Nonlinear Dynamic Analysis of Structures Under Near-Fault Ground Motions Using an Improved Scaling Method

Assessment of the seismic performance of a structure often requires conducting nonlinear dynamic analyses under a set of ground motion records scaled to a specific level of intensity using an appropriate scaling method. In this study to reduce the variability in the seismic demands, a seismic-intensity scaling index is developed through studying weaknesses and strengths of different scaling methods. Results of the incremental nonlinear dynamic analyses of generic frames with 3, 6, 9, 12 and 15 storey under 40 near-fault ground motions show that using root-mean-square value of pseudo spectral accelerations over effective period range of structures can considerably reduce the scatter in the dynamic responses particularly once higher modes and period elongation effects dominate the response. By using this scaling method, the amount of dispersion is nearly independent of the ductility demand level and the number of stories.