Design of column strengthening with CF sheets - Strengthening of Concrete Structures with Adhesively Bonded Reinforcement - page 101

ξ 2 factor to allow for the geometry of the compression member and the strain in the

confining reinforcement according to Equation 7.23.

f cc
f c

α 1 1 : 17 0 : 2 ? (7.21)

N bal
N u

0 : 8 ? f cc ? A

N u

ξ 1 1

(7.22)

l 0
D 1

ξ 2 1 : 15 0 : 06 ? ρ ε 0 : 01 0 : 012 ? ρ ε ? (7.23)

ρ ε ε ju
ε c2

(7.24)

where:
f c compressive strength of concrete subjected to uniaxial loading
ρ ε strain coef cient.
In order to determine the theoretically admissible axial load N u , the relative angle θ must
be calculated iteratively within the permissible range of answers by equating the two
expressions (7.19) and (7.20) solved for N u .
Figure 7.7 compares the theoretical load-carrying capacity calculated using the modified
expressions (7.19) and (7.20) of Jiang with the results of the experimental studies of
Fitzwilliam and Bisby [136] as well as Ranger and Bisby [137]. In their tests on

Fig. 7.7 Comparison of the modi ed approach of Jiang for member loadbearing capacity with the
results of the experimental studies by Fitzwilliam and Bisby [136] and Ranger and Bisby [137]