Ground motion intensity measures for performance-based earthquake engineering

摘要

A critical issue in the probabilistic framework for performance-based earthquake engineering is the choice of ground motion intensity measure(s). In an effort to identify optimum intensity measure(s), a comprehensive parametric statistical study based on 881 earthquake record components was conducted to identify the correlation between (1) seismological variables (SV's) and traditional ground motion intensity measures (IM's), and (2) various nonlinear SDOF response parameters indicative of damage. A set of new nonlinear SDOF-based ground motion intensity measures is defined and proposed to complement the elastic spectral acceleration at the initial fundamental period (T_0) of the structure. The correlation performance of the new intensity measures is compared to that of traditional intensity measures. The new intensity measures are shown to be efficient in reducing the dispersion of nonlinear single-degree-of-freedom (SDOF) response parameters across a wide range of initial periods T_0 and strength levels. A few alternative vectors of optimum ground motion intensity measures are proposed, which consist of the 5 percent damped elastic spectral acceleration at the initial fundamental period of the structure as the primary intensity measure complemented by one or two newly proposed nonlinear SDOF-based ground motion intensity measures as secondary intensity measures.