分离式双箱梁斜拉桥涡激振动试验研究——以港珠澳江海直达船航道桥为例

Experimental study on vortex-induced vibration of separated box girders in cable- stayed bridges

为了研究分离式双箱梁斜拉桥的涡激振动特性,以港珠澳江海直达船航道桥为研究对象,以风洞试验为研究手段,分析加风障、增设不同开槽率的中央底板、改变腹板角度和增设导流板等气动措施对主梁涡激振动特性的影响,以及在不同风攻角下不同气动断面的涡激振动特点。试验和分析结果表明:风障虽然不能避免涡激振动的发生,但是可以有效地减小涡激振动的振动幅度;底板开槽可以有效地控制涡激振动的发生,并存在1个最佳开槽率;改变幅板角度可以有效地避免二阶涡激振动的发生,但对一阶涡激振动影响效果不明显;相比较而言,导流板设置在断面两侧是对主梁断面进行涡激控制最有效的措施。

In order to study the vortex-induced vibration（VIV） of separate pairs of box girders in cable-stayed bridges,Hong Kong-Zhuhai-Macao River-sea Ship Canal Bridge is taken as an example.Employing a wind tunnel test,the effect of different aerodynamic measures,including adding windbreak,setting grating of different opening ratios,changing incline angle of web,and setting baffle,on the VIV of main girder is respectively studied,and the VIV characteristics of the girder under various aerodynamic measures and different wind attack angles is analyzed.According to the test and analysis,although the windbreak cannot avoid the VIV for the bridge,it can effectively reduce vibration amplitude.The measure of setting grating with different opening ratios is effective,while there is an optimum opening ratio to restrain the VIV.Changing the incline angle of web can restrain the second-order VIV effectively.However,its effect on the first-order VIV is not remarkable.Comparing the aforementioned measures,setting baffles on both sides of the girder is the most effective measure to restrain the VIV.