Determination of the behavior of steel fiber reinforced concrete beams without stirrups under bending by nonlinear finite element analysis

Abstract

Although the use of steel fiber reinforced concrete elements is on the rise in recent years, present analytical models to determine the structural behavior of these members are inadequate, requiring numerical methods such as nonlinear finite element method. In this study, two steel fiber reinforced concrete beam and one ordinary reinforced concrete beam tested under static three-point bending were modeled with a Modified Compression Field Theory based nonlinear finite element method and results were investigated. In the method, Simplified Diverse Embedment Model was selected to model the tensile stresses transmitted between crack faces in cracked concrete. When analysis results were compared with experimental results, it was observed that the bending capacities and major cracks were captured with high accuracy, whereas displacement capacities were highly underpredicted. Although the major cracks were predicted with high accuracy, the fact that the model could not predict smaller cracks accurately and, as a result, the occurrence of a premature reinforcing bar failure at major cracks is believed to be the major reason for earlier failure of beams. More advanced models are needed for modeling the steel fiber reinforcement in order to obtain more accurate solutions.