Tension stiffening analysis of reinforced SFRC using mesoscale model considering the effects of cracking and localized rebar yielding

In this study, the tension stiffening behavior of steel fiber reinforced concrete (SFRC) with deformed rebar, was investigated based on mesoscale model named 3D rigid body spring model (RBSM). The steel hook end fibers (FIBER3D) were discretely modelled inside the Voronoi mesh of RBSM, and the local bond-slip model of deformed rebar was utilized to simulate the effects in normal concrete (NC) and SFRC. The contribution of steel hook end fibers was found superior to take the tension stiffening load in SFRC, by reducing the split cracks along longitudinal reinforcement of NC specimen instead forming the cross-sectional cracks along the cross section. The isolated peaks of rebar strain were found for SFRC with presence of cross-sectional cracks, while the expansive strain distribution with the split cracks were detected in NC specimen. The high local rebar strain induced the crack localization in SFRC specimen at the hardening zone while the high strength rebar found suitable to delay the crack localization in SFRC specimen. The controlled variation in fiber orientation (fibers oriented along the rebar axis and normal to the rebar axis) was found to be effective before yielding of the rebar especially in high fiber content like SFRC-1.0 %. The confinement due to large cross-section and fiber counts, was found effective to increase the load capacity and control the number of macro cracks. • Tension stiffening behavior of reinforced SFRC was investigated utilizing 3D RBSM. • Discrete steel fiber model coupled with RBSM, is capable enough to simulate the tension stiffening behavior. • The anisotropic cross-sectional cracking nature of SFRC, can be categorized from the analysis. • The anisotropy in cracking is fundamentally relies on the crack bridging characteristics of SFRC. • The fiber orientation and cross-sectional confinement influences the reduction of crack intensity in SFRC.