Steel beam load capacity calculator

Steel beam check to EN 1993-1-1 — bending, shear, deflection and lateral-torsional buckling. Pick a section, a span and a load.

Example A ready-made example: the inputs are locked. Your own check comes with Hobby; every input, the detailed checks with formulas and the calculation report come with Pro.

Hobby The check runs on the server: every “Check” and “Find” uses 1 of your monthly calculations (shared with 1D and 2D cutting). Every input, the formulas and the report come with Pro.

Input

Example

Structural system

Span L

span between support centrelines

Permanent load G without self-weight

total over the length: decking, screed, cladding, services

Load Q

total over the whole length, uniformly distributed

Deflection limit

Additional loads Pro

Characteristic values (without γ). G is permanent, Q imposed: imposed loads are placed span by span and on the overhangs in the most unfavourable way. a, b and x from the left end.

Load per area work out Q from kg/m² and the beam spacing

Use — imposed load

Beam spacing

centre to centre of the neighbouring beams; for an edge beam — half of it plus the deck overhang

Permanent layers — deck, screed, finishes (optional)

If the deck or slab is continuous over the beam, an inner beam takes up to 1.25 times more — then enter 1.25 × the spacing.

Section

Find a section

Type e.g. IPE 160, HEA 200, L 50x5. Arrows to choose, Enter to confirm.

Section type

Size

Lateral restraint

Is the compression flange restrained?

Yes — decking, panels or ribs fixed to the flange along the whole length No — only at the supports

The compression flange is the top flange of a simply supported beam (the bottom one of a cantilever). Without a restraint, a long beam can bend sideways and twist (lateral-torsional buckling) under a smaller load. If you are not sure, choose “No”.

National annex

Steel and partial factors Pro

Steel grade

γG — permanent loads

γQ — imposed load Q

γM0 — resistance

γM1 — buckling

Hobby treats the whole load Q as imposed (γQ = 1.50) — on the safe side. A separate permanent load G is in Pro.

Hobby uses S235, γG = 1.35, γQ = 1.50 and γM0 = γM1 = 1.00 (EN recommended values). Own values in Pro.

E = 210,000 N/mm² and g = 9.81 m/s² are fixed; fy to EN 1993-1-1, Table 3.1 (t ≤ 40 mm).

Is the section sufficient?

ExampleIPE 200 · simply supported · S235

YES, 85 % utilised

Governing: lateral-torsional buckling

Utilisation per check

Bending48 %
Shear13 %
Deflection42 %
Lateral-torsional buckling85 %

Lateral-torsional buckling is checked: the beam is held against twisting at the supports; the load is on the top flange.

Your own check comes with Hobby or Pro.

Scope and limitations

Lateral-torsional buckling (the beam bends sideways and twists) is checked to EN 1993-1-1, 6.3.2 with the critical moment of the beam. Not covered: loads acting upwards (wind), sheeting as a continuous elastic restraint, a cantilever continuing beyond its support, and cold-formed sections (EN 1993-1-3).
U and L sections are not symmetric about the load — the load must act through the shear centre, or the section must be restrained against twisting.
L sections: bending about the axis parallel to the horizontal leg (not a principal axis), with Wel. This is valid only if the angle is restrained against lateral deflection and twisting — for beams and cantilevers alike. Without restraint the deflection is about 1.5× and the stresses about 1.3× larger.
Point load P(x): the moments and shear forces from P and from the self-weight are added conservatively (in a simply supported beam their maxima are not at the same section); the M–V interaction under the force (EN 1993-1-1, 6.2.8) is included.
Cold-formed U sections with t = 3 mm have a class 4 flange and are checked with Weff; distortional buckling and web crippling at the support or under the load (EN 1993-1-3) are not checked.
Web bearing at the supports and under a point load (EN 1993-1-5, section 6) is not checked. In short, heavily loaded beams it can govern — add stiffeners where needed.
Shear buckling of the web is not checked: the shear resistance is taken to EN 1993-1-1, 6.2.6 with η = 1.0. For hw/tw > 72ε/η (η = 1.2 to EN 1993-1-5) the calculator shows a warning — a check to EN 1993-1-5, section 5 is then required.
Moving load (force P): the check is static only. For hoists and cranes, a dynamic factor and EN 1991-3 / EN 1993-6 apply; local bending of the bottom flange under the trolley wheels is not checked.
The results are for guidance only — important structures must be checked by a qualified structural engineer.

Find a section

The lightest section that passes every check for the span, load and restraint you entered.

Pro: ranking of all 18 families with filters for depth and wall thickness, the force P and a link to the weight and price calculator.

Pro: cantilever, fixed-end, fixed–pinned, overhanging and continuous beams, loads on a part and point loads, separate permanent and imposed loads, restraints and load level for buckling, detailed checks with diagrams, reactions, Qmax, point load P(x) and moving load (also a two-wheel trolley), web bearing with stiffeners, natural frequency, S420 and S460 steels, calculation report and saved calculations.Unlock with Pro

Detailed checks

Pro

Bending, shear, deflection and lateral-torsional buckling with the formulas, the section class and which W is used.

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Reactions and maximum load

Pro

Support reactions, the anchor moment and Qmax for every check.

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Saved calculations

Pro

Save your calculations and open them again.

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Point load P(x)

Pro

The allowed force at any point of the beam — chart and table. Moving load: enter your own force, move it or play it along the span and see YES/NO live.

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Web bearing and stiffeners

Pro

The web under the support reactions and the point loads to EN 1993-1-5, section 6, with the bearing length you enter — and stiffeners where the web is not enough.

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Natural frequency

Pro

The first natural frequency of the beam, with guidance limits for floors, footbridges and gyms.

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