Shop drawings for Australian fabricators, checked three ways before release

A full sample set for an 18 × 30 m portal frame shed: holding-down bolt plan, erection drawings, shop drawings, cold-rolled order list and NC files, in millimetres with notes to AS 4100, AS/NZS 5131 and AS/NZS 1554.1. Before release the set went through automated checks, two rounds of review by a separate AI checking agent, and a review by a structural engineer of my team. This page shows what the checks found.

Steel detailing · AS 4100 · AS/NZS 5131 · sample set

37 sheets6 general arrangement drawings and 31 shop drawings, plus 7 lists

17.9 t421 assemblies: portal frames, end walls with a door frame, purlins, girts and bracing

1300 boltsedge distance and spacing checked against AS 4100, 0 below minimum

3 checksautomated gate, an AI checking agent in two rounds (1 critical and 14 major findings, then 9 fixes), engineer review

The sheets

Hot-rolled frames in 300PLUS with grade 250 plate, cold-rolled Z and C sections in G450 with bridging, M20 8.8/TB at the knees and apex, M16 8.8/S bracing, M12 4.6/S purlin and girt bolts. Member sizes in this sample are illustrative; on a real job they come from the engineer’s design drawings.

Holding-down bolt plan with grid dimensions, base plate details A to E and a holding-down bolt schedule — Holding-down bolt plan: every base located on the grid, base plate details with hole spacing, and a schedule the concreter can set out from (rod size, length, embedment, plate washer, grout). The wind column and door jamb details are dimensioned from the grid line, because neither sits on it.

Shop drawing of a 360UB rafter with end plates, purlin cleats, bracing cleats and sections — Rafter R/2: end plates for the knee and apex, purlin cleats at 1380 centres with running dimensions, bracing cleats located on the top view, and the grid locations of both pieces in the corner table.

Shop drawing of a 360UB column with base plate, haunch, girt cleats and sections — Column C/3: base plate with 30 mm holes for M24 holding-down bolts, girt cleats and the knee end plate, each located by a dimension.

Purlin detail sheet for a Z200 purlin with hole positions and a material list — Purlin and girt sheets: hole positions from one end with running dimensions, in the format of a cold-rolled supplier’s detail sheet. The same pieces go to the supplier as an order list.

End wall elevation with wind columns, door frame, girts, bridging and piece marks — End wall elevation: wind columns, a 4.0 × 4.5 m door frame, girts and bridging, one mark for each piece type on the wall.

Roof marking plan with grid lines, rafters, purlins, roof bracing and bridging marks — Roof marking plan: rafters, purlins, roof bracing in the end bays and bridging, with the erection notes on the sheet.

The checking gate

The 3D fabrication model, the sheets and the NC files are checked before the set is released. An error stops the set; it is fixed in the model or in the sheet generator, and everything is regenerated, never patched by hand.

Check	Basis	This set
Bolt edge distance and spacing, every hole in every connected part	AS 4100 minimums	1300 bolts, 0 below
Hole sizes on the sheets, in the notes and in the NC files agree	sheet ↔ NC comparison	18 mm for M12, consistent
Clashes between members	3D model	0
Every NC part present once	NC (DSTV) files ↔ model	678 parts, 0 missing, 0 duplicate
Marks numbered from 1 with no gaps; left- and right-hand pieces kept as separate marks	model numbering	pass
Holding-down bolt schedule matches the model	rod length, embedment, washer, grout	pass
Supplier list totals match the assembly list	cold-rolled list ↔ assembly list	pass

What the reviews caught

Passing the automated gate is not enough. A separate AI checking agent, with no part in producing the set, reads the sheets the way a fabricator and an erector would and compares them with the model data. A structural engineer of my team then reviews the set before it is released. These are real findings from the two checking rounds on this sample.

Round 1

Five bases with no mark

The holding-down bolt plan template left 5 of 20 base locations unmarked, including a wind column and both door jambs. All 20 are now marked and match the elevations.

Round 1

Hole note contradicted the holes

A sheet note said 18 × 22 slotted holes; the model and the NC files drilled 18 mm round. The note now matches what the machine will drill.

Round 1

Wind column top connection

The intent is a slotted connection so the rafter can deflect without loading the wind column; the model had round holes. The sheets now carry a HOLD note until the engineer confirms the slot.

Round 2

Wind column bolts 40.5 mm off the grid

The wind column bases sit 40.5 mm inside the grid line and the door jambs 10.5 mm outside, but the base plate details had no grid reference. A concreter setting the bolts on the grid would have missed by 40 mm. The details now show the grid and both offsets.

The package

Everything a fabricator needs to price, order and start cutting, with consistent file names and a drawing register.

General arrangement: holding-down bolt plan, roof marking plan, side and end elevations
Shop drawings for every assembly, with grid locations and a material list on each sheet
Lists: assembly, assembly part, part, bolt summary, bolt erection, bridging and drawing lists
Cold-rolled order list (CSV) for the purlin and girt supplier
NC (DSTV) files for plates and members, and DWG or IFC on request

Drawing set, 37 sheets (PDF) Full sample package (sheets + lists, zip)

✔ ENGINEER REVIEWED · 1 Nov 2026

Sample project for demonstration only; not for construction. Section sizes are illustrative and not designed.

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