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International & multi-code steel design
The same Studio model can be checked to the US, European, Thai and Australian-bridge steel codes, not just AS 4100 - pick a region once and the member checks follow it.
This page is the international companion to the local AS 4100 design checks. The maths is the same idea (turn the analysis into a pass/fail per member), only the standard changes.
The codes you can pick
| Code (as labelled in Studio) | Region it leads | What runs under the hood |
|---|---|---|
| AISC 360 (US) | United States, Canada | AISC 360 (LRFD) steel engine |
| EIT 1015-57 (Thailand) | Thailand | The AISC 360 engine, labelled and clause-noted as EIT (Thailand adopts AISC 360 LRFD) |
| Eurocode 3 (EU) | Europe, United Kingdom | Eurocode 3 (EN 1993-1-1) steel engine |
| AS 5100.6 (bridge) | (chosen by hand) | The validated AS 4100 steel engine - AS 5100.6 bridge steel design follows the same clauses |
Plain English
- LTB (lateral-torsional buckling) - a long, unrestrained beam can twist and buckle sideways before it reaches its full bending strength. All four codes reduce the bending capacity for this.
- Le (effective length) - how far the member can buckle between restraints. Longer Le = lower capacity.
- Cb (AISC/EIT moment factor) - credit for a non-uniform bending shape along the member. 1.0 is the safe, uniform-moment default.
How to choose your design code (the region)
You normally never pick the code member by member - you set a design region and every steel check uses it.
- Set the global default. Open Settings (gear icon) and choose Design region (default): Australia, New Zealand, United States, Europe, United Kingdom, Canada or Thailand. This persists across sessions.
- (Optional) Override for one project. In the PDF report title block, set the Design region field. It rides on the model, so the same job designs to the same code on any machine and for any colleague (export / import / autosave all carry it). Leave it on "use global default" to inherit the Settings value.
- Resolution order: project override -> global default -> Australia.
When the region's steel code is international (US/Canada -> AISC 360, Europe/UK -> Eurocode 3, Thailand -> EIT), the International steel check panel becomes the lead check, opens automatically when you select a member, and the whole-model Design tab runs that code instead of AS 4100. Australia/NZ keep AS 4100 first. The region also points the section library at that country's catalogue by default, so a US job opens on US sections.
Canada borrows the US engine
Canada has no CSA S16 engine here - it runs the AISC 360 engine and is labelled "AISC 360 (Canada - CSA S16 not yet modelled)" so the report never implies CSA S16 was run.
How to check one member
- Assign a real section. Open the member's inspector and use Browse sections to pick a catalogue section. The check needs section geometry (depth, flange, web, Zx/Sx), so a bare or non-catalogue section cannot be checked.
- Solve (
S) so the analysis demands exist. - Select the member. In the inspector, open Connection & material checks (optional) and find International steel check (AISC 360 / EIT / EC3 / AS 5100). If your region is international it is already open and leading.
- Confirm the code and inputs (below), then read the result bars.
Panel inputs
| Input | What it is |
|---|---|
| Design code | AISC 360 / EIT / Eurocode 3 / AS 5100.6. Defaults to the region's code; changing it by hand always wins. |
| Effective length Le (m) | Defaults to the member length. Edit it down if the member is restrained between its ends. |
| Cb (moment factor) | AISC 360 / EIT only. Defaults to 1.0 (conservative). |
| N* compression (kN) | Axial demand, pre-filled from the analysis. |
| M*x major (kN·m) | Major-axis moment, from the analysis. |
| M*y minor (kN·m) | Minor-axis moment, from the analysis. |
| V* (kN) | Shear demand, from the analysis. |
The section properties and the demands come straight from the model; you only ever tune Le (and Cb for AISC/EIT) for restraints the analysis does not know about.
What each code checks
Every code reports the same four actions plus a combined check and the section class. The labels differ because each standard names things its own way.
