高速铁路大跨钢桁梁斜拉桥梁端锚固结构疲劳性能研究

Fatigue performance of cable-to-girder connection of a long span high-speed railway cable-stayed bridge with steel truss

南京至安庆高速铁路线上主跨580 m的安庆长江大桥的梁端锚固结构采用一种新的双拉板栓焊式锚箱结构。对铁路钢桁梁斜拉桥几种典型梁端锚固结构的结构特点及传力机理进行比较分析。为评估高速行车条件下双拉板栓焊式梁端锚固结构的抗疲劳性能,对其进行疲劳试验研究。选取斜拉索活载索力幅值最大的梁端锚固结构为研究对象,利用ANSYS建立锚固结构有限元模型,分析得到主要焊缝应力分布。根据列车的运营情况,考虑4线列车通过桥梁时的相遇概率,运用Miner疲劳损伤累积准则,得到梁端锚固结构的疲劳内力幅。采用1∶2缩尺模型,完成梁端锚固结构模型疲劳试验。疲劳试验结果表明,安庆长江大桥所采用的双拉板栓焊式锚箱结构在其设计寿命期内不会发生疲劳开裂,疲劳性能满足设计要求。

With double-plate and anchor-box, a new bolt-welded cable-to-girder anchorage structure was used to connect cables with steel trusses of Anqing Yangtze Rive Railway Bridge for high-speed railway from Nanjing to Anqing. Typical anchorage structures used in steel trusses were introduced and their mechanical behaviors were investigated. In order to obtain the fatigue performance of a cable-to-girder connection bearing high-speed train load, its fatigue tests were conducted. The cable-to-girder connection bearing the maximum cable force with live load acting was taken as a study object. Using ANSYS, a 3D finite element analysis on it was performed and stress distributions on its main welds were obtained. The encountering probability of trains was taken into account. According to Miner fatigue accumulation damage rule, the fatigue load range of the cable-to-girder connection was determined. Using a specimen with a scale of 1:2, its fatigue test was conducted. Test results showed that no fatigue cracks appear on the cable-to-girder connection within the service life of the bridge, and the fatigue performance of the cable-to-girder connection of Anqing Yangtze River Railway Bridge can meet the requirements of design.