Research On Seismic Collapse Relibility And Sensitivity Of RC Cast-in-place And Prestressed And Subassemblage Frame Structures

The probabilistic seismic performance evaluation based on reliability is one of the main research points of perfo rmance-b ased earthquake engineering and performance-based seismic design.Seismic collapse reliability of structures is a quantitative measure of probabilistic seismic risk of civil infrastructures,and the Pushover analysis method as the core method of performance-based seismic design theory is also applied to the calculation of reliability.Therefore,it is significant to give a further study on the applicability and sensitivity of the relevant parameters in the calculation of structural seismic collapse reliability based on the randomized Pushover method.In this paper,the models of RC cast-in-place and prestressed and subassemblage frame structures were analyzed,and the applicability and sensitivity of the parameters in the calculation of seismic collapse reliability of structures under rare earthquake were studied.The main research contents are as follows:Based on the maximum entropy method and Rosenblueth method,the formulas for calculating the relative sensitivity of the failure probability to the distribution parameters of random variables were derived,and the applicability of the method was verified by different examples.In addition,based on the MATLAB software,the maximum entropy method and Sobol method calculation program were compiled,and some numerical examples were given to verify the feasibility of the method and the correctness of the prograr.Based on the Pushover method and the maximum entropy method,the approach for calculating seismic collapse reliability of structures was established.Then MATLAB software was used to call SAP2000 software,which led to a MATLAB-SAP2000 program for calculating seismic collapse reliability of structures.The program completed the whole progress of calling S AP2000 software and calculating the failure probability of structures by fitting the probability density function of the maximum story drift angel.Then,the probability density function of the maximum story drift angel was fitted by the time history analysis of RC cast-in-place frame structures with a certain amount of seismic waves.The results were compared with those of randomized Pushover analysis and they were used to analyze the applicability of the way of randomizing demand spectrum,the vertical distributions of lateral load and structural behavior types which were used in the progress of calculation of seismic collapse reliability of RC cast-in-place frame structures under rare earthquake.Then a method was proposed to correct the results of randomized Pushover analysis.The Sobol method was inserted into the MATLAB-SAP2000 program,which led to a global sensitivity analysis program for the structural roof displacement.Then the sensitivity analysis of the roof displacement of RC cast-in-place frame structures under different seismic fortification intensity and different storey height was analyzed,and the results were extended to the parameter sensitivity level of seismic collapse reliability of structures.Furthermore,the calculation process of seismic collapse reliability of structures based on deformation was simplified and the applicability of the conclusion was verified by comparing the probability density function of the maximum story drift angel obtained by different methods.The preliminary analysis on the sensitivity of roof displacement of RC prestressed and subassemblage frame structures under rare earthquake to the random variables was carried out with the means of Tornado diagram method.According to results,four variables were chosen,which were the most sensitive.Then the sensitivity of seismic collapse reliability of the structures to the distribution parameters of relative random variables was further analyzed,and the results were compared with those of the cast-in-place frame structures.