Study On State Evaluation Technology Of Long-span Continuous Beam Arch Bridge In High-speed Railway

Continuous beam arch bridge has been developed rapidly in recent years because of its unique mechanical properties and technical advantages.In order to better play the role of the large-span continuous beam arch bridge in transportation and ensure the safety of operation,it is necessary to evaluate the safety status for this kind of bridge in the service.Taking a large-span continuous beam arch bridge of a high-speed railway as the research object,based on the modification of the finite element model of the response surface method,the security early warning system and the state assessment method are studied in this thesis.The main contents are as follows:(1)Based on the static and dynamic response of the bridge,a finite element model correction method of response surface was proposed,which combines the suspension force with the modal frequency of the bridge.The effectiveness of the method was verified by numerical simulation.The results show that the modified parameters have clear physical significance,the modified results are more consistent with the target values,and the modified results are good.(2)On the basis of the finite element model correction,a deterministic early warning method was used to establish a model safety early warning system combining structural static and dynamic characteristics indicators,and the high-speed railway large-span continuous beam arch bridge was foretasted.(3)A multilevel evaluation model system based on static and dynamic indexes,combined with uncertain analytic hierarchy process,was used to evaluate the bridge state.The modified continuous beam arch bridge was taken as a numerical example to verify the feasibility of this method.The results show that the multilevel evaluation system established by this method can effectively evaluate continuous beam arch bridges and be applied to practical projects.