Abstract:To evaluate the status of bridge operation precisely, according to the bridge 3D point cloud model obtained at different times, a change detection method of geometrical profile of bridges based on point cloud data and structure engineering knowledge is established. Firstly based on the traditional ICP registration, combined with engineering professional knowledge, a point cloud registration algorithm that only uses relatively fixed points to participate in the registration process is proposed. This algorithm is used as the main body to construct a bridge spatial deformation identification method including point cloud segmentation, registration, deformation identification and result verification. At last, the whole set of methods is applied to an engineering example to efficiently obtain the change of geometrical profile of each component of the bridge within one year, and the structural engineering knowledge is used to verify the reliability of the identification results. The results show that the proposed point cloud registration algorithm based on engineering knowledge can efficiently realize the precise registration of two point clouds. The change detection method of geometrical profile of bridges based on this algorithm can quickly and accurately identify the spatial deformation of bridge components (e.g. bending and torsion of girders and lateral bending of piers) in a period of time. This proposed method can provide more technical means and practical experience for the intelligent non-destructive testing of bridges.