Covers the new simplified design methods of ASCE 7-10, guiding designers to clearly und
Table of Contents
PREFACE xi PART I INTRODUCTION 1
1 OVERVIEW 3
PART II GUIDE TO THE ASCE 7-10 STANDARD PROVISIONS ON WIND LOADS 7
2 ASCE 7-10 WIND LOADING PROVISIONS 9
2.1 Introduction / 9
2.2 ASCE 7-10 Standard: An Overview / 10
2.3 Organization of the Guide: Chapters 3 to 9 / 19
3 REGULAR AND SIMPLIFIED APPROACH: RISK CATEGORY, BASIC WIND SPEED, ENCLOSURE, EXPOSURE, TOPOGRAPHIC FACTOR 21
3.1 Risk Category (ASCE Table 1.5-1) / 21
3.2 Basic Wind Speed V (ASCE Sect. 26.5, ASCE Figs. 26.5.-1a, b, c) / 22
3.3 Enclosure Classification (ASCE Sects. 26.2 and 26.10) / 23
3.4 Exposure Category (ASCE Sect. 26.7) / 24
3.5 Topographic Factor Kzt (ASCE Sect. 26.8, ASCE Fig. 26.8-1) / 27
4 REGULAR APPROACH: STEPS COMMON TO ALL BUILDINGS/OTHER STRUCTURES (MWFRS AND C&C) 31
4.1 Introduction / 31
4.2 Regular Approach: Steps Common to All Buildings and Other Structures (MWFRS and C&C) / 32
5 REGULAR APPROACH: BUILDINGS, PARAPETS, OVERHANGS (‘‘DIRECTIONAL’’ PROCEDURE), MWFRS 37
5.1 Introduction / 37
5.2 Regular Approach: Enclosed or Partially Enclosed Buildings of All Heights, MWFRS / 37
5.3 Regular Approach: Roof Overhangs and Parapets, MWFRS / 53
5.4 Regular Approach: Open Buildings with Monoslope, Pitched, or Troughed Free Roofs, MWFRS / 55
6 REGULAR APPROACH: LOW-RISE BUILDINGS, PARAPETS, OVERHANGS (‘‘ENVELOPE’’ PROCEDURE), MWFRS 57
6.1 Net Pressures on Walls and Roof / 57
6.2 Comparison Between Results Based on ASCE Sects. 27.4.1 and 28.4.1 / 62
6.3 Regular Approach: Parapets and Roof Overhangs, MWFRS / 63
7 REGULAR APPROACH: STRUCTURES OTHER THAN BUILDINGS, MWFRS 65
7.1 Solid Freestanding Walls and Solid Signs / 65
7.2 Open Signs, Lattice Frameworks, Trussed Towers / 69
7.3 Chimneys, Tanks, Rooftop Equipment, and Similar Structures / 74
7.4 Solid Attached Signs / 75
7.5 Rooftop Structures and Equipment on Buildings / 77
8 SIMPLIFIED APPROACH: ENCLOSED SIMPLE DIAPHRAGM BUILDINGS, PARAPETS, OVERHANGS (MWFRS) 81
8.1 Simplified Approach: Class 1 Buildings, Walls and Roof, MWFRS / 81
8.2 Simplified Approach: Parapets, MWFRS / 85
8.3 Simplified Approach: Roof Overhangs, MWFRS / 85
8.4 Simplified Approach: Class 2 Buildings, Walls and Roof, MWFRS / 86
8.5 Simplified Approach: Simple Diaphragm Low-Rise Buildings, MWFRS / 90
9 REGULAR AND SIMPLIFIED APPROACHES: C&C 95
9.1 Introduction / 95
9.2 Regular Approach / 95
9.3 Simplified Approaches / 105
PART III WIND ENGINEERING FUNDAMENTALS 107
10 ATMOSPHERIC CIRCULATIONS 109
10.1 Atmospheric Hydrodynamics / 109
10.2 Windstorms / 113
11 THE ATMOSPHERIC BOUNDARY LAYER 117
11.1 Wind Speeds and Averaging Times / 118
11.2 Wind Speed Profiles / 121
11.3 Atmospheric Turbulence / 130
12 EXTREME WIND SPEEDS AND WIND-INDUCED EFFECTS 137
12.1 Wind Speed Data / 138
12.2 Cumulative Distributions, Exceedance Probabilities, Mean Recurrence Intervals / 141
12.3 Parametric Estimates of N-Year Wind Speeds; Closed Form Estimators; Software / 143
12.4 Probabilistic Estimates of Wind Effects Based on Nondirectional and Directional Wind Speed Data / 149
12.5 Development of Directional Databases of Hurricane Wind Speeds / 153
