带吊机钢桥塔施工状态抖振响应及风振舒适性研究

Study of Buffeting Response and Wind-Induced Vibration Comfort of a Steel Pylon with a Tower Crane in Construction Stage

为评估施工过程中带吊机状态时桥塔的风振舒适性,对某桥一高164.4 m的独柱式钢桥塔与吊机结构开展了气动弹性模型风洞试验,研究桥塔封顶(T1状态)以及最后一道扶墙安装前(T2状态)2种施工状态下的桥塔和吊机的抖振位移响应;采用加速度均方根作为结构风振舒适性评价指标,通过比较多种舒适性标准得出高、中、低3种评价等级,对带吊机桥塔结构风振舒适性进行评价,并结合工程规定进行验证。结果表明:风偏角对带吊机钢桥塔结构抖振响应有显著影响,其中15°风偏角下抖振响应最大;风速与带吊机钢桥塔结构顶部加速度均方根间存在较显著的线性正相关特性,可以作为风振舒适性的简易评价指标;2种施工状态下桥塔塔顶风振舒适性基本一致,T2状态下吊机顶部风振舒适性低于T1状态;3种评价标准中基于非常烦扰的中评价等级与工程规定较相符。

Based on the aerodynamic model of a mono-column steel pylon rising 164.4 m under construction,the wind tunnel test was conducted to evaluate the comfort of the pylon with a tower crane under the action of wind-induced vibration.The buffeting displacement responses of the pylon and the tower crane were studied during the capping of the pylon(T1)and the installation of the last buttress(T2).The root mean square of acceleration was applied as the index to evaluate the human response to the wind-induced vibrations of pylon.Multiple human comfort standards were compared to categorize three levels(high,medium and low level)of evaluation.The evaluation levels were verified in accordance with the related requirements.The results show that the wind yaw angle can exert significant effect on the buffeting response of the pylon structure with tower crane,and the buffeting response is the most violent at the wind yaw angle of 15°.The root mean square of acceleration of the top of the steel pylon with a tower crane is in distinct linear relation with the wind speed,which can be used as one of the simple evaluation index of the comfort of the pylon under the action of wind-induced vibration.The comfort level of the pylon is similar in the two construction stages,while the comfort of the top of the tower crane under the action of the wind-induced vibration is lower in condition T2,compared to that in condition T1.The medium level of evaluation that is based on the very-disturbing degree generally agrees with the specified level.