Seismic retrofit of unreinforced masonry walls using precast panels of fiber-reinforced cementitious composite

Abstract

In this study, a practical seismic retrofit technique was developed for unreinforced masonry (URM) walls using precast panels of fiber-reinforced cementitious composites (FRCC). A hybrid fiber-type comprising steel and nylon fibers with a total volume fraction of 1% was adopted for fabricating the FRCC panels. A total of five URM walls were fabricated and tested under cyclic loading. The primary test parameters are the shear key types between precast panels and steel reinforcement details for the precast panels. From the test results, the URM walls retrofitted by precast panels with the proposed shear keys and reinforcement details showed a great improvement in terms of load-carrying and deformation capacity, stiffness degradation, and energy dissipation capacity compared to the control URM specimen. In addition, test specimens using additional reinforcement such as steel re-bars in the grooves of the panels and turnbuckles exhibited an increase of load-carrying capacity in both loading directions, in comparison with the counterparts without additional reinforcement. Eventually, a strength model was proposed to estimate the lateral strength of URM walls retrofitted by precast panels, and overall, its prediction indicates a good correlation in comparison with the experiment results.