Nonlinear response modeling of low-rise structural walls

Abstract

A nite element modeling approach was validated and improved in this study, for simulating the behavior of reinforced concrete structural walls with aspect ratios of 1.0 or less, whose behavior is governed by shear deformations as well as interaction between shear and exural responses. To validate the model, a total of fteen squat structural walls were calibrated and analyzed using Matlab. Mechanisms of shear aggregate interlock in concrete and dowel action on reinforcing bars were explicitly incorporated in model formulation, and cyclic degradation parameters associated with these mechanisms were implemented in model for better representation of the in-plane hysteretic lateral load behavior of squat structural walls. The e ect of strain penetration within the wall foundation was considered in the model predictions, to capture the initial sti ness and lateral load capacity of the walls in early drift levels more accurately. Re ned constitutive models were used in the model formulation to represent the hysteretic stress-strain behavior of reinforcing steel and concrete. Features of the experimental conditions, such as loading under double-curvature or single-curvature, or presence of a weakened plane joint in the wall, were represented in the model calibration and analysis conditions. Analytical predictions of the lateral load vs. displacement responses obtained using the nite element model were compared with the experimental measurements. Comparisons revealed that the model reasonably predicts the overall lateral load vs. displacement behavior, as well as important response attributes such as the initial sti ness, lateral load capacity, cyclic strength and sti ness degradation, and pinching characteristics of the walls investigated. While subject to further re nement, the analytical model in its current improved form is shown to be a feasible candidate for simulating the hysteretic lateral load behavior of squat structural walls.