Modelling of earthquake load onto the ‘structure-soil’ system

Abstract

The paper focuses on simulation of dynamic “structure – soil” interaction (the building located in Odessa is taken as an example) and unbounded soil half-space. Principles for new finite elements developed in LIRA-SAPR software are described. These finite elements simulate the interaction between bounded domain of soil and the rest part of the half-space. The LIRA-SAPR software offers a numerical procedure for the formation of equations of motion and, as a partial case, equilibrium equations in problems with infinite domains. This procedure implemented in the form of new finite elements, which made it possible to form hybrid FEM / SBFEM models and solve almost any physically linear and nonlinear dynamic problems in time by the substructure method. The scaled boundary finite-element method governs these elements. To verify the elements, two problems are solved. The first problem considers the bounded soil where the developed boundary finite elements are introduced. The second problem considers the soil of a relatively large size. Boundary conditions do not influence the wave propagation (conditionally may be treated as unbounded half-space) due to dimensions of soil size. Results of numerical experiment indicate that developed finite elements enable the user to generate models that simulate the real service conditions of building structures under dynamic loads.

The analysis of methods of calculation on dynamic loadings used in modern construction is executed. The real object located in the Comintern district of Odessa region is taken as an example. When the earthquake loads are simulated, the authors use real accelerograms that were taken during the earthquake at the construction site of the object. Described technique enables the user to simulate behavior of the structural system of a building based on the finite elements developed and implemented in LIRA-SAPR program; these finite elements simulate vibration damping.