基于结构参数变化对结合梁自锚式悬索桥动力特性的分析

Analysis on Dynamic Characteristics of Self-anchored Suspension Bridges with Combined Beams Based on Structural Parameter Variations

借助Midas/Civil建立合理动力全桥模型,结合梁自锚式悬索桥自振特性规律,虚设一座相同参数的地锚式进行比较,探讨恒载集度、主梁刚度、桥塔刚度、主缆抗拉刚度、吊索抗拉刚度等主要参数对结合梁自锚式悬索桥固有频率的影响。研究表明:在狭窄的频率范围内,振型较为集中,且前几阶振型以主梁振动为主;恒载倍率增加对一阶振型频率均有减小作用,主梁竖向刚度增加对一阶竖弯振型影响较大,桥塔纵向刚度增加使纵漂频率显著增加,主缆抗拉刚度倍率增大使主梁扭转振型频率增加显著,吊索抗拉刚度倍率增大对一阶振型频率影响很小。

With the help of Midas/Civil, a reasonable dynamic full bridge model is established to study the natural vibration characteristics of self-anchored suspension bridges with composite beams, and a ground anchor type with the same parameters is assumed to be compared. The effects of the main parameters such as dead load concentration, girder stiffness, tower stiffness, main cable tension stiffness and suspension cable tension stiffness on natural frequencies of self-anchored suspension bridges with composite beams are discussed. The results show that the vibration modes are concentrated in the narrow frequency range, and the main beam is the dominant vibration mode in the first few order. The frequency of the first-order mode decreases with the increase of constant load ratio. The increase of the vertical stiffness of the main girder has a great influence on the first-order vertical bending mode shapes. The frequency of longitudinal drift increases significantly with the increase of longitudinal stiffness of bridge towers. The torsional mode frequency of the main beam increases significantly with the increase of the tensile stiffness ratio of the main cable. The increase of the tension stiffness ratio of the suspension cable has little effect on the first mode frequency.