Contents Volume 1 Preface.- ..- iii List of Figures.- ..- xi List of Tables ..- .. xvii 1. Technical and Historical Overview of Wind Codes..- ..! 1.1 Introduction- ! 1.2 Overview of ASCE 7, IBC, and IRC Wind Loading Methodologies 1 1.2.1 The ASCE Standard No. 7 - 1998 and 2002 Editions! 1.2.2 The 2000 and 2003 IBC- .2 1.2.3The 2000 and 2003 IRC- .3 1.3 Origin of the International Building Code ..- ..3 1.4 History of Wind Provisions in Earlier Model Codes4 1.4.1 Uniform Building Code ..- ..4 1.4.2 The Standard Building Code- ..10 1.4.3 The BOCA National Code- .13 1.5 Wind Provisions in ANSI A58.1 and ASCE 7 Standards15 1.5.1 Early History of the Loading Standard .15 1.5.2ASCE Paper: Wind Forces on Structures- ..16 1.5.3ANSI A58.1-1972- . 17 1.5.4 ANSI A58.1-1982- .18 1.5.5 MBMA Metal Building System Manual Design Procedure ..19 1.5.6 1988 ASCE Standard No. 7 ..- 19 1.5.7 1993, 1995 and 1998 ASCE 7..- ..20 2. Quality Assurance- 23 2.1Relevant 2000/2003 IBC Sections ..- ..23 2.2 Quality Assurance Plans to Provide for Designed-In Wind Resistance 24 2.3 Structural Observation ..- ..25 2.4 The Quality Assurance Plan- 25 3. General Overview of Requirements: IBC, IRC, and ASCE 7 27 3.1Selected and Relevant 2003 IBC Sections- 27 3.2 Discussion of the IBC Provisions ..- 27 3.2.1 IBC Design Basis..- ..27 3.2.2 IBC Wind Design Methods in General .28 3.2.3 General Details of Alternatives- .. 29 3.2.4 Other Supplementary Standards- ..32 3.2.5 Design Criteria and Factors.- ..32 3.3 International Residential Code (IRC)..- 33 3.4 Selected and Relevant ASCE 7-98 Sections (ASCE 7-02 Similar) 33 3.5 Discussion of the ASCE 7 Design Criteria ..- 34 3.5.1 Details of the Methods and Options.- 34 3.6 Flood Loading and Wind Actions.- .38 3.7 Load Precision and Engineering Judgment- ..38 4. Basic Wind Speed..- .. 39 4.12000/2003 IBC and ASCE 7 1998/2002 Sections- .. 39 4.1.1 Selected Relevant IBC Sections ..- .. 39 4.1.2 Selected and Relevant ASCE 7 Sections- .. 39 4.2 Ways of Measuring Wind- . 39 4.2.1 Introduction- .. 39 4.2.2 Three-Second-Gust Wind Speed ..- .. 40 4.2.3 Selection of Wind Speed ..- 40 4.3 The Wind Speed Map- . 43 4.4 Special Wind Regions ..- .. 45 5. Importance Factors ..- 49 5.1Reprinted 2000/2003 IBC and 1998/2000 ASCE 7 Sections 49 5.1.1 Selected and Relevant IBC Sections- 49 5.1.2 Selected and Relevant ASCE 7-98 and 7-02 Sections.. 49 5.2 Importance Factors and Occupancy Categories- .. 50 5.3 Occupancy Categories- .. 50 5.4 Details of these Categories ..- 52 5.4.1 Essential Uses- . 52 5.4.2 Special Uses- 52 5.4.3 Hazardous Uses ..- 53 5.4.4 Miscellaneous Uses ..- ..54 5.4.5 Standard Uses- . 55 5.5 Difficulties with Mixed Uses, or Additions or Alterations.. 55 5.6 Quality Assurance- .. 56 6. Exposure and Topographic Effects.- .. 57 6.1Relevant IBC and ASCE 7 Sections- .. 57 6.1.1 Selected and Relevant IBC Sections- 57 6.1.2 Selected and Relevant ASCE 7-02 Section 6.5.6.1. 57 6.2 Exposure Effects.- .. 58 6.2.1 General Definitions- 58 6.2.2 Discussion of Exposures- 58 6.2.3 Practical Determination of Site Exposure- .. 60 6.3 Velocity Gradient and the Power Law- 60 6.4 Terrain Effects.