Contenido Wind Effects on Structures: Modern Structural Design for Wind

Provides structural engineers with the knowledge and practical tools needed to perform structural designs for wind that incorporate major technological, conceptual, analytical and computational advances achieved in the last two decades.

With clear explanations and documentation of the concepts, methods, algorithms, and software available for accounting for wind loads in structural design, it also describes the wind engineer's contributions in sufficient detail that they can be effectively scrutinized by the structural engineer in charge of the design.

Wind Effects on Structures: Modern Structural Design for Wind, 4th Edition is organized in four sections. The first covers atmospheric flows, extreme wind speeds, and bluff body aerodynamics. The second examines the design of buildings, and includes chapters on aerodynamic loads; dynamic and effective wind-induced loads; wind effects with specified MRIs; low-rise buildings; tall buildings; and more. The third part is devoted to aeroelastic effects, and covers both fundamentals and applications. The last part considers other structures and special topics such as trussed frameworks; offshore structures; and tornado effects.

Offering readers the knowledge and practical tools needed to develop structural designs for wind loadings, this book:

Points out significant limitations in the design of buildings based on such techniques as the high-frequency force balance

Discusses powerful algorithms, tools, and software needed for the effective design for wind, and provides numerous examples of application  

Discusses techniques applicable to structures other than buildings, including stacks and suspended-span bridges  
    
Features several appendices on Elements of Probability and Statistics; Peaks-over-Threshold Poisson-Process Procedure for Estimating Peaks; estimates of the WTC Towers’
Response to Wind and their shortcomings; and more

Wind Effects on Structures: Modern Structural Design for Wind, 4th Edition is an excellent text for structural engineers, wind engineers, and structural engineering students and faculty.


Contents

Preface to the Fourth Edition

Introduction

Part I Atmospheric Flows, ExtremeWind Speeds, Bluff Body

Aerodynamics

1 Atmospheric Circulations

1.1 Atmospheric Thermodynamics
   1.1.1 Temperature of the Atmosphere
   1.1.2 Radiation in the Atmosphere
   1.1.3 Compression and Expansion. Atmospheric Stratification
   1.1.4 Molecular and Eddy Conduction
   1.1.5 Condensation ofWater Vapor
1.2 Atmospheric Hydrodynamics
1.3 Windstorms
   1.3.1 Large-Scale Storms
   1.3.2 Local Storms
References

2 The Atmospheric Boundary Layer

2.1 Wind Speeds and Averaging Times
2.2 Equations of Mean Motion in the ABL
2.3 Wind Speed Profiles in Horizontally Homogeneous Flow Over Flat Surfaces
   2.3.1 The Ekman Spiral
   2.3.2 Neutrally Stratified ABL: Asymptotic Approach
   2.3.3 Brunt-Väisäla Frequency. Types of Neutrally Stratified ABLs
   2.3.4 The Logarithmic MeanWind Profile
   2.3.5 Power Law Description of ABLWind Speed Profiles
   2.3.6 ABL Flows in Different Surface Roughness Regimes
   2.3.7 Relation BetweenWind Speeds with Different Averaging Times
2.4 ABL Turbulence in Horizontally Homogeneous Flow Over Smooth Flat Surfaces
   2.4.1 Turbulence Intensities
   2.4.2 Integral Turbulence Scales
   2.4.3 Spectra of TurbulentWind Speed Fluctuations
   2.4.4 Cross-spectral Density Functions
2.5 Horizontally Non-Homogeneous Flows
   2.5.1 Flow Near a Change in Surface Roughness. Fetch and Terrain Exposure
   2.5.2 Wind Profiles over Escarpments
   2.5.3 Hurricane andThunderstormWinds
References

