Hybrid Modelling of Soil-Structure Interaction: Fid-Bau Portal

Hybrid Modelling of Soil-Structure Interaction

S. Gupta / T. W. Lin / J. Penzien / C. S. Yeh

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 modelling 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 modelled by the finite element method. For the semi-infinite far-field, 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.