V. AISC 360-10 W LTB Test F.1-2
Verify the lateral-torsional buckling flexural strength of a wide flange section that is braced at the third points per the LRFD and ASD methods of the AISC 360-10 code.
References
- American Institute of Steel Construction. 2010 Steel Construction Manual. Fourteenth Edition. AISC: Chicago, IL.
-
American Institute of Steel Construction. 2011. Design Examples, Version 14.0. AISC:Chicago, IL. Example F.1-2A and F.1-2B, pp. F9 - F11
Note: This reference is freely available for download from the AISC website at https://www.aisc.org/globalassets/aisc/university-programs/teaching-aids/first-semester-design-examples.pdf
Details
From reference (2):
Verify the available flexural strength of the W18×50, ASTM A992 beam selected in Example F.1-1A with the beam braced at the ends and third points.
Results
| Result Type | Reference | STAAD.Pro | Difference | Comments |
|---|---|---|---|---|
| ϕbMn (ft·k) [LRFD] | 305 | 306 | negligible | |
| Mn/Ωb (ft·k) [ASD] | 203 | 203 | none |
STAAD.Pro Input
The file C:\Users\Public\Public Documents\STAAD.Pro CONNECT Edition\Samples\ Verification Models\09 Steel Design\US\AISC\AISC 360-10 W LTB Test F.STD is typically installed with the program.
STAAD SPACE
START JOB INFORMATION
ENGINEER DATE 06-Feb-19
END JOB INFORMATION
INPUT WIDTH 79
UNIT FEET KIP
JOINT COORDINATES
1 0 0 0; 2 35 0 0;
MEMBER INCIDENCES
1 1 2;
DEFINE MATERIAL START
ISOTROPIC STEEL
E 4.176e+06
POISSON 0.3
DENSITY 0.489024
ALPHA 6.5e-06
DAMP 0.03
TYPE STEEL
STRENGTH RY 1.5 RT 1.2
END DEFINE MATERIAL
MEMBER PROPERTY AMERICAN
1 TABLE ST W18X50
CONSTANTS
MATERIAL STEEL ALL
SUPPORTS
2 FIXED BUT FX MZ
1 FIXED BUT MZ
LOAD 1 LOADTYPE None TITLE LOAD CASE 1
MEMBER LOAD
1 UNI GY -0.45
LOAD 2 LOADTYPE None TITLE LOAD CASE 2
MEMBER LOAD
1 UNI GY -0.75
LOAD COMB 3 COMBINATION LOAD CASE 3
1 1.2 2 1.6
LOAD COMB 4 COMBINATION LOAD CASE 4
1 1.0 2 1.0
PERFORM ANALYSIS
PRINT ANALYSIS RESULTS
LOAD LIST 3
PARAMETER 1
CODE AISC UNIFIED 2010
METHOD LRFD
FU 9360 ALL
FYLD 7200 ALL
CB 1.01 ALL
LX 11.67 ALL
UNB 11.67 ALL
UNT 11.67 ALL
TRACK 2 ALL
CHECK CODE ALL
LOAD LIST 4
PARAMETER 2
CODE AISC UNIFIED 2010
METHOD ASD
FU 9360 ALL
FYLD 7200 ALL
CB 1.01 ALL
LX 11.67 ALL
UNB 11.67 ALL
UNT 11.67 ALL
TRACK 2 ALL
CHECK CODE ALL
FINISH
STAAD.Pro Output
STAAD.PRO CODE CHECKING - (AISC-360-10-LRFD) v1.4a ******************************************** ALL UNITS ARE - KIP FEET (UNLESS OTHERWISE Noted) MEMBER TABLE RESULT/ CRITICAL COND/ RATIO/ LOADING/ FX MY MZ LOCATION ======================================================================= 1 ST W18X50 (AISC SECTIONS) PASS Eq. H1-1b 0.872 3 0.00 0.00 -266.44 17.50 |-----------------------------------------------------------------------| | SLENDERNESS | | Actual Slenderness Ratio : 254.294 L/C : 3 | | Allowable Slenderness Ratio : 300.000 LOC : 17.50 | |-----------------------------------------------------------------------| | STRENGTH CHECKS | | Critical L/C : 3 Ratio : 0.872(PASS) | | Loc : 17.50 Condition : Eq. H1-1b | |-----------------------------------------------------------------------| | DESIGN FORCES | | Fx: 0.000E+00( ) Fy: 0.000E+00 Fz: 0.000E+00 | | Mx: 0.000E+00 My: 0.000E+00 Mz: -2.664E+02 | |-----------------------------------------------------------------------| | SECTION PROPERTIES (UNIT: INCH) | | Azz: 8.550E+00 Ayy: 6.390E+00 Cw: 3.046E+03 | | Szz: 8.889E+01 Syy: 1.069E+01 | | Izz: 8.000E+02 Iyy: 4.010E+01 Ix: 1.240E+00 | |-----------------------------------------------------------------------| | MATERIAL PROPERTIES | | Fyld: 7199.999 Fu: 9359.999 | |-----------------------------------------------------------------------| | Actual Member Length: 35.000 | | Design Parameters | | Kz: 1.00 Ky: 1.00 NSF: 1.00 SLF: 1.00 CSP: 12.00 | |-----------------------------------------------------------------------| | SECTION CLASS UNSTIFFENED / λ λp λr CASE | | STIFFENED | | Compression : Non-Slender 6.58 N/A 13.49 T.B4.1(a)-1 | | Slender 45.23 N/A 35.88 T.B4.1(a)-5 | | Flexure : Compact 6.58 9.15 24.08 T.B4.1(b)-10 | | Compact 45.23 90.55 137.27 T.B4.1(b)-15 | STAAD SPACE -- PAGE NO. 7 STAAD.PRO CODE CHECKING - (AISC-360-10-LRFD) v1.4a ******************************************** ALL UNITS ARE - KIP FEET (UNLESS OTHERWISE Noted) |-----------------------------------------------------------------------| | CHECK FOR AXIAL TENSION | | | | FORCE CAPACITY RATIO CRITERIA L/C LOC | | Yield 0.00E+00 6.61E+02 0.000 Eq. D2-1 3 0.00 | | Rupture 0.00E+00 7.17E+02 0.000 Eq. D2-2 3 0.00 | |-----------------------------------------------------------------------| | CHECK FOR AXIAL COMPRESSION | | | | FORCE CAPACITY RATIO CRITERIA L/C LOC | | Maj Buck 0.00E+00 5.09E+02 0.000 Eq. E7-1 3 0.00 | | Min Buck 0.00E+00 5.14E+01 0.000 Eq. E7-1 3 0.00 | | Flexural | | Tor Buck 0.00E+00 4.81E+02 0.000 Eq. E7-1 3 0.00 | | Intermediate | | Results Eff Area KL/r Fcr Fe Pn | | Maj Buck 9.88E-02 56.93 5.54E+03 1.27E+04 5.65E+02 | | Min Buck 1.02E-01 254.29 5.59E+02 6.37E+02 5.71E+01 | | Flexural Ag Fcr Pn | | Tor Buck 9.97E-02 5.24E+03 5.34E+02 | |-----------------------------------------------------------------------| | CHECK FOR SHEAR | | | | FORCE CAPACITY RATIO CRITERIA L/C LOC | | Local-Z 0.00E+00 2.31E+02 0.000 Eq. G2-1 3 0.00 | | Local-Y 3.05E+01 1.92E+02 0.159 Eq. G2-1 3 0.00 | | Intermediate | | Results Aw Cv Kv h/tw Vn | | Local-Z 5.94E-02 1.00 1.20 6.58 2.56E+02 | | Local-Y 4.44E-02 1.00 0.00 45.23 1.92E+02 | |-----------------------------------------------------------------------| | CHECK FOR BENDING-YIELDING | | | | FORCE CAPACITY RATIO CRITERIA L/C LOC | | Major 2.66E+02 3.79E+02 0.703 Eq. F2-1 3 17.50 | | Minor 0.00E+00 6.23E+01 0.000 Eq. F6-1 3 0.00 | | Intermediate Mn My | | Major 