多孔扰流板对半封闭窄箱梁涡振的减振效果

大跨度桥梁涡激共振是影响桥梁运营阶段行车舒适性和桥梁构件疲劳寿命的重要因素。以某半封闭钢箱梁斜拉桥为工程背景，通过节段模型风洞试验研究了在宽高比约为8．1的半封闭窄箱梁底板外缘安装多孔扰流板气动措施的涡振减振效果。结果表明：对于这类半封闭窄箱梁，在上游侧安装多孔板的减振效果略好于上下游两侧同时安装多孔板的减振效果，只在下游侧安装多孔板的减振效果要明显不如前二者；此外，多孔板悬挑宽度对其涡振减振效果也有较大影响，一般来说多孔板悬挑宽度越大，减振效果越好，尤其是对于只在下游侧安装多孔板的情况，多孔板悬出宽度对减振效果的影响更明显。

Mitigation effect of multi-orifice flow-disturbing plate on vortex-induced resonance of narrow semi-closed box deck

Vortex-induced resonance of long-span bridges is an important factor reducing the comfort of vehicle driving and the life-span of bridge components due to fatigue. Taking a cable- stayed bridge with a narrow semi-closed steel box deck with a width-depth ratio of about 8.1 as an engineering background, the mitigation effect of multi-orifice flow-disturbing plates （MOFDP）, jutting horizontally out of the outer edges of the bottom plates of the semi-close box deck, on the vortex-induced resonance of the cable-stayed bridge was investigated through a se- ries of wind tunnel tests of sectional model. The test results show that for such kind of narrow semi-closed steel box deck, the mitigation effect of MOFDP mounted only at the windward edge of the windward box bottom plate is somewhat better than that of the MOFDPs mounted simulta- neously at both the windward edge of the windward box bottom plate and the leeward edge of the leeward box bottom plate. The mitigation effect of MOFDP mounted only at the leeward edge of the leeward box bottom plate is significantly worse than the former two. Moreover, the protru- ding length of the MOFDP can notably affect the mitigation effect, especially for that of the MOFDP at the leeward edge of the leeward box bottom plate. Generally, the longer the protru- ding length of MOFDP is, the better the mitigation effect.