Research On Life-Circle Safety Evaluation Method Of Long-Span Concrete-Filled Steel Tube Arch Bridge

Concrete-filled steel tube(CFST)arch Bridges have occupied a leading position in China both in the number of construction and the length of span in just 30 years since it came into China in the 1990 s.However,while various types of Bridges have made breakthroughs in design technology,the corresponding evaluation theory research lags behind.Based on a bridge maintenance and reinforcement project,this paper carried out a study on life-circle safety assessment method of a long span CFST arch bridge,mainly including construction stage and service stage.This paper first summarizes the relevant studies on safety assessment of scholars,analyzes the advantages and disadvantages of various methods,and puts forward the methodology of safety assessment of long-span CFST arch bridge based on the idea of life-circle.The reliable response surface model of target correction quantity and correction parameter is established by means of anova.The objective function of residual error is constructed by genetic algorithm to optimize and modify the value of parameters,so that the model can better reflect the real load effect of the structure.Secondly,the modified meta-model is used to analyze the construction stage,and the actual construction plan is proved by mechanical properties.The reliability of the finite element model was been confirmed by the data of the construction stage,and the stress distribution and stability of the arch rib of the bridge were calculated.The suspension rod force of the bridge was optimized and adjusted by using the influence matrix.The safety of construction were evaluated from two aspects of strength and stability.In the end,the research on material property degradation by domestic and foreign scholars is summarized,and the resistance attenuation model of CFST arch bridge components is established,and the resistance model of the bridge is modified in real time.Considering the components and life-circle the safety evaluation index based on the norm is established to complete the safety evaluation and bearing capacity prediction of components.In this paper,the whole life nonlinear analysis of the large finite element model is been carried out to calculate the ultimate bearing capacity of the structure.The robustness index is used to evaluate the overall safety performance of the structure under the condition of local component failure.In this paper,the safety evaluation method and index system of long-span CFST arch bridge considering the life-circle was been put forward,which would provide reference value for the future evaluation of long-span arch bridge.