3 ExtremeWind Speeds

3.1 Cumulative Distributions, Exceedance Probabilities, Mean Recurrence Intervals
   3.1.1 Probability of Exceedance and Mean Recurrence Intervals
      3.1.1.1 A Case Study: The Fair Die
      3.1.1.2 Extension to ExtremeWind Speeds
   3.1.2 MixedWind Climates
3.2 Wind Speed Data
   3.2.1 Meteorological and Micrometeorological Homogeneity of the Data
   3.2.2 Directional and Non-DirectionalWind Speeds
   3.2.3 Wind Speed Data Sets
       3.2.3.1 Data in the Public Domain
       3.2.3.2 Data Available Commercially
3.3 N-year Speed Estimation fromMeasuredWind Speeds
   3.3.1 Epochal Versus Peaks-Over-Threshold Approach to Estimation of Extremes
   3.3.2 Extreme Value Distributions andTheir Use inWind Climatology 62
   3.3.3 Wind Speed Estimation by the Epochal Approach
      3.3.3.1 Method of Moments
   3.3.4 Sampling Errors in the Estimation of Extreme Speeds 64
   3.3.5 Wind Speed Estimation by the Peaks-Over-Threshold Approach
   3.3.6 Spatial Smoothing
   3.3.7 Development of LargeWind Speed Datasets
3.4 Tornado Characterization and Climatology
   3.4.1 Tornado Flow Modeling
   3.4.2 Summary of NUREG/CR-4461, Rev. 2 Report [17]
   3.4.3 Design-Basis Tornado for Nuclear Power Plants
References

4 Bluff Body Aerodynamics

4.1 Governing Equations
   4.1.1 Equations of Motion and Continuity
   4.1.2 The Navier–Stokes Equation
   4.1.3 Bernoulli’s Equation
4.2 Flow in a Curved Path: Vortex Flow
4.3 Boundary Layers and Separation
4.4 Wake and Vortex Formations in Two-Dimensional Flow
4.5 Pressure, Lift, Drag, and Moment Effects on Two-Dimensional Structural Forms
4.6 Representative Flow Effects inThree Dimensions
   4.6.1 Cases Retaining Two-Dimensional Features
   4.6.2 Structures inThree-Dimensional Flows: Case Studies
References 1

5 Aerodynamic Testing

5.1 Introduction
5.2 Basic Similarity Requirements
   5.2.1 Dimensional Analysis
   5.2.2 Basic Scaling Considerations
5.3 Aerodynamic Testing Facilities
5.4 Wind Tunnel Simulation of Atmospheric Boundary Layers
   5.4.1 Effect of Type of Spires and Floor Roughness Elements
   5.4.2 Effect of Integral Scale and Turbulence Intensity
   5.4.3 Effects of Reynolds Number Similarity Violation
   5.4.4 Comparisons ofWind Tunnel and Full-Scale Pressure Measurements
5.5 Blockage Effects
5.6 The High-Frequency Force Balance
5.7 Simultaneous Pressure Measurements at Multiple Taps
References

6 ComputationalWind Engineering

6.1 Introduction
6.2 Governing Equations
6.3 DiscretizationMethods and Grid Types
6.4 Initial and Boundary Conditions
   6.4.1 Initial Conditions
   6.4.2 Boundary Conditions
6.5 Solving Equations
6.6 Stability 139
6.7 Turbulent Flow Simulations
   6.7.1 Resolved and Modeled Turbulence
   6.7.2 Direct Numerical Simulation (DNS)
   6.7.3 Large Eddy Simulations (LES)
   6.7.4 Reynolds-Averaged Navier–Stokes Simulation (RANS)
   6.7.5 Hybrid RANS/LES Simulation
   6.7.6 Performance of Turbulence Models
6.8 Verification and Validation. Uncertainty Quantification
   6.8.1 Sources of Inaccuracy in CWE Simulations
   6.8.2 Verification and Validation
   6.8.3 Quantification of Errors and Uncertainties
6.9 CWE versusWind Tunnel Testing
6.10 Best Practice Guidelines
References

7 Uncertainties inWind Engineering Data

7.1 Introduction
7.2 Statistical Framework for Estimating Uncertainties in theWind Loads
7.3 Individual and Overall Uncertainties
   7.3.1 Uncertainties in the Estimation of ExtremeWind Speeds
   7.3.2 Uncertainties in the Estimation of Exposure Factors
   7.3.3 Uncertainties in the Estimation of Pressure Coefficients
   7.3.4 Uncertainties in Directionality Factors
References

Part II Design of Buildings

8 Structural Design forWind

8.1 Modern Structural Design forWind: A Brief History
8.2 Database-Assisted Design
8.3 Equivalent StaticWind Loads
8.4 DAD versus ES


9 StiffnessMatrices, Second-Order Effects, and Influence Coefficients

9.1 Stiffness Matrices
9.2 Second-Order Effects
9.3 Influence Coefficients
References

10 Aerodynamic Loads

10.1 Introduction
10.2 Pressure Tap Placement Patterns and Tributary Areas
10.3 Aerodynamic Loading for Database-Assisted Design
10.4 Peaks of Spatially Averaged Pressure Coefficients for Use in Code Provisions
   10.4.1 PressuresWithin an Area A Contained in a Specified Pressure Zone
   10.4.2 Identifying Areas AWithin a Specified Pressure Zone
10.5 Aerodynamic Pressures andWind-Driven Rain
References

