The mechanical properties of bridge bearings gradually deteriorate over time, resulting from daily traffic loading and harsh environmental conditions. However, efficient detection of in-service bridge bearings is still challenging, especially in quantifying support stiffness. This study presents a bridge bearing condition assessment framework of a simply elastic supported beam based on impact vibration testing and structural flexibility identification. Firstly, the dynamic response equation of a simply supported beam with elastic boundary constraints is established. The modal orthogonality of Euler-Bernoulli beams and the corresponding overall matrix of undetermined coefficients are derived using the separate variable method. Subsequently, the flexibility matrix of the simply elastic supported beam is derived and verified in the cases of forward and inverse analysis, respectively. Furthermore, the vertical and rotational stiffness of the bearings are established based on the structural flexibility matrix. Finally, experimental verification is performed to identify the flexibility and the vertical support stiffness of the simply elastic supported beam based on impact vibration tests. The results indicate that the proposed the bearing condition assessment framework can straightforwardly quantify support stiffness.

中文翻译：

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基于冲击振动试验的简弹支撑梁承载状态评估

由于日常交通荷载和恶劣的环境条件，桥梁支座的机械性能随着时间的推移逐渐恶化。然而，有效检测在用桥梁支座仍然具有挑战性，特别是在量化支撑刚度方面。本研究提出了一种基于冲击振动试验和结构柔性识别的简弹性支撑梁桥梁承载状态评估框架。首先，建立了具有弹性边界约束的简支梁的动力响应方程。使用分离变量法导出了欧拉-伯努利梁的模态正交性和相应的待定系数总体矩阵。随后，推导了简弹性支撑梁的柔度矩阵，并分别在正、逆分析情况下进行验证。此外，轴承的垂直和旋转刚度是根据结构柔性矩阵建立的。最后，通过冲击振动试验验证简弹支撑梁的柔度和竖向支撑刚度。结果表明，所提出的轴承状况评估框架可以直接量化支撑刚度。