AS 1170.2-1989

1 - AS 1170.2-1989 SAA LOADING CODE - WIND LOADS (Amdt 3)
4 - PREFACE
5 - CONTENTS
6 - SECTION 1. SCOPE AND APPLICATION
6 - 1.1 SCOPE.
6 - 1.2 APPLICATION.
6 - 1.3 DESIGN PROCEDURES -SIMPLIFIED OR DETAILED.
6 - 1.3.1 Simplified procedure.
6 - 1.3.2 Detailed procedure - static and dynamic analysis.
6 - 1.4 DESIGN REQUIREMENTS.
6 - 1.4.1 General.
6 - 1.4.2 Stability limit state.
6 - 1.4.3 Strength limit state.
6 - 1.4.4 Ultimate limit states.
6 - 1.4.5 Serviceability limit state.
6 - 1.4.6 Permissible stress design procedure.
6 - 1.5 DETERMINATION OF WIND LOADS.
6 - 1.5.1 Methods of determination of wind loads.
7 - 1.5.2 Wind tunnel tests or similar determinations.
7 - 1.5.3 Wind tunnel tests on a specific structure.
7 - 1.6 DEFINITIONS.
8 - 1.7 NOTATION.
11 - SECTION 2. SIMPLIFIED PROCEDURE
11 - 2.1 INTRODUCTION.
11 - 2.2 LIMITATION.
12 - 2.3 PROCEDURE.
12 - 2.3.1 General.
12 - 2.3.2 Forces (F) on elements of buildings.
12 - 2.4 BASIC PRESSURES.
12 - 2.4.1 External pressures on rectangular buildings.
12 - 2.4.1.1 General.
12 - 2.4.1.2 Windward sections of roofs.
12 - 2.4.1.3 Leeward sections of roofs.
12 - 2.4.1.4 Walls and undersides of eaves.
14 - 2.4.1.5 Local negative external pressures.
14 - 2.4.1.6 Local positive external pressures.
14 - 2.4.1.7 Under floor pressures of highset buildings.
14 - 2.4.2 Internal pressures.
14 - 2.4.3 Unenclosed attached canopies, awnings, carports and eaves.
14 - 2.4.3.1 General.
14 - 2.4.3.2 Main structural components.
14 - 2.4.3.3 Roof cladding and its immediate supports.
15 - 2.4.4 Free standing roofs.
15 - 2.4.4.1 General.
15 - 2.4.4.2 Main structural components.
15 - 2.4.4.3 Free roof cladding and its immediate supports.
15 - 2.4.5 Freestanding walls on ground.
15 - 2.4.6 Rectangular hoardings and signs.
15 - 2.5 MULTIPLYING FACTORS.
15 - 2.5.1 Regional multiplying factor (B1).
17 - 2.5.2 Terrain and height multiplying factor (B2).
17 - 2.5.3 Topographic multiplying factor (B3).
17 - 2.5.4 Roof reduction factor (B 4).
19 - 2.6 FATIGUE LOADING.
19 - 2.7 SERVICEABILITY DESIGN LOADS.
19 - 2.8 FARM BUILDINGS AND TEMPORARY STRUCTURES.
19 - 2.8.1 Farm buildings.
19 - 2.8.2 Temporary structures.
20 - SECTION 3. DETAILED PROCEDURE: STATIC ANALYSIS
20 - 3.1 LIMITATION.
20 - 3.2 GUST WIND SPEED.
20 - 3.2.1 General.
20 - 3.2.2 Derivation of design gust wind speed (Vz ).
20 - 3.2.3 Wind direction.
22 - 3.2.4 Terrain category.
22 - 3.2.5 Terrain and structure height multiplier
22 - 3.2.6 Changes in terrain category.
24 - 3.2.7 Shielding multiplier
24 - 3.2.8 Topographic multiplier
24 - 3.2.9 Structure importance multiplier
25 - 3.3 DYNAMIC WIND PRESSURE
25 - 3.4 FORCES (F) AND PRESSURES (p ) ON ENCLOSED BUILDINGS, FREE ROOFS AND WALLS.
25 - 3.4.1 General.
25 - 3.4.1.1 Procedure.
26 - 3.4.1.2. Forces (F) on building elements.
26 - 3.4.1.3 Calculation of forces and moments on complete buildings.
26 - 3.4.2 External pressures
26 - 3.4.3 External pressure coefficients (C ) for rectangular enclosed buildings.
28 - 3.4.4 Area reduction factors (Ka ) for roofs and side walls.
28 - 3.4.5 Local pressure factors (Kl ) for cladding.
30 - 3.4.6 Reduction factors (Kp ) for porous cladding.
30 - 3.4.7 Internal pressures (pi ).
