Influence study of main cable displacement-controlled device type of long-span suspension bridges on structural mechanical properties

Abstract

Main cable displacement-controlled devices (DCDs) are key components for coordinating the vertical deformation of the main cable and main girder in the side span of continuous suspension bridges. To reveal the mechanical action mechanisms of DCD on bridge structures, a three-span continuous suspension bridge was taken as the engineering background in this study. The influence of different forms of DCD on the internal force and displacement of the components in the side span of the bridge and the structural dynamic characteristics were explored through numerical simulations. The results showed that the lack of DCD caused the main cable and main girder to have large vertical displacements. The stresses of other components were redistributed, and the safety factor of the suspenders at the side span was greatly reduced. The setting of DCD improved the vertical stiffness of the structure. The rigid DCD had larger internal forces, but its control effect on the internal forces at the side span was slightly better than that of the flexible DCD. Both forms of DCD effectively coordinated the deformation of the main cable and main girder and the stress distribution of components in the side span area. The choice of DCD form depends on the topographic factors of bridge sites and the design requirements of related components at the side span.

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