AS-NZS 1170-2 (2011) Structural design actions. Part 2: Wind actions

Australian/New Zealand Standard
Structural design actions
Part 2: Wind actions
Originated in Australia as part of AS CA 1-1933.
Originated in New Zealand as part of NZS 1900:1964.
Previous Australian edition AS 1170.2-1989.
Previous New Zealand edition NZS 4203: 1992.
AS 1170.2-1989 and NZS 4203:1992 jointly revised. amalgamated
and redesignated in part as AS/NZS 1170.2:2002.
Second edition 2011.
This Standard was prepared by the Joint Standards Australia/Standards New Zealand
Committee, BD-006, General Design Requirements and Loading on Structures, to supersede
AS/NZS J J 70.2:2002.
The objective of this Standard is to provide wind actions for use in the design of structures
subject to wind action. [t provides a detailed procedure for the determination of wind
actions on structures, varying from those less sensitive to wind action to those for which
dynamic response must be taken into consideration.
The objectives of this revision are to remove ambiguities, to incorporate recent research and
experiences from recent severe wind events in Australia and New Zealand.
This Standard is Part 2 of the AS/NZS I J 70 series Structural design actionsPage
SECTION I GENERAL
1.1 SC()PE... 6
J.2 APPLICATIC)N... 6
1.3 NORMATIVE REFERENCES... 6
1.4 DETERMINATION OF WIND ACTIONS... 7
1.5 UNITS... 7
1.6 DEFIN ITIONS... 7
1.7 NO'rATION... 7
SECTION 2 CALCULATION OF WIND ACTIONS
2.1 GENERAL... 8
2.2 SITE WIND SPEED... 8
2.3 DESIGN WIND SPEED... 8
2.4 DESIGN WIND PRESSURE AND DISTRIBUTED FORCES... II
2.5 WIND ACTIONS... II
SECTION 3 REGIONAL WIND SPEEDS
3.1 GENERAL... 14
3.2 REGIONAL WIND SPEEDS (VR)... 14
3.3 WIND DIRECTION MULTIPLIER (Md)... 14
3.4 FACTORS FOR REGIONS C AND D (Fe, FD)... 15
SECTION 4 SITE EXPOSURE MULTIPLIERS
4. I GENERAL... 18
4.2 TERRAIN/HEIGHT MULTIPLIER (Mz.ea,)... 18
4.3 SHIELDING MULTIPLIER (M,)... 21
4.4 TOPOGRAPHIC MULTIPLIER (M,)... 22
SECTION 5 AERODYNAMIC SHAPE FACTOR
5.1 GENERAL... 26
5.2 EVALUATION OF AERODYNAMIC SHAPE FACTOR... 29
5.3 INTERNAL PRESSURE FOR ENCLOSED RECTANGULAR BUILDINGS... 29
5.4 EXTERNAL PRESSURES FOR ENCLOSED RECTANGULAR BUILDINGS... 32
5.5 FRICTIONAL DRAG FORCES FOR ENCLOSED BUILDINGS... 40
SECTION 6 DYNAMIC RESPONSE FACTOR
6.1 EVALUATION OF DYNAMIC RESPONSE FACTOR... 42
6.2 ALONG-WIND RESPONSE OF TALL BUILDINGS AND FREESTANDING
TOWERS... 42
6.3 CROSSWIND RESPONSE... 45
6.4 COMBINATION OF ALONG-WIND AND CROSSWIND RESPONSE... 50A DEFIN ITJ()N S... S I
B NOTATION... SS
C ADDITIONAL PRESSURE COEFFICIENTS FOR ENCLOSED BUiLDINGS... 61
D FREEs'rANDING WALLS, HOARDINGS AND CANOPiES... 67
E AERODYNAMIC SHAPE FACrORS FOR EXPOSED STRUCTURAL
MEMBERS, FRAMES AND LATTICE TOWERS... 78
F FLAGS AND CI RClJLAR SHAPES... 91
G ACCELERATIONS FOR WIND SENSITIVE STRUCTURES... 93