三塔两跨悬索桥行波效应振动台试验及数值研究

为了研究行波效应对大跨多塔连跨悬索结构抗震性能的影响，以泰州长江公路大桥为背景，设计并制作1/40缩尺比例模型，进行了全桥振动台模型试验。采用中塔与主梁间弹性索连接的纵向约束结构体系，试验分别测试了不同视波速下行波效应对全桥位移响应的影响。振动台试验表明，考虑行波效应时，中塔顶位移、北塔梁纵向相对位移会有明显增大，最大增幅在50%以上；主桥梁与引桥梁纵向相对位移也会有明显增大，增大幅值在1倍以上。因此，仅考虑一致地震激励不能保证大跨度多塔悬索桥的结构安全。通过比较试验结果和数值计算结果可以发现，试验结果与有限元数值模拟结果较为接近、吻合较好。数值计算所采用的绝对位移法分析行波效应方法操作简单，力学概念清晰，可方便的应用到大跨度桥梁行波效应分析中。

Shake table test and numerical analysis on wave passage effect of three-tower two-span suspension bridge

In order to study wave passage effect of long-span multi-tower suspension structure, a 1/40 scale of Taizhou Changjiang Highway Bridge was designed, constructed and tested on the shaking table. Elastic cable devices were designed by adopting connecting methods between the main beam and middle tower. The shake table test method was used to consider the wave passage effect and the seismic response under different apparent wave velocity was studied. The test results show that structural displacement response increased remarkably under wave passage effect in comparison with uniform excitation: the top longitudinal displacement of middle tower and relative displacement between main beam and north tower increased more than 50 percent; the relative longitudinal between main beam and approach beam increased more than 1 times. Therefore，only considering uniform excitation is unsafe to long-span multi-tower suspension bridge. Comparing the shaking table test with numerical analysis, it is found that the numerical value and shape of displacement time histories is consistent in both. The numerical analysis of wave passage effect by absolute displacement method is simpler, mechanics concepts of this method is very clear. Absolute displacement method can also be used for wave passage effect of long-span bridge.