The Earthquake Engineering Online Archive

Hybrid modelling of soil-structure interaction

Gupta, Sunil; Lin, Tsung-Wu; Penzien, Joseph

UCB/EERC-80/09, Earthquake Engineering Research Center, University of California, Berkeley, 1980-05, 126 pages (535/G87/1980)

A hybrid model for the analysis of soil-structure interaction is proposed which promises to be superior to the currently available methods of analysis. The modeling is achieved by partitioning the total soil-structure system into a near-field and a far-field with hemispherical interface. The near-field, which consists of the structure to be analyzed and a finite region of soil around it, is modeled by the finite element method. For the semi-infinite far-field, an impedance matrix corresponding to the interface degrees-of-freedom is developed which accounts for the loss of energy due to waves traveling away from the foundation. For torsional vibrations, the far-field impedance matrix can be determined analytically. For general loading conditions, a semi-analytical approach is adopted in which the far-field is modeled through continuous impedance functions placed in the three coordinate directions at the interface. These frequency-dependent impedance functions are determined by using system identification methods such that the resulting hybrid model reproduces the known compliances of a rigid circular plate on an elastic halfspace. Numerical results obtained using these far-field impedances indicate that the proposed model presents a realistic and economic method for the analysis of three-dimensional soil-structure interaction in surface or embedded structures.

Available online: http://nisee.berkeley.edu/documents/EERC/EERC-80-09.pdf (4 MB)