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AISC ASD-89 Example 002 WIDE FLANGE MEMBER UNDER COMPRESSION EXAMPLE DESCRIPTION The column design features for the AISC ASD-89 code are checked for the frame shown below. This frame is presented in the Allowable the Allowable Stress Design Manual of Steel Construction, Construction, Ninth Edition, 1989, Example 3, Pages 3-6 and 3-7. The column K column K factors factors were overwritten to a value of 2.13 to match the example. The transverse direction was assumed to be continuously supported. Two point loads of 560 kips are applied at the tops of each column. The ratio of allow axial stress, F a, to the actual, f actual, f a, was checked and compared to the referenced design code.
GEOMETRY, PROPERTIES AND LOADING
TECHNICAL FEATURES TESTED
Section compactness check (compressi (co mpression) on) Member compression capacity
AISC ASD-89 Example Example 002 - 1
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RESULTS COMPARISON Independent results are taken from Allowable Stress Design Manual of Steel Construction, Ninth Edition, 1989, Example 3, Pages 3-6 and 3-7.
Output Parameter Compactness Design Axial Stress, f a (ksi) Allowable Axial Stress,
ETABS
Independent
Percent Difference
Compact
Compact
0.00%
15.86
15.86
0.00%
16.47
16.47
0.00%
F a (ksi)
COMPUTER FILE: AISC ASD-89 EX002 CONCLUSION The results show an exact comparison with the independent results.
AISC ASD-89 Example 002 - 2
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HAND CALCULATION Properties:
Material: A36 Steel E = 29,000 ksi, F y = 36 ksi Section: W12x120: b f = 12.32 in, t f = 1.105 in, d =13.12 in , t w=0.71 in A = 35.3 in2 r x=5.5056 in Member: K = 2.13 L = 15 ft Loadings:
P = 560 kips Design Axial Stress: P
f a
f a
560
A
35.3
15.86 ksi
Compactness:
Localized Buckling for Flange:
b f
12.32
2 t f
2
65
p
5.575
1 .1 0 5 65
F y p
10.83
36
, No localized flange buckling
Flange is Compact.
AISC ASD-89 Example 002 - 3
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Localized Buckling for Web: f a
15.86
36
d
13.12
Since
0.71
f a
0 .4 4
257
p
42.83
36
F y
0 .1 6
F y 257
18.48
t w
p
0.44
F y
, No localized web buckling
Web is Compact. Section is Compact.
M ember Compr ession Capacity KL x
2 . 13
12
69 . 638
5 . 5056
r x
2
C c
15
2
E
2
2
29000
F y
126.099
36
KL x r x
69 . 638
KL x r x
0 . 552
126 . 099
C c
C c
AISC ASD-89 Example 002 - 4
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1 . 0
F a 5 3
F a
5 3
F a
KL x r x F y C 2 c 2
1
KL x r x 8 C c 3
1 . 0
3 8
1 2
ETABS 2013 0
2
KL x r x C 8 c
3
1
0 . 552 36
0 . 552
1 8
0 . 552
3
16.47 ksi
AISC ASD-89 Example 002 - 5
