Abstract
Taking the simply supported box girder bridge of high-speed railway as an example, the effect of cross-sectional decentralized centre of mass and shear on the spatial beam element stiffness matrix was theoretically derived. Based on the vehicle-bridge coupling vibration analysis method of the railway bridge, an analysis program of vehicle-bridge coupling vibration for the high-speed railway was compiled, and its reliability was verified through an example analysis. On this basis, considering the cross-sectional decentralized centre of mass and shear, the influence factors of vehicle-bridge coupling vibration response were studied, which included the offset distance of the beam section’s mass and shear centre, offset distance of track centreline, vehicle weight, and vehicle speed. The results show that the additional items of the spatial beam element stiffness matrix are generated by the torsion effect when the cross-sectional decentralized centre of mass and shear is considered, and it will affect the lateral and vertical stiffness of the element. The cross-sectional decentralized centre of mass and shear has a significant effect on the lateral dynamic response of the bridge’s mid-span, but the influence on the vertical response of the bridge and the dynamic response of the car body is small. The main influence factors of the lateral dynamic response of the bridge are the vertical offset distance of the beam section’s centre of mass and shear, the lateral offset distance of the track centreline, and the vehicle weight.
Highlights
In the numerical analysis of coupled bridge-vehicle-bridge vibrations, spatial beam units are often used in discrete bridge structures
To improve the efficiency and accuracy of calculating the structural deformation and internal forces of beam units, many scholars have used Timoshenko beam theory as the basis for deriving the stiffness matrix of spatial beam units considering shear effects by specifying a reasonable form function for the unit deformation and combining it with the principle of minimum potential energy or virtual work [1]. These papers all implicitly assume that the centre of mass of the unit section coincides with the centre of shear. is is undoubtedly accurate for symmetrical regular section beams, but in engineering practice, many structural members have irregular cross sections, where the mass and shear centres are often not in the same position, known as “section mass-shear heterocentricity,” which will produce certain deviations in the beam unit stiffness matrix and affect the stiffness distribution of the whole bridge structure
Guo et al [6] established a finite element model of high-speed railway bridges and used the bridge-rail deformation mapping model to calculate the rail deformation caused by bridge deformation and as an excitation of the vehicle-rail-bridge system to study the effect of bridge deformation on the dynamic response of trains
Summary
Taking the supported box girder bridge of high-speed railway as an example, the effect of cross-sectional decentralized centre of mass and shear on the spatial beam element stiffness matrix was theoretically derived. Based on the vehicle-bridge coupling vibration analysis method of the railway bridge, an analysis program of vehicle-bridge coupling vibration for the highspeed railway was compiled, and its reliability was verified through an example analysis On this basis, considering the crosssectional decentralized centre of mass and shear, the influence factors of vehicle-bridge coupling vibration response were studied, which included the offset distance of the beam section’s mass and shear centre, offset distance of track centreline, vehicle weight, and vehicle speed. E main influence factors of the lateral dynamic response of the bridge are the vertical offset distance of the beam section’s centre of mass and shear, the lateral offset distance of the track centreline, and the vehicle weight On this basis, considering the crosssectional decentralized centre of mass and shear, the influence factors of vehicle-bridge coupling vibration response were studied, which included the offset distance of the beam section’s mass and shear centre, offset distance of track centreline, vehicle weight, and vehicle speed. e results show that the additional items of the spatial beam element stiffness matrix are generated by the torsion effect when the cross-sectional decentralized centre of mass and shear is considered, and it will affect the lateral and vertical stiffness of the element. e cross-sectional decentralized centre of mass and shear has a significant effect on the lateral dynamic response of the bridge’s mid-span, but the influence on the vertical response of the bridge and the dynamic response of the car body is small. e main influence factors of the lateral dynamic response of the bridge are the vertical offset distance of the beam section’s centre of mass and shear, the lateral offset distance of the track centreline, and the vehicle weight
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