主跨100m悬挂式单轨斜拉桥抗风性能研究

Research on wind resistance performance of suspended monorail of 100m main span cable-stayed bridge

本研究基于武汉光谷悬挂式单轨项目,对工程中一座主跨100m悬挂式单轨斜拉桥的抗风性能进行研究。鉴于其新颖的制式、独特的主梁断面形式、较大的跨度以及钢结构较小的阻尼比,其抗风性能的研究具有十分重要的工程意义。本研究首先通过Ansys进行全桥动力特性分析,获取主梁的各阶模态频率与振型。其次采用CFD研究主梁标准断面气动力,获取主梁断面的静三分力系数;并对升力系数进行傅里叶变换分析,得到可能发生涡振的风速为21.24m/s与10.25m/s。最后对主梁断面进行“流固耦合”分析,得出结论:主梁风速为11m/s时,发生竖向涡振;当风速为23m/s时,发生扭转涡振,且扭转位移超限;因此,建议设置一定的气动措施或者设置阻尼器等方法降低涡振幅值[1],以保证行车安全性。

Based on the suspended monorail project of Wuhan Optical Valley,this paper studies the wind resistance performance of the suspended monorail of a cable-stayed bridge with a main span of 100m.In view of its novel system,unique section form of main beam,large span and small damping ratio of steel structure,it is of great engineering significance to study its wind energy resistance performance.In this research,the dynamic characteristics of the whole bridge are analyzed by ANSYS to obtain the modal frequencies and formation of the main beam.Secondly,CFD is used to study the aerodynamic force of the standard section of the main beam and obtain the static three-component coefficient of the main beam section.The lift coefficient is analyzed by Fourier transform,and the wind speed that may cause vortex vibration is 21.24m/s and 10.25m/s.Finally,the‘fluid-structure coupling’analysis of the main beam section is carried out,and the conclusion is drawn:when the wind speed of the main beam is 11m/s,the vertical vortex vibration occurs;When the wind speed is 23m/s,torsional vortex vibration occurs and the torsional displacement exceeds the limit;Therefore,it is recommended to set certain aerodynamic measures or set dampers to reduce the amplitude of vortex vibration to ensure driving safety.