Abstract: As a rapidly developing surveying and mapping tool in recent years, 3D laser scanning technology has become an important part of the monitoring technology in bridge health monitoring. In this paper, taking a cross-river bridge in Wuhan as an example, a Trimble SX10 3D laser scanner is used to scan the bridge for long-term monitoring, and the point clouds of the bridge steel structure and piers are sectioned. Then the scanned point clouds of each phase are processed with the help of Trimble Business Center and Trimble RealWorks software to extract the point coordinates of the bridge arch sections and perform the best vertical cylinder fitting of the bridge pier slicing point clouds. It obtains the coordinates of the fitted plane center points, compares and analyzes the deviations and 3D offsets of the plane coordinates of the feature points of each phase. The research results of this paper verify the feasibility of 3D laser scanner in bridge deformation monitoring, enrich the bridge monitoring data presentation, and can provide the basis and reference for related research.

Key words: bridge deformation, 3D laser scanning, point cloud slicing, best vertical cylinder fitting, feature points