Blast retrofit · Fiber-reinforced polymer · CFRP · GFRP

1 Introduction The occurrence of the events such as the bombing of The World Trade Center in 1993, Oklahoma City bombing in 1995, Khobar Tower bombings in 1996, bombing of the US Embassies in Tanzania and Kenya in 1998, bombing of the Australian Embassy in Jakarta in 2004 has clearly brought about the need for the structural retrofitting of the vulnerable structures for these extreme loads. The fatalities arising A. K. Jha (B) · A. Goswami · S. Das Adhikary Indian Institute of Technology (ISM) Dhanbad, Dhanbad, Jharkhand, India e-mail: [email protected] A. Goswami e-mail: [email protected] S. Das Adhikary e-mail: [email protected]; [email protected] © Springer Nature Singapore Pte Ltd. 2020 S. Adhikari et al. (eds.), Advances in Structural Engineering and Rehabilitation, Lecture Notes in Civil Engineering 38, https://doi.org/10.1007/978-981-13-7615-3_8

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Fig. 1 The Alfred P. Murrah Federal Building, Oklahoma City after the explosion [3]

due to an explosion may not just be attributed to the direct effect of the explosion but also to the collapse of the structure and the generation of debris due to the blast. In fact the criticality of a structure surviving a blast has been documented in the ASCE Report of the 1995 Oklahoma city blast, wherein it has been noted that the collapsed section of the Alfred P. Murrah building accounted for 153 casualties of the total 175 people present there (in that part of the building) while the un-collapsed section saw 10 casualties of the total 186 present in that section of the building [1]. This stark difference demonstrates the fact that had the building not suffered a partial collapse, the casualties could have been significantly reduced, and this further strengthens the need for the adequate retrofitting of the structures that are vulnerable to these loads. The damaged Alfred P. Murrah building after the explosion has been shown in Fig. 1. An explosion is characterized by the rapid and sudden release of an enormous amount of energy which results in the formation of a highly pressurized gas mass (pressures typically of the order of 300 kbar/30 GPa) having temperatures in the order of 3000–4000 °C. These gases then radially expand outward which consequently results in the formation of a compressed air-front in front of these gases containing most of the energy released by the explosion [2]. The pressure exerted by these gases is called overpressure, and after a certain time, this overpressure decays and falls below the ambient pressure resulting in a negative pressure region to neutralize which air from the nearby region flows in. A typical pressure versus time plot has been shown in Fig. 2. The pressure varies a function of time and at any instance of time, ‘t,’ may be defined by the modified Friedlander’s equation as,   t −b t e tpos (1) P(t) = Po + Pso+ 1 − tpos

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Fig. 2 A pressure versus time plot for a blast wave

where Po Ambient pressure; Pso+ Peak positive overpressure and b Decay parameter. The impulse generated by this blast wave for the positive and negative phases is given by, t2

Ipos = ∫ P(t)dt

(2)

t1

t3

Ineg = ∫ P(t)dt

(3)

t2

while the total generated impulse is given by, t3

Itotal = ∫ P(t)dt

(4)

t1

The currently employed rationale to improve the blast resistance of a structure includes to either increase the strength of the material or to increase the section parameters or to increase the ductility of the member. Employing high strength materials may be suitably employed during the inception stages of the structure; however, for an existing structure this might not be possible. Thus, for such cases, the only remaining viable options are to increase the mass or the ductility of the

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existing structure. Another constraint which must also be accounted for in such cases is to limit the weight of the retrofitting material such that when added to the structure, it does not exceed the design capacity of the foundations. It is with regard to the above along with the high strength-to-weight ratios and the ease of applicability that marks the popularity of the FRPs as a blast retrofitting material. FRPs that find extensive applications in the field of civil engineering, on the basis of the reinforcing fiber, may further be categorized as carbon fiber-reinforced polymer (CFRP), glass fiber-reinforced polymer (GFRP), and aramid fiber-reinforced polymer (AFRP).

2 Objectives and Research Significance of the Current Study The current study presents an overview of the feasibility of using FRPs as a blast retrofitting material. The study explores a significant extent of the work undertaken in this field in the form of experimental testing, analytical modeling, and finite element analysis (FEA) and organizes them under the relevant sections dealing with the retrofitting of various structural members such as reinforced concrete (RC) slabs, columns, beams, and walls. The study was aimed at establishing the current knowledge base and features the scope and the pressing need for further research in this field. Moreover, the study also investigates the failure modes exhibited by the structural members subjected to blast loading in an attempt to provide a better understanding relating to the design of the blast retrofitting solutions.

3 Fiber Reinforced Polymers FRPs are composites essentially consisting of a polymer matrix reinforced with embedded high strength fibers. The typical section of an FRP laminate has been shown in Fig. 3. An FRP system comprises primarily of high strength fibers of small diameters embedded in a polymeric resin matrix. The fiber gives strength and stiffness to the composite, while the resin matrix provides for the stress transfer between fibers and acts as a bonding agent between the concrete or masonry substrate and the composite laminate. The fiber in the composite laminate can be oriented in a single direction (unidirectional) or along multiple directions (multidirectional), providing significantly improved in-plane tensile resistance in only one or more directions, respectively. For civil engineering applications, the most widely used types of matrix are the epoxy resin, vinyl resin, polyesters, and phenolic resins, while the most widely employed fibers are the carbon fibers, the glass fibers, and the aramid fibers. Carbon fiber composites are characterized by higher strength and stiffness but offer significantly lower strain capacities as compared to the glass and aramid FRPs.

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Fig. 3 A schematic diagram of a typical unidirectional FRP laminate [4]

AFRPs on the other hand offer strength and stiffness values ranging between those of the CFRPs and GFRPs but are also governed high toughness, impact resistance, and thermal and electrical insulation. The FRP laminating can be applied to the concrete or the masonry walls as either a wet layup or a pre-cured system. For the wet layup system, a mat is applied to the wall which contains only the fibers and the resin is placed around the fibers, and thus, bonding between the fibers and the structural member is achieved. The resin is thus cured in situ against the structural member similar to a cast in situ concrete member. The pre-cured system is similar to the wet layup system except that the curing is completed at the manufacturing site.

4 FRP Retrofitting of RC Beams There is very limited research available on the FRP strengthening of beams subjected to blast loading as compared to the other structural members. A preliminary investigation governing the performance of FRP retrofitted beams was conducted by Ross et al. [5]. The experimental regime consisted of evaluating the response of six simply supported RC beams of 2.74 m × 0.2 m × 0.2 m reinforced with two 16-mm-diameter rebar to a blast load generated due to 110.6 kg ammonium-nitrate fuel oil (ANFO). The tests were conducted with the ANFO suspended directly over the mid span of the beam. Unfortunately, they could not collect all the necessary data from the tests due to the pressure transducers sustaining severe damage during the tests. It was, however, observed that the un-retrofitted control beam failed due to the explosion while the FRP strengthened beams survived the explosions indicating that the FRP retrofitting increases the blast resistance of the members. To the best of our knowledge, no other study with regard to the blast retrofitting of RC beams with FRPs has been carried out.

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5 FRP Retrofitting of RC Columns Columns are one of the most important members of a framed structure since the columns transfer the vertical loads from the structure to the foundation, and thus, the stability and the survival of a structure are primarily governed by the performance and the sustenance of the columns under these loads. The rationale behind the adapted retrofitting design scheme should be such that the columns offer sufficient residual resistance to aid with the rescue and relief operations. The blast performance of FRP retrofitted columns has been exhaustively investigated by Crawford et al. [6], Morrill et al. [7], Rodriguez-Nikl et al. [8], and Rodriguez-Nikl et al. [9]. Crawford et al. [6] conducted a full-scale experimental testing on a four-storey building with 350 mm square columns. The testing included evaluating the performance of two identical columns, a control, and a CFRP retrofitted column under similar blast loading. It was observed that the un-retrofitted control column failed in shear at the top and bottom fractions of the column while the central section remained relatively unscathed. The residual displacement at the center of the column was noted to be 250 mm. The CFRP retrofitted column reinforced with six horizontal shear strips and three vertical flexural strips on the other hand was characterized by a relatively elastic response with no significant permanent deflection. It was thus concluded that the application of the CFRP strips enhanced the blast performance of the column. Figure 4 elucidates the performance of the control and the CFRP strengthened columns. Morrill et al. [7] utilized the above test and other extensive concept and laboratory tests to investigate the reliability of a Windows-based program developed by Karagozian and Case, CBARD (column blast analysis and retrofit design). The developed program employed an advanced single degree of freedom (SDOF) model to compute the response and design the retrofitting (CFRP and steel) for the columns and walls. The study concluded that accomplished users could use the developed program to gain insights into the behavior of the columns or walls subjected to blast loading and effectively design the retrofitting for these members. Further investigations encompassing the enhancements in the blast resistance of CFRP retrofitted columns were conducted by Rodriguez-Nikl et al. [8]. The experimental regime consisted of evaluating the performance of 10 RC columns under blast-like loads generated by a blast simulator. The columns were detailed to replicate the performance of a non-seismic column. It was observed that the non-strengthened columns were marked by very high shear loads at the ends while being characterized by failure at low load levels brought about by the brittle shear mechanism. The CFRP retrofitted columns on the contrary were seen to be marked by the formation of ductile flexural hinges which added to the strength and the ductility of the columns. Similar observations have also been documented in the study conducted by Rodriguez-Nikl et al. [9] on the same subject. The conducted studies on the blast performance of columns highlight that the nonretrofitted RC columns subjected to blast loads are likely to be governed by shear failure along the sections adjacent to the supports [6–9] while the retrofitted columns

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Fig. 4 Performance of the control and the CFRP retrofitted column [6]

on the other hand have been marked by a more elastic response being characterized by a ductile-flexural failure. Thus, the design rationale should be marked by enhancing the shear resistance of the columns at the sections adjacent to the support although further research on this is also recommended to study the failure mechanisms for blast loads being generated to near-field and contact type explosions since the response for such cases may be dominated by significant local response. It was also noted that the retrofitting solution employed for the above studies is limited only to CFRP strengthening, and thus, further research with GFRP and AFRP is also recommended.

6 FRP Retrofitting of RC Slabs Silva and Liu [10] experimentally investigated the blast performance of CFRP and steel fiber-reinforced polymer (SFRP) strengthened slabs. The study highlighted that the slabs retrofitted on both the faces with the FRP laminates exhibited a much better performance as compared to the non-retrofitted control specimen. Furthermore, it was also noted that the strengthening of the slabs on the tension side only, did not significantly improve the blast resistance of the slabs. This observation was brought about by the negative moments that were developed during such extreme loading events. To add to it, it was also documented that the SFRP retrofitted slabs also exhibited satisfactory performance equivalent to that exhibited by the CFRP

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Fig. 5 Blast resistance of the control, CFRP and SFRP retrofitted slabs [10]

strengthened slabs. The performance of the strengthened and the non-strengthened slabs has been presented in Fig. 5. Ghani Razaqpur et al. [11] evaluated the blast resistance and the residual strength of GFRP retrofitted slabs. The experimental regime consisted of subjecting the slabs to blast loading which was then followed by determining the residual strength of the slabs under quasi-static loads. The study concluded that the GFRP retrofitted slab was marked by a significantly better blast performance as compared to the control slab while also exhibiting almost 75% higher residual strength as compared to the control. The study was, however, met with inconclusive results when the charge weight was increased for the same standoff distance. Kim et al. [12] designed an experimental study to investigate the blast performance of CFRP, basalt fiber-reinforced polymer (BFRP), polyurea (PU), and CFRP-PU retrofitted RC slabs. The study documented that the retrofitted slabs were governed by flexural failure while the control slabs were seen to be governed by the shear failure mechanism. It was also observed that the effectiveness of the retrofitting system in reducing the maximum deflections was 21.4, 19.8, 15.7, and 37.4%, respectively, for CFRP, BFRP, PU, and CPU. It was thus concluded that the FRPs can be suitably applied to structures susceptible to blast loads. It was also observed that the slabs retrofitted with BFRP were characterized by higher residual deflections as compared to the average for the control slabs.

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Tanapornraweekit et al. [13] reported the behavior of CFRP- and GFRPstrengthened slabs subjected to two detached blasts. The study encompassed an experimental as well as a numerical approach. The retrofitting scheme employed included slabs strengthened on both sides with a single layer of GFRP and slabs rehabilitated on both the faces with one laminate of GFRP and one laminate of CFRP. From the conducted experimental investigation, it was observed that as the intensity of the blast increases (for a constant standoff distance), the response governing the control slabs changes from a global flexural response to failure due to a combination of flexure and concrete spalling. The slabs retrofitted with a single GFRP laminate after the second blast were seen to exhibit flexural cracks that had penetrated throughout the entire depth of the slab along with some diagonal shear cracks along the sides of the slabs which were not there after the first blast event. The GFRP-CFRP rehabilitated slab was also seen to exhibit a similar response sustaining negligible damage for the first blast event while being characterized by flexural and diagonal shear cracks after the second blast. The numerical analysis for the study was conducted using LS-DYNA, and the performance of two concrete material models, the K&C model (MAT 72R3) and the Winfrith concrete model (MAT 84), was evaluated. The study recommended the use of the K&C model for all general applications while the Winfrith concrete model was recommended for cases with involving high reinforcement percentage. Orton et al. [14] investigated the response of the CFRP rehabilitated slabs subjected to close-in blasts. The experimental testing was marked by the use of an anchorage system to achieve effective performance since the failure of the CFRP laminates for such close-in blasts would then have been governed by fiber rupture rather than laminate debonding. The CFRP strengthening was only limited to the tension face. It was observed that as the severity of the blast loading increased, the failure pattern for the non-strengthened slabs changed from spalling and shear failure along the edges to breaching. The strengthened slab on the other hand was marked by a shift from shear failure along the edges to breaching failure although exhibiting a smaller breach as compared to the non-retrofitted slab panel. Other such investigations marked by almost similar outcomes have also been conducted by Wu et al. [15], Ha et al. [16], Yun and Park [17], and Guo et al. [18]. The conducted studies on the blast retrofitting of RC slabs bring about the fact that for a constant standoff, as the blast intensity increases (marked by an increase in the charge weight), the response of the non-retrofitted slabs to the blast loading shifts from a global flexural behavior to a shear failure mechanism along with concrete spalling [12, 13]. On increasing the severity further, being characterized by closein blasts, the response is dominated by a local breaching failure [14]. The FRP strengthened slabs on the contrary have been marked by a significant global flexural response which has added toward the enhancement of the blast resistance of the slabs; however, for the close-in blasts, these schemes involving a tension face retrofitting only have been insufficient for the purpose. Another recommendation which is being made is to apply the retrofitting scheme on both the faces of the slab panels since they may be governed by the development of negative moments.

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7 FRP Retrofitting of RC Walls The effectiveness of the anchors in restricting the premature debonding of the CFRP laminates from the wall was reported by Mutalib and Hao [19]. The numerical simulations encompassing the study were carried out in LS-DYNA. The study concluded that CFRP retrofitting can be effectively employed to improve upon the blast resistance of the RC walls. Further, the use of anchors was also found to be suitable in restricting the premature debonding; however, since the anchors were also marked by high stress concentrations around them, their configuration was also noted to require careful planning. Pezzola et al. [20] studied the behavior of CFRP-strengthened RC walls under blast-like loading generated by a blast simulator. The experimental testing concluded that the specimens were governed by spall failure along with the separation of the CFRP laminates. The study employed an anchorage system to improve upon the bonding between the member and the laminate. It was also documented that the separation of the laminate was not same as debonding failure. Further, the laminates were also characterized by a ‘tearing-off’ action due to excessive stress concentrations around the anchors. Further, SDOF analyses were also conducted to gain a better understanding of the response of the RC walls subjected to blast loads. The SDOF model was adjusted to allow the CFRP debonding strain to be the governing parameter. The SDOF analysis revealed that the response of the system was brittle in nature since the steel reinforcement had not yielded. Further, numerical simulations in LS-DYNA were also conducted. The obtained results were observed to be in good agreement with the experimental results. From the conducted review of the literature on the FRP strengthening of RC walls, it can be inferred that the response of the RC walls strengthened with GFRP and AFRP laminates has not been investigated, and thus, further research on that is also recommended. It can also be further inferred that although anchorage systems are effective in improving the bonding characteristics between the laminate and the member, however, their configuration needs careful planning since the anchors will be characterized by excessive stress concentrations around them. Further, the walls were also seen to exhibit spalling failure as one of the failure modes, and thus, the retrofit system should be rationalized accordingly.

8 Summary From the survey of the available literature in the public domain, the following conclusions were drawn: 1. FRP laminates are effective in enhancing the blast resistance of the members; however, for the close-in blasts, the use of FRP laminates only might not prove to be sufficient for the purpose, and thus, the feasibility of a hybrid retrofitting

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scheme involving FRP and aluminum foam or PU or steel jackets should be further explored. 2. The use of AFRP as a suitable blast retrofitting material is yet to be explored. 3. SFRP has shown encouraging results as a blast retrofitting material, and thus, its applicability may further be explored. 4. The use anchors can be effectively employed to prevent premature debonding; however, their application should be governed by exercising sufficient caution as improper arrangements can lead to laminate rupture. This further opens up the scope for methods to improve the bonding between the member and the laminates.

