Civil Engineering Reference
In-Depth Information
140 respectively, according to EN 199319. Checking and documentation of the cutting qual-
ity is very important as inspection of the shear connector is not possible after casting. To
prevent blowholes in the concrete next to the composite dowel, the maximum grain size is
limited to 16 mm and the consistence of the fresh concrete should be soft to flowable.
7. Outlook
The general technical approval is a consistent continuation of the development of standard-
ization of composite dowels: it started with approvals for single cases and should become
a German steel guideline (DASt) in the future. For this, the presented design concept is a
strong basis. Due to the given regulations uncertainties in design of composite dowels are
eliminated. This enables an economic and timesaving application of these powerful shear
connectors. Additional costs for approvals for single cases are omitted. For the future, it is
planned to implement composite dowels in Eurocode 4 as alternative shear connector besides
headed studs.
8. Notations
P
sh,k
[N]
Characteristic value of the concrete shearing resistance
P
po,k
[N]
Characteristic value of the concrete pry-out resistance
P
pl,k
[N]
Characteristic value of the steel resistance
e
x
[mm]
Distance of recesses in longitudinal direction
h
D
[-]
Reduction factor depend on the dowel geometry
h
D
[-]
Reinforcement ratio for transversal reinforcement
h
D,i
[-]
Effective reinforcement ratio for transversal reinforcement
E
S
[N/mm²]
Young's modulus of reinforcing steel
E
cm
[N/mm²]
Secant modulus of elasticity of concrete
A
b
[mm²]
Lower reinforcement in the range of A
D
A
t
[mm²]
Upper reinforcement in the range of e
x
A
D
[mm²]
Concrete dowel area
A
D,i
[mm²]
Effective concrete area (ex ∙ hc)
A
sf
[mm²]
Effective reinforcement (A
b
+ A
t
)
c
o
[mm]
Thickness of upper concrete cover
c
u
[mm]
Thickness of lower concrete cover
h
po
[mm]
Pry out cone height
f
ck
[N/mm²]
Characteristic value of the cylinder compressive strength of concrete
f
y
[N/mm²]
Nominal value of the yield strength of structural steel
χ
x
[-]
Reduction factor for concrete pry out in longitudinal direction
χ
y
[-]
Reduction factor for concrete pry out in transversal direction
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