Study On Seismic Performance Evaluation Method Of The Damaged Reinforced Concrete Frame Structures

In order to assess the safety and reliability of the reinforced concrete frame structures under different earthquake intensity reasonably,based on the Pushover Analysis（PA）,the Residual Capacity（REC）was chosen as the seismic performance index to evaluate the different damaged state structures’Collapse-Resistent（D₀,D₁,D₂,D₃）.Thus,another seismic performance evaluation approach based on the structure collapse mechanism（MEC）is proposed.The main contents and achievements are as follows:（1）The seismic performance evaluation methods based on PA and MEC approach.The reinforcement was calculated by PKPM,and the PA was conducted by PERFORM-3D software to get the indexes,including ductility factorμ_cap,base-shear coefficientα_y,equivalent single degree of freedom system period T_eq and REC,to evaluate the structural seismic performance.When the MEC approach is used to evaluate the seismic performance of structures,the collapse mechanism has to be judged first.Then,through calculating the structure base-shear V_u,yield rotationθ_y,ultimate rotationθ_uand the corresponding seismic performance parameters,the comparision between PA and MEC approach was conducted.The results show the consistency of PA and MEC approach,so the rationality of MEC method is verified.（2）The seismic performance evaluation of different damage state buildings based on PA.The different global damage states（D₁,D₂,D₃）were defined according to the pushover analysis results of the intact structure（D₀）.The plastic hinges of the damaged elements may be a suitable variation of stiffness,strength and deformation capacity.The models for the different damage state structures were constructed by adapting the homologous modification factors of the damaged plastic hinges.Through performing pushover analysis,the seismic performance parameters were calculated.The comparision of the structures in their“intact”and“damaged”states were conducted.It turns out that the different damage state structures show the similiar tendency obviously in stiffness degradation,strength degradation and ductility degradation.（3）The seismic performance evaluation of the different damage state structures based on MEC approach.According to the rules of PA for the different damage state structures in terms of stiffness degradation,strength degradation,ductility degradation,the seismic performance parameters of the different damage state structures based on MEC approach could be directly decreased from the intact structure,and the results were compared with the pushover analysis.The analysis results show that the MEC approach are in good agreement with the pushover analysis results,consequently,the rationality of the MEC approach is verified...