Structural Implications in Earthquake Design of Tall Buildings in Malaysia

The impacts of the dynamic properties of wind and earthquake on the response of a
newly designed 39-storey reinforced concrete (RC) tall building in Kuala Lumpur,
Malaysia are investigated. Samples of several types of structural members were chosen
in a lower level to represent the steel to concrete ratio (AS/A, ) as a technical-economical
indication of the project. These are two rectangular columns (one at the side 1.000
x2.200 m and another near the middle 1.000 x l. 600 m), a beam near the middle
1.000x0.700 m, and a 350 mm shear wall. The commercial structural analysis software,
ETABS, was applied to simulate the response of the building to a potential local
earthquake. Structural analysis was based on the British Standard BS8110 using
Response Spectrum Analysis (RSA). The response of the building to a range of likely
wind speeds under ultimate load combination was also simulated using the same
software. Representative responses were then monitored: maximum horizontal
displacement at the top corner of the building, AS/ACa, nd peak accelerations. As for the
wind, equating the maximum roof displacement to that of a hypothetical equivalent
cantilever beam, a linear relationship for the equivalent modulus of elasticity of the tall
building, Eeq, is found. It is shown that such parameter could be used for a quick
calculation of maximum roof displacement of various structural systems for tall
buildings. Various plots of the response of the structure to earthquake and wind will
provide for insight into the sensitivity of the design to seismic and wind loading. They
can be used in the conceptual design of the building where quick technical and
economical comparison of numerous alternatives is often necessary. The findings could
disseminate the recent awareness caused by the Sumatra earthquake (December 2004)
among design engineers of high rise buildings