Influence of BNWF Soil Modelling on Dynamic Behaviour of Pile Foundation for RC Frame with Structural Wall

Abstract

Multistoried Reinforced Concrete (RC) wall-frame buildings are nowadays frequently constructed in severe seismic zones due to their large lateral stiffness and lateral strength. Conventionally, the effect of soil–structure interaction (SSI) on the dynamic behaviour of a wall-frame structure is not considered in its seismic design. As a result, the considered system is stiffer as compared to the actual condition in which the pile-soil system imparts more flexibility and can induce nonlinear behaviour of piles through large deformations. Therefore, it becomes imperative to study the nonlinear behaviour of a wall-frame-pile-soil system. In this study, two different soil domains are created for the influence of soil–structure interaction on the response of the pile foundation, namely (i) the first model incorporating soil–pile interaction effect and (ii) the second model without considering the interaction effect. The response from two different soil domains is applied on a two-dimensional RC wall-frame. The soil-pile system for the RC building frame is modelled as Beam on a Nonlinear Winkler Foundation (BNWF). It is observed that after the application of ground motion, a significant bending moment is generated near the bottom of the pile and nonlinearity extends beyond 50% of the pile length. The observations suggest the necessity for further assessment of the state of the practice for simulating seismic soil–pile interaction.