大跨度公轨两用斜拉桥梁端轨道结构适应性研究

Adaptability of Ballastless Track Structures Laid on Girder-end of Long-span Rail-cum-road Cable-stayed Bridge

为研究大跨度桥梁端无砟轨道结构的适应性问题,以一座大跨度公轨两用斜拉桥为例,针对其大转角、大梁缝及长悬臂的特点,提出梁端采用过渡板与梯形轨枕两种特殊轨道结构措施,探讨不同措施对扣件受力的影响。结果表明,过渡板支座若按常规方法置于桥梁支座上方,则难以在梁端大转角情况下将扣件上拔力控制在安全范围内,合理调整过渡板支座往桥梁支座内侧延伸长度,可增强其对梁端大转角的适应性;梯形轨枕纵梁两端是否设减振垫以及至桥梁梁端距离大小对扣件受力有较大影响,参考研究结果选择适当布置方式,可使梯形轨枕对大转角、大梁缝及长悬臂桥梁具有良好适应性。

To investigate the adaptability of ballastless tracks laid on the girder-end of long-span bridges, in response to the large girder-end rotation angle, considerable expansion joint width and long cantilever of a rail-cum-road cable-stayed bridge,two special track structure measures, approach slab and ladder sleeper, were proposed. Moreover, extensive numerical experiments were conducted to analyze the force of fasteners under the two strategies. The results show that if the bearings of approach slab are placed right above the bridge bearings, according to the conventional method, it is difficult to control uplift force of fasteners within limitation when the bridge has great girder-end rotation angle. The adaptability of the approach slab to large girder-end rotation angle can be improved by reasonable adjustment of the distance between the approach slab bearings and the bridge bearings. In the case of laying ladder sleeper on girder-end of the bridge, it is found that the force of fasteners is greatly affected by whether there are supporting pads located at the ends of ladder sleeper stringer as well as the distance between the ladder sleeper stringer end and the bridge girder-end. Therefore, optimal arrangements of the ladder sleeper stringer under various circumstances are suggested so as to enable ladder sleepers to achieve favorable adaptability to long-span bridges with typical characteristics of large girder-end rotation angle, considerable expansion joint width and long cantilever.