Unmanned Aerial Vehicle (UAV) and Building Information Modelling (BIM) Technologies in Concrete Dam Management: The Case of Ridracoli

Safety and proactive vision are key aspects for an efficient management of dams. The reduced accessibility and the large time needed for an inspection by traditional methods do not facilitate their direct visual inspection. Therefore, the use of Unmanned Aerial Vehicle (UAV) is suitable for this purpose, although the support of traditional topographic instruments (i.e. Total Station, GPS Station and Laser Scanner) is still necessary. The UAV survey provides qualitative information, with the aim of recognizing the condition of the materials (i.e. photos, videos), as well as quantitative information, with the aim of modelling the structure (i.e. geo-referenced dense point cloud). Since multidisciplinary aspects are involved in the management of dams, the possibility to share data (i.e. photos, videos) of every detail of the structure, also on different times and in different places, between a large number of specialists (i.e. engineers, architects, geologists, technicians, managers) allows for the effective and efficient resolution of problems. The UAV dense point cloud, integrated also with pre-existing data sets, is the base for the extraction of surfaces which describe important elements of the structure. The solid model is employed in Finite Element Method (FEM) analyses or, including additional information concerning volumes, mechanical characteristics, monitoring data, etc., it could be able to be the basis for a Building Information Modelling (BIM) of the dam system. The aim of the present paper is to explain the products of a UAV survey of a dam useful for storing and sharing information and for developing the starting point of a BIM of the structure. Case of study is the arch-gravity dam of Ridracoli, it has been the object of a technological comparison between traditional topographic instrument and the innovative UAV technique. The photo/video database captures the reference state of the structure and allows to investigate possible damage phenomena over time, moreover, by means of photomodelling technique, it provides the dense point cloud as a basis for a BIM.