Research On Theory And Application Of Double Broken Line Reliability Evaluation Of Bridge Structure Based On Convex Set Model

In the actual operation of bridges,with the continuous attenuation of self-resistance,natural environment factors,increasing traffic volume and the increase of overloaded vehicles,many bridges have certain problems,and some problems may even affect the safe use of bridges.The existing bearing capacity assessment methods mainly include appearance analysis method,load test method,design theory method,and probabilistic reliability assessment method.Therefore,this paper adopts the non-probabilistic reliability method to evaluate the bearing capacity of the real bridge.The research contents are:(1)Study the relevant knowledge of non-probabilistic reliability theory,analyze the relationship between ellipsoid model and convex set model,analyze the meaning of non-probabilistic reliability indicators,and study the calculation methods of existing non-probabilistic reliability indicators;(2)The relevant knowledge of fuzzy reliability theory is discussed in detail,and the types of fuzzy reliability membership functions,the equation expressions and the acquisition methods of membership functions are analyzed.The distribution form of statistical parameters of each uncertain parameter under the calculation method of probability reliability is studied.The calculation formula of probabilistic reliability and non-probabilistic reliability are studied,the relationship between them is studied,and the bridge grades are classified according to the reliability index.On the basis of the non-probabilistic reliability,the calculation method of the non-probabilistic reliability is improved,and the programming software is used to program and analyze the actual engineering cases,and the relationship between the probabilistic reliability indexes to improve the non-probabilistic reliability is obtained.The size of the non-probabilistic reliability index classifies the bridge safety level;(3)The evaluation of the calculation coefficient of the bearing capacity is studied.The statistical parameters of each parameter of bearing capacity are studied,and the mean and variance are obtained.According to the criterion,the interval of each uncertain parameter is obtained,and then the interval of bearing capacity and load effect is obtained.Propose the implementation steps of improving the non-probabilistic reliability assessment method;(4)According to the actual bridge,go out to measure the relevant performance parameters of the bridge,obtain the bridge bearing capacity check coefficient,calculate the bridge bearing capacity according to the relevant design data,and correct the bearing capacity through the check coefficient.The bridge was modeled using Mdas Civil finite element software to extract dead and vehicle load bending moments.The limit state equation is established to solve the non-probabilistic reliability index.