Energy-Based Linear Damage Model for High-Intensity Seismic Loading

Abstract

The traditional use of displacement ductility factor for damage assessment of structures under high-intensity earthquake ground motion is inadequate, since it is implicitly assumed that damage occurs only due to maximum deformation and is independent of the number of nonpeak inelastic cycles or the plastic strain energy dissipated by the structure. A more recent approach, however, considers structural damage as a linear combination of the normalized maximum displacement and normalized plastic strain energy. At the ultimate limit state, the plastic strain energy is assumed to decrease linearly with the increase in displacement amplitude. The ultimate limit state is also assumed to be reached by the structure independent of the load path. In the present paper, experimental verification of the energy-based linear damage model is provided by small-scale tests of steel cantilever beams subjected to large inelastic displacement cycles. Test results support the linear assumption between plastic strain energy and imposed displacement, and the assumption of path independence of response to the ultimate limit state.