CEMPE
TI 80907
30 November 1998
I
r=
(Eq C40)
A
The effective area, Ae is calculated as follows for columns builtup from coldformed steel studs such that
they form a closed section or structural tube columns (AISI, C4):
A e = A c  nt c ( w  b)
(Eq C41)
Where:
Ac = the nominal column area.
n = the number of studs making up the column, or is 2 when using structural tube columns.
tc= the thickness of the stud material used in the builtup columns, or the thickness of the
structural tube column.
w = the flat width of the stud web making up the builtup columns, or the width of the structural
tube face perpendicular to the plane of the panel. Assuming the outside radius of the stud
corners is twice the thickness, tc this may be calculated as follows:
w = ds  4tc
(Eq C42)
ds = the depth of the studs making up the builtup columns, or the structural tube width
perpendicular to the plane of the panel,
b = the effective width and shall be determined as follows (AISI, B2.2):
dh
w
0.5 ≥
≥ 0, and ≤70
for
and
w
tc
the distance between centers of holes ≥ 0.5w and ≥ 3dh,
when λ≤ 0.673
b = w dh
(Eq C43)
0.22 0.8dh
w 

1
w
λ
when λ> 0.673
b=
(Eq C44)
λ
Where:
dh = the diameter of holes.
λ= a slenderness factor defined as follows (AISI, B2.1):
1.052 w Fn
λ=
(Eq C45)
k t c E
Where:
k = the plate buckling coefficient, equal to 4 for the studs making up the builtup columns or
structural tube columns.
C14. COLUMN SHEAR CAPACITY. The column shear design strength, Vc shall be determined as
follows for columns builtup with coldformed steel studs or individual structural tubing members (AISI,
C3.2, Strength for Shear Only):
C11