风雨联合作用下大跨桥梁颤振稳定性试验研究

Experimental study on the flutter stability of long-span bridges subjected to wind and rain

针对风雨联合作用下的大跨桥梁颤振稳定性,以一开槽双箱梁桥梁为研究对象,通过在大气边界层风洞中搭建的风雨联合作用试验系统,完成基于自由振动法的节段模型颤振试验。通过分析不同雨强下该桥梁主梁的颤振导数以及颤振临界风速,进而获取降雨对大跨桥梁颤振稳定性的影响规律。试验结果显示:颤振导数随雨强变化而变化,其中体现扭转气动阻尼特性的颤振导数变化较为显著,随雨强增大,颤振临界风速先增大后减小。试验结果表明:降雨对大跨桥梁的颤振导数以及颤振临界风速均有一定影响。

The flutter test, based on free vibration test of a s separated twin-box bridge section model, was carried out by considering the flutter stability of a long-span bridge under the simultaneous actions of wind and rain, utilizing the system of simultaneous actions of wind and rain built in an atmospheric boundary layer wind tunnel. Through analyzing the flutter derivatives and critical flutter wind speeds of the bridge model under different rainfall intensities, the flutter stability of the bridge influenced by rainfall was determined. Experimental results display large variations in the flutter derivatives for different rainfall intensities. The flutter derivative, which reflects the torsional aerodynamic damping action on torsional vibration, changes most significantly. Critical flutter wind speed increases at first then decreases with the enhancement of rainfall intensity. The results show that rainfall may affect the flutter derivatives and critical flutter wind speeds of long-span bridges.