高速铁路大跨连续梁桥减震方案比较

Comparison of Vibration Reduction Schemes for Large-span Continuous Girder Bridge on High-speed Railway

以某高速铁路(60+100+60)m大跨连续梁桥为研究对象,引入阻尼器和速度锁定器(Lock-up)减震装置,通过有限元软件建立减震体系模型,采用非线性动力时程法研究分析两种减震装置、4种布置方案在不同墩高下结构内力的分布规律及减震效果。研究结果表明:(1)在10~40 m墩高内,阻尼器减震方案下墩底内力减震率随墩高增加而增大,整体布置方案下固定墩底减震率为37.1%~56.9%,较局部布置方案高出10%~18%;(2)Lock-up装置是以增大活动墩底内力来降低连续梁固定墩底内力的,且受墩高影响显著;(3)从各墩内力总和来看,阻尼器方案下各墩底内力总和减震率为17.1%~52.1%,而Lock-up方案仅当墩高大于30 m时各墩底内力总和才低于抗震体系;(4)对于墩高相对较矮的三跨铁路连续梁,阻尼器的减震效果明显优于Lock-up装置。

For a large-span(60+100+60)m continuous girder bridge on a high-speed railway as the object of this study,the dampers and lock-up devices were introduced for vibration reduction.Then a vibration reduction system model was established through finite element software,and the nonlinear dynamic time-history method was used to analyze the distribution patterns of structural internal forces under different pier heights and vibration reduction effects for the two vibration reduction devices and four deployment schemes.The study results show:(1)Within a pier height of 10~40 m,the vibration reduction rate of the base of the pier with dampers increases with the height of the pier.The vibration reduction rate of the fixed pier base under the overall layout scheme is 37.1%~56.9%,which is 10%~18%higher than that under the partial arrangement scheme.(2)The lock-up devices reduce the internal force of the fixed pier base at the expense of increasing the internal force of the active pier base,and it is significantly affected by the pier height.(3)From the perspective of the total internal force of each pier,the vibration reduction rate of the total internal force at the base of each pier with damper is 17.1%~52.1%,while the total internal force at the base of each pier with lock-up device only falls below the seismic system when the pier height is greater than 30 m.(4)For three-span continuous girder railway bridge with relatively low pier height,the damper has a noticeably better vibration reduction effect than the lock-up device.