Stochastic seismic load model for push-over analyses

摘要

Nonlinear time history analyses are usually required to build fragility curves for seismic reliability analyses. However, this becomes time consuming for large FE model and a great number of runs required to obtain statistical stable results. Alternatively, the nonlinear response of structures subjected to earthquakes can be sufficiently analysed by pushover analysis. For this purpose a stochastic seismic load model in the frequency domain is required, which is presented in this paper. The first part of the model describes the lateral load pattern while the second part comprises the target displacement. The model enables seismic reliability analysis by pushover analysis, which is more efficient than commonly used time history analysis. Furthermore, a direct relationship between the response spectrum at a site and the expected uncertainties in the seismic loading is given. The application of the model is shown in a case study of a moment resisting steel frame.