Precast TRC sandwich panels for energy retrofitting of existing residential buildings: full-scale testing and modelling

In the 7th Framework Programme for Research and Technological Development, the European Commission financed the project EASEE (2012–2016), which was aimed at developing façade solutions for the energy retrofitting of multi-storey multi-owners existing residential buildings, built in an historical period in which no specific attention was paid to the energy issue. For the outer envelope, the consortium proposed textile reinforced concrete precast sandwich panels. The high durability, high aesthetic potential, low impact on occupant life during installation, and increase in impact resistance make this solution competitive with the exterior insulation and finishing system, now the most widespread energy retrofitting method adopted on existing buildings. Within the project, the panel has been mechanically investigated at multiple scales, and finally applied on some demo-buildings. This paper presents the investigation of the bending behavior of full-size panels up to failure when tested according to four-point bending scheme, focusing the attention on the effects of the production procedure and panel details on the structural behavior. The capability of expanded polystyrene in transferring shear stresses to the external TRC layers—already exhibited by specimens at lab-scale—is here verified on full-size elements. In addition, a numerical model—already validated for lab-scale sandwich beams—is here applied in order to check its reliability for the design of full-scale panel