【作者】 易灵芝；

【导师】 伍衡山；

【作者基本信息】 南华大学 ， 结构工程， 2008， 硕士

【摘要】 本文就公路车辆-桥梁系统耦合振动性能开展了如下研究:(1)把桥梁和车辆视为一个相互作用系统,提取可能对车-桥振动体系产生重要影响的参数,对车、桥两个振动系统进行整体的、细致的分析。通过具体算例,探讨了车辆模型、速度、质量、桥梁阻尼以及跨径等参数对车-桥耦合系统振动性能的影响。(2)研究了桥梁在不同上桥初速度以及加速度的变速移动荷载作用下的动力响应以及桥梁跨中挠度动力放大系数,研究结果表明:速度对桥梁动力系数的影响是一个复杂的过程,并不是速度越大,动力响应就越显著。车辆荷载变速与匀速通过桥梁时的动力放大系数均不随速度变化成简单的线性关系,而是随着速度增大呈类正弦且振幅逐渐增大形式。(3)考虑桥面不平顺的随机激励作用,对车辆在路面不平顺状态下的桥梁振动响应以及冲击系数进行了研究,其结果表明:①桥面不平顺加剧了桥梁的振动,随着桥面不平整波长的变化,动态增量会产生峰值,这是车桥耦合系统发生共振的缘故。因此,在桥梁设计与施工中,为了减小其动态增量,可根据桥梁上主要运行车辆的速度,对桥面平整度加以控制,尽量避免共振的产生。②动态增量随速度变化而产生较大变化,但并非线性增加,在某些速度点上,会有峰值产生,这也是共振的缘故。如果这个理论的速度共振点在可实现的范围内,为了限制桥梁的振幅,我们有必要对速度共振点进行监控。③动态增量随跨径变化而产生较大变化,当车辆频率和桥梁频率接近时,动态增量出现了峰值。并且随着跨径增大,动态增量有减小的趋势。影响冲击系数的因素很复杂,制定适合我国公路桥梁荷载的放大谱仍需要进行大量的研究工作。本研究获得了大量车-桥耦合振动规律,较真实的反映桥梁结构在车辆荷载作用下的动态受力和变形本质,为工程结构的设计和施工提供可靠的参考。更多还原

【Abstract】 This thesis deals with the following aspects concerning the coupling vibration performanceof vehicle-bridge system.1.The important influencing parameters of vehicle-bridge vibration system were extractedafter combing bridge and vehicle as an interaction system. Then they were analyzed as a wholeand carefully. The parameters affecting vibration performances, such as model, velocity, quality,damping, and span, were studied by some concrete examples.2.The dynamic response under variable speed moving load of different initial velocity andacceleration, and magnification factors of mid-span deflection were mainly discussed. Theresults showed that the effect of velocity to bridge dynamic coefficient was complex, that is tosay, the larger the velocity, nor the more significantly the dynamic response. There was nolinear relationship between magnification factors of load under variable speed and uniformmotion and velocity, while they were showed as sine, the more velocity, the larger amplitude.3.Considering the invigorative function of bridge deck irregularities random, the bridgevibration response under the condition of uneven pavement was analyzed by legend. Finally theimpact coefficient was also studied. The results showed below. Firstly, the uneven pavementaggravated the bridge vibration. The dynamic increment gave rise to peak changed withwavelength as a result of resonance in coupling system. So the smoothness of pavement shouldbe controlled and avoided resonance to decrease dynamic increment in bridge design andconstruction. Secondly, the dynamic increment changed with velocity, nor the linear increase.Peak formed at some velocity points because of resonance. If the velocity points in therealization range, it is necessary to monitor velocity points to the bridge amplitude. Thirdly, thedynamic increment also changed with span, and the peak formed when frequency of vehiclewas close to that of bridge. Additionally, the dynamic increment decreased with an increase ofspan. That’s basically identical to the previous reports. The factors that influence impactcoefficient are very complex. Therefore, more research should be carried out on establishingsuitable amplified spectra of highway bridge load in China. A lot of vibration regularity achieved in this paper reflected the dynamic force andessential deformation of structure under the load of vehicle-bridge realistically. It’s hoped thatthese results could provide reliable reference for engineering structuredesign and construction.更多还原