steel-structure-drawing-review
Steel Structure Drawing Review: Shop Drawing Checklist & Pro Tips
A structural engineer at a drafting desk reviewing large-format steel shop drawings, with a tablet showing a Tekla 3D connection model, a scale ruler, red/blue pencils, and a coffee cup, in an industrial design office.
The single most expensive mistake in a steel project is not caught on the shop floor—it is caught on paper, before a single beam is cut. That is what a steel structure drawing review is for: checking the detailer's drawings against the engineer's design, the site conditions, and the connection logic. A shop drawing approved in a hurry becomes a container of wrong holes, mismatched elevations, and missing members on site—often discovered after shipping, when fixing costs ten times more.
This article walks through who reviews what, exactly what to check on shop drawings, connection details, and the material takeoff, how to run an efficient RFI process, and the most common drawing mistakes that cost money. For checking the actual fabricated steel after it is made, see our steel structure quality inspection guide. This article is about reviewing the drawings before fabrication starts.
Who Reviews What in a Steel Project
A steel structure drawing review does not happen in one pass by one person. Three drawing types move through three sets of hands, and skipping any layer is how errors survive to the field.
Design drawings (general arrangement, GA). The structural engineer produces these. They fix loads, member sections, grid lines, elevations, and overall geometry. They are the contractual design intent; they are not detailed enough to cut from.
Shop drawings (fabrication drawings). The detailing company or factory produces these. Every beam, column, brace, connection plate, bolt hole, and weld bevel is broken out with its mark, length, hole gauge, and finish. These tell the factory how to actually cut, weld, drill, and paint each member.
Erection drawings. These tell the site crew the assembly sequence, member marks, lifting points, and temporary bracing positions. They do not drive fabrication but they drive site safety and sequence.
The approval flow is defined by industry practice such as the AISC Code of Standard Practice: the detailer submits the shop drawing set to the design engineer as an RFA (Request for Approval). The engineer returns it approved, approved-as-noted, or rejected. No cutting begins until approval. For imported projects, the buyer's local structural engineer must also review and stamp the drawings for local-code compliance (AISC, Eurocode, or AS/NZS, depending on destination). Overseas factories typically detail to Chinese national codes, and bolt spacings, weld details, and load combinations can differ from Western codes—that gap is exactly why the local review matters. The drawings above are only one half of the design intent; the other half is the written performance and workmanship document that calls out steel grades, weld classes, coating systems, and tolerances—see our steel structure technical specification guide on what sections belong in a spec book and how it pairs with the drawing set.
Table 1: Drawing Types & Review Responsibility
| Drawing Type | Prepared By | Reviewed By | Key Check |
|---|---|---|---|
| Design / GA drawings | Structural engineer | Owner / local authority | Loads, sections, grid, elevations |
| Shop / fabrication drawings | Detailer / factory | Design engineer (RFA) | Dimensions, holes, welds, material grade |
| Erection drawings | Detailer / factory | Site foreman / engineer | Assembly sequence, marks, lifting points |
| Connection details | Detailer | Design engineer | Bolt size, weld size, stiffeners |
| Material takeoff / BOM | Detailer | Procurement / estimator | Weights, missing items, surface area |
A typical export project also benefits from an independent steel building third-party inspection at key milestones, but inspection starts from approved drawings. The drawing-review layer is one part of a wider bid-assessment process: before any drawings are even produced, an owner running a competitive tender scores each supplier's proposed design, shop-drawing capability, and QC history under a structured steel structure technical bid evaluation that ranks bidders on both engineering depth and commercial terms. Before that shortlist is even formed, the same bidders should clear a basic steel supplier due diligence screen—company registration, financial health, and export track record—so that drawing review is only spent on factories that will still exist when the first beam ships.
Reviewing Shop Drawings
A steel structure shop drawing review is where most of the hours are spent. This is the heart of a proper steel structure drawing review process. Work systematically, or you will miss the one error that matters.
General conformity. First, confirm the drawing set matches the design: grid spacing, column locations, footprint, eave height, ridge height, and bay spacing. Member marks must be unique, with no duplicates and no gaps against the member schedule. Every H-section, built-up beam, plate thickness, and tube must match the structural calculation notes.
Dimensions and shipping limits. Check overall member length, end distances, hole spacings, and splice locations. A standard 40HQ container accepts members up to roughly 12 m (39 ft), so any longer member must be split into a shipping piece with a reachable field splice. Camber annotations on long roof beams must match the deflection calculation; missing camber makes a roof look saggy even when structurally fine.
Material and surface finish. Confirm the grade on every sheet matches the design—Q235B / Q355B (GB) or ASTM A36 / A572 Gr.50 (US). Check surface preparation and coating: blast to ISO 8501-1 Sa2.5, primer and topcoat number of coats, and dry film thickness (DFT, e.g., ≥80 μm total). If galvanizing is specified, confirm it appears in the BOM and notes.
