随机车载下钢筋混凝土桥面板疲劳寿命分析方法研究

发布时间：2018-03-05 02:35

  本文选题：RC桥面板　切入点：随机车流　出处：《哈尔滨工业大学》2016年硕士论文　论文类型：学位论文

【摘要】：随着中国经济快速稳定的增长,中国公路承载的交通量迅猛增加,超载问题日益突出,导致车辆荷载作用下公路混凝土桥梁出现了大量的疲劳问题。在以往的桥梁结构设计中,主要是以承载能力作为桥梁结构安全的控制指标,轻视了在反复荷载作用桥梁结构的耐久性指标。工程实践表明运营条件下直接承受车辆荷载作用的混凝土桥面板最易发生疲劳损伤和破坏,从而影响桥梁结构整体的使用性能。为此,本文以混凝土桥面板为对象,开展随机车辆荷载作用下混凝土桥面板的疲劳寿命分析方法研究。首先,编制方程维度时变的随机车流与桥梁耦合振动分析程序算法。依据某公路的实际交通量观测和调查数据,将该公路上的车辆类型归纳整理,建立了典型车辆荷载库,确定了交通量统计中的主要参数,如车型比例、车辆间距和车辆轴重等所服从的概率分布,模拟生成随机交通流。采用拉格朗日原理,构建了典型车辆的运动方程。选取公路中常见简支转连续装配式预应力钢筋混凝土T梁桥,建立了其ANSYS有限元模型并进行模态分析。依托算例,分析了车辆类型、车速和桥面不平整度状况对车载下桥梁结构动力冲击效应的影响,并与规范计算结果进行了对比。然后,建立基于连续损伤力学的RC桥面板疲劳寿命分析预测模型和分析方法。研究了钢筋混凝土疲劳损伤机理,分析指出了控制桥面板疲劳破坏的主要因素。对比分析了线性疲劳损伤累积理论和非线性疲劳损伤累积理论的特点和各自优劣势。依托算例,计算得到了随机车载下桥面板疲劳热点位置的动应力时程,运用雨流计数法得到应力幅和平均应力,应用两种不同的疲劳损伤模型对桥面板进行了疲劳寿命预测分析。最后,研究了交通量增长、车辆超载和桥面状况劣化等因素对桥面板疲劳损伤的影响。采用灰色模型构建了交通量增长模型,分析了不同交通量下桥面板应力幅的变化规律和在固定时间节点改变交通量对桥面板疲劳寿命造成的影响。依据我国各主要公路的超载现状调查数据,指出各车辆类型的超载比例和超载率。提出含有超载车辆的随机车流的模拟方法,分析在该车队作用下桥面板应力幅的变化规律。分析了含有超载车辆的随机车流作用在桥梁结构使用寿命的初期和中期,对桥面板疲劳寿命的影响。调查研究桥面状况的劣化规律,按照模拟的桥面状况分析在随机车载作用下疲劳热点应力幅的改变和预测实际桥面状况下桥面板的疲劳寿命。
[Abstract]:With the rapid and steady growth of Chinese economy, the traffic volume of Chinese highway is increasing rapidly, and the problem of overloading is becoming more and more serious, which leads to a lot of fatigue problems of highway concrete bridges under vehicle load. The load-bearing capacity is mainly used as the control index of bridge structure safety. The durability index of bridge structure subjected to repeated loads is despised. Engineering practice shows that concrete deck slabs directly subjected to vehicle loads are most likely to suffer fatigue damage and failure under operating conditions. Therefore, this paper studies the fatigue life analysis method of concrete deck slab under random vehicle load. Based on the actual traffic volume observation and investigation data of a highway, the vehicle types on the highway are summarized and sorted, and the typical vehicle load library is established. The main parameters of traffic statistics, such as the probability distribution of vehicle model ratio, vehicle spacing and vehicle axle load, are determined, and the random traffic flow is simulated. The Lagrangian principle is used. The equations of motion of typical vehicles are constructed. The ANSYS finite element model is established and the modal analysis is carried out by selecting the common simply supported and continuously assembled prestressed reinforced concrete T-beam bridges. Based on the example, the types of vehicles are analyzed. The effect of vehicle speed and bridge deck irregularity on the dynamic impact effect of bridge structure under vehicle is compared with the calculated results of the code. The fatigue life prediction model and method of RC bridge slab based on continuous damage mechanics are established. The fatigue damage mechanism of reinforced concrete is studied. The main factors controlling the fatigue failure of bridge deck are analyzed. The characteristics and advantages and disadvantages of linear fatigue damage accumulation theory and nonlinear fatigue damage accumulation theory are compared. In this paper, the dynamic stress time history of the fatigue hot spot of the deck slab under random vehicle is calculated, the stress amplitude and mean stress are obtained by the rain flow counting method, and the fatigue life of the bridge deck is predicted by two different fatigue damage models. Finally, the fatigue life of the bridge deck is predicted and analyzed. The effects of traffic volume growth, overloading of vehicles and deterioration of deck condition on fatigue damage of bridge deck are studied. A traffic volume growth model is constructed by using grey model. The variation law of bridge deck stress amplitude under different traffic volume and the influence of changing traffic volume at fixed time node on the fatigue life of bridge deck slab are analyzed. According to the investigation data of overloading status of major highways in China, the influence of the change of traffic volume on the fatigue life of bridge deck slab is analyzed. The overloading ratio and overloading rate of each type of vehicle are pointed out, and the simulation method of random vehicle flow with overloaded vehicle is presented. The variation law of the stress amplitude of the deck slab under the action of the motorcade is analyzed. The effect of random vehicle flow with overloaded vehicles on the initial and middle life of the bridge structure is analyzed. According to the simulated bridge deck condition, the change of the stress amplitude of fatigue hot spot under the action of random vehicle and the prediction of the fatigue life of the bridge deck under the actual bridge deck condition are analyzed.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：U441.4
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本文编号：1568407