大跨度钢管混凝土拱桥整体吊装法施工的抗风研究

Study of Wind Resistance of Long-Span Concrete-Filled Steel Tube Arch Bridge Erected by Integral Lifting Method

南昌生米大桥主桥为两主跨跨径228 m的钢管混凝土连拱,该桥主拱肋的施工在国内首次使用大型门式膺架进行整体吊装,为了保证该桥主拱架设期间的安全,对其进行了风洞试验。首先给出了主拱肋的动力特性计算结果,然后对风洞试验的结果进行了分析,重点讨论了主拱肋最大悬臂状态和合龙状态的风偏角影响以及上游已安装拱肋的尾流对下游拱的影响。结果表明,主拱肋在施工期间未出现涡激振动,先架设的上游拱对后架设的下游拱的动力响应有影响。

The main bridge of the Shengmi Bridge in Nanehang is a concrete-filled steel tube multi-arch bridge with two main spans each 228 m in length, whose main arch ribs are erected for the first time in China by integral lifting method with giant gantry. To ensure the safety of the bridge during erection of main arches, the wind tunnel tests for the erection of the ribs have been conducted. In this paper, the computations of dynamic performance of the main arch ribs are given and the results of wind tunnel tests are analyzed, in which the paper mainly discusses the influenees of wind offset angles on the areh ribs in the state of their longest cantilevers and closure, and influences of wake flow from the erected arches at the upstream side on the arches at the downstream side. The results of computations and analysis herewith reveal that vortex-induced vibration will not occur in course of the erection of the main arches, however, and the earlier eretted upstream arches will have influences on the dynamic response of the later erected downstream arches.