31 - 3.4.8 Frictional drag force (Ff ) for rectangular enclosed buildings.
31 - 3.4.9 Net pressures (pn ) for free roofs.
33 - 3.4.10 Net pressures (p n ) for canopies, awnings and carports, adjacent to enclosed buildings.
33 - 3.4.11 Net pressures (p ) for cantilevered roofs.
34 - 3.4.12 Frictional drag force (Ff) for free roofs and canopies.
34 - 3.4.13 Net pressure (pn) for hoardings and free-standing walls.
35 - 3.5 FORCES ON EXPOSED STRUCTURAL MEMBERS.
35 - 3.5.1 General.
35 - 3.5.2 Procedure.
36 - 3.5.3 Single open frames.
36 - 3.5.4 Multiple open frames.
36 - 3.5.5 Drag force coefficients (C d ) for lattice towers.
37 - 3.6 FATIGUE LOADING.
38 - SECTION 4. DETAILED PROCEDURE: DYNAMIC ANALYSIS
38 - 4.1 APPLICATION.
38 - 4.2 HOURLY MEAN WIND SPEED.
38 - 4.2.1 General.
38 - 4.2.2 Derivation of design hourly mean wind speed (V ).
38 - 4.2.3 Wind direction.
40 - 4.2.4 Terrain category.
40 - 4.2.5 Terrain and structure height multiplier
41 - 4.2.6 Changes in terrain category.
42 - 4.2.7 Shielding multiplier (M s ).
42 - 4.2.8 Topographic multiplier
44 - 4.2.9 Structure importance multiplier (M i ).
44 - 4.3 DYNAMIC WIND PRESSURE
44 - 4.4 PROCEDURE AND DERIVATION.
44 - 4.4.1 General.
44 - 4.4.2 Along-wind response -tall buildings and towers.
46 - 4.4.3 Cross-wind response -tall buildings and enclosed towers.
46 - 4.4.4 Cross-wind response - cantilevered roofs and canopies.
46 - 4.4.5 Cross-wind response - lattice towers and masts.
46 - 4.4.6 Combination of along-wind and cross-wind responses.
50 - APPENDIX A - ADDITIONAL PRESSURE COEFFICIENTS
50 - A1 EXTERNAL PRESSURE COEFFICIENTS (Cp,e ) FOR MULTI-SPAN BUILDINGS (a <60°).
51 - A2 EXTERNAL PRESSURE COEFFICIENTS (Cp,e ) FOR CURVED ROOFS.
52 - A3 EXTERNAL PRESSURE COEFFICIENTS (C p,e ) FOR MANSARD ROOFS.
52 - A4 EXTERNAL PRESSURE COEFFICIENTS (Cp,e ) FORCIRCULAR BINS, SILOS AND TANKS.
55 - APPENDIX B - SECTIONAL DRAG FORCE AND FORCE COEFFICIENTS AND ASPECT RATIO CORRECTION FACTORS
55 - B1 INTRODUCTION.
55 - B2 ROUNDED CYLINDRICAL SHAPES.
57 - B3 SHARP-EDGED PRISMS.
57 - B4 RECTANGULAR PRISMATIC SECTIONS.
58 - B5 STRUCTURAL SECTIONS.
60 - B6 ASPECT RATIO CORRECTIONS.
61 - APPENDIX C - EXPLANATORY MATERIAL TO SECTION 1
61 - C1.1 SCOPE.
61 - C1.2 APPLICATION.
61 - C1.3 DESIGN PROCEDURES - SIMPLIFIED OR DETAILED.
61 - C1.3.1 Simplified procedure.
61 - C1.3.2 Detailed procedure - static and dynamic analysis.
61 - C1.4 DESIGN REQUIREMENTS.
61 - C1.4.1 General.
61 - C1.4.2 Stability limit state.
61 - C1.4.3 Strength limit state.
61 - C1.4.4 Ultimate limit states.
61 - C1.4.5 Serviceability limit state.
61 - C1.4.6 Permissible stress design requirements.
61 - C1.5 DETERMINATION OF WIND LOADS.
61 - C1.5.1 Methods of determination of wind loads.
61 - C1.5.2 Wind tunnel tests or similar determinations.
61 - C1.5.3 Wind tunnel tests on a specific structure.
61 - C1.6 DEFINITIONS.
61 - C1.7 NOTATION.
63 - APPENDIX D - EXPLANATORY MATERIAL TO SECTION 2
63 - D2.1 INTRODUCTION.
63 - D2.2 LIMITATION
63 - D2.3 PROCEDURE
63 - D2.4 BASIC PRESSURES
63 - D2.5 MULTIPLYING FACTORS
63 - D2.5.1 Regional multiplying factor (B1 )
63 - D2.6 FATIGUE LOADING
63 - D2.7 SERVICEABILITY DESIGN LOADS.