References 1. ASCE (1996) The Oklahoma City Bombing: improving building performance through multihazard mitigation, FEMA 277, Federal Emergency Management Agency, Renton, VA, American Society of Civil Engineers 2. Ngo T, Mendis P, Gupta A, Ramsay J (2007) Blast loading and blast effect on structures—an overview. EJSE Special Issue: Loading on Structures, pp 76–91 3. Starossek U, Wolff M (2005) Design of collapse-resistant structures. In: JCSS and IABSE workshop on robustness of structures 4. Obaidat Y, Heyden S, Dahlblom O, Abu-Farsakh G, Abdel-Jawad Y (2011) Retrofitting of reinforced concrete beams using composite laminates. Constr Build Mater 25:591–597 5. Ross CA, Purcell MR, Jerome EL (1997) Blast response of concrete beams and slabs externally reinforced with fibre reinforced plastics (FRP). In: Proceedings of the structure congress XV—building to last, Portland, USA, pp 673–677 6. Crawford JE, Malvar LJ, Morrill KB, Ferritto JM (2001) Composite retrofits to increase the blast resistance of reinforced concrete buildings. In: Tenth international symposium interaction of effect of munitions with structures, pp 1–25 7. Morrill KB, Malvar LJ, Crawford JE, Ferritto JM (2004) Blast resistant design and retrofit of reinforced concrete columns and walls. In: Proceedings of the ASCE structures conference, Nashville, Tennessee, USA, pp 1–8 8. Rodriguez-Nikl T et al (2009) Carbon fiber composite jackets to protect reinforced concrete columns against blast damage. Struct Congr 2009:1–9 9. Rodriguez-Nikl T, Lee C-S, Hegemier GA, Seible F (2012) Experimental performance of concrete columns with composite jackets under blast loading. J Struct Eng 138(1):81–89 10. Silva PF, Lu B (2007) Improving the blast resistance capacity of RC slabs with innovative composite materials. Compos Part B Eng 38:523–534 11. Ghani Razaqpur A, Tolba A, Contestabile E (2007) Blast loading response of reinforced concrete panels reinforced with externally bonded GFRP laminates. Compos Part B Eng 38:535–546 12. Kim JHJ, Yi NH, Kim SB, Choi JK, Park JC (2009) Experiment study on blast loading response of FRP-retrofitted RC slab structures. In: Proceedings of the second official international conference of international institute for FRP in construction for Asia-Pacific Region, Seoul, Korea, pp 533–538 13. Tanapornraweekit G, Haritos N, Mendis P, Ngo T (2010) Finite element simulation of FRP strengthened reinforced concrete slabs under two independent air blasts. Int J Prot Struct 1:469–488 14. Orton SL, Chiarito VP, Minor JK, Coleman TG (2013) Experimental testing of CFRPstrengthened reinforced concrete slab elements loaded by close-in blast. J Struct Eng 140:4013060

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15. Wu C, Oehlers DJ, Rebentrost M, Leach J, Whittaker AS (2009) Blast testing of ultra-high performance fibre and FRP-retrofitted concrete slabs. Eng Struct 31:2060–2069 16. Ha JH, Yi NH, Choi JK, Kim JHJ (2011) Experimental study on hybrid CFRP-PU strengthening effect on RC panels under blast loading. Compos Struct 93:2070–2082 17. Yun S-H, Park T (2013) Multi-physics blast analysis for steel-plated and GFRP-plated concrete panels. Adv Struct Eng 16(3):529–547 18. Guo Z et al (2017) Behavior of GFRP retrofitted reinforced concrete slabs subjected to conventional explosive blast. Mater Struct Constr 50:1–15 19. Mutalib AA, Hao H (2011) Numerical analysis of FRP-composite-strengthened RC panels with anchorages against blast loads. J Perform Constr Facil 25:360–372 20. Pezzola GL, Stewart LK, Hegemier G (2016) Analysis methods for CFRP blast retrofitted reinforced concrete wall systems. Int J Comput Methods Exp Meas 4:247–257

Analytical Study of Triple Friction Pendulum Under a Different Hazard Level of Earthquakes Ankit Sodha, Sandeep Vasanwala, Devesh Soni, Shailendra Kumar and Kanan Thakkar

Abstract The triple friction pendulum (TFP) system is a new generation sliding isolation having four spherical sliding surfaces with three effective pendula. Due to multiple sliding surfaces, TFP system shows highly adaptive behaviour under different hazard level of earthquakes, despite being a passive system. In this research work, a mathematical model and seismic response pertaining to TFP system under maximum considered earthquakes have been described. Series model composed of existing nonlinear element is described along with its hysteretic force–displacement behaviour. Effective period and effective damping in combination with desirable displacement capacity of TFP bearing designs are considered. Due to the presence of multiple sliding surfaces, sliding displacement is distributed over the multiple surfaces and seismic energy is dissipated. It is also found that, at low input, TFP bearing stiffens. It gets soften with the increase in input. And, it gets stiffen against higher levels of input. Thus, it shows highly adaptive behaviour under different hazard levels of earthquake. Keywords Seismic isolation · Triple friction pendulum system · Friction pendulum system · Multi-hazard-level earthquake

1 Introduction As per base isolation is concerned, in the last decade friction pendulum type of base isolation is main focused for the research. Because of its effectiveness for a wide range of earthquake frequency, isolators based on sliding friction are resilient-friction A. Sodha (B) · S. Vasanwala · S. Kumar · K. Thakkar Applied Mechanics Department, Sardar Vallabhbhai National Institute of Technology, Ichchhanath Circle, Surat 395007, Gujarat, India e-mail: [email protected] D. Soni Department of Civil Engineering, Sardar Vallabhbhai Patel Institute of Technology, Vasad, Anand District 388306, Gujarat, India © Springer Nature Singapore Pte Ltd. 2020 S. Adhikari et al. (eds.), Advances in Structural Engineering and Rehabilitation, Lecture Notes in Civil Engineering 38, https://doi.org/10.1007/978-981-13-7615-3_9

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base isolator system [1] and friction pendulum system [2]. To enhance an adaptive behaviour of isolator, a concept of multiple friction pendulum isolators with more capacity of displacement was establish [3]. Multiple friction pendulum isolators are further divided into double concave friction pendulum (DCFP) isolator with twoconcave sliding surfaces [4] and having four sliding surface namely triple friction pendulum (TFP) isolator [5–7].

2 Mathematical Modelling of TFP Bearing The TFP bearing is made up of four stainless steel concave surfaces with Teflon coating nested by a slider as shown in Fig. 1a. The d i , µi, and Ri are the displacement capacity, coefficient of friction, and radius of curvature of the ith spherical surface, respectively. By increasing magnitude of displacement, multiple changes in stiffness and strength are observed due to TFP bearing. Multiple sliding surfaces of the TFP results in more complex force–deformation behaviour compared to currently used isolation systems. The TFP can be modelled as a series of three single concave FP elements as shown in Fig. 1b [5]. Each single FP element has a parallel arrangement of (i) a linear elastic spring element with stiffness (1/Reff ), representing the restoring force developed by the spherical sliding surface; (ii) friction element (µi ), representing the surface friction; and (iii) a gap element (d i ), representing the finite displacement capacity of each sliding surface. The effective radius of curvature and coefficient of friction of the three FP elements of series models are expressed as, R eff1 = Reff2 + Reff3

(1)

R eff2 = Reff1 − Reff2

(2)

R eff3 = Reff4 − Reff3

(3)

µ¯ 1 = µ2 = µ3

(4)

µ¯ 2 = µ1

(5)

µ¯ 3 = µ4

(6)

Here, Reff,i = Ri − hi ; here, the radial distance between pivot point of articulated slider and ith sliding surface is represented by hi .

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(a)

(b)

F

1 R eff 1

1 R eff 2

d1

1 R eff 3 d3

d2

F W

W FPS

FP

FP

Fig. 1 a Schematic diagram and b series model of TFP Table 1 Properties of the TFP design configurations

Properties of the TFP design configurations Reff1 TFP1 3

Reff2

Reff3

Reff4

µ1

µ2

µ3

µ4

0.3

0.3

2.3

0.05

0.01

0.01

0.03

Equivalent properties for series model of TFP TFP1

R eff1

R eff2

R eff3

µ¯ 1

µ¯ 2

µ¯ 3

0.6

2.7

2

0.01

0.05

0.03

2.1 Properties of the Isolation System The TFP configurations designed using above procedure and equations are presented in Table 1. The equivalent properties for the series model are calculated using Eqs. (1)–(6).

108 Table 2 Different levels of excitation at different stages of sliding have been illustrated (refer Fig. 1) [6, 7]

A. Sodha et al.

Stages

Actions

I

Motion starts on surfaces 2 and 3

II

Motion stops on 2 and starts on surfaces 3 and 1

III

Motion stops on surfaces 2 and 3. It occurs on surfaces 1 and 4

IV

Motion reaches to the end on 1 and stops. Sliding on surfaces 2 and 4

V

Motion reaches to the end on 1 and 4 and stops. Motion occurs on surfaces 2 and 3

2.2 Different Stages of Sliding for TFP See Table 2.

3 Earthquake Ground Motions The suites of time histories developed as part of SAC steel project represents different seismic hazard levels ranging from seismic zone 2 to zone 4 (soil-type SD) have been adopted for the present study. Three hazard levels with various probability of occurrence, SLE (50% in 50 years), DBE (10% in 50 years), and MCE (2% in 50 years), are considered. A set of three time histories, one from each of the three bins: SLE, DBE, and MCE, is presented in Table 3 [8].

4 Behaviour of TFP Under Multi-Hazard-Level Earthquakes The time variation of displacement of the three FP elements (x 1 , x 2 , x 3 ) and total isolator displacement (ub ) of TFP1 under LA21 (MCE) are shown in Fig. 2. It is seen that in SLE event, FP4 and FP5 elements remain more in sticking compared to MCE due to its high-friction and low-level shaking while other elements keep on sliding due to relatively lower friction. The hysteretic behaviour of all three FP elements and the TFP system under LA 21 (MCE) is shown in Fig. 3. It shows that the sliding displacement on each surface increases with the increase in earthquake hazard level. For MCE event, the isolator deforms into sliding regime VIII and IX, and the sliding surfaces come in contact with the restrainers as exhibited by sudden increase in slope of hysteretic loop in Fig. 3 [9, 10]. The isolation system designed for MCE is highly damped and very stiff that does not move during more probable, lower-level earthquake. This results in much less

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Table 3 Multiple hazard-level ground motions [8] SLE

DBE

MCE

Record

Scale

Record

Scale

Record

Scale

Label

Factor

Label

Factor

Label

Factor

LA41

0.590

LA01

0.461

LA21

1.283

LA42

0.333

LA02

0.676

LA22

0.921

LA43

0.143

LA03

0.393

LA23

0.418

LA44

0.112

LA04

0.488

LA24

0.473

LA45

0.144

LA05

0.302

LA25

0.868

LA46

0.159

LA06

0.234

LA26

0.944

LA47

0.337

LA07

0.421

LA27

0.927

LA48

0.308

LA08

0.426

LA28

1.330

LA49

0.318

LA09

0.520

LA29

0.809

LA50

0.546

LA10

0.360

LA30

0.992

LA51

0.781

LA11

0.665

LA31

1.297

LA52

0.632

LA12

0.970

LA32

1.297

LA53

0.694

LA13

0.678

LA33

0.782

LA54

0.791

LA14

0.657

LA34

0.681

LA55

0.518

LA15

0.533

LA35

0.992

LA56

0.379

LA16

0.580

LA36

0.101

LA57

0.253

LA17

0.569

LA37

0.712

LA58

0.231

LA18

0.817

LA38

0.776

LA59

0.769

LA19

1.019

LA39

0.500

LA60

0.478

LA20

0.987

LA40

0.657

Fig. 2 Time variation of displacement of the three FP elements (x 1 , x 2 , x 3 ) and total isolator displacement (ub ) of TFP1 under LA 21 earthquake

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Fig. 3 Hysteretic behaviour of all the elements of TFP1 under LA 21 (MCE)

isolation than promised causing damage of non-structural elements, equipment and disturbance to occupants. To achieve desired performance for MCE while maintaining good performance for SLE, the triple friction pendulum bearing should stiffens at SLE. It gets soften with the increase in input DBE, and it gets stiffen again at higher levels of input MCE. An isolation system adopting changes in isolator properties as demanded by input motion is called adaptive isolation system.

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5 Conclusion In this study, nonlinear behaviour of TFP isolator under time history analysis with multi-hazard-level earthquakes; 1. Sliding displacement is distributed, and seismic energy is dissipated owing to multiple sliding surfaces. 2. It is also found that, at low input, TFP bearing stiffens. It gets soften with the increase in input. And, it gets stiffen against higher levels of input. 3. Further as we increase isolator displacement, overall displacement of structure at the base level increases and base shear decreases. 4. Thus, it shows highly adaptive behaviour under different hazard levels of earthquake.

References 1. Mostaghel N, Khodaverdian M (1987) Dynamics of resilient-friction base isolator (R-FBI). Earthq Eng Struct Dynam 15(3):379–390 2. Zayas VA, Low SS, Mahin SA (1990) A simple pendulum technique for achieving seismic isolation. Earthq Spectra 6(2):317–333 3. Tsai CS, Lin YC, Su HC (2010) Characterization and modeling of multiple friction pendulum isolation system with numerous sliding interfaces. Earthq Eng Struct Dynam 39(13):1463–1491 4. Fenz DM, Constantinou MC (2006) Behaviour of the double concave friction pendulum bearing. Earthq Eng Struct Dynam 35(11):1403–1424 5. Fenz DM, Constantinou MC (2008) Modeling triple friction pendulum bearings for responsehistory analysis. Earthq Spectra 24(4):1011–1028 6. Becker TC, Mahin SA (2013) Approximating peak responses in seismically isolated buildings using generalized modal analysis. Earthq Eng Struct Dynam 42(12):1807–1825 7. Dhankot MA, Soni DP (2017) Behaviour of triple friction pendulum isolator under forward directivity and fling step effect. KSCE J Civ Eng 21(3):872–881 8. Somerville P, Anderson D, Sun J, Punyamurthula S, Smith N (1998) Generation of ground motion time histories for performance-based seismic engineering. In: Proceedings 6th national earthquake engineering conference, Seattle, Washington 9. Soni DP, Mistry BB, Jangid RS, Panchal VR (2011) Seismic response of the double variable frequency pendulum isolator. Struct Control Health Monit 18(4):450–470 10. Lee D, Constantinou MC (2016) Quintuple friction pendulum isolator: behavior, modeling, and validation. Earthq Spectra 32(3):1607–1626

Finite Element Simulation of Impact on RCC Water Tank Partheepan Ganesan , M. V. A. N. Jagadeesh Babu, M. Nizamuddin and T. Sai Ram Kiran

Abstract Finite element simulation of the impact analysis of circular and rectangular water tanks subjected to projectile impact has been carried out using ANSYS Explicit Dynamics 15.0. Analyses were performed by considering both with water and without water for circular and rectangular water tanks. The different impact velocities considered in the present study were 50, 100, 200 and 400 kmph. The water tank is considered to be fixed at slab base. Due to the limitation on the maximum number of nodes in the academic version of ANSYS, finite element modelling of water tank has been carried out on a water tank of reduced capacity of 4400 L. The reduced tank has a height of 1.40 m and diameter as 2 m. The size of meshing is taken as 100 mm, and thickness of the base slab considered is 150 mm. Salient results such as total deformation, principal stresses, equivalent stresses, normal stresses and the directional deformation for both circular and rectangular tanks with water and without water cases for the different velocities were obtained. The comparison of the various results for the different cases was detailed. It is observed that with the use of finite element simulation, one can come to an optimized shape of the tank with least amount of internal stresses developed within. Keywords Finite element · Water tank · Reinforced concrete · Impact velocity · Explicit analysis · ANSYS

1 Introduction Concrete structures in the past were not designed for impact load in a direct manner, but indirectly it was dealt using partial safety factors, etc. Structures behave very differently when it is subjected to impact loads than that of static loads. Impact load is the one which is applied over a very short duration. This is most important in the case of vehicle impact on the structure, marine structures experiencing impact forces P. Ganesan (B) · M. V. A. N. Jagadeesh Babu · M. Nizamuddin · T. Sai Ram Kiran Department of Civil Engineering, MVGR College of Engineering, Vizianagaram 535005, India e-mail: [email protected] © Springer Nature Singapore Pte Ltd. 2020 S. Adhikari et al. (eds.), Advances in Structural Engineering and Rehabilitation, Lecture Notes in Civil Engineering 38, https://doi.org/10.1007/978-981-13-7615-3_10

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due to ice, and sudden explosions and so forth. Impact analysis of liquid retaining structures such as water tank, chemical storage tank and petroleum storage tank is very important as it involves lives of so many people in addition to the huge amount of investment on resources in building these structures. Elevated water tanks are one of the prime basic necessities of any city to distribute water to all possible location. Generally, circular tanks are used for large capacity. For tanks of smaller capacity, the cost of shuttering for circular tanks becomes high. Therefore, rectangular tanks can be used in such circumstances. Jhung et al. [1] found that there is a little difference between the initial velocity and impact force application for the impact analysis of ANSYS. Fluid can be a significant factor in terms of their capacity to absorb the response of the tank due to the impact. Ren et al. [2] investigated the projectile impact on water-filled aluminium alloy tank with different shapes of projectile to see the deformation and strain characteristics of target panel. Meanwhile, other researchers [3, 4] studied the performance of water tank under blast loading by the way of conducting numerical studies. Their study showed that water can significantly reduce the response of water tank under blast loading through reducing the external work. Whereas the literature [5] shows the impact performance of explosively formed projectile on the concrete targets, and the same was modelled through LS-DYNA software. Another research [6] focused on projectile–target interactions and explains how the decay of projectile velocity is related to the initial conditions of the target. The experimental and computational results of a steel sphere impacting a water-filled cylinder were presented in [7]. The focus of the research was on the measurement of shock loading in water with different gage designs.

2 Finite Element Modelling of Water Tank Water tank was designed for a standard capacity as per the design procedure laid down in IS: 3370-2009 (Part-2) [8]. The finite element simulation was carried out using freely available ANSYS academic version. Due to the limitation in number of nodes in ANSYS academic version, the scaled-down model is used for performing the analysis.