11 Dynamic and EffectiveWind-Induced Loads

11.1 Introduction
11.2 The Single-Degree-of-Freedom Linear System
11.3 Time-Domain Solutions for 3-D Response of Multi-Degree-of-Freedom Systems
   11.3.1 Natural Frequencies and Modes of Vibration
   11.3.2 Solutions of Equations of Motion of Forced System
11.4 Simultaneous Pressure Measurements and EffectiveWind-induced Loads
Reference


12 Wind Load Factors and DesignMean Recurrence Intervals

12.1 Introduction
12.2 Uncertainties in the Dynamic Response
12.3 Wind Load Factors: Definition and Calibration
12.4 Wind Load Factors vs. Individual Uncertainties
   12.4.1 Effect ofWind Speed Record Length
   12.4.2 Effect of Aerodynamic Interpolation Errors
   12.4.3 Number of Pressure Taps Installed on Building Models
   12.4.4 Effect of Reducing Uncertainty in the Terrain Exposure Factor
   12.4.5 Flexible Buildings
   12.4.6 Notes
12.5 Wind Load Factors and Design Mean Recurrence Intervals
References

13 Wind Effects with Specified MRIs: DCIs, Inter-Story Drift, and Accelerations

13.1 Introduction
13.2 DirectionalWind Speeds and Response Surfaces
13.3 Transformation ofWind Speed Matrix into Vectors of LargestWind Effects
   13.3.1 Matrix of Largest DirectionalWind Speeds
   13.3.2 Transformation of Matrix [Uij] into Matrix of Demand-to-Capacity Indexes DCIpk m (Uij)]
   13.3.3 Vector {DCIm,i} = {maxj(DCIpk m (Uij))}
13.4 Estimation of DirectionalWind Effects with Specified MRIs
13.5 Non-DirectionalWind Speeds:Wind Directionality Reduction Factors
13.6 Demand-to-Capacity Indexes
13.7 Inter-Story Drift and Floor Accelerations
References

14 Equivalent StaticWind Loads

14.1 Introduction
14.2 Estimation of Equivalent StaticWind Loads
References

15 Wind-Induced Discomfort in and Around Buildings

15.1 Introduction
15.2 OccupantWind-Induced Discomfort in Tall Buildings
   15.2.1 Human Response toWind-Induced Vibrations
 15.3 Comfort Criteria for Pedestrian AreasWithin a Built Environment
   15.3.1 Wind Speeds, Pedestrian Discomfort, and Comfort Criteria
15.4 Zones of High SurfaceWindsWithin a Built Environment
   15.4.1 Wind Effects Near Tall Buildings
   15.4.2 Wind Speeds at Pedestrian Level in a Basic Reference Case [8]
   15.4.3 Case Studies
15.5 Frequencies of Ocurrence of UnpleasantWinds
   15.5.1 Detailed Estimation Procedure
   15.5.2 Simplified Estimation Procedure
References 248

16 Mitigation of BuildingMotions

16.1 Introduction
16.2 Single-Degree-of-Freedom Systems
16.3 TMDs for Multiple-Degree-of-Freedom Systems
References

17 Rigid Portal Frames

17.1 Introduction
17.2 Aerodynamic andWind Climatological Databases
17.3 Structural System
17.4 Overview of the Design Procedure
17.5 InterpolationMethods
17.6 Comparisons Between Results Based on DAD and on ASCE 7 Standard
   17.6.1 Buildings with Various Eave Heights
   17.6.2 Buildings with Various Roof Slopes
References

18 Tall Buildings

18.1 Introduction
18.2 Preliminary Design and Design Iterations
18.3 Wind Engineering Contribution to the Design Process
18.4 Using the DAD_ESWL Software
   18.4.1 Accessing the DAD_ESWL Software
   18.4.2 Project Directory and its Contents
   18.4.3 Software Activation. Graphical User Interface
18.5 Steel Building Design by the DAD and the ESWL Procedures: Case Studies
   18.5.1 Building Description
   18.5.2 Using the DAD and the ESWL Options
References

Part III Aeroelastic Effects

19 Vortex-Induced Vibrations

19.1 Lock-In as an Aeroelastic Phenomenon
19.2 Vortex-Induced Oscillations of Circular Cylinders
19.3 Across-Wind Response of Chimneys and Towers with Circular Cross Section
References

