Analytical study of the response of reinforced concrete walls with discontinuities of flag wall type

Abstract

Slender walls with discontinuities at their bases, such as flag walls or walls with door openings or access, are common in Chilean practice because of the architectural requirements at facades, first floors, and underground levels. However, there is limited information about the behavior of such elements, and no designs or guidelines in the current codes consider the effects of discontinuities at the base. In this work, two analytical models are presented that estimate the yield displacement, yield curvature, and ultimate curvature of walls with openings, such as flag walls (setback), based on the dimensions of the opening and the longitudinal boundary steel ratio calibrated from a parametric analysis of a nonlinear finite element model. The results indicate that these discontinuities can have a major impact on the elastic displacement, reducing it because of the presence of a more rigid section above the opening, and also on the inelastic component, by increasing the curvature (and the strain) at the wall base because the opening tends to confine the plastic hinge within that area.