Steel Member (Design Only - ASD, AISC 360-16)
Run the calcMember reactions link to connected column or footing calculations automatically, change a load and everything downstream updates. Design steel members to AISC 360-16 ASD with combined axial and bending interaction, lateral-torsional buckling, and flexural buckling checks. For projects on the 2016 specification using allowable strength design.
This calculator uses an earlier code edition (AISC 360-16). It stays available for existing projects. For new designs, check the Calculator Library for the current edition.
Method & scope
Calculation method
The Steel Member (Design Only, ASD, AISC 360-16) calculator takes ASD (service-level) design forces from analysis and evaluates all member capacity limit states using allowable strength design safety factors per AISC 360-16.ASD safety factors
In ASD, available strengths are divided by a safety factor Omega (typically 1.67 for tension yielding, 1.67 for flexure, 1.67 for compression). The demand-to-capacity ratio is expressed as Pa/Pc (axial), Ma/Mc (flexure), or Va/Vc (shear), where each allowable value equals the nominal strength divided by the appropriate Omega factor. All interaction equations use these ASD available strengths.Section classification
Plate element slenderness ratios are compared to the limiting values from AISC 360-16 Table B4.1. Compact, non-compact, and slender classifications are applied automatically. Slender elements trigger effective area reductions for compression and modified flexural equations for bending.Flexural capacity and lateral-torsional buckling
Chapter F provisions determine the nominal flexural strength Mn. For doubly-symmetric I-shapes, the plastic moment Mp is the upper limit. Lateral-torsional buckling reduces Mn when Lb exceeds Lp. The calculator computes:- Lb ≤ Lp: no LTB reduction, Mn = Mp
- Lp < Lb ≤ Lr: linear LTB interpolation
- Lb > Lr: elastic LTB governs
Compression and column buckling
Chapter E compression checks cover flexural buckling about both axes and torsional or flexural-torsional buckling as required by section type. The slenderness ratio KL/r is evaluated for each axis and the critical stress Fcr is used to compute the nominal compression strength Pn. The ASD allowable compression is: Pc = Pn / Omega_c (where Omega_c = 1.67) For slender sections, an effective area Aeff accounts for local buckling.Combined actions interaction
Chapter H ASD interaction equations form the core output. For high axial ratio (Pa/Pc ≥ 0.2): interaction ratio = Pa/Pc + (8/9)(Max/Mcx + May/Mcy) ≤ 1.0 For low axial ratio (Pa/Pc < 0.2): interaction ratio = Pa/(2Pc) + (Max/Mcx + May/Mcy) ≤ 1.0 Each term breaks down the axial and bending contributions, making it easy to see which drives the design. The governing equation is identified and all required and available strengths are shown alongside the code clause.P-delta and stability
A first-order moment amplification factor is applied within the member for P-delta effects, consistent with the assumption of a braced frame. Frame-level second-order effects should be verified separately before using this calculator for sway-sensitive structures.Shear
Chapter G shear provisions determine the allowable shear force. The web shear coefficient Cv is used to compute Vn, and the ASD allowable shear is Vc = Vn / Omega_v (Omega_v = 1.67). For compact webs Cv = 1.0.How to use it
1
Open the calculator
Open it from Run calc in the About this calculator panel above. To start from a typical setup, choose one of the presets listed there.
2
Enter your inputs
Work through the input sections from top to bottom. Click any input label to see its reference explanation, clause, conditions and assumptions. See Checks, References, Conditions and Assumptions.
3
Review the results and export
Check the utilization of each governing check in the summary, then export a PDF report. See Views and Export.
Common questions
What design method and code does this calculator use?
What design method and code does this calculator use?
This calculator uses the Allowable Strength Design (ASD) method to AISC 360-16, the 2016 edition of the AISC Specification for Structural Steel Buildings. For the newer AISC 360-22 edition using ASD, use the steelMemberASDAISC360-22 calculator instead.
What are the key inputs?
What are the key inputs?
You provide the steel section (W, HSS, pipe, channel, or angle), member length, effective length factors or unbraced lengths for each axis, and the unfactored (ASD) design forces, axial load, major- and minor-axis bending moments, and shear. Forces can be entered manually or linked from an upstream analysis or beam calculator.
What limit states does it check?
What limit states does it check?
The calculator checks yielding and lateral-torsional buckling for flexure (Chapter F), flexural and torsional buckling for compression (Chapter E), tensile yielding and rupture (Chapter D), shear (Chapter G), and the combined axial plus bending interaction equations from AISC 360-16 Chapter H, using ASD safety factors (Omega) throughout.
Can it handle combined axial load and biaxial bending?
Can it handle combined axial load and biaxial bending?
Yes. The Chapter H ASD interaction equations handle members under combined axial force and bending about one or both axes. The calculator evaluates both the high-axial and low-axial forms and reports the controlling interaction ratio with the governing equation reference.
How do I set effective length factors and unbraced lengths?
How do I set effective length factors and unbraced lengths?
You enter K factors for strong- and weak-axis buckling separately and set the unbraced length Lb for lateral-torsional buckling. The calculator derives Lp and Lr from section properties automatically. A first-order moment amplification factor accounts for P-delta effects within the member, consistent with the braced-frame assumption.
Can this member calculation link to beam and footing calculations?
Can this member calculation link to beam and footing calculations?
Yes, the member calc receives reactions from upstream calculations (e.g. frame analysis) and passes base reactions to footing or base plate calculations. Changes propagate automatically through the load path.
Next steps
Calculator Library
Complete list of Calcs.com design calculators available for United States projects (AISC, ACI, NDS, ASCE 7, IBC, and related standards).
Design a Steel Member (Design Only - ASD) to AISC 360-22
Design steel members to AISC 360-22 (ASD). Input analysis forces to check combined axial, bending, and shear interaction for US hot-rolled sections.
Design a Steel Member (Design Only - LRFD) to AISC 360-16
Design steel members to AISC 360-16 (LRFD) from analysis forces. An earlier code edition, kept for existing projects.
Design a Steel Member (Design Only - LRFD) to AISC 360-22
Design steel members to AISC 360-22 (LRFD). Input analysis forces to check combined axial, bending, and shear for US hot-rolled and HSS sections.
Design a Steel Beam (ASD) to AISC 360-16
Design steel beams to AISC 360-16 (ASD) with multiple supports and loads. An earlier code edition, kept for existing projects.
Link Design Calculators to Truss & Portal Frame Analysis
Link Design Only calculators to Truss Analysis and Portal Frame Analysis results to check member capacity against the analysis forces.