Effects of sectional kinematic constraints in fiber element formulations on the load‐deformation response of reinforced concrete elements

Abstract

Developing numerical tools for reinforced concrete elements accounting for the axial-flexure-shear interaction is important as their brittle failures may lead to a complete collapse of structures. Among the different numerical tools available, fiber element formulations are enforced with kinematic constraints for the sectional strain fields. This study aims to investigate the impact of such kinematic constraints in fiber element formulations towards the response of reinforced concrete elements. A series of beams selected from literature was analyzed using available numerical tools, and the global and local responses were compared. In the postcracking branch, the fiber element formulations result in an underestimation of the shear strain distribution in the tensile zone which leads to an overprediction of the postcracking stiffness. In addition, the load carrying capacity and failure mode predictions of the fiber element formulations were proved to be accurate despite the underestimation of shear strains in the tensile zone.