nzs 3404-1997 example 001
DESCRIPTION
nzsTRANSCRIPT
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PROGRAM NAME: ETABS 2013
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NZS 3404-1997 Example 001 - 1
NZS 3404-1997 Example 001
WIDE FLANGE MEMBER UNDER COMPRESSION
EXAMPLE DESCRIPTION
The frame object axial strengths are tested in this example.
A continuous column is subjected to factored load N = 200 kN. This example
was tested using the NZS 3404-1997 steel frame design code. The design
capacities are compared with independent hand calculated results.
GEOMETRY, PROPERTIES AND LOADING
L = 6 m
TECHNICAL FEATURES TESTED
Section compactness check (compression)
Section compression capacity
Member compression capacity
Material Properties
E = 200x103 MPa
v = 0.3 G = 76923.08 MPa
Loading
N = 200 kN
Design Properties
fy = 250 MPa
Section: 350WC197
N
L
A A
Section A-A
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PROGRAM NAME: ETABS 2013
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NZS 3404-1997 Example 001 - 2
RESULTS COMPARISON
Independent results are taken from hand calculations based on the CSI steel
design documentation contained in the file “SFD-NZS-3404-1997.pdf,” which is
available through the program “Help” menu.
Output Parameter ETABS Independent
Percent Difference
Compactness Compact Compact 0.00%
Section Axial Capacity, Ns (kN) 6275 6275 0.00%
Member Axial Capacity, Nc (kN) 4385 4385 0.00%
COMPUTER FILE: NZS 3404-1997 EX001
CONCLUSION
The results show an exact comparison with the independent results.
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PROGRAM NAME: ETABS 2013
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NZS 3404-1997 Example 001 - 3
HAND CALCULATION
Properties:
Material:
fy = 250 MPa
Section: 350WC197
Ag = An = 25100 mm2
bf = 350 mm, tf = 28 mm, h = 331 mm, tw = 20 mm
r33 = 139.15 mm, r22 = 89.264 mm
Member:
le33 = le22 = 6000 mm (unbraced length)
Considered to be a braced frame
Loadings:
* 200 kNN
Section Compactness:
Localized Buckling for Flange:
( ) 350 20 2505.89
2 250 2 28 250
f w y
e
f
b t f
t
Flange is under uniform compression, so:
9, 16, 90ep ey ew
5.89 9e ep
, No localized flange buckling
Flange is compact
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PROGRAM NAME: ETABS 2013
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NZS 3404-1997 Example 001 - 4
Localized Buckling for Web:
331 25016.55
250 20 250
y
e
w
fh
t
Web is under uniform compression, so:
30, 45, 180ep ey ew
16.55 30e ep
, No localized web buckling
Web is compact.
Section is Compact.
Section Compression Capacity:
Section is not Slender, so Kf = 1.0
31 25,100 250 / 10
s f n yN K A f
6275kNs
N
Member Weak-Axis Compression Capacity:
Frame is considered a braced frame in both directions, so 22 33
1e e
k k
22 33
22 33
6000 600067.216 and 43.119
89.264 139.15
e el l
r r
Buckling will occur on the 22-axis.
22
22
22
1 250600067.216
250 89.264 250
f ye
n
K fl
r
22
22 2
22 22
2100( 13.5)20.363
15.3 2050
n
a
n n
220.5
b since cross-section is not a UB or UC section
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PROGRAM NAME: ETABS 2013
REVISION NO.: 0
NZS 3404-1997 Example 001 - 5
22 22 22 2267.216 20.363 0.5 77.398
n a b
22 220.00326( 13.5) 0.2083 0
2 2
22
22
22 2 2
22
77.3981 1 0.2083
90 901.317
77.39822
9090
2
22 22
22 22
901 1
c
2
22
901.317 1 1 0.6988
1.317 77.398c
22 22c c s sN N N
220.6988 6275 4385 kN
cN