3D Laserscanning: Accurate geometry improving the safety assessment of masonry vaults

Why: The safety and stability of historical structures often is of key importance when dealing with a restoration project. The stability of masonry arches and vaults is directly related to their overall 3D geometry. Accurate knowledge of the geometry of ribs and vaults thus leads to better instruments for the assessment of their structural safety. Where or Context: 3D laser scanning has been applied within a pilot research project at the Sint-Jacobschurch at Leuven (B). The church is located in the heart of Leuven and has been closed down for the public since 1963 because of danger for collapse. Based on the 3D data of the point cloud captured, data-analysis provide the input data for the structural assessment, that is mainly based on the line of thrust methodology, captured within the software Calipous. When: Since masonry mainly behaves as a non-tension material, lines of thrust have to be found, lying within the cross section of the vaults. Therefore, the safety is directly related to the geometry itself and the analyses results strongly depend on the accuracy in which this geometry can be measured in practice. Effectiveness: The results demonstrate that the use of accurate 3D geometrical information can be transformed in an semi-automatic way into the required input results that are used for the safety assessment, Figure 1. Attention goes to the different phases to be addressed: gathering the point-clouds, 3D-modelling, structural analysis calculating thrust lines and the consolidation requirements that are obtained. The added value is in the capturing of accurate 3D-geometrical information without the need for scaffolding, nor touching the vaults and/ribs.status: publishe