20 Galloping and Torsional Divergence

20.1 Galloping Motions
   20.1.1 Glauert–Den Hartog Necessary Condition for Galloping Motion
   20.1.2 Modeling of Galloping Motion
   20.1.3 Galloping of Two Elastically Coupled Square Cylinders
20.2 Torsional Divergence
References

21 Flutter

21.1 Formulation of the Two-Dimensional Bridge Flutter Problem in Smooth Flow
21.2 Aeroelastic Lift and Moment Acting on Airfoils
21.3 Aeroelastic Lift, Drag And Moment Acting on Bridge Decks
21.4 Solution of the Flutter Equations for Bridges
21.5 Two-Dimensional Bridge Deck Response to TurbulentWind in the Presence of Aeroelastic Effects
References

22 Slender Chimneys and Towers

22.1 Slender Chimneys with Circular Cross Section
   22.1.1 Slender Chimneys Assumed to be Rigid
   22.1.2 Flexible Slender Chimneys
   22.1.3 Approximate Expressions for the Across-Wind Response
22.2 Aeroelastic Response of Slender Structures with Square and Rectangular Cross Section
22.3 Alleviation of Vortex-Induced Oscillations
References

23 Suspended-Span Bridges

23.1 Introduction
23.2 Wind Tunnel Testing
23.3 Response to Vortex Shedding
23.4 Flutter and Buffeting of the Full-Span Bridge
   23.4.1 Theory
   23.4.2 Example: Critical Flutter Velocity and Buffeting Response of Golden Gate Bridge
23.5 Stay Cable Vibrations
   23.5.1 Cable Vibration Characteristics
   23.5.2 Mitigation Approaches
References

Part IV Other Structures and Special Topics

24 Trussed Frameworks and Plate Girders

24.1 Single Trusses and Girders
24.2 Pairs of Trusses and of Plate Girders
   24.2.1 Trusses Normal toWind
   24.2.2 Trusses Skewed with Respect toWind Direction
   24.2.3 Pairs of Solid Plates and Girders
24.3 Multiple Frame Arrays
24.4 Square and Triangular Towers
24.4.1 Aerodynamic Data for Square and Triangular Towers
References

25 Offshore Structures

25.1 Wind Loading on Offshore Structures
   25.1.1 Wind Loads on Semisubmersible Units
   25.1.2 Wind Loads on a Guyed Tower Platform
25.2 DynamicWind Effects on Compliant Offshore Structures
   25.2.1 TurbulentWind Effects on Tension Leg Platform Surge
References

26 Tensile Membrane Structures

References

27 TornadoWind and Atmospheric Pressure Change Effects

27.1 Introduction
27.2 Wind Pressures
27.3 Atmospheric Pressure Change Loading
27.4 ExperimentalModeling of Tornado-LikeWind Flows
References

28 Tornado- and Hurricane-Borne Missile Speeds

28.1 Introduction
28.2 Tornado-Borne Missile Speeds
   28.2.1 DeterministicModeling of Design-Basis Missile Speeds
   28.2.2 Probabilistic Modeling of Design-Basis Missile Speeds
28.3 Hurricane-BorneMissile Speeds
   28.3.1 Basic Assumptions
   28.3.2 Numerical Solutions
   28.3.3 Simplified Flow Field: Closed Form Solutions
References

Appendices

Appendix A Elements of Probability and Statistics
A.1 Introduction
   A.1.1 Definition and Purpose of ProbabilityTheory
   A.1.2 Statistical Estimation
A.2 Fundamental Relations
   A.2.1 Addition of Probabilities
   A.2.2 Compound and Conditional Probabilities:The Multiplication Rule
   A.2.3 Total Probabilities
   A.2.4 Bayes’ Rule
   A.2.5 Independence
A.3 Random Variables and Probability Distributions
   A.3.1 Random Variables: Definition
   A.3.2 Histograms, Probability Density Functions, Cumulative Distribution Functions
   A.3.3 Changes of Variable
   A.3.4 Joint Probability Distributions
A.4 Descriptors of Random Variable Behavior
   A.4.1 Mean Value,Median,Mode, Standard Deviation, Coefficient of Variation, and Correlation Coefficient
A.5 Geometric, Poisson, Normal, and Lognormal Distributions
   A.5.1 The Geometric Distribution
   A.5.2 The Poisson Distribution
   A.5.3 Normal and Lognormal Distributions
A.6 Extreme Value Distributions
   A.6.1 Extreme Value Distribution Types
       A.6.1.1 Extreme Value Type I Distribution
       A.6.1.2 Extreme Value Type II Distribution
      A.6.1.3 Extreme Value Type III Distribution
   A.6.2 Generalized Extreme Value (GEV) Distribution
A.6.3 Generalized Pareto Distribution (GPD)
A.6.4 Mean Recurrence Intervals (MRIs) for Epochal and Peaks-over-Threshold (POT) Approaches
A.7 Statistical Estimates
A.7.1 Goodness of Fit, Confidence Intervals, Estimator Efficiency
A.7.2 Parameter Estimation for ExtremeWind Speed Distributions
A.8 Monte CarloMethods
A.9 Non-Parametric Statistical Estimates
A.9.1 Single Hazards
A.9.2 Multiple Hazards
References

