Civil Engineering Reference
In-Depth Information
γ
R,t
is the partial resistance factor for axial tensile
strength, in stress units; and
γ
R,t
= 1.05.
The member unity check U
c
under axial tension is calculated from:
strength,
f
t
F
t
γ
R,t
U
c
=
(3.26)
Axial Compression
Tubular members subjected to axial compressive forces should be designed to
satisfy the following condition:
F
c
γ
R,c
f
c
≤
(3.27)
where f
c
is the axial compressive stress due to forces from factored actions; F
c
is
the representative axial compressive strength, in stress units; and
γ
R,c
is the par-
tial resistance factor for axial compressive strength,
γ
R,c
= 1.18.
The member unity check U
c
under axial compression should be calculated
from
Equation (3.28)
:
f
c
F
c
γ
R,c
U
c
=
(3.28)
Column Buckling
In the absence of hydrostatic pressure, the representative axial compressive
strength for tubular members should be the smaller of the in-plane and the
out-of-plane buckling strengths determined from the following equations:
2
F
c
= ½
1
:
0
−
0
:
278
λ
F
yc
for
λ ≤
1
:
34
(3.29)
0
:
9
F
c
=
2
F
yc
for
λ >
1
:
34
(3.30)
λ
where
r
F
yc
E
r
F
yc
F
e
KL
π
λ =
=
(3.31)
r
where F
c
is the representative axial compressive strength, in stress units; F
yc
is
the representative local buckling strength, in stress units;
is the column slen-
derness parameter; F
e
is the smaller of the Euler buckling strengths in the y- and
z-direction, in stress units; E is Young
λ
s modulus of elasticity; K is the effective
length factor; L is the unbraced length in the y-orz-direction; r is the radius of
gyration r
'
q
; I is the moment of inertia of the cross-section; and A is the
cross-sectional area.
=
Search WWH ::
Custom Search