T-Shaped RC structural walls subjected to multidirectional loading: Test results and design recommendations

Two T-shaped reinforced concrete wall specimens were subjected to reversed cyclic loading quasi-statically to failure. Both represented half-scale wall assemblages of a 6-story prototype building. Modifications to the wall detailing were incorporated to study the effects of longitudinal reinforcement distribution and splicing, shear lag, increased amounts of shear reinforcement, and increased dimensions of the boundary elements beyond original code-based requirements. In addition, the minimum number of stories required to capture important aspects of multi-story wall behavior through physical experiments was investigated. Distributing the longitudinal reinforcement across the flange, rather than concentrating it within the boundary elements, was found to reduce crack widths, damage to the wall, and shear sliding across the wall panel. Concentrating large amounts of reinforcement in the flange tips tended to increase shear lag effects in the web-direction loading, but led to moderate increases in the in-plane strength and deformation capacity in the flange direction. Locating the lap splices at the second-story level avoided problems with localized damage observed in cases where lap splices are located at the wall-flange interface. Increasing the amount of shear reinforcement and dimensions of the boundary elements did not have a significant impact on behavior. A minimum of two stories was found to be necessary to characterize the behavior of this 6-story prototype structure; it was sufficient to capture the height over which plasticity occurred.