2.1 Geometry Details Circular Tank The circular tank modelled in this study has an internal diameter 2 m and a height of 1.40 m. Thickness of both the base slab and the walls is 150 mm. The impactor has a nose radius of 175 mm. The base slab is provided with 10-mm-diameter bars at a spacing of 150 mm centre to centre in both the directions. The inner and outer

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Fig. 1 Circular tank modelled in ANSYS

Fig. 2 Reinforcement modelling in ANSYS

vertical bars in the walls also have a reinforcement of 10 mm diameter placed at 150 mm centre to centre along the circumference. The same reinforcement has been provided as the inner and outer rings in the wall. Figures 1 and 2 show the water tank and the reinforcements, respectively. Square tank The square tank studied is of size 1.772 m × 1.772 m, which has a height of 1.40 m and wall thickness as 150 mm. The base slab was of 150 mm thickness. The reinforcement details are same as that used in circular tank.

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Fig. 3 Impactor used in the study

Table 1 Different parts involved in finite element modelling

Body

Material

Stiffness behaviour

Walls and base slab

M30 concrete

Flexible

Reinforcements

Fe415

Flexible

Impactor

Fe415

Rigid

Water

Liquid

Flexible

Impactor Impactor used in the study to give impact force was created by drawing a rectangle and arc revolved through 360° as shown in Fig. 3.

2.2 Material Modelling The material properties of relevant materials used in this study are summarized in Table 1. Concrete The concrete walls and base slab were assigned with the elastic properties such as Young’s modulus and Poisson’s ratio, and the plastic properties were given in multilinear isotropic hardening model by using the stress–strain curve suggested by Hognestad et al. [9]. It is presented in Fig. 4. Reinforcement The reinforcement bars were assigned with the elastic properties such as Young’s modulus (200 GPa) and Poisson’s ratio (0.30), and the plastic properties were given in multilinear isotropic hardening model as shown in Fig. 5 by using the stress–strain curve suggested by IS 456-2000 [10]. The impactor was assigned with same properties as the reinforcement except that this is made rigid by the way of increasing Young’s modulus value.

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Fig. 4 Stress–plastic strain curve of concrete used in modelling

Fig. 5 Stress–plastic strain curve of reinforcement bars used in modelling

2.3 Finite Element Modelling The finite element mesh of circular tank and the rectangular tank is shown in Figs. 6 and 7. The element type was solid Hexahedral. The size of the mesh taken is 100 mm. Contact “Reinforcement body interaction” type was assigned for all steel bars to attach to them with the concrete so as to act as an integral unit. And frictional contact has been given between bullet and concrete. Bullet was modelled as a rigid body; remaining all bodies were in flexible behaviour.

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Fig. 6 Finite element mesh of circular tank with water

Fig. 7 Finite element mesh of square tank with water

Boundary Conditions In the finite element analysis of water tank, in all the models, the base slabs are fixed at the bottom. The impactor is given an impact velocity in the direction normal to the surface of the water tank. Impact velocity The impact velocity considered in this study is 50, 100, 200 and 400 kmph. For each and every velocity, the finite element analysis of all the models was performed using explicit dynamics. The end time for the velocity is taken 0.001 s. Different Models The following four different cases were studied using finite element explicit dynamics using ANSYS Workbench platform: a. b. c. d.

Circular tank without water Circular tank with water Square tank without water Square tank with water

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3 Results and Discussion 3.1 Circular Water Tank Analysis of circular water tank without water subjected to impactor with different velocities is presented in Table 2. It is observed from Table 2 that as the impact velocity of the impactor increased gradually, the directional deformation values also kept increasing though not proportionately. For an impact velocity of 50 kmph, the deformation was 13.89 mm, whereas when the impact velocity was 400 kmph (8 times the first velocity), the tank has undergone a deflection of 146 mm (10.5 times the deformation corresponding to 50 kmph velocity). Consequently, the normal stress in the tank has reduced from 58.245 MPa at 50 kmph to mere 31.52 MPa at the velocity of 400 kmph. The impact force and the corresponding energy also presented for various impact velocities. The directional deflection contour of the bisected tank is shown in Fig. 8 for the better clarity on the results. This deflection contour is for the impact velocity of 400 kmph.

Table 2 Results of circular tank without water subjected to different impact velocities S. No.

Velocity (kmph)

Directional deformation (mm)

Normal stress (MPa) 58.24

1

50

13.89

2

100

28.02

3

200

70.338

4

400

146

31.51

Energy (kN m)

Impact force (kN)

13.98

1006

46.07

55.94

1996

39.22

223.78

3182

895.12

6131

Fig. 8 Directional deformation of empty circular water tank

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Fig. 9 Contour of maximum principal stress of empty water tank

Fig. 10 Equivalent stress contour of empty water tank

Similarly, the contours such as equivalent stress and maximum principal stress are all obtained and are presented for the empty circular water tank subjected to an impact velocity of 400 kmph as in Figs. 9 and 10. It is observed from the above figures that when the tank is subjected to impact forces, the effect of the impact is very much localized. The deformation at the point where the impactor in contact with the tank is maximum, whereas the deflection just away from the circumference of the impactor is not as much or minimal. It is also

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Fig. 11 Deformation of reinforcement bars when subjected to impact (V = 400 kmph) Table 3 Results of circular tank with water subjected to different impact velocities S. No.

Velocity (kmph)

Directional deformation (mm)

Normal stress (MPa)

1

50

13.89

62.50

2

100

29.17

3

200

72.11

4

400

148.31

Energy (kN m)

Impact force (kN)

13.98

1006

51.50

55.94

1917

47.39

223.78

3103

50.48

895.12

6035

due to the fact that the concrete is brittle material as opposed to some of the tank made of alloys. Also, the directional deformation in the reinforcement is also presented in Fig. 11 It is very clearly observed that the damage due to the impact is localized. Similarly, explicit analysis was performed for the circular tank with water for different impact velocities. The results for the same are presented in Table 3. It is observed from Table 2 and also from Table 3 that the directional deformation values are almost same. It is due to the fact that the damage is very local. However, the normal stresses in the empty circular tank are decreased by 6–37.50% for the impact velocity 50–400 kmph in the case where the tank is full. It is due to the fact that the constraint exerted by the water increases the stresses in the wall.

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3.2 Square Water Tank In order to ascertain the effect of shape of the water tank subjected impact velocity, square tank of same capacity is also designed in addition to circular shape tank, and the tank was analysed for the various impact velocities as in circular tank. The results for the same are presented in the following section for the directional deformation, normal stress and so on. Table 4 shows the comparison of results obtained for empty and water full square tank. It is observed from the above table that the pattern of results for various impact velocities is same as that of circular tank. Figure 12 shows the normal stress contour on water-filled square tank when it is impacted by the impactor with the velocity of 400 kmph. Figure 13 shows the equivalent stress of square tank subjected to impact velocity of 400 kmph. The tank is cut through the middle to show the effect of stress distribution through the thickness. Table 5 shows the comparison of directional deformation and the normal stress values of circular and square tank for different velocities for the empty tank. It is observed from Table 5 that for the lower velocity up to 100 kmph, the directional deformations and normal stresses in the square tank are less than that of circular tank. It may be due to the reason that in the square tank, due to the less constraint, the deformation is spread over larger area than the circular tank, whereas for the higher velocities, the deformation and normal stresses are almost in both the cases due to localized effect.

Table 4 Comparison of results on impact on square tank for different velocities S. No.

Velocity (kmph)

Directional deformation (mm)

With water

DeformationNormal stress (MPa) comparison with filled tank (%)

Without water

With water

Without water

Stress comparison with filled tank (%)

1

50

13.889

13.889

Same

52.259

43.631

Decreased by 16.51

2

100

29.223

27.778

Decreased 46.865 by 4.944

41.798

Decreased by 10.81

3

200

70.825

68.482

Decreased 48.285 by 3.308

39.851

Decreased by 17.46

4

400

Decreased 58.921 by 1.93

43.87

Decreased by 25.54

144.5

141.71

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Fig. 12 Normal stress contour of square tank with water subjected to impact

Fig. 13 Equivalent stress contour of square tank with water subjected to impact

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Table 5 Effect of shape of tank to impact S. No.

Velocity (kmph)

Empty tank Circular tank Directional deformation (mm)

Square tank Normal stress (MPa)

Directional deformation (mm)

Normal stress (MPa)

1

50

13.89

58.24

13.88

43.63

2

100

28.02

46.07

27.77

41.79

3

200

70.32

39.22

68.48

39.85

4

400

146.00

31.51

141.71

43.87

4 Conclusions It is observed from the present study that finite element simulation can be effectively used in the study of the impact of objects on water tank without having to perform actual destructive testing which involves a lot of resources such as water and materials. It is noticed from the present study that, since the impactor size is very small compared to that of the tank, the effect of the impact in most cases is local. Also, using finite element simulations, other shapes which are effective to impact can be designed, which reduce the cost to a greater extent if it has to be done other ways.

References 1. Jhung MJ, Jo JC, Jeong SJ (2006) Impact analysis of a water storage tank. Nucl Eng Technol 38(7):681–688 2. Ren P, Zhou J, Tian A, Ye R, Zhang W (2018) Experimental investigation on dynamic failure of water-filled vessel subjected to projectile impact. Int J Impact Eng 117:153–163. https://doi. org/10.1016/j.ijimpeng.2018.03.009 3. Wang Y, Zhou H (2015) Numerical study of water tank under blast loading. Thin-Walled Struct 90:42–48. https://doi.org/10.1016/j.tws.2015.01.012 4. Wang Y, Xiong M-X (2015) Analysis of axially restrained water storage tank under blast loading. Int J Impact Eng 86:167–178. https://doi.org/10.1016/j.ijimpeng.2015.07.012 5. Abrate S (2014) Impact on composite plates in contact with water. Procedia Eng 88:2–9. https:// doi.org/10.1016/j.proeng.2014.11.119 6. Lecysyn N, Dandrieux A, Heymes F, Slangen P, Dusserre G (2008) Preliminary study of ballistic impact on an industrial tank: Projectile velocity decay. J Loss Prev Process Ind 21(6):627–634. https://doi.org/10.1016/j.jlp.2008.06.006 7. Hopson MV, Treadway SK (2008) Testing and computational analysis of pressure transducers in water filled tank impacted by hypervelocity projectile. Int J Impact Eng 35(12):1593–1601. https://doi.org/10.1016/j.ijimpeng.2008.07.079 8. Indian Standard-3370-2009 (Part 2) (2009) Concrete structures for storage of liquids—code of practice-part 2 reinforced concrete structures, Bureau of Indian Standards, New Delhi 9. Hognestad E, Hanson NW, McHenry D (1956) Stress distribution in ultimate strength design. J Am Concr Inst J Proc 52:1305–1330 10. Indian Standard-456 (2000) Plain and reinforced concrete code of practice, Bureau of Indian Standards, New Delhi, 2000

Mix Design and Factors Affecting Strength of Pervious Concrete Bishnu Kant Shukla and Aakash Gupta

Abstract Pervious concrete is a sure sort of concrete with a high porosity utilized for concrete flatwork applications that will permit the water from precipitation and different sources to go straightforwardly through, along these lines diminishes the overflow from a site and permitting groundwater to revive. The concrete glue at that point coats the totals and enables water to go through the concrete piece. With interconnected void content, we can achieve high porosity. Water-to-cementitious material ratio is 0.40–0.50. Designs were made at different water–cement ratios, and these ratios show the different exposure conditions. In this paper, specific gravity of cement, coarse aggregate and fine aggregate were selected as 3.15, 2.68, 2.65 respectively. Cement used in this project was OPC-43. Coarse aggregate were used at different proportions. The present examination tended to the strength and seepage parts of pervious concrete mix and furthermore the impact of CS as FA. A pointby-point contemplate is required to know the impacts of total degree with different kinds of total. In this undertaking, the mechanical properties of pervious concrete have been used to plan road pavements. The properties of PCC blend to be examined are compressive strenth and flexural strength. An optimum percentage has been determined which shows the concrete is permeable and having good compressive and flexural strength. In this research paper, the mechanical properties of pervious concrete have been used to design road pavements. Main focus of the paper is to determine and improve compressive strength, and flexural strength. Keywords Pervious concrete · OPC · NFC · FA · CA · River sand · Crushed stone

B. K. Shukla Lovely Professional University, Phagwara, India e-mail: [email protected] A. Gupta (B) Jaypee University of Information Technology, Waknaghat, India e-mail: [email protected] © Springer Nature Singapore Pte Ltd. 2020 S. Adhikari et al. (eds.), Advances in Structural Engineering and Rehabilitation, Lecture Notes in Civil Engineering 38, https://doi.org/10.1007/978-981-13-7615-3_11

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1 Introduction Porous concrete is a blend of shake or stone, bond, water and alongside zero FA which influences an open cell for structure which further then empowers water and air to experience it. According to the environmental protection agency (EPA), storm water flood can send as much of 90% toxic substance, for instance, oil and other hydrocarbons. The limit of porous concrete to empower water to travel through itself resuscitates and after that groundwater restricts the level of defilement and whirlwind water overflow. Porous cement is used to allow storm water to attack through the black-top and diminish or shed the necessity for the additional control structures, for instance, support lakes. The pervious solid black-top has various ideal conditions that can improve the city condition as takes after: 1. The water can quickly channel into the ground, so the groundwater resources can re-establish in time as the black-top is air permeable, water vulnerable and the soil underneath can be kept wet. 2. The porous solid black-top can hold the commotion of vehicles, which influences peaceful and pleasant to condition. 3. In tempestuous days, the pervious solid black-top has no plash at first look and does not flash around night time. This will improve the comfort and prosperity of the drivers. 4. The pervious solid black-top materials have openings that can cumulate warm. Such black-top can change the temperature and suddenness’ of the earth’s surface and gets rid of the wonder of hot island in urban zones. An achieved installer is irreplaceable to the accomplishment of pervious solid black-tops as with any solid black-top, fitting subgrade status is crucial [1]. The subgrade should be properly compacted for reason that it will give a uniform and stable surface. Right when pervious black-top is set direct on the sandy soil, then it is recommended to moderate the subgrade from 92 to 96% of the most extraordinary thickness. With the silty or clayey soils, the level of compaction will tons of black-top arrangement and a layer open assessed stone may must be put over soil. The voids can go from 18 to 35% with compressive strength of 10–30 MPa. The invasion rate of pervious cementitious materials, coarse totals, water with practically no fine aggregates and admixtures. The expansion of little measures of fine totals will continuously lessen the void space and increment the strength, which might be attractive in specific circumstances. This material is touchy to change in water content, so field modification of crisp blend is typically important. The right amount of water in the solid is basic. An excess of water will cause isolation, and too little water will prompt balling in the blender and moderate blender emptying. The W/C and C/A proportions are regularly varied from 0.25 to 0.45 and 1:3.5 to 1:6. To make a porous solid structure with ideal porousness and compressive strength, the measure of water, measure of bond, sort and size of aggregate, and compaction should all be considered. A colossal number of examinations have been now driven all through the past couple of

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decades by an assortment of specialists contrasting a few or these components. In his paper [2], V. M. Malhotra discussed pervious concrete as it relates to applications and properties. He gave purposes of enthusiasm on the properties such as consistency, extents of materials, unit weight, comparability and curing endeavouring to open up penetrability in the porous cement. Malhotra also drove various investigations on different test chambers endeavouring to find a connection between strength like compressive strength and any of the material’s properties. He gathered for the compressive nature of pervious cement was reliant on the water bond proportion and the total concrete ratio. Attractive vibration is essential for nature of customary cement. The use of porous cement is one of a kind and is a self-pressing item. It was recommended by several researchers [2–6] that the use of mechanical vibrators and smashing is not proposed with porous cement. A light rodding should be attractive and used to ensure that the solid accomplishes all regions of the formwork. This is not an issue with customary cement, since it has more prominent stream capacity than penetrable cement. The light rodding ensures that the solid entered every region obstructed by fortifying steel. Malhotra [2] stressed that in circumstances where common conditions are not refined amid arrangement and curing, the formwork ought not to be expelled following 24 h as with normal cement. Permeable cement has low cohesiveness and formwork ought to stay until the point that the bond glue has solidified adequately to hold the total particles together. Be that as it may, this is to a greater degree a thought in low temperature conditions and when utilized as a part of non-asphalt applications where the concrete is not adequately upheld by the ground or different means. Another recent work on Portland cement concrete pavement permeability execution [7] expresses test ponders on transport properties of concrete are controlled by the attributes of its pore arrange. Add up to porosity, pore size, pore connectivity, and pore saturation, all impact the deliberate transport coefficients [7]. Water-absorbing concrete was first utilized as a part of the 1800s in Europe as pavement surfacing and load-bearing walls. Cost-effectiveness was the principle thought process because of a diminished measure of cement. It ended up prominent again in the 1920s for two story homes in Scotland and England. It turned out to be progressively suitable in Europe after WWII because of the shortage of cement. It did not move towards becoming as well known in the USA until the 1970s. In India, it ended up well known in 2000. The first water-absorbing placement in the Indian metro area was in Sugar Creek, MO in November 2005. Since that time, around 30+ pavements have been put and numerous lessons found out about what makes water-absorbing concrete ‘great‘. Here in, are the present rules that have been educated and adjusted. Shah et al. [8], in his work on water-absorbing concrete examined on utilizing pervious concrete as street development material generally new idea for provincial street pavement, with expanding issue in country zones identified with low groundwater level, farming issue. His report centres around pavement utilization of concrete which additionally has been referred on pervious concrete, penetrable concrete, no fine concrete, hole-reviewed concrete and upgraded porosity concrete. As a result of work on water-absorbing concrete, Eathakoti et al. [1] developed an innovative model that can transport water go into the pavement has been proposed

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towards this path. Diverse mixes of cement, water and coarse aggregate with various greatest size and gradation were adopted for mixing procedure to make roughly at M20 grade concrete. M20 grade concrete is accomplished with a w/c proportion of 0.4–0.45, coarse aggregate of nominal size 20 mm and with cement to coarse aggregate proportion of 1:4. Its density and flexural strength quality were seen to be 21 kN/m3 and 35 kg/cm2 individually. A pavement piece appropriate for low activity volume streets is planned according to IRC SP62: 2004 which permits stockpiling of water up to 125 L/m3 of concrete pavement giving time for invasion in this way diminishing the runoff and reviving the groundwater or adequate time for transport of it. A perforated pipe can be given at focus of the pavement above sub-base with the end goal that it gathers the water put away in concrete and depletes it to the required treatment plant or a fill pit [9, 10]. This, however, needs to encourage examination and trials before practical implementation [11]. Aims and objectives of the present work are: 1. The principle target of this examination is to build up a solid and tough pervious bond concrete (PCC) blend utilizing distinctive kinds of FA with changing the amount of FA. Moreover, it is likewise expected to think about the properties of these PCC blends. 2. The level of fine aggregates to be utilized as a part of PCC blend is set to 30% max. 3. The properties of PCC mixes to be looked into are compressive quality and flexural quality.

