A beam does not have a fixed load capacity based on its type alone. Profile, material, span, support points and load together determine the outcome.
Why “how many kilos does this beam carry?” is not complete
A load in the middle has a different effect than the same weight evenly distributed across the beam. The distance between the support points also counts. It must be clear whether the beam is supported laterally, how the connections work and which floor or wall rests on it. Without that data, a number in kilos is not a useful selection aid. Ask for a calculation that clearly identifies the situation, load combinations and conditions.
Steel beams: IPE, HEA, HEB and other profiles
IPE profiles have an I-shape; HEA and HEB belong to the wide flange family. There are also HEM, older INP/IPN profiles, U-profiles, tubes and composite beams. The profile name and nominal height are not a complete strength description. Use the exact one cross section-properties from the appropriate product data and the established steel quality. The effect on the strong or weak axis and the possibilities for connections make a difference.
Wooden beams and engineered wood products
Solid construction wood, laminated wood, LVL and wooden I-beams have different properties and product specifications. The strength class, fiber direction, moisture conditions and duration of load may be relevant. With existing beams, deterioration, cracks and previous nicks also play a role. A type of wood such as spruce or Douglas does not yet indicate the full constructive quality. For composite products, supplier information and permitted detail are required.
Concrete beams and prestressed parts
Bee reinforced concrete determine, among other things concrete quality, reinforcement, geometry and bearing resistance. Prestressed beams contain applied prestressing forces and cannot be treated like any solid concrete beam. Cuts, shortenings and damage require a specific assessment. An external dimension without reinforcement or product data is insufficient to determine the load-bearing capacity. For prefab parts, the calculation must match the delivered system.
Strength, stability and deformation
De maatgevende controle is niet altijd dezelfde. A beam can have sufficient resistance when bent, but bend too much, deflect sideways or have insufficient support capacity. Connections and the wall or column below must be able to accommodate the reactions. The structural engineer checks the relevant combinations and states the necessary conditions. A percentage utilization in one table is therefore only meaningful together with the assessed component and the control described.
What information does the structural engineer need?
Collect the free span, support lengths, exact cross-section, material data and position of all loads. Indicate the floor or roof structure and any overlying walls. Show how the beam is supported laterally and where it connects to existing buildings. Add photos when the existing situation differs from the drawing. Also record the intended use, so that a future storage floor is not unnoticed as a residential floor.
Read load capacity in a report
Ask what design load may be applied and under what conditions. Forces are often expressed in kN, distributed loads in kN/m and moments in kNm. A material property or cross-sectional value is not the same as the allowable load on the complete beam. Have the outcome translated into the actual floor structure, point loads and usage situation. Only use the profile for ordering when connections and supports have also been coordinated.
Your preparation in four steps
- Note profile, quality and span
- Draw point loads and distributed loads
- Check support points and connections
- Order based on the final design
Frequently asked questions on this topic
Does an HEB always carry more than an IPE?
A separate profile name is insufficient for that conclusion. The exact dimensions, material, load direction, support and span must be compared.
Is a wooden beam of the same size equally strong?
Not automatically. Strength class, condition, load duration and moisture conditions may vary.
Can an online bar table replace my calculation?
Only if all application conditions can be demonstrably agreed can a table within a design be useful. It does not automatically cover connections, stability and underlying structures.
View the associated structural calculation, create your preparation list or take the guides and checklists along to the consultation.
What types of beams are there?
| Beam type | Common application | Necessary for load-bearing capacity |
|---|---|---|
| IPE | Floor and roof beam | Exact profile, steel quality, lateral support |
| HEA / HEB / HIM | Beam, portal, column | Exact section series, forces, buckling and lateral-torsional buckling conditions |
| INP/IPN | Including existing steel construction | Actual profile data and condition |
| UPN/UPE | Edge beam or composite part | Connection, rotation and load position |
| RHS/SHS/CHS | Tube or tube in supporting frames | Wall thickness, quality and connections |
| Welded plate girder | Customization and larger span | Plates, welds, stiffeners and stability |
| Solid construction wood | Beam layer, purlin | Strength class, sizes, moisture and load duration |
| Glued laminated timber | Girders and trusses | Product class, geometry and connections |
| LVL | Beams, edges, composite applications | Product construction and direction |
| Wooden I-beam | Light floor and roof construction | Supplier tables and savings conditions |
| Reinforced concrete | Foundation and building beams | Concrete, reinforcement and supports |
| Prestressed concrete | Prefab supporting parts | Product specification and prestressing |
View all constructions and construction guides · All types of structural calculations
Why the span matters so much
The calculation example below only compares proportions for an ideal freely supported beam with the same cross-section, the same material and the same evenly distributed line load q. It is not a load capacity table and does not provide a safe beam size.
Relative influence of a longer span
| Span | Bending moment | Elastic deflection |
|---|---|---|
| L | 1 × | 1 × |
| 1.5L | 2,25 × | 5,06 × |
| 2 L | 4 × | 16 × |
For this specific model, M = qL²/8 and δ = 5qL⁴/(384EI). The table only shows the effect of L if q, E and I remain the same. Other supports, point loads, stability and connections require different or additional checks. A larger span here also means more total load, because q remains the same.
Sources and further checking
More information: NEN: standards for constructive assessment.