Issue 38

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

Rebound deflection, mm

Specimen failure behavior RR+CCC RR*+CCC RR*

M crc , kNm

M ult , kNm

f ult , mm 9.50

a crc,max mm

ε f,ult με

,

,

Debonding type

Specimen Concrete class

Bla-1 Bla-2 Bla-3 B1b-1 Blb-2 Blb-3 Blb-4 Blb-5 B2a-1 B2a-2 B2a-3 B2b-1 B2b-2 B2b-3 B2b-4 B2b-5

B25 B25 B25 B25 B25 B20 B30 B20 B35 B35 B40 B35 B40 B40 B40 B40 - -

3.81 3.91 4.27 4.00 4.28 5.07 4.33 5.40 4.32 4.74 5.15 4.98 4.96 6.14 5.79 5.49 5.09 5.43 4.68

0.183

6.13 7.45 6.92 6.83

2.7 2.0 2.0 2.2 1.1 0.5 1.0 0.9 1.1 1.5 7.0 3.0 2.2 0.8 1.6 1.1 1.0 1.3 0.9

- - - -

- - - -

-

19.84 21.43 14.29 11.16 8.30 8.08 9.78 12.72 - 10.60 15.75 19.73 10.37 12.52 8.92 9.31 8.06 11.44 - 8.72

Mean value

0.183

-

- -

10.05 10.42 10.25 10.10 11.07 10.24

12170 11170 13370 12180 15040 11670

mixture mixture cohesion

FRPR* FRPR* FRPR

0.206 0.257 0.218

cohesion. FRPR cohesion. FRPR

Mean (adhesive) Mean (cohesive)

-

-

0.227

10.47

13530

-

- -

6.98 6.98 7.39 7.12

- - - -

RR*

RR+CCC RR*+CCC

0.221 0.221

Mean value

-

- -

10.03 10.19 10.56 11.46 10.27 10.11

12180 10860 13790 14280 12190 11520

mixture.

FRPR*

adhesion FRPR* cohesion. FRPR cohesion. FRPR cohesion. FRPR

0.260 0.213 0.252

Mean (adhesive) Mean (cohesive)

-

-

-

-

5.59

1.1

- - Notes: RR reinforcement rupture, CCC - crushing of compressive concrete, RR* - reinforcement rupture sectional weakened spot welding, FRPR - midspan FRP rupture, FRPR* - FRP rupture sectional strap anchorage, mix. - mixed debonding, coh. - cohesive debonding, adh. - adhesive debonding Table 1 : The results of static test of beams of series A and B. 0.242 10.76 8.76 13420 -

Loading before the appearance of the first cracks

Bending moment during reinforce

Loading after the appearance of the first cracks and their grouting

Con crete class

Specimen failure behavior

Speci men

Maximum bending moment, kNm

Debond ing type

Rebound deflection, mm

M crc , kNm

a crc,max mm

M crc , kNm

M ult , mm f ult

, mm a crc,max , mm

ε f,ult με

,

,

ment, kNm 4.30 4.81 4.59

Blc-1 B20 3.32 Blc-2 B20 3.60 Blc-3 B30 3.86

0.142 0.164 0.186

5.15 5.23 5.20 5.19 5.49 5.64 5.52 5.55

1.0 1.5 1.0 1.2 1.0 0.9 1.0 1.0

6.79 10.39 10.80 1.4 11680 cohes.

FRPR FRPR FRPR

7.19 8.75 9.19

1.5 10190 cohes.

6.59 10.19 11.07 1.3 12760 cohes.

Mean value

-

3.60

-

4.57 4.56 4.79 4.58 4.64

6.86 10.29

-

1.4 11540

-

-

B2c-1 B40 4.30 B2c-2 B40 4.92 B2c-3 B40 5.19

0.179 0.214 0.202

6.88 1137 10.29 1.1 14180 cohes.

FRPR

7.02 9.03 9.75

1

8655 cohes. RR*+ FRPR

7.69 10.62 10.72 1.3 12430 cohes.

FRPR

Mean value

-

4.80

-

7.19 11.00

-

1.1 13305

-

-

Table 2 : The results of static tests of beams of series C. The evolution of deformation in the beams reinforced under the load is of particular interest. At the initial stage of loading such a beam behaves in the same way as a non- strengthened one (Fig. 4, solid thick lines). The

335