The use of 3D-laser scanning in assessing the safety of masonry vaults—A case study on the church of Saint-Jacobs

Safety and stability of historical structures are of key importance when dealing with a restoration project. The stability of masonry vaults very much depends on its overall geometry and the analysis results strongly depend on the accuracy in which this geometry can be measured in practice. To obtain an accurate estimate of the geometry of the vaults, 3D-laser scanning was performed. Based on the 3D-point cloud, a 3D-model of the vaults allows determining the lines of thrust in the structure as well as the reaction forces (application point and magnitude) at the abutments. This contribution gives a critical appraisal of the process used in the preliminary research phase: gathering the point clouds, 3D-modelling, structural analysis calculating thrust lines and the consolidation requirements that are obtained. The focus is on the added value of the methodology, its applicability, cost-effectiveness, overall advantages and drawbacks.