Steel Beam (LRFD, AISC 360-16)

Beam reactions link to the columns and footings below, so load changes propagate downstream automatically. Design hot-rolled steel beams to AISC 360-16 LRFD with multiple spans and loads. Checks bending (Chapter F), shear (Chapter G), and three deflection limits with the governing load combination shown for each.

This calculator uses an earlier code edition (AISC 360-16 (LRFD)). It stays available for existing projects. For new designs, check the [Calculator Library](/docs/calculators/us) for the current edition. ## Worked example See [Worked Example: Steel Beam to AISC 360-16](/docs/running-calculations/example-calculations/us/worked-example-steel-beam) for a full worked example with this calculator. ## Method & scope | Property | Detail | | ---------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | Design standards | AISC 360-16 (LRFD) | | Regions | United States | | Presets | Generic Beam, Floor Joist, Floor Girder, Ceiling Joist, Hip / Valley, Rafter, Ridge Beam, Roof Header, and 3 more | | What it checks | Section classification (AISC 360-16 B4), Flexural capacity, AISC 360-16 Chapter F, Shear capacity, AISC 360-16 Chapter G, Load combination analysis, Deflection checks | #### Calculation method The Steel Beam (LRFD, AISC 360-16) calculator performs a full LRFD strength and serviceability check on hot-rolled steel beams with any number of spans and loads. ##### Section classification (AISC 360-16 B4) Before any capacity is computed, flanges and webs are classified as compact, noncompact, or slender based on width-to-thickness ratios (lambda) compared to lambda\_p and lambda\_r limits. Classification determines which capacity equations apply in Chapter F. ##### Flexural capacity, AISC 360-16 Chapter F Positive and negative bending capacities are calculated separately. For compact sections the limit state is plastic moment: **utilization** = Mu / (phi × Mp) ≤ 1.0. For noncompact and slender sections, flange local buckling (FLB) and web local buckling (WLB) reductions are applied. Lateral-torsional buckling (LTB) governs when the unbraced length Lb exceeds Lp; the calculator interpolates between Lp and Lr and applies the Cb factor to account for moment gradient. The governing moment capacity is the minimum of yielding, FLB, WLB, and LTB limit states. ##### Shear capacity, AISC 360-16 Chapter G Shear capacity uses the web shear coefficient Cv1 or Cv2 depending on web slenderness. For most W-shapes Cv1 = 1.0 and capacity is: **utilization** = Vu / (phi × 0.6 Fy Aw Cv1) ≤ 1.0 where phi = 1.0. ##### Load combination analysis All ASCE 7 LRFD strength combinations are evaluated (1.4D; 1.2D+1.6L; 1.2D+1.6S+0.5L; etc.). The calculator runs FEA for each combination and identifies the governing case for moment and shear separately. Factored support reactions are reported for each combination. ##### Deflection checks Three serviceability deflection limits are tracked independently: * **Instantaneous deflection**, configurable as L/n or an absolute value; typically L/360 for live load on floor beams * **Long-term deflection**, includes creep-amplified dead load and sustained live load; typically L/240 * **Simplified DL+(LL or SL) deflection**, combined dead plus live or snow for camber assessment The critical (maximum) deflection across all unfactored load cases is compared to each limit: **utilization** = delta / delta\_allow ≤ 1.0. ##### Inputs summary Key geometry and section inputs: section designation, yield strength Fy (ksi), beam plan length, span lengths, support conditions, incline pitch, side length for inclined beams, and center-to-center tributary spacing. Load inputs: dead, live, roof live, snow, and wind loads as uniform, partial, point, or moment loads. Design criteria: individual deflection limit criteria for each of the three deflection checks. ##### Outputs summary The summary panel reports critical moment demand and capacity, governing load combination for moment and shear, shear demand and capacity, maximum factored vertical and horizontal reactions, and all three deflection ratios. Support reactions are formatted for direct load linking to column and footing calculations below. ## How to use it 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. 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](/docs/running-calculations/checking-results/checks-references-conditions-assumptions). Check the utilization of each governing check in the summary, then export a PDF report. See [Views and Export](/docs/running-calculations/exporting-reports/views-and-export). ## Common questions This calculator uses the Load and Resistance Factor Design (LRFD) method per AISC 360-16. Factored demands from ASCE 7 load combinations are compared against factored capacities (phi × Mn, phi × Vn) for each limit state. Key inputs include the steel section designation (W, S, C, HSS, angle, or custom), yield strength (Fy), span lengths, support conditions, applied loads (dead, live, snow, wind, seismic) with tributary widths, and deflection limit criteria for live load, total load, and DL+(LL or SL). The calculator checks factored moment demand versus moment capacity (AISC 360-16 Chapter F), factored shear versus shear capacity (Chapter G), and three deflection criteria, instantaneous live load, long-term, and simplified DL+(LL or SL). The summary shows the governing load combination for moment and shear, support reactions, and deflection ratios. Yes, the calculator supports simple spans, continuous spans, and cantilevers with unlimited supports and loads. Lateral-torsional buckling capacity is computed per AISC 360-16 Chapter F based on the unbraced length Lb, limiting lengths Lp and Lr, and the section's elastic LTB modifier (Cb factor). Section classification (compact, noncompact, slender) is checked per Chapter B4. Use this calculator when your project references AISC 360-16 or when the authority having jurisdiction requires the 2016 edition. For new projects adopting the current edition, use the steelBeamAISC360-22 calculator. The two versions use the same design approach; the 2022 edition includes minor updates to section classification and LTB provisions. 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 Complete list of Calcs.com design calculators available for United States projects (AISC, ACI, NDS, ASCE 7, IBC, and related standards). Design and analyze steel beams to AISC 360-22 (LRFD) with multiple supports and loads. Presets for floor and roof beams cut repetitive data entry. Design hot-rolled steel beams to AISC 360-22 (ASD) with multiple spans and service-level loads. Checks bending, shear and three deflection limits. Design closed-section steel beams under torsion to AISC 360-16 (ASD). An earlier code edition, kept for existing projects. Design closed-section steel beams under torsion to AISC 360-22 (ASD), checking combined bending, shear and torsion per Chapter H. Validation and design examples for steel beams to the 2016 AISC Specification, compared with Calcs.com results. US Steel Beam - Interpreting & Optimizing Results Worked example: a two-span continuous interior steel beam carrying a concrete slab and office live load, designed to AISC 360-16.