Expended Energy Based Seismic Damage Assessment Method for Reinforced Concrete Bare Frames

Abstract

Many past response analyses of the structures under earthquake excitations revealed that newlineboth, the maximum displacements and the number of large-amplitude displacement newlineresponses, cause higher damage to the structures. In the present study, a new newlinemethodology is proposed for seismic damage assessment of a reinforced concrete framed newlinestructure, based on the non-linear energy dissipated by the structure, along the completed newlinedisplacement path. Three methods are proposed to assess the global damage state of the newlinestructure under study, for any deformation in. In the proposed methods, the damage index newlineis expressed, at any instant of deformation, as the ratio of non-linear energy dissipated at newlinean instant to the total non linear energy capacity of the structure. newlineThe energy dissipation capacity of a structure is estimated by a non-linear pushover curve. newlineThe area under the classic pushover curve, which is the plot of base shear versus roof newlinedisplacement, lacks the consistent meaning to represent the work done by external forces. newlineTo calculate the energy, a pushover curve is redefined as a plot of base shear versus newlinedisplacement at C.G of external force profile, and the area under the curve represents the newlineenergy dissipated by the structure, which is equal to the work done by external forces. To newlinecalculate the structure energy dissipation capacity, the pushover curve is considered up to newline4% of drift or 2/3 of its ultimate base shear. newlineAs mentioned earlier, three methods are proposed to calculate the non-linear energy newlinecapacity of a structure and are presented as three types of damage methods. Our results newlineindicate that damage method 3 is more efficient in calculating the global damage state of newlinethe structure, at any deformation. Many damage methods exist in the literature, based on newlinedeformation where strength is not considered in estimating the damage. When a member newlineis in non linear state, as deformation increases the strength caring capacity reduces. In the newlinepresent study, damage methods are proposed on energy capacity of the structure, i