【作者】 胡月伟；

【导师】 李进；

【作者基本信息】 西安建筑科技大学 ， 桥梁与隧道工程， 2011， 硕士

【摘要】 随着我国经济的飞速发展,交通建设量也得到了前所未有的加大,为了满足较大的跨度,预应力混凝土斜拉桥成为桥梁领域的主角之一,得到了广泛的运用;它出色的跨越能力和明显的结构特点使得该桥型跨度不断增大,成为中大跨度桥梁比选的佼佼者。我国是一个地震多发的国家,每当地震发生,公路线就成了生命线,而桥梁就成了构成生命线的关键点。桥梁的破坏与否将直接成为救灾与灾后重建工作能否顺利开展、经济能否快速恢复的决定因素,故而与生命息息相关。因此,作为有效实行抗震措施、建立合理抗震结构体系的科学根据,研究掌握桥梁的抗震能力、地震反应就显得至关重要。本文在结合国内外相关成果的基础上,以苏通大桥为实际工程背景,对斜拉桥的动力特性及地震响应进行了如下研究:(1)首先分析了目前大跨度斜拉桥的结构特点,设计参数以及它的发展状况,并对其抗震设计的现状,指出抗震反应分析的必要性;再对大跨斜拉桥地震响应分析中存在的问题进行探讨与分析,得出了本文所要分析的重点问题;(2)其次系统地阐述、归纳总结了桥梁地震响应分析方法——反应谱法,并对其基本假定,适应范围,分析过程与步骤以及该方法中存在的问题等进行了详尽的推演与修正;(3)利用大型有限元分析计算软件MIDAS CIVIL,通过对斜拉桥结构进行适当简化,建立其空间计算模型作为进行动力特性与地震响应分析的基础,在不考虑桩基与地基土对桥梁作用的情况下,计算斜拉桥的自振特性;(4)以上述结构的空间模型计算结果为依据,对设置了减震耗能装置与不设该装置斜拉桥的自振特性与振动特点进行对比分析,并得出分析结论;同时分析了大跨度斜拉桥在一致激励下的地震响应的反应谱分析,分别探讨在单向地震输入与组合输入下,对桥梁结构响应的影响,总结地震输入方向对大跨度斜拉桥计算结果的影响;最后通过对有阻尼与无阻尼模型关于地震响应结果进行对比,得出减震耗能装置对斜拉桥的抗震性能影响的结论。更多还原

【Abstract】 With the rapid development of China’s economy, traffic-building has also been an unprecedented amount of increase, in order to meet the demand of larger span, prestressed concrete cable-stayed bridge, one of the most popular bridge styles, has been widely used; its excellent crossing capacity and remarkable structural features make this type bridges’span increase day by day and become the leader in long-span bridges alternatives. China is the country prone to earthquakes, when the earthquake occurred; the road line became lifeline, as the bridge became the key point of the lifeline. It is the determinant to reconstruction work carried out smoothly and the rapid economy recovery whether the bridge was damaged or not, so the bridge is closely related with life. Therefore, it is vital to implement effective seismic measures and scientific researches and to establish a reasonable system of seismic structure and to grasp the seismic capacity of bridges.In this paper, on the basis of the relevant results at home and abroad, Su Tong Bridge is considered to be the practical engineering background, the analysis on the dynamic properties and seismic response of cabled-stayed bridge is the following:(1) Firstly, analyze the structure characteristics of current long span cable-stayed bridge and the design parameters and status of its development, and the status of seismic design, point out the necessity of earthquake response analysis; then the problems in cable-stayed bridges seismic response analysis are proposed and analyzed; obtain the key issues to be analyzed in this paper.(2) Followed by systematic exposition and summarizing the seismic response analysis method, response spectrum method, including its basic assumptions, the adaption scope of the analysis process and the steps, the deduction and correction to the problems of the method in details, etc.(3) At the same time, the finite element analysis software MIDAS CIVIL is used and the appropriate simplification of the cable-stayed structure is taken out to establish the spatial model as the basis of dynamic properties and seismic response analysis. On the circumstances of ignoring the interaction of pile and bridge foundation soil, the calculation of vibration characteristics of cable-stayed bridge is carried out;(4) Finally, according to the results of the bridge structure model, the vibration characteristics and modes analysis comparison is made between setting damping device and not setting the device in the cable-stayed bridge vibration. Some conclusions are drawn. Also, the response spectrum analysis is carried out under uniform excitation, the seismic response analysis effect is made, respectively, in the way of single seismic input and combined seismic input, and then it is necessary to summary the impact to the results of different seismic input direction of the span cable-stayed bridge. At last, the seismic response results comparison between having the damping device and not having damping device is executed to draw the conclusion to the damping device affecting the seismic characteristics.更多还原