基于抖振分析的分幅式斜拉桥施工期抗风措施研究

Wind-resistance measures for separate roadway cable-stayed bridge during construction based on buffeting analysis

以分幅组合梁斜拉桥泉州湾跨海大桥为工程背景,分析了施工期最大单悬臂状态和最大双悬臂状态下结构的动力特性,通过模拟桥址区主梁和桥塔的脉动风场,风荷载的时域化,实现了大跨分幅组合梁斜拉桥施工期最不利工况下的抖振时域分析,并针对性地提出有效制振抗风措施。研究表明:泉州湾跨海大桥在施工期设计风速下不会发生分幅主梁相互碰撞;相比设置抗风索的制振措施,将主梁与墩旁托架临时固结的方式更为有效。

Taking a long-span separate roadway composite beam cable-stayed bridge named Quauzhou Bay Bridge over sea as an engineering example, we discussed the dynamic characteristics of structure during construction with max single and double cantilever state. Time-domain buffeting analysis was conducted for long-span separate roadway composite beam cable-stayed bridge in the worst work condition during construction, which is based on simulation of fluctuating wind field in bridge location and time domain transformation for wind load, and effective resistance measures on wind were relatively presented. The study shows that separate composite beam will not impact with each other under the design wind speed during construction stage for Quanzhou Bay Bridge over sea, the way of temporary consolidation between beam and bracket to resist vibration is better than the measure of setting wind cable.