在役公铁两用跨海斜拉桥性能评估方法OA

To address the difficulty of cross-validating multi-source data for in-service road-rail sea-crossing cable-stayed bridges,a dual-reference closed-loop evaluation method is proposed.This method utilizes a calibrated Finite Element Model(FEM)as the theoretical baseline,and historical Structural Health Monitoring(SHM)records along with routine inspection results as the temporal base-line.Under a unified relative difference index,a closed-loop evidence chain is constructed,encompass-ing the overall stiffness,dynamic characteristics,and mechanical states of key components.First,static and dynamic vehicle load tests are conducted to obtain the displacement,strain,and influence lines of the main girder,which are then compared with theoretical results.Second,Operational Modal Analysis(OMA)is employed to extract the first eight modal parameters,which are subsequently veri-fied against theoretical values and historical data.Third,vibration acceleration signals from representa-tive stay cables are collected;the cable forces are calculated based on the modified taut-string theory and validated against historical records and FEM-calculated distributions.Finally,preprocessing pro-cedures,including environmental baseline correction,detrending,and band-pass filtering,are applied to mitigate interference from non-structural factors,thereby establishing a verifiable and traceable multi-source closed-loop evaluation process.The results indicate that the relative deviation between the measured static-load displacement at the mid-span and the FEM-calculated value is less than 6.5％,and the dynamic load influence line aligns closely with the theoretical predictions,demonstrat-ing that the bridge's overall stiffness and load transfer characteristics remain stable.The frequencies of the first eight modes are generally consistent with the theoretical and historical baselines,with the rela-tive difference rates for most modes not exceeding 3％,indicating no significant degradation in overall dynamic stiffness.The relative deviation in the forces of representative stay cables is within 6.5％,sug-gesting that the mechanical states of key components are fundamentally stable.This method achieves the multi-dimensional cross-validation of vehicle load tests,operational modal identification,and cable force measurements,providing a reliable reference for routine structural inspections and opera-tion and maintenance decision-making for in-service road-rail sea-crossing cable-stayed bridges.