Wind forces from various types of extreme wind events continue to generate ever-increasing damage to buildings and other structures. Wind Loading of Structures, Third Edition fills an important gap as an information source for practicing and academic engineers alike, explaining the principles of wind loads on structures, including the relevant aspects of meteorology, bluff-body aerodynamics, probability and statistics, and structural dynamics
A Definitive Up-to-Date Reference
Wind forces from various types of extreme wind events continue to generate ever-increasing damage to buildings and other structures. Wind Loading of Structures, Third Edition fills an important gap as an information source for practicing and academic engineers alike, explaining the principles of wind loads on structures, including the relevant aspects of meteorology, bluff-body aerodynamics, probability and statistics, and structural dynamics.
Written in Line with International Standards
Among the unique features of the book are its broad view of the major international codes and standards, and information on the extreme wind climates of a large number of countries of the world. It is directed towards practicing (particularly structural) engineers, and academics and graduate students.
The main changes from the earlier editions are:
Discussion of potential global warming effects on extreme events
More discussion of tornados and tornado-generated damage
A rational approach to gust durations for structural design
Expanded considerations of wind-induced fatigue damage
Consideration of aeolian vibrations of suspended transmission lines
Expansion of the sections on the cross-wind response of tall slender structures
Simplified approaches to wind loads on "porous" industrial, mining, and oil/gas structures
A more general discussion of formats in wind codes and standards
Not dedicated to a specific code or standard, Wind Loading of Structures, Third Edition highlights the general format and procedures related to all major codes and standards, addresses structures of various types, and presents you with topics not typically covered in traditional texts such as internal pressures, fatigue damage by wind forces, and equivalent static wind load distributions.
Contents
Preface to the first edition
Preface to the second edition
Preface to the third edition
1 The nature of wind storms and wind-induced damage
1.1 Introduction
1.2 Meteorological aspects
1.2.1 Pressure gradient
1.2.2 Coriolis force
1.2.3 Geostrophic wind
1.2.4 Gradient wind
1.2.5 Frictional effects
1.3 Types of wind storms
1.3.1 Gales from large depressions
1.3.2 Tropical cyclones
1.3.3 Thunderstorms
1.3.4 Tornadoes
1.3.5 Downbursts
1.3.6 Downslope winds
1.4 Wind damage
1.4.1 Recent history of wind loss and damage
1.5 Wind-generated debris
1.5.1 Threshold of flight
1.5.2 Trajectories of compact objects
1.5.3 Trajectories of sheet and rod objects
1.5.4 Standardised missile-testing criteria
1.6 Wind storm damage and loss prediction
1.6.1 Hazard models
1.6.2 Vulnerability curves
1.6.3 Damage produced by flying debris
1.7 Hurricane-damage modelling
1.8 Predicted effects of climate change
1.9 Summary
1.10 The following chapters and appendices
References
2 Prediction of design wind speeds and structural safety
2.1 Introduction and historical background
2.2 Principles of extreme value analysis
2.2.1 The GEV Distribution
2.2.2 Return period
2.2.3 Separation by storm type
2.2.4 Simulation methods for tropical cyclone wind speeds
2.2.5 Compositing data from several stations
2.2.6 Correction for gust duration
2.2.7 Wind direction effects and wind direction multipliers
2.3 Extreme wind estimation by the Type I Distribution
2.3.1 Gumbel’s method
2.3.2 Gringorten’s method
2.3.3 Method of Moments
