Lessons learned from reinforced concrete wall tests

Nonrectangular reinforced concrete shear walls are often used in building systems as a means of resisting lateral forces. A collaborative research effort was conducted to investigate the behavior of nonrectangular wall systems subjected to multi-directional loading. The study included unidirectional tests on three rectangular walls to examine the effects of longitudinal reinforcement anchorage. This paper mainly discusses issues encountered in the design of the prototype T-shaped wall from a six-story office building assigned to Seismic Design Category D, and some of the outcomes of the tests. Design issues included investigation of critical biaxial loading combinations, distribution of design forces among individual walls, and detailing of the wall to comply with ACI 318-02 Building Code Requirements for Structural Concrete [1]. Test results confirmed the beneficial effects of eliminating lapped splices from plastic hinge regions, and the advantages of distributing vertical reinforcement, which include reduced shear lag and reduced crack widths in the wall section especially between the confined regions.