Steel member in tension to SIA 263

Checks the resistance of a steel section to an axial tensile force at the ultimate limit state, to SIA 263:2013: the gross section, and the net section where there are holes. Every step shows its formula and the clause it comes from.

What it checks

• Gross area A, clause 1.1: the full area of the bar with no deduction for holes, entered directly or as a flat bar b · t.
• Plastic axial resistance N_Rd = f_y,k · A/γ_M1, equation (38). Under a centred axial force every fibre reaches f_y,k together, so the elastic and plastic limits coincide.
• Gross area required A_req ≥ γ_M1 · N_Ed/f_y,k, the sizing form of equation (38).
• Net section, equation (39), when there are holes in the tension length. It carries f_u, γ_M2 and the factor 0.9, and often governs even where the area lost is small.
• Verification, clause 5.1.2.1: N_Ed ≤ N_Rd, the form E_d ≤ R_d of equation (1).
• Imposed axial force from a restrained temperature change, clause 2.3.3, as an option.

What you enter and what you get

You enter f_y,k from table 1 of your copy of SIA 263, for the grade and the plate thickness; every grade drops by 20 to 30 N/mm² once the thickness passes 40 mm. Then the gross area, directly or from the width b and thickness t of a flat bar; whether there are holes in the tension length; γ_M1 (clause 4.1.3, 1.05); the design tensile force N_Ed (clause 5.1.2) as a magnitude; and the restrained thermal action: not considered, the upper bound of a fully restrained member, or the force from the global analysis.

You get the gross area, the resistance, the area required, the utilisation with a pass or fail, and the clause of each step. With the Basic plan, it prints as an A4 calculation note.

Assumptions and limits

• The module is written for tension throughout; no sign is entered. A member that can also go into compression is checked separately for buckling under clause 4.5.1.
• The section class does not enter. Clause 4.3.1.3 classifies the compressed parts only, clause 5.3.2 reduces the area to A_eff for class 4 in compression only, and clause 5.2.2 sends class 3 back to clause 5.1.2 unchanged. A bar that is class 4 in compression keeps its full resistance in tension.
• SIA 263 has one resistance factor γ_M1 for resistance and stability; it did not carry over the split between γ_M0 and γ_M1 that SN EN 1993-1-1 makes.
• Clause 2.3.4 allows imposed forces from restrained deformation to be neglected in a structural safety check in general.
• Not covered: the connections, block tearing and shear in the net section (clause 6.2.4), bending from an angle connected through one leg, tension through the thickness and lamellar tearing (clause 3.2.1.4), fatigue (clause 4.7), the steel quality against brittle fracture (annex A) and the elongation. Deformations are computed on the gross section under clause 4.10.2.2, without deducting the holes.

Worked example

A flat bar 80 × 12 mm in f_y,k = 235 N/mm², with no holes in the tension length, γ_M1 = 1.05 and a design tensile force of 200 kN, without thermal action. These are the module's own results for its worked example, computed when this page was built.

How this module is verified

Verified clause by clause against SIA 263:2013 and against independent calculations used on real projects, before release.

Questions

Why is the section class not needed?

Classification guards against local buckling of compressed plates. A section in tension has no compressed part, so it carries its full resistance whatever its class in compression.

When does the net section govern?

Whenever there is a hole in the tension length. Equation (39) carries f_u, γ_M2 and the factor 0.9, so one bolt hole can make it decisive.

Can I print the calculation?

The full calculation is shown on screen, free and without an account. A print-ready A4 calculation note is part of the Basic plan.

Related

• Steel section in compression
• Steel section classification
• Steel tension: all sections
• SIA 263: modules and clauses

Norm: SIA 263:2013 · Page updated: 27 October 2026