大攻角及桥面粗糙度对扁平钢箱梁涡振性能的影响

摘要

To study effects of deck roughness and large attack angle on vortex-induced vibration,wind tunnel test has been performed.First,deck roughness was obtained in numeric simulation and according to which,the best match sandpapers were selected for the experiment.Tests of bridge section model were performed with different kinds of attack angles and bridge deck roughness.The results show that the vertical and torsional vortex-induced vibration of flat steel box girder with a large aspect ratio increase at the large attack angle.When the bridge locates in the mountains,it is necessary to do bridge section model test at large attack angle.Deck roughness can reduce the vertical and torsional vortex-induced vibration. Deck roughness has influence on vortex-induced vibration which increases correspondingly with the decrease of the attack angle.Response of torsional vortex-induced vibration is more sensitive to deck roughness,and its range is greater than that of vertical vortex-induced vibration.The accuracy of deck roughness affects the reliability of wind tunnel test.%为探究大攻角及桥面粗糙度对扁平钢箱梁涡振性能的影响，对寸滩长江大桥主梁进行了风洞试验。应用 Matlab 软件模拟桥面粗糙度变化范围，根据模拟结果选取对应的砂纸在试验中模拟桥面粗糙度，分析了攻角及桥面粗糙度对扁平钢箱梁涡振区间及幅值的影响。试验研究表明：在大攻角下扁平钢箱梁的涡振振幅和范围明显增大，对桥址位于山区等容易发生大风攻角的地区的桥梁应进行大攻角试验。扁平钢箱梁的涡振响应随着桥面粗糙度增大而减小。正攻角范围内，桥面粗糙度对涡振响应的影响随着攻角减小而增大。桥面粗糙度发生变化时，扭转涡振响应更加敏感，变化幅度大于竖向涡振响应变化幅度。