A method of estimating general nonlinear dynamic characteristics of sites

A method of estimating the general nonlinear dynamic characteristics is proposed, i.e., the relation between dynamic shear modulus and shear strain and the relation between damping ratio and shear strain, of an unknown site, in which, a known reference site is introduced, and both the unknown site and the reference site are assumed to have the same bedrock outcrop motion, and strong shock and weak shock records of the two sites are used for the estimation. To verify the method, the general nonlinear dynamic characteristics of two real sites in Tianjin district are estimated, and the surface seismic responses and their response spectra of the unknown site under the excitation of Hollywood wave and Treasure Island wave are calculated. It is shown that the proposed method can accurately estimate the general nonlinear dynamic characteristics of the unknown site, and it can be directly applied to engineering practices.