大跨协作体系桥梁吊跨比对主梁涡振性能的影响  

Influences of hanging-span rations on the vortex-induced vibration performance of the main girder in large-span collaborative system bridges

作　　者：游衡锐 遆子龙 李永乐[1] 杨凌 潘俊志 YOU Hengrui;TI Zilong;LI Yongle;YANG Ling;PAN Junzhi(State Key Lab of Bridge Intelligent and Green Construction(Southwest Jiaotong University),Chengdu 611756,China)

机构地区：[1]桥梁智能与绿色建造全国重点实验室(西南交通大学),成都611756

出　　处：《哈尔滨工业大学学报》2024年第11期72-79,共8页Journal of Harbin Institute of Technology

基　　金：国家自然科学基金(52008349);中国博士后科学基金特别资助(2021T140573);四川省自然科学基金青年项目(22NSFSC0857)。

摘　　要：为研究斜拉-悬索协作体系中不同吊跨比对主梁涡振性能的影响,以某斜拉-悬索协作体系桥梁为工程背景,首先,开展了节段模型风洞试验,采用增长共振法获取桥梁断面涡激振动过程中的发展时程与稳态振幅;其次,基于考虑跨向振幅依存性的非线性涡激力模型,对节段模型振动位移时程进行希尔伯特变换识别得到主梁截面的气动阻尼随无量纲振幅变化的关系曲线;最后,计算了8种不同吊跨比备选方案的主梁涡振振幅,明确了大桥从斜拉体系逐渐过渡到悬索体系时主梁涡振的变化规律,提出了一种综合考虑涡振幅值和跨向影响范围的辅助性指标对结果进行评价和对比。结果表明:随着吊跨比增加,基频降低,对应的1阶竖弯模态振型不断变宽;随着吊跨比的增加,跨中涡振幅值不断减小,不同吊跨比下跨中涡振幅值差异约11.1%,同时主梁起振风速有所下降;结合主梁涡振幅值指标η^(*)和主梁加速度指标a^(*)对不同吊跨比下大桥的涡振程度进行综合比较,发现随着吊跨比的增加,虽然跨中涡振幅值不断减小,但主梁的涡振影响范围不断加宽,主梁整体涡振程度显著增加,不同吊跨比下η^(*)差异约59.5%。吊跨比对主梁平均加速度a^(*)影响有限。In order to study the influence of different suspension-span ratios on the vortex-induced vibration performance of the beam in the cable-stayed-suspension cooperative system,a bridge with a cable-stayed-suspension cooperative system is used as the engineering background.Firstly,based on wind tunnel test,the method of Growth-to-resonance is used to obtain the development time history of the bridge section,which is in the process of VIV.Secondly,based on the nonlinear vortex-induced force model considering the span-direction amplitude dependence,the relationship curve of the aerodynamic damping parameters of the main girder section with the dimensionless amplitude is obtained through Hilbert transform.Finally,through iterative calculation of the beam VIV amplitude of eight alternatives.The change law of VIV in the processing of changing from the near-cable-stayed system to the suspension-cable system is clarified and a new evaluation index is proposed that considers the VIV amplitude value and the span-direction influence range.The results show that:with the increase of the hanging-span ratios,the corresponding first-order vertical bending mode shape changes from sharp to flat and the fundamental frequency decreases.As the hanging-span ratios increases,the vortex-induced vibration amplitude at mid-span consistently decreases.The variation in mid-span vortex vibration amplitude across different hanging-span ratios is approximately 11.1%.Additionally,the onset wind speed for the main girder′s vibration decreases with increasing hanging-span ratios.Combined with the average VIV amplitude value of the bridge(η^(*))and the average acceleration of the bridge(a^(*)),the difference inη^(*)under different hanging-span ratios is about 59.5%,and the influence on the overall VIV performance of the bridge is increasing,but the a^(*)has limited change.

关 键 词：斜拉悬索协作体系 涡激振动 风洞试验 气动参数 吊跨比 

分 类 号：U441.3[建筑科学—桥梁与隧道工程]