2 Methodology After distinguishing proof of issue and setting the targets of the research, the research methodology has been carefully designed to accomplish these destinations. 1. Accumulation and investigation of writing relating to the exposition work. 2. Decide the building properties of porous concrete and compare them with ordinary concrete. Cast different trial blends with changing rates of porous concrete and analyse for the compressive strength. 3. Get-ready test tests with the rate esteem and tests the examples for the different properties. 4. To remark on the reasonableness and confinements of porous concrete with traditional concrete.

2.1 Planning Schedule Collections of material were carried out as per the following schedule: 1. Collection of OPC Cement 2. Preparation of mould for casting of cubes and beams

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3. Collection of CA and FA. Commercially available CA and FA were collected, and suitable percentages of both the aggregates were fixed. For example, NFA, 4:1, 3:2. Mixes were created by varying cement content from 350 to 480 kg/m3 . Sets of three cubes were casted having different mix proportions. After 24 h of casting, cubes were demoulded and water cured for several days. Each set of cubes were tested for mechanical properties at the end of 3, 7 and 28 days.

2.2 Casting and Testing After making the mix design at three different cement contents, i.e. 479, 446, 384 kg/m3 and without taking fine aggregates, with coarse aggregate to fine aggregate ratio as 5:0, the mix design with lowest concrete density has been selected. The cement content of 384 kg/m3 has the lowest concrete density; therefore, further two more mix proportions prepared using ratio 4:1 and 3:2 of coarse aggregate and fine aggregate. Mix proportions for casting of cubes and beams have been shown in Tables 1, 2, 3, 4, 5 and 6.

Table 1 Mix proportion for cube using no fine aggregate at cement content 384 kg/m3 (w/c = 0.50) (CA:FA = 5:0) S. No.

Material

Quantity per m3 (kg)

Quantity for casting one cube (150 * 150 * 150 mm) (kg/mm3 )

1

Cement

384

1.296

2

Water

191.6

0.6466

3

CA

1839.82

6.2093

4

FA

Nil

Nil

5

Yield

2415.42

8.1519

Table 2 Mix proportion for cube using fine aggregate at cement content 384 kg/m3 (w/c = 0.50) (CA:FA = 4:1) S. No.

Material

Quantity per m3 (kg)

Quantity for casting one cube (150 * 150 * 150 mm) (kg/mm3 )

1

Cement

384

1.296

2

Water

191.6

0.6466

3

CA

1471.856

4.967

4

FA

363.845

1.2279

5

Yield

2411.3

8.1375

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Table 3 Mix proportion for cube using fine aggregate at cement content 384 kg/m3 (w/c = 0.50) (CA:FA = 3:2) S. No.

Material

Quantity per m3 (kg)

Quantity for casting one cube (150 * 150 * 150 mm) (kg/mm3 )

1

Cement

384

1.296

2

Water

191.6

0.6466

3

CA

1103.89

3.7256

4

FA

727.69

2.4559

5

Yield

2407.18

8.1241

Table 4 Mix proportion for beam using no fine aggregate at cement content 384 kg/m3 (w/c = 0.50) (CA:FA = 5:0) S. No.

Material

Quantity per m3 (kg)

Quantity for casting one beam (100 * 100 * 500 mm) (kg/mm3 )

1

Cement

384

1.92

2

Water

191.6

0.958

3

CA

1839.82

9.1991

4

FA

Nil

Nil

5

Yield

2415.42

12.077

Table 5 Mix proportion for beam using fine aggregate at cement content 384 kg/m3 (w/c = 0.50) (CA:FA = 4:1) S. No.

Material

Quantity per m3 (kg)

Quantity for casting one beam (100 * 100 * 500 mm) (kg/mm3 )

1

Cement

384

1.92

2

Water

191.6

0.958

3

CA

1471.856

7.359

4

FA

363.845

5

Yield

2411.3

1.8192 12.056

Table 6 Mix proportion for beam using fine aggregate at cement content 384 kg/m3 (w/c = 0.50) (CA:FA = 3:2) S. No.

Material

Quantity per m3 (kg)

Quantity for casting one beam (100 * 100 * 500 mm) (kg/mm3 )

1

Cement

384

1.92

2

Water

191.6

0.958

3

CA

1103.89

5.519

4

FA

727.69

3.638

5

Yield

2407.18

12.035

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Fig. 1 Surface cleaned and oiled moulds

2.3 Size of Test Specimens Test specimens cubical in shape was 15 cm × 15 cm × 15 cm. If the largest nominal size of the aggregate does not exceed 2 cm, 10-cm cubes may be used as an alternative. Similarly for beams, the size of moulds used was 50 cm × 10 cm × 10 cm. Cubes were casted to perform check on compressive strength of pervious concrete while beams were casted to check the flexural strength of pervious concrete.

2.4 Preparation of Moulds Prior to mixing and casting of specimen, one of the most important and timeconsuming works is the preparation of moulds [12]. Moulds were prepared such that all surfaces of moulds were cleaned and oiled properly, and all the bolts were tightened so that it did not allow any leakage of mortar (Fig. 1). Special care was taken while applying oil. Excessive amount of oil can lead to the presence of bug holes on the surface of concrete after demoulding. A suitable brush or cloth was used while applying oil on the surface of moulds. Also, type of oil used is very important as the purpose of oil is to provide necessary lubrication so that concrete may not stick to the surface of moulds and it should be easy to demould the specimen. If suitable oil is not used, then it may break your specimens and whole procedure is to be repeated again. The oil used in this study was waste black oil easily available at any workshop at no cost or very minimal charges.

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Fig. 2 Homogeneous dry mix

Fig. 3 Homogeneous wet mix after adding water

2.5 Mixing All of the mixing of concrete was done by hand mixing only. All of the ingredients of pervious concrete like cement, coarse aggregate and fine aggregate were first weighed as per mix design proportion and then mixed on floor which was prepared for saturated surface dry condition so that floor shall not absorb any water from the mix neither shall it release more water into the mix. All three ingredients of pervious concrete were first mixed in dry condition (Fig. 2) so that all aggregates were properly mixed with cement in order to have homogeneous mixture (Fig. 3). After the mixing of concrete, well-cleaned and oiled moulds were filled with concrete and hand compacted. Here, table vibrator is not recommended as it was noted that under effect of vibration cement slurry settles down and makes the concrete impervious. Each mould was filled in three layers and hand compacted after each layer with the help of tamping road.

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Fig. 4 Specimen kept for 24 h prior to demoulding

Again, after the moulds were filled with concrete and leveled, the specimens were left for 24 h before demoulding (Fig. 4) so that concrete achieves its hardening. After 24 h of casting, the cubes were demoulded on very next day without any delay.

2.6 Testing of Specimens The entire specimens were tested as per directions given in IS 516 (1959). To check compressive strength of concrete using pervious concrete cubes, compression testing machine was used, whereas to perform check on flexural strength of beams, flexural testing machine was used. The load for compression testing machine was set as specified in IS 516, i.e. 140 kg/cm2 /min. The load shall be applied slowly without shock and increased continuously until the resistance of specimen (concrete cube) to increasing load breaks. Calculation of Load: Load as per IS Code = 140 kg/cm2 /min 1 kg = 9.81 N 1000 N = 1 kN 1 min = 60 s But load specified in IS 516 is in kg/cm2 /min = (1.373 × 15 × 15)/60 = 5.148 kN/s

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Similarly, for flexural strength test, load specified in IS 516 = 180 kg/min for 10-cm beams that comes out to be 29.42 N/s.

3 Results and Discussion The results of the study have been presented under the following heads.

3.1 Compressive Strength Results Compressive strength results were determined after 3, 7 and 28 days of curing and presented in Tables 7, 8 and 9.

Table 7 Compressive strength of cubes using no fine aggregates (CA:FA = 5:0)

Table 8 Compressive strength of cube using fine aggregates (CA:FA = 4:1)

S. No.

Age of cube (days)

Compressive strength of cube (MPa)

1

3

6.9

2

3

7.6

3

3

7.4

4

7

8.2

5

7

8.8

6

7

9.4

7

28

10.55

8

28

11.3

9

28

11.9

S. No.

Age of cube (days)

Compressive strength of cube (MPa)

1

3

8.53

2

3

8.88

3

3

8.1

4

7

11.87

5

7

11.82

6

7

12.88

7

28

13.55

8

28

15.7

9

28

16.66

Mix Design and Factors Affecting Strength of Pervious Concrete Table 9 Compressive strength of cube using fine aggregates (CA:FA = 3:2)

Table 10 Flexural strength of beams using no fine aggregates (CA:FA = 5:0)

Table 11 Flexural strength of beams using fine aggregates (CA:FA = 4:1)

S. No.

Age of cube (days)

135

Compressive strength of cube (MPa)

1

3

18

2

3

17.82

3

3

18.1

4

7

33.64

5

7

32.26

6

7

33.82

7

28

42.04

8

28

41.91

9

28

41.56

S. No.

Age of beam (days)

Compressive strength of beam (MPa)

1

7

2.76

2

7

2.73

3

7

3

4

28

2.99

5

28

3.26

6

28

3.5

S. No.

Age of beam (days)

Compressive strength of beam (MPa)

1

7

4

2

7

3.25

3

7

3

4

28

4.2

5

28

4.3

6

28

3.9

3.2 Flexural Strength Results Flexural strength results were determined after 7 and 28 days of curing and presented in Tables 10, 11 and 12. Figure 5 shows a comparative study of compressive strengths after 3, 7 and 28 days for sample 1, sample 2 and sample 3. It was noticed that compressive strength increases from sample 1 to sample 3 with sample 3 showing highest compressive strength and sample 1 showing lowest compressive strength as compared to other

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Table 12 Flexural strength of beams using fine aggregates (CA:FA = 3:2) S. No.

Age of beam (days)

Compressive strength of beam (MPa)

7

4.6

2

7

4.5

3

7

4

4

28

6

5

28

5.75

6

28

5

Average compressive strength (Mpa)

1

45 40

3-days strength

35

7-days strength

30

28-days strength

25 20 15 10 5 0

3-days strength 7-days strength 28-days strength

Sample1(CA:FA=5:0) 7.3 8.8 11.25

Sample2(CA:FA=4:1) 8.5 12.19 15.3

Sample3(CA:FA=3:2) 17.97 33.24 41.84

Fig. 5 Comparison of average compressive strength of cubes with different CA:FA ratios

two samples, but sample 2 having higher compressive strength than sample 1 and lower compressive strength than sample 3. Figure 6 shows a comparative study of flexural strengths after 7 and 28 days for sample 1, sample 2 and sample 3 which shows that flexural strength increases from sample 1 to sample 3. Sample 3 demonstrated higher flexural strength as compared to the other two samples while sample 1 showing the lowest flexural strength .

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Flexural strength (MPa)

45 40

7-days strength

35

28-days strength

30 25 20 15 10 5 0

7-days strength 28-days strength

Sample1(CA:FA=5:0) 8.8 11.25

Sample2(CA:FA=4:1) 12.19 15.3

Sample3(CA:FA=3:2) 33.24 41.84

Fig. 6 Comparison of average flexural strengths of beams with different CA:FA ratios

3.3 Discussion of Results Compressive Strength: It was established as a result of experimental observations that the 3-day strength of specimen increases in the compressive strength of M20 grade (from ratio 5:0 to 3:2 of CA:FA) of pervious concrete by 13.8%, whereas an increase in the compressive strength of M20 grade (from ratio 5:0 to 3:2 of CA:FA) of pervious concrete was seen by 25.9% in case of 7-day strength. On the other hand, the rise in 28-day compressive strength was observed to be 54.8% From the results, it was concluded that compressive strength increases from ratio 5:0 to 3:2 of coarse aggregate and fine aggregate. Compressive strength of pervious concrete is lower than of conventional concrete. At the CA:FA ratio 4:1, sample shows very good porosity and good compressive strength. Strength also increases from 3 days to 28 days. It means strength is directly proportional to time. Flexural Strength: As a result of experimental observations, an increase of 10.7% was observed in the 7-day flexural strength of M20 grade (from ratio 5:0 to 3:2 of CA:FA), whereas the increase in 28-day flexural strength of the sample was found to be 21.4%. From the flexural strength results, it was concluded that flexural strength increases from ratio 5:0 to 3:2 of coarse aggregate and fine aggregate. Flexural strength of pervious concrete is lower than of conventional concrete. At ratio 4:1, sample shows the porosity and good flexural strength. Strength also increases from 3 days to 28 days, which means that flexural strength increases with time.

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4 Conclusions From this study, several conclusions were made to successfully develop pervious concrete of desired physical and mechanical properties • Content of cement is a very important aspect to be considered while designing pervious concrete. Excessive amount of cement will form cement slurry when mixed with water and will settle down after the concrete has been placed into the moulds, thereby making the base of concrete impervious. • It was also found that as the mixture is unable to retain/hold water while mixing therefore concrete mixer is recommended for heavy concreting. However for small scale work in laboratory, steel or iron mixing tray can be used in order to avoid loss of water. • Table vibrator or any other vibratory compaction method shall not be used while compacting pervious concrete as vibration leads to gravitational settlement of cement slurry again making the base of specimen impervious. Only hand compaction is recommended as per this study. • While oiling the cubes, excessive oil should be prevented on the surface of moulds as it leads to the formation of bug holes on the surface of concrete cubes. Type of oil used should be checked for its lubricating properties. Oil should not be sticky rather it should be oily. Motor vehicle black oil is recommended in this study. • Out of three different mixes on different proportions of cement, i.e. 479, 446 and 384 kg/m3 it was found that specimens having cement quantity as 384 kg/m3 had greater permeability. • Three different mixes were prepared having cement content as 384 kg/m3 of cement—Mix 1 having 0% sand, Mix 2 having 15.02% sand and Mix 3 having 30.22% sand. It was found that the first two mixes had good permeability, while the third mix was impermeable. Out of the first two mixes, second mix is recommended as it had considerable permeability and good compressive strength as compared to Mix 1 specimens. • Lastly, it was concluded that the proportion of fine aggregate can be used in development of pervious concrete not exceeding 15% in proportion of mix by weight.

References 1. Eathakoti S, Gundu N, Ponnada MR (2015) An innovative no-fines concrete pavement model. IOSR J Mech Civ Eng IOSR-JMCE 12(3):34–44 2. Malhotra VM (1976) No-fines concrete-its properties and applications. Can Mines Branch Inf Circ IC 313, vol 73(11), pp 628–644 3. Teware PR, Harle SM (2016) Mix proportion of cementitious material in pervious concrete. J Recent Act Archit Sci 1(3):1–13 4. Shah DS, Pitroda J, Bhavsar JJ (2013) Pervious concrete: new era for rural road pavement. Int J Eng Trends Technol 4(8):3495–3499 5. Nishikant K, Nachiket A, Avadhut I, Sangar A (2016) Manufacturing of concrete paving block by using waste glass material. Int J Sci Res Publ 6(6):61–77

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6. Balaji MH, Amarnaath MR, Kavin RA, Jayapradeep S (2015) Design of eco friendly pervious concrete. Int J Civ Eng Technol IJCIET. ISSN 0976-6308 7. Castro J, Spragg R, Kompare P, Weiss WJ (2010) Portland cement concrete pavement permeability performance. Can Mines Branch Inf Circ IC 313, vol 73, pp 628–644 8. Pitroda J, Umrigar DF, Principal B, Anand GI (2013) Evaluation of sorptivity and water absorption of concrete with partial replacement of cement by thermal industry waste (Fly Ash). Int J Eng Innov Technol IJEIT 2(7):245–249 9. Mageswari M (2016) High strength permeable pavement using no fines concrete. Int J Civ Eng (SSRG-IJCE) 3(3):53–57 10. Patil VR, Gupta AK, Desai DB (2010) Use of pervious concrete in construction of pavement for improving their performance. IOSR J Mech Civ Eng (IOSR-JMCE) 54–56 11. Nataraja MC, Das L (2010) Concrete mix proportioning as per IS 10262: 2009—comparison with IS 10262: 1982 and ACI 211.1-91. Indian Concr J 64–70 12. Dierkes C, Kuhlmann L, Kandasamy J, Angelis G (2002) Pollution retention capability and maintenance of permeable pavements. In: The proceedings of global solutions for urban drainage, pp 1–13

Effects of Change of Material Grade on Building Design J. Bhattacharjee, Abhishek Payal, Vikrant Jain and Adil Ahmed

Abstract The standard target of this research paper is to break down and outline a multistoried building [G+10] (three-dimensional frame) utilizing AutoCAD and STAAD Pro and to observe the influence it has on the building execution when the grade of cement is changed. AutoCAD has an extremely intuitive UI which enables the clients to design their structure in 2D utilizing exceptionally fundamental charges. At that point out, the AutoCAD record was transferred to STAAD Pro. The scope includes stack estimations physically and breaking down the entire structure by STAAD Pro. The outline techniques utilized as a part of STAAD-Pro examination are limit state design adjusting to Indian Standard Code of Practice. STAAD Pro highlights a best in class UI, representation devices, capable of investigation and outline motors with cutting edge limited component and dynamic examination capacities. From previous literature works it has been observed that for investigation and configuration to perception and result check, STAAD Pro provides proper solution. At that point as indicated by the predefined criteria allotted, it analyses the structure and plans the individual elements with reinforcement details for RCC frame. We proceeded with our work with some more multistoried 2D and 3D outlines under different load cases. Our last research work was the best possible examination and plan of a G+10, 3-D RCC frame under different load cases. It clearly portrays that the adjustments in the concrete and steel amount with the difference in concrete grade ranging from M25 to M60 concrete.

