摘要
为研究双幅Π型叠合梁的涡振特性以及相应的气动减振措施,以贵州省乌当至长顺高速公路金旗特大桥的双幅Π型叠合梁为背景,采用缩尺比为1∶40的节段模型进行风洞试验,先在0°、±3°、±5°风攻角下,研究单幅梁和双幅梁的涡振特性;再研究涡振振幅最大风攻角下不同间距比(双幅梁净间距与单幅梁宽度之比)和阻尼比对双幅梁涡激振动的影响;最后研究安装不同尺寸的倒L型导流板对主梁涡振振幅的减振效果。结果表明:在+5°风攻角下,双幅梁的涡振响应最为明显,与单幅梁相比,双幅梁的涡振振幅变大。随着间距比的增大,双幅梁的竖弯最大振幅先增大后减小;随着阻尼比的增大,主梁的竖弯最大振幅逐渐减小。安装不同尺寸的倒L型导流板均能降低双幅梁的涡振振幅,其中L4-3(对应实桥水平和竖向尺寸分别为160 cm和120 cm)倒L型导流板降低效果最显著。
This study investigates the vortex-induced vibration(VIV)characteristics of bridge with superstructure consisting of twinΠ-shaped composite girders and vibration mitigation measures.Based on the Jinqi Bridge of Wudang-Changshun Expressway,a 1∶40 sectional model of twinΠ-shaped composite girders were prepared for wind tunnel tests.First,the VIV characteristics of a singleΠ-shaped girder and the twinΠ-shaped girders were examined at the wind attack angles of 0°,±3°and±5°,respectively.Second,the influences of the D/B(representing the ratio of net spacing of twoΠ-shaped girders and width of oneΠ-shaped girder)and damping coefficient computed at the wind attack angle inducing the maximum VIV response on the VIV characteristics of twinΠ-shaped composite girders were analyzed.Third,the vibration mitigation effects of inverted L-shaped wind baffles of different dimensions were studied.It is shown that both the twinΠ-shaped girders exhibited significant VIVs at the wind attack angle of 5°,the vibration amplitudes of the former was greater.In the twinΠ-shaped girders,the maximum vertical bending varied from increase to decrease,as the damping coefficient increased,the VIV amplitudes gradually decreased.The inverted L-shaped wind baffles of all the selected dimensions can suppress the VIVs of the twinΠ-shaped girders,and the inverted L-shaped wind baffles labeled L4-3 measuring 160 cm(along horizontal direction in the real bridge)by 120 cm(along vertical direction in the real bridge)perform best.
作者
安路明
AN Luming(China Railway Construction Bridge Engineering Bureau Group Co.,Ltd.,Tianjin 300300,China;School of Civil Engineering,Shijiazhuang Tiedao University,Shijiazhuang 050043,China)
出处
《世界桥梁》
北大核心
2025年第4期87-94,共8页
World Bridges
基金
国家自然科学基金项目(52408551)。
关键词
斜拉桥
双幅Π型叠合梁
风攻角
间距比
阻尼比
涡振特性
减振措施
风洞试验
cable-stayed bridge
twinΠ-shaped composite girders
wind attack angle
spacing ratio
damping ratio
vortex-induced vibration characteristics
vibration mitigation measure
wind tunnel test
