Multilevel Computational Model for Failure Analysis of Steel-Fiber-Reinforced Concrete Structures

A multilevel modeling framework for the failure analyses of structures made of steel-fiber-reinforced concrete (SFRC), which allows researchers to follow the effects of design parameters such as fiber type, distribution, and orientation from the scale of fiber-matrix interaction to the structural behavior, is proposed. The basic ingredient at the level of single fibers is an analytical model for the prediction of the pullout response of straight or hooked-end fibers. For an opening crack in a specific SFRC composite, the fiber bridging effect is computed via the integration of the pullout response of all fibers intercepting the crack, taking anisotropic fiber orientations into consideration. For the finite-element analysis of the failure behavior of SFRC structures, interface solid elements are used to represent cracks. The softening behavior of opening cracks is governed by cohesive tractions and the fiber bridging effect. The use of an implicit/explicit integration scheme enhances the computational robustness considerably. Numerical analyses of selected benchmark problems demonstrate that the model is able to predict the structural response for different fiber cocktails in good agreement with experimental results. (C) 2016 American Society of Civil Engineers.