【作者】 陈羽；

【导师】 张亮亮；

【作者基本信息】 重庆大学 ， 桥梁与隧道工程， 2010， 硕士

【摘要】 随着设计理论和计算方法的进步,斜拉桥技术得到了十分迅速的发展。由于斜拉桥跨径的不断增大,桥梁结构越来越轻柔,自振频率也越来越低,对风的作用也更加敏感,气动弹性问题经常会成为结构强度、刚度和稳定性设计的制约因素。因此,抗风问题已成为决定建造大跨度桥梁成功与否的关键问题之一。桥梁涡激振动是大跨度桥梁在低风速下很容易出现的一种重要的气动弹性现象。尽管涡激振动不像颤振、驰振那样会引起整个结构失效,但由于是在低风速下很容易发生的振动现象,况且振幅之大足以影响行车安全,还可能造成结构刚度破坏、从而影响行人和车辆的舒适性以及缩短构件的疲劳寿命。因而对桥梁涡激振动进行研究是很有必要的。本文以某跨海大桥为工程背景,通过该大桥的主梁节段模型风洞试验和全桥气动弹性模型风洞试验来研究桥梁涡激振动,研究其施工状态和成桥状态的涡激振动响应情况,从而对桥梁结构风致涡振响应做出综合评价,为该跨海大桥提供可靠的抗风设计参数,也为以后同类桥梁结构的抗风设计提供参考。本文研究的主要内容如下:在节段模型试验中,试验模型包括三种:主梁推荐方案、主梁比较方案一和主梁比较方案二。模型缩尺比均为1:60,长均为1.25m,宽约0.5m,长宽比约为2.5;各模型分为有、无栏杆两种配置。通过试验得到了涡激振动的临界风速,并分析了栏杆、风攻角对涡激振动的影响。试验结果表明:主梁推荐方案、主梁比较方案一和主梁比较方案二都会发生不同程度的涡激振动。在全桥气动弹性模型试验中,分别就全桥状态、最大单悬臂状态、最大双悬臂状态的涡激振动进行了研究;对独塔的涡激振动性能进行了探讨;并分析了栏杆、风速和风向角对涡激振动的影响以及未发现明显的大幅涡激振动的原因。试验结果表明:在试验的各状态下,主梁及桥塔均未发现有害的涡激振动。更多还原

【Abstract】 Because of the design theory and calculation method of progress, cable-stayed bridge has been very rapid development. However, As cable-stayed bridge span to the growing,bridge structure Becomes more and more gentle, more and more low natural frequency, and more sensitive to wind. aeroelastic problems often become design constraints of the structural strength, stiffness and stability. Therefore, the wind has become the key issues to decide whether the long-span bridges is successful or not.Vortex-induced vibration of the bridge is an important aeroelastic phenomena, it is easy for long-span bridges to occur Vortex-induced vibration.Although the vortex-induced vibration would not cause the structural failure, as the flutter or the buffeting,but it’s very susceptible to occur at a low wind speed, moreover amplitude large enough to affect traffic safety, and cause stiffness damage, thus affecting the comfort of pedestrian and vehicle, and reducing fatigue life. Thus it is necessary to study vortex-induced vibration of bridge.This paper bases on a sea bridge, through the bridge section model wind tunnel tests of the main beam and full bridge aeroelastic model wind tunnel tests to study vortex-induced vibration of bridges, studying the vortex induced vibration response of it during construction state and full bridge state, and make comprehensive evaluation of vortex induced vibration of bridge structure, providing reliable wind parameters to the bridge design, and providing a reference for the future similar bridges design.The main contents as follows:In section model test,section model consists of four models: the recommended Scheme of girder, the first comparative scheme of girder, the second comparative scheme of girder. The scale of all of the Model is1:60, Length is 1.25m, width is 0.5m, length to width is about 2.5. Each model includes two configurations: railing and without railing. Through experiments, the critical wind speed of the vortex-induced vibration is received. And analyzed effect of the railing and the wind attack angle on the vortex-induced vibration. The test results showed that: the recommended Scheme of girder, the first comparative scheme of girder and the second comparative scheme of girder all occur vortex-induced vibration.In the full-bridge aeroelastic model tests, vortex-induced vibration of full-bridge states, the largest single-cantilever state and the largest double cantilevers state has been studied; The vortex-induced vibration properties of the single tower has been discussed; And analyzed the effect of the railing, the wind speed and wind direction on the vortex-induced vibration, and the reason for no obvious vortex-induced vibration. The test showed that: in each test state, the harmful vortex-induced vibration has not been found in the main beams and the bridge towers.更多还原