The dynamic behaviour of bridge bearings for railway bridges under running vehicles

초록

Open steel plate girder (OPSG) bridges are the most prevalent railroad bridge type in Korea, constituting about 40% of all railroad bridges. Solid steel bearings, known as line type bearings, are placed in most OSPG railway bridges. However, the line type rigid bearings generate several problems with the bridge's dynamic behaviour and maintenance in service. To compare and investigate the dynamic behaviour of line type, spherical and disk bearings, the vertical displacements of each bearing, including fixed and expansion type, under running vehicles are measured and analysed. The displacements of disk and spherical bearings are measured after replacing the line type bearings with spherical and disk bearings. This study also analysed the dynamic behaviour of bridges. Furthermore, the deformation of the polytetrafluoroethylene (PTFE) plate that is placed inside of expansion type spherical and disk bearings is measured and its effect on the dynamic behaviour of the bridges is discussed. The up-lift phenomenon at the bearings installed for the steel bridges is estimated. The vertical displacements at mid-span of the bridges are compared according to the bearing types. Finally, the first mode natural frequencies are estimated, and the relationship to the vertical displacement is discussed. © Civil-Comp Press, 2012

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