Point Cloud Dataset and FEM for a Complex Geometry: The San Luzi Bell Tower Case Study

Detailed three-dimensional reconstruction of heritage objects is crucial for different purposes, such as analysis, preservation and maintenance, among others. Geomatics techniques allow acquiring complex and comprehensive information about geometry and current conditions of the surveyed objects in a short time, which is a great advantage for documentation and historical archives. The reconstruction of three-dimensional models is often performed using either image-based techniques, mainly Close Range Photogrammetry (CRP), including Structure from Motion approaches (SfM), or range-based techniques, such as Terrestrial Laser Scanning (TLS). These approaches have been widely applied in the field of Cultural Heritage to support multidisciplinary studies, from simple documentation to the monitoring of historical buildings, in restoration works or for structural analysis checks. The present paper aims at exploring the potential contribution of Geomatics to Structural Engineering, by investigating capabilities and advantages of TLS for a vertical structure. The experiments presented herein were carried out in a notable case study, the San Luzi church, located in Zuoz (Switzerland) in the Upper Engadin. Its bell tower is about 60 m high and is equipped with four bells. Strong vibrations caused by the ringing of the bells have been observed in the past, and a structural model was desired to enable numerical evaluations of the response of the tower to various load situations by FEM.