连续梁桥锁死销减震机理及影响参数研究

DAMPING MECHANISM AND EFFECT PARAMETERS ANALYSIS OF LOCKING DOWEL FOR CONTINUOUS BRIDGES

连续梁桥为满足温度荷载引起的变形需求,一般只设一个固定墩,这致使在地震作用下上部结构的纵向地震荷载只由固定墩承担,这极易引起固定墩和伸缩缝破坏,甚至造成引桥落梁。针对这一问题,提出利用滑动墩的抗震潜能,协同固定墩共同承受地震作用的思想,研发了一种以地震动加速度激活的锁死销装置,通过在墩梁间设置锁死销实现在地震时限制滑动墩和梁体的相对位移,使滑动墩和固定墩协同受力,减小结构的整体地震响应,并以具体工程为例,分析了锁死销的减震原理及其参数对减震效果的影响。研究表明,在滑动墩上设置锁死销可以有效地减小固定墩和梁体的纵向地震响应,明显提高连续梁桥的整体抗震性能;其减震效果受锁死销加速度激活阀值和锁死间隙等参数影响较大。

In order to meet the demand of temperature deformation, generally only one fixed-pier is set in a continuous bridge. As a result, unfortunately, all the longitudinal seismic loads are applied to one fixed pier, which may result in the damage of the fixed pier and the expansion joint, and even lead to a falling-off. For this reason, an acceleration activating locking dowel is developed. The device is designed to be installed between the piers and beams, which can prohibit the relative displacement between the sliding piers and the bridge once the earthquake occurs and help the piers to collaboratively bear the longitudinal seismic force,thus reduce the seismic response. Meanwhile, a case study of a practical project is conducted to illustrate the damping effect of the locking dowel and its influence factors. According to the research results, the locking dowel can significantly reduce the seismic actions on the fixed pier and the relatively displacement between the sliding piers and the bridge, and thus improve the seismic performance of a continuous bridge. Besides, the damping effect of the device is mainly determined by the acceleration activating threshold and locking clearance.