A CONSTITUTIVE MODEL OF STEEL FIBER REINFORCED CONCRETE UNDER UNIAXIAL TENSION

The addition of randomly distributed short fibers in plain concrete can significantly improve the tensile properties. A modified smeared crack constitutive model for steel fiber reinforced concrete (SFRC) is proposed for the simulation of the mechanical behavior under uniaxial loading. In this model, a two-phase composite law is introduced to modify the elastic stiffness matrix. When the tensile cracking occurs, the model considers the plastic deformation as the interfacial slip displacement on the fiber and employs the bond-slip model to simulate the fiber-bridging behavior on the crack surface. The constitutive model is achieved by a Fortran code in the user subroutine Umat of the finite element software ABAQUS. The comparison between the numerical simulation results and experimental data under uniaxial tension shows that the new model can be used to simulate the SFRC characteristic behavior with good accuracy. By the numerical simulations, we further explore the influence of the SFRC related parameters and provide suggestions for the SFRC practical applications.