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

摘要

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.