Influence of Relative Density and Pile Spacing on the Behavior of Building Frame Resting on Pile Groups - A Numerical Study

Abstract

In the design of pile foundations, stiffness of the frame is neglected and superstructure is analyzed without considering the flexibility of soil mass. This leads to the inaccurate estimation of design forces (shear force and bending moments) and settlements. ANSYS software which is based on finite element method is used to analyze the influence of sand bed relative density of (35 and 70%), and pile spacing (3D and 4D) on the behavior of building frame supported by group of piles (2×2) when it subjected to vertical loads. Differential settlement and rotation are observed in case of the pile supported building frame. In addition to the pile cap rotation, pile head deflection in the horizontal direction is observed which is due to the interaction of super structure with substructure. The bending moment is negative for the dense sand compare to lose sand because of the more restraint of the piles even at the top layers.