变截面连续钢箱梁桥典型施工阶段涡激振动

为探讨大跨度连续钢箱梁桥在吊装施工阶段可能遇到的风致涡激振动问题，提出有效的抑振措施，以崇启6跨变截面连续钢箱梁主桥施工过程为背景，通过 1:45全桥气弹模型风洞试验，研究了大跨度变截面连续梁桥典型施工阶段主梁的涡激振动性能，试验模拟了外加阻尼的抑振措施，并基于试验现象探讨了连续钢箱梁桥的涡激振动机理.研究结果表明:当第2跨主梁架设完成后，主梁易产生涡激振动，且不满足桥梁抗风设计规范的要求.当结构阻尼比达到1.2%时，涡激振动振幅满足规范要求；当结构阻尼比达到2.1%时，施工阶段不会产生明显的涡激振动. 

Vortex-Induced Vibration of Continuous Steel Box-Girder Bridge with Variable Cross-Sections at Typical Erection Stages

In order to investigate the vortex-induced vibration performances of a long-span continuous steel box-girder bridge during erection to propose effective mitigation measures, the erection of a six-span continuous variable cross-section steel box-girder bridge was regarded as an engineering example. Its vortex-induced vibration at typical erection stages was investigated through aeroelastic model wind tunnel tests with a geometric ratio of 1 to 45, and additional damping ratio was applied to mitigate vortex-induced vibration. The mechanism of the vortex-induced vibration was discussed based on the test phenomenon. The research results show that the bridge may suffer serious vortex-induced vibration after the 2nd span is completed, and the vortex-induced vibration will exceed the specification limit. If the damping ratio is up to 1.2%, vortex-induced vibration amplitude can meet the specification requirement, and if the damping ratio is up to 2.1%, the vortex-induced vibration will be suppressed effectively.