ASSESSMENT OF THE BEARING CAPACITY OF REINFORCED CONCRETE CORBELS TAKING INTO ACCOUNT THE DEFORMATION CHARACTERISTICS OF CONCRETE

Abstract

Modern methods of calculating reinforced concrete corbels under vertical load and potential opportunities for their improvement from the point of view of taking into account the deformation characteristics of materials are considered. The study demonstrates that commonly used models for assessing the resistance of reinforced concrete corbels are significantly simplified – both in terms of their geometric representation and in accounting for the deformation behavior of materials. The article analyzes the deformation characteristics of concretes of various strength classes, revealing potentially different failure mechanisms. Numerical simulations of corbel’s resistance are presented, including material nonlinearity and crack formation. These simulations reveal internal force trajectories that deviate from those predicted by conventional models and vary across different loading stages. The obtained trajectories are compared with those predicted by the Strut-and-Tie Model, which is widely applied in corbel’s resistance analysis. The paper highlights that current design standards recommend using a deformation-based model for reinforced concrete structures, which considers the complete compression and tension diagrams of concrete, the nonlinear behavior of reinforcement, and their combined deformation. However, the models currently in use do not account for the deformability of materials in any way. It is shown that, in addition to compressive strength, parameters such as the modulus of elasticity, tensile strength, and ultimate strains significantly impact the behavior of reinforced concrete corbels. The authors stress that conclusions regarding corbel’s resistance derived for one concrete class cannot be directly applied to structures made with concrete of a different class. This supports the need for further research into the influence of the deformation properties of both concrete and reinforcement when evaluating the bearing capacity of reinforced concrete corbels.