Due to the accumulation of manufacturing errors of components and construction errors, there are always deviations between an as-built complex tubular engineering structure (CTES) and its as-designed model. As terrestrial laser scanning (TLS) provides accurate point cloud data (PCD) for scanned objects, it can be used in the building information modeling (BIM) reconstruction of as-built CTESs for life cycle management. However, few studies have focused on the BIM reconstruction of a full-scale CTES from missing and noisy PCD. To this end, this study proposes an automated BIM reconstruction method based on the TLS for a full-scale CTES. In particular, a novel algorithm is proposed to extract the central axis of a tubular structure. An extended axis searching algorithm is applied to segment each component PCD. A slice-based method is used to estimate the geometric parameters of curved tubes. The proposed method is validated through a full-scale CTES, where the maximum error is 0.92 mm.
1 December 2020 in Journal of Constructional Steel Research
The hybrid coupled shear wall (HCW) with replaceable coupling beam (CB) is an optimal component to recover buildings promptly after a severe earthquake. However, the reinstallation may be difficult or impossible with an identical CB because of the inelastic relative dislocation between two wall piers. This study proposes a novel HCW with different reinforcement ratios in the connection, which was tested under cyclic loading. After the test, the bolt holes can be located through terrestrial scanning, which is then utilized to fabricate a new CB that can accommodate the deformation between two wall piers. The newly replaced HCW system was also tested. As a result, all virgin test specimens fail in web fracture and show a significant inelastic chord rotation of 0.2 rad, exhibiting an excellent energy dissipation capacity. Meanwhile, the new method to locate the bolt holes after the test is feasible. The replaced HCW fails in the pull-off of anchor bars and shows poor seismic behavior due to the unpatched concrete cover in the connection. To improve the energy dissipation for the replaced HCW, high-strength grouting in the connection can be used and high-strength material can be used to replace the usual anchor bolts.
As-built building information modeling (BIM) model has gained more attention due to its increasing applications in construction, operation, and maintenance. Although methods for generating the as-built BIM model from laser scanning data have been proposed, few studies were focused on full-scale structures. To address this issue, this study proposes a semi-automated and effective approach to generate the as-built BIM model for a full-scale space frame structure with terrestrial laser scanning data, including the large-scale point cloud data (PCD) registration, large-scale PCD segmentation, and geometric parameters estimation. In particular, an effective coarse-to-fine data registration method was developed based on sphere targets and the oriented bounding box. Then, a novel method for extracting the sphere targets from full-scale structures was proposed based on the voxelization algorithm and random sample consensus (RANSAC) algorithm. Next, an efficient method for extracting cylindrical components was presented based on the detected sphere targets. The proposed approach is shown to be effective and reliable through the application of actual space frame structures.