A rigid surface boundary element for soil-structure interaction analysis in the direct time domain

Many soil-structure interaction problems involve studies of single or multi ple rigid bodies of arbitrary shape and soil media. The commonly used bound ary element methods implement the equations of the rigid body in a form tha t depends on the particulars of the geometry and requires partitioning and condensation of the associated algebraic system of equations. The present w ork employs the direct time domain B-Spline BEM for 3D elastodynamic analys is and presents an efficient implementation of rigid bodies of arbitrary sh ape in contact with, or embedded in, elastic media. The formulation of a ri gid surface boundary element introduced herein is suitable for direct super position in the BEM system of algebraic equations. Consequently, solutions are computed in a single analysis step, eliminating, thus, the need for par titioning of the system of equations. Computational efficiency is also achi eved due to the extremely sparse form of the associated coefficient matrice s. The proposed element can be used for the modeling of single or multiple rigid bodies of arbitrary shape within the framework of the BEM method. The efficiency and general nature of the proposed element is demonstrated thro ugh applications related to the dynamic analysis of rigid surface and embed ded foundations and their interaction with embedded rigid bodies of arbitra ry shape.