V. ASME NF 3000 1998 Channel
Verify the design of channel section used for a beam member using the ASME NF 3000 1998 code.
Details
The beam is a propped cantilever 80 inches long. The beam is loaded with a 2 kip concentrated load at midspan and a uniformly distributed load of 1 kip/in over the entire length.
The member is C15x50 channel section with Grade A36 steel.
Validation
Maximum shear force (at fixed end): V = 51.375 kips (taken from STAAD.Pro analysis)
Maximum moment (at fixed end): M = 830.0 in-kip (taken from STAAD.Pro analysis)
Slenderness Ratio
About z-axis: (KL/r)z = 0.85(80 in)/(5.25 in) = 12.95
About y-axis: (KL/r)y = 0.85(80 in)/(0.865 in) = 78.61
Max. slenderness ratio < 300, OK.
Bending About Major Axis (Z Axis)
The laterally unsupported length of the compression flange,
and
As bf/tf is not in the range of 65/√(Fy) and 95/√(Fy) , the value of allowable bending compressive and tensile stress = Fbty = Fbcy = 0.6×Fy = 21.6 ksi
Actual bending stress:
Bending Tensile Stress = bending compressive stress = fbtz = fbcz= MzD / (2Iz) = 15.4 ksi
Critical ratio = 15.41 ksi / 21.6 ksi = 0.713
Shear
Actual shear:
Allowable shear:
a = clear distance between transverse stiffeners (here taken as length) = 80 in
h = clear distance flanges of the girder = D-2tf = 14.35 in
Thus, a/h = 5.57, Therefore, k = 5.34 + [4.00/ (a/h)2] = 5.46
Hence allowable=14.4 ksi
Therefore, Ratio = fv/Fv = 0.330
Results
Parameter | Hand Calculation | STAAD.Pro | Difference | Comments |
---|---|---|---|---|
Slenderness ratio | 78.61 | 78.61 | none | |
Allowable bending stress (ksi) | 21.6 | 21.6 | none | |
Actual bending stress (ksi) | 15.4 | 15.4 | none | |
Critical ratio | 0.713 | 0.713 | none | |
Allowable shear stress (ksi) | 14.4 | 14.4 | none | |
Actual shear stress (ksi) | 4.76 | 4.78 | 0.4% |
STAAD Input
The file C:\Users\Public\Public Documents\STAAD.Pro 2024\Samples \Verification Models\09 Steel Design\US\ASME\ASME NF 3000 1998 Channel.std is typically installed with the program.
STAAD SPACE
START JOB INFORMATION
ENGINEER DATE 10-Aug-18
END JOB INFORMATION
SET SHEAR
INPUT WIDTH 79
UNIT INCHES POUND
JOINT COORDINATES
1 0 0 0; 2 80 0 0;
MEMBER INCIDENCES
1 1 2;
DEFINE MATERIAL START
ISOTROPIC STEEL
E 2.9e+007
POISSON 0.3
DENSITY 0.283
ALPHA 1.2e-005
DAMP 0.03
TYPE STEEL
STRENGTH FY 36000 FU 58000 RY 1.5 RT 1.2
END DEFINE MATERIAL
MEMBER PROPERTY AMERICAN
1 TABLE ST C15X50
CONSTANTS
MATERIAL STEEL ALL
SUPPORTS
1 FIXED
2 PINNED
LOAD 1 LOADTYPE None TITLE LOAD CASE 1
MEMBER LOAD
1 CON GY -2000 40
1 UNI GY -1000 0 80
PERFORM ANALYSIS
PARAMETER 1
CODE NF3000 1998
CMY 1 ALL
CMZ 1 ALL
FU 58000 ALL
FYLD 36000 ALL
KY 0.85 ALL
KZ 0.85 ALL
UNT 80 ALL
UNB 80 ALL
MAIN 200 ALL
NSF 0.9 ALL
RATIO 1 ALL
TMAIN 300 ALL
TRACK 2 ALL
CHECK CODE ALL
PARAMETER 2
CODE NF3000 2004
CAN 0 ALL
CB 1 ALL
CMY 0.6 ALL
CMZ 0.6 ALL
CT 0.8 ALL
DFF 0 ALL
DJ1 1 ALL
DJ2 2 ALL
DMAX 39370.1 ALL
DMIN 0 ALL
FU 60000.4 ALL
FYLD 36000.2 ALL
KY 1 ALL
KZ 1 ALL
LY 0 ALL
LZ 0 ALL
MAIN 200 ALL
NSF 0.7 ALL
PROFILE W14 ALL
RATIO 1 ALL
STIFF 5 ALL
STYPE 0 ALL
TMAIN 301 ALL
TRACK 2 ALL
UNB 0 ALL
UNT 0 ALL
PRINT ANALYSIS RESULTS
FINISH
STAAD Output
STAAD.PRO CODE CHECKING - ( ASME NF3000-98) v2.0
********************************************
ALL UNITS ARE - POUN INCH (UNLESS OTHERWISE Noted)
MEMBER TABLE RESULT/ CRITICAL COND/ RATIO/ LOADING/
FX MY MZ LOCATION
=======================================================================
1 ST C15X50 (AISC SECTIONS)
PASS NF-98-EQN-22 0.713 1
0.00 T 0.00 829999.94 0.00
|-----------------------------------------------------------------------------|
| SLENDERNESS CHECK: ACTUAL RATIO: 78.61 ALLOWABLE RATIO: 300.00 |
| ALLOWABLE STRESSES: (UNIT - POUN INCH) |
| AXIAL: 1.55E+04 FCZ: 2.16E+04 FCY: 2.16E+04 FTZ: 2.16E+04 FTY: 2.16E+04 |
| SHEAR: 1.44E+04 |
| ACTUAL STRESSES: (UNIT - POUN INCH) |
| AXIAL: 0.00E+00 FBZ: 1.54E+04 FBY: 0.00E+00 SHEAR: 4.78E+03 |
|-----------------------------------------------------------------------------|
| SECTION PROPERTIES: (UNIT - INCH) |
| AXX: 14.70 AYY: 10.74 AZZ: 3.22 RZZ: 5.24 RYY: 0.87 |
| SZZ: 53.87 SYY: 3.77 |
|-----------------------------------------------------------------------------|
| PARAMETER: (UNIT - POUN INCH) |
| KL/R-Z: 12.97 KL/R-Y: 78.61 UNL: 80.0 CMZ: 1.00 CMY: 1.00 |
| CB: 1.00 FYLD: 36000.00 FU: 58000.00 NET SECTION FACTOR: 0.90 |
| CT: 0.75 STEEL TYPE: 0.0 KS:1.000 KV:1.000 KBK:1.000 |
|-----------------------------------------------------------------------------|
| CRITICAL LOADS FOR EACH CLAUSE CHECK (UNITS POUN-INCH) |
| CLAUSE RATIO LOAD FX VY VZ MZ MY |
| TENSION 0.000 0 0.00E+00 - - - - |
| COMPRESSION 0.000 0 0.00E+00 - - - - |
| COMP&BEND 0.713 1 0.00E+00 - - 8.30E+05 0.00E+00 |
| TEN&BEND 0.000 0 0.00E+00 - - 0.00E+00 0.00E+00 |
| SHEAR-Y 0.332 1 - 5.14E+04 - - - |
| SHEAR-Z 0.000 0 - - 0.00E+00 - - |
|-----------------------------------------------------------------------------|