12.6 Development of Directional Databases of Non-Hurricane Wind Speeds / 155
12.7 Non-Parametric Statistics, Application to One-Dimensional Time Series / 157
12.8 Error Estimates / 159
13 BLUFF BODY AERODYNAMICS BASICS; AERODYNAMIC TESTING 163
13.1 Introduction / 163
13.2 Bluff Body Aerodynamics / 163
13.3 Aerodynamic Testing / 173
13.4 Low-Frequency Turbulence and Aerodynamic Pressures on Residential Homes / 183
14 STRUCTURAL DYNAMICS 185
14.1 Introduction / 185
14.2 The Single-Degree-of Freedom Linear System / 186
14.3 Continuously Distributed Linear Systems / 190
14.4 Time Domain Solutions for Three-Dimensional Dynamic Response / 199
15 AEROELASTICITY 203
15.1 Introduction / 203
15.2 Vortex-Induced Oscillations / 205
15.3 Galloping / 206
15.4 Flutter / 210
16 STRUCTURAL RELIABILITY UNDER WIND LOADING 217
16.1 Introduction / 217
16.2 First-Order Second-Moment Approach, Load and Resistance Factors / 220
16.3 Dependence of Wind Effects on Wind Directionality / 225
16.4 Structural Strength Reserve / 226
16.5 Design Criteria for Multi-Hazard Regions / 228
16.6 Individual Uncertainties and Overall Uncertainty in the Estimation of Wind Effects / 229
16.7 Calibration of Design MRIs in the Presence of Dynamic Effects or of Large Knowledge Uncertainties / 232
17 LOSS ESTIMATION 237
17.1 Introduction / 237
17.2 Elements of Damage Estimation Procedures / 238
17.3 Loss Estimation / 245
PART IV WIND EFFECTS ON BUILDINGS 247
18 RIGID BUILDINGS 249
18.1 Introduction / 249
18.2 Database-Assisted Design (DAD) / 252
18.3 Wind Directionality Effects / 258
18.4 Uncertainties in the Estimation of Wind Effects / 259
19 TALL BUILDINGS 261
19.1 Introduction / 261
19.2 High-Frequency Force Balance Approach (HFFB) / 263
19.3 Aeroelastic Effects. Testing Based on Strain Measurements / 265
19.4 Database-Assisted Design / 269
19.5 Serviceability Requirements / 278
19.6 Preliminary Estimates of Flexible Building Response / 279
PART V APPENDICES 287
APPENDIXA1 RANDOM PROCESSES 289
A1.1 Fourier Series and Fourier Integrals / 290
A1.2 Parseval’s Equality / 291
A1.3 Spectral Density Function of a Random Stationary Signal / 292
A1.4 Autocorrelation Function of a Random Stationary Signal / 293
A1.5 Cross-Covariance Function, Co-Spectrum, Quadrature Spectrum, Coherence / 295
A1.6 Mean Upcrossing and Outcrossing Rate for a Gaussian Process / 296
A1.7 Probability Distribution of the Peak Value of a Normally Distributed Random Signal / 297
A1.8 Probability Distribution of the Peak Value of a Non-Gaussian Random Signal / 298
APPENDIXA2 MEAN WIND PROFILES AND ATMOSPHERIC BOUNDARY LAYER DEPTH 301
A2.1 Equations of Balance of Momenta within the Atmospheric Boundary Layer / 301
A2.2 The Turbulent Ekman Layer / 302
APPENDIXA3 SPECTRA OF TURBULENT VELOCITY FLUCTUATIONS, KOLMOGOROV HYPOTHESES 307
APPENDIXA4 WIND DIRECTIONALITY EFFECTS, OUTCROSSING AND SECTOR-BY-SECTOR APPROACHES 311
A4.1 Approach Based on the Outcrossing of the Limit-State Boundary / 311
A4.2 The Sector-By-Sector Approach [18-10] / 313
APPENDIXA5 REPORT ON ESTIMATION OF WIND EFFECTS ON THE WORLD TRADE CENTER TOWERS 315
REFERENCES 323
INDEX 333
