Civil Engineering Reference
In-Depth Information
Circular Columns
1
2
Duetothe arch actioninbetween hoops andspirals
f
=ρ
f
l
s yt
1
2
4
f
k
f
=ρ
l
e
syt
A
dS
sp
ρ=
s
c
For circular hoops
2
s
d
1
−
2
c
k
=
e
1
−ρ
cc
For circular spirals
s
d
1
−
2
c
cc
k
=
e
1
−ρ
where
s
′
=
clear spacing of hoops or clear pitch of spiral
d
c
=
diameter of concrete core c/c
ρ
cc
=
ratio of longitudinal reinforcement area to the area of core
7.94
f
f
f
l
l
c
f
=− +
f
1.254
2.254 1
+
−
2
Mander
et al
.(1988)
cc
c
f
c
ACI 318-11 equationof Section 10.9.3:
AA
A
−
f
f
g
c
c
yt
ρ=
0.45
s
c
ρ
fA
=
0.45
fA
sytc
c
cover
2
fA
=
0.45
fA
l
c
c
cover
f
=+
f
4.1
f
Richart
etal
.(1928)
cc
c
l
f
−
f
cc
c
f
=
l
4.1
(
)
0.488
f
−
f
A
=
0.45
f A
cc
c
c
c
cover
(
)
0.57
×
0.85
f
−
f
A
=
0.53
×
0.85
f A
cc
c
c
c
cover
(
)
0.85
f
f
A
0.92
0.85
f A
−
=
×
cc
c
c
c
cover
The two terms on both sides of this equation are almost equal.
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