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United StatesAISC 360-22 (LRFD)

Steel Beam (LRFD)

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Beam reactions link to the columns and footings below, so load changes propagate downstream automatically. Design hot-rolled steel beams to AISC 360-22 LRFD with multiple spans and loads. Checks bending (Chapter F), shear (Chapter G), and three deflection limits with the governing ASCE 7 combination identified for each.
The Calcs.com steel beam calculator to AISC 360-22 (LRFD) enables the fast design and analysis of a steel beam with multiple supports and loads using LRFD provisions. Engineers can quickly and easily model any type of steel beam, including steel floor and roof beams with a handy range of presets that reduce repetitive data entry and improve accuracy. Loads can be dynamically linked between structural elements, so beams, columns, and connections can easily be linked and checked for adequacy.

Method & scope

Calculation method

The Steel Beam (LRFD, AISC 360-22) calculator performs a full strength and serviceability check per the current AISC Specification on hot-rolled steel beams with any number of spans and loads.
Section classification (AISC 360-22 B4)
Flanges and webs are classified as compact, noncompact, or slender by comparing width-to-thickness ratios to lambda_p and lambda_r limits. The classification governs which capacity equations are used in Chapter F and determines whether reduction factors for FLB or WLB apply.
Flexural capacity, AISC 360-22 Chapter F
Positive and negative bending are checked independently. For compact sections: utilization = Mu / (phi × Mp) ≤ 1.0. For sections with noncompact or slender elements, flange local buckling and web local buckling reductions reduce the available strength. Lateral-torsional buckling is evaluated using the unbraced length Lb, limiting lengths Lp and Lr, and the Cb moment gradient factor. The governing flexural capacity is the minimum from all applicable limit states.
Shear capacity, AISC 360-22 Chapter G
Web shear capacity uses: utilization = Vu / (phi × 0.6 Fy Aw Cv1) ≤ 1.0. For standard W-shapes with h/tw ≤ 2.24√(E/Fy), phi = 1.0 and Cv1 = 1.0. For deeper webs or non-standard sections, phi = 0.9 and Cv1 is calculated from web slenderness.
Load combination analysis
All ASCE 7-22 LRFD strength combinations are evaluated with FEA. The calculator identifies the governing combination for moment and for shear separately. Unfactored load cases are also run for deflection calculations.
Deflection checks
Three deflection limits are tracked independently:
  • Instantaneous deflection, compared to L/n span ratio or absolute limit (typically L/360 for live load)
  • Long-term deflection, includes sustained load creep effect; typically L/240
  • Simplified DL+(LL or SL) deflection, combined loading for total deflection assessment
utilization = delta / delta_allow ≤ 1.0 for each criterion. The critical (worst-case) result across all load cases is shown in the summary.
Inputs summary
Geometry: section designation, yield strength Fy (ksi), plan length, span lengths, support types, incline pitch, tributary spacing. Loads: dead, live, roof live, snow, wind as uniform, partial, point, or moment loads at any position. Design criteria: separate deflection limits for each of the three serviceability checks.
Outputs summary
Summary outputs include critical moment demand and capacity, governing load combination for moment and shear, shear demand and capacity, maximum factored reactions (vertical and horizontal), and deflection ratios for all three criteria. Reactions are structured for automatic load linking to connected column and footing calculations.

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.

Available presets

Each preset opens the calculator with a typical setup already entered.

Common questions

This calculator uses the Load and Resistance Factor Design (LRFD) method per AISC 360-22, the current edition of the AISC Specification for Structural Steel Buildings. Factored strength demands are compared to phiRn resistance values per Chapters F and G.
Key inputs include the steel section (W, S, C, HSS, angle, or custom), yield strength Fy, span lengths and support conditions, applied loads (dead, live, snow, wind) with tributary widths, unbraced length for LTB, and deflection limit criteria for live load, total, and DL+(LL or SL) checks.
The calculator checks factored moment demand versus capacity (AISC 360-22 Chapter F), factored shear versus capacity (Chapter G), and three deflection limits. The summary shows the governing ASCE 7 load combination for moment and shear, support reactions for load linking, and deflection ratios for all three serviceability criteria.
Yes, the calculator supports simple spans, continuous spans, and cantilevers with unlimited supports and loads. Point loads, uniform loads, partial uniform loads, and moment loads can all be applied. All ASCE 7 LRFD combinations are evaluated and the governing case is identified automatically.
Use this calculator when your project uses strength-based LRFD load combinations per ASCE 7 (1.2D+1.6L etc.). Use steelBeamASDAISC360-22 if your project uses allowable stress design with service-level ASD combinations (D+L etc.). Both calculators reference AISC 360-22, only the design philosophy and load factors differ.
Yes, beam reactions at supports link directly to connected column and footing calculations in the same project. When span length, loads, or member size changes, all connected calculations update automatically, no manual re-entry.

Next steps

US Steel Beam - Interpreting & Optimizing Results

US Steel Beam - Interpreting & Optimizing Results

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