超高桥塔的气弹模型风洞试验及其等效静力风荷载

Aeroelastic model wind tunnel test and equivalent static wind load for superhigh bridge tower

为研究超高桥塔的气弹模型风洞试验方法及其等效静力风荷载,根据某实际工程中的超高桥塔建立了有限元模型,进行了动力特性计算,进而设计了相应的气弹模型,并开展了风洞试验。在此基础上,开展了超高桥塔风致振动的非线性时程计算,并基于阵风荷载因子法,对比了以位移、内力和应力为单一目标的超高桥塔的等效静力风荷载。结果表明:斜风作用下的桥塔风致振动比较显著,其影响随着风速的增大而愈加明显;当风向角为75°~90°时,超高桥塔将在风速为35~50 m·s^(-1)的区间发生顺桥向的侧弯涡振,但幅值较小;基于应力的阵风荷载因子比基于位移或内力的阵风荷载因子更加稳定,这使得基于应力的等效静力风荷载要优于基于位移或内力的等效静力风荷载,比较适合于超高桥塔。

In order to study the wind tunnel test method and equivalent static wind load of the aeroelastic model of superhigh bridge towers,a finite element model was established based on a superhigh bridge tower in a practical project,and dynamic characteristics were calculated.Subsequently,a corresponding aeroelastic model was designed and wind tunnel tests were conducted.On the basis,nonlinear time-history calculations of wind induced vibration of superhigh bridge towers were carried out.Based on the gust load factor method,the equivalent static wind load of superhigh bridge towers with displacement,internal force,and stress as a single objective was compared.The results show that the wind-induced vibration of the bridge tower under the action of oblique wind is relatively significant,and its impact becomes more pronounced as the wind speed increases.When the wind direction angle is from 75°to 90°,the superhigh bridge tower will experience lateral bending vortex vibration along the bridge direction in the range of wind speed is from 35 m·s^(-1)to 50 m·s^(-1),but the amplitude is small.The gust load factor based on stress is more stable than the gust load factor based on displacement or internal force,which makes the equivalent static wind load based on stress superior to the equivalent static wind load based on displacement or internal force,making it more suitable for super high bridge towers.