In-situ testing of the out-of-plane flexural behavior of hollow block masonry walls retrofitted with steel fiber reinforced mortar coating

The present work focuses on the discussion of the experimental results of three monotonic and quasi-static reverse cyclic tests performed to assess the out-of-plane behavior of hollow clay block masonry walls strengthened with coating. The latter consisted of a single 30 mm thick layer of mortar applied on the outer surface of masonry and reinforced with short (32 mm long) high strength steel fibers randomly spread within the mortar matrix. Compared to traditional laboratory tests, the ones conducted herein can replicate the actual boundary conditions occurring in actual structures as the test walls are part of a full-scale building tested in previous research. The test results provided insights into the stiffness, ductility, flexural and energy dissipation capacity of the walls. Additionally, considerations regarding equivalent viscous damping were also reported. Finally, using a classical arch thrust resisting model, an analytical evaluation of the out-of-plane flexural resistance of the unstrengthened walls was conducted to assess the potential out-of-plane strength improvement achieved through a coating of steel fiber reinforced mortar.