Steel Column (LRFD, AISC 360-16)

Design hot-rolled steel columns and posts to AISC 360-16 LRFD. Checks cover axial section capacity, flexural and flexural-torsional buckling, and combined axial-plus-bending interaction. Column axial load links from beam reactions above and passes down to footing calculations below so the full load path updates automatically.

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. ## Method & scope | Property | Detail | | ---------------- | ----------------------------------------------------------------------------------------------------------------------------- | | Design standards | AISC 360-16 (LRFD) | | Regions | United States | | Presets | Generic Concentrically-Loaded Column, Interior Isolated Column, Exposed Outdoor Isolated Column | | What it checks | Structural analysis, Axial compression capacity, Flexural capacity, Combined axial compression and bending, Axial deformation | #### Calculation method The Steel Column (LRFD, AISC 360-16) calculator designs hot-rolled steel columns and posts using Load and Resistance Factor Design. It runs a first-order structural analysis to determine demands, then applies AISC 360-16 capacity equations for all relevant limit states. ##### Structural analysis The calculator performs FEA on the column as a beam-column, resolving axial forces, moments, and deflections under applied loads. End conditions (pinned, fixed, roller) are specified at each support. Concentrated axial loads and distributed lateral loads can be applied at any height. A first-order moment amplification factor accounts for P-delta (P-little delta) effects, and the member is assumed to be part of a braced frame. ##### Axial compression capacity Nominal compressive strength is determined per AISC 360-16 Chapter E: **utilization = Pu / (phi\_c \* Pn) ≤ 1.0** where phi\_c = 0.90. The nominal strength Pn is governed by flexural buckling about the weak axis for most standard shapes, using the effective slenderness ratio KL/r and the critical stress Fcr. For singly-symmetric and unsymmetric sections, flexural-torsional buckling is also checked. Slender element reduction factors (Q) are applied where local buckling governs the section capacity. ##### Flexural capacity When moments are present from eccentricity or lateral loads, flexural strength is checked per AISC 360-16 Chapter F: **utilization = |Mu| / (phi\_b \* Mn) ≤ 1.0** where phi\_b = 0.90. The lateral-torsional buckling limit state governs for unbraced lengths exceeding Lp. Compact, non-compact, and slender web and flange classifications are evaluated per Table B4.1b. ##### Combined axial compression and bending For members carrying both axial compression and bending the AISC H1-1 interaction equations are applied: * For Pu / phi\_c Pn ≥ 0.2: (Pu / phi\_c Pn) + (8/9) \* (Mux / phi\_b Mnx + Muy / phi\_b Mny) ≤ 1.0 * For Pu / phi\_c Pn \< 0.2: (Pu / 2 phi\_c Pn) + (Mux / phi\_b Mnx + Muy / phi\_b Mny) ≤ 1.0 Both strong- and weak-axis moment demands are included, allowing the full biaxial bending case to be assessed. ##### Axial deformation Axial shortening under the design load is calculated and reported alongside the capacity checks, allowing serviceability limits to be verified where column shortening is relevant to the structural system. ##### Outputs Results are displayed as traffic-light utilization ratios for each limit state. Code clause references are shown for every check. The governing utilization ratio, critical load combination, and section properties are summarized at the top of the results panel. ## 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 The calculator uses Load and Resistance Factor Design (LRFD) per AISC 360-16. Factored load demands are compared against phi-reduced nominal capacities for axial compression, flexure, and combined loading. Key inputs include column height, end conditions (pinned, fixed, roller), axial loads with optional eccentricity, distributed lateral loads, and effective length factors Kx and Ky. The steel section is selected from the AISC database of W-shapes, HSS, pipes, and angles, or entered as a custom section. The calculator checks axial compressive strength (flexural buckling and flexural-torsional buckling where applicable), strong- and weak-axis flexural strength, and combined axial compression plus biaxial bending interaction per AISC 360-16 Chapter H. Yes. Under eccentric loading or lateral loads the column is designed for combined axial-plus-bending per the AISC H1-1a/H1-1b interaction equations. Both strong- and weak-axis moment demands are included in the interaction check. Kx and Ky are entered directly as inputs. Common values (pin-pin = 1.0, fix-pin = 0.7, fix-fix = 0.5) are referenced in the code documentation. For sway frames, higher K-factors should be applied per the alignment chart method or a rational analysis. Yes, column axial load can be linked from beam reaction outputs above, and the resulting column base reaction links to a footing or base plate calculation below. Changes propagate automatically across the full load path. ## 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 columns and posts to AISC 360-22 (LRFD). Multiple end fixities with traffic-light checks for moment, axial, and deformation. Design hot-rolled steel columns and posts to AISC 360-16 (ASD). An earlier code edition, kept for existing projects. Design hot-rolled steel columns and posts to AISC 360-22 (ASD). Checks axial compression, flexural buckling and combined axial and bending. Design steel beams to AISC 360-16 (ASD) with multiple supports and loads. An earlier code edition, kept for existing projects. Validation and design examples for steel columns to the 2016 AISC Specification, compared with AISC Companion examples.