- . 62 6.4.1 General.- 62 6.4.2 Practical Tips for Determining Hand Lh.. 64 7. Gust Response ..- .. 73 7.1Relevant ASCE 7-02 Sections- 73 7.2 Background Discussion of Flexible and Rigid Structures 73 7.3 Conditions Affecting the Gust Effect Factor..- .. 75 7.3.1 Gust Effect Factor versus Wind Speed and Turbulence 75 7.3.2 Gust Effect versus Size of Structure- . 75 7.3.3 Gust Effect versus Damping of Structure- .. 75 7.4 The True Gust Effect Factor ..- .. 76 7.5 Gust Effect Factor in the ASCE 7 Standard ..- .. 78 7.6 Further Considerations ..- . 78 8. Design of Wind Pressures on Main Wind-Force-Resisting Systems. 81 8.1Selected and Relevant 2000 IBC Sections (2003 IBC is Similar).. 81 8.2 Selected Relevant 1998 ASCE 7 Sections (ASCE 7-02 is Similar) 81 8.3 General.- 82 8.3.1 Mean Roof Height..- . 82 8.3.2 Windward and Leeward Pressures- 85 8.3.3 Internal Pressures- .85 8.4 Complete Load Path- 86 8.5 Directionality Factor..- .87 8.6 Load Combinations and Stress Increases- ..87 8.6.1 LoadCombinations.- 87 8.6.2 Stress Increases ..- 88 8.7 Overview of the Wind Design Methods.- ..89 8.7.1 Comments on the Analytic Method ..- ..89 8.7.2 Comments on Simplified Methods.- ..94 8.7.3 Comments on Torsional Wind Loads ..- 95 8.8 Stability- 103 9. Wind Pressures on Components and Cladding of Structures 105 9.12000/2003 IBC and 1998/2002 ASCE 7 Provisions1- 05 9.1.1 Selected and Relevant IBC Sections- ..105 9.1.2 Selected and Relevant ASCE 7 Sections .105 9.2 Design of Components and Cladding ..- .106 9.2.1 General.- .. 106 9.2.2 Areas of Discontinuities ..- 108 9.2.3 Effective Wind Areas..- .. 110 9.3 Pressures on Structural Elements- . 110 9.4 Determining Code Pressure Values..- .Ill 9.4.1 2003 IBC Methods (2000 IBC Similar) ..111 9.4.2 ASCE Methods ..- Ill 9.5 Practical Design Tips ..- ..111 9.6 Internal Pressure Effects ..- 112 9.6.1 Openings ..- ..114 9.7 Other IBC-Regulated Components and Cladding- .115 10.Glass and Glazing ..- 117 10.1 Relevant 2000 and 2003 IBC Sections- ..117 10.2 Introduction- 118 10.3 General Requirements for Glass and Glazing.- .118 10.3.1 Summary.- 118 10.3.2 Deflection Limits, General.- .. 120 10.4 Specific Wind Design Provisions for Glass and Glazing 120 10.5 Other Glazing Materials- .. 121 10.6 Provisions for Glazing in Hurricane-Prone Regions in Both the IBC and ASCE 7 .. 121 10.7 Practical Examples Demonstrating Glazing Wind Pressure Design or Analysis.. 122 11.Prescriptive Provisions in the IBC, IRC, and Other Referenced Standards 125 11.1 Selected Relevant IBC Sections- .. 125 11.2 Selected Relevant IRC Sections- .. 126 11.3 Code Basis for Conventional Construction- 128 11.3.1 Introduction- . 128 11.3.2 2000 IBC Provisions- 130 11.3.3 IRC Provisions- 133 11.4 Referenced Prescriptive Standards: Comparison and Contrast 134 11.4.1 WFCM and SBCCI SSTD-10 Prescriptive Methods..134 11.5 Comparisons of All Four Methods.- .. 134 11.5.1 General.- .. 134 11.5.2 Detailing Criteria- 135 11.6 International Building Code (IBC) Prescriptive Methods.. 137 11.6.1 Overview of IBC Section 2308 Provisions- 137 11.7 General Pitfalls ..