Dynamic interaction of soil – Structure cluster

Abstract

With the rapid progress of urbanization, more and more structure clusters are being built in major cities and small towns, where the spacing of buildings is becoming smaller and smaller. The cluster effect among buildings in the system of soil and structure cluster interaction (SSCI) emerges during an earthquake. The concept of cluster effect of SSCI is presented in this paper. This work investigates and fully presents the cluster interaction in the context of SSCI using a shaking table test based on the finite element method (FEM). Several cases are studied: a single building and a structure cluster, with various loading conditions, such as the El Centro ground record and Shanghai artificial wave. The Davidenkov foundation model is used as the constitutive soil model, and this model describes the dynamic nonlinearity of soil and is conducted using an ANSYS parameter design language and a restarting command. The numerical simulations of the shaking table test are in good agreement with the experimental records. Extensive analyses on parametric analyses of SSCI are conducted to determine the influence of some parameters of SSCI, including structure spacing, soil property and structure number. Considering the cluster effect under the similar conditions with the experiment, the laws and the influences of soil and structure cluster interaction are fully summarized as follows: the natural frequency of the system of SSCI is less than that of soil and structure interaction (SSI). Under earthquake excitation, the structures in different locations have different responses, and this is the cluster effect of SSCI. Cluster interaction reduces the acceleration responses of structures, while velocity may be larger or less than that of the single building (SSI), and this is related with the earthquake input and the structure location. The displacement of the central building reduces, but these of the surrounding structures along the vibration increase, and the buildings farthest from the center have the largest displacements. The maximum absolute value of the influence coefficients of the cluster effect for displacement reaches 770.94%. The building number is the most significant factor that affects the cluster effect in SSCI system. The cluster interaction constantly reduce when the structure spacing increase and disappears when the clear spacing is larger than 1.32 times as the size of the building foundation, and the cluster effect is weak. Last, the mechanism of SSCI is studied by the laws of the displacement.