Cyclic Behavior of Reinforced Concrete Structural Walls with Diagonal Web Reinforcement

A series of four reinforced concrete walls were tested to failure to evaluate the influence of diagonal web reinforcement on the hysteretic response. Two walls contained conventional horizontal and vertical web reinforcement, and two walls contained inclined web reinforcement. Reinforcement details were representative of construction practice in regions of low to moderate seismic risk. A single layer of web reinforcement was used, and the transverse reinforcement in the boundary elements did not confine the concrete core. Both walls with conventional web reinforcement failed due to web crushing. Pinched shapes characterized the hysteresis curves for top displacement and shear distortion near the base. In contrast, the walls with diagonal reinforcement displayed rounded hysteresis curves and failed due to crushing of the boundary elements. The choice of web reinforcement did not have a significant influence on the maximum lateral load resisted by the walls, but measured crack widths were less, and more energy was dissipated by the walls with diagonal reinforcement during loading cycles with comparable levels of displacement. Analytical results from finite element analyses also indicated that the diagonal web reinforcement was effective in transferring shear force to base of walls, especially during load reversals when most diagonal cracks in concrete remained open and compressive struts in concrete were not effective in transferring shear force.