Dynamic characteristics analysis and parametric study of a super-long-span triple-tower suspension bridge

摘要

Based on the Taizhou Yangtze River Bridge, a 3D finite element model is developed to establish its deformed equlibrium configuration due to dead loading. Strating from deformed configuration, a modal analysis is performed to provide the frequencies and mode shapes. The study focuses on the effects of the vertical, lateral and torsional stiffness of the steel box girder, the rigid central buckle and the elastic restraints connecting the towers and the steel box girder on the dynamic characteristics of the triple-tower suspension bridge. The results show that, variation of vertical, lateral and torsion stiffness of stiffening girders have effects on the vibration frequency in corresponding directions only and have little effects in other directions. The elastic restraints have a more significant effect on the dynamic characteristics than the central buckle, and decreasing the stiffness of the elastic restraints results in the appearance of a longitudinal floating vibration mode of the bridge. The results obtained could serve as a valuable numerical reference for analyzing and designing super-long-span tripletower suspension bridges.