DAfStb guideline - Strengthening of Concrete Structures with Adhesively Bonded Reinforcement - page 6

Table 2.1 Partial safety factors for adhesively bonded reinforcement for the ultimate limit state.

Design
situation

CFRP
strips

CF
sheets

Bond of
externally
bonded
reinforcement

Bond of near-
surface-
mounted
reinforcement

Bond of steel on
steel or CFRP on
CFRP

Designation

γ LL γ LG γ BA γ BE γ BG

Persistent and
transient

1.2 1.35 1.5 1.3 1.3

Accidental 1.05 1.1 1.2 1.05 1.05

A bond failure with externally bonded reinforcement (steel plates, CFRP strips, CF
sheets) entails a failure in the layer of concrete near the surface. For this reason, when it
comes to the bond of externally bonded reinforcement, the DAfStb guideline uses the
partial safety factors for concrete failure according to [20], as in the earlier approv-
als [28]. According to [30], using such a global partial safety factor for the bond of
externally bonded reinforcement - instead of individual partial safety factors for every

variable in the design equations resulted in the smallest deviations in the level of safety

when comparing various sample calculations.

-

2.6 Applications

2.6.1 Member to be strengthened
The DAfStb guideline can be applied to concrete members complying with DIN EN
1992-1-1 [20, 21]. The design approaches of the guideline were prepared based on the
theories of mechanics and calibrated and validated by means of tests on normal-weight
concretes of strength classes C12/15 to C50/60. Therefore, the design approaches of the
guideline should not be applied to other construction materials without carrying out
additional investigations. In order to keep within the range of experience of the
experimental studies available, the guideline speci es the following exceptions:
- The DAfStb guideline cannot be used for strengthening lightweight concrete.
- The DAfStb guideline only covers the strengthening of normal-weight concretes of
strength classes C12/15 to C50/60.
Furthermore, the guideline [1, 2] cannot be applied to components made from steel fibre-
reinforced concrete or autoclaved aerated concrete. So extending DIN EN 1992-1-1 [20]
by means of the DAfStb guideline on steel fibre-reinforced concrete [31] and combining
this with the DAfStb guideline on the strengthening of concrete members with
externally bonded reinforcement [1, 2] is not permitted.
The DAfStb guideline on the strengthening of concrete members with adhesively bonded
reinforcement [1, 2] can only be used to design strengthening for concrete components.
It cannot be used to design strengthening measures for masonry components (see [32], for