PSI - Issue 72

Serhii Drobyshynets et al. / Procedia Structural Integrity 72 (2025) 210–215

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The main investigated characteristics before failure were as follows: the strain of the extreme fiber in the compressed zone of steel fiber reinforced concrete was  sfb = 322×10⁻⁵; the strain of the tensile reinforcement was  s = 320×10⁻⁵; the beam deflections were f = 11.5 mm and f = 11.8 mm under concentrated forces, and f = 13.5 mm at mid span.

a)

b)

Fig. 2. (a) deformation graphs of beam B-1 (1 – steel fiber reinforced concrete, 2 – reinforcement); (b) deflection graph of beam B-1.

The beam failed along a normal cross-section due to the reinforcement reaching its ultimate strain. The deformation diagrams of steel fiber reinforced concrete and reinforcement for beam B-2 are shown in Fig. 3a, and the deflection graph is presented in Fig. 3b.

Fig. 3. (a) deformation graphs of beam B-2 (1 – steel fiber reinforced concrete, 2 – reinforcement); (b) deflection graph of beam B-2.

The behavior of beam B-3 was studied under repeated loading at a level of η = 0.9 over 20 loading-unloading cycles, with the beam being brought to failure on the 21st cycle. The beam withstood this loading-unloading regime and was intentionally loaded to failure in the 21st cycle. The load-bearing capacity of the beam was P u = 30 kN ( М u = 21 kN∙m). The main investigated characteristics before failure were as follows: the strain of the extreme fiber in the compressed zone of steel fiber reinforced concrete was  sfb = 325×10⁻⁵; the strain of the tensile reinforcement was  s