WANG Yangxue1,LIU Qingkuan1,2,3,JING Hongmiao1,2,3,LI Zhen1,SUN Yifei1
JOURNAL OF VIBRATION AND SHOCK. 2023, 42(6): 232-239.
Vortex-induced vibration (VIV) is a kind of wind-induced self-limiting vibration with both forced and self-excited characteristics, which is easy to occur in long-span bridges at low wind speeds. The railings, subsidiary facilities of the bridge deck, have a significant influence on the VIV performance, as a results of its variation in aerodynamic shape of the main girder. To reveal the influence and mechanism of inclined railings on VIV performance of streamlined box girder. The pressure distribution and displacement respond of sectional model were carried out by wind tunnel tests. The VIV response, mean and fluctuating wind pressure coefficient distribution were comprehensively studied. Meanwhile, correlation and contribution coefficients, as well as phase difference between local aerodynamic force and vortex-excited force also were comprehensively studied. The results indicate that when the sidewalk railing inclined inward, the greater the inclined angle, the more obvious the vibration suppression effect. When the sidewalk railing is inclined outward, the vibration suppression effect of the main beam with 10° inclined outward is better than that of the main beam with 20° inclined outward; compared with the conventional vertical railings, the main reasons why the railings inclined 20° inward and 10° outward have obvious vibration suppression effect are as follows: the fluctuating wind pressure coefficients on the upper and lower surfaces of main girders are considerably lower, decreasing by 61.54 % in the most obvious regions; the correlation coefficient between local aerodynamic force and vortex-excited force is reduced by about 33.33% on average, in most areas of the upper surface of the main beam.; the vortex-induced contribution coefficients are reduced to varying degrees in the upstream front, downstream tail and most areas of the lower surface; the continuity of the phase differences between the measurement points are interrupted, and the phase differences become scattered.