The safe operation of bridges in service is a worldwide problem; thus, it is significant to ensure the health and stability of bridge structures. For large bridges, considerable progresses have been made in theoretical research and monitoring system. Since the inherent characteristics of medium–small span bridges, such as low cost and minute deformation, the methods applied to large bridges are not suitable for them. Therefore, this paper presents a new method that offers low cost, real‐time dynamic monitoring, and simple equipment for monitoring medium–small span bridges. In addition, a new device called tilt angle elimination device is designed to eliminate the influence of inclination. Based on laser projection technology and image processing technology, we employ laser and charge‐coupled device camera to monitor. Then we validate the effectiveness of new method by conducting a series of experiments. Results show that the new method and device have good utility. To sum up, this displacement monitoring method can provide reference data for the performance evaluation of bridges, which is valuable in the diagnosis of bridges.

中文翻译：

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基于激光技术的中小跨度桥梁中位移监测

在役桥梁的安全运行是一个世界性的问题。因此，重要的是确保桥梁结构的健康和稳定。对于大型桥梁，理论研究和监测系统已经取得了相当大的进步。由于中小跨度桥梁的固有特性（例如低成本和微小变形），适用于大型桥梁的方法不适合它们。因此，本文提出了一种新的方法，该方法可提供低成本，实时动态监视和用于监视中小跨度桥梁的简单设备。另外，设计一种称为倾斜角消除装置的新装置以消除倾斜的影响。基于激光投影技术和图像处理技术，我们使用激光和电荷耦合设备的摄像头进行监控。然后，我们通过进行一系列实验来验证新方法的有效性。结果表明，该新方法和装置具有良好的实用性。综上所述，这种位移监测方法可以为桥梁的性能评估提供参考数据，对桥梁的诊断具有重要的参考价值。