J. Bhattacharjee (B) · A. Payal · V. Jain · A. Ahmed Amity University, Noida, UP, India e-mail: jb[email protected] A. Payal e-mail: [email protected] © Springer Nature Singapore Pte Ltd. 2020 S. Adhikari et al. (eds.), Advances in Structural Engineering and Rehabilitation, Lecture Notes in Civil Engineering 38, https://doi.org/10.1007/978-981-13-7615-3_12

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1 Software Used 1.1 Auto Cad This is an outline and documentation programming program that was established in 1982, 28 years prior. It is the most normally utilized bit of programming of its kind, and it is continually being upgraded and enhancing its product to meet the present needs of its clients. It is utilized for attracting articles to a high level of accuracy in either 2D or 3D design utilizing polar directions. Civil design, civil design 3D professional support data-specific objects facilitating easy standard civil engineering calculations and representations.

1.2 STAAD Pro This is a limited component examination and plan programming program keep running on windows working frameworks, which is utilized to dissect the basic solidness of structures, under varities of conditions. It enables the clients to adequately break down structures worked from various distinctive materials, for example, timber, solid, aluminum and steel, under various powers caused by, seismic tremor, soil association, and different dead loads and live loads, which are indicated by the neighborhood configuration codes being utilized as a part of whatever area the structure is being outline, for this situation Euro codes.

2 Plan See Fig. 1.

3 Load Case Detail The ideas displayed in this section give an outline of building loads and their impact on the structural response typical wood-framed homes. As shown in table, building loads can be divided into types on the orientation of the structural action or forces that they induce: vertical and horizontal (i.e., lateral) loads. Classification of loads is depicted in the following section. Different types of loads on a building are as following: • Vertical load • Live load • Dead load

Effects of Change of Material Grade on Building Design

PLAN

Fig. 1 Floor plan of G+10 building

Fig. 2 Wind load

• • • •

Snow load Wind load Seismic and wind (overturning) Seismic (vertical ground motion) (Fig. 2).

143

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Fig. 3 Design load and design parameter for a doubly reinforced concrete beam Fig. 4 Graph representing the concrete required for each grade

Concrete Grade

Concrete(Cum)

1170.7 730.91 737.9 M25

M30

M40

737.9

737.9

M50

M60

4 Reinforcement Detail See Fig. 3.

5 Results Concrete Grade Concrete (Cum) See Figs. 4 and 5. From above graphs, we can clearly see that M40 concrete grade is the most suitable grade for the construction of G+10 floor building. Looking at the quantity if concrete requirement, steel and the cost, M40 is the most quality and cost-efficient grade of concrete.

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concrete Grade

Fig. 5 Graph giving the quantity of steel required

980363 M25

steel(in kg)

628871

614554

610195

608546

M30

M40

M50

M60

6 Conclusion The following inferences can be drawn, based on study made in this paper: • STAAD Pro can calculate the reinforcement need irrespective of the grade of concrete being used. The design contains predefined parameters with standard as per IS: 456 (2000) provision. • The optimum grade of concrete that is to be used in G+10 residential building constructions can be determined. • Cost-effective use of material can be determined, and unnecessary use of material can be avoided. • All load cases can be taken into consideration to calculate the reinforcement and concrete requirement with different grades. Acknowledgements This work was supported by Prof. (Dr.) J. Bhattacharjee. We would like to thank our faculty guide Prof. (Dr.) J. Bhattacharjee for helping us and providing us the necessary information when needed. We would like to thank the civil department of Amity University for giving us the opportunity to work on this particular project. It was a great experience and a learning process. I would also like to thank the civil engineering faculties for unhesitant help at any point of time.

References 1. 2. 3. 4. 5.

Dr. Karve SR, Dr. Shah VL Illustrated design of reinforced concrete buildings Krishna Raju N Advanced reinforced concrete design STAAD Pro 2004—Getting started and tutorials. Published By R.E.I STAAD Pro 2004—Technical reference manual. Published By R.E.I IS 875—Bureau of Indian Standards Manak Bhavan, 9 Bahadur Shah Zafar Marg New Delhi 110002 6. IS 456—Bureau of Indian Standards Manak Bhavan, 9 Bahadur Shah Zafar Marg New Delhi 110002

Feasibility of Redesigning and Retrofitting of a Structure for Vertical Expansion to Avoid Disasters J. Bhattacharjee, Kratika Sharma and Saahil Bader

Abstract The main aim of the study was to find out how the existing building can be further extended to meet the functional requirement, without demolition of the original building by using retrofitting techniques. The existing structure is a residential G+4-storied building of RCC framed structure . In order to find out the structural system of the building, the design was carried out for G+4-storied building with STAAD Pro software, since original design details of the structure were not readily available. Then, redesigning was done for G+7-storied structures to find out the revised details of column and beams mainly. There was a need for retrofitting of the structure to strengthen the structure for the safety of the structure. The scope of work consists of designing/redesigning of the structure to find out the revised section of the structural elements. To determine the requirement of retrofitting of the structure, revised design of structure with increased load was carried out for three additional vertical extensions of building and was find out the overall requirement of retrofitting, to avoid disasters . Keywords Retrofitting · Redesigning · Disasters · Hazards · Rehabilitation · Column jacketing

1 Introduction It is often seen that the purpose for which the building is designed may change over a period of time. Also, sometimes, the need is felt to expand the building vertically to meet functional requirement, i.e., to increase the number of stories of any building. J. Bhattacharjee (B) · K. Sharma · S. Bader Amity University, Noida, UP, India e-mail: [email protected] K. Sharma e-mail: [email protected] S. Bader e-mail: [email protected] © Springer Nature Singapore Pte Ltd. 2020 S. Adhikari et al. (eds.), Advances in Structural Engineering and Rehabilitation, Lecture Notes in Civil Engineering 38, https://doi.org/10.1007/978-981-13-7615-3_13

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Suppose as an example, a building is constructed as a residential tower, but due to any reason, it needs to be converted into an office complex. The loads in an office complex are much higher than that of a residential building. Or similarly, there can be a case when the numbers of floors need to be increased in order to cater to a larger number of people. This is seen especially in residential towers. The load of increased floors needs to be supported by the structure. In all these cases, total demolition of the building and reconstruction for the new purpose is definitely an uneconomical option. Another condition that needs to be taken care of is the revision of design codes. As our studies about the geotechnical, load-bearing, material and technical aspects of construction and seismic studies become more detailed, the design codes are getting revised from time to time. New provisions are included, and some old provisions may be changed or removed completely. The buildings that have already been designed and constructed before the revision of code may not be safe under the new revised provisions. It is again not sensible to demolish the building to incorporate the new provisions into design. The other aspects that are considered are not economical but the aspect of safety. There is a threat of a disaster in the case of a failure of any existing structure due to changes made in its function or expansion. Any structure that is subjected to a change in the magnitude and nature of loads may fail as it was not originally designed to resist such amount and type of loads. In order to prevent disasters, it is important to make changes in the load-bearing capacity of the structure so that the structure may become safe in the new conditions that it may face. It is here that the need of redesigning and retrofitting of structures comes into the picture.

1.1 Disasters A disaster is a sudden calamity that greatly disturbs the normal working of people or society that it hits. A disaster causes great loss of human lives, property, environment, and economy of the hit community. Any natural calamity does not qualify to be called a disaster. A hazard becomes a disaster only when we are not ready for the effects that any calamity might bring. If the damage caused by the disaster exceeds the ability of the community or society to cope up using its own resources, it is a disaster. In this case, the community suffers a great disturbance and may take for it a long time to become normally functioning again. The disaster can be represented as: DISASTER = (VULNERABILITY + HAZARD)/CAPACITY. It means that if the community is ready for the hazard, the loss that the disaster causes can be substantially reduced. It is this readiness, the lack of which results in the conversion of a hazard into a disaster.

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149

Types of Hazards

The hazards may be caused due to natural causes or by humans. In this view, they are categorized as natural hazards and technological or man-made hazards. Natural Hazards: The causes of these natural phenomena are the slow or quick onset of various natural processes that may have different types. For example, these processes may be geophysical in nature like landslides, earthquakes, tsunamis, or the volcanic activities. The cause may be hydrological as in avalanches and floods, climatological as in extreme temperatures or long dry spells and draughts, meteorological as in cyclones and storms, or biological as in plagues and epidemics. Man-made Hazards These hazards are caused by human interference into the nature or by the technological processes used by humans for various developmental purposes. Some examples of these types of hazards are industrial accidents like nuclear plant leakages, transport-related accidents, unplanned urbanization, global warming, or climate change. These hazards are born and act in close proximity to human population. Another example is hazards caused indirectly by human activities like mining, which may lead to landslides and earthquakes.

2 Literature Review See Table 1.

3 Retrofitting Techniques Retrofitting refers to adding of new technology or features to an old system. In this project, it refers to the retrofitting of buildings using various techniques in order to increase the strength of buildings so that they are able to bear more loads. Below are certain common techniques that are used for retrofitting.

3.1 Section Enlargement or Jacketing The most widely used technique to retrofit various structural members is Jacketing. Axial strength, stiffness, and bending strength of the original column are increased by jacketing. In this method, the members are jacketed with reinforcements, and then, concrete is poured around the already standing members [1]. This gives a member with greater reinforcement and increased area. Common process is to increase the roughness of the interface and then applying a bonding agent like epoxy resin. Steel

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Table 1 Literature review S. No.

Name of the paper

Authors

Description

1

Seismic performance of reinforced concrete columns reinforced by various methods

Gia Toai Truong, Jong Chan Kim, Kyoung-Kyu Chai

Study and development of various methods of retrofitting for concrete columns without seismic reinforcement

2

Seismic retrofitting of structures by steel bracings

G Navya, Pankaj Aggarwal

Retrofitting process on a building designed as per IS 456: 2000 and IS 1893: 2002 and use of steel bracings for retrofitting

3

Behavior of steel jacket retrofitted RC columns with preload effects

And He, Jian Cai, Qing-Jun Chen, Xinpei Liu, Jin Xu

Many concrete steel jacketed columns are tested for different loads and eccentricities

4

Experimental study of the effectiveness of retrofitting RC cylindrical columns using self-compacting concrete jackets

Rahul Dubey, Pardeep Kumar

Study of self-compacting concrete (SCC) mixes as a retrofitting material and also its use as jacket for cylindrical columns has been studies

5

Retrofitting square columns using FRP-confined crumb rubber concrete to improve confinement efficiency

Osama Youssf, Raza Hassanli, Julie E. Mills

Proposals for modification of cross-section of square columns for improving FRP confinement efficiency

6

Alternative retrofitting strategies to prevent the failure of an under-designed reinforced concrete frame

Marco Valente, Gabriele Milani

Proposal of different retrofitting techniques based on different strategies using nonlinear static analysis for preliminary estimation

7

Experimental behavior of full-scale exterior beam-column space joints retrofitted by ferro-cement layers under cyclic loading

Ibrahim G, Shaban, Osama A. Seoud

Study of behavior of beam-column space joints under cyclic loading

connectors are used very rarely as it involves specialized workmanship, time, and cost. The main aim of jacketing is as follows: • Concrete confinement is increased by transverse fiber reinforcement. It is especially increased for circular cross-sectional columns. • Shear strength is also increased by transverse fiber reinforcement. • Flexural strength is also increased by longitudinal fiber reinforcement provided.

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151

Column Jacketing

The longitudinal and transverse reinforcements are added with concrete around the existing column in this process. It not only improves the shear strength but also the axial strength of the column. Though, the strength of beam-column joints and flexural strength of column remain unchanged, and it is also not successful for improving the ductility. The improvement of lateral load capacity of the building in a distributed and uniform way is known to be its major advantage. The jacketing of columns is usually carried out by either of the methods below: (i) Reinforced concrete jacketing (ii) Steel jacketing

3.1.2

Beam Jacketing

Jacketing of beam is suggested for several purposes. It gives continuity to the columns. It also improves the stiffness and strength of the structure. The flexural resistance must be carefully computed to evade the formation of a strong beam-weak column system while jacketing a beam. In the retrofitted structures, the possibility of a change of redistribution of forces and mode of failure is very strong which a result of jacketing of columns is. It may cause the beam hinging [2].

3.2 Carbon Fiber Reinforced Plastic (CFRP) High strength fibers embedded in a matrix of polymer resin are used in CFRP. Glass, aramid, and carbon can be used in this technique. Unidirectional fibers are preferred in strengthening applications. To attach the composite surfaces to other surfaces, adhesives like acrylics, urethanes, and epoxies are used. High bond strength with high-temperature resistance is provided by epoxies, and on the other hand, moderate temperature resistance with rapid hardening and good strength is provided by acrylics. Surface is prepared very carefully by using processes like eliminating the cement paste, disk sander is used to grind the surface, dust is removed by using air blower, and for bond strength, surface curing is done [3].

3.3 Reinforced Concrete Shear Wall To provide stiffness, energy dissipation capacity, and lateral strength in mediumto high-rise building, RC shear walls are used. It is required to resist the lateral loads applied by wind and earthquakes. Various materials like concrete, steel, shape memory alloys, and fiber reinforced polymers are used. The materials to be used

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depend upon the different techniques of retrofitting. The lateral forces like vertical loads and bending moments are resisted about the walls’ major axis. Shear forces are also resisted along the length of the wall. Shear walls are the part of lateral force resisting system.

3.4 Steel Bracings The rehabilitation of nominally ductile moment resisting frame structures is done by steel bracings. Adequate strength, ductility, and stiffness required for the structure are provided by structure. Though, the special attention should be given to their connections with their existing structure [4]. In this particular case, to minimize the buckling length, the steel bracing can be anchored to the RC walls. It will also increase the strength of the bracing member as compared to the case of retrofitting the moment resisting frames. Addition of vertical steel strips is always advised at the wall edges when using diagonal bracings.

4 Problem Formulation In this project, we considered a G+4 structure that was already been designed. Then, requirement arises to increase the building vertically to G+7-storied structure. The aim was to expand the building vertically to increase the number of floors to G+7, which means that now the load of three additional stories had to be taken by the structure. The three additional floors lead to increase axial load, bending moment, and wind forces. In order to account for these additional loads, we redesigned the building as a G+7 structure which resulted in the change in dimensions of the columns and beams. In the case of columns, the cross-sectional area and area of longitudinal reinforcement of the already designed building and the new proposed design are compared. Based on the new dimensions and reinforcement details, the building can be retrofitted using various suitable methods, described above.

5 METHODOLOGY: Methodology Followed Is as Followings 5.1 DESIGN USING STAAD Was Carried Out Both for G+4 and G+7 Storied Building Figures 1, 2, and 3 show the STAAD design of existing structure, while Figs. 4, 5, and 6 show the similar details of the proposed structure.

Feasibility of Redesigning and Retrofitting of a Structure … Fig. 1 Isometric view of existing structure

Fig. 2 Section view of existing structure

5.2 Comparison of (G+4) Design with (G+7) Design Details of Existing Structure (G+4) Height of structure = 17.500 m Length of structure = 16.000 m Breadth of structure = 16.000 m Height of each floor = 3.500 m

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Fig. 3 3D rendering view of existing structure

Support condition = Fixed Size of beam = 250 mm × 300 mm Size of column = 300 mm × 300 mm Thickness of slab = 150 mm Material properties Grade of concrete = M30 Grade of steel = Fe415 Elasticity constant = 2.17 × 107 kN/m2 5.2.1 • • • • • • •

Details of Proposed Structure (G+7)

Height of structure = 28.000 m Length of structure = 16.000 m Breadth of structure = 16.000 m Height of each floor = 3.500 m Support condition = Fixed Size of beam = 250 mm × 400 mm (assumed) Size of column = 400 mm × 400 mm (assumed)

Feasibility of Redesigning and Retrofitting of a Structure … Fig. 4 3D view of proposed structure

Fig. 5 Sectional view of proposed structure

155

156 Fig. 6 3D rendering view of proposed structure

• • • • • • • • • • • • • • • • •

Thickness of slab = 150 mm Material properties Grade of concrete = M30 Isometric View of Proposed Structure Grade of steel = Fe415 Elasticity constant = 2.17 × 107 kN/m2 Dead load Unit weight of concrete = 25 kN/m3 Unit weight of masonry wall = 20 kN/m3 Dead load of slab = 3.75 kN/m2 Floor finish = 0.75 kN/m2 Load of parapet wall = 2.6 kN/m Load of inner wall = 8.06 kN/m Load of outer wall = 14.26 kN/m Live load Live load on floor = 4 kN/m2 Live load on roof = 1.5 kN/m2

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Table 2 Comparison of area of steel in columns of the existing and modified structure (ground floor) Column No.

