Hysteretic mdof model to quantify damage for rc shear frames subject to earthquakes

Abstract

A hysteretic mechanical formulation is derived to quantify local, modal and overall damage in reinforced concrete (RC) shear frames subject to seismic excitation. Each interstorey is represented by a Clough and Johnston (1966) hysteretic constitutive relation with degrading elastic fraction of the restoring force. The local maximum softening damage indicators are based on the variation of the local stiffness and strength deterioration. The modal damage indicators are calculated from the variation of the eigenfrequencies of the structure. A statistical analysis is performed where a sample 5 storey shear frame is subject to simulated earthquake excitations, which are modelled as a stationary Gaussian stochastic process with Kanai-Tajimi spectrum, multiplied by an envelope function. The relationship between local, modal and overall damage indices are investigated statistically.