Prediction of spatially distributed seismic demands in structures
In this paper the efficacy of various ground motion intensity measures (IM’s) in the prediction of spatially distributed engineering demand parameters (EDP’s) within a structure is investigated. While the predictive capabilities of various intensity measures in predicting global seismic demands (such as peak interstorey drift over all floors) have been previously investigated, to date the effectiveness of intensity measures at predicting various measures of seismic demand occurring at spatially differing locations in a structure has not been investigated. This has direct implications to building-specific seismic loss estimation, where the seismic demand on different components is dependent on the component location in the structure. Several common intensity measures are investigated in terms of their correlation with the spatially distributed demands in a 10-storey office building, which are measured based on maximum interstorey drift ratios and maximum floor accelerations. It is found that the ability of an IM to ‘efficiently’ predict a specific EDP depends on the similarity between the frequency range of the IM and the vibration frequencies which control the peak value of the EDP. An IM’s ‘predictability’ is found to have a significant effect on the median response demands for ground motions scaled to a specified probability of exceedance using the ground motion hazard curve.