Check steel beam capacity for flexure, shear, and lateral-torsional buckling per AISC 360-22. Use for W, S, or HSS beam selection and capacity verification.
Check steel beam capacity for flexure, shear, and lateral-torsional buckling per AISC 360-22. Outputs: moment capacity φMn, shear capacity φVn, deflection, LTB check, DCR.
Governing Code Standard: AISC 360-22 Ch. F, G.
Calculations support dual units (SI metric and US Imperial). Outputs include demand-capacity ratios (DCR), step-by-step formula substitutions, parametric SVG technical drawings, and exportable calculation sheets. Free to use with no account or sign-up required.
LTB occurs when an unbraced steel beam buckles laterally and rotates. AISC 360-22 Chapter F divides LTB into three zones: plastic (Lb ≤ Lp), inelastic (Lp < Lb ≤ Lr), and elastic (Lb > Lr), each with a different moment capacity equation.
Per AISC 360-22 Section F2, Lp = 1.76 ry √(E/Fy), where ry is the weak-axis radius of gyration. For Lb ≤ Lp, the full plastic moment Mp = FyZx controls.
Per AISC 360-22 Section G2.1, for most W-shapes (h/tw ≤ 2.24√(E/Fy)), φVn = 1.0 × 0.6Fy × Aw, where Aw = d × tw is the web area. φ = 1.0 for this condition.
LRFD uses factored loads (1.2D + 1.6L) and φ factors (φ = 0.9 for flexure). ASD uses service loads with an Ω factor (Ω = 1.67). Both approaches yield similar results when load factors are correctly applied.
Deflection is a serviceability check using unfactored service loads. Limits: L/360 for floors under live load, L/240 for wind or combined loads. The moment of inertia Ix from the AISC Steel Manual tables is used in the elastic deflection formula.
AISC 360-22 §F — W-shape flexural design
This calculation is for preliminary design verification only. All results must be independently verified by a licensed professional engineer before use in construction documents.