Cable Supported Bridges: Concept and Design

ISBN-13: 9780470666289 / Angielski / Twarda / 2012 / 600 str.

Niels J. Gimsing; Christos T. Georgakis

Opis

Fourteen years after its last edition, this work has been significantly updated with corrections and brand new imagery throughout. Since the appearance of the second edition the dynamic response of cable supported bridges has increased in focus, and this development is recognized with a new chapter on dynamic actions.

Recenzje

Pleasingly, this book is comprehensively referenced for those wishing to delve into further detail. While not a manual for detailed design, the contents of the book provide a comprehensive knowledge base for students and experienced engineers seeking to expand their understanding of these structures, which themselves continually challenge the boundaries of what is possible.   ( Engineering and Computational Mechanics , 11 October 2013) The book is well organised into components: cables, pylons and anchorages, and goes into every possible detail The book strikes a perfect balance between theory and practice. Professors Gimsing and Georgakis set out to give us an authoritative book about the evolution, trends and technical response of cable–supported bridges, and they have achieved that well.   ( The Structural Engineer , 1 April 2012) Comprehensively updated to discuss improvements in technology in the fourteen years since its last printing, the third edition of this volume on the theory and design of cable supported bridges provides a detailed, element–by–element discussion of the core principles of suspension bridge design.   ( Book News , 1 April 2012)    

