INfills and MASonry structures protected by deformable POLyurethanes in seismic areas (INMASPOL)

This project consisted of testing RC frames with a flexible joint made of polyurethane (PUFJ) with the masonry wall infills. The application of around 2 cm thick PUFJ reduces the stress concentrations at the contact and thereby reduces damage to infills and RC frames and improves the displacement capacity of the structural system. Furthermore, it offers additional amount of damping. Despite the flexibility of the polyurethane (PU), the bond between the PU and the other materials can transfer significant loads during in-plane and out-of-plane excitations. The PUFJ is versatile because different types of PU with very different stiffness, damping and strength characteristics can be used to manipulate the system dynamic behaviour. In case of premature out-of-plane flexural or in-plane diagonal tension infill failure, PUs can be used for bonding of various composite fibres to the weak masonry substrate to form Fiber Reinforced PU (FRPU) as well as for repair of damaged RC frames. The PU can cover emergency situations as it cures within hours and is easy to apply. The proposed project assessed the efficiency of the method through testing of full-scale infilled RC building on shake table. The seismic tests validated in-plane and out-of-plane infill performance when modified, repaired or strengthened with PUFJ and FRPU systems.