Civil Engineering Reference
In-Depth Information
143 in.
3
S
x
=
r
x
=
6.14 in.
362 in.
4
I
y
=
49.9 in.
3
S
y
=
r
y
=
3.70 in.
L
r
min
=
(
19.55
)(
12
)
3.70
=
63.4
≤
100 Ok
5.034
E
KL
r
min
=
0.75
(
19.55
)(
12
)
3.70
=
47.6
≤
F
y
≤
121
0.629
E
KL
r
min
=
47.6
≥
F
y
≥
15
17,500
F
y
E
3
/
2
KL
r
min
0.166
KL
r
min
F
all
=
0.60
F
y
−
=
30
−
=
30
−
7.9
=
22.1 ksi
P
all
=
F
all
(A)
=
22.1
(
26.5
)
=
586
≥
550 ksi OK.
Design of the laced section
Compression member: 2
50 channels laced 6
2
in. back to back
−
C
15
×
with 4 in.
×
(
1
/
2
)
in. lacing bars as shown in Figure E6.5.
For C15
×
50 channel:
14.7 in.
2
A
=
6-1/2"
15"
1-1/2"
11"
11"
14"
FIGURE E6.5
