市域铁路曲线半径与桥梁最大温度跨度关系分析

Analysis of City Railway Curve Radius and Bridge Maximum Temperature Span Relationship

市域铁路小半径曲线大跨度连续梁地段,易产生桥上无缝线路检算不通过的问题。而钢轨伸缩调节器作为轨道结构薄弱环节,因其铺设条件严苛及自身问题,设计时较少考虑。在不设置钢轨伸缩调节器的原则基础上,采用有限元方法建立“线桥墩一体化”计算模型,对线路曲线半径与桥梁最大温度跨度关系进行分析探讨。结果表明:桥梁温度跨度与钢轨总应力呈一定的线性关系,可采用公式L=kσ+b来拟合表达;正线平面最小曲线半径R=350 m地段,计算得到的桥梁最大温度跨度值为132.9 m;曲线半径越小,允许的桥梁最大温度跨度值也越小。计算得到各级小半径曲线工况下对应的桥梁最大温度跨度值,在桥梁与轨道专业协同设计中,连续梁主跨与边跨设计取值建议参考对应的限值进行。

In sections of city railway with small radius curve and large-span continuous beam,issues may arise regarding the seamless line checking calculation on bridges.The rail expansion joint,as a vulnerable component of the track structure,is often overlooked in design due to its stringent laying conditions and inherent problems.Based on the principle of leaving out rail expansion joints,a'line-bridge pier integration'computational model is established using the finite element method to analyze and explore the relationship between the curve radius of the track and the maximum temperature span of the bridge.The research results are as follows:the bridge temperature span exhibits a linear relationship with the total rail stress and can be fitted and expressed by the formula L=kσ+b.In the segment with the smallest mainline horizontal curve radius of R=350 m,the calculated maximum temperature span for the bridge is 132.9 m.The smaller the curve radius is,the smaller the allowable bridge maximum temperature span will be.Bridge maximum temperature span values corresponding to working conditions of various levels of small radius curve are obtained from calculation.In the co-design of bridges and tracks,design values for the main span and side span of continuous beams are recommended to carry out in reference to respective limit values.