Observed damages in reinforced concrete wall buildings following some recent earthquakes raised concerns about the seismic performance of rectangular RC walls. Damages in RC walls included spalling and crushing of concrete and longitudinal reinforcement buckling at boundaries as well as global buckling. Preliminary studies attributed these damages to the lack of adequate confinement and detailing in wall boundary regions and high axial load level. Prism specimens representing wall boundaries were tested to study the influence of reinforcement detailing, cross-section slenderness, and loading type on the damages, failure modes, and compressive capacity of isolated confined boundary regions of RC rectangular walls. It was found that the tensile strain prior to compressive strain affected the performance of thin wall boundaries and may lead to different failure modes when subjected to cyclic loading. It was also found that dense transverse reinforcement detailing in thin confined boundaries did not improve their compressive capacity. Design and detailing rules to prevent global buckling and reinforcement bar buckling were also evaluated. A Numerical model that takes into account buckling of reinforcement was proposed to simulate response curves of cyclically tested specimens. The model showed the influence of reinforcement buckling behavior on reducing the compressive capacity for elements with buckling of reinforcement failure.

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For accurate assessment of performance levels in reinforced concrete (RC) members, it is important to well define deformation limits at particular damage states. For RC walled building, investigation of the deformation limits of RC structural walls is required to define limit states and corresponding limiting values. Numerical investigations were carried out on barbell shape and rectangular RC walls with confined boundaries to evaluate response curves and ultimate deformations. A nonlinear 2D and 3D finite elements (FE) models were built in order to simulate the load-deformation relations under monotonic loading as well as cracking and damage patterns of previously tested walls. The FE models were able to simulate the backbone curves with good accuracy as well as the ability of boundary columns in reducing damage level. The 3D FE model simulated very well the ultimate deformation compared to 2D models. A sectional fibre model combined with plastic hinge length and shear deformation component is proposed in order to simulate the backbone curves and the ultimate deformation with less computational cost compared to 3D FE analysis. The model was able to provide relatively accurate backbone curves with very good estimation of ultimate drift.

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