Evaluation of the Nonlinear Behavior of Concrete Structures Using a Flat Shell Finite Element

Resumo

This work presents a study of the coupling of the geometric and material nonlinearities applied in

plain and reinforced concrete structures, using flat shell finite elements. For geometric nonlinearities, the prin-
ciple of virtual works and a generalized finite element method (GFEM) approximation are explored to directly

formulate the nonlinear governing equations in a total Lagrangian approach. The material’s behavior will be
described by a smeared cracking constitutive model, capable of representing the concrete degradation process,
from the phenomenological approach of crack propagation. In order to evaluate variations in stresses, strains,

and, consequently, degradation due to cracking along the thickness, the shell element is subdivided into N dis-
crete layers, allowing the measurement of the inelastic behavior of the material. In this proposal, each layer can

be represented by different materials, allowing the representation of reinforced concrete structures with the steel
described by a classic elastoplastic model. Finally, numerical simulations of shell structures will be presented,
considering the coupling of the referred nonlinearities.