Seismic performance of the ancient pagoda wall strengthened with GFRP bars embedded in the horizontal mortar joint under in-plane cyclic loading

The low strength and bonding of the mortar joints of the ancient pagoda wall result in the vulnerability to earthquake. To protect ancient pagodas under earthquakes, the seismic performances of the ancient pagoda wall strengthened with glass fiber reinforced plastic (GFRP) bars embedded in the horizontal mortar joint were studied. Six half-scale ancient pagoda wall specimens with semicircular arched openings, including two undamaged strengthened specimens, one severely damaged strengthened specimen, and three un-strengthened specimens, were tested under in-plane cyclic loading. The results indicated that the seismic performances of the strengthened specimens were effectively improved. Specifically, GFRP bars can effectively inhibit the generation of stepped cracks, and the failure modes of the strengthened specimens were changed from brittle shear failure to ductile shear failure. The shear bearing capacity of the strengthened specimens increased by 25% compared with the un-strengthened specimens. Moreover, the ultimate displacement, the energy dissipation capacity and the stiffness of the strengthened specimens were obviously increased. GFRP bars embedded in the horizontal mortar joint and glutinous rice mortar filled into mortar joint to strengthen the severely damaged specimen could effectively recover the seismic performance of the specimen. Furthermore, the calculation formulas of the shear bearing capacity of the strengthened ancient pagoda walls with semicircular arched openings were developed.