V. IS 801-Column with axial and major axis bending
Verification example for a cold-formed column subject to axial compression and bending moment according to IS:801-1975.
Details
Verifies the calculations for an IS 60CS40x4 (channel with lips) column that is 2 m long and subject to axial compression and major axis bending moment. This example checks for compression, shear, bending, and compression and bending interaction as per IS 801.
- E = 2,074,000 kgf/cm2 = 203,400 MPa
- Fy = 3,569 kgf/cm2 = 353.0 MPa
- Fu = 4,588 kgf/cm2 = 450 MPa
- G = 795,000 kgf/cm2 = 77,963 MPa
- P = 10 kN
- Mz = 4.0 kN·m
- Vy = 2 kN
Calculations
Verification
Section Dimension Checks
Flanges (ref. cl 5.2.3):
w/t = 2 / 0.4 = 5 < 60, Hence OK
Web (ref. cl 5.2.4):
W/t = (6 - 2×0.4 - 2× 0.6) / 0.4 = 10 < 500 and
h/t = (6 - 2× 0.4) / 0.4 = 13 < 150, Hence OK
Check for limiting slenderness (ref. cl 6.3.3):
Hence, OK
Allowable Compression Strength
Maximum allowable compressive stress for flexural buckling Y (ref. cl 6.6.1.1 of IS 801)
Design stress, F = 0.6× fy = 2,160 kgf/cm2 = 211.8 MPa
Effective width of flange, Beff
Effective width of web, Beff
Factor, Q = Aeff / A = 1.0=
Slenderness limit
Maximum allowable compressive stress for flexural torsional buckling (ref. cl 6.6.1.2 of IS 801)
Polar radius of gyration,
The allowable compressive stress, Fa is the minimum of Fa1 and Fa1 .
Allowable Bending Strength
C = 1.0 for member under combined axial and bending.
Maximum allowable compressive stress:
Allowable Shear Strength
The allowable shear stress, Fv is the minimum of Fv1 and Fv2 :
Fv = 1,440 kgf/cm2 = 141.3 MPaAxial and Bending Interaction
Hence, not OK
Results
| Result Type | Reference | STAAD.Pro | Difference | Comments |
|---|---|---|---|---|
| Allowable compressive stress (MPa) | 55.32 | 55.371 | negligible | |
| Allowable bending stress (MPa) | 211.8 | 211.854 | negligible | |
| Allowable unbraced bending stress (MPa) | 138.5 | 138.583 | negligible | |
| Allowable shear stress along Y (MPa) | 141.3 | 141.236 | negligible | |
| Axial and Bending interaction | 2.103 | 2.102 | negligible |
Input
The file C:\Users\Public\Public Documents\STAAD.Pro 2026\Samples \Verification Models\09 Steel Design\India\IS 801 - Column with axial and major axis bending.STD is typically installed with the program.
STAAD
STAAD SPACE
START JOB INFORMATION
ENGINEER DATE 18-Mar-19
END JOB INFORMATION
INPUT WIDTH 79
UNIT METER KN
JOINT COORDINATES
1 0 0 0; 2 0 2 0;
MEMBER INCIDENCES
1 1 2;
DEFINE MATERIAL START
ISOTROPIC STEEL
E 2.05e+08
POISSON 0.3
DENSITY 76.8195
ALPHA 1.2e-05
DAMP 0.03
TYPE STEEL
STRENGTH RY 1.5 RT 1.2
END DEFINE MATERIAL
MEMBER PROPERTY COLDFORMED INDIAN
1 TABLE ST 60CS40X4
CONSTANTS
MATERIAL STEEL ALL
SUPPORTS
1 FIXED
LOAD 1 LOADTYPE None TITLE LOAD CASE 1
JOINT LOAD
2 FX 2 FY -10
PERFORM ANALYSIS PRINT STATICS CHECK
PARAMETER 1
CODE IS801
TRACK 2 ALL
CHECK CODE ALL
PRINT MEMBER PROPERTIES ALL
FINISH
Output
STAAD.Pro CODE CHECKING - ( IS:801 ) v3.0
***********************
ALL UNITS ARE IN - METE KN (U.N.O.)
