V. AISC LRFD - Select Wide Flange 1
To select the optimum ASTM A992 W-shape with a design flexural strength of 500 kip-ft.
Problem
Beam is bent about its strong axis, and is continuously braced.
| Fy = 50 ksi |
| Length = 30 ft |
| w = 4.44 kip/ft (equiv. of 500 ft·kip design moment) |
Comparison
| Result Type | Theory | STAAD.Pro | Difference |
|---|---|---|---|
| Optimum section | W24x55 | W24x55 | none |
| Design strength, ϕbMz (ft·kips) | 506 | 502.5 (*) | <1% |
* Calculated as MZ envelope value divided by the MZ ratio:
499.95 ft·kips/0.995 = 502.5 ft·kips
STAAD Input
The file C:\Users\Public\Public Documents\STAAD.Pro CONNECT Edition\Samples\ Verification Models\09 Steel Design\US\AISC\AISC LRFD - Select 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 5.2, PAGE 5-40, AISC LRFD 3RD ED.
* OBJECTIVE : TO SELECT THE MOST OPTIMUM SECTION WITH A DESIGN
* FLEXURAL STRENGTH OF 500 KIP-FT.
* FOR A FULLY BRACED BEAM, PER ABOVE REFERENCE, IT SHOULD BE
* A W24X55
*
* 500 KIP-FT IS EQUAL TO AN APPLIED LOAD OF 4.444 KIP/FT ON
* A SIMPLY SUPPORTED BEAM
*
UNIT FEET KIP
JOINT COORDINATES
1 0 0 0; 2 30 0 0;
MEMBER INCIDENCES
1 1 2;
MEMBER PROPERTY AMERICAN
1 TABLE ST W12X26
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 -4.444
PERFORM ANALYSIS
UNIT INCHES KIP
PARAMETER 1
CODE LRFD
* FULLY BRACED CONDITION IS ACHIEVED WITH A UNT OF 1.0 INCH
UNT 1 ALL
MAIN 1 ALL
FYLD 50 ALL
CB 0 ALL
TRACK 2 ALL
SELECT ALL
FINISH
STAAD Output
STAAD.PRO MEMBER SELECTION - (LRFD 3RD EDITION) v1.0 *********************************************** |--------------------------------------------------------------------------| | Y PROPERTIES | |************* | IN INCH UNIT | | * |=============================| ===|=== ------------ | |MEMBER 1 * | AISC SECTIONS | | AX=0.1620E+2 | | * | ST W24X55 | | --Z AY=0.9322E+1 | |DESIGN CODE * | | | AZ=0.4720E+1 | | LRFD 2001 * =============================== ===|=== PY=0.1330E+2 | | * PZ=0.1340E+3 | | * |<---LENGTH (FT)= 30.00 --->| RY=0.1340E+1 | |************* RZ=0.9129E+1 | | | | 499.9 (KIP-FEET) | |PARAMETER | L1 L1 L1 CAPACITIES | |IN KIP INCH | IN KIP INCH | |--------------- + L1 L1 -------------| | KL/R-Y= 268.60 | PNC=0.4791E+2| | KL/R-Z= 39.44 + L1 L1 pnc=0.0000E+0| | UNL = 1.00 | PNT=0.7290E+3| | CB = 1.14 + L1 L1 pnt=0.0000E+0| | PHIC = 0.85 | MNZ=0.6030E+4| | PHIB = 0.90 + mnz=0.5999E+4| | FYLD = 50.00 |L0 L0 MNY=0.5604E+3| | NSF = 1.00 +---+---+---+---+---+---+---+---+---+---| mny=0.0000E+0| | DFF = 0.00 -27.8 VN =0.2517E+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 66.7 0.0 0.0 499.9 | | 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 | | ====================================================== | | PASS LRFD-H1-1B-C 0.995 1 | | 0.00 C 0.00 -499.95 15.00 | |* *| |**************************************************************************| | | |--------------------------------------------------------------------------|