Cyclic Testing of T-shaped Moderate-Aspect-Ratio Shear Walls with High Strength Reinforcement

Six T-shaped moderate-aspect-ratio walls with high strength longitudinal and transverse reinforcement (in short HPTW) were tested to failure under reversed cyclic lateral loading. Primary test variables were wall aspect ratio, axial load ratio, and transverse reinforcement spacing. Experimental results were discussed and compared to T-shaped moderate-aspect-ratio shear walls with high strength transverse reinforcement (in short TW) in detail. For walls with aspect ratio of 2.15 and 2.80 mainly show the flexural-dominant mode; For walls with aspect ratio of 1.75 mainly exhibit bending-shear failure mode. Using high strength longitudinal reinforcement significantly improves the load-bearing capacity of walls, especially when web was in tension. Test results indicate that all the walls exhibited excellent ultimate deformation capacity, capable of sustaining a lateral drift ratio of 2.0-3.0% without significant loss of lateral strength, for the strong confinement effect of high strength transverse reinforcement. Sufficient attention should be paid to the design of the free web boundary elements to prevent premature failure in crushing of the concrete and buckling of longitudinal reinforcement. No special transverse reinforcement for concrete confinement is needed in the web-flange intersection. To maintain good ductility, for walls with design axial load ratio of 0.5 or aspect ratio less than 2.0, the volumetric steel ratio at the free web boundary should not be less than 1.50%. The results also indicate that the assumption of plan section remain plan after loading is suitable for the design of T-shaped moderate-aspect-ratio shear walls.