Cyclic Tests Performed on Real-Scale Squat Reinforced Concrete Shear Walls: Transition between Diagonal Shear and Sliding Shear Controlled Behavior Modes

Squat reinforced concrete shear walls are commonly used as primary gravity and lateral load–resisting systems in structures. Such low aspect ratio walls respond to load in diagonal or sliding shear. A series of real-scale quasi-static cyclic shear wall tests with identical geometry were conducted at the Multi-Axial Subassemblage Testing (MAST) facility at ETH Zürich to identify the influence of the axial load ratio and the steel reinforcement ratios on the transition between diagonal shear and sliding shear controlled behavior modes. Two specimens failed in sliding shear, and the other two failed in shear, either in diagonal compression or diagonal tension. The tests showed that squat walls exhibiting a sliding shear failure remain stable under the applied axial load even at displacements corresponding to 2% drift ratio. On the other hand, the walls that failed in diagonal shear did so in a brittle manner at displacements corresponding to 1% drift ratio. However, walls that slid had large residual displacements. The values of the shear wall axial load ratio and the longitudinal and horizontal reinforcement ratios at the transition between shear and sliding were identified.