Analysis of Shear-Critical Reinforced Concrete Beams

Recent experience among some researchers suggests that analysis methods based on the smeared rotating crack concept do not adequately model the response of shear-critical concrete beams containing little or no shear reinforcement. Application of the modified compression field theory (MCFT), one of the first such rotating crack models, to the analysis of shear beams is addressed herein. The original constitutive relations are reexamined, and a crack width limit and residual tension term are introduced. When incorporated into a nonlinear finite element procedure, the model is shown to adequately simulate the strength, stiffness, ductility, and failure mode of lightly reinforced shear-critical test beams. Sectional analysis procedures based on the same model are also shown to provide accurate predictions of response. Prevailing mechanisms are discussed, and aspects of the model in need of further refinement are also identified.