Structural steel detailing is the work of turning an approved structural design into the information a fabricator needs to cut, drill, weld, mark and assemble each steel piece, and the information an erector needs to put those pieces together on site. The detailer models or draws every member, plate, bolt and weld shown or implied by the design, then issues shop drawings, erection drawings, schedules and, where agreed, digital fabrication data.
Detailing sits between engineering design and fabrication. It does not replace either of them.
What does a steel detailer produce?
The exact package depends on the contract, but most steel detailing scopes draw from the deliverables below.
| Deliverable | What it shows | Main user |
|---|---|---|
| Detailing model (e.g. Tekla Structures) | Every part, bolt and weld in 3D, numbered and grouped into assemblies | Detailer, checker, coordinator |
| Assembly (shop) drawings | One shipping piece: main member plus fittings, dimensions, welds, holes | Fabrication shop |
| Single-part drawings | One plate or profile with cutting and hole information | Cutting/drilling, plate shop |
| Erection drawings / erection GA | Where each marked piece goes, with bolt and level information | Erection team, site |
| Anchor bolt / embedment plans | Location of items cast into concrete to receive steel | Civil contractor |
| Bolt lists, member lists, MTO | Quantities for ordering and tracking | Procurement, estimating |
| NC/CNC files (e.g. DSTV) | Machine data for profiles and plates, where requested | CNC equipment |
The AISC Code of Standard Practice (ANSI/AISC 303-22) defines shop drawings narrowly, as "drawings of the individual structural steel shipping pieces that are to be produced in the fabrication shop". That definition is useful because it separates piece-level fabrication information from the overall arrangement shown on design drawings.
Is steel detailing the same as structural design?
Detailing is not structural design. The structural engineer, often called the engineer of record or, in AISC terminology, the owner's designated representative for design, decides member sizes, loads, connection forces and code compliance. The detailer represents that design accurately and buildably.
Two points cause the most confusion:
- Connections. On some projects every connection is fully designed by the engineer. On others an experienced detailer may select or complete connections from tables or design criteria that the engineer has specified. On others still, connection design is delegated to a licensed engineer working for the fabricator. AISC 303-22 requires the design team to state which approach applies. European and UK projects handle this through the execution specification and contract. Never assume. Write it into the scope.
- Approval. When the engineer reviews shop drawings, they are checking conformance with design intent. That review does not usually transfer responsibility for the dimensional accuracy of the detailing. The split is set by the contract and the governing standard, so confirm it for each project.
At PetroHill, our standard offer is modelling, drafting and detailing using engineering information from the responsible design team. Connection engineering, calculations and certification are not included unless they are separately agreed with appropriately authorised professionals. Our responsibility matrix sets out the boundary.
How a detailing package moves from inputs to issue
- 1Input review. The detailer reads the design drawings, specifications, connection criteria, vendor data and interface drawings, and lists gaps.
- 2Queries (RFIs). Missing dimensions, unclear connections and clashes are raised in writing before they become assumptions.
- 3Modelling. Grids, levels, members, then connections and fittings are modelled to the agreed level of detail.
- 4Numbering and drawing production. Identical pieces get the same mark. Assembly, single-part and erection drawings are generated and dressed to the project drawing standard.
- 5Internal checking. The drawings are checked against the inputs before issue, by a checker other than the modeller where the agreed checking arrangement includes one.
- 6Issue for review. Drawings go to the client or engineer with a transmittal and drawing register.
- 7Comment incorporation and re-issue. Consolidated comments are resolved, revision clouds and letters applied, and superseded sheets identified.
- 8Issue for fabrication. Released drawings, reports and NC data are handed over in native and PDF formats.
Where detailing fits on energy and industrial projects
On oil and gas, petrochemical and power projects, steel packages are often repetitive but interface-heavy. Pipe racks, equipment platforms, access stairs, skid steel and pipe supports all depend on piping loads, vendor equipment, foundations and cable tray routes that may still be changing. Good detailing there depends less on drawing speed and more on controlling inputs and revisions, so that a late piping change does not leave the shop fabricating superseded steel.
What to check before you commission detailing
- Is the design issued for construction, or at least frozen for the areas being detailed?
- Is connection responsibility stated for each connection type? (See who is responsible for connections.)
- Are the governing standard, steel grades, bolt grades and coating system specified?
- Is the drawing standard (title block, numbering, marking) agreed?
- Are software, version and exchange formats confirmed?
- Is the review cycle (who comments, how fast, in what format) defined?
If any answer is "not yet", detailing can usually still start on the frozen areas, provided the open items are logged as assumptions.
Frequently asked questions
Is a steel detailer an engineer?
Not necessarily. Many detailers are experienced technicians. Detailing requires strong knowledge of fabrication and standards, but design responsibility stays with the engineer unless the contract assigns it otherwise.
Does detailing include connection design?
Only if the contract says so. The design team should state for each connection whether it is fully designed, to be selected by an experienced detailer from stated criteria, or delegated to a licensed engineer.
What software is used for steel detailing?
Tekla Structures is widely used for industrial steel. Advance Steel, SDS2 and AutoCAD-based workflows are also common. The right choice is whichever your project and fabricator have agreed.
Next step
If you have an approved structural design and need fabrication drawings, see our structural steel detailing and fabrication documentation service, or send your drawings and scope for review. We will identify input gaps and confirm the deliverables before quoting.
Related services
References
Technical sources consulted. Standards are paid documents; confirm clauses against the licensed edition named in your project specification.
- ANSI/AISC 303-22 Code of Standard Practice · AISC (copy hosted by SSI) (opens in a new tab)
- Structural Steel Detailing Practices—Good and Bad · AISC Engineering Journal (opens in a new tab)
- Drawings in Tekla Structures · Trimble (opens in a new tab)