AISC 360 (US) and EIT 1015-57 (Thailand) - same engine, EIT just relabelled:
| Result row | Meaning |
|---|---|
| Axial N*/φN | Compression utilisation (Chapter E flexural buckling) |
| Major M*x/φMnx | Major-axis bending with LTB (Chapter F2) |
| Minor M*y/φMny | Minor-axis bending (Chapter F6) |
| Shear V*/φVn | Shear |
| Combined | Chapter H combined axial + bending interaction, with the governing equation |
| φPn(c) / φMnx / φMny | The compression and bending capacities behind the ratios |
| Section class | Compact / non-compact / slender (Table B4.1b) |
Eurocode 3 (EU/UK):
| Result row | Meaning |
|---|---|
| Axial N*/φN | Compression resistance (Nc,Rd) |
| Major M*y/Mb,Rd | Major-axis bending with LTB (Mb,Rd) |
| Minor M*z/Mz,Rd | Minor-axis bending |
| Shear V*/Vpl,Rd | Plastic shear resistance |
| Combined | The Cl 6.3.3 interaction, with the governing equation |
| Nc,Rd / My,Rd / Mb,Rd | The resistances behind the ratios |
| Section class | EC3 Class 1-4 |
EC3 axis naming
Eurocode 3 calls the strong axis y-y and the weak axis z-z, the opposite of the Australian convention. Studio maps your major moment to My and your minor moment to Mz so the numbers line up - the row labels just read the EC3 way.
AS 5100.6 (bridge) runs the validated AS 4100 steel engine (AS 5100.6 Cl 6 steel design follows the AS 4100 clauses), reported in the AISC-style row layout (φMnx/φMny). Pick it by hand from the Design code dropdown when you are designing a bridge member.
A green bar (utilisation ≤ 1) means OK; red (> 1) means OVER. The Combined line is the one that governs the member.
Show working (clause by clause)
Open Show working under the result and Studio expands a typeset, clause-referenced derivation in the engineer's own code - the same trust feature as the AS 4100 Design tab:
- AISC / EIT shows AISC 360-16 references (e.g. Table B4.1b classification, Ch E3 compression, Ch F2/F6 flexure, Chapter H combined).
- Eurocode 3 shows EN 1993-1-1:2005 clause references.
Every line carries the standard and edition, and the values come straight from the validated solver core (through the WASM boundary) - nothing is re-derived for display, so each line traces back to the standard. Use the copy button to paste the working into your own calc sheet.
How it appears in the PDF report
When the region is international, the PDF report automatically:
- titles the design section with the active code, e.g. "Steel design check (AISC 360)" or "(Eurocode 3)",
- lists every member with its class, utilisation, status and governing action, and
- includes the clause-by-clause working for the governing member in that code.
Set the report's Design region field to lock the whole report to one code regardless of the machine it is opened on.
Auto-size and the whole model
The international engines also drive the rest of Studio:
- The Design tab in the results panel runs the region's code across every member at once (see design checks for the table controls - failures-only, group-by-section, governing case).
- Auto-size optimises sections against the active international code, not just AS 4100.
For concrete and other calculators see concrete design, the stand-alone calculators and the load generators.
Scope & assumptions (read before professional use)
This is an honest first-pass slice - useful for sizing and comparison, not a substitute for a full design to the standard:
- Effective length defaults to the member length, with no intermediate restraints modelled. Set Le per member in the inspector if it is restrained between its ends, or φMb/φNc will be conservative.
- Cb = 1.0 (uniform moment) by default for AISC/EIT - edit it for a non-uniform shape.
- Canada runs the AISC 360 engine (CSA S16 is not modelled) and says so.
- EIT runs the AISC 360 engine and is labelled/clause-noted as EIT.
- Members that are cold-formed, non-catalogue or missing geometry are listed as not checked rather than silently passed.
Verify before professional use
Confirm restraints, effective lengths, section data, steel grade and the governing load combination against the relevant standard and a manufacturer catalogue before relying on these numbers.