Seismic behaviour of slender concrete walls with high-strength reinforcement

Twelve concrete walls with 500 MPa reinforcement and aspect ratios of 2.8 and 2.15 were tested under cyclic loading. Seismic behaviour was evaluated through analysis of failure characteristics, hysteretic curves, energy dissipation, and ductility. Results demonstrated that walls with an aspect ratio of 2.8 exhibited flexure-dominant failure modes, while those with an aspect ratio of 2.15 exhibited bending-shear failure modes. All specimens exhibited exceptional ultimate deformation capacity, sustaining a lateral drift ratio of 2.0% without obvious loss of lateral strength. Flanged concrete walls exhibited higher load-bearing capacity when the web was in compression, whereas better displacement ductility was achieved when the web was in tension. Compared with rectangular walls, flanged walls significantly enhanced strength and stiffness, but exhibited reduced ductility when the web was in compression. To ensure displacement ductility coefficients exceeding 3.0 for flanged walls with axial load ratios greater than 0.50 under web compression, the transverse reinforcement ratio at the free web boundary should surpass GB 50011-2010 requirements by more than 30%; however, the flange concrete remained intact without spalling, suggesting that the special confined reinforcement specified in GB 50011-2010 for flange ends was unnecessary.