Regularized model for the prediction of compressive strain capacity of reinforced concrete shear wall boundary elements

Abstract

Laboratory tests of reinforced concrete (RC) rectangular prisms in compression were scarce in the literature before 2010. Between 2010 and 2020, there was a significant increase in laboratory testing of rectangular prisms motivated by field observations of flexural-compression failures in RC walls during the 2010 Chile (Mw 8.8) and 2011 New Zealand (Mw 6.2) earthquakes. The seismic behavior of relatively thin RC walls with flanges and subjected to high axial loads depends primarily on the effectiveness of the boundary element (BE) to resist high axial deformation demands without losing its load-carrying capacity. The confinement of the core mainly leads to the capacity of the BE. Therefore, the correct detailing and amount of transverse reinforcement in the cross-section is a crucial variable to consider; but this is not new because its impact on the response of RC prisms has been studied since 1929 by Richart. However, more recent studies have shown the relevance of another parameter, the damage zone length (HDZ). This study analyzes a database of experimental results of 45 rectangular RC prisms tested in the literature by Arteta, Mander, Welt, Massone, Taleb, and Tripathi. The empirical force-strain damage zone curves are estimated through a series spring model for specimens. Furthermore, several key parameters are fitted through regression to model the experimental response. A new auto-regularizing compressive capacity model is presented to estimate the performance within the damage zone in RC boundary elements based on its detailing and anticipated plasticity length. Model input data are at the designer’s fingertips: section geometry, longitudinal and transverse reinforcement ratio, compressive concrete strength, and yield strength reinforcement. The model provides the stress-deformation curve within the BE damage zone, which has the potential to extrapolate the response to different plastic hinge lengths and facilitate the design of reinforced concrete shear walls in structural design offices.