Modeling of flexural behavior of SFRC : influence of constitutive law and mesh size

Fiber Reinforced Concrete (FRC) has been included in many national and international design code as a new structural material in recent years. FRC is a composite material with an enhanced post-cracking residual strength capacity. Design recommendations for FRC elements are based on post-cracking residual strength provided by fiber reinforcement. Steel Fiber Reinforced Concrete (SFRC) with small volume fraction of fibers usually shows post-cracking strain softening behavior. Strain softening with large displacement behavior is very complex phenomena to represent numerically. A plastic-damage based model included in Abaqus to analyze concrete structure has been used to simulate the behavior of SFRC. This plastic-damage model is capable of producing fair results for concrete structures. Unlikely concrete, SFRC has post-cracking residual strength capacity up to large displacement. Behavior of this model is checked with different stress-crack opening constitutive laws. Concrete Damaged Plasticity (CDP) model’s sensitivity to the variation of displacement has been checked by varying the post-cracking residual strength in such a way that represents a range of ultimate displacement from as small as normal concrete to the value when post cracking residual branch is almost horizontal. Finally, 3-point bending test on notched beams have been conducted to check how well the model can predict the structural behavior of SFRC elements.