大跨度铁路斜拉桥换索方案设计与受力性能分析

由于斜拉索安全性病害和功能退化,斜拉桥在运营一定年限后需进行拉索更换。以某大跨双线铁路斜拉桥为工程背景,提出一种适用于铁路斜拉桥的斜拉索更换方案,该方案仅对出现病害的单根拉索进行拆除更换,无需中断桥上铁路行车。基于空间非线性有限元手段,计算拉索更换所致结构效应。结果表明,拉索更换会引起轻微的主梁线形不平顺和结构竖向刚度降低,桥面列车需作限速通行要求,换索状态下,桥梁各构件受力均满足规范要求,本文提出的换索方案是安全可行的。结合计算结果,针对换索方案的拉索张拉工艺和施工条件提出建议,以保证换索施工全过程的桥梁受力合理性。

Design and Stress Analysis of Cable Replacement for Long Span Cable-stayed Railway Bridge

Because of the security insufficiency and functional degradation of stay cables,the cables of cable-stayed bridge should be replaced after a certain period of service. Based on a large span double track cable-stayed railway bridge,a cable replacement approach is proposed for a single defected cable replaced without traffic interruption. A three dimensional nonlinear finite element method is introduced to calculate the structure effect caused by the replacement. The result shows that every component of the bridge meets the requirement of the codes on cable replacement,and the proposed method is safe and feasible. Cable tensioning procedures and working conditions for cable replacement are put forward to ensure structural rationality of the bridge during the entire process of cable replacement