Civil Engineering Reference
In-Depth Information
Equation 3.71 is used to calculate the additional shear force that can be carried. The
angle of the strut should be determined according to DIN EN 1992-1-1 [20] together
with its associated National Annex [21].
A
Lw
s
Lw
?
z
?
f
Lwd
?
cot
V
Rd
;
Lw
θ
(3.71)
The area of the shear strengthening is calculated according to Equation 3.72 depending
on the manner of applying the strengthening:
<
2
?
t
Lw
b
Lw
s
Lw
for strips
A
Lw
s
Lw
(3.72)
:
2
?
t
Lw
for full area
The capacity of the shear strengthening
f
wLd
is determined depending on the material
and the type of strengthening using the following equations:
- Full wrapping in steel: Equation 3.73
- Full wrapping in fibre-reinforced material: Equation 3.78
-
U-wrapping in steel: Equation 3.80
-
U-wrapping in fibre-reinforced material: Equation 3.80.
3.4.2.1 Full wrapping in steel
The strength of full wrapping in steel is the minimum of the yield stress and the stress
that can be transferred across any laps:
f
Lwd
;
GS
min
f
yd
;
f
Gud
;
Lw
(3.73)
The stress that can be transferred across laps is calculated using Equations 3.74 to 3.77
depending on the thickness of the L-straps
t
Lw
and their modulus of elasticity
E
Lw
plus
the length of the lap
l
u,LW
. These equations for lap joints from the DAfStb guideline
[1, 2] are based on [86].
f
Guk
;
Lw
γ
BG
f
Gud
;
LW
(3.74)
8
<
l
u
;
Lw
l
u
;
Lw
;
max
l
u
;
Lw
l
u
;
Lw
;
max
f
Guk
;
Lw
;
max
?
2
l
u
;
Lw
<
l
u
;
Lw
;
max
f
Guk
;
Lw
(3.75)
:
f
Guk
;
Lw
;
max
l
u
;
Lw
l
u
;
Lw
;
max
r
E
Lw
t
Lw
f
Guk
;
Lw
;
max
1
:
004
?
(3.76)
p
E
Lw
?
t
Lw
l
u
;
Lw
;
max
0
:
121
?
(3.77)
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