Experimental Behaviour of Fastener Strengthened Full Scale T-wall Under Out-of-Plane Loading

Recent earthquakes have demonstrated the vulnerability of unreinforced masonry buildings as the integrity of the structures is often affected by insufficient resistance of wall interconnections. Regarding the large share of masonry structures in the existing building stock, strengthening solutions increasing their seismic performance to achieve a box-like behavior are of highest relevance. This paper focuses on the strengthening technique using fasteners to strengthen wall intersections. Although the general technique is widely used, no detailed design approaches are available in scientific literature or codes. In order to fill this gap and support designers in their daily work, an experimental campaign on full scale masonry T-walls made of solid clay bricks using mechanical and bonded fasteners as strengthening method was carried out to develop a design concept, also considering recent developments in seismic qualification and design of fastenings to masonry. The specimens were built unreinforced with a weak connection at the orthogonal wall intersection and loaded out-of-plane until cracking and corresponding load drop. After that, the cracked wall intersection was strengthened using different fasteners with deep embedment bridging the cracks and cyclically loaded out-of-plane. The test results showed that a significant increase both in load capacity and ductility can be achieved depending on the type and number of fasteners used. The paper presents the main experimental findings.