Response Combination of Tall Unsymmetrical Structures to the Multi-Dimensional Seismic Action

The general vibration mode superposition p ro cedure of the eccentric structure under the multi-dimensional seismic action was set up firstly in the paper. The combination of different seismic components an d modes was discussed. And then, the SRSS method for Response Combination of di fferent seismic components was put forward. The time history analysis of tall un symmetrical structures under the single-dimensional or multi-dimensional compone nts of ground motion was performed. Based on these numerical computation, it can reveal the increment of internal force under multi-dimensional components of se ismic action compared with single- dimensional component. The ratios of the resp onse under two-dimensional seismic action to the combination of responses under each single-dimensional motion through SRSS method were counted. Based on the st atistical results, the SRSS method can be revised by some coefficient. Thus the response spectrum method can be used for the seismic analysis of two-dimensional ground motion.