Theory of Bridge Aerodynamics (eBook)

Title page 3
PREFACE TO 2NDEDITION 6
PREFACE TO 1ST EDITION 7
CONTENTS 8
NOTATION 11
INTRODUCTION 18
General considerations 18
Random variables and stochastic processes 20
Basic flow and structural axis definitions 23
Structural design quantities 26
SOME BASIC STATISTICAL CONCEPTS IN WIND ENGINEERING 30
Time domain and ensemble statistics 32
Threshold crossing and peaks 44
Extreme values 46
Auto spectral density 50
Cross-spectral density 55
The connection between spectra and covariance 57
Coherence function and normalized co-spectrum 59
The spectral density of derivatives of processes 60
Spatial averaging in structural response calculations 61
STOCHASTIC DESCRIPTION OF TURBULENT WIND 69
Mean wind velocity 69
Single Point Statistics of Wind Turbulence 74
The spatial properties of wind turbulence 79
BASIC THEORY OF STOCHASTIC DYNAMIC RESPONSE CALCULATIONS 85
Modal Analysis and Dynamic Equilibrium Equations 85
Single mode single component response calculations 92
Single mode three component response calculations 96
General multi-mode response calculations 100
WIND AND MOTION INDUCED LOADS 107
The buffeting theory 107
Aerodynamic derivatives 113
Vortex shedding 118
WIND INDUCED STATIC AND DYNAMIC RESPONSE CALCULATIONS 125
Introduction 125
The mean value of the response 129
Buffeting response 132
Vortex shedding 158
DETERMINATION OF CROSS SECTIONAL FORCES 173
Introduction 173
The mean value 179
The background quasi–static part 179
The resonant part 198
MOTION INDUCED INSTABILITIES 211
Introduction 211
Static divergence 215
Galloping 216
Dynamic stability limit in torsion 218
Flutter 219
THE BUFFETING THEORY IN A FINITE ELEMENT FORMAT 225
Introduction 225
The element mechanical properties 228
The wind load 236
The global analysis 246
The time invariant static solution 250
The quasi-static solution 250
Dynamic response calculations in frequency domain 254
Frequency domain response calculations in modal coordinates 262
Dynamic response calculations in time domain 267
Appendix A TIME DOMAIN SIMULATIONS 279
Appendix B DETERMINATION OF THE JOINT ACCEPTANCE FUNCTION 293
Appendix C AERODYNAMIC DERIVATIVES FROM SECTION MODEL DECAYS 296
Appendix D DETERMINATION OF INDICIAL FUNCTIONS FROM AERODYNAMIC DERIVATIVES 303
REFERENCES 311
INDEX 313