Issue 72

M. A. M. Khalil, Fracture and Structural Integrity, 72 (2025) 193-210; DOI: 10.3221/IGF-ESIS.72.14

Exp. Strain x 10^ -6 (mm) Analy. Strain x 10^ -6 (mm)

ε Exp. / ε Analy.

Specimen code

Type

Bottom flange ------- ------- -------

Top flange ------- ------- -------

Bottom flange ------- ------- -------

Top flange ------- ------- ------- 1080 1394 1862 1415 1415 1415

Bottom flange ------- ------- -------

Top flange ------- ------- -------

Avg. GFRP ------- ------- -------

Steel 2830 2830 2830 2830 2830 2830

Steel 2830 2830 2830 2830 2830 2830 2830 2830 2830

Steel 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00

RC1 RC2 RC3

Convention al Beams Internal Composite Beams External Composite Beams

RC1GI-I RC2GI-I RC3GI-I

1677 2463 2552 2486 2832 2629

989 1399 2042 1630 1189 1965

2426 2352 2607 2830 2830 2830

0.69 1.05 0.98 0.88 1.00 0.93

0.92 1.00 1.10 1.15 0.84 1.39

0.80 1.03 1.04 1.02 0.92 1.16

RC1GI-E 2830 RC2GI-E 2830 RC3GI-E 2830

Table 8: Comparison between experimental strains reading with the analytical values.

By comparing between the experimental results and the proposed theoretical equation of the composite section, the results is very closely to the yield moment, which indicating the reliability of the results that no significant differences in the yield moments were found as shown in Fig. 17 and Tab. 9 . The theoretical calculations and the precision of the proposed design were able to accurately predict the flexural behavior of composite and strengthened beams taking into consideration the value of the interface slip between GFRP profile and the concrete.

Figure 17: Comparison between experimental and theoretical yield moments.

Specimen code

Yield moments (M y ) (kN.m)

Type

M exp . / M theo .

M exp . 33.68 45.97 62.96 41.65 62.92 86.35 54.60 95.95 109.12

M theo . 31.56 46.52 64.95 42.47 65.39 86.10 53.99 93.34 107.35

RC1 RC2 RC3

1.07 0.99 0.97 0.98 0.96 1.00 1.01 1.03

Conventional Beams

Internal Composite Beams External Composite Beams

RC1GI-I RC2GI-I RC3GI-I RC1GI-E RC2GI-E RC3GI-E

1.02 Table 9: Comparison between experimental and theoretical results of beams.

C ONCLUSIONS

rom experimental and theoretical results on the flexural behavior of the proposed composite beams reinforced with steel bars and (GFRP) I-section, the following conclusions can be drawn : - Glass Fiber Reinforced Polymer (GFRP) I-section composite concrete beams proved to be an efficient F

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