2.3.4 Example of fitting the Type I Distribution to annual maxima
2.3.5 General penultimate distribution
2.4 The peaks-over-threshold approach
2.4.1 Example of the use of the ‘peaks over threshold’ method
2.4.2 Extreme winds by direction sector
2.5 Parent wind distributions
2.6 Wind loads and structural safety
2.6.1 Limit states design
2.6.2 Probability of failure and the safety index
2.6.3 Nominal return period for design wind speeds
2.6.4 Uncertainties in wind load specifications
2.7 Wind load factors
2.8 Summary
References
3 Strong wind characteristics and turbulence
3.1 Introduction
3.2 Mean wind speed profiles
3.2.1 The ‘Logarithmic Law’
3.2.2 The ‘Power Law’
3.2.3 Mean wind profiles over the ocean
3.2.4 Relationship between upper level and surface winds
3.2.5 Mean wind profiles in tropical cyclones
3.2.6 Wind profiles in thunderstorm winds
3.2.7 Wind profiles in tornadoes
3.3 Turbulence
3.3.1Turbulence intensities
3.3.2 Probability density
3.3.3 Gust wind speeds and gust factors
3.3.4 Wind spectra
3.3.5 Correlation
3.3.6 Co-spectrum and coherence
3.3.7 Turbulence in a downdraft
3.4 Modification of wind flow by topography
3.4.1 General effects of topography
3.4.2 Topographic multipliers
3.4.3 Shallow hills
3.4.4 Steep hills, cliffs and escarpments
3.4.5 Effect of topography on tropical cyclones and thunderstorm winds
3.5 Change of terrain
3.6 Weakening of a tropical cyclone after a coast crossing
3.7 Other sources
3.8 Summary
References
4 Basic bluff-body aerodynamics
4.1 Flow around bluff bodies
4.2 Pressure and force coefficients
4.2.1 Bernoulli’s equation
4.2.2 Force coefficients
4.2.3 Dependence of pressure and force coefficients
4.2.4 Reynolds Number
4.3 Flat plates and walls
4.3.1 Flat plates and walls normal to the flow
4.3.2 Flat plates and walls inclined to the flow
4.4 Rectangular prismatic shapes
4.4.1 Drag on two-dimensional rectangular prismatic shapes
4.4.2 Effect of aspect ratio
4.4.3 Effect of turbulence
4.4.4 Drag and pressures on a cube and finite-height prisms
4.4.5 Jensen Number
4.5 Circular cylinders
4.5.1 Effects of Reynolds Number and surface roughness
4.5.2 Effect of aspect ratio
4.6 Fluctuating forces and pressures
4.6.1 Introduction
4.6.2 The Quasi-steady assumption
4.6.3 Body-induced pressure fluctuations and vortex-shedding forces
4.6.4 Fluctuating pressure and force coefficients
4.6.5 Correlation length
4.6.6 Total fluctuating forces on a slender body
4.7 Summary
References
5 Resonant dynamic response and effective static load distributions
5.1 Introduction
5.2 Principles of dynamic response
5.3 The random vibration or spectral approach
5.3.1 Along-wind response of a single-degree-of-freedom structure
5.3.2 Gust response factor
5.3.3 Peak factor
5.3.4 Dynamic response factor
5.3.5 Influence coefficient
5.3.6 Along-wind response of a structure with distributed mass: modal analysis
5.3.7 Along-wind response of a structure with distributed mass:separation of background and resonant components
5.3.8 Along-wind response to non-stationary (transient) winds
5.4 Effective static loading distributions
5.4.1 Introduction
5.4.2 Mean load distributions
5.4.3 Background-loading distributions
5.4.4 Load distributions for resonant response(single resonant mode)
5.4.5 Combined load distribution
5.5 Aeroelastic forces
5.5.1 Aerodynamic damping
5.5.2 Galloping
5.5.3 Flutter
5.5.4 Lock-in
5.6 Fatigue under wind loading
5.6.1 Metallic fatigue
5.6.2 Narrow-band fatigue loading
5.6.3 Wide-band fatigue loading
5.6.4 Effect of varying wind speed
5.6.5 Total accumulated fatigue damage, and fatigue life estimation
5.6.6 Number of cycles above a defined stress level
5.7 Summary
References
6 Internal pressures
6.1 Introduction
6.2 Single windward opening
6.2.1 Dimensional analysis
6.2.2 Response time
6.2.3 Helmholtz resonator model
