DESIGN STRENGTH OF COLUMNS
3 - 73
Fy = 36 ksi Fy = 50 ksi
Y
COLUMNS Double angles
X
X
Design axial strength in kips (φ = 0.85)
Unequal legs
3/ ′′ 8
Long legs 3⁄8 in. back to back of angles 3⁄ 8
Thickness Wt./ft
10.6
X-X AXIS
Fy
Y-Y AXIS
5⁄ 16
1⁄ 4
9.0
3⁄ 16
7.2
5.5
36
50
36
50
36
50
36
50
0
95
131
80
111
65
91
49
63
2 3 4 5 6
90 84 77 69 60
122 112 99 84 69
76 72 66 59 51
104 95 84 72 59
62 58 54 48 42
85 78 69 59 49
46 44 40 36 32
59 55 49 43 36
7 8 9 10 11
50 42 33 27 22
55 42 33 27 22
43 36 29 23 19
47 37 29 23 19
36 30 24 19 16
39 30 24 19 16
27 23 19 15 12
30 24 19 15 12
12 13
19
19
16
16
13 11
13 11
10 9
10 9
0
95
131
80
111
65
91
49
63
2 3 4 5 6
89 85 80 74 67
120 113 104 93 82
74 71 66 61 55
99 93 85 76 66
58 56 52 48 44
77 73 67 60 52
41 39 37 34 31
50 48 44 40 36
7 8 9 10 11
60 52 45 38 32
70 58 47 38 32
49 42 36 32 26
56 48 39 32 26
39 33 28 25 21
44 36 31 25 21
28 24 21 17 15
31 26 22 18 15
12 13 14 15 16
27 23 20 17 15
27 23 20 17 15
22 19 16 14
22 19 16 14
17 15 13 11
17 15 13 11
13 11 10 8
13 11 10 8
b
Properties of 2 angles—3⁄8 in. back to back 2
A (in ) rx (in.) ry (in.)
No. of a Connectors
21⁄2×2
Size
Effective length KL (ft) with respect to indicated axis
Y
3.09 0.768 0.961
2.62 0.776 0.948
2.13 0.784 0.935
aFor Y-Y axis, welded or fully tensioned bolted connectors only. bFor number of connectors, see double angle column discussion.
AMERICAN INSTITUTE OF STEEL CONSTRUCTION
1.62 0.793 0.923
2
3