This paper discusses the seismic torsional response of buildings constructed on the ground including the area where the existing piles have been removed. The eccentric ratios of horizontal stiffness of piles are confirmed by assuming some patterns of the pile arrangement and the stiffness reduction. The superstructure is modeled as a uniform shear-beam, whereas the substructure’s horizontal stiffness is modeled as sway springs with eccentricity. Based on the results of eigenvalue analysis and response spectrum analysis, it is shown that the effect of substructure’s stiffness eccentricity on story drifts of superstructure is not so significant.
