Tying facades of masonry buildings. Preliminary experimental results on fuse-based solutions

Vintage unreinforced masonry constructions, without proper connections to transverse structures, can suffer from out-ofplane failures when subjected to earthquakes. The most common way to prevent these mechanisms is to strengthen the facades by means of steel tie rods. Experiments available in the literature have shown that this solution may develop limited ductility due to the threading necessary for installation and tightening. To increase ductility and to simplify replacement in case of damage a fuse-based solution is proposed. A sacrifice element, made of one of two alternative plastic materials, is connected to carbon-steel rods by means of threaded turnbuckles. Two diameters and two unengaged threaded lengths are considered. The preliminary experimental results are presented, together with material testing on unthreaded steel and plastic bars. The ductility observed in the smooth plastic samples is reduced by the threading but some degree of ductility remains, somewhat larger than what reported for carbon steel.