Research Of Seismic Vulnerability And Residual Capacity Analysis Of Reinforced Concrete Frame Building By Using Response Surface Method

The failure probability of a structure under various earthquake intensities can be predicted by the method of seismic vulnerability analysis.The status of a structure during aftershocks that damaged by mainshock can be predicted by aftershock carrying capacity.Combination of the said two methods can evaluate the seismic performance of a structure more comprehensively.The method of Incremental Dynamic Analysis(IDA)is an effective tool in seismic vulnerability analysis and residual capacity assessment of a building.However,it usually need too much time during IDA because there are too many cases have to be considered.The calculation efficiency of IDA method is low.The Response Surface Method(RSM)is a powerful mathematical tool,which is usually used to establish nonlinear mapping relationship between various targets,constraints,and design variables.If the RSM is used during IDA,the number of calculation cases of IDA can be reduced significantly and calculation efficiency of IDA will be improved.The way that how to use RSM in IDA and residual capacity assessment is investigated in this study.The main contents in this thesis are as follows:(1)A real building that was damaged during the 2014 Ludian earthquake in Yunnan province(the teaching building of Longquan Middle School in Longtoushan Town)is chosen as the study case.The method that establish response surface model of this building is addressed first.(2)Finit element model of such building is established by using the software of OpenSees.Seismic responses of this building under different earthquakes with various intensities are calculated.Randomness of material strength and earthquake intensity is considered during the calculation.Response surface model describeing the relationship between structural material strength,earthquake intensity and structural seismic responses is built.The seismic fragility curves of this building are obtained by using the response surface model.(3)The second response surface model is built based on the structural seismic responses data of the teaching building of Longquan Middle School.The relationship between material strength,intensity of mainshock and structural damage index after mainshock is described by this model.Then structural damage after mainshock can be predicted.In addition,structural seismic responses of this building after a series of mainshock-aftershock sequences are calculated by using OpenSees.The third response surface model is built to describe the relationship between mainshock intensity,aftershock intensity,and structural seismic responses after aftershock.Finally,the relationship between the damage index of this building after mainshock and residual capacity is established.Then the residual capacity of this building after mainshock can be predicted by the damage index.