桥墩温差荷载引起的桥上无缝线路钢轨附加力

Additional Longitudinal Force of CWR Track on Bridge Caused by Temperature Difference between One Side and Another Side of Pier

采用单位荷载法计算桥墩温差荷载引起的墩顶纵向位移。根据梁轨相互作用原理,建立“轨—梁—墩”有限元模型,计算桥墩温差引起的桥上无缝线路钢轨附加力,研究桥墩温差引起的钢轨附加力的分布规律及其影响因素。研究表明:多跨简支梁桥墩温差引起的钢轨附加力的最大压力出现在右桥台处,最大拉力出现在靠近左桥台的边墩处,离桥台越远,钢轨附加力越小;随着墩高的增加,桥墩温差引起的钢轨附加力增大,建议在设计高墩桥上无缝线路时,应考虑桥墩温差引起的钢轨附加力,并与其他钢轨附加力叠加检算钢轨强度和无缝线路稳定性;桥墩温差引起的钢轨附加力,随着桥墩纵向水平线刚度的增加先快速增大,到一定程度后变缓;桥梁跨度对桥墩温差引起的钢轨附加力影响很小;钢轨附加力随着简支梁跨数的增加而增大,但逐渐变缓,当简支梁跨数超过18跨以后,钢轨附加力不再增长。

The longitudinal displacement of pier top caused by temperature difference between one side and another side of pier is calculated by unit load method. According to the principle of beam-rail interaction, a rail-beam-pier finite element model is built. The additional longitudinal rail force of CWR track on bridge caused by temperature difference is computed, and the distribution and the influencing factors of additional longitudinal rail force are analyzed. Research indicates that, for multi-span simple supported beam bridge, the maximum stress of the additional rail force caused by temperature difference between one side and another side of pier occurs on the right abutment. The maximum tension occurs at the side pier near the left abutment. The farther to the abutment, the less is the additional rail force. With the increase of pier height, the longitudinal additional force becomes greater. For CWR＇s design on high pier bridge, longitudinal additional force caused by temperature should be added to other additional force to check the rail strength and CWR＇s stability. With the increase of pier longitudinal stiffness, the longitudinal additional force becomes larger firstly, and then it makes steady after arriving at a certain extent. Span has little influence on the longitudinal additional force. Longitudinal additional force becomes larger when the amount of bridge span increases, and then it slows down. When the amount of bridge span is greater than 18, the longitudinal additional force becomes steady.