Analysis of shear bearing capacity of hybrid steel fiber reinforced concrete deep beams

Abstract:

To investigate the shear mechanism of hybrid steel fiber reinforced concrete (HSFRC) deep beams, the effects of concrete, steel fiber, web reinforcement, and longitudinal reinforcement on the shear bearing capacity of HSFRC deep beams were taken into consideration, and steel fibers were incorporated into the tensile system of HSFRC deep beams. The calculation method for the shear bearing capacity of HSFRC deep beams was developed based on the softened strut and tie model (SSTM). Then, shear tests on four HSFRC deep beam specimens were conducted to evaluate the proposed method and further investigate the effects of steel fiber volume and web reinforcement ratio on the shear behavior of HSFRC deep beams. Results show that the designed procedure of the proposed calculation method was reasonable, which could accurately predict the shear bearing capacity of the specimens. The increase in the steel fiber volume could decrease the growth rate of the strain of HSFRC and increase the maximum strain of HSFRC. The web reinforcement ratio had little effect on the strain of HSFRC, but the increase in its volume could inhibit the development of the strain of reinforcement. The increase in the steel fiber volume could improve the bearing capacity, deformation capacity, and initial stiffness of the specimens. With the increase in the web reinforcement ratio, the shear capacity increased and the stiffness degradation was delayed, but the deformation capacity of the specimens first increased and then decreased.