PSI - Issue 81

Petro Gomon et al. / Procedia Structural Integrity 81 (2026) 411–416

414

а

b

Fig. 5. Failure modes of T-shaped reinforced concrete beams after exposure to low-cycle loading: а) Beam B-1.3; b) Beam B-1.4.

The results of beam tests are given in Table 3.

Table 3. Beam test results Beam number Load

Failure load, kN Beam deflection at 0.7 of the failure load, mm

Beam B-1.1 Beam B-1.2 Beam B-1.3 Beam B-1.4

Single load Single load Cyclic load Cyclic load

24.9 23.2 25.7 26.6

4.42 4.09

4.93 (10 cycle) 5.08 (10 cycle)

Strain diagrams (Figs. 6-7) demonstrate that strain stabilization in the extreme compressed concrete fibres occurs at the 6 th -7 th loading cycle , with the residual strains amounting to 5 16 10     b  . An increase in the flange thickness of the T-shaped flexural element leads to higher load-bearing capacity and a reduction in crack widths. As the flange thickness grows, the compressive strain in the concrete decreases. However, the concrete strengthening effect observed after the action of low-cycle loading diminishes with increasing flange thickness.

Fig. 6. Deformation diagram of the extreme compressed fibre of the T-shaped reinforced concrete beam (Beam B-1.3) under low-cycle loading (1st, 2nd, 5th, 10th, and 11th cycles)