Assessment of Seismic Structural Damage

Most existing structural seismic damage measures are based either implicitly or explicitly on some measure of the maximum ductility attained or desired, or on peak acceleration. In this paper, two completely new damage measures are described, one based on the concept of equivalent hysteretic cycles of deformation and the second on concepts derived from low‐cycle fatigue theory. When combined, these techniques permit one to evaluate damage based not only on ductility principles, but also on the repetitive cyclic nature of the deformation response. Examples of the applicability of the damage measures are presented herein through comparisons with published experimental data, in which the recorded responses include hysteretic behavior. Two other types of possible applications also are demonstrated; namely, construction of response spectra for representing nonlinear effects, and a tentative new approach to building code drift limits. Other applications are obvious, such as evaluating remaining margins of strength. It is believed that the simplicity of the approaches, when adapted to specific applications, will make them especially attractive in the future for applications in practice as well as for research purposes.