摘要
营运状况下漂浮体系悬索桥加劲梁纵向运动产生的过大累积行程会引起伸缩缝和塔梁纵向阻尼器等连接构件的性能退化和疲劳损坏。探索加劲梁纵向运动过大累积行程的成因,并找出降低累积行程的控制措施是确保悬索桥健康运营的关键。首先,以江阴长江大桥实测位移时程数据为基础,对不同频谱特性的位移成分进行分解,并统计了不同位移成分的循环次数和累积行程等特性,结果显示超低频位移成分贡献了绝大部分的累计行程。然后,以有限元模型为基础分析了拟静态纵向运动的成因,并反演得到了导致该类运动的等效竖向集中力时程曲线。最后,基于等效竖向集中力时程曲线研究了拟静态纵向运动的控制措施。结果表明:悬索桥加劲梁纵向位移根据成因可以分为温度变化引起的伸缩变形,拟静态纵向运动和低频共振纵向振动3种不同频谱特性的成分,其中拟静态纵向运动在累积行程中占比超过70%,进行纵向运动控制时不能忽略其影响;加劲梁的拟静态纵向运动的产生与加劲梁上反对称分布的竖向车辆荷载有关,不平衡竖向车辆荷载在桥面上移动完加劲梁整个长度完成一个纵向运动完整循环,这个机制是超低频运动产生的根本原因;基于拟静态纵向运动的产生机理,反演得到等效竖向集中力,可以有效还原实测分解得到的拟静态纵向运动,能够方便地评估各类控制装置对拟静态纵向运动的控制效果;用速度型阻尼器与摩擦阻尼器组合的方式,可以有效的抑制加劲梁的拟静态纵向运动。
The excessive cumulative longitudinal movement stroke of stiffening girders of floating-type suspension bridges under operation condition will lead to performance degradation and fatigue damage of connecting components such as expansion joints and longitudinal dampers between tower and girders. The key to ensure the normal and safe operation of suspension bridge is to explore the causes of excessive cumulative longitudinal movement stroke of stiffening girders and find out the control measures to reduce them. Firstly,based on the measured displacement time history data of Jiangyin Yangtze River Bridge,the displacement components with different spectral characteristics were decomposed,and the cycle numbers and cumulative stroke of different displacement components were calculated. The results show that the quasi-static displacement components contribute most of the cumulative stroke. Then,based on the finite element model,the cause of quasi-static longitudinal motion was analyzed,and the time history of equivalent vertical concentrated force was obtained by curve fitting. Finally,based on the time history of equivalent vertical concentrated force,the control measures of quasi-static longitudinal motion were studied. Results show that the longitudinal displacement of stiffening girder in suspension bridge can be divided into three different components according to the causes and spectrum characteristics:temperature change induced elongation and shortening deformation,quasi-static longitudinal motion and the longitudinal resonance. The quasistatic longitudinal motion contributes more than 70% of cumulative stroke,thus the longitudinal motion control can’t ignore its influence. The generation of quasi-static longitudinal motion of the stiffening girder is related to the unbalanced vertical concentrated force brought by the vehicle load. The unbalanced vertical concentrated force moves on the bridge deck for the whole length of the stiffening girder and completes a complete longitudinal motion cycle. This mechanism is the fundamental reason for the generation of quasi-static motion. Based on the generation mechanism of quasi-static longitudinal motion,the equivalent vertical concentrated force can be obtained by curve fitting,which can effectively reconstruct decomposed quasi-static longitudinal displacement. The equivalent vertical concentrated force can be used to conveniently evaluate the control performance of various control devices on quasi-static longitudinal motion. The combination of velocity-dependent damper and friction damper can effectively suppress the quasi-static longitudinal motion of stiffening girders.
作者
梁龙腾
封周权
陈政清
牛华伟
华旭刚
LIANG Longteng;FENG Zhouquan;CHEN Zhengqing;NIU Huawei;HUA Xugang(Key Laboratory of Wind and Bridge Engineering of Hunan Province,Hunan University,Changsha 410082,China;State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body,Hunan University,Changsha 410082,China;Guangdong Communication Planning and Design Institute Group Co.,Ltd.,Guangzhou 510507,China;Chongqing Research Institute of Hunan University,Chongqing 401133,China)
出处
《地震工程与工程振动》
CSCD
北大核心
2022年第1期110-121,共12页
Earthquake Engineering and Engineering Dynamics
基金
国家自然科学基金项目(52178284,51708203)
湖南省自然科学基金项目(2021JJ30106)。
关键词
漂浮体系悬索桥
拟静态纵向运动
累积行程
振动控制
阻尼器参数
floating-type suspension bridges
quasi-static longitudinal motion
cumulative stroke
vibration control
damper parameters
