随机车载下连续刚构桥动力可靠度分析

发布时间：2018-04-04 23:32

本文选题：斜拉桥　切入点：随机车流　出处：《中外公路》2017年05期

【摘要】：引入车流-桥梁耦合振动模型至桥梁结构可靠度分析中,提出了随机车流作用下大跨桥梁动力响应的简化分析方法,应用于桥梁动力位移极值外推与首超失效概率评估。基于中国某高速公路的动态称重数据,模拟了稀疏和密集状态的随机车流,建立了主跨为200m连续刚构桥梁的车载效应概率模型。工程实例分析结果表明:随机车流-桥梁耦合振动分析结果为时程曲线,可视为随机过程的一个样本,而Rice公式可捕捉到该曲线的概率特征,可用于研究考虑车流-桥梁耦合振动效应的极值外推;随着输入车流样本的增长,桥梁响应均值与标准差趋于稳定,随机车流作用下大跨桥梁的荷载效应满足平稳随机过程假定;连续刚构桥在密集车流作用下的关键失效点位于中跨跨中,当现有密集车流占有率由1.2%增大到3.6%时,该桥梁的位移首超可靠指标从5.76下降至5.60。
[Abstract]:In this paper, the vehicle-bridge coupling vibration model is introduced into the reliability analysis of bridge structure, and a simplified analysis method of dynamic response of long-span bridge under random vehicle flow is proposed, which is applied to the extrapolation of bridge dynamic displacement extremum and the evaluation of the first overfailure probability.Based on the dynamic weighing data of a freeway in China, the random traffic flow in sparse and dense state is simulated, and the probabilistic model of vehicle-borne effect of 200 m continuous rigid frame bridge with main span is established.The analysis results of engineering examples show that the time-course curve of random vehicle-bridge coupling vibration analysis can be regarded as a sample of random process, and the probability characteristic of the curve can be captured by Rice formula.It can be used to study the extreme extrapolation considering the vehicle-bridge coupling vibration effect, and the mean and standard deviation of the bridge response tend to be stable with the increase of the input vehicle flow sample.The load effect of long-span bridge under the action of random traffic flow satisfies the assumption of stationary stochastic process, and the key failure point of continuous rigid frame bridge under the action of dense traffic flow is located in the middle span of mid-span, when the occupancy rate of existing dense traffic flow increases from 1.2% to 3.6%,The superreliability index of the first displacement of the bridge was reduced from 5.76 to 5.60.
【作者单位】：株洲市规划设计院;宜宾市铁路建设有限责任公司;
【分类号】：U441.3;U448.23

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