Amirkabir University of Technology Amirkabir Journal of Civil Engineering 2588-297X 53 6 2021 08 23 Experimental and numerical investigation of the effect of steel fiber on fiber reinforced concrete under multiaxial compression Experimental and numerical investigation of the effect of steel fiber on fiber reinforced concrete under multiaxial compression 2657 2678 3996 10.22060/ceej.2020.17462.6576 FA Gholamreza Baghban Golpasand Department of Structural Engineering, University of Tabriz, Tabriz, Iran غلامرضا Farzam Department of Structural Engineering, University of Tabriz, Tabriz, Iran Siamak Soleymani Shishvan Department of Structural Engineering, University of Tabriz, Tabriz, Iran Journal Article 2019 12 07 Concrete is one of the most widely used building materials in the world and the use of fiber-reinforced concrete (FRC) in structures to increase its tensile strength and improve its behavior has been extensively developed in recent decades. It is necessary to determine the constitutive equations of FRCs when the numerical investigation of their behavior is running. These equations should be including relations to handle the effect of steel fibers on the behavior of FRC. In this study, the behavior of FRCs with a different percent of steel fiber under triaxial compression, with different values of confining pressure, is experimentally and numerically investigated. Hoek cell is used in triaxial tests. In the numerical simulation, five-parametric constitutive equations with Willam-Warnke (W-W) failure criterion, isotropic hardening/softening function and non-associated plasticity were used and substepping integration method was carried out for integration of constitutive equations. For applying the effect of steel fibers on the failure surface, Kt coefficient was determined from the results of biaxial experimental tests on SFRCs. The constitutive equations are implemented with UMAT subroutine in ABAQUS and specimens are simulated in ABAQUS. By the comparison of the experimental (maximum strength) results and the numerical (stress-strain curve) results, an acceptable agreement was seen between them. Finally, based on the consistency between experimental and numerical results, it was concluded that the numerical model could be used, with enough confidence, to predict the behavior of SFRCs specimens. Concrete is one of the most widely used building materials in the world and the use of fiber-reinforced concrete (FRC) in structures to increase its tensile strength and improve its behavior has been extensively developed in recent decades. It is necessary to determine the constitutive equations of FRCs when the numerical investigation of their behavior is running. These equations should be including relations to handle the effect of steel fibers on the behavior of FRC. In this study, the behavior of FRCs with a different percent of steel fiber under triaxial compression, with different values of confining pressure, is experimentally and numerically investigated. Hoek cell is used in triaxial tests. In the numerical simulation, five-parametric constitutive equations with Willam-Warnke (W-W) failure criterion, isotropic hardening/softening function and non-associated plasticity were used and substepping integration method was carried out for integration of constitutive equations. For applying the effect of steel fibers on the failure surface, Kt coefficient was determined from the results of biaxial experimental tests on SFRCs. The constitutive equations are implemented with UMAT subroutine in ABAQUS and specimens are simulated in ABAQUS. By the comparison of the experimental (maximum strength) results and the numerical (stress-strain curve) results, an acceptable agreement was seen between them. Finally, based on the consistency between experimental and numerical results, it was concluded that the numerical model could be used, with enough confidence, to predict the behavior of SFRCs specimens. https://ceej.aut.ac.ir/article_3996_43e04dd08bb1305428b0c9c8d8a2660a.pdf