Reliability Analysis Of Corroded Concrete Filled Steel Tubular Component Based On Stochastic Process

Based on the theoretical analysis,systematic research on the bearing capacity of concrete filled steel tubular components decay and the reliability analysis of the components under corrosion environment.The main work is as follows:(1)Through the analysis about the domestic and foreign in the present situation.Combined with Chinese conditions,through MCMC theory,design a method to establish a reliability model for corroded concrete filled steel tubular components.(2)Through collecting and sorting out a large number of references and datas,analyze the causes of corrosion failure of concrete filled steel tubular members,put forward three main corrosion forms of CFST.(3)Han Linhai proposed a calculation formula to calculate the ultimate bearing capacity of circular concrete filled steel tubular under uniform corrosion and long-term load.(4)Based on the twin shear unified strength theory,the Mises yield criterion and the fracture mechanics theory,the formula for calculating the ultimate bearing capacity of concrete filled steel tubes under local corrosion is established.(5)Utilize the formula of ultimate bearing capacity of CFST members under the uniform and local corrosion,supplemented by examples,the axial compression earing capacity decay curve of the non time varying process can be obtained.The influence parameters of the ultimate bearing capacity of concrete filled steel tubular are analyzed.(6)Regard uniform corrosion depth as time varying characteristic of concrete filled steel tubular in uniform corrosion.Based on the parameter estimation method and MCMC method,the uniform corrosion depth prediction model is established.The results show that the MCMC method can be used to predict the corrosion depth of concrete filled steel tubes under uniform corrosion.(7)Regard local corrosion depth and the number of the corrosion pits as time varying characteristic of concrete filled steel tubular in local corrosion.Based on the depth of corrosion pits and the number of corroded active points,the prediction model of the depth and the number of corroded active points of the concrete filled steel tubular members under local corrosion was obtained.Used by the MCMC method and the prediction model,the depth of the deepest pit and the number of the active points of the corrosion are obtained,compared with the actual value,The results show that the MCMC model can simulate the corrosion depth and the number of pits.(8)Base on the uniform corrosion depth,the deepest rust pit depth and the number ofcorrosion,the formula of the ultimate bearing capacity of steel tube concrete component under the time-dependent process in uniform corrosion and local corrosion is established,through the simulation software Matlab software,explore the corrosion of steel tube concrete variable limit bearing capacity decay law.(9)Confirm the uniform corrosion and local corrosion under the steel pipe concrete component reliability evaluation parameters,established the reliability analysis method of CFST with uniform and local corrosion,using Monte Carlo simulation method,obtain the failure probability curve.