64 - APPENDIX E - EXPLANATORY MATERIAL TO SECTION 3
64 - E3.1 LIMITATION.
64 - E3.2 GUST WIND SPEED.
64 - E3.2.1 General.
64 - E3.2.2 Derivation of design gust wind speed (Vz ).
66 - E3.2.3 Wind direction.
68 - E3.2.4 Terrain category.
68 - E3.2.5 Terrain and structure height multiplier
71 - E3.2.6 Changes in terrain category.
73 - E3.2.7 Shielding multiplier (M s ).
74 - E3.2.8 Topographic multiplier
76 - E3.2.9 Structure importance multiplier (Mi ).
76 - E3.3 DYNAMIC WIND PRESSURE (qz ).
76 - E3.4 FORCES (F) AND PRESSURES (pz ) ON ENCLOSED BUILDINGS, FREE ROOFS AND WALLS.
76 - E3.4.1 General.
76 - E3.4.1.1 Procedure.
76 - E3.4.1.2 Forces (F) on building elements.
76 - E3.4.1.3 Calculation of forces and moments on complete buildings.
76 - E3.4.2 External pressures (pe ).
76 - E3.4.3 External pressure coefficients (Cp,e ) for rectangular enclosed buildings.
76 - E3.4.4 Area reduction factors (Ka ) for roofs and side walls.
77 - E3.4.5 Local pressure factors (K l ) for cladding.
77 - E3.4.6 Reduction factors (Kp ) for porous cladding.
77 - E3.4.7 Internal pressures (pi ).
77 - E3.4.8 Frictional drag force (F f ) for rectangular enclosed buildings.
77 - E3.4.9 Net pressures (p n ) for free roofs.
77 - E3.4.10 Net pressures (p n ) for canopies, awnings and carports, adjacent to enclosed buildings.
77 - E3.4.11 Net pressures (pn ) for cantilevered roofs.
77 - E3.4.12 Frictional drag force (Ff ) for free roofs and canopies.
77 - E3.4.13 Net pressures (pn ) for hoardings and free-standing walls.
78 - E3.5 FORCES ON EXPOSED STRUCTURAL MEMBERS.
78 - E3.5.1 General.
78 - E3.5.2 Procedure.
78 - E3.5.3 Single open frames.
78 - E3.5.4 Multiple open frames.
78 - E3.5.5 Drag force coefficients (C d ) for lattice towers.
78 - E3.6 FATIGUE LOADING.
79 - APPENDIX F - EXPLANATORY MATERIAL TO SECTION 4
79 - F4.1 APPLICATION.
79 - F4.2 HOURLY MEAN WIND SPEED.
79 - F4.2.1 General.
79 - F4.2.2 Derivation of design hourly mean wind speed (Vz ).
80 - F4.2.3 Wind direction.
80 - F4.2.4 Terrain category.
80 - F4.2.5 Terrain and structure height multiplier
80 - F4.2.6 Changes in terrain category.
84 - F4.2.7 Shielding multiplier (M s ).
84 - F4.2.9 Structure importance multiplier (M i ).
84 - F4.2.8 Topographic multiplier (M t ).
84 - F4.3 DYNAMIC WIND PRESSURE (q z ).
85 - F4.4 PROCEDURE AND DERIVATION.
85 - F4.4.1 General.
86 - F4.4.2 Along-wind response - tall buildings and towers.
86 - F4.4.3 Cross-wind response - tall buildings and enclosed towers.
88 - F4.4.4 Cross-wind response - cantilevered roofs and canopies.
88 - F4.4.5 Cross-wind response - lattice towers and masts.
88 - F4.4.6 Combination of along-wind and cross-wind responses.
92 - REFERENCES
95 - INDEX

Sets out requirements for establishing the minimum wind loads in structural design, and is in a limit states format. It provides a simplified procedure for the determination of wind loads on a limited range of small structures and buildings, and a detailed procedure on a wide range of structures. Windspeeds are specified for the serviceability and ultimate strength/stability limit states, and for permissible stress design. Explanatory material is given in the appendices.

This Standard sets out procedures for determining design wind speeds and wind loads to be used in structural design of all buildings and components of buildings, bridges (minimum design wind speed only), and other structures subjected to wind. For bridges, the design wind loads shall be determined in accordance with the AUSTROADS Bridge Design Code. Major offshore structures remote from the coast and transmission lines are not covered, nor are the effects of tornadoes which are special-event winds. The design wind loads for structures containing high risk contaminants, such as some nuclear or biological materials is considered outside the scope of this Standard. This Standard does not attempt to account for possible future climatic changes.

Under Revision see DR 99419