Rotational springs for localized crack modeling in structural concrete

Abstract

This paper presents a mechanical and numerical approach to model localized deformations occurring in concrete structures with less than minimum reinforcement. The presented models are based on, and validated against large‐scale experiments conducted in a previous study to investigate the behavior of a less than minimally reinforced slab in the framework of the structural safety assessment of an existing cut and cover tunnel. The model deploys rotational springs embedded in a nonlinear finite element analysis to capture deformations concentrating in an inclined crack. An iterative solution procedure ensures equilibrium and compatibility in the inclined crack section by adjusting the spring stiffnesses, which depend on the acting loads. A case study shows that the localized crack has a minor effect on the global structural behavior. In contrast, localization strongly influences deformations and stress resultants in the crack, and compressive membrane action significantly impacts the load–deformation behavior of the localized crack, which is relevant particularly for the shear strength.