Modeling of coupled nonlinear shear and flexural responses in medium-rise RC walls

Abstract

A macroscopic nite element modeling approach was adopted in this study for simulating the in-plane hysteretic lateral load behavior of medium-rise reinforced concrete structural walls with moderate aspect ratios (1.5 and 2), with coupled nonlinear exural and shear response components. The constitutive formulation of the model is based on a xed-crack-angle modeling methodology. Improvements were made on the constitutive model formulation, for better representation of the shear-aggregateinterlock e ects in concrete,and dowel action on reinforcing bars, constituting the shear stress transfer mechanisms across the cracks. The model formulation was implemented into Matlab and analyses were performed using a drift-controlled nonlinear analysis solution strategy. The model was extensively calibrated for ve heavily-instrumented wall specimens with moderate aspect ratios (1.5 and 2), and model predictions were compared with experimentally-measured responses at both global and local response levels. Response comparisons revealed that the model provides reasonably accurate predictions of the lateral load capacity, sti ness degradation, hysteretic shape, ductility, and pinching characteristics of the wall specimens investigated. The model also provides reasonable estimates of the relative contribution of exural and shear deformations to wall displacements, longitudinal strain pro les and rotations along the base of the wall, and crack orientations. Sensitivity studies were also conducted to evaluate the variation of the analytical results with model parameters. The modeling approach implemented in this study is believed to be a signi cant improvement towards reliable prediction of the coupled shear- exural response of reinforced concrete walls under cyclic loading conditions.