Abstract: Advances in 3D laser scanning and point cloud processing technologies have promoted the application of point cloud-based structural dimension measurement in bridge engineering. To efficiently obtain the length of stay cables for supporting inspection and maintenance, a measurement method based on point cloud model was developed. The proposed method acquired a 3D point cloud model of the stay cables through high-precision 3D laser scanning, enabling automatic identification and precise calculation of the cable length. The point cloud model was discretized into multiple segments, and the central coordinates of each segment were calculated and used as the cable alignment coordinates. Combined with on-site tape measurements and design data, the total length of the stay cable was calculated out. Finally, tests were conducted on the Yiling Yangtze River Bridge. The research results indicate that the cross-sectional errors of the stay cables are all less than 1%. The proposed measurement method can quickly and accurately obtain the cable length, providing support for bridge health monitoring.

Key words: bridge engineering; stay cable; cable length measurement; laser scanning; point cloud model

摘要： 三维激光扫描与点云处理技术的进步，推动了基于点云的结构尺寸测量在桥梁工程的应用。为了高效获取斜拉索索长以支持检测维护，研发了一种基于点云模型的斜拉索索长的测量方法。该方法通过高精度三维激光扫描获取斜拉索的三维点云模型，并自动识别并精确计算索长；将点云模型离散化为多个切段，计算各切段中心坐标，并以此作为索线形坐标，结合现场尺量及设计数据，即可计算斜拉索总长；最后在夷陵长江大桥进行了试验。研究结果表明：斜拉索截面误差均小于1%，该测量方法可快速准确获取索长，为桥梁健康监测提供支持。

关键词: 桥梁工程；斜拉索；索长测量；激光扫描；点云模型