后加预应力拉索加固铁路桥梁的力学性能研究

Mechanical Properties of the Railway Bridge Strengthened with After-prestressing Cables

研究目的:针对铁路桥梁横向刚度不足的问题,提出一种后加预应力拉索快速加固铁路桥梁的方法。该方法不影响列车的正常运行,可以明显缩短加固施工周期,减小运输损失,保障整条线路的安全运营。本文主要研究拉索布置位置、拉索初应力、拉索布置角度对铁路桥梁动力性能的影响,并给出相应的工程建议值。研究结论:(1)布置的拉索层数越多,桥墩横向一阶频率提高得越多;拉索应优先布置在墩顶到距墩顶1/3墩高范围内;(2)拉索索力不宜过大,保证拉索绷紧即可;(3)当拉索与墩体角度达到50°时,桥墩横向一阶频率达到最大值,为便于施工,可把拉索都固定于同侧较长拉索的地面锚固系统,较长拉索与墩体成45°时加固效果较好;(4)实际工程应用时,应根据桥墩具体特征确定拉索的布置方案;(5)该研究结论可用于铁路桥梁桥墩横向振幅超限加固。

Research purposes： To restraint the transverse vibration of the deficient bridges, a potential retrofit measure named afterprestressing cables retrofit method for the railway bridge is proposed in this paper. This method does not affect the normal operation of the train, so it can significantly shorten the construction period, reduce the loss of transport, and guarantee the safe operation of the railway lines. In this paper, theory for this method is explained in detail, the influences of various modeling parameters, such as the location of the cable, the initial value for prestressing and the inclination angle of the cable are numerically assessed. Based on the analytical results, some proposal values for the aforementioned parameters are provided for their application to practical problems. Research conclusions： （ 1 ） The more layers of cable arranged, the more first - order frequency of lateral pier increased ; cables should be arranged between the top of the pier and top 1/3 in the high range. （2） The force of cables should not be too large, just ensure cables have tension. （3） When the cables angle with the pier body reaches 50 degrees, the first - order frequency of pier reaches the maximum value. In order to facilitate the construction, the cables should be fixed on the ground anchorage system which side existing longer cable. （4） The cables shall be determined by features which associates to the pier in the practical engineering application. （5） The research results can be used for railway bridge piers reinforcement about transverse amplitude .