Design of Buildings for Wind: A Guide for ASCE 7–10 Standard Users and Designers of Special Structures

The updated practical guide to the design for wind of low– and medium–rise buildings, tall buildings, and special structures

Design of Buildings for Wind, Second Edition is a practical guide that uses physical and intuitive approaches as well as practical examples to demonstrate how to interpret and use provisions of the ASCE 7–10 Standard and design structures for strength and serviceability. Written by one of the world′s foremost wind engineering experts, Emil Simiu, this unique text is written specifically for designers and structural engineers.

Covering routine buildings, tall buildings, and other structures, Design of Buildings for Wind, Second Edition contains a wealth of step–by–step numerical examples, as well as links to publicly available software, to assist structural engineers in understanding and using the elements of wind and structural engineering required for design. Thoroughly revised and updated to conform to current practice and research, the Second Edition includes:

New coverage of ASCE 7–10 Standard design methods, guiding designers to clearly understand the spirit, letter, and limitations of the provisions and use the design methods with confidence and ease

New focus on tall buildings to help make the analysis and design easier and more transparent

New material on structural reliability and estimation of wind–induced losses

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

Emil Simiu, PE, PhD, is a NIST Fellow and a Fellow at the American Society of Civil Engineers. He served as chairman of its Committee on Wind Effects, Committee on Dynamic Effects, and Committee on the Reliability of Offshore Structures; as senior structural engineer with Severud Associates and Ammann & Whitney, Inc.; and as distinguished research professor at Florida International University′s International Hurricane Research Center. Also a distinguished member of the ASCE Standard Committee on Loads, he was a recipient of the Federal Engineer of the Year award from the National Society of Professional Engineers, and of the 2006 Japan Association for Wind Engineering Prize, given to the outstanding wind engineering publication of the year, for the first edition of Design of Buildings and Bridges for Wind. In addition, Dr. Simiu is the coauthor of Wind Effects on Structures, Third Edition (Wiley).