Example 3: Column strengthening - Strengthening of Concrete Structures with Adhesively Bonded Reinforcement - page 125

The factor to allow for the geometry of the compression member and the strain in
the confining reinforcement is determined according to DAfStb guideline [1, 2] part 1
Eq. (RV 6.98):

l 0
D

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

3000
500 1 : 08 ) 1 : 0

ξ 2 1 : 15 0 : 06 ? 0 : 932 0 : 01 0 : 012 ? 0 : 932 ?

The strain coef cient ρ ε according to DAfStb guideline [1, 2] part 1 Eq. (RV 6.99) is
used here.
ρ ε ε juk

1 : 863

2 : 0

ε c2

0 : 932

The maximum curvature of the con ned cross-section is determined according to
DAfStb guideline [1, 2] part 1 Eq. (RV 6.100):

ε cu ε yk

ϕ bal 2 ?

D D c 2 ? ϕ w ϕ s

0 : 00479 0 : 0025

63 ? 10 5

ϕ bal 2 ? 1 :

500 439 : 5 2 ? 10 25

In the above equation the ultimate strain of the confined concrete ε cu and the strain
in the longitudinal reinforcing steel upon reaching the characteristic yield strength
ε yk are required according to DAfStb guideline [1, 2] part 1 Eqs. (RV 6.101) and
(RV 6.102):

863 ? 10 3
38

E jl ? ε juk
f cm

690 ? 1 :

ε cu ε c2 ? 1 : 75 19 ? 2 : 0 ? 1 : 75 19 ?

4 : 79 mm = m

f syk
E s

500
200 000

ε yk 2 : 5mm = m

The factor K φ takes into account the increase in the curvature due to the
creep processes over time and is calculated according to DIN EN 1992-1-1 [20]
Eq. (RV 5.37):
K φ

1 β ? φ ef 1

K φ 1 0 : 34 ? 0 : 45 1 : 15

The coefficient β to DIN EN 1992-1-1 [20] section 5.8.8.3 (4) and the effective creep

coef cient φ ef to DAfStb guideline [1, 2] part 1 Eq. (RV 6.103) are used here.