大跨度斜拉桥钢桥塔基于涡振的气动选型及驰振性能风洞试验研究

大型钢桥塔在中国应用较少,其风振特点与常规混凝土桥塔有较大差异.以大跨度斜拉桥“人”字弧线形钢桥塔为工程背景,采用考虑三维绕流特性的气弹模型,针对塔柱可能的断面形式进行了多工况的对比试验,并对风洞试验结果进行分析讨论,进而确定最优断面形式.根据确定的断面形式,对该桥桥塔进行了大缩尺比的气弹模型风洞试验,较全面地考查了该桥桥塔的涡激振动及驰振性能,并对比了阻尼比对桥塔涡激振动振幅及驰振临界风速的影响.试验结果表明:当塔柱断面切角为0.8m×0.7m时桥塔涡振响应最小,相应的扭转驰振临界风速较高.

Vortex-induced-vibration-based aerodynamic optimization and galloping characteristics of steel pylon in long span cable-stayed bridge by wind tunnel test

Large-scale steel pylon is rarely applied in China,and its wind-induced vibration characteristics are quite different from the conventional concrete pylons.In this paper,an arc shaped steel pylon of long span cable-stayed bridge is regarded as a typical example.According to the possible section types of the steel pylon,comparative experiments with many cases were made by the aeroelastic model wind tunnel test.Through analyzing the results of wind tunnel test,the best section type of the steel pylon is determined.Based on the best section type,the performance of vortex-induced vibration and galloping of the steel pylon are extensively investigated,and the effects of damping ratio on the vortex-induced vibration amplitude and critical wind velocity of galloping are comparatively analyzed.The test results indicate that the pylon has a minimum vortex-induced vibration and a relatively high galloping critical wind velocity when the pylon cross section has a corner cut type of 0.8m×0.7m.