Influence of spatial variability of ground motion on seismic response of bridges

An approach to seismic analysis of bridges under spatially variable ground motions is presented. The phenomenon of spatial variability of earthquakes, its effects on bridge response, and differences with respect to simultaneous excitation of supports, are explained. The model of such excitation is described in detail, and procedures for generation of spatially variable ground motions are outlined. Numerical analysis methods, efficient for solving this problem, are also presented. The described methodology is applied in the seismic analysis of an arch bridge. The analysis results show that the spatial variability of ground motions has a detrimental effect on most of the analysed bridge response values.