Table 2: Shop Drawing Review Checklist
| Item | What to Check | Common Error |
|---|---|---|
| Grid & elevations | Match GA drawings | Wrong eave height by one bay |
| Member marks | Unique, complete, cross-referenced | Duplicate mark ships wrong piece |
| Sections & plate thickness | Match calculation notes | Thinner web than designed |
| Member length & splices | ≤12 m (39 ft) shipping; splice detailed | Long member cannot fit container |
| Camber | Matches deflection calc | No camber on long-span beam |
| Material grade | Q235B / Q355B or A36 / A572 Gr.50 | Grade swapped in notes only |
| Surface treatment | Sa2.5 blast, primer/topcoat, DFT | Missing primer on underside |
| Anchor-bolt layout | Matches foundation drawings | Bolt positions off by 50 mm |
Connection Detail Drawings
Connection details are the highest-risk sheets in any steel structure drawing review. A slightly short beam can be shimmed; a connection with the wrong bolt direction cannot be assembled at all.
Review every beam-column, beam-beam splice, column base, bracket, and brace connection. Check bolt hole diameter, count, and grade (e.g., 10.9 / A325), weld size and length (fillet leg, full-penetration notation), stiffener presence, and connection plate thickness. Bolt spacing, edge distance, and gage must satisfy the governing code.
The most common connection errors are predictable: - Bolt holes drilled for a shop-fit direction that conflicts with field access—bolts cannot be driven from the side they need to go. - Connection plate or stiffener physically collides with the beam/column flange when assembled. - Weld notation contradicts how the shop can actually weld (e.g., a both-sides fillet where one side is unreachable). - Column-base anchor-bolt layout does not match the foundation plan.
Modern detailing makes this easier. A 3D BIM model with clash detection catches most geometry conflicts before the drawing is even printed. Our own detailing workflow uses Tekla for every export order; see steel building BIM digital fabrication for how the model drives CNC files. For the trade-offs between bolted and welded joints, read bolted vs welded steel connection.
Material Takeoff & Bill of Materials
The steel structure material takeoff (BOM) is where review becomes money. The BOM is the bridge between the drawing set and the invoice, the packing list, and the ocean freight.
Check that total weight per member category (columns, roof beams, roof bracing, wall girts, purlins, base plates) reconciles with the design estimate within a few percent. Connection plates, stiffeners, bolts, shear studs, and weld consumables must be listed separately—not buried in a lump sum. Surface area for painting and fireproofing should be stated so coating quantities are not guessed.
Why this matters in three ways: 1. Weight drives price. The FOB quote and ocean freight are both weight-based; a BOM that understates weight hides a cost problem. 2. Missing items are expensive to fix. Knee braces, tie rods, sag rods, and flange bracing are classic omissions. A missing brace set at erection requires a separate LCL shipment. 3. Substitution changes weight. If a grade or section is swapped during procurement, the BOM must be updated—see steel material substitution for how recalculation works. For steel weight and cost per area, see steel building cost per square meter.
Table 3: Material Takeoff Checklist
| Item | Unit | Check Against | Notes |
|---|---|---|---|
| Main frame (columns, rafters) | tonnes (t) / kg | Design estimate | Reconcile ±5% |
| Purlins & girts | tonnes (t) / kg | Schedule | Include C/Z lengths |
| Bracing & tie rods | pieces | Drawing set | Count knee braces |
| Bolts (HSFG, ordinary) | sets / boxes | Spec | Grade 10.9 / A325 |
| Base plates & anchors | sets | Foundation plan | Anchor bolt length |
| Paint / fireproofing area | m² / ft² | BOM | DFT target noted |
| Galvanizing weight | tonnes (t) | Spec | Include if specified |
Need a Second Pair of Eyes on Your Shop Drawings?
We detail every export order in Tekla and submit a full RFA package—GA, shop, connection, and erection drawings plus a complete BOM—so your local engineer can approve once and fabrication starts without surprises. Ask for a sample drawing set.
Request a Sample Shop Drawing Package →
The RFI Process
An RFI (Request for Information) is a written question raised during drawing review: the drawings are unclear, contradictory, or incomplete, and the reviewer needs the design engineer to clarify before cutting. RFIs are a routine output of every steel structure drawing review. RFIs are logged on a form that carries the sheet number, member mark, the exact question, and (helpfully) a proposed answer the engineer can accept or correct.
The most efficient RFI discipline is to batch. Gather every issue across the whole drawing set, then send one consolidated RFI pack—not five separate emails over three weeks. Each round trip costs time; a consolidated pack turns a two-week ping-pong into a five-day resolution. Require written replies by email or formal addendum; a verbal answer in a site meeting is not a decision, it is a future dispute.
It is important not to confuse an RFI with a change order. An RFI resolves ambiguity in the existing design; a change order changes the design itself. If the engineer's RFI reply alters a section, a location, or a load, that becomes a formal variation—see steel building change order management for how that process works. For how samples and physical mock-ups tie into drawing approval, see steel building sample confirmation.
