Issue 60

A.-A. A. A. Graf et al., Frattura ed Integrità Strutturale, 60 (2022) 310-330; DOI: 10.3221/IGF-ESIS.60.22

Fig. 18 a) and b) show the behavior of ductility index and strength ratio with the increase in steel reinforcement ratio for control beams and confinement beams. The ductility index was calculated as the ratio between maximum deflections to the first cracking deflection. The strength ratio was calculated as the ratio between maximum loads to first cracking load. From data in figures we found that, at  min, the CFRP confinement technique enchases the ductility index more than steel fiber confinement technique. While at  avg and  max the steel fiber confinement technique gives more ductility than CFRP technique. On the other hand, the used confinement techniques were improved the strength ratio at all steel reinforcement ratios with obviously increasing in case of steel fiber.

N UMERICAL RESULTS

T

ab. 5 shows numerical results of 3-D FE models in this work for control models, C, carbon fiber reinforced polymers, CF, and steel fiber reinforced concrete, SF at four steel reinforcement ratios  min,  avg,  max, and    max. .

Pu (kN)

 u (mm)  74.40 33.91 20.65 18.99 50.12 32.00 14.46 15.25 72.25 55.42 33.33 22.61

Pcr (kN)

Failure mode 

 y (mm) 5.55 7.44 9.11 9.77 5.89 7.77 9.28 9.78 5.54 7.44 9.80 9.78

μ 

Beam code.

60.98 200.93 301.41 339.90 61.50 203.48 304.27 338.61 63.82 202.66 322.96 345.66

88.34 243.91 349.97 385.28 89.94 255.27 353.95 388.42 104.14 262.03 359.39 392.30

13.41 4.56 2.27 1.94 8.51 4.12 1.56 1.56 7.45 3.40 2.31 13.04

CC CC CC CC CC CC CC CC CC CC CC

C1 C2 C3 C4

CF1 CF2 CF3 CF4 SF1 SF2 SF3 SF4

CC Table 5: Numerical results of the FE Models. w here, P y and Δ y = yielding load and deflection, P u = ultimate load, Δ u = maximum deflection, μ = ductility index, CC = concrete crushing, and SF = shear failure.

Figure 19: Numerical load-deflection relationship for C1, CF1, and SF1 techniques at  min. .

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