V. AISI 2016 CU Nominal and Local Axial Capacity
Determine the nominal axial capacity and local axial capacity of a 72-Inch-long member subjected to axial compression load.
Details
The member is a 6' simply-supported span subject to a 1 kip axial load. The section used is a 800CU125-68 channel without lips.
- Depth: D = 8.25 in
- Width: B = 1.25 in
- Thickness: t = 0.0713 in
- Inner radius: R = 0.1069 in
- Area: A = 0.748 in2
- Moment of inertia about major axis: Ix = 6.0 in4
- Moment of inertia about minor axis: Iy = 0.0703 in4
- Torsional constant: J = 0.00127 in4
- Distance between centroid and shear center: x0 = -0.427 in
- Radius of gyration about major axis:
- Radius of gyration about minor axis:
- Polar radius of gyration:
- Warping constant: Cw = 0.92 in6
Validation
Section Dimension Checks
Radius to thickness ratio:
Width to thickness ratio:
Depth to thickness ratio:
Nominal Strength of Global Buckling
From Cl. E.2 of AISI S100-16:
Since: ,
Allowable nominal axial strength (ASD):
Design nominal axial strength (LRFD):
Local Buckling Interacting with Lateral-Torsional Buckling
From Cl. E.3.1 of AISI S100-16:
Flange elements:
(Eq 1.3-7, Appendix 1 of AISI S100-16) |
Therefore, calculation of the effective width is not required.
Web element:
Effective area,
Allowable local axial strength (ASD):
Design local axial strength (LRFD):
Results
Result Type | Reference | STAAD.Pro | Difference | Comments |
---|---|---|---|---|
Allowable nominal axial strength, ASD (kips) | 1.891 | 1.891 | none | |
Allowable local axial strength, ASD (kips) | 2.893 | 2.893 | none | |
Design nominal axial strength, LRFD (kips) | 1.830 | 1.830 | none | |
Design local axial strength, LRFD (kips) | 2.801 | 2.800 | negligible |
STAAD.Pro Input
The file C:\Users\Public\Public Documents\STAAD.Pro 2023\Samples \Verification Models\09 Steel Design\US\AISI\AISI 2016 CU Nominal and Local axial Capacity.STD is typically installed with the program.
STAAD SPACE
START JOB INFORMATION
ENGINEER DATE 02-Jun-20
END JOB INFORMATION
INPUT WIDTH 79
UNIT FEET KIP
JOINT COORDINATES
1 0 0 0; 2 6 0 0;
MEMBER INCIDENCES
1 1 2;
UNIT INCHES KIP
DEFINE MATERIAL START
ISOTROPIC STEEL
E 29000
POISSON 0.3
DENSITY 0.000283
ALPHA 6.5e-06
DAMP 0.03
TYPE STEEL
STRENGTH RY 1.5 RT 1.2
END DEFINE MATERIAL
MEMBER PROPERTY COLDFORMED AMERICAN
1 TABLE ST 800CU125-68
CONSTANTS
MATERIAL STEEL ALL
SUPPORTS
1 PINNED
2 FIXED BUT MY MZ
LOAD 1 LOADTYPE None TITLE LOAD CASE 1
MEMBER LOAD
1 CON GX -1 0
1 CON GX 1 72
PERFORM ANALYSIS
PARAMETER 1
CODE AISI 2016
FYLD 50 ALL
METHOD LRFD
TRACK 2 ALL
CHECK CODE ALL
PARAMETER 2
CODE AISI 2016
FYLD 50 ALL
METHOD ASD
TRACK 2 ALL
CHECK CODE ALL
FINISH
STAAD.Pro Output
STAAD SPACE -- PAGE NO. 3 STAAD.Pro CODE CHECKING - (AISI S100-16) [LRFD] (v1.0) ******************************************************** ALL UNITS ARE IN "INCH" AND "KIP " (U.N.O.) |-----------------------------------------------------------------------------| | MEMBER: 1 SECTION:ST 800CU125-68 LEN: 72.000 LOC: 0.000 | | STATUS: PASS RATIO: 0.357 REF: Sec. E3 LC: 1 | |-----------------------------------------------------------------------------| | DESIGN FORCES: | | Location: 0.000 Criteria: Sec. E3 LC: 1 | | Fx:(C) 1.000 Fy: -0.000 Fz: -0.000 | | Mx: 0.000 My: -0.000 Mz: -0.000 | |-----------------------------------------------------------------------------| | SECTION PROPERTIES: | | Ag: 0.74800 Az: 0.15284 Ay: 0.56281 | | Cz: 0.17700 Cy: 4.12500 | | Iz: 6.00000 Iy: 0.07030 J: 0.00127 | | Sz: 1.45455 Sy: 0.06552 | | Rz: 2.83221 Ry: 0.30657 Cw: 0.92000 | |-----------------------------------------------------------------------------| | MATERIAL INFO: | | Fy: 50.000 Fu: 58.000 E: 29000.000 G: 11300.000 | |-----------------------------------------------------------------------------| | DESIGN PROPERTIES: | | Member Length: 72.000 Lz: 72.000 Ly: 72.000 Lb: 0.000 | | DESIGN PARAMETERS: | | Kz: 1.000 Ky: 1.000 NSF: 1.000 | |-----------------------------------------------------------------------------| | CRITICAL SLENDERNESS: | |-----------------------------------------------------------------------------| | LC : 1 Actual : 234.858 Allowable : 200.000 Ratio : 1.174 | |-----------------------------------------------------------------------------| | Section Dimension Check | Ratio | Limit | Status | |-----------------------------------------------------------------------------| | Radius To Thickness Ratio | 1.499 | 10.000 | PASS | | Width To Thickness Ratio | 15.032 | 60.000 | PASS | | Web Depth To Thickness Ratio | 110.710 | 200.000 | PASS | |-----------------------------------------------------------------------------| STAAD SPACE -- PAGE NO. 4 STAAD.Pro CODE CHECKING - (AISI S100-16) [LRFD] (v1.0) ******************************************************** ALL UNITS ARE IN "INCH" AND "KIP " (U.N.O.) | - MEMBER: 1 (Contd.....) | | | |-----------------------------------------------------------------------------| | Limit States | Load# |Location| Demand | Capacity |Ratio| Reference | |--------------------|-------|--------|----------|----------|-----|-----------| | Tension | - | - | - | 32.538 | - |Sec. D3 | | Yielding | - | - | - | 33.660 | - |Sec. D2 | | Rupture | - | - | - | 32.538 | - |Sec. D3 | | Compression | 1 | 0.00 | -1.000 | 2.800 |0.357|Sec. E3 | | Local Comp | 1 | 0.00 | -1.000 | 2.800 |0.357|Sec. E3 | | Axial Comp | 1 | 0.00 | -1.000 | 2.893 |0.346|Sec. E2 | | Bending | - | - | - | 2.913 | - |Sec. F3 | | Major Local Bend | - | - | - | 14.316 | - |Sec. F3 | | Minor Local Bend | - | - | - | 2.913 | - |Sec. F3 | | Major Sectional | - | - | - | 65.455 | - |Sec. F2 | | Minor Sectional | - | - | - | 2.948 | - |Sec. F2 | | LTB Major | - | - | - | 14.311 | - |Sec. F2 | | Shear | - | - | - | 4.356 | - |Sec. G2 | | Major Shear (Z) | - | - | - | 4.356 | - |Sec. G2 | | Minor Shear (Y) | - | - | - | 6.107 | - |Sec. G2 | | Interaction | 1 | 0.00 | - | - |0.357|Eq. H1.2-1 | | (Bend+Comp) | 1 | 0.00 | - | - |0.357|Eq. H1.2-1 | |-----------------------------------------------------------------------------| 40. PARAMETER 2 41. CODE AISI 2016 42. FYLD 50 ALL 43. METHOD ASD 44. TRACK 2 ALL 45. CHECK CODE ALL STEEL DESIGN WARNING # 8 ~ The specified value of FU for member # 1 seems out of range. Reset back to default value. STAAD SPACE -- PAGE NO. 5 STAAD.Pro CODE CHECKING - (AISI S100-16) [ASD ] (v1.0) ******************************************************** ALL UNITS