Study On Evaluation Method Of Redundancy Level Of Concrete Girder Bridge Based On Reliability

With the rapid development of highway and bridge industry,the design method and evaluation theory of bridge structure are also progressing.However,many factors,such as environmental corrosion,increased traffic volume,frequent overloading,super earthquakes,and sailing impacts,are still threatening the safety of bridges.For the operation of the bridge,bridge managers are eager to accurately grasp the actual health status and performance of bridges,to take targeted control measures to ensure the safety and reliability of bridges.The redundancy of the bridge structure refers to the ability of the overall structure to continue to withstand the load after the failure of the critical component.Therefore,in order to ensure the stability and safety of the whole structure of the bridge,more and more attention is paid to the effective use of the concept of redundancy,and the internal relationship between the failure mode and the redundancy of the bridge is analyzed to determine the bridge structure resistance due to the key components Failure to fail with continuity.However,most of the current domestic research on the use of redundancy in the construction area,for the bridge structure is still in its infancy.In this paper,the above problems,from the theoretical derivation,simulation analysis and other aspects of research,the main research as follows:(1)Research on Quantitative Evaluation Index of Redundancy of Concrete Beam Bridge.By analyzing the applicability and limitation of the current system redundancy assessment method,on the basis of stochastic finite element method,an objective and deterministic evaluation index of redundancy level of bridge structure is proposed.(2)Research on target redundancy based on reliability.The reliability method of the bridge system is analyzed,and the reliability index of the bridge system is deduced.Based on the calibration result of the reliability,the minimum acceptable value of the redundant system should be satisfied(3)Based on the design specification of concrete bridge in our country,the method of calculating the redundancy level of beam bridge structural system based on our specification is established.For non-redundant bridges,the concept of redundancy is introduced to enhance component strength and improve the safety of the structure.(4)Through the establishment of finite element model of typical prestressed concrete simply supported T-beam bridge,this paper studies the nonlinear behavior of the bridge from step-by-step loading to failure,and uses the proposed method to evaluate the redundancy level of the bridge system to verify the applicability of the proposed method.This paper presents a method and a process suitable for the evaluation of the redundancy of the structural system of concrete girder bridge in China.The results of the study can provide a reference for the revision of the system factor in the assessment and bearing capacity of the chinese highway bridge.