Issue 38

I. N. Shardakov et alii, Frattura ed Integrità Strutturale, 38 (2016) 331-338; DOI: 10.3221/IGF-ESIS.38.43 337 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. Specimen Binary card of defects The relative area of the delamination, % CFRP strain, με particular value Average value B1b-3 7.8 9.71 10300 B1b-4 12.99 10660 B1b-5 8.34 10140 B1c-1 19.77 22.93 10280 B1c-2 22.59 8020 B1c-3 26.43 10240 B2b-3 11.78 14.90 10810 B2b-4 20.18 10200 B2b-5 12.73 10070 B2c-1 17.86 32.41 8970 B2c-2 33.08 7220 B2c-3 46.29 10450 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.