The spatially varying ground motions are simulated based on an empirical coherency loss function and the response spectrum defined in Chinese seismic design code.Calculations of the relative displacement response between two adjacent bridge segments to spatial ground motions with different wave velocities and coherency losses are conducted

which can be used to determine the minimum gap that an expansion joint must have to avoid pounding between bridge segments.Moreover

the influences on maximum relative displacement response between two adjacent bridge segments induced by ground motion spatial variation and structural vibration characteristics are investigated.Numerical results indicate that the effect of ground motion spatial variation on the relative displacement response is significant

especially when the vibration frequencies of two adjacent bridge segments are similar.To reduce the relative displacement and preclude pounding between adjacent structures

the design recommendation of adjusting the adjacent structures to have similar fundamental frequencies is valid only when the effect of ground motion spatial variation can be neglected.