Inelastic wide-column models for U-shaped reinforced concrete walls

Although core structures are often used in reinforced concrete buildings as members providing lateral strength and stiffness, experimental and numerical studies on their inelastic behavior are scarce. In an experimental program recently completed at the ETH Zurich, two U-shaped walls were subjected to a bi-directional quasi-static cyclic loading regime. In this article, inelastic wide-column models for these two test units are developed. The wide-column analogy was chosen because it combines the merits of representing the U-shaped wall as a three-dimensional structure with inelastic properties while still being relatively simple and easy to set up when compared to shell or solid element models. It is therefore a tool which is not only available to researchers but also to design engineers. The article commences with the analysis of wide-column models that have been built according to recommendations found in the literature. Since these recommendations had been derived from analyzes of elastic systems, they are then revisited in a sensitivity study in which the effects of different modeling assumptions on the inelastic behavior of wide-column models are investigated. Finally, comparing the numerical results with the experimental evidence from the tests, the article concludes with practical recommendations for setting up wide-column models of U-shaped walls subjected to large inelastic deformations.