Influence of Size and Load-Bearing Mechanism of Piles on Seismic Performance of Buildings Considering Soil–Pile–Structure Interaction

Abstract

Pile foundations are usually used to transmit foundation loads through soil strata of low bearing capacity to deeper soil or rock strata with a higher bearing capacity and stiffness. The type and size of a pile foundation that supports midrise buildings in high-risk seismic zones can alter the dynamic characteristics of the soil–pile–foundation system during an earthquake due to soil–structure interaction. To investigate these phenomena, a 15-story moment-resisting frame sitting on differently sized end-bearing and floating pile foundations was simulated numerically. The present paper describes a numerical modeling technique for the simulation of complex seismic soil–pile–structure interaction phenomena. By adopting a method of direct calculation, the numerical model can perform a fully nonlinear time history dynamic analysis to realistically simulate the dynamic behavior of soil, pile foundations, and structure under seismic excitations. This three-dimensional (3D) numerical model accounts for the nonlinear behavior of the soil medium, the piles, and the structural elements. Results show that the type and size of the pile elements influence the dynamic characteristics and seismic response of the building due to interaction between the soil, pile foundations, and the structure. The findings of this study can help engineers select the correct size and type of pile foundation while considering the seismic performance of buildings sitting on soft soil and aim at optimizing their design.