Reinforced concrete structural walls are common as the primary lateral load resisting system in modern mid- and high-rise buildings constructed in seismic regions, yet few research programs have investigated the seismic performance of modern, slender walls with nonplanar cross-sectional geometries. Three large-scale, C-shaped wall specimens, designed per ACI 318-08, were tested under uni- and bi-directional loading at the University of Illinois at Urbana-Champaign (UIUC). This paper presents experimental results including the cyclic load-deformation response and measured versus nominal flexural/shear strengths as well as a description of damage sequence. Final failure occurs due to a flexure-tension failure of boundary elements where multiple previously buckled bars fracture. From these tests, it is possible to conclude that with respect to uni- versus bi-directionally loading C-shaped walls have similar strong-axis load-deformation response until 0.75% drift as well as effective flexure/shear stiffness; however, there is a notable reduction in strong-axis ductility due to bi-directional loading. When comparing C-shaped walls to planar walls, the C-shaped specimens exhibit a more ductile flexural-tension controlled response where wall flanges contribute significantly to carrying compressive loads. Additionally, wall flanges and boundary elements are noted to be critical to resisting shear demands after the lightly-reinforced wall web has deteriorated.


Architectural Engineering

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URL: https://digitalcommons.calpoly.edu/aen_fac/128