PSI - Issue 47

Shakiba Zolfaghari et al. / Procedia Structural Integrity 47 (2023) 398–407 S. Zolfaghari et al./ Structural Integrity Procedia 00 (2019) 000–000

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The specimens strengthened through the EBROG method showed a 12.5 to 53.7% increase in the debonding load compared to the specimens strengthened through the EBR method (Table 1). Specimens EBROG-15×15, EBROG-5×10, and EBROG-10×5 showed the highest debonding load with a debonding load of 12.30, 11.98, and 11.67 kN, respectively. Considering that the volume of the groove in specimen EBROG-15×15 is 4.5 times that of the other two specimens and it showed only 5.4 and 2.7% more load compared to them, so it is not considered as the optimal economic groove. Two specimens EBROG-5×10 and EBROG-10×5, which have the same groove volume, do not have a significant difference in the amount of debonding load, and both can be considered as optimal grooves with the approach of debonding load as the bond strength. The effect of groove width variation on the FRP-concrete bond debonding load for the groove depths of 5, 10, and 15 mm can be seen in Figs. 4(a-c) and Table 4. At the groove depth of 5 mm (groove widths of 2.5, 5, 10, and 15 mm), with the increase of the groove width from 2.5 to 10 mm, the debonding load increased from 10.1 to 11.67 kN and then by increasing the groove width to 15 mm, it decreased to 11.15 kN. That is, the optimum groove width corresponding to the groove depth of 5 mm is 10 mm (Fig. 4(a) and Table 4). At the groove depth of 10 mm (groove widths of 5, 10, and 15 mm), with the increase of the groove width from 5 to 10 mm, the debonding load decreased from 11.98 to 9.33 kN and then by increasing the groove width to 15 mm, it increased to 11.2 kN. That is, the optimum groove width corresponding to the groove depth of 10 mm is 5 mm (Fig. 4(b) and Table 4). At the groove depth of 15 mm (groove widths of 5, 10, and 15 mm), with the increase of the groove width from 5 to 15 mm, the debonding load increased from 9.94 to 12.3 kN. That is, the optimum groove width corresponding to the groove depth of 15 mm is 15 mm (Fig. 4(c) and Table 4).

Groove depth = 10 mm

Groove depth = 15 mm

Groove depth=5 mm

12,3

10 15

10 15

11,98

11,67

11,2

10 10,5 11 11,5 12

9,94 10,54

9,33

11,15

0 5

10,27

0 5

10,1

0

10

20

0

10

20

0

10

20

Debonding load (kN)

Debonding load (kN)

Debonding load (kN)

Groove width (mm)

Groove width (mm)

Groove width (mm)

(a) (c) Fig. 4. Effect of groove width variation on the FRP-concrete bond debonding load: (a) groove depth = 5 mm; (b) groove depth = 10 mm; (c) groove depth = 15 mm. (b)

The effect of groove depth variation on the FRP-concrete bond debonding load for the groove widths of 2.5, 5, 10, and 15 mm can be seen in Figs. 5(a-d) and Table 4. At the groove width of 2.5 mm (groove depths of 2.5, 5, and 7.5 mm), with the increase of the groove depth from 2.5 to 5 mm, the debonding load increased from 9.7 to 10.1 kN and then by increasing the groove depth to 7.5 mm, it decreased to 9 kN. That is, the optimum groove depth corresponding to the groove width of 2.5 mm is 5 mm (Fig. 5(a) and Table 4). At the groove width of 5 mm (groove depths of 5, 10, and 15 mm), with the increase of the groove depth from 5 to 10 mm, the debonding load increased from 10.27 to 11.98 kN and then by increasing the groove depth to 15 mm, it decreased to 9.94 kN. That is, the optimum groove depth corresponding to the groove width of 5 mm is 5 mm (Fig. 5(b) and Table 4). At the groove width of 10 mm (groove depths of 5, 10, and 15 mm), with the increase of the groove depth from 5 to 10 mm, the debonding load decreased from 11.67 to 9.33 kN and then by increasing the groove depth to 15 mm, it increased to 10.54 kN. That is, the best groove depth corresponding to the groove width of 10 mm is 5 mm (Fig. 5(c)