Mechanical Characterisation of GFRP Frame and Beam-to-Column Joints Including Steel Plate Fastened Connections

The study is part of the MOOVABAT project aiming at defining innovative technological buildings with low environmental impact and characterised by the capacity to constantly adapt to the changing of their users' needs. In this context, the mechanical performance of a fibre-reinforced polymer (FRP) frame, chosen as a structural solution for the building assembly, was investigated. Specifically, the research study aims to experimentally define the moment-rotation behaviour of screw-connected joints by using steel plates. For this purpose, two different configurations, a beam-to-column joint and a whole portal frame, were tested to evaluate the strength and the stiffness of the connection. In addition, the beam-to-column element was also subjected to cyclic loads to assess the joint energy dissipation capacity. The experimental results show that the strength of the connection is higher than that required to satisfy both serviceability limit state (SLS) and ultimate limit state (ULS) loading conditions. Moreover, it also provided an accurate characterisation of the semi-rigid connection useful for designing purposes and raising the possibility of considering an optimisation of the system. All in all, with respect to mechanical aspects, the study confirms the suitability of pultrude FRP element assemblies for modular building applications and paves the way for further analysis aimed at enhancing their efficiency.