The structural drawings show what a steel frame has to do. They don’t show how to build it. Steel detailing turns the engineer’s design into the documents a shop and an erection crew work from: every piece, every hole and every bolt, drawn to the sixteenth of an inch.
A complete detailing package does three jobs. It tells the shop what to cut and assemble, tells the field crew where each piece goes, and tells the purchasing side what to buy.
What a detailing package includes
Shop drawings come in two levels. Assembly drawings (sometimes called main-member drawings) show a beam, column or brace with everything welded or bolted to it in the shop: plates, clips, stiffeners, holes and welds, all dimensioned. Single-part drawings break each plate, angle and clip down on its own, which is what the laser, plasma table and saw actually cut.
Erection drawings are plans and elevations of the frame with a piece mark on every member. They show where each piece goes, which way it faces, the field bolts and welds, and the order of work where it matters. The crew reads piece marks off the steel and finds them on the erection drawings.
Anchor bolt plans (also called anchor rod setting plans) go to the concrete contractor long before any steel ships. They locate every anchor rod group with its projection, embedment and thread length, so the foundations are ready when the columns arrive. Getting these out early is one of the most useful things detailing does for a schedule.
Material lists and bolt lists sum up every shape, plate and fastener by size, grade and length. Purchasing buys from them, and they show early whether the job can run on mill lengths or needs cut-to-length stock.
CNC files let the machines skip the drawing table: DXF files for laser and plasma cutting of plate parts, and DSTV (NC1) files for beam lines that drill, saw and cope structural shapes. Clean CNC files cut errors and hours out of the shop.
On larger jobs the package can also include a 3D model, shared as an IFC file, which other trades can use for coordination.
Who designs the connections
The contract documents decide who designs the connections. Either the engineer of record shows them in the design drawings, or the design is delegated to a licensed engineer working for the fabricator. The detailer draws the connections to that design. Detailers don’t invent connection designs that no engineer has checked, so settle this question before detailing starts.
How approval works
- Kickoff. The detailer reviews the contract drawings and specifications and lists everything that is missing or conflicting.
- RFIs. Each open question goes to the design team as a request for information. Missing elevations, unclear connections and conflicts with the architectural drawings are the usual ones.
- Submittal. Shop and erection drawings go to the engineer of record and the architect, who review them for conformance with the design. Unless the contract says otherwise, the AISC Code of Standard Practice (AISC 303) sets the ground rules for this review.
- Revisions. Comments come back, the drawings are corrected and, if needed, resubmitted.
- Release for fabrication. Approved drawings are released to the shop, and the CNC files and material lists go with them.
Most delays happen at steps 2 and 3. A detailer who flags problems early and keeps RFIs specific saves weeks.
What to send for a detailing quote
- Contract drawings: structural and architectural, latest revision, with all addenda.
- Specifications: at least Division 05 12 00 (Structural Steel Framing) and 05 50 00 (Metal Fabrications).
- Connection design responsibility: shown on the drawings, or delegated to the fabricator’s engineer.
- Schedule: the date anchor bolt plans are needed, and the erection sequence if it is set.
- Model files: any IFC, DWG or Revit models from the design team.
- Shop and field preferences: bolt types, galvanizing or paint, and maximum shipping lengths.
The more complete the package, the tighter the quote and the fewer RFIs later.
Detailing and fabrication from one team
When the same team details, cuts and supplies the steel, nothing is lost between the drawings and the shop. The material lists become the purchase order, and the CNC files go straight to the laser, the plasma table and the press brake. Mona Steel prepares shop drawings, erection drawings, anchor bolt plans and CNC files from your contract drawings, and can supply and process the steel that goes with them.