既有多跨混凝土连续梁桥的车辆荷载效应评估研究

发布时间：2018-03-31 18:33

  本文选题：既有桥梁　切入点：车辆荷载效应评估　出处：《福州大学》2014年硕士论文

【摘要】：车辆荷载是桥梁结构最重要的一类设计荷载。随着车辆超限超载现象日趋严峻,既有桥粱的安全性面临着巨大考验。本文以多跨混凝土连续梁桥——福州市鳌峰大桥为工程背景,为了能够完善地评估该桥的车辆荷载效应,保障桥梁结构的安全使用性能,科学合理地制定养护、加固等决策,本文进行了以下主要工作：(1)根据环境振动试验,以基于频率的单目标函数进行有限元模型修正,建立后续评估所需的基准有限元模型。(2)根据现有的交通调查资料,基于平衡更新随机过程计算特定车队通过桥梁的概率,结合车队总重的概率密度函数以及车队影响线面积最大值数据点集建立该桥的车辆荷载模型,得出正常运营状态与异常运营状态不同评估基准期的车辆荷载效应最大值概率分布,并与设计荷载作用下的效应值以及规范限值进行对比评估。(3)利用IBIS-S监测系统进行效应监测,将实测效应最大值的拟合概率密度函数及分布函数同上述理论概率密度函数及分布函数进行比较,验证车辆荷载模型的有效性。计算不同评估基准期实测效应的最大值分布情况,与设计效应进行比较评估,并与上述理论评估结果进行对比。研究结果表明：(1)基于频率的单目标函数可用于桥梁的有限元模型修正,修正后计算频率与实测频率能够得到很好的吻合,动力特性的理论计算成果得到很大的改善。(2)不同评估基准期内,车辆荷载效应最大值分布服从极值Ⅰ型分布,且效应最大值分布的0.95分位值未超过设计效应以及规范限值,桥梁在后续服役期间能满足正常使用状态变形要求。当考虑桥梁损伤与桥梁超载这两种异常运营状态时,在满足一定的损伤和超载条件下,0.95分位值将会超越设计效应,但始终能满足规范要求。(3)现有的监测数据表明,实测效应最大值分布为正态分布,且后续运营期间,能满足正常使用状态变形要求。同时结合理论计算与实测计算的尾部分布对比情况,认为采用平衡更新随机过程理论来获取效应尾部分位值有一定的合理性。
[Abstract]:Vehicle load is the most important type of design load for bridge structure. With the phenomenon of vehicle overloading becoming more and more severe, the safety of existing bridge beam is facing a great test. In this paper, the multi-span concrete continuous beam bridge-Fuzhou Aofeng Bridge is taken as the engineering background. In order to evaluate the vehicle load effect of the bridge, ensure the safe use performance of the bridge structure, and make scientific and reasonable maintenance and reinforcement decisions, the following main work is carried out in this paper: 1) according to the environmental vibration test, Based on the single objective function based on frequency, the finite element model is modified, and the benchmark finite element model for subsequent evaluation is established. (2) based on the existing traffic survey data, the probability of a specific motorcade passing through the bridge is calculated based on the stochastic process of equilibrium renewal. The vehicle load model of the bridge is established by combining the probability density function of the total weight of the vehicle fleet and the data set of the maximum area affected by the motorcade. The maximum probability distribution of vehicle load effect in different base periods of normal operation and abnormal operation is obtained, and compared with the effect value under the action of design load and the value of code limit, the IBIS-S monitoring system is used to monitor the effect. The fitting probability density function and distribution function of the measured maximum effect are compared with the theoretical probability density function and distribution function. The validity of the vehicle load model is verified. The maximum distribution of the measured effects in different evaluation reference periods is calculated and compared with the design effect. The results show that the single-objective function based on frequency can be used to modify the finite element model of the bridge, and the calculated frequency is in good agreement with the measured frequency. The theoretical calculation results of dynamic characteristics are greatly improved. (2) in different evaluation reference periods, the maximum distribution of vehicle load effect is distributed from extreme value to type 鈪，

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