Material properties, shared by every verification. The cross-section is not shared: SIA 263 classifies it from the internal forces, so it belongs to each verification and appears with it.
Checks the bending resistance of any steel section at the ultimate limit state, to SIA 263:2013, from its section class and section modulus entered directly. Every step shows its formula and the clause it comes from.
You enter the characteristic yield strength fy,k from table 1 of your copy of SIA 263, the section class, the plastic section modulus Wpl, the resistance factor γM1 and the design bending moment MEd.
You get the governing modulus, the ultimate and design bending resistance, the modulus required and the utilisation with a pass or fail, each with its source. With the Basic plan, it prints as an A4 calculation note.
A class 1 section with Wpl = 628,000 mm³ in fy,k = 235 N/mm², under a design bending moment MEd = 113 kNm. These are the module's own results for its worked example, computed when this page was built.
| Input | Value | Ref. |
|---|---|---|
| Characteristic yield strength fy,k | 235 N/mm² | § t.1 |
| Section class | 1 | § t.4 |
| Plastic section modulus Wpl | 628000 mm³ | |
| Resistance factor γM1 | 1.05 | § 4.1.3 |
| Design bending moment MEd | 113 kNm |
| Step | Value | Ref. |
|---|---|---|
| Characteristic yield strength | fy,k = 235 N/mm² | § t.1 |
| Section classEntered. It decides which modulus enters and nothing else here depends on it. | – = Class 1 | § t.4 |
| Governing section modulusA plastic calculation: MR = fy,k·Wpl. | Wpl = 628,000 mm³ |
| Step | Value | Ref. |
|---|---|---|
| Ultimate bending resistanceMR = fy,k·Wpl | MR = 147.58 kNm | |
| Design bending resistance | MR/γM1 = 140.55 kNm | |
| Section modulus requiredW ≥ γM1·MEd/fy,k, the sizing form of the same check. | Wpl,req = 504,894 mm³ | |
| Bending resistance of the sectionMEd ≤ MR/γM1 | η = 0.804 · Pass80 % of the capacity used |
Verified clause by clause against SIA 263:2013 and against independent calculations used on real projects, before release.
No. The class is entered as it is and nothing checks it. It only decides which section modulus enters the resistance.
Four more checks: shear, which must always be verified because a moment that varies along the member implies a shear force; local buckling; lateral-torsional buckling; and serviceability. The rolled I or H section module makes all of them.
The full calculation is shown on screen, free and without an account. A print-ready A4 calculation note is part of the Basic plan.
Norm: SIA 263:2013 · Page updated: 26 October 2026