Required steel area (mm2 ) Case 1 (existing structure)

Case 2 (proposed structure)

1

720

3 5

Increase in required steel area (mm2 )

% Increase

1280

560

77.8

720

1280

560

77.8

720

1280

560

77.8

7

720

1280

560

77.8

9

720

1280

560

77.8

15

720

1280

560

77.8

17

540.8

901.96

361.16

66.8

19

552.04

932.12

380.08

68.9

21

540.8

901.96

361.16

66.8

23

424.05

684.87

260.82

61.5

29

720

1280

560

77.8

31

552.04

932.12

380.08

68.9

33

720

1280

560

77.8

35

720

1280

560

77.8

37

427.97

705.17

277.2

64.8

43

720

1280

560

77.8

45

540.8

901.96

361.16

66.8

47

720

1280

560

77.8

49

720

1280

560

77.8

51

434.61

684.87

250.26

57.6

57

720

1280

560

77.8

59

424.05

684.87

260.82

61.5

61

427.97

705.17

277.2

64.8

63

434.61

684.87

250.26

57.6

65

371.91

516.29

144.38

38.8

6 Results and Conclusion Tables 2, 3, and 4 show the required modification in terms of area of steel (Tables 2 and 3) and area of concrete (Table 4) that is to be done in the structure in order to retrofit it (Fig. 7).

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Table 3 Comparison of number of bars used in columns of the existing and modified structure (ground floor) Columns

Reinforcement required (existing structure)

Reinforcement required (proposed structure)

Number of bars (existing structure)

Number of bars (proposed structure)

C1

720

1280

Provide 4—16 dia

Provide 12—12 dia

C2

540.8

901.96

Provide 4—16 dia

Provide 8—12 dia

C3

424.05

684.87

Provide 4—12 dia

Provide 8—12 dia

C4

427.97

705.17

Provide 4—12 dia

Provide 8—12 dia

Fig. 7 Placement of columns

7 Procedure of Column Jacketing After the structural analysis of a column is carried out, the results give us an estimate about the size of the jacket to be used, the size of the member or the diameter and number of steel bars to be used in the process of jacketing. In some cases, in order to carry out the process of jacketing, the prerequisite is that the loads on the columns be reduced or even removed completely. Figure 8 shows a jacketed column. This is carried out as shown in the steps below. • Mechanical jaws are put in place in between the floors. • Additional props are put in place in between the floors. In addition to this, if the reinforcement bars are found to be corroded, some additional steps need to be followed, which are given below: • The concrete cover from the member is removed. • The steel reinforcement bars are cleaned using sandpaper or wire brush. • In order to prevent further corrosion, the steel reinforcement bars are coated with an epoxy material. In case the above steps are not needed, the jacketing is carried out as follows:

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Table 4 Comparison of area of concrete in columns of the existing and modified structure (ground floor) Column No.

Required concrete area (mm2 ) Case 2 (proposed structure)

Increase in Required Concrete Area (mm2 )

% Increase

Case 1 (existing structure)

1

89,280

158,720

69,440

77.8

3

89,280

158,720

69,440

77.8

5

89,280

158,720

69,440

77.8

7

89,280

158,720

69,440

77.8

9

89,280

158,720

69,440

77.8

15

89,280

158,720

69,440

77.8

17

89,459.2

112,745.38

23,286.18

26.0

19

89,447.96

116,515.55

27,067.59

30.3

21

89459.2

112745.4

23286.2

26.0

23

53006.81

85608.2

32601.39

61.5

29

89280

158,720

69,440

77.8

31

89,447.96

116515.55

27067.59

30.3

33

89,280

158,720

69,440

77.8

35

89,280

158,720

69,440

77.8

37

53496.53

88146.78

34650.25

64.8

43

89,280

158,720

69,440

77.8

45

89459.2

112745.4

23286.2

26.0

47

89,280

158,720

69,440

77.8

49

89,280

158,720

69,440

77.8

51

54326.06

85608.21

31282.15

57.6

57

89,280

158,720

69,440

77.8

59

53006.81

85608.2

32601.39

61.5

61

53496.53

88146.78

34650.25

64.8

63

54326.06

85608.21

31282.15

57.6

65

46489.11

64536.38

18047.27

38.8

1. Steel connectors are added into the column so as to tighten the stirrups of the jacket that are to be added vertically as well as horizontally. In the directions, the spacing of connectors is kept not more than 50 cm. Holes are made into the column which is about 3–4 mm larger than the diameter of the connectors that are to be used. The depth of these holes is kept as 10–15 cm. 2. These holes are then filled with the right epoxy material, and steel connectors are then inserted into the holes. 3. The step 1 and 2 are again followed in order to add the vertical steel connectors so as to tighten the vertical steel bars to be used in the jacketing.

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Fig. 8 Different views of a column with jacketting

4. The stirrups and the vertical steel bars, the size and diameter of which is chosen as per the design, are added to the jacket. Thus, in this way, the additional reinforcement requirement is met. 5. In order to create a strong bond between the existing concrete and the new concrete, the old column surface is coated with suitable epoxy. 6. The concreting of the jacket should be done before the epoxy dries so as to make a good bond between old and fresh concrete layers. Also, the concrete used for jacketing should have very less shrinkage. This can be achieved by using smaller aggregates and adding suitable admixtures in order to prevent shrinkage.

8 Conclusion The design parameter of the ground floors columns is compared. It is seen that the requirement of steel and concrete increases in the proposed structure due to increased loads. Accordingly Column section also increased from 300 × 300 to 400 × 400 mm. There are different retrofitting techniques that can be employed to increase the strengthening of the structure so as to make it safe for bearing the

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increased loads due to vertical expansion of the building. Here thus, we can use column jacketing to increase the area of columns and provide the extra steel bars. After redesigning the structure, it becomes evident that the same structure can be extended by another three floors by increasing the column and beam thickness of existing structure by jacketing with increased reinforcement, without demolishing the existing structure. However, to avoid any disaster, same structure cannot be extended without retrofitting measures. NOTE: The foundation for a (G+4) structure may not be sufficient for a (G+7) structure. But in this study, the retrofitting of foundation has not been considered, and focus of calculations is on the retrofitting of columns.

References 1. Sengupta AK, Reddy CS, Narayanan B, Asokan Seismic analysis and retrofit of existing multistoried buildings in India—an overview with a case study 2. Rani A, Paul DK Seismic retrofitting of a damaged school building, 1 M.Tech Student, CoEDMM, IIT Roorkee, India, Emeritus Fellow, Department of Earthquake Engineering, IIT, Roorkee, India 3. Concrete structures repair, rehabilitation and retrofitting by Prof. (Dr.) J. Bhattacharjee, Advisor, Civil Engineering, Amity University, Noida 4. Marlapalle VC, Salunke PJ, Gore NG Analysis and design of RCC jacketing for buildings

Comparison of Number of Piles Required for Deep Foundation Design Using Indian and European Codes Modita Kulshrestha, Altaf Usmani and Rajan Srivastava

Abstract Pile work contributes as a major component of material consumption in civil engineering domain of a refinery, a petrochemical complex construction or an industrial project in general. Most of the current project sites often require use of piles as foundation due to the poor soil conditions and poorer bearing capacities. The current practice in Indian refinery sector is to design the piles and their arrangements according to the provisions of Indian standards. Indian standard adopts the “working stress design approach” which has been in extensive use till date for the design of gamut of foundations, viz. isolated footings, raft foundations, pile foundations, etc. with a global factor of safety. However, internationally a new design concept, limit state design approach as per Eurocode has gained popularity in recent times. Eurocodes are a well-established benchmark for many countries all over the world. Eurocodes lay emphasis on soil–ground interactions, besides just superstructure and explain the design of soil–ground interactions in such a way that limit states may be reached for pile groups as well. Recent designs of pile and pile group arrangement in Indian parlance using the European standards have shown encouraging signs of savings in terms of reduced number of piles required. This paper presents a comparative study of the number of piles required for a pipe rack structure in a refinery complex using Indian standard and Eurocodes. This paper further gives the quantitative idea of possible savings in materials that can be attained using the advanced code and attempts to explore the reason for the same. The possible savings in carbon footprint during refinery construction due to this material saving have also been attempted. Keywords Indian codes · European codes · Limit state · Working stress method · Pile foundation

M. Kulshrestha (B) · A. Usmani · R. Srivastava Engineers India Limited, New Delhi 110066, India e-mail: [email protected]; [email protected] © Springer Nature Singapore Pte Ltd. 2020 S. Adhikari et al. (eds.), Advances in Structural Engineering and Rehabilitation, Lecture Notes in Civil Engineering 38, https://doi.org/10.1007/978-981-13-7615-3_14

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1 Introduction The implementation of Eurocodes has been done in recent years replacing British Codes for maintaining uniformity across the European nations, and it is further aimed to implement it globally. Eurocode 7 (EC7, EN1997: Geotechnical design) is based on the limit state design concept and characteristic values. According to European Norm [1], designs to ensure that the occurrence of the limit state is sufficiently unlikely maybe carried out using either of the following methods: • The partial factor method and • Probabilistic methods A stark feature of Eurocode is that it has a wide range of factors for different situational cases on the key parameters, viz. load, material, soil parameters, and pile capacity. • Loads: Eurocode recognizes the nature of load and provides ultimate load factors for analysis and design against the load factor “unity” considered in working stress, which seems to be a more practical approach. • Pile capacity: Eurocodes has specific factors based on reliability of test results, number of tests, and minimum factors based on statistics to be used. A very pragmatic feature is that the design pile capacity is also dependent on nature of loads and their combinations. • In conventional working stress approach, ultimate capacity is being calculated from code/book empirical equations and is reduced by a global factor of safety which varies from 2.0 to 3.0. The same is verified with test results during execution. • Soil parameters: Factors for different soil parameters are clearly specified in Eurocodes on which the working stress method is silent, again a key factor in the design of any foundation. • Factor of safety for material is, however, specified in both. Eurocode 7 provides tabulated partial factors for actions (i.e., loads), material properties, and resistances. Design engineers select appropriate partial factors from the table and carry out design calculations using a trial-and-error approach. The calibration of partial factors in Eurocode 7 has been primarily based on deterministic methods that calibrate to the long experience of traditional design with the aid of historical and empirical methods [3]. The objective of the paper is to explore the possibility of implementing new and popular limit state design approach for foundation design in Indian industry, which in turn reduces the material consumption, ultimately leading to the need of the hour “Energy Efficiency.”

2 Design Approaches and Combinations Partial factors may be applied either to ground properties (X) or resistances (R) or to both as per basic design resistance equations 2.7 a, b, and c [2]. For limit state types structural (STR) and geotechnical (GEO) in persistent and transient situations,

Comparison of Number of Piles Required for Deep Foundation …

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three design approaches are outlined in clause 2.4.7.3.4 ref. EN1997-1:2004. The partial factors to be used are denoted as A (for actions or effects of actions), M (for soil parameters), and R (for resistances). Further, here A1/A2 are set of partial safety factors on actions and effects of actions, and M1/M2 are two sets of partial safety factor on soil properties. R1/R2/R3/R4 are sets of partial safety factors for resistances. For the purpose of understanding, all the design approaches are given below:

2.1 Design Approach 1 In Design Approach 1, for all designs, checks are in principle required for two sets of factors applied in two separate calculations. The combinations of sets of partial factor values that should be used for Design Approach 1 are as follows: Combination 1 abbreviated as DA1.C1 : A1 + M1 + R1

(1)

Combination 2 abbreviated as DA1.C2 : A2 + M1 or M2 + R4

(2)

where “+” implies “to be combined with”.

2.2 Design Approach 2 In Design Approach 2, factors are applied either to actions or the effects of actions and to resistances. It shall be verified that a limit state of rupture or excessive deformation will not occur with the following combination of sets of partial factors; Design Approach 2 abbreviated as DA2 : A1 + M1 + R2

(3)

2.3 Design Approach 3 In Design Approach 3, factors are applied to actions or the effects of actions from the structure and to ground strength (material) parameters. It shall be verified that a limit state of rupture or excessive deformation will not occur with the following combination of sets of partial factors: Design Approach 3 combination1 abbreviated as   DA3.C1 : A1∗ or A2t  + M2  + R3(EQ NO.)

(4)

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where “*” partial action factor set A1 is applied to structural actions and “t” partial factor set A2 is applied to geotechnical actions. Since all the R3 values are unity, DA3 should not be used for piles designed from pile load tests or from resistances calculated from profiles of test results as it provides no safety on the resistance. Design Approach 1 is suggested in UK national Annexure. For the purpose of this paper, the case study is done based on structural and geotechnical actions based on Design Approach 1. Refer Annexure A of EN1997-1:2004 for various partial and co-relation factors for ultimate limit states and recommended values.

3 Case Study 3.1 Site Description The site chosen is in the heart of the great African subcontinent. The geology of the project site is of the sedimentary formation of the Quaternary era. The site sits astride the coastal plain sands formation. The age of the formations ranges from Pliocene to recent. It falls within the coastal shores of the Atlantic with alluvial subsoils which comprise mainly of sands and clays or mixture of both at varying degree or percentages of composition. The formation of the coastal plain sand formations are soft, very poorly sorted clayey sand/sandy clays which are pinkish red and brownish in color. The average groundwater table (GWT) was encountered at about 0.10–5.0 m below existing ground level. The SPT values for the soil type range from 2 to 86 for 75.0 MT piles of 25.0 m length and 500 mm diameter.

3.2 Pile Design Capacity and Ultimate Capacities The pile considered in this study is “driven cast in situ” pile with a diameter of 500 mm and length of 25.0 m, and pile cutoff level is at 1.5 m below finished grade level. Pile ultimate compressive resistance is the sum of ultimate base resistance and ultimate shaft resistance, and pile ultimate uplift resistance is 0.67 times ultimate shaft resistance. Pile capacities in axial compression, shear, and uplift are given in Table 1.

3.3 Load Combinations as Per Eurocodes Eurocode mandates provision for limit state design for foundation system. However, to cater the uncertainties, it introduces a model factor to be applied to find the design

Comparison of Number of Piles Required for Deep Foundation … Table 1 Pile design and ultimate capacities

Type of pile

Capacities of pile (in MT) Axial compression (MT)

Type-II (driven cast in situ) Ultimate capacity

167

Horizontal shear (MT)

Uplift (MT)

75

8

46

188

20

115

Table 2 Load combinations as per Design Approach 1 for ULS for 75 MT Permanent load

Variable load

Permissible design ultimate capacity (in MT, covering wind, and seismic) Compression

Tension

Shear

CASE I

1.35 or 1

1.5

188/(1.2 × 1.0) = 156.00

115/(1.2 × 1.25) = 76.00

20/(1.2 × 1.0) = 16.00

CASE II

1 or 0.9

1.3

188/(1.2 × 1.3) = 120.00

115/(1.2 × 1.6) = 60.00

20/(1.2 × 1.3) = 12.00

ultimate capacities if the ultimate capacity of piles is obtained from SPT values and soil properties. UK National Annexure of Eurocode suggests model factor of 1.2 (it may vary depending on the level of uncertainty) to be considered in design if post verification to be done by pile load testing. Eurocode has introduced correlation factors for assessing design ultimate capacities depending on type of tests conducted for pile and ground interaction in a number of tables (Refer Tables A.9, A.10, A.11 EN19971:Eurocode7). Out of three design approaches, UK National Annexure of Eurocode suggests Design Approach1 to be adopted for load combinations for foundation design and gives partial resistance factors (R1 and R4) corresponding to these load combinations. Eurocode suggests two combinations in Design Approach1, namely Design Approach1 combination and Design Approach1 combination2 usually abbreviated as DA1CI and DA1C2 as already discussed. The factors to be considered for load combination as per Design Approach 1 are as per Table 2 for 75 MT designated pile: Now that we have arrived at the pile capacities for the two cases as per Design Approach 1, let us take an example and compare the number of piles required.

4 Design Example Five-tier pipe rack is approximately 30.0 m high, 24 m wide, and 600 m long (Fig. 1). It supports some heavy air coolers on the top tier, electrical and instrumentation trays at second tier, and a number of small bore and large bore utility and process lines on

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Fig. 1 Typical pipe rack cross-sectional view. Source EIL Report

other tiers. It has five tiers, four with an approx. loading of 350 kg/cm2 and one tier with a load of 2000 kg/m2 . The bottom of foundation for design purpose is assumed at 2.0 m below finished grade level, and the foundation is assumed to be rectangular in shape. A typical cross section of the same is shown (Fig. 1): Working stress load factor, for gravity loads, is 1.0/0.9 and for lateral loads, 1.0, respectively. However, Eurocode load factors for permanent and variable actions for Design Approach 1 comb. 1 and Design Approach 1 comb. 2 are 1.35/1.5 and 1.0/1.3, respectively. • In working stress for gravity loads, no increase in pile capacity is recommended; however, for lateral loads a general practice of increasing the same by 25% is being followed by most designers. • As per Eurocodes, various factors for our DA1C1 and DA1C2 are suggested. A comparison of pile capacities at working loads as per conventional approach in Indian scenario and that at ultimate loads as per Eurocodes is depicted below in Table 3. The structure was analyzed for various sets of load combinations of dead, operating, hydrotest, wind, and seismic loads for working stress, viz. De+WL, Do+WL, Dh+0.25WL, De+SL, Do+SL, Dh+0.25SL. A similar analysis was also done

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Table 3 Permissible pile capacities Permissible pile capacities at working loads

Permissible pile capacities at ultimate loads

Load/comb.

Load/comb.

Comp.

Tension Shear

MT

Comp.

