大跨径斜拉桥风致颤振、抖振响应控制分析

发布时间：2019-02-22 12:12

【摘要】：著名的塔科马大桥风致颤振损毁让人们意识到桥梁抗风设计在桥梁设计中举足轻重的地位。随着桥梁设计建造能力的增强,现代桥梁跨径越来越大,体系越来越轻柔,对风荷载更加敏感。桥梁抗风问题更加凸显出来。随着结构振动控制技术的迅速发展,调谐减振技术的理论研究变得更加成熟,应用也更加广泛。作为主要的调谐减振装置,调谐质量阻尼器也被广泛应用到结构防灾减灾工程中。调谐质量阻尼器是一种比较灵活有效的减振措施,能够针对不同的需求进行减振设计。调谐质量阻尼器系统能够有效地减弱结构的动力效应,广泛应用在高层建筑结构和高耸结构及桥梁的抗震抗风设计中。本文选取某大跨径斜拉桥作为工程实例,对下面几个问题作了研究:(1)研究了调谐质量阻尼器工作原理及在斜拉桥抗风中的应用进展,对其优缺点做出论述。(2)介绍了自然风和脉动风对结构的影响,研究桥梁静风稳定性,介绍扭转发散和横向屈曲临界风速的计算方法。采用谐波合成法,由目标功率谱函数人工模拟空间脉动风场,水平(顺风向)脉动风谱采用Simiu风谱模型而竖向脉动风谱采用Lumley-Pnofsky风谱模型,得到了该斜拉桥随机风场时程样本。模拟谱和目标谱吻合的较好,并且模拟各点的模拟谱也非常接近。(3)利用有限元软件ANSYS,建立阻尼器减振系统的仿真分析,得到该桥梁的三维模型,进行动力特性分析,研究调谐质量阻尼器的影响参数。通过调整控制器阻尼比参数和布置方式,对比分析其对风致颤振的影响。结果表明:布置一和较大的阻尼比能够一定程度上提高颤振临界风速;临界风速阻尼比越大,临界风速越大,但提升幅度较小。(4)改变阻尼器的布置方式和参数,对比分析不同布置方案下,阻尼器对桥梁风致侧向抖振的影响。ANSYS计算结果表明:安装了阻尼器的桥梁风致侧向抖振位移与加速度根方差减小,并且抖振控制效果与控制器的布置相关。控制器参数的合理选取,调谐质量阻尼器的优化布置,会使桥梁的风致侧向抖振的减振效果更加明显。
[Abstract]:Wind-induced flutter damage of the famous Tacoma Bridge makes people realize the importance of bridge wind-resistant design in bridge design. With the enhancement of bridge design and construction ability, modern bridge span is becoming larger and larger, the system is more and more soft, and more sensitive to wind load. The problem of bridge wind resistance is more prominent. With the rapid development of structural vibration control technology, the theoretical research of tuned vibration control technology has become more mature and widely used. As the main tuned vibration absorber, tuned mass damper is widely used in structural disaster prevention and mitigation engineering. Tuned mass damper (TMD) is a flexible and effective damping measure, which can be designed for different needs. The tuned mass damper system can effectively reduce the dynamic effect of the structure, and is widely used in the seismic and wind resistant design of high-rise building structures, high-rise structures and bridges. In this paper, a long-span cable-stayed bridge is selected as an engineering example. The following problems are studied: (1) the working principle of tuned mass damper and its application in wind resistance of cable-stayed bridge are studied. The advantages and disadvantages are discussed. (2) the influence of natural wind and pulsating wind on the structure, the stability of bridge static wind and the calculation method of torsional divergence and transverse buckling critical wind speed are introduced. Using harmonic synthesis method, the space pulsating wind field is artificially simulated by the target power spectrum function. The horizontal (downwind) pulsation wind spectrum is modeled by Simiu wind spectrum model and the vertical pulsating wind spectrum is modeled by Lumley-Pnofsky wind spectrum model. The random wind time history samples of the cable-stayed bridge are obtained. The simulated spectrum coincides well with the target spectrum, and the simulated spectrum of each point is very close. (3) using finite element software ANSYS, to establish the simulation analysis of the damper damping system, the three-dimensional model of the bridge is obtained, and the dynamic characteristics of the bridge are analyzed. The influence parameters of tuned mass dampers are studied. By adjusting the damping ratio parameters and the layout of the controller, the effect of the damping ratio on the wind-induced flutter is compared and analyzed. The results show that the flutter critical wind speed can be improved to some extent with the first and larger damping ratio. The larger the critical wind speed damping ratio is, the greater the critical wind speed is, but the smaller the lifting range is. (4) changing the layout and parameters of the damper, comparing and analyzing the different arrangement schemes, ANSYS calculation results show that the variance of lateral buffeting displacement and acceleration root of bridge wind induced by dampers is reduced, and the effect of buffeting control is related to the layout of the controller. The reasonable selection of controller parameters and the optimal arrangement of tuned mass dampers will make the wind-induced lateral buffeting of bridges more effective.
【学位授予单位】：武汉理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U441.3;U448.27

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