城市轨道交通高架桥箱梁结构振动特性分析

随着轨道交通快速发展,其引起的振动噪声问题日益突出。为了研究高架轨道箱梁结构振动特性,基于车桥耦合动力学分析模型,利用多体动力学与有限元法求解箱梁结构的振动响应,并从时域和频域两个角度对轨道箱梁结构的振动特性进行分析,研究发现:(1)列车以80 km/h的速度过桥,车致振动自上而下在轨道结构间传递时,扣件全频段减振效果明显,CA砂浆层的减振效果不佳。(2)箱梁桥的翼板竖向振动响应水平最大,腹板次之,顶板和底板较小,在进行箱梁振动控制研究时应重点关注翼板和腹板的振动。(3)箱梁桥不同截面位置振动的模态贡献存在差异,跨中截面以1阶竖弯振动为主,2阶竖弯振型对1/4截面振动贡献最大,3阶竖弯振型对梁端截面的振动响应贡献最大。

Analysis of Structural Vibration Characteristics of Elevated Track Box Beam Bridge

With the rapid development of rail transit,the vibration and noise problems have become increasingly prominent.In order to study the vibration characteristics of the elevated box beam structure,multi-body dynamics and finite element method are used to solve the vibration response of the box beam,and vibration characteristics are analyzed from two aspects of time domain and frequency domain based on vehicle-bridge coupled dynamics analysis model.The results show that:(1)When the train passes the bridge at the speed of 80 km/h and the vibration caused by the vehicle transmits from top to bottom between track structures,the damping effect of the fastener is obvious and the CA mortar layer has poor damping effect.(2)The vertical vibration response level of the wing is the strongest,and that of the web is next to it;as the top plate and the bottom plate are small,the vibrations of the wing and the web should be addressed in the research on the vibration control of the box beam.(3)The modal contribution of the vibration of different cross-section is various.The mid-span section is dominated by 1st-order vertical bending vibration,the 2nd-order vertical bending vibration mode contributes the most to 1/4 section,and the 3rd-order vertical bending vibration mode contributes the most to beam-end section.