Design of strengthening measures with externally bonded CFRP strips - Strengthening of Concrete Structures with Adhesively Bonded Reinforcement - page 33

Fig. 3.11 Geometric situation (schematic) for U-wrapping

smaller and smaller. This is taken into account by Equations 3.81 to 3.83 because as the
distance between the links decreases, so the effect of an individual link is reduced further
and further.
When d l bL ; max and l bL ; max s Lw d , then

f bLk ; max
γ BA

f bLwd (3.81)

When d l bL ; max and s Lw l bL ; max , then

f bLk ; max
γ BA

m Lw 1 m Lw ? m Lw 1 ? s Lw

f bLwd 1 (3.82) ?

n Lw 1 2 ? n Lw 1 ? l bL ; max

When d l bL ; max and s Lw d , then

f bLk ; max
γ BA

n Lw ? s Lw
2 ? l bL ; max

f bLwd (3.83) ?

The bond strength f bLk,max and the effective bond length l bL,max in the equations are
determined as shown in Section 3.3.4.3.

3.4.3 End strap to prevent concrete cover separation failure
When using externally bonded or near-surface-mounted reinforcement, the layer of
concrete directly beneath the reinforcement can become detached near the supports.