- . 140 11.7.1 Load Path- .140 11.7.2 Topography Effect..- 140 11.7.3 Helpful Tip ..- 140 11.7.4 Wind vs. Seismic in Light-Framed Building Design.. 141 11.7.5 Deflection Considerations ..- 143 11.7.6 Narrow Shear Walls or Braced Panels..- .. 143 11.7.7 Gypsum Board Shear Wall and Braced Panels. 145 11.8 Advice on Using the Four Methods.- . 146 11.8.1 General Loading and Layout..- .. 146 11.8.2 Gable Bracing.- .. 147 11.8.3 Roof Uplift on Rafters.- .. 147 11.8.4 Lack of Hold-Downs in the IBC and IRC Methods.. 149 11.9 Advice on Using WFCM Standard- .. 149 11.9.1 Width Limit..- .. 149 11.9.2 Hold-Downs ..- .. 149 11.10Advice on Using the SSTD 10 Standard ..- . 150 11.10.1 Wind Pressures- ..150 11.10.2 Seismic.- .. 150 11.10.3 Hybrid IRC-WFCM Method..- .. 150 11.11Nailing Comparison- 150 11.12Example Problem 11-1: Use of Prescriptive Requirements for a Conventional Wood-Frame Building ..- . 153 12.Miscellaneous and Non-Building Structures- .. 165 12.1 2000 and 2003 IBC, and 1998 and 2002 ASCE 7 Provisions. 165 12.1.1 Selected Relevant IBC Code Sections- 165 12.1.2 Selected Relevant ASCE 7-98 and ASCE 7-02 Sections 166 12.2 Membrane Structures- .. 166 12.2.1 General.- .. 166 12.2.2 Engineering Design Criteria in ASCE 7.. 166 12.2.3 Temporary Structures- 166 12.2.4 Awnings, Canopies and Parapets- .. 167 12.3 Design of Patio Covers..- 167 12.4 Details for Other Structures- .. 167 12.5 Radio and Television Towers..- 168 12.5.1 General.- .. 168 12.5.2 ASCE Procedure- 169 12.6 Practical Tips on Design of Towers or Tower-Like Structures 170 13.Unusual Wind Loading Conditions- .. 171 13.1 Introduction- .. 171 13.2 Mean Roof Height..- .. 171 13.3 Proximity of Wake Effects.- 172 13.4 Wake Effects at Courtyards- .. 172 13.5 Roof Overhangs and Canopies ..- . 173 13.6 Balconies- 174 13.7 Partially Enclosed Parking Garages.- . 174 13.8 Structures near Stepped Terrain.- .. 175 13.8.1 1998 ASCE 7 Procedure- .. 175 13.8.2 Design Based on a Structure's Life Span 177 13.9 Overturning and Uplift Effects.- .. 177 13.10Topographic Effects ..- .. 179 13.11Determining Site Exposures- 180 13.12Pressures on Partitions in Partially Enclosed Structures 181 13.13 Pressures on Columns in an Open Parking Garage181 13.14 Pressures on Parapets- 181 13.15 Pressures on End Walls of Rigid Frame Structures 182 13.16 Flexible Buildings- . 182 14.High Winds, Hurricanes and Tornadoes ..- 183 14.1 Introduction- 183 14.2 Hurricanes, Cyclones and Typhoons- . 183 14.2.1 General Description ..- 183 14.2.2 Storm Surge..- 185 14.3 Tornadoes- 186 14.3.1 General Description ..- 186 14.3.2 Tornado Classification by the Fujita Scale 189 14.4 Illustrations of Typical Wind-Related Failures- 189 15.Serviceability: A Case for Drift Control.- .197 15.1 Introduction- 197 15.2 2000 and 2003 IBC; 1998 and 2002 ASCE 7 Sections..197 15.2.1 Selected Relevant 2000 and 2003 IBC Sections197 15.2.2 Selected and Relevant ASCE 7-98 and ASCE 7-02 Sections 198 15.3 General.- 198 15.4 Building Drift..- 198 15.5 Occupant Comfort.- 198 15.6 Structural Stability- 199 15.7 Code Drift Limits..- 199 15.8 Summary and Recommendations..-