4.21E+02 0.00E+00 | | Minor 6.92E+01 0.00E+00 | |-----------------------------------------------------------------------| | CHECK FOR BENDING-LATERAL TORSIONAL BUCKLING | | | | FORCE CAPACITY RATIO CRITERIA L/C LOC | | Major 2.66E+02 3.06E+02 0.872 Eq. F2-2 3 17.50 | | Intermediate Mn Me Cb Lp Lr Lb | | Major 3.39E+02 0.00E+00 1.01 5.83 16.97 11.67 | STAAD SPACE -- PAGE NO. 8 STAAD.PRO CODE CHECKING - (AISC-360-10-LRFD) v1.4a ******************************************** ALL UNITS ARE - KIP FEET (UNLESS OTHERWISE Noted) |-----------------------------------------------------------------------| | CHECK FOR FLEXURE TENS/COMP INTERACTION | | RATIO CRITERIA L/C LOC | | Flexure Comp 0.872 Eq. H1-1b 3 17.50 | | Flexure Tens 0.872 Eq. H1-1b 3 17.50 | | Intermediate Mcx Mrx Pc | | Mcy Mry Pr | | Flexure Comp 3.06E+02 2.66E+02 5.14E+01 | | 6.23E+01 0.00E+00 0.00E+00 | | Flexure Tens 3.06E+02 2.66E+02 6.61E+02 | | 6.23E+01 0.00E+00 0.00E+00 | |-----------------------------------------------------------------------| 52. LOAD LIST 4 53. PARAMETER 2 54. CODE AISC UNIFIED 2010 55. METHOD ASD 56. FU 9360 ALL 57. FYLD 7200 ALL 58. CB 1.01 ALL 59. LX 11.67 ALL 60. UNB 11.67 ALL 61. UNT 11.67 ALL 62. TRACK 2 ALL 63. CHECK CODE ALL STEEL DESIGN STAAD SPACE -- PAGE NO. 9 STAAD.PRO CODE CHECKING - ( AISC-360-10-ASD) v1.4a ******************************************** ALL UNITS ARE - KIP FEET (UNLESS OTHERWISE Noted) MEMBER TABLE RESULT/ CRITICAL COND/ RATIO/ LOADING/ FX MY MZ LOCATION ======================================================================= 1 ST W18X50 (AISC SECTIONS) PASS Eq. H1-1b 0.904 4 0.00 0.00 -183.75 17.50 |-----------------------------------------------------------------------| | SLENDERNESS | | Actual Slenderness Ratio : 254.294 L/C : 4 | | Allowable Slenderness Ratio : 300.000 LOC : 17.50 | |-----------------------------------------------------------------------| | STRENGTH CHECKS | | Critical L/C : 4 Ratio : 0.904(PASS) | | Loc : 17.50 Condition : Eq. H1-1b | |-----------------------------------------------------------------------| | DESIGN FORCES | | Fx: 0.000E+00( ) Fy: 0.000E+00 Fz: 0.000E+00 | | Mx: 0.000E+00 My: 0.000E+00 Mz: -1.838E+02 | |-----------------------------------------------------------------------| | SECTION PROPERTIES (UNIT: INCH) | | Azz: 8.550E+00 Ayy: 6.390E+00 Cw: 3.046E+03 | | Szz: 8.889E+01 Syy: 1.069E+01 | | Izz: 8.000E+02 Iyy: 4.010E+01 Ix: 1.240E+00 | |-----------------------------------------------------------------------| | MATERIAL PROPERTIES | | Fyld: 7199.999 Fu: 9359.999 | |-----------------------------------------------------------------------| | Actual Member Length: 35.000 | | Design Parameters | | Kz: 1.00 Ky: 1.00 NSF: 1.00 SLF: 1.00 CSP: 12.00 | |-----------------------------------------------------------------------| | SECTION CLASS UNSTIFFENED / λ λp λr CASE | | STIFFENED | | Compression : Non-Slender 6.58 N/A 13.49 T.B4.1(a)-1 | | Slender 45.23 N/A 35.88 T.B4.1(a)-5 | | Flexure : Compact 6.58 9.15 24.08 T.B4.1(b)-10 | | Compact 45.23 90.55 137.27 T.B4.1(b)-15 | STAAD SPACE -- PAGE NO. 10 STAAD.PRO CODE CHECKING - ( AISC-360-10-ASD) v1.4a ******************************************** ALL UNITS ARE - KIP FEET (UNLESS OTHERWISE Noted) |-----------------------------------------------------------------------| | CHECK FOR AXIAL TENSION | | | | FORCE CAPACITY RATIO CRITERIA L/C LOC | | Yield 0.00E+00 4.40E+02 0.000 Eq. D2-1 4 0.00 | | Rupture 0.00E+00 4.78E+02 0.000 Eq. D2-2 4 0.00 | |-----------------------------------------------------------------------| | CHECK FOR AXIAL COMPRESSION | | | | FORCE CAPACITY RATIO CRITERIA L/C LOC | | Maj Buck 0.00E+00 3.39E+02 0.000 Eq. E7-1 4 0.00 | | Min Buck 0.00E+00 3.42E+01 0.000 Eq. E7-1 4 0.00 | | Flexural | | Tor Buck 0.00E+00 3.20E+02 0.000 Eq. E7-1 4 0.00 | | Intermediate | | Results Eff Area KL/r Fcr Fe Pn | | Maj Buck 9.88E-02 56.93 5.54E+03 1.27E+04 5.65E+02 | | Min Buck 1.02E-01 254.29 5.59E+02 6.37E+02 5.71E+01 | | Flexural Ag Fcr Pn | | Tor Buck 9.97E-02 5.24E+03 5.34E+02 | |-----------------------------------------------------------------------| | CHECK FOR SHEAR | | | | FORCE CAPACITY RATIO CRITERIA L/C LOC | | Local-Z 0.00E+00 1.54E+02 0.000 Eq. G2-1 4 0.00 | | Local-Y 2.10E+01 1.28E+02 0.164 Eq. G2-1 4 0.00 | | Intermediate | | Results Aw Cv Kv h/tw Vn | | Local-Z 5.94E-02 1.00 1.20 6.58 2.56E+02 | | Local-Y 4.44E-02 1.00 0.00 45.23 1.92E+02 | |-----------------------------------------------------------------------| | CHECK FOR BENDING-YIELDING | | | | FORCE CAPACITY RATIO CRITERIA L/C LOC | | Major 1.84E+02 2.52E+02 0.729 Eq. F2-1 4 17.50 | | Minor 0.00E+00 4.14E+01 0.000 Eq. F6-1 4 0.00 | | Intermediate Mn My | | Major 4.21E+02 0.00E+00 | | Minor 6.92E+01 0.00E+00 | |-----------------------------------------------------------------------| | CHECK FOR BENDING-LATERAL TORSIONAL BUCKLING | | | | FORCE CAPACITY RATIO CRITERIA L/C LOC | | Major 1.84E+02 2.03E+02 0.904 Eq. F2-2 4 17.50 | | Intermediate Mn Me Cb Lp Lr Lb | | Major 3.39E+02 0.00E+00 1.01 5.83 16.97 11.67 | STAAD SPACE -- PAGE NO. 11 STAAD.PRO CODE CHECKING - ( AISC-360-10-ASD) v1.4a ******************************************** ALL UNITS ARE - KIP FEET (UNLESS OTHERWISE Noted) |-----------------------------------------------------------------------| | CHECK FOR FLEXURE TENS/COMP INTERACTION | | RATIO CRITERIA L/C LOC | | Flexure Comp 0.904 Eq. H1-1b 4 17.50 | | Flexure Tens 0.904 Eq. H1-1b 4 17.50 | | Intermediate Mcx Mrx Pc | | Mcy Mry Pr | | Flexure Comp 2.03E+02 1.84E+02 3.42E+01 | | 4.14E+01 0.00E+00 0.00E+00 | | Flexure Tens 2.03E+02 1.84E+02 4.40E+02 | | 4.14E+01 0.00E+00 0.00E+00 | |-----------------------------------------------------------------------|