Tension Shear

MT

Gravity load

75

15

8

A1 “+” M1 “+” R1

156

76

16

Gravity + WL/SL

93.75

18.75

10

A2 “+” M1 or M2 “+” R4

120

60

12

for Eurocodes DA1C1 load combinations, viz. 1.35De+1.5WL, 1.5Do+1.35WL, 1.35Dh+0.375WL, 1.35 De+1.5SL, 1.35Do+1.5SL, 1.35Dh+0.375SL and that for DA1C2 load combinations, viz. 1.0De+1.3WL, 1.0Do+1.3WL, 1.0Dh+0.325WL, 1.0De+1.3 SL, 1.0Do+1.3 SL, 1.0Dh+0.325 SL. (where De stands for erection load, Do—operating load, Dh—hydrotest load, WL—wind load, SL—seismic load). The above analyses gave the following surprising results for same structure and same loading: No. of piles required for Indian working stress approach = 1260 No. of piles required as per Eurocode Design Approach 1 = 960 % Reduction = 23.4% A number of other, viz. heavy and tall technological structures, heavy equipment foundations, buildings, etc. too were analyzed, and a stark decrease in the number of piles required by Eurocodes, not in any particular fashion, was observed.

5 Carbon Footprint In terms of design optimization, it was observed that RCC quantity for a single pile with formerly mentioned dimensions is approximately 4.9 cum. RCC quantity of total piles as per working stress method is around 6185 cum against an RCC quantity of 4715 cum as per Eurocodes. This clearly shows a voluminous saving of 1470 cum in terms of carbon footprint, even if we ignore the savings of steel reinforcement.

6 Conclusion Study conducted in this paper shows that under the same loading conditions, a significant reduction in number of piles is achieved when EC7 is used in comparison with traditional working stress method adopted widely in Indian subcontinent. The prime reason for the same is the introduction and use of partial safety factors prescribed in EC7 on load, material, soil parameters, and pile capacity which are intended to

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simulate actual and a more practical design condition. Thus, based on the result revealed in this study, it is observed that EC7 is one of the most economical codes for analysis and design of pile foundations. The core in EC7 is that design load must be less than or equal to the corresponding design resistance, which provides no measure of the degree of overdesign, and 1.01 factor of safety is accepted and considered safe in design. However, some apprehensions are raised on this safety factor by many clients. Therefore, it is recommended that some amendments must be made to restrict minimum safety factors. Acknowledgements Authors are thankful to the EIL Management for allowing us to publish this paper and to the entire structural department of EIL for their guidance and support at every step, making this study possible.

References BS EN (1990:2002) Eurocode—basis of structural design, London, British Standards Institution EN (1997-1:2004) Eurocode 7—geotechnical design, part I: general rules, Brussels: European Committee for Standardisation Orr TL, Breysse D (2008) Eurocode 7 and reliability-based design. In: Phoon (ed) Reliability-based design in geotechnical engineering: computations and applications (Chapter 8), pp 298–343, Taylor & Francis

Comparative Analysis of Cement Mortar Roof Tiles Using Agricultural Waste Prakhar Duggal, Bishwajeet Yadav, Harsh Choudhry and Arpit Garg

Abstract In our research, we worked over the effects of using RHA and sugarcane baggage ash as a partial weight of cement replacement in cement mortar roof tile production. This work is based on an experimental study of roof tiles produced with ordinary Portland cement (OPC) and 10, 15, 20% (OPC) replaced by RHA and with sugarcane baggage ash separately. Rice husk and sugarcane baggage were brought form Bulandshahr and Allahabad and ash was produced by open-air burning the rice husk and sugarcane baggage away from the city. The tests which were performed evaluate the performance of this material were compressive strength, wet transverse strength, and water absorption. The samples were produced according IS CODE 1237-2012. Overall results show that RHA and sugarcane baggage ash have a reasonable potential to be used for the production of cement mortar roof tiles. Utilization of these waste materials will benefit society economically as well as environmentally. Keywords Ordinary Portland cement (grade 43) · Rice husk ash (RHA) · Sugarcane baggage ash · Wet transverse strength · Water absorption · Compressive strength · Stone dust

P. Duggal (B) · B. Yadav · H. Choudhry · A. Garg Department of Civil Engineering, Amity University, Noida, Uttar Pradesh, India e-mail: [email protected] B. Yadav e-mail: [email protected] H. Choudhry e-mail: [email protected] A. Garg e-mail: [email protected] © Springer Nature Singapore Pte Ltd. 2020 S. Adhikari et al. (eds.), Advances in Structural Engineering and Rehabilitation, Lecture Notes in Civil Engineering 38, https://doi.org/10.1007/978-981-13-7615-3_15

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1 Introduction As we can see, construction industry is growing at a very fast pace and has grown in many folds in the last few decades with lots and lots of powerful and applicable building equipment and methodology. Rising consumption of cement is also contributing to the global warming. Also the current scenario is that, everyone seeking for an affordable and comfortable house to live in, every scientist and engineer is working hard to develop and use new building materials that would be durable and also cost effective as well. Building materials range from roofing sheet, concrete, gravels, sand, cement, roofing tiles, etc. [1] Cement, as we all know, is the major traditional binder in the construction industry is very expensive. This is due to urbanization and phenomenal population growth which has led to ever-increasing demand of cement for various construction purposes to fulfill the needs. Researches show that the cement industry is responsible for contributing a major amount of carbon dioxide (CO2 ) emission in the atmosphere which approximately adds up to 7% of the whole world. Therefore due to the high void between the requirements and higher cost, it has led to investigate the use of cheaper alternative sources [2]. A look around the environment reveals huge production of agricultural waste, some of which can be converted as a useful construction material which would act as an alternative sources but less expensive cement mortar roof tiles which could be within the reach of the poor people also. [3] The current work aims at determining physical properties of materials, i.e., RHA, sugarcane baggage ash when used with stone dust, individually and in a mix. The separate roof tile specimens are made by replacing cement with RHA and sugarcane baggage with variation at 10, 15, and 20% and comparing the varied samples for physical properties, viz. compression test, water absorption test, and wet transverse strength to conventional roof tile in accordance with IS 1237-2012.

2 Methodology In our research, we used ordinary Portland cement of grade 43, stone dust, water RHA, and sugarcane husk ash freshly prepared by open-air burning. Special molds were made for the preparation of making the tiles the dimension for the tiles being prepared are 280 mm × 150mm × 10mm. Before using it for casting process, they were cleaned with a clean cloth and then they were lubricated using oil and grease with a brush. After proper lubrication process, the molds were taken and assembled and after that screws were tightened. Different batches for tiles having different mix designs were skilfully calculated and formulated to check for the best possible combination of the above-mentioned materials 10, 15, 20%.

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2.1 Mixing Design The materials consisting of the concrete mixture were firstly, weighed on the weighing scale and then they were inserted inside the mechanical mixer manually. Around ten specimens of tiles and cubes were produced in a single batch. After that, water was added to the mixture gradually while the mixer was rotating. The following mix design is used for preparation of specimen: Water–Cement ratio = 0.4 Cement-Stone Dust ratio = 1:2 Controlled Cement mortar for one tile Composition:

Cement (g)

Sand (g)

Water (g)

463

779

231.5

According to the normal mixing ratio mentioned above, the ratio should be: We will replace cement with RHA and sugarcane husk ash first at 10% then the mix will be prepared for 15% replacement then 20% replacement. All the experiments conducted are according to the IS CODE 1237-2012 and performed under the presence of our guiding faculty. In total 80 sample tiles, 80 cubes were prepared after casting for various mix designs mentioned above each of the replaced cement ratios including the conventional samples.

3 Experimental Work and Results Due to preciseness requirement and also due to the less time availability for this research, replacement level was limited to up to 20% replacement of cement. Cube samples of size 70.6 × 70.6 mm for 7, 14, and 28 days were tested for compressive strength. In the present experiment, cubes and tile specimens were cured in water to attain 28-day strength and the curing process was performed using the steam curing machine which was available at our Material Testing Laboratory. Tiles of size 280 × 150 × 10 mm for 28 days were tested for wet transverse strength and water absorption according to IS CODE 1237-2012. Test on specimens with varying percentage of cement with RHA and sugarcane baggage ash are performed. A total of 90 tiles and 90 cubes samples were produced for various tests which were carried out during this research work. The results for compressive strength and wet transverse strength are shown (Graphs 1 and 2) Result for Wet Transverse Strength Test: See (Tables 1 and 2).

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Graph 1 Compressive strength for sugarcane baggage ash

Graph 2 Compressive strength for rice husk ash

Table 1 Result for sugarcane baggage ash mixture S. No.

Composition

Specimen Age day

Size of specimen (mm2 )

Wet transverse Strength (Avg.) N/mm2

1

Conventional (0% replacement of cement)

28

42000

9.1

2

10% Sugarcane baggage ash

28

42000

5.7

3

15% Sugarcane baggage ash

28

42000

6.4

4

20% Sugarcane baggage ash

28

42000

7.1

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Table 2 Result for RHA mixture S. No.

Composition

Specimen Age day

Size of specimen (mm2 )

Wet transverse Strength (Avg.) N/mm2

1

Conventional (0% replacement of cement)

28

42000

9.1

2

10% RHA

28

42000

7.2

3

15% Rice husk ash

28

42000

6.4

4

20% RHA

28

42000

5.5

(According to IS Code-1237-2012) Table 3 Result for RHA mixture S. No.

Composition

7th Day

14th Day

28th Day

1

Conventional (0% replacement of cement)

3.2

3

1.9

2

10% RHA

4.4

3.6

2.1

3

15% Rice husk ash

4.9

3.8

2.7

4

20% RHA

3.6

3.5

2.9

Table 4 Result for sugarcane baggage ash mixture S. No.

Composition

7th Day

14th Day

28th Day

1

Conventional (0% replacement of cement)

3.2

3

1.9

2

10% Sugarcane baggage ash

4.9

4.2

3.1

3

15% Sugarcane baggage ash

4.4

3.9

2.1

4

20% Sugarcane baggage ash

3.9

3.3

2.7

Result for Water Absorption Test See (Tables 3 and 4).

4 Conclusion The intent of this project has been fulfilled with significant improvement of cement mortar paste properties with, addition of RHA and sugarcane baggage ash in mortar mix. It increases workability as far as the w/c ratio is balanced to meet the standard consistency of cement paste. RHA blended concrete improves the compressive strength as well as wet transverse strength. It works in the same way for sugarcane baggage ash. It increases the workability and w/c ratio for the cement mortar mixture. It is observed during the testing process, the compressive strength of the specimens is maximum at 10% replacement of cement with RHA which came to be 33.4 N/mm2

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and after that, it was observed that the strength decreases whereas for replacement of cement with sugarcane baggage ash it is maximum at 15% which came to be 30.0 N/mm2 . Inclusion of RHA beyond 10% leads to decrease in wet transverse strength of the tiles where as it is observed that wet transverse strength increasing in sugarcane baggage ash beyond. The entire observed outcomes match the level of minimum requirement value, i.e., 3 N/mm2 in IS CODE 1237-2012.

References 1. IS 3978-1967 Indian standard code of practice for manufacture of burnt clay Mangalore pattern roofing tiles 2. ASTM C33/ C33 M-13 (2013) Standard specification for concrete aggregates, ASTM International, West Conshohocken, PA, 2013. www.astm.org 3. Nnamdi OP (2011) Low cost materials for buildings and construction: a case study of rice husk. J Sustain Dev Environ Pollut, 2011

Use of Waste Plastic in Wearing Course of Flexible Pavement Prakhar Duggal, Avneesh Singh Shisodia, Suparna Havelia and Keshav Jolly

Abstract This paper brings to light the use of waste plastic in the construction of roads. The waste plastic generation is increasing significantly on a daily basis. Through this review, we intend to find the efficient and feasible ways to reutilize the waste particles in hard-plastic waste as a bitumen modifier primarily for flexible pavements like bitumen and bituminous concrete roads. The use of waste plastic in recycled form in the pavement asphalt can serve as a valuable outlet for such type of waste materials. By using the concrete having modified bitumen mix along with processed waste plastic of about 5–10% by wt. of bitumen leads to a substantial improvement in the fatigue life, strength and other properties desirable in bituminous concrete. Consequently, it improves the service life and pavement performance with a marginal but significant saving in usage of bitumen in road construction. This process is certainly environment-friendly. Using waste plastics in the construction of pavements helps to consume large quantity of plastics which are hazardous waste. Thus, these processes also have high social and ecological relevance and contribute toward sustainable development. There are two processes to mix the plastic in surface layer of the road wet process and dry process. We are using wet mix process for the bitumen mix design by adding plastic waste and compare the results with the standard bitumen mix. We have chosen Marshall mix design for the calculation of grading and optimum bitumen and plastic content in mix. We are mainly focusing on surface layer of wearing course of about 50 mm thick, i.e., surface layer of road. This could be helpful in managing waste plastic while improving road quality and making them economical too. Keywords Marshall mix design · Bitumen concrete · Hard plastic · Flexible pavement

P. Duggal (B) · A. S. Shisodia · S. Havelia · K. Jolly Department of Civil Engineering, Amity University, Noida, Uttar Pradesh, India e-mail: [email protected] © Springer Nature Singapore Pte Ltd. 2020 S. Adhikari et al. (eds.), Advances in Structural Engineering and Rehabilitation, Lecture Notes in Civil Engineering 38, https://doi.org/10.1007/978-981-13-7615-3_16

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1 Introduction Waste plastic has threatening consequences on our environment, which makes its management and disposal a major concern. Our project is based on addition of plastic into road construction, with emphasis on adding plastic into surface layer of the road so that it could partially replace bitumen and aggregate into bitumen concrete, thus making it more durable and water resistant up to some extent. This could lead to more economical roads of better quality. However, a large quantity of plastic can be used as a landfill, but for now during this project, we are not focusing on that part. There are certain properties of plastic which are similar to that of bitumen such as melting point, setting time and ductility; they both can be used as a binder, etc. The road is laid at a temperature of 160 °C, and the plastic is also in molten format this range of temperature, making it comparatively easier to mix with bitumen. The water repellent property of plastic can also be utilized to make more durable road in regions receiving higher annual average rainfall. The non-biodegradable nature of plastic could contribute to increased road life. Recent research papers on similar topic have found a noticeable increase in road’s strength, water resistance and overall life span after introducing plastic into the bitumen concrete mix. Also, an increase in melting points can prevent bleeding of bitumen. In road construction, there are basically two methods which can be adopted to add plastic in bitumen concrete: 1. Wet mix method 2. Dry mix method Till now, only 8% of partial replacement of bitumen has been achieved via wet mix process, and 15% partial replacement of aggregates have been observed via dry mix process. In dry mix method, plastic is melted and added to the molten bitumen at a certain controlled temperature. This mixture is used to prepare bitumen concrete along with the aggregates. Till now, researchers have been able to add 7.5% plastic to the mix by using this method. This method reduces the amount of aggregate to be used in mix hence making it more economical. In wet mix process, there is another way by which plastic can be added into mix. We can add shredded plastic to our bitumen. Past recent studies have been done mostly on dry mix process. So, we have carried out our project on wet mix process; in this project, we have compared results of wet mix process, i.e., addition of shredded plastic to bitumen with the conventional bitumen concrete. Plastic is basically of two types: thermoplastic and thermosetting plastic. Thermoplastics, which constitute of about 80% of the plastics, are the ones which can be molded again when heated to a certain temperature and thus recyclable. However, their quality degrades after every time they are recycled. The subtypes of thermoplastic are polyethylene, polypropylene, polythermide, polyketone, Teflon, LDPE

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(low-density polyethylene), etc. But at B.Tech. level, we are unable to differentiate between the forms of plastic, so we are using most of the plastics we are getting in our day-to-day use. On the other hand, thermosetting plastics on heating at certain temperature get permanently deformed and cannot be molded again. Due to this reason, we are not using thermosetting plastic. Daily life example includes Bakelite, melamine formaldehyde (switch covers, furniture, table coverings, etc.) and urea formaldehyde (switch covers, handles of utensils, fire control knobs, etc.). Bitumen is a very important component in construction of flexible pavements and is also known as asphalt in countries like America, etc.; bitumen is a by-product which is obtained during the distillation of crude oil and possesses favorable properties so that it can be used in road construction such as having a melting point of around 110–120 °C which is favorable for the working condition as no new equipment is required to heat it. Bitumen is nontoxic and has high molecular density, so it acts as a strong adhesive; hence, it can bind the aggregate all together even in loading conditions of vehicles. We have used the bitumen of viscous grade VG30. We are opting Marshall mix design method for design of wearing course of flexible pavement. This test helps us to determine the optimum bitumen and plastic content that can be mixed. We aim for designing the thickness of 50 mm road surface. Accordingly, we have considered the aggregate size and bitumen grade in medium hot climate type (VG-30). The optimum content of bitumen considered is 5.4% by wt. of the sample. Therefore, since sample weight was 1255 g, then weight of bitumen taken is 69 g. Plastic content used is 7 g (i.e.,10% of bitumen by weight).

2 Literature Review During the commencement period of the project, we have read numerous research papers similar to our project title. Researches on the application of plastic along with bitumen have provided us useful data and procedures. Thermal behavior of bitumen is quite suitable for working with bitumen; when plastic heated at 165 °C, there is no evolution of toxic gases. When heated above 270 °C, they start to decompose and around 750 °C they get burnt and evolve harmful gases. Zoorob and Suparma [1] found out that recycle plastic is generally of low-density polyethylene, and their use has increased the durability and fatigue life of flexible pavement. And researchers Apurv and Chavan [2] found out polymer bitumen bland helps in better binding of plastic coated aggregate and bitumen. Gawande et al. [3] found out the effective ways to reutilize the hard plastic into road construction; where plastic is used as a bitumen modifier, the plastic content

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can be increased 5–10% by weight of bitumen. Fatigue life and abrasion value are found to be increased due to introduction of modified bitumen. Kulkarni [4]. The optimum quantity of the waste plastic is 10% in most of the investigations. Investigation indicates that PVC up to 10% can be used for bitumen pavement in warm regions so that bleeding can be cured. Plastic bottles, cups, mugs, etc. can be reused by powdering and blending.

