This calculator follows the procedures and guidelines of the American Institute of Steel Construction (AISC) Specification of Structural Steel Buildings - Allowable Stress Design and Plastic Design - 9th Edition 1989 (AISC 360).
It calculates actual and allowable stresses in members when subjected to axial load and/or uniaxial or biaxial bending. Therefore it is applicable to both beams and columns. The final result is computed as a Stress Ratio (S.R) of actual stress to allowable stress. A member with S.R ≤ 1 is deemed adequate against strength checks.
❗ This calculation has been written in accordance with AISC 360.
Common steel sections in ASIC
Calculation
Technical Notes
Inputs
Member Properties
Fy, ksi
:50
d
:15in
tw
:2in
bf
:10in
tf
:0.5in
Loads
P
:235kips
Mx, ft-kips
:20
My, ft-kips
:5
Design Parameters for Compression Design
Kx
:1
Ky
:1
Lx
:10ft
Ly
:5ft
Lb
:5ft
Design Parameters for Flexural Design
Cb
:1
Cmx
:-1
Cmy
:-1
ASIF
:1
Note on ASIF
'ASIF' is a multiplier of any of the calculated allowable stresses Fa, Fbx and Fby and the Euler column buckling stresses F’ex and F’ey. It appears only when calculating the Stress Ratio (S.R) where a value of 1.0 is typically used.
Output
Member Properties
Cross-sectional area
:38.0
rt
:2.11453644277324
J
:40.8333333333333
Cw, in.^6
:4870.79166666668
Lc
:8.956685895029583
Lu
:11.111111111111084
Lb/rt
:28.375013448011
X-Axis
Sx
:131.088888888889in3
Ix
:983.166666666666
rx
:5.08653192436102
Y-Axis
Sy
:18.5333333333333in3
Iy
:92.6666666666667
ry
:1.56160061834903
Capacity Checks
Axial (Compression / Tension)
Kx*Lx/rx
:23.5917127395351
Ky*Ly/ry
:38.4221159334797
Cc
:106.99879020467306
fa, ksi
:6.18421052631579
Fa, ksi
:26.051462689272455
Pa, kips
:989.955582192355
fa/Fa
:0.2373843879738212
:PASS
Axial tension
Allowable tension stress, Ft (ksi)
:30
:NA
Flexure (X-Axis)
fbx, ksi
:1.83081878284455
Fbx, ksi
:32.4289321881345
Mrx, ft-kips
:354.25605736630666
F'ex, ksi
:268.307127907887
fbx/Fbx
:0.05645633880952863
fbx<Fbx?
:PASS
Flexure (Y-Axis)
fby, ksi
:3.23741007194245
Fby, ksi
:36.0723304703363
Mry, ft-kips
:55.71171039307483
F'ey, ksi
:101.15528945027
fby/Fby
:0.08974773821737689
fby<Fby?
:PASS
Combined Check (Stress Ratio)
Stress ratio
:0
:PASS
Explanation
The American and British Standards method for design is to compare "allowable stresses" against "actual stresses", where actual stresses are based upon characteristic loads with an overall Factor of Safety (FoS).
The design checks to ACI 360R-22 are based upon ensuring:
actual stress≤FoSallowable stress
Compression Check
Column's slenderness ratio (KL/r) is a key parameter in calculating the allowable stress, and is defined as the ratio of its effective length (KL) and radius of gyration (r). These values vary depending on the axis considered (major / minor).
Actual compressive stress is calculated by:
fa=AF
The formula varies depending on whether the column is buckling elastically or inelastically, and is determined by the factor Cc:
Cc=Fy2π2E
For calculating the allowable axial compressive stress, Fa:
For calculating allowable resisting moment (Mr) and Euler stress (F'e):
Mr=12FbSFe′=23(KLr12)212Ep2
Buckling due to bending
Combined Check (Stress Ratio)
The Stress Ratio (S.R.) checks against the combined actions of axial and flexure. A steel section with S.R. ≤ 1 is deemed safe against strength checks.