Ultimate Capacity of Steel Angles Subjected to Eccentric Compressive Load

125 Pages·2015·2.55 MB·English

Ultimate Capacity of Steel Angles Subjected to
Eccentric Compressive Load

by
Iftesham Bashar

MASTER OF SCIENCE IN CIVIL ENGINEERING (STRUCTURAL)

Department of Civil Engineering
BANGLADESH UNIVERSITY OF ENGINEERING AND TECHNOLOGY

2012
Ultimate Capacity of Steel Angles Subjected to
Eccentric Compressive Load

by
Iftesham Bashar

A thesis submitted to the Department of Civil Engineering of Bangladesh University of
Engineering and Technology, Dhaka, in partial fulfillment of the requirements for the
degree of

MASTER OF SCIENCE IN CIVIL ENGINEERING (STRUCTURAL)

2012
The thesis titled “Ultimate Capacity of Steel Angles Subjected to Eccentric
Compressive Load” submitted by Iftesham Bashar, Student No. 100704337F, and
Session: October 2007 has been accepted as satisfactory in partial fulfillment of the

requirement for the degree of M.Sc. Engg. (Civil and Structural) on 25th January, 2012.

BOARD OF EXAMINERS

______________________________________
Dr. Khan Mahmud Amanat Chairman
Professor (Supervisor)
Department of Civil Engineering, BUET,
Dhaka-1000

______________________________________
Dr. Md. Mujibur Rahman Member
Professor and Head (Ex-officio)
Department of Civil Engineering, BUET,
Dhaka-1000

______________________________________
Dr. A. M. M. Taufiqul Anwar Member
Professor
Department of Civil Engineering, BUET,
Dhaka-1000

_____________________________________
Dr. Mahbuba Begum Member
Associate Professor
Department of Civil Engineering, BUET,
Dhaka-1000

______________________________________
Dr. Alamgir Habib Member
Professor (Retd.) (External)
Department of Civil Enginerring, BUET,
Dhaka-1000
Apartment # 2A, House # 124, Road # 9A
Dhanmondi, Dhaka.
DECLARATION

It is declared that, except where specific references are made to other investigators, the
work embodied in this thesis paper is the result of investigation carried out only by the
author under the supervision of Dr. Khan Mahmud Amanat, Professor, Department of
Civil Engineering, BUET. Neither the thesis nor any part of it has been submitted to or
is being submitted elsewhere for any other purposes.

Iftesham Bashar
(Author)

i
Dedicated
to
My Parents

ii
A
CKNOWLEDGEMENTS

I would like to express my heartfelt gratitude to the Almighty Allah for each and
every achievement of my life.

I would like to express my sincerest regards to my thesis supervisor, Dr. Khan
Mahmud Amanat for his guidance and encouragement during the course of this
research and throughout my master’s education. I am greatly indebted to him for all
his adept guidance, affectionate assistance, and enthusiastic encouragement
throughout the progress of this thesis. It would have been impossible to carry out this
study without his dynamic direction and critical judgment of the progress.

I wish to express my deepest gratitude to the Department of Civil Engineering,
BUET, the Head of the Department of Civil Engineering and all the members of the
BPGS committee to give me such a great opportunity of doing my M.Sc. and this
contemporary research work on eccentrically loaded single steel angles. I would also
like to specially thank the members of the defense board for their time and patience.

I greatly acknowledge all my friends and staffs of the university for their assistance
and encouragement. Finally, I would like to thank my parents and my family
members, for their undying love, encouragement and support at all stages of my life.
I would like to convey my special thanks to my mother for her perpetual patience
caring my babies while I was busy in my research works. The achievement of this
goal would have been impossible without their blessings.

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Table of Contents

Page
No.
Declaration i
Dedication ii
Acknowledgements iii
Abstract iv

Chapter 1 Introduction

1.1 General 1
1.2 Background and Research Significance 1
1.3 Objectives of the Present Study 3
1.4 Methodology of the Study 3
1.5 Organization of the Thesis 4

Chapter 2 Literature Review

2.1 Introduction 5
2.2 Ultimate Compressive Load Capacity of Structural Steel Members 5
2.3 Development of Column Buckling Theory 8
2.4 Eccentrically Loaded Column Buckling Theory 11
2.4.1 General 11
2.4.2 Development of Eccentrically Loaded Column Buckling 12
Theory
2.4.2.1 Theoretical Investigations 12
2.4.2.2 Experimental Investigations 14
2.4.2.3 Numerical Investigations 17
2.5 Experiment of Elgaaly et al (1991) 18

2.5.1 Test Procedure 20
2.5.2 Test Results (Elgaaly et al 1991) 20
2.6 Code Provisions to Determine Ultimate Compressive Load Capacity 23
of Structural Steel Angles
2.6.1 ASCE Standard 10-97: Design of Latticed Steel 23
Transmission Structures
2.6.2 AISC 2005 Specification 25
2.6.3 BS (8100) Formula (1999) 26
2.6.4 AASHTO Formula 29
2.6.5 IS Code Formula 29
2.6.6 CRC Formula 31
2.7 Example Calculation 32
2.8 Remarks 41

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Chapter 3 Methodology for Finite Element Analysis

3.1 Introduction 43
3.2 Finite Element Modeling of the Truss System 43
3.2.1 Modeling Methodology 43
3.2.2 Material Properties 52
3.2.3 Loading and Boundary Conditions 53
3.2.3.1 Restraints 53
3.2.3.2 Loads 53
3.2.4 Meshing 53
3.2.5 Solution Method 55
3.2.6 Mesh Sensitivity 56
3.3 Typical Analysis Results 56
3.3.1 Typical Load-Deflection Behavior 56
3.3.2 Deflected Shapes 57
3.4 Validation of Finite Element Model 60

Chapter 4 Results and Discussions

4.1 Introduction 62
4.2 Principal Features of Present Analysis 62
4.3 Presentation of Results 63
4.3.1 Axial Force vs Lateral Displacement Response 63
4.3.2 Deformation Characteristics of the Target Angle 66
4.3.2.1 General 66
4.3.2.2 Initial Stage 67
4.3.2.3 Final Stage 68
4.3.3 Comparative Results 69
4.3.3.1 Typical Comparative Load vs Deflection Graphs 69
4.3.3.2 Correlation between Test and Present Study 72
4.3.3.2 Comparison with Codes and Discussions 75
4.4 Interpretation and Explanation of Observations 80
4.5 Remarks 84

Chapter 5 Conclusion

5.1 General 85
5.2 Findings 85
5.3 Scpoe for Future Investigation 86

References 87

Appendices
Appendix-A : Results for single bolted angles 91
Results for double bolted angles 92

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Appendix-B : Ultimate Capacity of Angles Using Code Formulas 93
Appendix-C : Comparative Results of Single Bolted Angles 103
Comparative Results of Double Bolted Angles 105

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