In-plane behavior of seismically damaged masonry walls repaired with external BFRP

This paper investigates the in-plane seismic behavior of eight unreinforced masonry (URM) walls before and after being retrofitted by basalt fiber reinforced polymer (BFRP). Among these eight specimens, one served as the reference specimen, without any strengthening scheme; three were directly strengthened with BFRP after construction; four were cyclically tested to the pre-defined damage level, and then repaired with BFRP. The mixed strengthening configuration was designed for the retrofitted URM walls. All these walls were tested to failure under a same loading strategy. Different parameters, including layer number, strip width, and vertical compression level, were considered in the laboratory tests. The experimental study shows that the failure modes between the reference specimen and retrofitted walls are different. Testing results are discussed in terms of lateral strength, ultimate drift, stiffness degradation, energy dissipation, and FRP strain. Finally, an improved design model is proposed for strength consideration of FRP retrofitted masonry walls.