ARE IN "INCH" AND "KIP " (U.N.O.) |-----------------------------------------------------------------------------| | MEMBER: 1 SECTION:ST 800CU125-68 LEN: 72.000 LOC: 0.000 | | STATUS: PASS RATIO: 0.546 REF: Sec. E3 LC: 1 | |-----------------------------------------------------------------------------| | DESIGN FORCES: | | Location: 0.000 Criteria: Sec. E3 LC: 1 | | Fx:(C) 1.000 Fy: -0.000 Fz: -0.000 | | Mx: 0.000 My: -0.000 Mz: -0.000 | |-----------------------------------------------------------------------------| | SECTION PROPERTIES: | | Ag: 0.74800 Az: 0.15284 Ay: 0.56281 | | Cz: 0.17700 Cy: 4.12500 | | Iz: 6.00000 Iy: 0.07030 J: 0.00127 | | Sz: 1.45455 Sy: 0.06552 | | Rz: 2.83221 Ry: 0.30657 Cw: 0.92000 | |-----------------------------------------------------------------------------| | MATERIAL INFO: | | Fy: 50.000 Fu: 58.000 E: 29000.000 G: 11300.000 | |-----------------------------------------------------------------------------| | DESIGN PROPERTIES: | | Member Length: 72.000 Lz: 72.000 Ly: 72.000 Lb: 0.000 | | DESIGN PARAMETERS: | | Kz: 1.000 Ky: 1.000 NSF: 1.000 | |-----------------------------------------------------------------------------| | CRITICAL SLENDERNESS: | |-----------------------------------------------------------------------------| | LC : 1 Actual : 234.858 Allowable : 200.000 Ratio : 1.174 | |-----------------------------------------------------------------------------| | Section Dimension Check | Ratio | Limit | Status | |-----------------------------------------------------------------------------| | Radius To Thickness Ratio | 1.499 | 10.000 | PASS | | Width To Thickness Ratio | 15.032 | 60.000 | PASS | | Web Depth To Thickness Ratio | 110.710 | 200.000 | PASS | |-----------------------------------------------------------------------------| STAAD SPACE -- PAGE NO. 6 STAAD.Pro CODE CHECKING - (AISI S100-16) [ASD ] (v1.0) ******************************************************** ALL UNITS ARE IN "INCH" AND "KIP " (U.N.O.) | - MEMBER: 1 (Contd.....) | | | |-----------------------------------------------------------------------------| | Limit States | Load# |Location| Demand | Capacity |Ratio| Reference | |--------------------|-------|--------|----------|----------|-----|-----------| | Tension | - | - | - | 21.692 | - |Sec. D3 | | Yielding | - | - | - | 22.395 | - |Sec. D2 | | Rupture | - | - | - | 21.692 | - |Sec. D3 | | Compression | 1 | 0.00 | -1.000 | 1.830 |0.546|Sec. E3 | | Local Comp | 1 | 0.00 | -1.000 | 1.830 |0.546|Sec. E3 | | Axial Comp | 1 | 0.00 | -1.000 | 1.891 |0.529|Sec. E2 | | Bending | - | - | - | 1.938 | - |Sec. F3 | | Major Local Bend | - | - | - | 9.525 | - |Sec. F3 | | Minor Local Bend | - | - | - | 1.938 | - |Sec. F3 | | Major Sectional | - | - | - | 43.549 | - |Sec. F2 | | Minor Sectional | - | - | - | 1.962 | - |Sec. F2 | | LTB Major | - | - | - | 9.522 | - |Sec. F2 | | Shear | - | - | - | 2.866 | - |Sec. G2 | | Major Shear (Z) | - | - | - | 2.866 | - |Sec. G2 | | Minor Shear (Y) | - | - | - | 4.018 | - |Sec. G2 | | Interaction | 1 | 0.00 | - | - |0.546|Eq. H1.2-1 | | (Bend+Comp) | 1 | 0.00 | - | - |0.546|Eq. H1.2-1 | |-----------------------------------------------------------------------------|