Seismic performance of wheat-silo-pile-soil interaction system implemented by a time staggered coupling of FEM and BEM

Abstract

The response of a column-supported wheat silo to earthquake ground motions is complicated by the nonlinear behaviour of the silo-column structure and the interaction of the pile-soil system. A three-dimensional dynamic wheat-silo-pile-soil (WSPS) interaction modelling framework is developed using a novel and highly efficient time staggered coupling of FEM and time-domain BEM (TD-BEM) methods. Based on the time staggered coupling approach, the entire WSPS interaction system is divided into two sub-systems of wheat-silo-pile and soil. The nonlinear behaviours of wheat-silo-pile sub-system are simulated by the FEM, while the TD-BEM excels in accurately modelling seismic wave propagation in the soil sub-system with infinite extension. The key advantage of the presented time staggered coupling method lies in achieving significant computational efficiency by addressing the challenge of different time steps required for the wheat-silo-pile and soil sub-systems. Notably, this time staggered coupling method promotes efficient computation of complex multibody dynamic systems by separately solving the system equations of the FEM and TD-BEM at different time instants. Using the constructed WSPS modelling system, the interaction effects between the wheat-silo sub-system and the foundation under seismic actions are investigated. Furthermore, comparing to traditional dynamic analysis systems for wheat silos, the characteristic responses of WSPS systems in different silo filling states and with different pile sections are examined. Results indicated that there is considerable scope of balancing the stiffness and the selection of pile types in the seismic design of silos in soft soil regions to improve the seismic performance of the WSPS systems.