大跨刚构桥最大悬臂阶段驰振稳定性的数值风洞研究

驰振是一种钝体截面的细长结构在空气中的气动不稳定现象,其振动频率较低。大跨刚构桥最大悬臂施工阶段由于结构较柔,存在发生驰振的可能性,因此必须研究该状态下的驰振稳定性。驰振分析通常借助风洞试验进行,试验周期长,费用高。基于计算流体动力学的数值风洞方法,首先求解不可压雷诺时均N—S方程,获得桥梁主梁截面的气动力特性,然后通过求解结构驰振运动方程,以评价大跨刚构桥最大悬臂施工阶段的驰振稳定性。用于贵阳小关连续刚构桥最大悬臂施工阶段横风向驰振稳定性分析,研究表明该桥在最不利施工状态不会发生驰振。

Galloping analysis of long-span rigid frame bridge during the maximum cantilever stage by using numerical simulation methods

Galloping is an aeroelastic instability phenomenon of elongated bluff bodies with relatively low oscillatory frequency in air stream.During the maximum cantilever construction stage of long-span rigid frame bridge,the structure is sensitive to wind because of its flexibility,it is necessary to study the galloping stability,which is always carried out in wind tunnel tests with longer testing periods and higher costs.In this paper,a method based on the computational fluid dynamics and Reynolds Averaged Navier-Stokes equations was presented to obtain aerodynamic force coefficients of main girder in cross wind.Then structural galloping equation of motion was employed to evaluate galloping instability of the long-span bridge in maximum cantilever stage.Finally,this method was used to deal with the galloping stability analysis of the long-span Xiao Guan rigid frame bridge located in Guiyang in construction stage,the results confirmed that this bridge will not suffer from galloping stability during the maximum cantilever construction stage.