Appendix B Random Processes

B.1 Fourier Series and Fourier Integrals
B.2 Parseval’s Equality
B.3 Spectral Density Function of a Random Stationary Signal
B.4 Autocorrelation Function of a Random Stationary Signal
B.5 Cross-Covariance Function, Co-Spectrum, Quadrature Spectrum, Coherence
B.6 Mean Upcrossing and Outcrossing Rate for a Gaussian Process
B.7 Probability Distribution of the Peak Value of a Random Signal with Gaussian Marginal Distribution
Reference

Appendix C Peaks-Over-Threshold Poisson-Process Procedure for Estimating Peaks

C.1 Introduction
C.2 Peak Estimation by Peaks-Over-Threshold Poisson-Process Procedure
C.3 Dependence of Peak Estimates by BLUE Upon Number of Partitions
C.4 Summary
References

Appendix D Structural Dynamics

D.1 Introduction
D.2 The Single-Degree-of-Freedom Linear System
D.2.1 Response to a Harmonic Load
D.2.2 Response to an Arbitrary Load
D.2.3 Response to a Stationary Random Load
D.3 Continuously Distributed Linear Systems
D.3.1 Normal Modes and Frequencies: Generalized Coordinates, Mass and Force
D.3.1.1 Modal Equations of Motion
D.3.2 Response to a Concentrated Harmonic Load
D.3.3 Response to a Concentrated Stationary Random Load
D.3.4 Response to Two Concentrated Stationary Random Loads
D.3.5 Effect of the Correlation of the Loads upon the Magnitude of the Response
D.3.6 Distributed Stationary Random Loads
D.4 Example: Along-Wind Response
References

Appendix E Structural Reliability

E.1 Introduction
E.2 The Basic Problem of Structural Safety
E.3 First-Order Second-Moment Approach: Load and Resistance Factors
E.3.1 Failure Region, Safe Region, and Failure Boundary
E.3.2 Safety Indexes
E.3.3 Reliability Indexes and Failure Probabilities
E.3.4 Partial Safety Factors: Load and Resistance Factor Design
E.3.5 Calibration of Safety Index ????,Wind Directionality, and Mean Recurrence Intervals ofWind Effects
E.4 Structural Strength Reserve
E.4.1 Portal Frame Ultimate Capacity UnderWind with Specified Direction
E.4.2 Portal Frame Ultimate Capacity Estimates Based on Multi-Directional Wind Speeds
E.4.3 Nonlinear Analysis of Tall Buildings UnderWind Loads
E.5 Design Criteria for Multi-Hazard Regions
E.5.1 StrongWinds and Earthquakes
E.5.2 Winds and Storm Surge
References

Appendix F World Trade Center Response toWind

F.1 Overview
F.1.1 Project Overview
F.1.2 Report Overview
F.2 NIST-Supplied Documents
F.2.1 RowanWilliams Davies Irwin (RWDI)Wind Tunnel Reports
F.2.2 Cermak Peterka Petersen, Inc. (CPP)Wind Tunnel Report
F.2.3 Correspondence
F.2.4 NIST Report, Estimates ofWind Loads on theWTC Towers, Emil Simiu and Fahim Sadek, April 7, 2004
F.3 Discussion and Comments
F.3.1 General
F.3.2 Wind Tunnel Reports andWind Engineering
F.3.2.1 CPPWind Tunnel Report
F.3.2.2 RWDIWind Tunnel Report
F.3.2.3 Building Period used inWind Tunnel Reports
F.3.2.4 NYCBCWind Speed 484
F.3.2.5 IncorporatingWind Tunnel Results in Structural Evaluations
F.3.2.6 Summary
F.3.3 NIST RecommendedWind Loads
Index