Abstract: In the laboratory, the T-beam simply supported plexiglass model bridge was loaded in multiple stages. The 3D point cloud data of the bridge deck was collected by using the 3D laser scanning system. The point cloud deformation data of bridge deck under different working conditions were analyzed, and the variation law of Gauss curvature cloud of bridge deck caused by different locations and numbers of damage of main girder was numerically analyzed by finite element method. For the three representative working conditions of the model bridge-non-damaged no-load, non-damaged full-load and damaged full-load, the bridge surface Gaussian curvature cloud map obtained by finite element data and point cloud data was compared and analyzed.The 3D laser plane point cloud data was attempted to link with the damage of the bridge structure,and the damage identification method of the bridge structure based on the variation of the bridge surface Gaussian curvature was explored.The results show that the Gauss curvature of the bridge is more sensitive to the damage than the change of the deflection.The number and location of structural damage can be identified by the variation of the Gauss curvature of bridge deck, which provides a reference for structural damage identification on real bridges in the future.

Key words: bridge engineering, bridge structure, 3D laser scanning, damage identification, Gaussian curvature

摘要： 在实验室内对T型简支有机玻璃模型桥进行了多级加载，使用三维激光扫描系统采集了桥面三维点云数据，分析了不同工况下的桥面点云变形数据云图，有限元数值分析了主梁不同位置和不同数量损伤所引起的桥面高斯曲率云图变化规律。针对模型桥中3种代表性工况：无损伤空载、无损伤满载和有损伤满载，将有限元数据和点云数据分别所得到的桥面高斯曲率云图进行了对比分析，尝试将桥面三维激光平面点云数据与桥梁结构损伤情况联系起来，探索了基于桥面高斯曲率变化进行的桥梁结构损伤识别方法。结果表明：桥面高斯曲率相对于挠度变化来说对损伤更敏感，通过桥面高斯曲率的变化规律可识别结构损伤的数量和位置等特征，为将来在实桥上利用桥面曲率变化进行结构损伤识别提供了参考。

关键词: 桥梁工程, 桥梁结构, 三维激光扫描, 损伤识别, 高斯曲率