Transverse Dynamic Mechanical Behavior of Hangers in the Rigid Tied-Arch Bridge under Train Loads

Abstract

The rigid hanger is one of the main load-bearing components in a rigid tied-arch bridge that is common used in high-speed railway lines, and the mechanism for influences of train loads on the hangers’ transverse vibration -still requires clarification. This paper investigates the transverse vibration of rigid hangers in the rigid tied-arch bridge under train loads from three foci. Firstly, the accurate finite-element model of a rigid tied-arch bridge and the sub-model of each hanger of this bridge are established. The dynamic characteristics analysis of the whole bridge and each hanger are presented. Secondly, because the resonance theory used for stay cables and main girder cannot be used for rigid hangers in arch bridges, the hanger’s transverse vibration formula with consideration of the interaction of rigid hangers and main girder is proposed based on the classic structural dynamics. Thirdly, a simplified load model that can reflect the mechanical characteristics of high-speed rail Electric Multiple Units is established. The transverse dynamic displacements of hangers and their dynamic amplification factors in 6 field load cases are presented by nonlinear dynamic analysis; and also they have been validated based on the data from the structural health monitoring system. The conclusions show that generally the resonance between hangers and main girder is unlikely to happen in a rigid tied-arch bridge and the transverse dynamic displacement at long rigid hangers and the dynamic amplification factors of transverse dynamic displacements at short rigid hangers are required to be paid more attention; moreover, the parameters that affect the transverse vibration of hangers have been determined; finally, the geometry, cross sectional form, the spatial location of hangers and train speed can affect the transverse dynamic mechanical behavior of hangers. This work also gives a suggestion which lays a foundation for the better design, maintenance and long-term monitoring of hangers in a long-span rigid tied-arch bridge.