[Engineering]

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Acknowledgement

I would take this opportunity to thank my research supervisor, family and friends for their support and guidance without which this research would not have been possible (A, 2002,, 96).

DECLARATION

I, [type your full first names and surname here], declare that the contents of this dissertation/thesis represent my own unaided work, and that the dissertation/thesis has not previously been submitted for academic examination towards any qualification. Furthermore, it represents my own opinions and not necessarily those of the University (A, 2002,, 96).

Signed __________________ Date _________________

Table of Contents

EXECUTIVE SUMMARY6

Problem Statement6

Objectives7

Summary of Work7

Main Findings and Conclusions8

1 INTRODUCTION10

1.1 Background10

1.2 Motivation and Research Objectives13

1.3 Report Organization15

2 ANALYSES OF COMPOSITE OPEN TRAPEZODIAL BOX GIRDER BRIDGES16

2.1 Introduction16

2.2 Choice of Analysis Strategy17

2.3 Program Structure18

2.4 Graphical User Interface18

2.5 Elements Library22

2.5.1 Six DOF Implementation22

2.5.2. Seven DOF Implementation27

2.6 Special Features31

2.6.1 Shear Deformations31

2.6.2 Eccentricity between Shear Center and Centroid37

2.6.3 Support Boundary Conditions38

2.6.4 Implementation using Sparse Matrices41

2.7 Program Verification43

2.7.1 Comparison with closed-form solution43

2.7.2 Comparison with beam element models (ABAQUS)45

2.7.3 Comparison with full shell element models (SAP2000)45

3 WARPING STRESSES IN COMPOSITE CURVED BOX GIRDER BRIDGES56

3.1 Background56

3.2 Non-uniform Torsion56

3.3 Analysis of Existing Bridges60

3.3.1 Geometric properties of closed cross sections60

3.3.2 Bridge models67

3.3.3 Bridge loading and resulting forces68

3.3.4 Stress Calculations71

3.4 Warping Stress Ratio72

3.5 Results74

3.5.1 Normal stresses74

3.5.2 Shear stresses75

3.5.3 Effect of 75

3.6 Design Implications76

3.7 Summary and Conclusions81

4 LIVE LOAD DISTRIBUTION FACTORS FOR COMPOSITE CURVED BOX GIRDERS83

4.1 Introduction83

4.2 Concept of Distribution Factor84

4.3 Analysis Procedure and Model Verification85

4.3.1 Shell Models vs. Grillage Models86

4.3.2 Determination of Distribution Factors87

4.4 Parametric Study93

4.5 Results and Conclusions94

5 ACCESS HATCHES IN CONTINUOUS COMPOSITE OPEN TRAPEZODIAL BOX GIRDER BRIDGES98

5.1 Introduction98

5.2 Practical Constraints for Choosing Access Hole Location99

5.2.1 Strength99

5.2.2 Feasibility100

5.2.3 Accessibility101

5.2.4 Water Leakage101

5.2.5 Impact on Traffic101

5.2.6 Unauthorized Access102

5.2.7. Cost Comparison between Construction on Live Motorway and Green Field103

5.2.8. Errection Sequence &Errection Method107

5.3 Stresses in Curved Box Girder Bridges111

5.4 Low Stress Regions111

5.4.1 Results for Idealized Bridge112

5.4.2 Study of Existing Bridges115

5.5 Effect of Hole Location on Strength of an Existing Bridge116

5.6 Summary and Conclusions119

6 SUMMARY AND CONCLUSIONS121

REFERENCES124

APPENDIX A: SUMMARY OF EXPRESSIONS USED IN COMPUTING GEOMETRIC PROPERTIES127

APPENDIX B: RESEARCH DISSEMINATION131

9.1 Papers Accepted for Publication131

9.2 Papers Submitted for Publication131

Design for Superstructure of New Over Bridge

EXECUTIVE SUMMARY

Problem Statement

Plate girders are commonly used in bridges, interchanges, and ramps. Composite open trapezodial box girders have a number of unique qualities that make them suitable for such applications including: 1) their structural efficiency allows designers to build long slender bridges that have an aesthetically pleasing appearance, and 2) composite box girders are particularly strong in torsion and efficiently resist the large torsional demands created by horizontal bridge curvature and vehicle centrifugal forces.

Analysis and design of composite open trapezodial box bridges is complicated by many factors including: composite interaction between the concrete deck and steel U-girder, local buckling of the thin steel walls making up the box, torsional warping, distortional warping, interaction between different kinds of cross-sectional forces, and the effect of horizontal bridge curvature on both local and global behavior.

Current codes pertaining to analysis and design of curved composite girders are mostly based on experimental and analytical research conducted over 30 years ago as part of project ...