自锚式混凝土悬索桥的动力分析

研究自锚式混凝土悬索桥的动力学性能 .以一新建自锚式混凝土悬索桥为背景 ,首先运用有限元分析获得其动力特性并与地锚式悬索桥进行比较 ,然后利用实桥环境振动试验验证有限元动力特性分析结果 ,最后由地震反应分析进一步考察自锚式悬索桥的振动特点 .结果表明 :自锚式悬索桥由于主缆直接锚固于主梁端 ,主塔纵向弯曲振动频率明显降低 ;因结构耗能方式也随之发生了变化 ,主塔和主梁在纵向地震输入下的各种反应均呈不同程度的增加 .

Dynamic Analysis of Self-anchored Concrete Suspension Bridge

The dynamic performance of a newly constructed self-anchored concrete suspension bridge is investigated in this paper.A 3-dimensional finite element (FE) model is established first to obtain the dynamic characteristics of the bridge.Then ambient vibration test is conducted on the bridge and the FE model is thereby validated.Finally,the seismic responses of the bridge under longitudinal earthquake inputs are evaluated with the response spectrum method based on the FE model.An imagined earth-anchored concrete suspension bridge,which is the same as the actual self-anchored bridge except the way of the anchoring of the main cables,is also analyzed for the sake of comparison.The differences in the dynamic behavior between the two bridges are examined in detail.It is found that the natural frequencies of the longitudinal bending modes of the tower of the self-anchored bridge are decreased compared with the corresponding earth-anchored bridge.In addition,the energy-dissipating mechanics under earthquake inputs is different between the two types of bridges and the seismic internal forces and displacements of the self-anchored bridge are greater than those of the earth-anchored bridge.