Dynamic response of adjacent structures under spatially variable seismic waves

In this paper the dynamic response of a system of two structures placed adjacent to each other is studied. The force on the system consists of earthquake loading applying for its spatial variability over short distances. The spatially variable ground motion is defined and explored by two different approaches. First, the deterministic approach accounting only for effects of wave passage of surface waves and inclined body waves, and second, the stochastic (random) approach considering also degree of coherency between motions at every two points of the ground surface as a factor. Effects of the ground motions identified as above on the response of the system are examined assuming a harmonic excitation and considering type of the wave and angle of incidence of the body waves. It is shown that resonance frequency increases with closeness of structures. Moreover, for some cases depending on the distance between the adjacent structures, the structural response increases. The random approach gives more satisfactory results in this comparison study.