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The stiffness coefficients and their usage in the steel connections are defined by the EN 1993-1-8 Article 6.3.1 Table 6.9 and 6.10.:
|
Coefficient |
Basic component |
Formula |
|---|---|---|
|
k1 |
column web panel in shear |
|
|
2 |
column web in compression |
|
|
k3 |
column web in tension, single bolt row in tension |
|
|
k4 |
column flange, single bolt row in tension |
|
|
k5 |
endplate, single bolt row in tension |
|
|
K10 |
bolts, single bolt row in tension |
|
with
|
Avc |
the shear area of the column |
|
z |
the lever arm |
|
b |
the transformation parameter |
|
beff |
the effective width of the column web |
|
dc |
the clear depth of the column web |
|
leff |
the smallest effective length for the bolt (minimum of individual and relevant partial effective lengths) |
|
m |
|
|
As |
the tensile stress area of the bolt |
|
Lb
|
the elongation length of the bolt |
In SCIA Engineer the usage of the stiffness coefficients is related to a connection type:
For a bolted beam-to-column connection, the following coefficients are used :
|
Coefficient |
Present |
keq |
|---|---|---|
|
k1 |
x |
|
|
k2 |
x |
|
|
k3 |
x |
x |
|
k4 |
x |
x |
|
k5 |
x |
x |
|
K10 |
x |
x |
For a welded beam-to-column connection, the following coefficients are used :
|
Coefficient |
Present |
keq |
|---|---|---|
|
k1 |
x |
|
|
k2 |
x |
|
|
k3 |
|
|
|
k4 |
x |
|
|
k5 |
|
|
|
K10 |
|
|
When a column minor axis configuration is used, the values for k1 and k2 are replaced by ki, the stiffness coefficient in the tension or the compression zone of the column web in bending and punching. The value for ki is given by (see Ref.[21]) :
with
|
c1 |
1.50 |
|
c2 |
1.63 |
|
|
10≤u≤50 |
|
|
0.08≤β≤0.75 |
|
|
0.05≤α≤0.2 |
|
|
|
The factor krot is equal to 1 if the rotation of the column flanges restrained
For a bolted plate-to-plate connection, the following coefficients are used :
|
Coefficient |
Present |
keq |
|---|---|---|
|
k1 |
|
|
|
k2 |
|
|
|
k3 |
|
|
|
k4 |
|
|
|
k5 Left side k5 Right side |
x x |
x x |
|
K10 |
x |
x |
A welded plate-to-plate connection is considered as rigid.
For a column base, the following coefficients are used :
|
Coefficient |
Present |
keq |
|---|---|---|
|
k1 |
|
|
|
k2 |
|
|
|
k3 |
|
|
|
k4 |
|
|
|
k5 |
x |
x |
|
K10 |
x |
x |
|
kc |
x |
|
The value of Lb in coefficient k7 is taken as the free length of the anchor bolts plus the free length of embedded part. The free length of the anchor bolts is equal to the base plate thickness plus the head height of the anchor bolt. The free length of the embedded part is equal to 8-times the anchor diameter.
The stiffness kc is the stiffness coefficient for the compression zone in the concrete block.
with
|
Afl |
the bearing area under the compression flange |
|
Ec |
the E modulus of concrete
(Ec in Gpa, fck in Mpa) |
|
E |
the Young modulus (of steel) |
|
heq |
the equivalent height
where aeff and beff are based on the rectangle for determining Afl Afl=aeff x beff |
