To study the influence of aerodynamic interferece on the three-component coefficient and vortex vibration property of the twin parallel bluff box girders,and provide reference for the static load values and vortex resistant design for the the box girders of such type,the wind tunnel test of using segmental model made based on the mid-span cross section of a certain twin parallel bluff box girders to test pressure and vibration was conducted to test the three-component coeffi-cient and the behaviors of vortex-induced vibration of the twin parallel bluff box girders with large intervals.The results were compared with the three-component coefficient and the behaviors of vortex-induced vibration of the single bluff girder.The comparison shows that the influence of aer-odynamic interference on the three-component coefficient of twin parallel bluff box girders reflects on the dow nstream bluff box girder,and mainly the mitigation effect,w hen 1≤ D/B≤6(D refers to the net distance between the two box girders and B represents the width of the box girder)and the wind attacking angle is within the range of -10°~10°.Nevertheless,when the value of D/B is 3 and the attacking angle is within the range of -4°~4°,the aerodynamic interference has a cer-tain amplification effect on the vortex-induced vibration of the dow nstream bluff box girder,w hich is specifically reflected by the enlargement of the vibration amplitude and the elongation of the in-tervals of wind speed locking region,and compared with the positive attacking angle,the amplifi-cation effect in the case of negative attacking angle is more distinct.%为研究气动干扰对大间距并列双钝体箱梁的三分力系数和涡振特性的影响,给这类箱梁静风荷载取值和涡振抗风设计提供参考,根据某并列双钝体箱梁桥跨中断面,制作节段缩尺模型,通过测压和测振风洞试验,测试大间距并列双钝体箱梁的三分力系数和涡振特性,并与单幅钝体箱梁的三分力系数和涡振特性进行对比.结果表明:当1≤ D/B≤6(D为双箱梁的净间距,B为单箱梁宽),风攻角为-10°~10°时,气动干扰对并列双钝体箱梁三分力系数的影响表现在下游钝体箱梁上,且主要体现为减小效应;当 D/B=3,风攻角为-4°~4°时,气动干扰对下游钝体箱梁的涡振有一定的放大效应,表现为振幅的增大和风速锁定区间长度的变长,与正攻角相比,负攻角时的放大效应更显著.
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