6.2.4 Sudden windward opening with inertial effects
6.2.5 Effect of roof flexibility
6.2.6 Helmholtz resonance frequencies
6.2.7 Non-dimensional formulation
6.2.8 Reduction factors for large volumes and small opening areas
6.3 Multiple windward and leeward openings
6.3.1 Mean internal pressures
6.3.2 Fluctuating internal pressures
6.4 Nominally sealed buildings
6.5 Modelling of internal pressures
6.6 Summary
References
7 Laboratory simulation of strong winds and wind loads
7.1 Introduction
7.2 Wind-tunnel layouts
7.2.1 Historical
7.2.2 Open-circuit type
7.2.3 Closed-circuit type
7.3 Simulation of the natural wind flow
7.3.1 Similarity criteria and natural growth methods
7.3.2 Methods for short test sections
7.3.3 Simulation of the surface layer
7.3.4 Simulation of tropical cyclone and thunderstorm winds
7.3.5 Laboratory simulation of tornadoes
7.4 Modelling of structures for wind effects
7.4.1 General approach for structural response
7.4.2 Modelling of internal pressures
7.4.3 Simulation requirements for structures in tornadoes
7.4.4 Reynolds Numbers and roughening techniques
7.4.4.1 Example
7.5 Measurement of local pressures
7.5.1 Single-point measurements
7.5.2 Measurement of area-averaged pressures
7.5.3 Equivalent time averaging
7.6 Modelling of overall loads and response of structures
7.6.1 Base-pivotted model testing of tall buildings
7.6.2 The high-frequency base-balance technique
7.6.3 Sectional and taut strip models of bridges
7.6.4 Multi-mode aeroelastic modelling
7.6.5 Simulation requirements for tensioned and pneumatic structures
7.6.6 Aeroelastic modelling of chimneys
7.6.7 Distorted ‘dynamic’ models
7.6.8 Structural loads through pressure measurements
7.7 Blockage effects and corrections
7.8 Computational wind engineering
7.9 Summary
References
8 Low-rise buildings
8.1 Introduction
8.2 Historical
8.2.1 Early wind-tunnel studies
8.2.2 Full-scale studies
8.3 General characteristics of wind loads on low-rise buildings
8.3.1 Pressure coefficients
8.3.2 Dependence of pressure coefficients
8.3.3 Flow patterns and mean pressure distributions
8.3.4 Fluctuating pressures
8.4 Buildings with pitched roofs
8.4.1 Cladding loads
8.4.2 Structural loads and equivalent static load distributions
8.4.3 Hipped roof buildings
8.4.4 Effect of surrounding buildings: shelter and interference
8.5 Multi-span buildings
8.6 Effects of parapets on low-rise buildings
8.7 Effect of building length
8.8 Internal pressures
8.9 A case study: optimum shaping of a low-rise building
8.10 Wind-tunnel databases
8.11 Summary
References
9 Tall buildings
9.1 Introduction
9.2 Historical
9.3 Flow around tall buildings
9.4 Cladding pressures
9.4.1 Pressure coefficients
9.4.2 Pressure distributions on buildings of rectangular cross-section
9.4.3 The nature of fluctuating local pressures and probability distributions
9.4.4 Statistical methods for determination of peak local pressures
9.4.5 Strength characteristics of glass in relation to wind loads
9.5 Overall loading and dynamic response
9.5.1 General response characteristics
9.5.2 Effect of building cross-section
9.5.3 Corner modifications
9.5.4 Prediction of cross-wind response
9.5.5 Database for tall building loading and response
9.6 Combination of along- and cross-wind response
9.7 Torsional loading and response
9.8 Interference effects
9.8.1 Upwind building
9.8.2 Downwind building
9.8.3 Interference effects on local pressures
9.9 Damping
9.9.1 Structural damping
9.9.2 Visco-elastic dampers
9.9.3 Tuned mass dampers
9.9.4 Tuned liquid dampers
9.10 Motion perception and acceleration criteria
9.11 Directionality
9.12 Case studies
9.13 Summary
References
10 Large roofs and sports stadiums
10.1 Introduction
10.2 Wind flow over large roofs
10.3 Arched and domed roofs
10.3.1 Arched roofs
10.3.2 Domed roofs
