Shear-dominated failure in reinforced concrete (RC) members remains difficult to predict numerically due to its brittle nature and the limited ability of conventional constitutive models to represent shear-induced damage mechanisms. Classical formulations based on the Menetrey–Willam surface for compressive behavior and Rankine-type criteria for tensile cracking primarily address flexural and compressive failure modes, often providing limited insight into shear localization and abrupt strength degradation. This contribution proposes a comparative numerical investigation between a research-oriented multisurface elastoplastic concrete model incorporating an explicit shear failure mechanism and the commercial finite element software DIANA, which relies on a total strain crack modeling framework. The study is designed to evaluate how different constitutive assumptions influence the numerical simulation of shear-dominated behavior in RC members. The comparison will be conducted on two experimentally tested shear-critical specimens: a short RC column subjected to constant axial load and monotonic lateral displacement, and a wide RC beam designed to fail in shear under monotonic loading. Identical geometry, boundary conditions, and material properties reported in the experimental studies will be adopted in both numerical frameworks to ensure a consistent basis for comparison. The focus of the investigation is on assessing the capability of each modeling approach to represent shear-related mechanisms, including tensile cracking, shear transfer across cracks, and compressive softening, as well as their implications for failure localization and numerical stability. By systematically contrasting a multisurface elastoplastic formulation with a widely used commercial modeling approach, the study aims to clarify the role of constitutive modeling choices in the numerical assessment of shear-critical reinforced concrete members.