以黄冈公铁两用大桥2015年前3季度主梁竖向挠度和温度的监测数据为对象,研究公铁两用斜拉桥主梁竖向挠度在温度、列车荷载和汽车荷载下的变化规律,重点讨论温度挠度与主梁的相关性、温度挠度的空间相关性以及列车挠度的概率统计特性。分析结果表明:1)温度挠度与主梁温度之间存在较强的线性相关性。边跨跨中、主跨1/4跨、主跨跨中和主跨3/4跨随着温度升高呈下挠趋势;相应地,辅助跨跨中随着温度升高呈上拱趋势;2)辅助跨跨中、主跨1/4跨、主跨3/4跨与主跨跨中的温度挠度具有较强的空间线性相关性。辅助跨跨中挠度与主跨跨中挠度变化趋势相反,主跨1/4跨和主跨3/4跨的挠度与主跨跨中挠度变化趋势相同;3)列车挠度与主梁温度之间没有明显的相关性,可以采用tLocation-Scale分布函数描述列车挠度实测数据的概率密度统计特性。
This paper analyzed the variation of girder vertical deflection of a highway-railway cable-stayed bridge based on the monitoring data of vertical deflection and temperature from the structural monitoring system of the Huanggang Highway and Railway Transit Yangtze River Bridge in the first three quarters in 2015. The vertical deflections of bridge girder influenced by temperature action, train action and traffic loadings were investigated including the correlation between thermal induced deflection and temperature, the spatial correlation between thermal induced deflections and statistical characteristics of train-induced deflections. The results indicate that: 1) The thermal induced deflection of bridge girder show obvious correlation with temperature.The deflections at the middle of side span, the middle of main span as well as the 1/4 point and 3/4 point of main span tend to be downward with the increasing of temperature. On the contrary, the deflection at the middle of assistant span tends to be upward with the increase of the temperature. 2) The thermal induced deflections at different points along the girder, including the middle of assistant span, the 1/4 point of main span, the 3/4 point of main span and the mi ddle of main span, have obvious spatial linear correlation with their position. The varying trend of deflection at the middle of assistant span is opposite to (that) at the middle of main span. The deflections at the 1/4 point of main span, the 3/4 point of main span and the middle of main span have a same varying trend. 3) The train-induced deflections and the girder temperature have no obvious correlation. Moreover, the statistical characteristics of probability density of train-induced deflections can be fitted by the T Location-Scale distribution function.