随机车流下悬索桥加劲梁动力响应概率模型与可靠度研究

发布时间：2018-01-19 04:22

本文关键词： 悬索桥加劲梁随机车流动力可靠度疲劳可靠度密集运行状态首超准则等效疲劳应力　出处：《长沙理工大学》2014年博士论文　论文类型：学位论文

【摘要】：公路桥梁在运营期承受大量车辆荷载的反复作用,随着车流量和载重量的增加,车载下既有桥梁在的安全问题日益突出。车流量、结构参数和失效模式等诸多因素的不确定性致使桥梁在运营期的安全性不免为概率问题。大跨度悬索桥的柔性加劲梁在车载下易出现位移超限失效和构造细节疲劳累积损伤失效,基于结构动力可靠度与疲劳可靠度理论可分别评估上述两种失效模式下的安全水平。本文结合国家“973”项目“特大跨桥梁安全性设计与评定的基础理论研究(2015CB057700)”和国家自然科学基金项目“车辆超载与氯盐侵蚀复合作用下钢筋砼梁桥的疲劳时变可靠度分析(51378081)”,主要研究基于高速公路桥梁WIM(动态称重)系统的随机车流模型,以及随机车流作用下悬索桥加劲梁的动力响应(位移和疲劳应力)的概率特征,围绕结构可靠度研究中的两个失效准则(首超破坏和疲劳破坏)研究全桥整体模型中的加劲梁位移首超动力可靠度和加劲梁局部模型中的焊接细节疲劳可靠度。具体研究内容有：(1)研究了基于WIM系统的随机车流模拟方法。建立了某高速公路车流的车型、轴重、车距、车速和车道等参数的概率模型,在MATLAB的GUI平台编制了随机车流模拟软件,分别生成了稀疏和密集运行状态下的随机车流样本,预测了交通量增长系数。(2)为了准确和快速得出车流荷载下大跨桥梁动力响应时程数据,提出了基于有限元的简化分析方法。以ANSYS通用有限元程序为平台,充分发挥其对车辆和桥梁的简化模拟能力以及瞬态分析的后处理功能,相关算例表明了该方法的可行性和准确性。(3)基于跨越理论建立了随机车流作用下悬索桥加劲梁的位移响应的极值概率模型。研究了车辆和车流参数对车载下悬索桥加劲梁位移响应的影响,统计数据表明随机车流下悬索桥位移响应为非严格高斯平稳随机过程,基于Rice公式预测了加劲梁在设计基准期内的位移极值。(4)基于位移首超准则评估了随机车流下悬索桥加劲梁的动力可靠度。讨论了Possion假定和Markov假定对界限跨越率的影响,揭示了车辆运行状态和加劲梁的参数变化对动力可靠指标的影响规律,参数分析表明主缆刚度退化和密集运行车辆是导致加劲梁位移首超失效的重要因素。(5)将典型疲劳车辆改进为随机车流模型,结合高斯混合模型建立了运营期内悬索桥钢箱梁关键细节疲劳应力和疲劳损伤概率模型。针对随机车流作用下有限分析的耗时过长问题,提出了基于UD-SVR(均匀设计-支向量回归)联合算法的随机车流下钢箱梁细节疲劳应力分析方法。(6)研究了考虑车流参数以及交通量和车重增长系数的钢箱梁桥关键焊接细节疲劳可靠度。建立了考虑随机车流参数的疲劳损伤功能函数,编制了结构疲劳可靠度分析软件,分析了交通量和车重增长对不同车道处焊接细节疲劳可靠度的影响,基于目标可靠指标评估了钢箱梁关键细节处疲劳性能。研究结果为基于车流辆监测数据的桥梁焊接细节疲劳可靠度与加固维修提供了依据。
[Abstract]:Road bridge in the repeated operation period bear a large number of vehicle load, with the traffic and load increases, vehicle existing safety problems in bridge has become increasingly prominent. The traffic flow, structure parameters and failure mode of many factors such as the uncertainty of the bridge in the safety operation period is inevitably probability problem. The flexible beam the long-span suspension bridge in vehicle is prone to failure and displacement gauge structure detail fatigue cumulative damage failure, structure dynamic reliability and fatigue reliability theory respectively to assess the safety water above two failure modes. Based on the level of the basic theory research of bridge design and evaluation of security, combined with the national "973" project "(2015CB057700) and the National Natural Science Fund Project" fatigue of reinforced concrete beam bridge under the combined action of erosion overloading and chloride time-varying reliability analysis (51378081) "Based on the highway bridge WIM (WIM) random traffic flow model of the system, and the dynamic stiffened suspension bridge under random traffic flow beam response (displacement and fatigue stress) probability characteristics, around two criteria failure of structural reliability in (the first super damage and fatigue damage) of super dynamic reliability the degree of local model and stiffening girder welding in the details of the fatigue reliability of the stiffening girder displacement model of bridge in the whole song. The specific research contents are as follows: (1) to study the random traffic simulation method based on WIM system. The establishment of a certain expressway traffic flow models, axle load, vehicle distance, speed and lane, probability model the parameters in the MATLAB GUI platform, developed the random traffic simulation software, which generates sparse and dense running under the random traffic sample, forecasts the traffic volume growth coefficient (2). In order to accurately and quickly get out of the bus Flow load of long span bridge under dynamic response time history data, a simplified finite element analysis method. Based on the ANSYS finite element program as a platform, give full play to the function of vehicle and Bridge simplified simulation capability and transient analysis, relevant examples show the feasibility and accuracy of this method. (3) established the extreme probability model of displacement response of suspension bridges under random traffic flow across theory. Based on research of vehicle and traffic flow parameters on the stiffened suspension bridge under vehicle beam displacement response, the statistics show that the displacement response of suspension bridge under random traffic flow for non strict Gauss stationary stochastic process, the Rice formula for predicting the displacement the stiffening beam in the design reference period (4). Based on the displacement of the first super criterion based on the assessment of the random traffic flow dynamic stiffening girder of suspension bridge reliability is discussed. The assumption of Possion and Markov Assume the crossing rate impact on the boundaries, reveals the influence of parameter changing the running state of the vehicle and the stiffening girder on the dynamic reliability index, the parameter analysis indicates that the main cable stiffness degradation and intensive operation of the vehicle is an important factor leading to the displacement of stiffening girder first passage failure. (5) the typical vehicle fatigue improvement for the random traffic flow model. The establishment of the operation period of suspension bridge key details of fatigue stress and fatigue damage probability model with the Gauss mixture model. According to the random traffic flow under the limited analysis of the time consuming problem, proposed based on UD-SVR (uniform design - support vector regression) stress analysis method of fatigue of Steel Box Girder Joint Algorithm under random traffic details (6. Considering the traffic parameters) and bridge traffic volume and weight growth coefficient of the key welding detail fatigue reliability. A fatigue damage function considering random traffic parameters To function, developed the structure fatigue reliability analysis software, analyzed the influence of traffic volume and weight growth on different lanes at weld detail fatigue reliability, target reliability index evaluation based on the fatigue performance of steel box girder key details. The results for the bridge based on vehicle traffic monitoring data of the fatigue reliability of the welded details and provides reinforcement and maintenance on the basis of.

【学位授予单位】：长沙理工大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：U441;U448.25

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