A highly efficient and accurate stochastic seismic analysis approach for structures under tridirectional nonstationary multiple excitations

•A highly efficient and accurate I-HPDIM algorithm is proposed.•An absolute-response-oriented scheme of PEM is derived.•A scheme in modelling tridirectional non-uniform nonstationary spatial motions is presented.•The proposed stochastic analysis scheme is implemented in general FE platform.•The proposed analysis scheme is demonstrated in bridge seismic pounding analysis.

This paper proposes an improved high precision direct integration method (I-HPDIM) and an absolute-response-oriented scheme of pseudo-excitation method (PEM) for nonstationary stochastic seismic analysis of large structures under tridirectional nonuniformly modulated spatial ground motions. The proposed approaches resolve the bottle-neck problem of conventional HPDIM and significantly improve computational efficiency of both PEM and HPDIM, making the proposed nonstationary stochastic analysis scheme more attractive for engineering purposes. Hence, it has been implemented in general finite element platforms, having powerful and versatile modelling and analysis capabilities, for stochastic seismic analysis of large and complex structures under tridirectional nonstationary spatial seismic motions.