Implementing Etabs in Australian Standards

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1. Automatic Seismic Loads -Static Analysis

For story drifts and to scale the response spectrum cases

AS1170.4 section 6 correspond to 1996 BOCA seismic loads automatic generation in Etabs
Response Modification, R table 6.2.6(a) AS1170.4
Effec. Peaak Accel, Aa table 2.3
Effec. Peak Velocity Av same as above
Site Coefficient S: 1, 1.2, 1.5 and 2 . In case, require S=0.7, you can adjust the value of Av to suit (increase Av by 1.04 for S=1.2.

(to be continued)

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6.2 Automatic Wind Loads
AS1170.2 wind loads can be generated using ASCE 7-98 static wind loads. The model must have rigid diaphragms at all floors.

Windward Coeff, Cp default is 0.8
Leeward Coeff, Cp default is 0.5, adjust according to building d/b ratio.
Exposure Height, select wind exposed range of stories, neglecting any basement levels.
Wind Speed (mph) enter design wind speed in mph. 1 m/s is 2.25 mph. For example for AS1170.2 limit state design wind speed of V1000=46 m/s enter 103.5 (mph).

Exposure Type A, B, C and D correspond to terrain categories 4, 3, 2 and 1.
Importance Factor, Topography Factor Kzt, Directionality Factor Kd default values are 1.0. Refer note below. Gust factor default value 1.05. This was found to give best fit between wind loads from AS1170.2 and ASCE 7-98 codes.

Adjust any of the factors (Kzt, Kd or the Importance factor) to scale the loads up or down so that the total base shear in ETABS equals the AS1170.2 total loads.