【作者】 张龙奇；

【导师】 郑史雄；

【作者基本信息】 西南交通大学 ， 桥梁与隧道工程， 2011， 硕士

【摘要】 随着我国交通运输事业的迅速发展,高速铁路的大量建设,为了跨越江河天堑,作为其控制性工程的大跨度桥梁也大量出现。钢桁拱桥因其刚度相对较大,在铁路建设中也逐渐越来越多地使用。然而大跨度钢桁拱桥刚性长吊杆因其自身的特点对自然风作用较为敏感,容易发生风致振动破坏,故对其采取合理的减振措施对桥梁的运营安全有着重要意义。本文以京沪高铁某大桥为工程实例,对刚性长吊杆的减振措施进行了研究分析,主要工作如下：(1)对国内外的钢拱桥发展历史及自然风作用下发生风毁的拱桥进行了总结,简要介绍了风对桥梁结构的静力及动力作用,吊杆结构的弛振与涡激振动理论,以及结构减振措施的研究现状。(2)基于有限元理论利用ANSYS软件对该大桥建立全桥有限元模型,并进行全桥动力特性分析,建立节段模型计算出最长吊杆的基阶频率。(3)通过对对最长吊杆的风洞试验与理论分析,得出其在自然风作用下有发生弛振与涡振的可能性,并分析总结其风致振动的影响因素。比较分析了主动控制措施、改变气动外形方法、安装调质阻尼器方法和顺桥向不同位置增设拉杆的方法,对各种措施的减振效果进行了研究。结果表明各种措施都在一定程度上减小了吊杆的风致振动,对将来同类桥梁的吊杆结构设计具有一定的借鉴和指导意义。更多还原

【Abstract】 With the booming development in transportation, a large number of High-speed railways are constructed in China. Long span bridges, as the controllable engineering for crossing rivers and natural chasm, appeared in abundance accordingly. More and more steel truss arch bridges are erected in railway construction as to their relatively greater stiffness. However, the characteristics of the slender suspender of long span steel truss bridge is more sensitive to the wind action, which is prone to occur wind-induced vibration. As a consequence, there is remarkable significance to adopt reasonable restriction measures for the bridge operational safety.In this thesis, taking a bridge in Beijing-Shanghai express railway as the project example, it studies the restriction measures for stiffening slender suspender, including following aspects:(1) This thesis is giving a summary of the history of steel arch bridges and the wind destroied arch bridges at home and abroad, which briefly introduces the static and dynamic wind effects on bridge structures, the theory of galloping and vortex-induced vibration of suspenders, and the current research situation in structure restriction measures.(2) The structural dynamic characteristics of the bridge are analyzed by using ANSYS to build the finite element model, and the longest suspender’s frequencies are figured out with the segmental model on the basis of finite element theory. There is theory formula given to calculate the longest suspender’s frequencies.(3) Wind tunnel test and theory analysis indicate the probability of galloping and vortex-induced vibration to the longest suspender. The wind-induced vibration influencing factors are analyzed and summarized. Then restriction measures are discussed such as implementing the active control methods, changing the aerodynamic shape, installing tuned mass damper (TMD), and setting longitudinal rod, of which the effects of vibration reduction are researched followed. Analysis results show that each measure can partly decrease the wind-induced vibration, which is instructive to the design of the similar suspender structure bridge in the future.更多还原