锁死销对连续梁桥地震响应的影响

摘要

To understand the impact of the locking dowels on the longitudinal seismic perform‐ance of continuous girder bridge with different pier height ,the main bridge of the Yuanjiang River Bridge [a prestressed concrete continuous girder bridge with span arrangement (62 .5+5 × 96+62 . 5) m] on Shimen‐Changsha Double‐Track Railway was taken as an example and with reference to the working principles of the dowels ,the ANSYS was used to set up the finite element model for the whole bridge of the bridge with different pier height ,the seismic mitigation performance of the dowels and the impact of the parameters of the dowels on the seismic mitigation effect were ana‐lyzed .The results of the analysis show that the locking dowels arranged on the sliding piers can significantly improve the global seismic performance of the continuous girder bridge and the proper increase of the internal force responses of the sliding piers can effectively decrease the internal forces of the fixed piers and girder end displacement .The seismic mitigation effect of the dowels gradually decreases with the increase of the acceleration activating thresholds .At the time the ac‐celeration activating thresholds and locking clearances change ,the lower the sliding piers are ,the more significant the seismic response changing of the piers will be .It is therefore proposed that at‐tention should be paid to the protection of the low piers as the locking dowels are used for the seis‐mic mitigation of the continuous girder bridges with different pier height .%为了解锁死销对不同墩高的连续梁桥纵向抗震性能的影响，基于锁死销的工作原理，以石长铁路沅江特大桥主桥[（62．5＋5×96＋62．5） m预应力混凝土连续梁桥]为背景，采用A N‐SYS建立不同墩高的全桥有限元模型，分析了锁死销的减震性能及其参数对减震效果的影响。结果表明：在滑动墩上设置锁死销可显著提高连续梁桥的整体抗震性能，适度增加各滑动墩内力响应可有效降低固定墩的内力和梁端位移；减震效果随着加速度激活阀值的增大而逐步降低；加速度激活阀值和锁死间隙变化时，滑动墩墩高越矮，其地震响应变化越明显。建议采用锁死销装置对不同墩高的连续梁桥进行减震时应注意对矮墩的保护。