AustraliaAS 4100:2020
Lintel reactions link to the supporting columns and bearings, so changes to the load path propagate downstream automatically. Design angle, T-lintel, or PFC+plate steel lintels to AS 4100:2020 with multiple supports and loads. Capacity and deflection are checked against code references.
Method & scope
Calculation method
The Steel Lintel calculator designs angle, T-lintel, and PFC+plate steel lintels to AS 4100:2020, using limit state (LRFD) design. It models the lintel as a beam with multiple supports and loads, then checks section capacity, member capacity, shear, combined shear-moment interaction, and deflection against serviceability limits.Section types and properties
Three lintel types are supported, each with distinct section property calculations:- Single angle, effective section properties are calculated for bending about the geometric axis, assuming the angle is restrained from lateral deflection and rotation at its supports
- T-lintel, treated as a T-section loaded equally on each of its two flanges, with capacities derived from the combined geometry
- PFC+plate, a parallel flange channel with a welded flat plate; composite section properties are computed from the combined PFC and plate geometry
Moment capacity checks (AS 4100:2020 Cl. 5.1, 5.3, 5.6, 8.4)
The bending demand M* is compared to the effective moment capacity phiM_gov. Section moment capacity M_s is calculated from the reduced section modulus (accounting for yielding and local buckling). Member moment capacity M_b incorporates lateral-torsional buckling using the reference buckling moment and moment modification factors for the unbraced length L_L between lateral restraints. For biaxial bending, the combined check per Cl. 8.4 is applied. utilization = M / (phi × M_gov) ≤ 1.0*Shear capacity (AS 4100:2020 Cl. 5.11) and interaction (Cl. 5.12)
Web shear capacity phi × V_v is based on web yield and shear buckling. Where bending moment and shear are both significant, a shear-moment interaction check is applied per Cl. 5.12. utilization (MV) = interaction ratio ≤ 1.0Flange loading checks
For distributed loads and point loads applied at an eccentricity from the web (e_DL and e_PL), separate flange shear capacity and flange moment capacity checks are performed per AS 4100:2020 Cl. 5.11 and Cl. 5.3/5.6. T-lintels carrying masonry loads typically require these checks.Deflection analysis
Short-term deflection (delta_s), long-term deflection (delta_l), and imposed-load deflection (delta_Q) are each compared to their respective span/limit criteria. The governing load case for each deflection type is identified.Assumptions
Beam is uniform cross-section, net areas equal gross area with maximum allowed holes, bearing limit states are not checked, and all distributed loads are applied at the same eccentricity. For T-lintels, loads are assumed equally distributed to each flange.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.
Steel T-Lintel Calculator: Overview
Steel Lintel PFC + Plate Calculator to AS 4100:2020: Overview
Available presets
Each preset opens the calculator with a typical setup already entered.Common questions
What design standard and method does this calculator use?
What design standard and method does this calculator use?
The calculator uses AS 4100:2020 limit state design (LRFD) for steel lintels over masonry openings. It checks section capacity and member capacity for bending and shear, and deflection against serviceability limits. All checks reference the relevant AS 4100:2020 clauses directly in the output.
What lintel types does the calculator support?
What lintel types does the calculator support?
The calculator covers three lintel section types: single-angle lintels, T-lintels (T-section or back-to-back angles), and PFC+plate composite lintels (parallel flange channel with a welded plate). Each type has its own effective section properties calculated from the input dimensions.
What are the key inputs?
What are the key inputs?
Key inputs are span length, support bearing lengths, lintel section type and dimensions (or selection from the Australian steel section database), steel grade, and applied loads including dead load (masonry self-weight and superimposed loads) and live load. Support conditions can be set as simply supported or with partial fixity.
How does load linking work for lintels?
How does load linking work for lintels?
Reactions at each bearing point can be linked directly to the column or wall element supporting the lintel in the same Calcs.com project. When loads or span geometry change in the lintel, the reactions update and propagate automatically to the connected support calculations, eliminating manual re-entry across the load path.
What deflection limits are applied?
What deflection limits are applied?
The calculator applies serviceability deflection limits in accordance with AS 4100:2020 and AS/NZS 1170.1. The default limits are span/300 for total loads and span/500 for live load only, consistent with common masonry-support requirements to avoid cracking above the opening. These limits can be adjusted to match project specifications.
Next steps
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