###### Abstract
Finally, it was concluded that there would be a sizable dynamic amplification factor in the middle of the side span and in the middle of the secondary side span and midspan and that the simple support structure at one end of the side span had a greater influence on this factor. [PERSON] et al. [7] took a three-span continuous beam bridge with a variable cross-section as a research object to carry out variable parameter analysis and studied the effect of jump-off on the vehicle-bridge coupling response. In addition, [PERSON] et al. [8] further studied the coupling response of continuous rigid-frame bridges under the action of random traffic flow, fitted the critical dynamic deflection, and then provided the reliability index of the bridge under the corresponding working conditions. [PERSON] et al. [9] studied the impact coefficient of a high-speed railway continuous rigid-frame-arch-combined bridge and obtained the fitting formula of the impact coefficient for each component. [PERSON] et al. [10] established an analytical framework for the wind-vehicle-bridge interaction and analyzed driving comfort based on 2-D road roughness. [PERSON] et al. [11] proposed a simplified analysis method of vehicle-bridge coupling and proved that it can significantly reduce computational costs. [PERSON] et al. [12] proposed a new method of reordering finite element model numbers using the improved Gibbs-Poole-Stockmeyer algorithm and pointed out that the method could significantly improve the iterative calculation of vehicle-bridge coupling efficiency. [PERSON] et al. [13] combined the mass change method with the OMA method to obtain the modal scaling factors for the mass normalization of mode shapes. The effects of vehicle-bridge coupling effect are considered in the study, and the cases that need to be considered and can be ignored are distinguished. [PERSON] et al. [14] used STRIDEX algorithm to process the mobile sensor data and identify the modal characteristics of the bridge under different road roughness level. [PERSON] et al. [15] established a 2-D vehicle model and 3-D vehicle model, and the effects of the different models on the coupling vibration of the vehicle-axle are analyzed. [PERSON] et al. [16] carried out a parameterization study on the uncoupled vehicle-bridge interaction and calculated the influence of different factors on the algorithm error. Through the above investigations, it can be seen that the theory of vehicle-bridge coupling vibration under the continuous rigid-frame bridge system is now mature after nearly 70 years of research. However, the research focus is mainly on the vehicle-bridge coupling vibration response of the undamaged continuous rigid-frame bridge, while the research on the dynamic response of the damaged continuous rigid-frame bridge under vehicle-bridge coupling vibration is still insufficient. Using modified concrete bridge damage parameters [17; 18], [PERSON] et al. [19] carried out a vehicle-bridge coupling analysis of a damaged three-span continuous concrete box beam with variable sections and pointed out that the impact coefficient of the multi-span variable sections of the damaged beam varied with the vehicle speed and was related to the crack parameters. [PERSON] et al. [20] studied the vehicle-bridge coupling response of an old concrete truss arch bridge by combining a real bridge detection method and finite element modeling and then gave the impact coefficient of different bridge locations under different vehicle speeds. [PERSON] et al. [21] analyzed the vehicle-bridge coupling vibration of an in-service curved-string truss bridge based on an analysis method that considered the jump-off period and calculated the dynamic response of the space vehicle fleet crossing the bridge. However, structural diseases such as beam cracking, steel corrosion, and the local spalling of concrete are also very common in continuous rigid-frame bridges. In addition, this type of bridge has developed rapidly and in large numbers in northwest China (especially in Shaanxi Province).