【作者】 朱克兆；

【导师】 赵跃宇；

【作者基本信息】 湖南大学 ， 桥梁与隧道工程， 2008， 硕士

【摘要】 随着交通事业的蓬勃发展,桥梁结构不断向大跨径和轻型化方向演变,而车辆荷载以及行车速度也在不断的提高,通过桥梁的交通量日益密集,这些变化使得车辆荷载对公路桥梁结构的动力效应变得的更加显著。大跨度斜拉钢管混凝土拱桥作为一种近年来出现的新型组合桥梁,其结构形式新颖独特,兼备了斜拉桥与拱桥的优点,目前在实际工程中已经得到了应用,但对其理论的研究尚处于起步阶段。有鉴于此,本文以湘潭市湘江四大桥为背景,就斜拉拱桥在车辆荷载作用下的动力响应问题进行分析探讨,主要开展了如下工作:(1)利用大型通用有限元软件ANSYS建立了斜拉拱桥的空间有限元模型,在考虑桥面平整度的前提下,分别针对桥面障碍、行车速度、车辆载重、阻尼和有无斜拉索的情况,对斜拉拱桥在车辆荷载作用下的动力响应进行了分析计算,探讨了冲击系数的变化趋势;(2)结合相似第二定理和量纲分析法对斜拉拱桥模型进行动力相似分析,建立了适合于车振试验需要的动力模型结构;通过斜拉拱桥模型进行车辆振动试验,测得结构实际的频率、振型和冲击系数,并与理论计算结果进行对比。分析结果表明,桥面平整度、桥面障碍、行车速度、车辆载重、阻尼等均对结构的动力响应影响很大,特别是桥面障碍;斜拉索的存在将大大改善1/4跨拱肋的在车振时的受力性能。更多还原

【Abstract】 With the flourishing development of traffic business, the bridge structure is evolving towards long-span flexibility and small quality continuously. At the same time, vehicle load and vehicle velocity are rising rapily. These variations making the effects of vehicle load on dynamic response of bridge structure become more and more remarkable. Long-span cable-stayed concrete filled steel tube arch bridge is a new pattern of combined bridge with the advantages of both cable-stayed bridge and arch bridge. Meanwhile, its unique structure has been put into practice widely. However, the theory investigation of cable-stayed arch bridge is just at the beginning. In the view of this, the dynamic response of cable-stayed arch bridge is studied in detail on the influence of vehicle load. And it base on the Fourth Bridge of Xiangjiang River in Xiangtan city. In this paper:1. Three-dimensional finite element model of cable-stayed arch bridge is established by ANSYS. And then the dynamic response of cable-stayed arch bridge is investigated on the influence of vehicle load considering the roughness of bridge deck, obstacle of bridge deck, vehicle velocity, quality of vehicle, damping and cable. Finally, the variation tendency of impact factor is discussed.2. The Second Similar Law and Dimensional Analisis Method are absored in analyzing the model of cable-stayed arch bridge and then found a dynamic model structure satisfying the need of vehicle vibration experiment. At last, we get the nature frenquency, vibration mode and impact factor of structure through the vehicle vibration experiment.The results show that the influence of bridge deck roughness, obstacle of bridge deck, vehicle velocity, quality of vehicle, damping are conspicuous to dynamic response, especially the obstacle of bridge deck. Because of the existing of cable the stress performance of quarter arch rib is improved.更多还原