The Earthquake Engineering Online Archive

A substructure method for earthquake analysis of structure-soil interaction

Gutierrez, Jorge A.; Chopra, Anil K.

UCB/EERC-76/09, Earthquake Engineering Research Center, University of California, Berkeley, 1976-04, 150 pages (535/G873/1976)

A general substructure method for analysis of response of structures to earthquake ground motion including the effects of structure-soil interaction is presented. Flexibility of the structural base, spatial variations in the free field ground motion, structural embedment and interaction between two or more structures, all these factors are included in the analysis. The soil region may be idealized either as a homogeneous halfspace or as an assemblage of finite elements. In the latter case, results are shown to be equivalent with a direct finite element analysis. However, it is shown that the substructure method is more efficient. The structure-soil system is considered to be composed of two substructures, the structure and the soil region, and the analysis via the frequency domain is carried out in two stages. Several methods to determine the dynamic stiffness matrix for soil regions idealized as an assemblage of finite elements are described. For situations where the soil can be better represented as a laterally unbounded, horizontally layered region, an efficient method which utilizes symmetry and antisymmetry considerations is presented. Application of the substructure method to analysis of dynamic response of two or more nearby structures, in which case the response of one structure may influence the response of others through interaction with the soil, is also presented. The general substructure method is evaluated for efficiency and effectiveness.

Available online: http://nisee.berkeley.edu/documents/EERC/EERC-76-09.pdf (4 MB)