Issue 38

I. N. Shardakov et alii, Frattura ed Integrità Strutturale, 38 (2016) 331-338; DOI: 10.3221/IGF-ESIS.38.43

3. The onset of delamination of CFRP sheet corresponds to the bending moment, which is 75% of the limit value. Thus, the presence of delamination does not determine the limiting state of CFRP beams with anchorage of CFRP tape on the bearings. Therefore, it is possible to use the breaking strain of the composite as a limiting value of deformations in the limit state design. The existence of cohesive delamination does not reduce the stiffness of the reinforced structure.

The relative area of the delamination, %

CFRP strain, με

Specimen

Binary card of defects

particular value

Average value

7.8

10300 10660 10140 10280 8020 10240 10810 10200 10070 8970 7220 10450

B1b-3 B1b-4 B1b-5 B1c-1 B1c-2 B1c-3 B2b-3 B2b-4 B2b-5 B2c-1 B2c-2 B2c-3

12.99 8.34 19.77 22.59 26.43 11.78 20.18 12.73 17.86 33.08 46.29

9.71

22.93

14.90

32.41

Table 3 : The results of static tests of beams of series C.

Figure 5 : The comparison of experimental and theoretical values of deformations corresponding to the onset of cohesive delamination.

A CKNOWLEDGMENT

This research was supported by the Russian Science Foundation, project No. 14-29- 00172.

R EFERENCES

[1] Teng, J.G., Failure modes of FRP-strengthened restructures, 26th Conference on Our World in Concrete & Structures: 27-28 August, Singapore (2001) 627-634. [2] SP 164.1325800.2014. Strengthening of reinforced concrete structures with composite materials. design rules (2014) (in Russian). [3] ACI 440.2R-08. Guide for the design and construction of externally bonded FRP systems for strengthening concrete structures. ACI (2008). [4] Zhang, A., Jin, W., Li, G., Behavior of preloaded RC beams strengthened with CFRP laminates, Journal of Zhejiang University SCIENCE A, 7 (2006) 436-444.

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