Common Drawing Mistakes That Cost Money
After decades of export projects, a short list of drawing errors recurs far more often than it should.
Table 4: Top Drawing Mistakes & Impact
| Mistake | When Found | Typical Cost Impact | Prevention |
|---|---|---|---|
| Anchor-bolt layout vs foundation mismatch | At erection | Rebore or re-pour footing; 1–4 weeks | Cross-check with foundation drawings pre-RFA |
| Member mark mismatch | At unloading | Wrong members shipped; re-send | Marking audit before packing |
| Missing knee braces / tie rods | At erection | LCL shipment, crew idle | BOM completeness check |
| Coating spec wrong for environment | At inspection | Repaint or galvanize on arrival | Match corrosion category in review |
| Member over 12 m (39 ft) unspliced | At loading | Cannot load standard container | Shipping-length check per piece |
| Bolt direction conflicts with field access | At bolting | Torch slot or rework | 3D clash check |
The fixes are simple but require discipline: use a written checklist (Table 2), review every connection 100% rather than spot-checking, request the BIM model alongside the PDFs, and confirm anchor-bolt locations against the foundation drawings before the concrete is poured. A pre-shipment steel building inspection checklist catches what the drawing review missed, and a steel factory audit checklist confirms the detailer will not repeat it.
Drawing-review mistakes are often symptoms of deeper structural-design errors. Our common steel structure design errors guide catalogs the most frequent mistakes—load combination omissions, prying-action oversight, bracing layout asymmetry, and base-plate thickness under-design—and how to catch them before shop drawings are issued.
A real example: a 24 m × 48 m (79 ft × 157 ft) workshop exported to Australia. The local engineer flagged three issues in the RFA package—an anchor-bolt layout conflict with the foundation, a missing knee-brace set, and two roof rafters over the 12 m (39 ft) container limit. All three were resolved by batched RFI within five working days, before any steel was cut. Had they slipped through, the rework shipment would have cost several times the review time.
Conclusion
A steel structure drawing review is the last gate before steel is cut. Spend days reviewing now to save weeks of rework and thousands in freight later. Focus on connection details, BOM completeness, and anchor-bolt positions against the foundation, and raise every question in one written, batched RFI pack. Approved drawings are the cheapest insurance a steel project can buy.
Get Drawings Your Engineer Can Approve in One Pass.
Our detailing team issues a complete RFA package—GA, shop, connection, and erection drawings plus a full BOM—so review cycles stay short and fabrication starts on time. We work to your local code (AISC, Eurocode, or AS/NZS).
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Reference Links
- AISC 360 Specification for Structural Steel Buildings
- ASCE 7 Minimum Design Loads and Associated Criteria for Buildings and Other Structures
- ISO 12944 Corrosion protection of steel structures by protective paint systems
About the Author
Senior Structural Engineer
With over 20 years of hands-on experience in steel structure design and prefabricated building engineering, our in-house senior structural engineer has personally contributed to more than 500 steel building projects—including warehouses, industrial factories, aircraft hangars, agricultural buildings, and commercial structures. The focus is on translating design codes such as AISC 360, ASCE 7, and Eurocode 3 into buildable, cost-effective steel solutions that balance structural performance, fabrication efficiency, and total project cost.
Learn more about our engineering team
FAQ
Q1: What should I check when reviewing steel shop drawings? A: Check five areas: (1) grid lines, elevations, and sections match the design drawings; (2) member lengths and splice locations fit shipping (≤12 m / 39 ft per container); (3) connection details—bolt sizes, weld sizes, stiffeners—are buildable and match loads; (4) material grades and surface treatment (e.g., Sa2.5 blast, primer) match specs; (5) the material takeoff/BOM is complete, with no missing knee braces or ties.
Q2: What is the difference between shop drawings and erection drawings? A: Shop (fabrication) drawings tell the factory how to cut, weld, and paint every member—dimensions, hole locations, weld sizes. Erection drawings tell the site crew how to assemble the frame—sequence, member marks, lifting points, and temporary bracing. Both must be reviewed, but they answer different questions.
Q3: How does the shop drawing approval process work? A: The detailer submits shop drawings to the structural engineer as an RFA (Request for Approval). The engineer reviews and returns them approved, approved-as-noted, or rejected. No cutting begins until approval. For imported projects, the buyer's local engineer must also stamp them for local code compliance.
Q4: What is an RFI in steel construction? A: An RFI (Request for Information) is a written question raised during drawing review—when drawings are unclear, contradictory, or incomplete. It is logged with the sheet number, member mark, and a proposed answer. RFIs should be batched and answered in writing so nothing is decided verbally and lost.
Q5: Why do imported steel drawings need extra review? A: Overseas factories detail to their own national code (e.g., GB in China). Bolt spacings, weld details, and load combinations may differ from AISC, Eurocode, or AS/NZS. A local structural engineer must review and stamp the drawings before fabrication so the structure meets your building code and passes permit inspection.
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