عنوان مقاله [English]
Soil-structure interaction is an emerging issue in seismic design of structures. According to the history of the field, this phenomenon is usually studied in two sequential parts, i.e., kinematic and inertial interactions. Kinematic interaction causes the difference of free field motion and foundation input motion in the absence of masses of super structure and its foundation. Filtering the system input motions is the most crucial characteristic of this part of the problem. In the literature on Kinematic interaction, however, most of researchers have focused on single foundation. In addition, few studies can be found on adjacent foundations with semi-cylinder cross- section under plane SH wave. While every building, located in urban area, is commonly surrounded by various structures. It causes the adjacency of foundations inevitable. Hence, it would be important to investigate the ways to include the effects of nearby foundations on input motions. The existence of neighbor foundations may physically be interpreted as constraints in mathematical equations. In this work, the proximity effect of two strip foundations on foundation input motion is investigated. The free field motion is considered as vertical propagating SV waves with just translational movement at the surface. Various embedment depths and different proximity distances between foundations are studied. The simulation is done by ABAQUS software and the analysis is performed in three stages. First, the changes in time history of a sample record through a class
of adjacency conditions were explored. Then, frequency domain aspects of proximity effect were investigated. In the third and final steps, spectral aspects of this phenomenon were examined for the same class of adjacency conditions. The results are presented in non-dimensional format. The main deduction is that for a surface foundation, adjacency to an embedded foundation
causes rocking and vertical input motions. Meanwhile, the translational movement is adjusted too. This adjustment would intensify or diminish the free field translational motion in different frequency ranges.