Experimental study of different fiber composites used to repair damaged coal gangue sintered brick masonry panels: Diagonal compression and cyclic shear compression behavior

Abstract

Fiber-reinforced composites represent one of the most effective technologies for seismic protection and post-earthquake damaged masonry structures in regions prone to seismic activity. However, existing masonry structures and post-earthquake damaged masonry structures may experience damage of varying severity, which seriously affects the effectiveness of fiber-reinforced composites. To elucidate the mechanisms through which various fiber composites enhance the shear and seismic resilience of damaged walls, comprehensive in-plane diagonal compression and cyclic shear tests were conducted on both masonry walls and confined masonry (CM) walls retrofitted with fiber-reinforced polymers (FRP), textile-reinforced concrete (TRC), and engineered cementitious composites (ECC). An analysis revealed that unreinforced and mortar-reinforced walls exhibited significant brittleness upon failure. In contrast, FRPs, TRCs, and ECCs considerably improved deformability while delaying the onset of cracking and stiffness deterioration. The efficiency of the FRP in enhancing the shear strength was slightly superior to that of the other two materials, whereas the ECC and TRC had comparable effects on improving the shear strength. Among the reinforced samples, those strengthened with ECCs presented the best ductility and energy dissipation capacity, whereas the FRP-reinforced samples presented the lowest ductility. The performance of the TRC-strengthened samples fell between those of the other samples. The investigation of diagonal compression revealed that the reinforced walls demonstrated significant enhancements in shear stress, initial stiffness, ductility, and energy dissipation compared to unreinforced walls, with improvements ranging from 19.9 % to 44.1 %, 8.1 %-30.5 %, 39.7 %-185.2 %, and 142.1 %-558.2 %, respectively. Additionally, in the context of cyclic shear compression, the reinforced walls exhibited improvements in peak load, ductility, and energy dissipation by 3.4 %-22.1 %, 24.5 %-100 %, and 66.9 %-180.8 %, respectively. Severely damaged CM walls reinforced with TRC and ECC met the requisite stability requirements under “large earthquakes,” whereas FRPs ensured stability only under moderate earthquakes. Pre-damaged CM walls reinforced with ECCs, TRCs, and FRPs can guarantee stability under conditions of large, moderate, and minor earthquakes, respectively.