中央开槽箱形断面斜拉桥的涡激振动试验与分析

为研究斜拉桥采用中央开槽箱形断面时抑制主梁涡激振动的气动措施,以港珠澳大桥江海直达船航道桥为背景,对其主梁节段模型进行涡激振动试验,并结合CFD方法分析对主梁采取3种不同气动措施(增设不同开孔率的底板、改变腹板角度和增设导流板)的有效性。分析结果表明:增设开孔底板可以有效地控制主梁涡激振动的发生,但存在一个最佳底板开孔率;改变腹板角度可以改善主梁涡激振动的性质,但是作为单独的涡激振动控制措施并不很理想;在主梁腹板两侧设置导流板是抑制主梁涡激振动的最有效措施。

Testing and Analysis of Vortex-Excited Vibration of Central Slotted Box Section Cable-Stayed Bridge

To study the aerodynamic measures for suppressing vortex-excited vibration of the main girder of central slotted box section cable-stayed bridge,the river and sea ship channel bridge of the Hong Kong-Zhuhai-Macau Bridge was cited as an example,the vortex-excited vibration testing for the sectional model of the main girder of the bridge was made and in accordance with the CFD method,the effectiveness of three kinds of the different aerodynamic measures to be taken for the main girder,such as utilizing of the bottom plate with different slotting ratios,changing of angles of the webs and utilizing of the guide vanes,was analyzed.The results of the analysis show that the utilizing of the slotted bottom plate can effectively control the occurrence of the vortex-excited vibration on the main girder,but the problem of the best slotting ratio of the bottom plate remains to be determined.The changing of angles of the webs can improve the vibration nature of the main girder,but when the measure is individually used,the effect of the vibration control is not very ideal.Compared with the said two measures,the utilizing of the guide vanes at both sides of the webs of the main girder is the most effective measure that can suppress the vortex-excited vibration.