V. AISC LRFD - Non Compact Wide Flange 1
To check the adequacy of a non-compact fully braced W shape to carry a uniformly distributed load of 5.5 kips/ft.
Check flange slenderness:
FL = 50 ksi - 10 ksi = 40 ksi
| Mr = FLSx = 40 × 143 = 5,720 in·k | (F1-7) |
Flanges are non-compact. The nominal moment capacity for the limit state of flange local buckling is:
| (A-F1-3) |
| Mp = FyZx = 50 × 157 = 7,850 in·k |
The flange local buckling limit state capacity:
ϕbMn = 0.9×(7,681) = 6,913 in·k
The ultimate moment is:
The capacity ratio is: 7,425 / 6,913 = 1.074
Results
| Result Type | Reference | STAAD.Pro | Difference | Comments |
|---|---|---|---|---|
| Design flexural strength, ϕbMn (in·kips) | 6,913 | 6,910 | negligible | |
| Capacity ratio | 1.074 | 1.074 | none |
STAAD Input
The file C:\Users\Public\Public Documents\STAAD.Pro CONNECT Edition\Samples\ Verification Models\09 Steel Design\US\AISC\AISC LRFD - Non Compact Wide Flange 1.STD is typically installed with the program.
STAAD SPACE BENDING CAPACITY PER AISC LRFD 3RD ED
START JOB INFORMATION
ENGINEER DATE 23-Sep-18
END JOB INFORMATION
*
* TABLE 5-4, PAGE 5-65, AISC LRFD 3RD ED.
* OBJECTIVE : TO CHECK THE ADEQUACY OF A NON-COMPACT W SHAPE.
*
* BEAM IS FULLY BRACED. ACCORDING TO ABOVE REFERENCE,
* CAPACITY OF A 30 FT LONG W14X90 IS 154/30=5.133 KIP/FT
*
UNIT FEET KIP
JOINT COORDINATES
1 0 0 0; 2 30 0 0;
MEMBER INCIDENCES
1 1 2;
MEMBER PROPERTY AMERICAN
1 TABLE ST W14X90
UNIT INCHES KIP
DEFINE MATERIAL START
ISOTROPIC MATERIAL1
E 29000
POISSON 0.3
END DEFINE MATERIAL
UNIT FEET KIP
CONSTANTS
MATERIAL MATERIAL1 ALL
SUPPORTS
1 PINNED
2 FIXED BUT MZ
LOAD 1
MEMBER LOAD
1 UNI GY -5.5
PERFORM ANALYSIS
UNIT INCHES KIP
PARAMETER 1
CODE LRFD
MAIN 1 ALL
* FULLY BRACED CONDITION IS ACHIEVED WITH A UNT OF 1.0 INCH
UNT 1 ALL
FYLD 50 ALL
TRACK 2 ALL
CHECK CODE ALL
FINISH
STAAD Output
STAAD.PRO CODE CHECKING - (LRFD 3RD EDITION) v1.0 ******************************************** |--------------------------------------------------------------------------| | Y PROPERTIES | |************* | IN INCH UNIT | | * |=============================| ===|=== ------------ | |MEMBER 1 * | AISC SECTIONS | | AX=0.2650E+2 | | * | ST W14X90 | | --Z AY=0.6160E+1 | |DESIGN CODE * | | | AZ=0.1373E+2 | | LRFD 2001 * =============================== ===|=== PY=0.7560E+2 | | * PZ=0.1570E+3 | | * |<---LENGTH (FT)= 30.00 --->| RY=0.3696E+1 | |************* RZ=0.6140E+1 | | | | 618.7 (KIP-FEET) | |PARAMETER | L1 L1 L1 CAPACITIES | |IN KIP INCH | IN KIP INCH | |--------------- + L1 L1 -------------| | KL/R-Y= 97.40 | PNC=0.5628E+3| | KL/R-Z= 58.63 + L1 L1 pnc=0.0000E+0| | UNL = 1.00 | PNT=0.1192E+4| | CB = 1.00 + L1 L1 pnt=0.0000E+0| | PHIC = 0.85 | MNZ=0.6910E+4| | PHIB = 0.90 + mnz=0.7425E+4| | FYLD = 50.00 |L0 L0 MNY=0.3280E+4| | NSF = 1.00 +---+---+---+---+---+---+---+---+---+---| mny=0.0000E+0| | DFF = 0.00 -34.4 VN =0.1663E+3| | dff = 0.00 ABSOLUTE MZ ENVELOPE vn =0.0000E+0| | (WITH LOAD NO.) | | | | MAX FORCE/ MOMENT SUMMARY (KIP-FEET) | | ------------------------- | | | | AXIAL SHEAR-Y SHEAR-Z MOMENT-Y MOMENT-Z | | | | VALUE 0.0 82.5 0.0 0.0 618.8 | | LOCATION 0.0 0.0 0.0 0.0 15.0 | | LOADING 0 1 0 0 1 | | | |**************************************************************************| |* *| |* DESIGN SUMMARY (KIP-FEET) *| |* -------------- *| |* *| |* RESULT/ CRITICAL COND/ RATIO/ LOADING/ *| | FX MY MZ LOCATION | | ====================================================== | | FAIL LRFD-H1-1B-C 1.074 1 | | 0.00 C 0.00 -618.75 15.00 | |* *| |**************************************************************************| | | |--------------------------------------------------------------------------|