عنوان مقاله [English]
In this paper, most influential parameters on nonlinear response of structure-soil-structure system, including time period of main (T1) and adjacent (T2) structure, distance between structures (d) and soil type, have been thoroughly investigated. The purpose of this paper is to understand the effect of changing each parameter on the nonlinear deflection of structures and predicting structural behaviour without modelling the adjacent structure. For this aim, six structures of 2 to 15 stories based on two clay samples is modelled with zero, 10 and 25 meters distance and is analyzed using nonlinear time history analysis. Direct method is used for modelling the systems. According to the results, soft base is caused sharp increase in the ratio of the first story drift to the fix-base with a minimum ratio of 1.1 and a maximum of 3.61. The increase of T1 and T2 is led to increase structural deformation so that T1 effects are at least twice T2. For main structures with T1 in the range of 0.7 to 1.5 times the soil period, Structural drift is intensified; but for main structural time period T1 less than 0.7 times the soil period, the effects of structure-soil-structure interaction are negligible. Base on this study, Contrary to the expectation that increasing the distance between structures leads to a reduction in the effects of structural-soil-structure interaction, only for structures with time period more than 3 seconds, increase the distance between structures, is decreased adjacent structures effects. By comparing drift ratio of structure-soil-structure and soil-structure systems, in one third of the upper elevation of the structure, this ratio has a sudden drop that is compensated in the roof, which with decreasing T2 and increasing d, the accumulation of the drift ratio from the roof to the first floor is transferred. Ultimately, what codes are considered for soft support enforcement is unreliable.