抑制斜拉桥施工阶段风致振动的水阻尼器可行性研究  

Water-damper for wind-induced vibration control of a cable-stayed bridge in its construction stage

作　　者：李宇[1] 潘彪[1] 李琛[2] 汪洁[3] 高亮[4] 

机构地区：[1]长安大学,公路学院,旧桥检测与加固技术交通行业重点试验室,西安710064 [2]长安大学建筑学院,西安710064 [3]西安建筑科技大学土木工程学院,西安710055 [4]西安理工大学土木建筑工程学院,西安710048

出　　处：《振动与冲击》2016年第15期7-15,共9页Journal of Vibration and Shock

基　　金：国家自然科学基金(51408042);陕西省自然科学基础研究基金面上项目(2015JM5156);陕西省教育厅专项科研项目(15JK1422);西安市建设科技项目(SJW2014012);中央高校基本科研业务费专项资金项目(0009-2014G1211006)

摘　　要：相对于成桥状态,斜拉桥最大双悬臂施工阶段的刚度低、阻尼小,更容易产生风致振动。建议了一种安装拆卸方便、成本较低的水阻尼器,并进行了CFD仿真分析和减振试验,以验证其抑制斜拉桥施工期风致振动的有效性。结果表明:1水阻尼器能显著增大阻尼系数,减轻结构振动;2过小的开孔率不能有效利用水阻尼器内部流体的黏滞作用来耗能,而过大的开孔率则使得水阻尼器上下游两个表面压力差减小严重;3在靠近水阻尼器两侧位置开孔,会使得外部绕流的旋涡在其两侧脱落;而靠近中心位置的开孔则可以使大漩涡在其下游面上脱落,有利于增大阻力系数;4侧孔对系统阻尼的影响将会随水阻尼器上下游两面开孔的不同而改变,过大或过小的侧面开孔都会显著降低阻尼系数;5水阻尼器体积的增大会降低减振效果,同时还应合理设计水阻尼器的最优的孔隙率,以达到最佳减振效果。综上所述,水阻尼器能有效抑制结构振动,且成本低廉、施工方便,特别适用于某些只需在施工期进行短期风振控制的桥梁。As opposed to a finished cable-stayed bridge,wind-induced vibration can more easily be caused in max double-cantilever construction stage of a cable-stayed bridge because of its low stiffness and damping.Here,water-damper was suggested with its convenience and low cost.CFD Analysis and vibration reduction tests were carried on to study its effectiveness of vibration control.The results showed that①the system damping increases significantly by applying water-damper with holes,the structural vibration can be reduced effectively;② the effectiveness of water-damper drops with lower or higher opening hole rate;③if holes are opened at the edge of a water-damper,external flow vortices fall off;if holes are opened in the middle of a water-damper,the system damping increases;④ the effects of holes in sides of a water-damper on the system damping vary with different positions of holes,the system damping decreases significantly with lower or higher opening hole rate of sides;⑤ the effectiveness of water-damper drops with increase in its volume;the optimal opening hole rate should be designed to achieve the best effect of vibration reduction.It was shown that the wind-induced vibration can be controlled effectively by applying a water-damper with low cost and convenience,it is especially suitable for controlling wind-induced vibration of a cable-stayed bridge in its construction stage.

关 键 词：斜拉桥 最大双悬臂施工 水阻尼器 风致振动 减振耗能 

分 类 号：U448.27[建筑科学—桥梁与隧道工程]