Cumulative damage parameters for inelastic systems subjected to earthquake excitations: a comparative study

Abstract

The scope of this study is to evaluate, using three nonlinear, single-degree-of-freedom models (representing both nondeteriorating and deteriorating systems), the inelastic response characteristics which permit the assessment of fatigue damage due to seismic excitation. The systems, with a period of 1 s, are subjected to 69 recorded ground motions of different magnitudes, durations and hypocentral distances. The response parameters are the ductility index (defined as the maximum response normalized to yield displacement) and the energy index (defined as the cumulative hysteretic energy). Based on the rain-flow cycle counting method, the relationships between the response parameters and the cumulative damage are established. Emprical prediction models for cumulative damage are also developed.