Experimental Study of Seismic Performance of Masonry Walls Strengthened with CFN

Strengthening and repairing a building structure with a carbon fiber net(CFN)reinforcement system can improve its mechanical performance without changing the sizes of the component sections. To comprehensively evaluate the seismic performance of a masonry structure strengthened with CFN, we designed four non-rebar masonry walls and performed low-cycle reversed loading tests to investigate the effect of different reinforcement methods on the failure modes, bearing capacity, hysteretic curves, stiffness degradation, ductility, and energy dissipation capacity of the masonry structure. The results show that CFN reinforcement system does not peel off significantly when the reinforced walls are damaged, and it bonds and works effectively with the base of the wall. The damage modes differ for unreinforced and reinforced walls; unreinforced wall experience brittle shear failure, single-sided reinforced wall exhibit good ductile shear failure, and double-sided reinforced walls exhibit bending shear failure with excellent ductility. A CFN reinforcement system can effectively limit cracks and can inhibit the development of main cracks in the wall, ensures its integrity, and improves the reparability of the wall. Compared with unreinforced walls, the ultimate bearing capacity, ductility, and energy consumption of reinforced walls are improved significantly. The effect on double-sided CFN reinforced wall is the most significant, increasing the ultimate bearing capacity by 87.0% and the ductility coefficient by 52.2%, and the energy consumption capacity is the strongest at the same displacement in the later loading stage. Single-sided, double-sided and double-sided CFN reinforced walls with end anchoring have greater initial stiffness, i.e. 1.11, 2.38, 1.64 times that of an unreinforced wall, respectively. The stiffness of each reinforced wall has obvious lag compared with an unreinforced wall and the failure stiffness is greater than that of the unreinforced wall. The seismic effect of the double-sided CFN reinforced wall with end anchoring is stronger than that of the single-sided reinforced wall but weaker than that of the double-sided reinforced wall. These experimental results provide technical support for the engineering application of masonry structures reinforced with CFN. © 2019, Editorial Board of Journal of Tianjin University(Science and Technology). All right reserved.