Issue 63

A. Kh. Elbaz et alii, Frattura ed Integrità Strutturale, 63 (2023) 257-270; DOI: 10.3221/IGF-ESIS.63.20

120

100

80

60

Load (KN)

40

20

0

B1

B2

B3

B4

B5

Pmax (exp.) Pmax (num.)

96,434 97,102

89,1

87,85

83,1

77,81

88,232

90,697

84,878

80,965

Figure 16: Comparisons between failure loads of the experimental and FE final loads for all beams.

10 15 20 25 30 35 40 45 50 Deflection (mm)

0 5

B1

B2

B3

B4

B5

Max DEF. (exp.) Max DEF. (num.)

36,911 44,915

42,574 27,764

41,256

39,397 44,298

34,512 40,448

45,31

Figure 17: Comparisons between max deflection of the experimental and FE for all beams.

C ONCLUSIONS

 The ultimate capacity of the tested beam (B2) induced by damage presented as a gap in the concrete mold decreased by 7.6% compared to the control beam (B1). It can be concluded that the presence of voids in the concrete mold decreases the ultimate load and the tensile steel strain while it increases the deflection and concrete compressive strain.  The ultimate capacity of tested beams (B3, B4 and B5) induced by having a mild steel at middle bottom reinforcement with variable length from 250 mm to 1000 mm decreased by 8.9 %, 13.82% and 19.31% respectively than control beam (B1). It can be concluded that increasing mild steel length at middle bottom reinforcement decreases the ultimate load, stiffness, deflection and the tensile steel strain while it increases the concrete compressive strain of static cyclic loading tested beams.  It is essential that RC beams which are subjected to any type of failure result in significant ductility gain, mainly if the failure mode is premature, such as debonding or flexure failure.  The numerical results of the tested specimens demonstrated similar key conclusions to the experimental ones; the finite element models are shown to accurately predict the structural behavior of RC beams under static cyclic loading deviations varying no more than 4 % for all specimens.

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