Civil Engineering Reference
In-Depth Information
If the effects of shear deformation are included (Equations 6.43 and 6.49d),
1
(L/r)
2
A
ab
r
bb
+
1.10
a
2
2
r
2
31.2
a
b
α =
+
+
A
bb
1
1.10
(
56.7
)
2
(
18
)(
11
)
(
6
2
/
12
)
+
2
(
4.14
)
2
(
18
)
2
29.4
2
(
6
)(
0.5
)
31.2
(
18
)
11
=
+
+
=
1.10
P
all
α
675
1.20
=
P
all
=
=
562
≥
550 kips OK.
2
Check design of 6 in.
×
(1/2) in. batten plates at 18 in. center-to-center spacing:
b
40
=
11
50
=
t
bp
≥
0.22 in. OK
Pa
29.3
F
y
(w
bp
)
2
≥
550
(
18
)
29.3
(
50
)(
6
)
2
=
t
bp
≥
0.20 in. OK.
Check design of the main member with 6 in batten plates at 18 in. center-
to-center spacing:
L
p
/r
p
=
(
12
40 OK (length of the main
member element (channel) between closest connections of adjacent batten
plates)
+
3
)/
0.867
=
17.3
≤
L
p
r
p
=
(
12
3
)
0.867
+
2
3
(
56.7
)
≤
=
17.3
≤
37.8 OK
Va
8
=
13.8
(
18
)
8
M
p
=
=
31.1 in.-kips
31.1
3.78
=
f
p
=
8.2 ksi
0.166
KL
r
min
0.166
(
1.0
)
18
0.867
F
all
=
30
−
=
30
−
=
30
−
3.5
=
26.5
≥
8.2 ksi OK.
Designoftheperforatedcoverplatedsection(4in.
×
8in.perforationsat18in.
center to center)
Compressionmember:2
30channels6 in.backtobackconnected
with 1/2 in. thick perforated cover plates as shown in
Figure E6.7.
For
C
12
−
C
12
×
×
3 channel:
8.82 in.
2
=
A
162 in.
4
I
x
=
27.0 in.
3
S
x
=
