Many buyers think of a steel building as a product that is simply ordered and delivered. In reality, every building passes through a defined engineering chain before the first plate is cut. Knowing that chain - and what happens at each step - helps you ask the right questions, set realistic expectations, and judge whether a supplier is doing proper engineering or just quoting a catalogue.
Stage 1: Requirements and Site Data
The process starts with the information that defines the building: length, width, eave height, roof slope, intended use, and the site location. The location matters because wind, snow, seismic, and temperature values all come from the local code or national annex. A quotation issued before these inputs are known is only an estimate.
Stage 2: Preliminary Sizing and Quotation
The engineer selects a structural system (typically a portal frame for 12–36 m spans), sizes the main members with software such as PKPM or Tekla, and calculates tonnage. The quotation is then built from steel tonnage, section complexity, surface treatment, cladding, packing, and freight. Expect this stage to take a few working days for a standard building.
Stage 3: Structural Design and General Arrangement Drawings
After the order, the full structural design is produced: frame analysis, member design, connection design, and general arrangement drawings showing every frame, bay, and brace. The design follows the applicable standard - for Chinese-made buildings, typically GB 50017 and GB 50009, with GB 50011 for seismic regions; for European projects, EN 1090 and the Eurocodes.
Stage 4: Detailing and Shop Drawings
The detailer converts the design into piece-by-piece fabrication drawings - every plate, bolt, weld, hole, and cutting length - plus erection drawings and marking plans. This is the stage where the building becomes "buildable."
What the Buyer Should Expect and Provide
Site location and building use at the very first inquiry.
Approval of the general arrangement drawings before fabrication starts.
A clear design basis: which code, which wind/snow values, which safety level.
A schedule: design, drawing approval, fabrication, inspection, shipment.
The design process is where quality, safety, and cost are locked in. A supplier that walks you through each stage transparently is engineering your building; one that only quotes a price is guessing. Ask for the design schedule and the drawing approval points before you commit.