Research On Reliability Evaluation Of Concrete Beam Bridge Based On Bayesian Models

With the high-speed growth of the number of bridges in our country,most bridges have been serving for decades or even longer.The reliability of some bridges has reduced due to natural and human factors,and even causing serious safety accidents.Therefore,how to objectively and scientifically evaluate the actual use of bridges,and on this basis,how to allow the distribution of bridge maintenance funds reasonable become one of the issues worthy of attention in bridge maintenance.Among the reliability evaluation methods of the existing bridge,the method of refined assessment based on the reliability theory can more truly reflect the objective usage of bridges.This paper introduces the Bayesian theory to correct the parameter probability distribution of the bridge structure based on this assessment method,and combines the measured data with the correction model,then applies it to the reliability assessment method.At the same time,the response surface method is used to construct the structural limit state equation,then the probability distribution and the limit state equation are combined to evaluate the reliability of the existing bridges,so as to get the actual working condition of the bridges,thus guiding the relevant maintenance departments to allocate maintenance funds reasonably.The research contents of this paper mainly including:(1)Combing and summarizing the reliability research and the evaluation methods of bridges,comparing and analyzing the applicability,advantages and disadvantages of each assessment methods,which reflects the superiority of the evaluation method proposed in this paper.This paper summarizes the overseas and domestic research status of application of Bayesian method in bridge structure assessment,and leads to the necessity of the method proposed in this paper.(2)Through studying and researching on the Bayesian theory and the Bayesian model,this paper corrects the parameter probability distribution of the bridge structure by using the Bayesian Forecasting theory and the existing bridge measurements.The tensile strength of steel bar has a great influence on the ultimate bearing capacity of the existing bridge in the distribution model of bridge resistance effect,so the distribution model of vehicle load effect in the distribution model of bridge load effect and the tensile strength of steel bar have been selected for real-time correction and prediction.(3)Taking an example,the finite element model of the bridge structure is established and calculated by ABAQUS.And then the reliability of the bridge structure is evaluated according to the probability distribution models of the bridge structural parameter modified by Bayesian model and the limitation state equation.The results show that this method is feasible and applicable.