A random vibration study of structures under multi-component seismic excitations is presented in this paper. The pseudo excitation method proposed by J. H. Lin is employed and is further developed, from which a multi-component pseudo excitation method is formulated. Then, the random model and correlation for multiple ground motions are investigated. Based on the method, a computer program is developed and a random vibration study is performed for a double-layer spherical lattice shell to investigate its seismic performance under multi-component seismic excitations. It is found that a significant difference may occur between single and multi-component seismic excitations. The present study has shown that the developed method is a highly efficient and accurate CQC algorithm, in which all the cross-correlation terms between both participant modes and seismic excitations are involved. This method can easily be used for multi-component seismic analysis of structures that have closely spaced natural frequencies and coupled vibration modes.

Reinforced concrete shear walls play an important role in improving seismic performance of building structures. In this paper, a new type of RC shear wall with concealed bracing is proposed and investigated. Four 1:3 scale medium-height specimens were designed and a detailed experimental investigation carried out. The load-carrying capacity, stiffness, ductility, hysteretic behavior and energy dissipation of the shear wall are discussed. The failure mechanism was revealed by the experiments. It is found that in comparison with a normal shear wall, the seismic performance of a shear wall can be significantly improved by adding concealed bracing within the wall panel. Finally, a mechanical model of the shear wall is proposed and formulae for calculating load-carrying capacity developed. It is shown that the theoretical results agree well with those from experiments.

Lattice shell is a type of spatial structure whose vibrations are dominated by both horizontal and vertical motion. In this paper, a multidimensional pseudo excitation method is developed for nonstationary random seismic analysis of structures under multi-support and multi-dimensional earthquake excitations, in which the phase lags between the excitations have been involved. Mathematical formulations are derived. A method of evaluating peak responses is recommended. Multi-dimensional seismic random models are discussed. A random vibration analysis is performed for a double-layer cylindrical lattice shell to investigate its seismic performance. It is shown that the developed method is a highly efficient algorithm, which can easily solve the nonstationary problem of large structures under multi-support and multidimensional earthquake excitations.