Influence of steel fibers on the stress-strain state of the supporting sections of bending elements

The paper investigates the influence of steel fibers on the bearing capacity, deformability and fracture resistance of the supporting sections of bending elements. Beams of rectangular cross-section of two series-reinforced concrete beams of ordinary concrete and beams of combined reinforcement using steel fibers were considered. To make the specimens of the second series, steel anchored fibers were evenly added to the concrete, the total volume of which was 1% of the mixture volume. A special force bench was assembled to test the beams. During the tests, the load applied to the beams, deflections and deformations of individual concrete fibers were recorded. The load was applied in steps of 0.05 of the destructive load, the value of which was determined in the process of preliminary test loads. The carried out researches showed that the bearing capacity of the beams of combined reinforcement was practically by 50% higher than that of the conventional reinforced concrete beams. The breaking load in combined reinforcement beams is 162kN, and in conventional reinforced concrete beams 112kN. The deflections in steel-fibercrete beams by the time of failure are 1.4 times less than in reinforced concrete beams. The relative tensile deformations of concrete fibers in the shear span at the moment of failure are 3 times higher than those in the pure bending zone.