Simplified Method for Analysis of Tall Buildings in an Earthquake

As for the earthquake design and assessment of the high rise structures, dynamic analysis is always required. However, dynamic analyses can be computationally expensive and require expert judgement. This research aims to introduce simplified methods to analyse the displacement and inter-storey drift of multi-storey buildings in regions of low to moderate seismicity. The generalised force method (GFM) is an approach that has been proved to be suitable for low rise buildings. GFM was first introduced by Lam, Lumantarna and Wilson to analyse the seismic effects of low-medium rise buildings. It can give accurate results of estimates of the deflection and internal forces. In the analysis of low rise building, GFM is based on the fundamental mode of vibration and the higher mode effects are not taken into consideration. However, in this research project, the existing GFM method is extended to be used for high rise building, which means that the higher vibration mode effects (including nth vibration modes) of the building is considered. In addition, the torsional effects of high rise buildings are also taken into consideration. This research will verify the accuracy of GFM by making comparison to the results from ETABS simulation. Four different tall buildings with varied heights ranging from 100m to 200m are analysed by both GFM and ETABS. And the results show that the displacement and inter-storey drift estimated by GFM are accurate and reliable