大跨度铁路桥附属构件对不同宽高比矩形断面涡振性能的影响OA北大核心CSTPCD

Based on the original rectangular box main girder section of four-wire railway bridge with aspect ratio of 6.7∶1 of the completed long-span Bianyuzhou Yangtze River Bridge,the rectangular box girder section of two-wire railway bridge with aspect ratio of 4∶1 and that of six-wire railway bridge with aspect ratio of 9∶1 are designed by adjusting the section aspect ratio.The relationship between the vortex-induced vibration(VIV)characteristics of three commonly used two-,four-and six-wire railway bridge rectangular box girder sections and the corresponding rectangular sections with the same aspect ratios under uniform flow at 0°,±3° and±5° angles of wind attack,as well as the influence of auxiliary components of railway bridge on the VIV performance of rectangular sections with different aspect ratios are investigated through section model wind tunnel tests.The results show that the arrangement of auxiliary components of railway bridge on rectangular sections with the aspect ratios of 4∶1 and 6.7∶1 can increase their VIV amplitudes under negative wind angle of attack,with the increase rate of vertical VIV amplitude up to 277.5％under the angle of wind attack of-5°,but the VIV responses under the positive angle of wind attack can be suppressed to a certain extent.The placement of auxiliary components of six-wire railway bridge on the rectangular section with the aspect ratio of 9∶1 can significantly increase the VIV amplitude of this section under each wind angle of attack,which is above 48.3％of the torsional amplitude increase rate under each angle of attack.The reduction effect of railway auxiliary components on the VIV performance of rectangular sections increases with the increase of section aspect ratio.For the box girders of two-wire and four-wire railway bridges,which with blunt aerodynamic profiles,the VIV characteristics of rectangular sections with similar aspect ratios can be referenced,and the focus should be on examining VIV responses of box girders under negative angle of wind attack.For box girders of six-wire railway bridges with large aspect ratios,due to the large influence of auxiliary components,the significance of referring to the VIV characteristics of rectangular sections with similar aspect ratios is minor,therefore their VIV performances under each wind angle of attack should be investigated in detail.