Study And Application On Safety Factor Assessment Method In Cantilever Construction Stability Of Continuous Girber Bridges Based On Inverse Reliability Theory

Overturning failure of continuous girder bridges under cantilever construction phase,not only leads to the collapse of whole strucuture,but also threatens the life of construction personnel.Thus,it is a significant problom to reasonabley assess the cantilever construction overturning stability of continuous girder bridges.Through the theory analysis of cantilever construction for continuous girder bridges,combining the reliability theory,the safety factor of overturning stability was investigated in this paper.The specific contents are as follows:1.Through inducting and analyzing the existing research on cantilever construction overturning stability of continuous girder bridges,the construcution method and the major problems were discussed.The theory model of cantilever construction overturning stability of continuous girder bridges was determined,which lays the foundation of computation of safety factors of cantilever construction overturning stability;2.Aiming at the difficulty of traditional safety factor method that cannot consider the paramter uncetainties,Combining the deterministic analyzing model of cantilever construction overturning stability of continuous girder bridges and the inverse reliability theory,based-inverse reliability mehthod was proposed to compute the safety factors of cantilever construction overturning stability.The computing procedure can be ahchieved by intergrating the FERUM with MALTLAB software;3.Taking the example of cantilever construction overturning stability of continuous girder bridges as the research object,safety factors of overturning stability of cantilever construction of continuous girder bridges were calculated based on the proposed method,while the sensitivity analysis of concerned parameters was conducted.Through comparing the results of deterministic model and reliability model,it can be concluded that,the deterministic model could overestimate the safety level of overturning stability of cantilever construction of continuous girder bridges.Thus,it is unfovourable to ignore the uncertainties of parameters in cantilever construction of continuous girder bridges.