|-----------------------------------------------------------------------------|
| MEMBER: 1 SECTION: 60CS40X4 LEN: 2.000 LOC: 0.000 |
| STATUS: FAIL RATIO: 3.071 REF: 6.3 LTB LC: 1 |
|-----------------------------------------------------------------------------|
| DESIGN FORCES: |
| Fx:(C) 10.000 Fy: 2.000 Fz: 0.000 |
| Mx: 0.000 My: 0.000 Mz: 4.000 |
|-----------------------------------------------------------------------------|
| SECTION PROPERTIES: (Unit: CM) |
| Ag: 5.82000 Az: 3.20000 Ay: 3.36000 |
| Cz: 1.75000 Cy: 3.00000 Z0: 4.46000 |
| Iz: 28.20000 Iy: 12.30000 J: 0.29600 |
| Sz: 9.40000 Sy: 5.46000 |
| Rz: 2.20122 Ry: 1.45375 Cw: 162.00003 |
|-----------------------------------------------------------------------------|
| MATERIAL INFO: (Unit: MPa) |
| Fy: 353.090 Fu: 449.993 E: 203404.356 G: 77968.401 |
| Fya(compression): 353.090 Fya(bending): 353.090 |
|-----------------------------------------------------------------------------|
| DESIGN PROPERTIES: |
| Member Length: 2.000 Lz: 2.000 Ly: 2.000 Lb: 2.000 |
| DESIGN PARAMETERS: |
| Kz: 1.000 Ky: 1.000 NSF: 1.000 Cb: 0.000 |
|-----------------------------------------------------------------------------|
| CRITICAL SLENDERNESS: |
| Actual: 137.575 Allowable: 200.000 Ratio: 0.688 |
|-----------------------------------------------------------------------------|
| CHECKS: | Stresses | |
| | Loc. | Demand | L/C | Actual | Allow |Ratio | Ref CL |
| |(MET) |(KN-MET)| | (MPa) | (MPa) | | |
|--------------|------|--------|------|----------|----------|------|----------|
| Tension | - | - | - | - | 211.854 | - | 6.1 |
| Compression | 0.000| 10.00| 1| 17.183 | 55.371 | 0.310| 6.6.1.1 |
| BendZComp | 0.000| 4.00| 1| 425.562 | 211.854 | 2.009| 6.3 |
| BendZTens | 0.000| 4.00| 1| 425.562 | 211.854 | 2.009| 6.3 |
| BendUnbraced | 0.000| 4.00| 1| 425.562 | 138.583 | 3.071| 6.3 LTB |
| BendYComp | - | - | - | - | 211.854 | - | 6.3 |
| BendYTens | - | - | - | - | 211.854 | - | 6.3 |
| Bend Web | 0.000| 4.00| 1| 368.820 | 211.854 | 1.741| 6.4.2 |
| Shear Z | - | - | - | - | 141.236 | - | 6.4.1 |
| Shear Y | 0.000| 2.00| 1| 5.953 | 141.236 | 0.042| 6.4.1 |
| Axial+Bend | 0.000| - | 1| - | - | 2.102| 6.7.2(a)2|
| Bend+Shear | 0.000| - | 1| - | - | 0.020| 6.4.3 |
|-----------------------------------------------------------------------------|
| Effective Section Properties:(cm) |
| Ae: 5.820 SzTop: 9.400 SzBot: 9.400 SyLeft: 7.029 SyRight: 5.467 |
| Intermediate Results: Cb = 1.000 |
|-----------------------------------------------------------------------------|
NOTE: Torsion has not been considered in the design.
STAAD SPACE -- PAGE NO. 5