5000m特大跨度悬索桥空气动力稳定性风洞试验研究

Wind tunnel test on the aerodynamic stability of super-long span suspension bridge with a main span of 5000m

伴随跨海大桥建造时代的来临,特大跨度悬索桥的空气动力性能研究日益紧迫,设计了中跨跨度为5000m的宽开槽和窄开槽钢箱梁悬索桥方案,实现了5000m特大跨度钢箱梁悬索桥的节段模型风洞试验,研究了宽开槽和窄开槽两种方案的颤振性能,识别了其颤振导数、颤振风速、颤振频率、三分力系数等重要参数;其次在风洞试验中研究了多种稳定板组合方案对窄开槽钢箱梁的颤振控制作用,发现中央稳定板和上稳定板的组合能将颤振临界风速提高50%;最后提出了适用于特大跨度悬索桥的二维颤振Straight-forward Method分析方法,对风洞试验进行了数值模拟,验证了该方法和节段模型风洞试验对于5000m悬索桥分析结果的一致性。最终研究认为:中央开槽达到足够宽度的方案与窄开槽附加稳定板的方案都能为跨度5000m的悬索桥提供足够高的颤振失稳临界风速,并能满足世界上绝大多数台风区的要求。

The bridge aerodynamic stability research is an urgent topic since bridge construction has entered into a new era of crossing wider sea straits. In this paper, a trial design of a 5000m suspension bridge with narrow and wide slotted steel boxes is conducted; then sectional model wind tunnel test is carried out as the first case of 5000m suspension bridge, identifying the flutter derivatives, flutter frequencies and three dynamic coefficients. Also the influence of various combination of additional stabilizers on vibration control of the narrow slotted girder are checked, finding out that the horizontal stabilizer above the narrow slotted girder can increase the critical flutter speed by 50 %. Finally the Straight-forward Method for analysis of two dimensional flutter of super long span suspension bridge is proposed to check the wind tunnel results and research shows the compatibility of wind tunnel test and Straight-forward Method. Total conclusions can be drawn that both the wide slotted girder and narrow slotted girder with additional stabilizers can be feasible solutions for 5000m suspension bridge located in most of the typhoon prone areas around the world form the point of aerodynamic.