钢桥塔涡激共振振幅允许值研究-桥梁与隧道工程专业论文.docxVIP

 I 摘 要 钢桥塔具有质量轻、阻尼小、对风荷载敏感等特点，易发生涡激共振。桥塔涡激共 振虽然是限幅振动，但其在较低风速下就会发生，且振幅之大足以影响到结构的强度和 疲劳，同时也会影响到桥塔施工机械的安全性、施工人员的安全性和舒适性，所以必须 采取抑振措施限制桥塔涡振振幅在允许范围内，因此研究钢桥塔涡振振幅允许值就具有 非常重要的意义。 本文以江海直达桥方案 I、江海直达桥方案 II 和南京长江三桥桥塔为算例，研究了 钢桥塔涡激共振振幅允许值以及振幅允许值与钢塔柱高的关系，并总结出以塔高为参数 的允许振幅估算公式。研究中主要以钢主梁涡激共振产生的主梁控制截面最大允许应力 与主梁钢材容许应力的比值为参照，认为钢桥塔涡激共振产生的塔控制截面最大允许应 力与塔钢材容许应力的比值与主梁的比值相等。这样由桥塔钢材容许应力就可以得到桥 塔涡振产生的塔控制截面的允许应力。再以这个允许应力为控制条件得到桥塔的允许振 幅。研究成桥状态钢塔顺桥向弯曲涡振允许振幅时，同时以主梁竖向振动允许振幅为控 制条件，即认为由桥塔涡激振动引起的主梁竖向振幅不应超过允许值。 此外，本文还对桥塔涡振振幅达最大允许值时，塔顶施工作业舒适度进行了评价。 最后介绍了算例桥塔的气弹模型风洞试验，并将试验结果与研究得到的允许值进行了比 较。 关键词：钢桥塔 涡激共振 允许振幅 控制截面 允许应力 风洞试验 II Abstract Steel bridge towers have the characteristics of light weight, small damping, sensitivity to wind and so on, are prone to vortex-induced resonance. Vortex-induced resonance of pylon is a limiting vibration, but it occurs at low wind speeds, and the amplitude is large enough to affect the structural strength and fatigue, it can also affect the security of the construction machinery, construction workers and the comfort of the construction workers. It is necessary to take measures to limit the damping amplitude of pylon vortex-induced resonance within the allowable range. Therefore studying the allowed values of vortex-induced resonance amplitude of steel bridge towers is very significant. This paper takes the towers of Jianghai Zhida Bridge plan I, Jianghai Zhida Bridge plan II and 3th Nanjing Yangtze River Bridge as examples, studies the allowed values of vortex-induced resonance amplitude of steel bridge towers and the relationship between allowed values and tower height, and summed up an estimate formula of the allowable amplitude about tower height. Taking the ratio of the maximum allowable stress produced by main beam vortex-induced resonance and permissible stress of steel as a reference, assuming the ratio of maximum allowable stress of the tower control section produced by tower vortex-induced resonance and permissible stress of tower stell is equal to main beam. So