Design drawings prove that the structure works. Detailing drawings make the structure ready for fabrication, transport and assembly. We use Tekla-based detailing, bolted connection logic and DfMA thinking to reduce fabrication errors and site rework risks. A steel detail drawing is not a copy of the design drawing with more lines — it is a separate engineering deliverable, and the gap between the two is where fabrication waste and site rework are created or avoided.
Our detailing team works from your approved structural design or IFC model and takes responsibility for the whole translation: member segmentation, connection design, bolt and weld specification, piece marking, the bill of materials, and the CNC data the workshop will cut from. The output is a package a fabrication shop can work from without a second round of clarification, and a site team can erect without guessing.
DfMA is not a drawing style. It is the decision to design the structure for how it will be made, moved and assembled before any detail is drawn. In practice that means the member is segmented so it can be fabricated and coated in the shop, shipped within transport limits, lifted by the available crane, and bolted rather than welded wherever the site conditions allow. Every one of those decisions is made in the model, and every one of them shows up in the drawings as a consequence the workshop can act on.
Steel structure detailing is carried out in a coordinated Tekla 3D model rather than in 2D drawings assembled by hand. The model is checked for clashes before any sheet is plotted, so the fabrication package and the site instructions come from one consistent source. Tekla structures modeling also gives the workshop a navigable model of the whole assembly, which reduces the time a fabricator spends interpreting a flat drawing set.
Bolted modular detailing is our preferred connection strategy for overseas delivery, and the reason is specific to how your project is likely to be built. A bolted connection removes site welding, which removes the need for qualified welders on site, removes the weather dependency, and removes a large part of the tolerance risk that comes with fitting a structure together in the field. For a structure assembled far from its fabrication source, that is usually the difference between a predictable erection and an expensive one.
Bolted connection design is carried out to the governing connection standard, whether that is EN 1993-1-8, AISC 360 Chapter J, or the Chinese JGJ 82 and GB 50205 series. Bolt grade, bolt diameter, hole type and hole position tolerance, washer arrangement, pretension class and the minimum number of bolts are specified per joint rather than applied as a rule of thumb. Where the project is delivered to a market outside China, the equivalency between the bolt standards and the fabrication standard is verified so that a bolt specified in one system is not rejected on arrival against another.
Connection design is where detailing either succeeds or fails, because the connection is the point at which the calculation, the workshop and the site all meet. A connection that is correct in the model but awkward to fabricate, or that cannot be bolted on site with the equipment available, is a connection that will be changed on site. We design the connection first for buildability and erection sequence, and only then confirm it against the code limit states.
Beam-to-column connections are resolved as a family rather than case by case, so that the same detailing logic applies to every frame line in the building. The end-plate and fin-plate arrangement, the bolt gauge, the number of bolts per flange, the column flange stiffener requirement and the erection sequence are all fixed as a system. This is what allows a workshop to repeat the same detail across the whole frame, which is usually where the cost of a steel structure is actually decided.
Column base connections are designed together with the foundation interface, including the anchor bolt set-out, the grouting arrangement and the erection tolerance that the base must accommodate. Anchor rod design is checked for the forces during erection as well as the final condition, because a base that is correct in service can still be the one that causes a problem on site when the column has to be plumbed and grouted in the right order.
The drawing package is issued as a coordinated set: general arrangement drawings that define the building, shop drawings that define each piece, steel assembly drawings that define the sub-assemblies, and single part drawings that define every individual member for cutting. Steel erection drawings set out the assembly sequence, the bolt order, the crane picks and the site access required, and steel construction drawings tie the package back to the design intent so that the site team and the design team are working from the same information.
Every package is issued with buildability review notes, which record the decisions a fabricator or site team would otherwise have to raise as a query: where a piece is oversized for the available transport, where a bolted connection has been substituted for a field weld, where the coating or the marking needs to change for handling, and where the erection sequence requires a particular crane position. These notes are the cheapest part of the package to produce and the most expensive to omit.
Steel detail drawing services are delivered as one coordinated package. A drawing set that arrives in parts, or a BOM that does not match the piece marks on the drawings, pushes the reconciliation work back onto the fabricator — and the fabricator prices that work into the quotation you receive.
SJG 129-2023, GB 50205, JGJ 82, GB/T 36320, GB/T 51447, GB/T 40485 — for projects delivered under China standards, including welded and high-strength bolted connection execution.
EN 1993-1-8, AISC 360 (Chapter J), EN 1090-2, BS 5950, ISO 4032, ISO 898 — for projects delivered in the destination market, covering bolted connection design, execution of steel structures and the fastener standards the workshop will work to.
RIBA DfMA Guide, MOHURD Intelligent Construction & DfMA Specifications — the reference framework used for the manufacture, transport and assembly decisions built into the detailing.
We combine advanced analysis tools with engineering experience and code knowledge to deliver safe, efficient and buildable structural solutions. The software produces the geometry; the judgement behind the segmentation, the bolt specification and the erection sequence is what makes the structure buildable. A model can be perfect and still produce a package that no workshop wants to quote, and a fabricator who does not want to quote it will price the risk into the steel.
Send us the approved structural drawings or the IFC model, the project location, the fabrication destination and the erection sequence. We will review the buildability of the design, tell you where the detailing decisions carry the most risk, and issue a package the workshop can build from.
