Steel-concrete compositebridges

David Collings

"I1 ThomasTelford

Contents

Foreword

Acknowledgements

Notation

IX

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xi

1. General concepts

IntroductionStructural formsMaterialsCodesConcreteSteelComposite actionShear connectors

2. Simple beam bridges

IntroductionInitial sizingExample 2.1Initial design of girderBracing of the steelworkInitial design of the concrete slabInitial shear connector designSafety through designEnvironmental issues

3. Integral bridges

IntroductionSoil-structure interactionExample 3.1Weathering steelCompact sectionsPortal frame structuresExample 3.2Effects of skewExample 3.3

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Painting 42Shrinkage 44Differential temperature 44

4. Continuous bridges 46

Introduction 46Motorway widening 47Moment—shear interaction 49Example 4.1 50Moment rounding 51Cracking of concrete 53Bearing stiffeners 55Precamber 55Natural frequency 57Through-girder bridges 58Example 4.2 60Shear lag 61Fatigue 63

5. Viaducts 66

Introduction 66Concept design 66Example 5.1 68Articulation 69Construction methods 71Deck slab 74

6. Haunches and double composite action 78

Introduction 78Haunches 78Longitudinal shear at changes of section 79Double composite action 80Example 6.1 80Slender webs 81Lightweight concrete 83

7. Box girders 85

Introduction 85Behaviour of boxes 85Diaphragms 87Example 7.1 88Example 7.2 92Noise from bridges 93Shear connectors for composite boxes 94Composite plates 95Example 7.3 97

8. Trusses 98

IntroductionExample 8.1Member typeSteel sections under axial loadJoints in steelworkExample 8.2EnclosureLocal loading of websContinuous trussesHigh-strength steel

9. Arches

IntroductionExample 9.1Composite compression membersExample 9.2Fabrication of curved sectionsNodes in tubular structuresAestheticsTied archesExample 9.3Arch buckling

10. Cable-stayed bridges

IntroductionDeck-stay connectionExample 10.1High-strength concreteBuckling interactionShear connectionTowersTower topExample 10.2Stainless steelStrain-limited composite section

11. Prestressed steel—concrete composite bridges

IntroductionDisplacement of supportsPrestress using tendonsDesign of prestressed composite structuresPrestress lossesExample 11.1DurabilityPrestressed composite box girdersCorrugated websExample 11.2Extra-dosed bridges

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VII

12. Assessment of composite bridges 155

Introduction 155History 155Structure types 157Inspection 157Loads 157Materials 159Testing of the shear connection 160Analysis 160Incidental and partial composite action 161Cased beams 161Strengthening 162Life-cycle considerations 162

Appendix A: Approximate methods 164

Appendix B: Calculation of section properties 165

Section properties for steel sections 165Section properties for steel—concrete composite sections 165Section properties for cracked steel—concrete composite sections withreinforcement 166

Appendix C: Section properties for examples 167

Appendix D: Plastic section properties for steel—concrete compositesections 168

Appendix E: Torsional properties for steel—concrete compositesections 170

Appendix F: Moment-axial load interaction for compact

steel-concrete composite sections 171

References 172

Index 177