A combined damage index for seismic assessment of non-ductile reinforced concrete structures

Existing seismic damage indices have been formulated and verified almost exclusively on the basis of flexural damage mechanisms. In this paper, a local damage index proposed previously by the authors for assessing existing reinforced concrete (RC) structures is described. According to its formulation, deterioration caused by all deformation mechanisms (flexure, shear, anchorage slip) is treated separately for each mechanism. Moreover, the additive character of damage arising from the three response mechanisms, as well as the increase in degradation rate caused by their interaction, are fully taken into consideration. The proposed local damage index is first calibrated against experimental recordings and then is applied to predict seismic damage response of one RC column and one frame test specimen with substandard detailing. It is concluded that in all cases and independently from the prevailing mode of failure, the new local damage index predicts well the damage pattern of the analysed specimens