Knowledge of Different Roofing Systems in the Politecnico di Milano: Geometric Survey and Material Investigation

The paper presents a study carried out on the roofing system of Politecnico di Milano main Campus, a public complex that was built at early XX century and is a relevant part of a valuable architectural heritage. The research was aimed at its structural and health assessment as a first step for designing its subsequent safeguard intervention. The adopted method of analysis consisted of different phases that started from a photographic and 3D direct geometric survey of the trusses that span over large rooms and sometimes bear brickwork vaults hanging below. Material, morphological and constructive aspects of the roofing systems were analyzed also comparing the different building solutions adopted in the different parts of the construction; a recognition of the types of connections between the hanging devices and timber trusses was carried out as well. According to the current Technical Codes, direct inspection of the structural elements was performed in order to collect the following information: macroscopic determination of the timber species, determination of their natural durability, individuation and technological evaluation of the principal defects and alterations, individuation of the pre-existing or still present macroscopic pathologies, sample detection of the ambient conditions and of the timber humidity through non-destructive measurement by electronic thermo-hygrometer. Where needed, drilling tests were applied in the deteriorated or suspected zones and an estimate of the residual sections was achieved, as well as the identification of two different use classes. Considerations on the reliability and recoverability of the inspected timber components were then made possible.