Applicability of Proposed Steel Fiber Model Based on 3D RBSM to Simulate the Mechanical Behavior of Steel Fiber Reinforced Concrete

The modeling of steel fiber reinforced concrete (SFRC) using computational methods become popular to understand the mechanical behavior of SFRC. In this study, a novel approach was adopted to model the steel fiber, discretely (SFRC model) coupled with 3D RBSM (Rigid body spring model). In 3D RBSM, the meshing technique is adopted the random geometry based Voronoi mesh design and the short fibers are inserted into the mesh interface with a zero sized fiber spring. In SFRC model, the smooth steel fiber was modeled by predicting a local bond-slip model and a spring component was considered to model the hook effects. Further, the estimated fiber load was divided into axial and shear components and the local matrix spalling, snubbing, and fiber rupture conditions were incorporated accordingly. Initially, the SFRC model was validated for single fiber pullout tests and the local bond stress found dominant for smooth steel fiber and the mechanical action for hook end fiber. The proposed model also reproduced the direct tensile behavior of SFRC with different volume of smooth and hook end fibers. The differences in post peak hardening capacity attributes the fiber orientation and matrix spalling as a deciding factor in mechanical performance of SFRC. The applicability of the model in structural level like tension stiffening of reinforced SFRC member, encountered the sufficient contribution of steel fibers in improving the tension stiffening capacity.