Cyclic Test on a Full-Scale Unreinforced Masonry Building Repaired with Steel Fiber-Reinforced Mortar Coating

The present work reports the results of two quasi-static reverse cyclic tests performed on an unreinforced hollow clay block masonry building before and after repairing with a single 30-mm thick layer of mortar applied on the façades. Unlike traditional coating-based retrofitting techniques, the one proposed herein adopts a cement-based mortar reinforced with short high-strength steel fibers randomly diffused in the mortar matrix. In order to assess the effectiveness of the strengthening intervention, a preliminary cyclic test was carried out on the unstrengthened building in order to predamage masonry. The experimental results showed that the repaired structure exhibited a significant improvement of seismic behavior both at the serviceability and ultimate limit state conditions. Moreover, based on the observed ultimate ductility of the retrofitted building, some considerations on the behavior factor are reported.