芜湖长江大桥挠度预警阈值研究

Research on Deflection Early⁃warning Threshold of Wuhu Yantze River Bridge

为科学设定桥梁结构主梁挠度预警阈值,以芜湖长江大桥健康监测系统为背景,首先分离环境温度及列车荷载作用下的挠度数据,然后分时段建立环境温度与对应非过车挠度的相关性模型并统计过车时段挠度变化幅值,最后基于相关性模型及统计分析结果为主梁挠度设定预警阈值。研究结果表明:主梁挠度主要由环境温度及列车荷载产生,环境温度与挠度存在显著线性相关关系。2018年由列车引起的跨中挠度变化幅值最大值为253.31 mm,客运、货运列车引起的跨中挠度变化幅值分别集中在[40.72,43.20],[115.10,117,60]mm。结合各个时段相关性模型可将95%保证率的下分位线值与全年列车过桥时挠度变化幅值最大值之和设定为挠度动态预警阈值。

In order to set the deflection early-warning threshold of bridge girder scientifically,based on the health monitoring system of Wuhu Yangtze River Bridge,firstly,the deflection data under the action of ambient temperature and train load were separated,and then the correlation model between ambient temperature and corresponding nonpassing deflection was established in different periods,and the deflection variation amplitude during passing period was counted.Finally,based on the correlation model and statistical analysis results,the early-warning threshold was set for the girder deflection.The results show that the main girder deflection is mainly caused by ambient temperature and train load,and there is a significant linear correlation between ambient temperature and deflection.In 2018,the maximum variation amplitude of mid-span deflection caused by trains is 253.31 mm,and the variation amplitude of mid-span deflection caused by passenger and freight trains is concentrated in[40.72,43.20],[115.10,117.60]mm,respectively.Combined with the correlation model of each period,the dynamic deflection early-warning threshold can be set by the sum of the lower quantile line value of 95%guarantee rate and the maximum deflection variation amplitude of train passing the bridge in the whole year.