Sophisticated mathematical models as well as solid experimental data are required to assess the safety of ancient vaults, e.g., in churches.
At the University of Wismar an experimental vault (Fig. 1) was built. Increasingly higher loads were applied until structural collapse (Fig. 2). In addition to strain gauges and displacement transducers photogrammetry was used to measure displacements.
Several hundred affordable printed photogrammetric markers were attached to the vault. Up to 400 pictures in about 45 minutes were taken from various perspectives using a movable platform. The camera positions are shown as gray dots in Fig. 3. For each load level a 3D point cloud was created. Using the advanced analysis algorithms of the Linearis3D Photogrammetry system the point clouds were matched and visualized in two (Fig. 4) and three (Fig. 3) dimensions.
Photogrammetry made it possible to measure the three dimensional displacement of an arbitrary number of points at very low cost and installation effort. Optical measuring technology contributed substantially to the overall success of the project.
We would like to thank Prof. Dr.-Ing. Bernd Guericke and Dr. Rabe as well as the students from Wismar University. More information on the project is available here.
We will advise you on which measured values matter — and recommend the right system.
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