3 Project Design and Implementation 3.1 Material Used Aggregates Aggregates are inert materials which provide the main constituent for construction for the road. They are naturally occurring stones which have very low reactivity and are bound with the help of bitumen. They are also artificially prepared by breaking larger rocks into small pieces. We have used different size of aggregates in varying proportions according to grading required for the design of wearing course of flexible pavement. Bitumen Bitumen is a by-product obtained during the distillation of crude oil and can also be prepared artificially by chemical processes. They are composed of complex hydrocarbons and have very dense structure. They have melting point between 80 and 120 °C. Bitumen is used as a binding agent who binds the aggregates together to form a surface. Bitumen has characteristic like ductility, low-melting point and binding ability so that it can be easily used for road construction. It also contains water repellent property. Bitumen is found in different penetration grades like grade 30/40, grade 60/70 and grade 80/100. The another way of classifying bitumen is based on viscosity paramter. We are using VG30 bitumen grade for our major project experiment condition. Plastic Plastic is a 100% man-made material which is composed of hydrocarbons. It is very easily found and is cheap economically. Over the period of time, it has become a threat to our environment due to its non-biodegradable property. But some of the plastic can be recycled and used again and again. There are certain properties of plastic which are similar to that of bitumen such as melting point, setting time and ductility; they both can be used as a binder and some other properties. Plastic is also water repellent in nature, so this property of plastic can be used to make road more durable.

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3.2 There are Two Processes to Introduce Plastic Waste into the Bitumen Mix Dry mix process (1) (2) (3) (4) (5)

Aggregates are preheated at 170 °C and bitumen at 160 °C. Aggregates are coated with plastic which improves their quality. No evolution of toxic gases. Use of waste plastic more than 15%. Increase properties like porosity, moisture, absorption and soundness.

Wet mix process (1) Plastic waste is powdered first and then melted after that it is added to bitumen mix. (2) Only 6–8% plastic is added to bitumen. (3) Shredded plastic waste acts as a binding agent. (4) There is increase of about 2–3 times in value of Marshall stability value as compared to ordinary bitumen. We are using wet mix process for the bitumen mix design by adding plastic waste and compare the results with the standard bitumen mix.

4 Experimentation 4.1 Tests on Aggregates • • • • •

Flakiness and elongation test Water absorption test Impact value test Abrasion value test Marshall stability test

Flakiness and Elongation Test Flakiness refers to the thickness of the aggregates to be used and is measured by flakiness gauge. If the aggregate has a thickness than 0.6 m, it is considered to be flaky. Elongation index can be defined as the percentage by wt. of particles whose greater dimension is 1.8 times its mean size and is measured by elongation gauge. Water Absorption Test This test determines the water absorption of coarse aggregates. For this experiment, a test sample of 2000 g or more is a must. The test sample should be free from dust and suspended particles. The sample is also immersed in distilled water for 24 h to remove entrapped air. Thereafter, it is heated to a temp. of 100–110 °C.

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Abrasion Value Test This test indicates toughness and abrasion characteristics of the aggregates. The testing apparatus is as per IS 2386 (Part IV). After testing the sample, the entire material is passed through 1.70 mm sieve and the observations are recorded.

4.2 Tests on Bitumen • Ductility test • Softening point test • Penetration test Ductility Test The ductility test is used to ascertain the extent of ductility of the mixture of bitumen and aggregate with desired quantity of plastic. The test apparatus and procedure are as per IS 1208-1978, consisting of brass briquette mold, testing machine and thermometer. Softening Point Test The softening point test of bitumen determines the softening point of the bitumen plastic aggregate. The softening point is the temp. at which the bitumen attains a certain degree of softness under pre-specified test conditions. As per IS 1205-1978, the apparatus for the softening test is the ring and ball apparatus and thermometer. Penetration Test The penetration test can be used to design grades of bitumen plastic aggregates and to measure changes in hardness. The standardized procedure for this test can be found on ASTM. A softer bitumen mixture will have a higher penetration while the harder will have the vice versa as understandable. Marshall Mix Design Marshall mix design is a design method which helps us to determine the optimum bitumen and plastic content that can be mixed in a wearing course of road. • We aim for designing the thickness of 50 mm road surface. • Accordingly, we have considered the aggregate size and bitumen grade in medium hot climate type (VG-30). • The optimum content of bitumen considered is 5.4% by wt. of the sample. So, since sample weight was 1255 g, then weight of bitumen taken is 69 g. • Plastic content used is 7 g (i.e.,10% of bitumen by weight).

Use of Waste Plastic in Wearing Course of Flexible Pavement Table 1 Observations for flakiness and elongation indices

Properties

Observations

Specific gravity

2.62

Flakiness index

15.7%

Elongation index

18.08%

Combined index

29.84%

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MORTH specifications MAX 30% (combined)

4.3 Laboratory Testing of Aggregates For construction of asphalt pavement, we make use of stone aggregate with specific characteristics. The selection of these aggregates is based on their crushing strength, porosity, moisture and absorption capacity. The waste plastic in shredded form is added to the bitumen, and together they are melted and subsequently added to the graded aggregates and then mixed. The increment in the percentage of the plastic improves the properties of these aggregates (Table 1). Following are the tests conducted in the laboratories: Impact Test (IS: 2386 Part IV-1963) Toughness can be defined as that property of a material by virtue of which it resists impact force. Road aggregates thus should possess sufficient toughness in order to resist fracture and rupture under impact force. Due to the repeated motion of vehicles, having iron-wheeled or rubber tires significant wear and tear is produced over the surface of the pavement. Hence, the impact test is designed to evaluate the impact resisting capacity of stone aggregate. The impact test was conducted with various percentage of waste plastic in aggregates in accordance with IS: 2386 Part IV 1963. The impact value thus obtained is 8.7%. Los Angeles Test (IS: 2386 Part IV) Because of the repeated movement of the rubber tyres of vehicles, there is considerable abrasion as well as wear and tear of the pavement surface. This percentage of abrasion of an aggregate sample is determined with the help of “Los Angeles Abrasion Value Test.” The results of L. A. Abrasion Value Test with various percentages of waste plastic so obtained are 15.7%. Flakiness and Elongation Test (IS: 2386 Part-I) This test indicates about the particle shape of the aggregate sample and can be ascertained by the percentage of “flaky” and “elongated” particles in the sample. Aggregate sample having high percentage of flaky or elongated particles (i.e., high flakiness and elongation indices) is detrimental to higher degree of workability and the stability of mixes.

184 Table 2 Observations for tests on bitumen for softening point

P. Duggal et al.

% of bitumen

% of plastic

Softening point

100

0

50

95

5

52

90

10

60

85

15

62

Fig. 1 Variations in softening Point of Bitumen with Increase in percentage of plastic

4.4 Laboratory Tests on Bitumen The studies were conducted on the behavior and binding properties enhanced for the preparation of blend of plastic waste-bitumen in order to find the suitability of material properties for construction of roads. Polythene bags used to carry articles were cut into small pieces by using a cutter. These waste plastic pieces were then slowly added to the hot bitumen, and using a mechanical stirrer, the mixture was stirred well. Different mixtures of the polymer bitumen and polymer aggregate were prepared by varying the compositions and used for carrying out various tests. Following are the test conducted in laboratories: Softening Point Test The softening point can be defined as the temperature of bituminous substance at which it attains softness of a certain degree under pre-specified condition of the test. A higher value of softening point is generally preferred in a warm climate, while a lower value of the softening point will be preferred in colder climate. As per IRC recommendations, the softening point of bitumen is taken as 500 °C (Table 2 and Fig. 1). Penetration Test (IS: 1203-1978) In order to ascertain the degree softness or hardness of the bitumen to be used in construction of pavements, the penetration test is conducted. It is performed through measurement of the distance to which a standard needle may penetrate a given bitumen sample. Samples having varying % of waste plastic in bitumen are pre-

Use of Waste Plastic in Wearing Course of Flexible Pavement Table 3 Marshall stability test readings

185

Sample

Concrete stability

Flow value

1

1513

3.9

2

1465

3.30

3

1517

3.40

Fig. 2 Variations in penetration value of Bitumen with increase in percentage of plastic

pared, and then their penetration values are ascertained as per relevant BIS codes. The so-obtained resultant penetration test values of the blends are evidently declining as per the % of plastic added. As per the recommendations from IRC, the penetration test values of bitumen vary between 2.0 and 22.50 cm. Ductility Test (IS 1208-1978) This test is performed in order to ascertain the ductility of bituminous substances. The basic principle of this test is that the ductility value of a bituminous substance is measured by distance in centimeters to which it may elongate before breaking. Marshall Stability Test This test has provided us the values of flow and the load that can be applied over the core samples prepared (Table 3, Figs. 2 and 3).

5 Conclusion The generation of waste plastics is expanding at a surprisingly fast pace. This survey has proposed to locate and identify the influential approaches which assist in reutilizing the waste particles in hard plastic as bitumen modifier for flexible asphaltic pavements. By utilization of altered bitumen mix concrete along with the expansion of processed waste plastic of around 5–10% by wt. of bitumen, the fatigue life, quality and other properties of solid bituminous blend, which ultimately enhances the life span and performance of the flexible pavement with minor reduction in the amount of bitumen use. The process is certainly eco-friendly. The usage of waste plastics

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Fig. 3 Variation in ductility of Bitumen with increase in percentage of plastic

in the road-making undoubtedly helps to consume substantial quantities of plastic waste. Hence, these procedures possess social, economic and ecological relevance. • It has been shown that with an increase of waste plastic in bitumen expands the properties of bitumen and aggregates. • In comparison with conventional flexible pavements, using waste plastic in flexible pavements has shown promising results. • The optimum usage of plastic can be taken up to 10%, based on the results test performed. • Reutilization of plastic waste sustainably in the pavements is an extremely environment-friendly construction technique. • Layering of plastic polymer on the aggregate’s surface leads to several benefits which in turn, facilitate improvization the quality of the pavement. • Plastic roads would definitely prove to be a boon for India’s tropical climate, where temperature surpassing 40 °C frequently across several parts of the country. • It saves approximate Rs. 45,000 per kilometer in constructing a pavement surface of road. In the dry process, the aggregate is partially modified/altered through layering with plastic polymers and producing a new and improvized building material for construction of flexible pavement. Layering of plastics over the aggregates causes significant improvement in the aggregate’s quality thus leading to an improvement in the overall pavement’s quality. This process helps to dispose 80% of the waste polymers, which is used by an eco-friendly method. In a nutshell, the dry process thus helps in • Use of a considerable amount of plastic waste. • Reduction in the requirement of bitumen by approx. 10%. • Improvement in the strength and enhancing the road performance.

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• Avoid anti-stripping agents use. • Reduction in the cost of pavement construction around Rs. 30,000 per km of single lane road at present. • Prevention of disposal of plastic waste through incineration and landfilling which has vast environmental consequences. • Develop an eco-friendly innovative technology.

References 1. Zoorob SE, Suparma LB (2000) Laboratory design and investigation of the properties of continuously graded asphaltic concrete containing recycled plastics aggregate replacement (Plastisphalt). Cement Concr Compos 22(4):233–242 2. Chavan MAJ (2013) Use of plastic waste in flexible pavements. Int J Appl Innov Eng Mgmt 2(4):540–552 3. Gawande A, Zamare G, Renge VC, Tayde S, Bharsakale G (2012) An overview on waste plastic utilization in asphalting of roads. J Eng Res Stud 3(2):01–05 4. Kulkarni SJ (2017) Use of plastic in road construction material: towards solid waste minimization. Int J Recent Trends Eng Res 03(01)

Influence of Silpozz on the Properties of Self-Compacting Recycled Aggregate Concrete M. Mishra

and K. C. Panda

Abstract This paper focuses on an experimental investigational work of raw (fresh) properties and hardened properties (HP) of self-compacting concrete (SCC) containing recycled coarse aggregate (RCA) and silpozz. In SCC mix, natural coarse aggregate (NCA) has been replaced with RCA by 0, 10 and 20%, also the cement has been replaced with silpozz by 10% of its weight. To know the raw properties of SCC, the slump cone, T500 , J-ring, V-funnel, L-box and U-box tests are carried out, whereas for HP of SCC, the compressive strength (CS) test, flexural strength (FS) test and split tensile strength (STS) tests are carried out. The M30 grade concrete is designed for this investigational work. The fine aggregate (FA) quantity increases to 35% and coarse aggregate (CA) quantity decreases to 35% with water–cement ratio (w/c) 0.43 and superplasticizer (SP) of 0.35 and 0.5%. An attempt has been taken to identify the potential use of RCA with silpozz and necessity of the raw and hardened properties for the design SCC mix. Keywords Natural coarse aggregate (NCA) · Recycled coarse aggregate (RCA) · Silpozz · Superplasticizer (SP) · Self-compacting concrete (SCC) · Workability

1 Introduction Nowadays, so many projects are going on for advanced design of construction. For that, the old existing structures are demolished and on that place, the new structures are construct. This leads to the increasing quantity of constructional waste. The waste is used as backfilling, which will create a problem or becoming problem of dispose. The earth gets polluted due to this waste. One of the best methods to eliminate M. Mishra (B) GITA Bhubaneswar, BPUT University, Bhubaneswar 752054, Odisha, India e-mail: [email protected] K. C. Panda Government College of Engineering, Kalahandi, Bhawanipatna 766002, Odisha, India e-mail: [email protected] © Springer Nature Singapore Pte Ltd. 2020 S. Adhikari et al. (eds.), Advances in Structural Engineering and Rehabilitation, Lecture Notes in Civil Engineering 38, https://doi.org/10.1007/978-981-13-7615-3_17

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M. Mishra and K. C. Panda

both of these problems is recycled aggregate concrete (RAC). Aggregates can be produced from the demolition waste. This will not only utilize the waste but also saves the natural resources. Many recycling processes for demolition waste were explored and developed for the use of these recycled aggregates. From previous research studies, it can be observed that the RAC having less strength, more drying shrinkage, creep and less resistance to chloride ion penetration compared to those of conventional vibratory concrete. But this small disadvantage can be recovered by incorporating a certain amount of pozzolanic material. In this present study, silpozz is used as a pozzolanic material in concrete mixture as silpozz contains more silica and it enhances the mechanical properties of concrete. However, silpozz is used as a partially replaced item of cement or as an additional cementitious material in concrete. The use of RCA concrete can lead up to 40% reduction in CS. By seeing the increased volumes of construction, demolition waste, industrial by products and the advantages offered by the use of admixtures in modern concrete, it is considered very beneficial from different prospects with similar performance characteristics to NCA. When proved successful RCA can be substitute for NAC in many applications. The utilization of RCA in the erection area is broad, and it has been used many times ago. Wilmot and Vorobieff [1] also stated that RCA has been used in the road industry for the last 100 years in Australia. They also stated that since the end of World War II, the recycling industry had been well established in Europe. Panda and Bala [2] explained that NCA is partially replaced with RCA by 10, 20, 30 and 40%. The M25 grade concrete mix design was carried out. The strength of SCC decreases with an increase in RCA replacement ratios. SCC marginally achieves required CS up to 30% replacement of RCA. Lin et al. [3] conducted both slump and CS of concrete made with RCA, and they conclude that the concrete has slump of 180 mm and CS of 30.17 MPa at 28 days. According to Levy and Helene [4] concrete made with RCA (20, 50, and 100% replacement) have the same workability and CS as NCA concrete in the range of 20–40 MPa at 28 days. When the NCA is replaced by 20% of the RCA, the result is same and sometimes better behaviour than the reference concrete made with NCA. Sami and Akmal [5] stated that the toughness and soundness test results on RCA show higher percentage less than NCA, but it remained within the acceptable limits. Kheder and Al-Windawi [6] stated that the CS of RAC mostly depends on the w/c ratio of the SCC mix.

2 Experimental Programme 2.1 Details of Using Material For this experimental study, OPC 43 grade, zone III fine aggregate, NCA (20 mm passing), RCA (20 mm passing), silpozz; supplied by N. K. Enterprises, Jharsuguda,

Influence of Silpozz on the Properties of Self-Compacting …

191

Odisha, high-end superplasticizer (SP) base of water-reducing admixture and normal water are used. The RCA have been partially replaced with NCA, i.e. 10 and 20% by its weight and the silpozz has been replaced with cement 10% by its weight in SCC with w/c ratio 0.43%. The details of test conduct in the laboratory for FA and CA are conferred in Table 1. The chemical composition and physical properties of silpozz are conferred in Table 2. The samples of RCA, silpozz and SP are presented in Fig. 1.

2.2 Mix Proportions In this experiment, the SCC property is achieved by reducing CA quantity 35% and adding 35% FA. The SCC mix of M30 was designed without RCA as per EFNARC—2002 and 2005 guidelines. There are two batches of concrete mixes prepared. The first batch is prepared by replacement of 0, 10, 20% of RCA with

Table 1 Details of test conducted in laboratory for FA and CA Characteristics

Value obtained experimentally as per IS 383-1970 [7] for FA

NCA

RCA

Fineness modulus

3.03 (Zone-) sand type

7.00

6.87

Specific gravity

2.67

2.86

2.55

Water absorption

0.40

0.20

0.10

Bulk density (Kg/m3)

1568





Abrasion value (%)



34.78

55.42

Impact value (%)



24.00

29.46

Crushing value (%)



23.30

32.90

Table 2 Details of chemical composition and physical properties of silpozz Chemical composition of silpozz

Physical properties of silpozz

Oxides (%)

Average

Characteristics

Physical properties

SiO2

88.18

Bulk density

0.23 g/cc

Al2 O3

1.61

LOI