Design checks

A design check turns an internal force into a verdict. The utilisation itself matters less than the combination that produced it, the clause applied, and what was substituted into the formula. Elementarium reports all four.

In this section

• 01National annexesWhere nationally determined parameters change the answer, how to select the right annex, and what to state in the report.
• 02Section classificationHow EN 1993-1-1 Table 5.2 classifies a steel section, why the class depends on the combination, and what the check does with shapes it cannot classify.
• 03Serviceability checksDeflection, drift and floor frequency checked member by member at SLS, to the national annexes, EN 1990:2023, IBC, AISC or EN 1995-1-1.
• 04Steel — AISC 360Member strength to Chapters D to H, LRFD or ASD — compression buckling, lateral-torsional buckling and every C_b option written down.
• 05Steel — EN 1993-1-1Member resistance to §6.2 and §6.3 — what is checked at every station, where buckling lengths come from, and the clauses left to you.

Two strength modules ship today, both for steel, verifying member resistance at ULS: the cross-section and the member's buckling between its restraints. Beside them are serviceability modules for deflection, drift and floor frequency at SLS. What is not checked, in any module:

• Concrete, timber and aluminium. A member in any of these materials can be modelled, meshed, loaded and solved, and the material library carries them, but no code check runs on it. Concrete to EN 1992-1-1 is the next module.
• Floor acceleration, crack widths and plate deflection. The serviceability checks cover member deflection, drift and a floor-frequency screen; slab deflection is still read off its contour — see Linear static analysis.
• Connections. No connection model, so no net-section rupture and no joint checks.

The order these arrive in is kept in one place, the release notes.

How a check reports itself

Every utilisation expands to show:

What is checked, and what is not

Checks run member by member, on solved results. They do not cover connections, foundations, detailing beyond the clauses cited, fire, fatigue, or stability of the structure as a whole. They do not choose the member for you: the check verifies the section you assigned.

Each module states its own boundary:

Anything a module does not verify is raised as a message on the check itself and carried into the report's assumptions and limitations section.

Versioned, so a check stays reproducible

A check stores which module it uses and which version of it. Re-open the project after an app release and the check resolves the exact implementation it was created with, so a number in a report issued last quarter is still the number the model produces. Upgrading to a newer module version is your decision; it never happens automatically.

When a module's scope widens, the wider one gets a new name instead of a new version, because it changes the numbers. Adding §6.3 to the EN 1993 check, or Chapter E to the AISC one, raises the utilisation of every compression member. So the member-resistance modules supersede the earlier cross-section and member-strength modules, which stay available for the checks created with them. A check on an older module offers the upgrade and waits for you to take it.

Reading utilisation sensibly