轨道交通U梁温度梯度效应研究

Temperature Gradient Effect of U-Beam in Rail Transit

为研究轨道交通U梁的温度梯度效应,整理并总结目前国内既有项目对高架U梁进行的温度监测模式及研究结果,结合实体有限元模型计算分析,得出U梁在各温度梯度模式下的温度应力及变形值,并提出可应用于工程设计的U梁温度梯度模式。研究结果表明,温度梯度荷载工况下的U梁纵向正应力值在设计正应力值中占比相对较大,而横向应力和局部变形差相对较小;轨道交通线路走向大体呈东西向时,高架U梁运营后的腹板竖向温度梯度建议采用指数函数,底板竖向温度梯度建议采用折线函数,研究结果可为相关工程设计提供参考。

To study the temperature gradient effect of U-beam in rail transit,the temperature monitoring results of U-beam in existing domestic projects are collated and summarized along with the temperature load in the current railway code and conventional practice.The result,combined with solid finite element model calculations,is used to obtain the temperature stress and deformation of U-beam under different temperature gradient modes.The longitudinal normal stress value of the U-beam under the gradient temperature load condition accounts for a relatively large proportion of the normal stress value,whereas the contributions of transverse stress and local deformation difference are relatively small.Finally,a temperature gradient mode suitable for U-beam is proposed.When the trend of the rail transit line is roughly east-west,the vertical temperature gradient of the train network web is an exponential function,and the vertical temperature gradient of the bottom plate is a broken line function.This conclusion can serve as a reference for relevant engineering design.