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• The impact test results of the scaled model corresponding to the finite element model were used to verify the accuracy of the adopted material models and contact relationships. • Based on the spatial complexity of urban overpasses, the dynamic responses and failure mode of the full-bridge model under non-bottom impact were numerically simulated. • Four comparative models were established to study the effect of the bridge model parameters on impact responses. Urban viaducts are likely to be subjected to non-ground-level vehicle collisions during their service life period. However, current research primarily focus on vehicle impacts on the bottom of bridge piers. In this research, a full-bridge scale model impact test was conducted to validate the accuracy of the finite element (FE) model. Then, LS-DYNA is used to establish refined vehicle-bridge collision FE models. The dynamic responses and failure mode of the pier impacted by the non-bottom vehicle are investigated. Besides, the effects of bridge structure spatial stiffness, superstructure mass, and double-column structure on the impact responses of bridges are analyzed. The results show that vehicle collisions are characterized by a continuous impact action involving multiple components. The damage to the full bridge model is concentrated in the directly impacted double-column pier, where the head-on column sustains three-point bending damage, the indirectly impacted column sustains bending damage at the top and bottom, and the cover beam sustains tensile shear damage. The non-bottom impact significantly increases displacements and bending moments of the pier while causing a substantial decrease in bottom shear. The impact responses of the pier are greatly influenced by the superstructure mass and double-column structure, while the spatial stiffness of the bridge has minimal affection. [ABSTRACT FROM AUTHOR]

• A finite element model of wheel-mounted brake disc bolts is established and validated. • The high-speed EMU operation speed affects the load variation in the brake disc bolt. • Many small loads are exerted on the bolts because of the track excitations. • The amplitude and direction of the bending moment along the bolt are inconsistent. The reliability of brake disc bolts is crucial to the operational safety of high-speed electrical multi-units (EMUs). It is of great significance to investigate the bolt loads to ensure the bolt service life. A theoretical analysis is completed according to the jointed structure and the service condition of the bolts. By establishing a finite element model of the wheel-rail contact, the bolt loads of the wheel-mounted brake disc under high-speed rotation are simulated. A field experiment is implemented to obtain the dynamic loads of wheel-mounted brake disc bolts of a Chinese high-speed train based on a load test technique. The tested bolt loads include the tensile force, radial bending moment and circumferential bending moment. The simulation results are compared with the field test data. It validates the finite element model. The results indicate that the bolt loads are closely related to the operation speed of the high-speed EMU. The theoretical calculation method and the finite element method both prove that the amplitude and the direction of the radial bending moment along the bolt are inconsistent. The extrema of the radial bending moments appear in the left, middle and right cross-sections. The radial bending moment at the left cross-section is larger than that at the right cross-section because of the asymmetry of the wheel structure. [ABSTRACT FROM AUTHOR]