Sensitivity analysis of a seismic risk scenario using sparse Chebyshev polynomial expansion

Abstract

Global parametric sensitivity analysis of a complete seismic risk scenario is performed by means of the response surface method based on sparse Chebyshev polynomial expansion. Hazard model, described via a mixed technique combining Green's function and stochastic methods, is used to simulate free-field seismic records. Vulnerability model, based on the period-dependent damage spectra, is constructed using principles of normalized hysteretic energy and displacement ductility. Approximation of the risk model by means of orthogonal polynomials allows to compute sensitivity indices for model parameters directly from the interpolation matrix. The Monte Carlo method runs on top of the meta-model and allows to build probability density functions of the damage index at target period. The proposed method for sensitivity analysis is useful for understanding the impact of aleatory uncertainties on the risk model outputs.