Spis treści

Preface to the Third Edition ix

Introduction 1

1 Evolution of Cable Supported Bridges 7

2 Cables 85

2.1 Basic Types of Cables 85

2.1.1 Helical bridge strands (spiral strands) 85

2.1.2 Locked–coil strands 87

2.1.3 Parallel–wire strands for suspension bridge main cables 88

2.1.4 New PWS stay cables 90

2.1.5 Parallel–strand stay cables 91

2.1.6 Bar stay cables 93

2.1.7 Multi–strand stay cables 94

2.1.8 Parallel–wire suspension bridge main cables 97

2.1.9 Comparison between different cable types 101

2.2 Corrosion Protection 102

2.2.1 Suspension bridge main cables 102

2.2.2 Stay cables 105

2.3 Mechanical Properties 109

2.3.1 Static strength 109

2.3.2 Relaxation 111

2.3.3 Fatigue strength 111

2.3.4 Hysteresis of helical strands 113

2.4 The Single Cable as a Structural Element 115

2.4.1 Transversally loaded cable 115

2.4.2 Axially loaded cable 126

2.5 Static Analysis of Cables 131

2.5.1 Equation of state for a cable subjected to vertical load 132

2.5.2 Stay cable under varying chord force 135

2.5.3 Limit length and efficiency ratio of a stay cable 143

2.6 Bending of Cables 148

2.7 Dynamic Behaviour of the Single Cable 157

3 Cable System 165

3.1 Introduction 165

3.1.1 Pure cable systems 165

3.1.2 Cable steel quantity comparison 170

3.1.3 Stability of the cable system 173

3.2 Suspension System 179

3.2.1 Dead load geometry 179

3.2.2 Preliminary cable dimensions 180

3.2.3 Quantity of cable steel 182

3.2.4 Quantity in the pylon 184

3.2.5 Total cost of cable system and pylon 185

3.2.6 Optimum pylon height 185

3.2.7 Size effect 187

3.2.8 Structural systems 188

3.3 Fan System 202

3.3.1 Anchor cable 202

3.3.2 Preliminary cable dimensions 205

3.3.3 Quantity of cable steel 206

3.3.4 Quantity in the pylon 208

3.3.5 Simplified expressions 208

3.3.6 Total cost of cable systems and pylons 209

3.3.7 Comparison between suspension and fan system 209

3.3.8 Inclined pylons 210

3.3.9 Deformational characteristics 213

3.3.10 Structural systems 217

3.3.11 Reduction of sag variations 221

3.4 Harp System 222

3.4.1 Dead load geometry 225

3.4.2 Intermediate supports 226

3.4.3 Preliminary cable dimensions 227

3.4.4 Quantity of cable steel 229

3.4.5 Quantity of the pylon 229

3.4.6 Simplified expressions 231

3.4.7 Total cost 231

3.4.8 Structural systems 231

3.5 Hybrid Suspension and Cable Stayed System 235

3.6 Multi–Span Cable System 239

3.6.1 True multi–span cable supported bridges 241

3.6.2 Non–traditional multi–span suspension bridges 246

3.6.3 Fixing of column–type pylons to piers 249

3.6.4 Triangular pylon structures 250

3.6.5 Horizontal tie cable between pylon tops 258

3.6.6 Comparison between deflections of different multi–span cable stayed systems 261

3.7 Cable Systems under Lateral Loading 265

3.8 Spatial Cable Systems 272

3.9 Oscillation of Cable Systems 278

3.9.1 Global oscillations 278

4 Deck (Stiffening Girder) 287

4.1 Action of the Deck 287

4.1.1 Axial stiffness 287

4.1.2 Flexural stiffness in the vertical direction 287

4.1.3 Flexural stiffness in the transverse direction 289

4.1.4 Torsional stiffness 291

4.2 Supporting Conditions 291

4.3 Distribution of Dead Load Moments 299

4.3.1 The dead load condition 302

4.4 Cross Section 310

4.4.1 Bridge floor 310

4.4.2 Cross section of the deck 310

4.4.3 Cross section of stiffening trusses 328

4.5 Partial Earth Anchoring 339

4.5.1 Limit of span length for self–anchored cable stayed bridges 343

4.5.2 Axial compression in the deck of the self anchored cable stayed bridge 344

4.5.3 Lateral bending of the deck 346

4.5.4 Partial earth anchoring of a cable stayed bridge 346

4.5.5 Improving the lateral stability 348

4.5.6 Construction procedure for partially earth anchored cable stayed bridges 349

5 Pylons 353

5.1 Introduction 353

5.2 Structural Behaviour of the Pylon 353

5.3 Pylons Subjected Primarily to Vertical Forces from the Cable System 367

5.4 Pylons Subjected to Longitudinal Forces from the Cable System 399

5.5 Cross Section 405

6 Cable Anchorage and Connection 413

6.1 Anchoring of the Single Strand 413

6.2 Connection between Cable and Deck 427

6.3 Connection between Main Cable and Hanger 433

6.4 Connection between Cable and Pylon 442

6.5 Connection between Cable and Anchor Block 452

7 Erection 463

7.1 Introduction 463

7.2 Construction of Pylons 463

7.3 Erection of Suspension Bridge Main Cables 472

7.4 Erection of Stay Cables 486

7.5 Deck Erection – Earth Anchored Suspension Bridges 489

7.6 Deck Erection – Self Anchored Cable Stayed Bridges 501

8 Aerodynamics 517

8.1 Historical Overview 517

8.1.1 Nineteenth–century bridge failures 517

8.1.2 Tacoma Narrows Bridge collapse 517

8.1.3 The Carmody Board 520

8.1.4 The Fyksesund Bridge 520

8.2 The Bridge Deck and Pylon 520

8.2.1 Torsional divergence 520

8.2.2 Coupled flutter 524

8.2.3 Buffeting 526

8.2.4 Vortex–shedding 531

8.2.5 Wind tunnel testing 532

8.2.6 During construction 537

8.2.7 Effects of vehicles 538

8.2.8 Pylon aerodynamics 538

8.2.9 Vibration control 541

8.2.10 Future trends 543

8.3 Cables 544

8.3.1 Introduction 544

8.3.2 Incidences of wind–induced cable vibrations 544

8.3.3 Rain–wind–induced vibrations 545

8.3.4 Dry galloping 546

8.3.5 Scruton number 549

8.3.6 Wake galloping 550

8.3.7 Aerodynamic countermeasures 551

8.3.8 Mechanical damping 583

8.3.9 Cable aerodynamic damping 557

8.3.10 Cross ties 557

9 Particular Issues 559

9.1 Pedestrian–Induced Vibrations 559

9.1.1 Lateral vibrations 559

9.1.2 Vertical vibrations 562

9.1.3 Serviceability limit states 565

9.1.4 Vibration control 567

9.2 Seismic Design 568

9.2.1 Earthquake intensity 569

9.2.2 Pylon design 569

9.2.3 Deck design 571

9.2.4 Foundations 571

9.2.5 Seismic analysis 572

9.3 Structural Health Monitoring 573

9.3.1 Equipment 573

9.4 Snow and Ice Removal and Prevention Systems 575

9.4.1 Mechanical removal 575

9.4.2 Thermal systems 577

9.4.3 Passive protection 577

References 579

Index 587

O autorze

Niels Jørgen Gimsing & Christos Georgakis, Technical University of Denmark, Lyngby
Professor Gimsing is Professor Emeritus in the Department of Civil Engineering at the Technical University of Denmark and a Consulting Bridge Engineer. He consulted on the design for numerous landmark bridges including the Femern Bridge, third bridge across the Firth of Forth in Scotland, the Messina Strait Bridge and the 47km long motorway bridge across the Gulf of Thailand, and was a Finalist in the Millennium Bridge Competition for a pedestrian bridge across the Thames at St. Paul′s Cathedral. He has won numerous design, teaching and research awards for his work within the structural engineering community and is the author of Cable Supported Bridges 2e (Wiley, 1997) and co–author of The Messina Strait Bridge (CRC, 2009).

Dr. Christos Georgakis is Associate Professor in Structural Engineering and Prof Gimsing s teaching successor at DTU. He has particular experience in relation to dynamic actions from his work at the Wind Tunnel Laboratory in Copenhagen and is also involved in several research projects dealing with the dynamics of slender bridges such as the Millennium Bridge in London.

Blurb

Fourteen years on from its last edition, Cable Supported Bridges: Concept and Design, Third Edition, has been significantly updated with new material and brand new imagery throughout. Since the appearance of the second edition, the focus on the dynamic response of cable supported bridges has increased, and this development is recognised with two new chapters, covering bridge aerodynamics and other dynamic topics such as pedestrian–induced vibrations and bridge monitoring.

This book concentrates on the synthesis of cable supported bridges, suspension as well as cable stayed, covering both design and construction aspects. The emphasis is on the conceptual design phase where the main features of the bridge will be determined. Based on comparative analyses with relatively simple mathematical expressions, the different structural forms are quantified and preliminary optimization demonstrated. This provides a first estimate on dimensions of the main load carrying elements to give in an initial input for mathematical computer models used in the detailed design phase.

Key features:

• Describes evolution and trends within the design and construction of cable supported bridges
• Describes the response of structures to dynamic actions that have attracted growing attention in recent years
• Highlights features of the different structural components and their interaction in the entire structural system
• Presents simple mathematical expressions to give a first estimate on dimensions of the load carrying elements to be used in an initial computer input

This comprehensive coverage of the design and construction of cable supported bridges provides an invaluable, tried and tested resource for academics and engineers.