考虑荷载随机性影响的桥梁振动及噪声环境研究

发布时间：2018-03-08 15:14

本文选题：随机荷载　切入点：人行桥振动　出处：《浙江大学》2014年博士论文　论文类型：学位论文

【摘要】：随着我国人车流量激增及交通空间与人居空间的紧邻化,交通、人群作用下结构振动引起的舒适性及噪声问题日益突显。本文以桥梁振动引起的舒适性问题和辐射低频噪声问题为对象,针对传统的确定性方法对在结构受力及人体感觉不确定性方面中考虑的不足,本文基于概率方法提出了能同时考虑荷载随机性及个体差异性影响的振动舒适性及声环境评价方法。一方面通过建立随机人群及车流荷载下结构振动响应计算分析体系,实现了结构响应的概率化分析；另一方面,结合已有的实验结果及标准,建立了考虑个体感觉差异性影响下,振感和噪声上的概率分布曲线,从而实现了对结构在多方面随机因素影响下的全面客观评价。通过结合实际工程的应用分析,本文的工作及得到的主要结论如下： 1、开发了精确模拟步行荷载下人行天桥振动响应的计算方法,通过与现场振动试验结果的对比,检验了算法的精度及有效性；并基于本文提出的振动舒适性评估方法,系统研究了随机人群荷载下结构振动的舒适性。结果表明,对于基频大于3Hz的人行桥,也有可能出现振动不舒适性。 2、以柔性索道桥在步伐荷载作用下的振动响应计算和舒适性评价为对象,建立了简便的索道桥非线性振动方程及算法,并通过与振动实测结果的对比验证了算法的有效性。在此基础上,研究了随机人群荷载下结构的舒适性。结果表明,柔性索道桥由于结构刚度小、频率低,在步伐荷载下易在高阶振型频率发生步伐共振,影响桥梁的使用舒适性。 3、以下挂式人行桥为研究对象,分别对在随机人群荷载及随机车流作用下,结构振动的概率分布特点及舒适性进行了研究；特别是在车流作用分析中,考虑了车过伸缩缝时的冲击效应,通过与试验结果对比,对伸缩缝冲击效应的模拟方法及其对结构舒适性的影响进行了研究；结果表明,这类人行桥的舒适性主要受伸缩缝冲击效应的影响。 4、以一分离式钢箱梁桥的振动声辐射预测及声环境评价为对象,通过与实测结果对比,验证了车桥耦合振动结合点声源法求解体系在预测振动声辐射上的有效性；在此基础上,对随机车流作用下,结构振动声辐射的声压分布特点进行了分析；并基于烦恼率,分别采用G声级和C声级对结构振动辐射的次声噪声和低频噪声进行了概率意义上的评价。结果表明：由桥面板局部振动引起的频率在10～20Hz之间的噪声为这类桥梁振动辐射噪声最主要的原因,通过降低路面粗糙度和提高桥面板刚度能有效实现减振降噪的目的。
[Abstract]:With the rapid increase in the traffic volume of people in China and the proximity of traffic space to human settlement space, traffic, The problems of comfort and noise caused by structural vibration are becoming more and more serious. In this paper, the problem of comfort caused by bridge vibration and the problem of radiated low frequency noise are taken as objects. In view of the shortcomings of the traditional deterministic method in the structural stress and the uncertainty of the human body's feeling, Based on the probabilistic method, a method for evaluating vibration comfort and sound environment is proposed, which can take into account the effects of random loads and individual differences at the same time. On the one hand, a system for calculating and analyzing the vibration response of structures under random crowd and vehicle flow loads is established. The probabilistic analysis of the structural response is realized. On the other hand, the probability distribution curves on vibration and noise are established considering the influence of individual sensory differences on the existing experimental results and standards. Thus the comprehensive objective evaluation of the structure under the influence of various random factors is realized. Through the application analysis of practical engineering, the work and main conclusions of this paper are as follows:. 1. An accurate method to simulate the vibration response of footbridge under walking load is developed. The accuracy and validity of the algorithm are tested by comparing with the results of field vibration test, and based on the vibration comfort evaluation method proposed in this paper, The comfortableness of structural vibration under random crowd load is studied systematically. The results show that the vibration uncomfortableness may also occur for the footbridge whose fundamental frequency is more than 3 Hz. 2. Taking the vibration response calculation and comfort evaluation of flexible cableway bridge under the action of step load as the object, a simple nonlinear vibration equation and algorithm for ropeway bridge are established. The validity of the algorithm is verified by comparing with the measured results of vibration. On the basis of this, the comfortableness of the structure under random crowd load is studied. The results show that the flexible cableway bridge is low in frequency because of the small stiffness of the structure. It is easy to take place step resonance at high-order mode frequency under the step load, which affects the comfort of the bridge. 3. The probabilistic distribution characteristics and comfortableness of structural vibration under the action of random crowd load and random traffic flow are studied respectively, especially in the analysis of vehicle flow, In this paper, the impact effect of over expansion joint is considered, and the simulation method of impact effect of expansion joint and its influence on structural comfort are studied by comparing with the test results, the results show that, The comfort of this type of footbridge is mainly affected by the impact effect of expansion joint. 4. The prediction of vibration sound radiation and the assessment of sound environment of a separated steel box girder bridge are taken as objects. By comparing with the measured results, the validity of the solution system of vehicle-bridge coupling vibration combination point method in predicting vibration sound radiation is verified. The characteristics of sound pressure distribution of structural vibration sound radiation under the action of random traffic flow are analyzed, and based on the vexation rate, The probabilistic evaluation of infrasound noise and low frequency noise emitted by structural vibration is carried out by using G and C sound levels respectively. The results show that the noise caused by the local vibration of the deck slab is a bridge with frequency between 10 and 20 Hz. The main cause of vibration radiation noise, The purpose of reducing vibration and reducing noise can be realized effectively by reducing road roughness and improving the stiffness of bridge deck.
【学位授予单位】：浙江大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：U441.3

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