A pushover methodology based on directed modal combination and energy based displacement for seismic performance evaluation of buildings

After recent catastrophic earthquakes, evaluation of the earthquake safety of existing buildings becomes an important issue. In this research area, many studies are conducted and results obtained from these studies are started to include in earthquake codes.In the present thesis, for considering higher modal effects, a new directed modal combination and energy based pushover analysis method is developed. In this method, total plastic energy consumption of structure is obtained after beginning the inelastic behavior by summing plastic energy consumed at each plastic hinge for each consecutive plastic hinge formation steps. Structural responses for each computation steps are calculated by the special form of square root of the sum of the squares rule, which is developed in this thesis by considering instantaneous modal quantities. Following these calculations, it is aimed to construct structural plastic energy capacity curve for determining earthquake performance of a structure. In the examples, designed reinforced concrete buildings are analyzed by traditional pushover analysis procedures and the proposed procedure and obtained results are compared with the nonlinear time history analysis.