10.4 Effective static load distributions
10.4.1 Contributions of resonant components
10.5 Air-supported roofs
10.6 Wind-tunnel methods
10.7 Case studies
10.8 Summary
References
11 Towers, chimneys and masts
11.1 Introduction
11.2 Historical
11.2.1 Lattice towers
11.2.2 Tall chimneys
11.3 Basic drag coefficients for tower sections
11.3.1 Drag coefficients for solid cross-sections
11.3.2 Drag coefficients for lattice towers
11.4 Dynamic along-wind response of tall slender towers
11.5 Cross-wind response of tall slender towers
11.5.1 Sinusoidal excitation models
11.5.2 Random excitation model: Vickery–Basu model
11.5.3 Random excitation model: Hansen model
11.5.4 Hybrid model of ESDU
11.5.5 Comparison of predictions of cross-wind response
11.6 Cooling towers
11.7 Guyed masts
11.8 Wind turbine towers
11.9 Case studies
11.10 Summary
References
12 Bridges
12.1 Introduction
12.2 Basic force coefficients for bridges
12.3 The nature of dynamic response of long-span bridges
12.3.1 Vortex-shedding excitation
12.3.2 Flutter instabilities and prediction of flutter speeds
12.3.3 Buffeting of long-span bridges
12.3.4 Effective static load distributions
12.4 Wind-tunnel techniques
12.5 Vibration of bridge cables
12.5.1 Rain–wind vibration
12.5.2 Excitation mechanisms
12.5.3 Solutions
12.6 Case studies
12.7 Summary
References
13 Transmission lines
13.1 Introduction
13.2 Structural response and calculation of wind loads
13.2.1 Nature of the response
13.2.2 Wind forces on conductors
13.2.3 Span reduction factor
13.2.4 Conductor shielding
13.2.5 Wind forces on lattice supporting towers
13.3 Risk models for transmission line systems
13.3.1 Tornado risk model
13.3.2 Downburst risk model
13.4 Wind-induced vibrations of transmission lines
13.4.1 Vortex-induced ‘aeolian’ vibration
13.4.2 ‘Galloping’ vibrations
13.4.3 Wake-induced vibrations of bundled conductors
13.4.4 Turbulent buffeting
13.5 Summary
References
14 Other structures
14.1 Introduction
14.2 Walls and hoardings
14.2.1 Single walls under normal and oblique winds
14.2.2 Walls with corners
14.2.3 Parallel two-dimensional walls
14.2.4 Elevated hoardings
14.2.5 Spanwise averaging
14.3 Free-standing roofs and canopies
14.3.1 Pitched-free roofs
14.3.2 Effect of porosity
14.3.3 Tensioned fabric roofs and shade sails
14.4 Attachments to buildings
14.4.1 Canopies, awnings and parapets
14.4.2 Solar panels on roofs
14.5 Antennas
14.5.1 Radio telescopes
14.5.2 Microwave dish antennas
14.5.3 Rotating radar antennas
14.5.4 Mobile telephone antennas
14.5.5 UHF television antennas
14.6 Lighting frames and luminaires
14.7 Industrial complexes and offshore platforms
14.8 Summary
References
15 Wind-loading codes and standards
15.1 Introduction
15.2 General descriptions
15.2.1 ISO/DIS 4354: Wind Actions on Structures
15.2.2 EN 1991-1-4.6 Eurocode 1. Parts 1–4 wind actions
15.2.3 ASCE Standard ASCE 7-10. Minimum design loads for buildings and other structures
15.2.4 AIJ Recommendations for loads on buildings
15.2.5 Australian/New Zealand Standard AS/NZS 1170.2
15.3 Basic wind speeds or pressures
15.3.1 Averaging times
15.3.2 Basic wind speeds in major codes and standards
15.4 Modification factors on wind velocity
15.5 Building external pressures
15.6 Building internal pressures
15.7 Other shapes and sectional force coefficients
15.8 Dynamic response calculations
15.9 Inter-code comparisons
15.10 General comments and future developments
References
Appendix A: Terminology
Appendix B: List of symbols
Appendix C: Probability distributions relevant to wind engineering
Appendix D: Extreme wind climates – A world survey
Appendix E: Some approximate formulas for structural natural frequencies
Appendix F: Example of application of the LRC method for the effective static wind loads on a simple structure
Index