Abstract Galloping instability can potentially threaten the modern launching of steel-concrete composite bridge girders, due to light weight and bluff shape of the steel box, which is normally launched first. A bridge deck with typical open cross section was selected and investigated in smooth flow through wind tunnel techniques. Aeroelastic tests showed that the classical instability arising from the interaction between vortex-induced vibration and galloping may occur for a mean flow incidence of 4°, fixing the actual galloping onset at the Karman-vortex-resonance wind speed up to a high value of the mass-damping parameter. In contrast, a different and more complicated behavior was observed for a mean flow incidence of 0°, where the actual galloping instability occurs at a wind speed clearly higher than the Karman-vortex-resonance wind speed even for a very low value of the mass-damping parameter. Static tests further indicated that the most evident difference between the two cases is the magnitude of the vortex shedding force, which is much lower for a null angle of attack. A rectangular cylinder with the same side ratio was also tested for the sake of comparison. Finally, Tamura’s wake-oscillator model was implemented for the bridge deck at a mean flow incidence of 4°, following a recently proposed parameter identification method. The mathematical model was found to be able to give some promising predictions even for a complex bridge deck profile.

中文翻译：

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开敞断面桥面非定常飞驰试验研究与数学建模

摘要 由于通常先下水的钢箱体重量轻、呈钝角，飞驰失稳可能威胁到现代钢-混凝土组合桥梁的下水。选择了具有典型开放横截面的桥面板，并通过风洞技术进行了平滑流动的研究。气动弹性测试表明，涡激振动和疾驰之间相互作用引起的经典不稳定性可能发生在 4°的平均气流入射角，将卡门涡旋共振风速下的实际疾驰开始固定到高值质量阻尼参数。相比之下，对于 0° 的平均流动入射角，观察到不同且更复杂的行为，其中，即使质量阻尼参数的值非常低，实际的疾驰不稳定性也发生在明显高于卡门涡旋共振风速的风速下。静态测试进一步表明，这两种情况之间最明显的区别是涡旋脱落力的大小，对于零攻角来说，它要低得多。为了比较，还测试了具有相同边长比的矩形圆柱体。最后，根据最近提出的参数识别方法，在平均流入射角为 4° 的情况下，对桥面板实施了 Tamura 的尾流振荡器模型。发现数学模型即使对于复杂的桥面轮廓也能给出一些有希望的预测。静态测试进一步表明，这两种情况之间最明显的区别是涡旋脱落力的大小，对于零攻角来说，它要低得多。为了比较，还测试了具有相同边长比的矩形圆柱体。最后，根据最近提出的参数识别方法，在平均流动入射角为 4° 的情况下，对桥面板实施了 Tamura 的尾流振荡器模型。发现数学模型即使对于复杂的桥面轮廓也能给出一些有希望的预测。静态测试进一步表明，这两种情况之间最明显的区别是涡旋脱落力的大小，对于零攻角来说，它要低得多。为了比较，还测试了具有相同边长比的矩形圆柱体。最后，根据最近提出的参数识别方法，在平均流入射角为 4° 的情况下，对桥面板实施了 Tamura 的尾流振荡器模型。发现数学模型即使对于复杂的桥面轮廓也能给出一些有希望的预测。根据最近提出的参数识别方法，Tamura 的尾流振荡器模型在平均流入射角为 4° 时用于桥面板。发现数学模型即使对于复杂的桥面轮廓也能给出一些有希望的预测。根据最近提出的参数识别方法，Tamura 的尾流振荡器模型在平均流入射角为 4° 时用于桥面板。发现数学模型即使对于复杂的桥面轮廓也能给出一些有希望的预测。