Issue 78

M. Adel et.al, Frattura ed Integrità Strutturale, 78 (2026) 168-185; DOI: 10.3221/IGF-ESIS.78.10

Figure 12: Effect of steel fiber on load-deflection behavior; deflection measurements were limited to a maximum of 13 mm.

Shear crack

Main crack

Tension crack

a) control beam, RC.

Main crack

b) control beam, RC-FRC.

Main crack

c) a/d= 0.25, TTC-RC-FRC.

Main crack

d) a/d= 0.25, MC-FRC-RC. Figure 13: Failure patterns of cracked and uncracked RC beams

Impact of MC against TTC on the Load- deflection response of RC beam For all tested beams, the MC beams exhibited larger peak and first crack loads than the TTC beams. Figs. 14a and 14 b illustrate the effect of the variation in load-deflection behavior between the MC and TTC beams for crack-to-depth ratios of 0.25 and 0.5, respectively. Both curves show an initial linear relationship with a steep rise in load with small deflection (elastic behavior) up to cracking loads. The data clearly indicate that the first cracking load of MC beams is higher than that of TTC beams. For a/d equal to 0.25, the cracking load for MC beams is 105 kN, while for TTC beams, it is 83 kN. After peak load, the TTC beams drop more sharply compared to the MC beams. The MC-RC-FRC curve maintains higher load

180