Prefabricated steel workshops — crane bay, or clear span and no crane

By Johnny, export engineer at Hebei Hongji Shunda Steel Structure Engineering Co., Ltd.

Crane bay or clear span

A crane bay is a frame line with a rail on it. The rail level, the crane capacity and the hook approach together set the column size and the eave height, and the building is effectively designed around the crane rather than around the floor.

Clear span with no crane is a different structure, not a cheaper version of the same one. Removing the crane removes the fatigue detail, the rail bracket and the runway beam, and it allows a lighter frame — which is exactly why a workshop should say which case it is on the enquiry.

All five buildings on this site are crane-free. The 150 t overhead cranes in our own production base are the ones that build the product, not the ones the product is designed to carry.

Eave height and bay spacing

Eave height is set by the tallest thing that has to move inside, which is rarely the tallest thing installed. Maintenance access, a lifted part, a mezzanine or a truck are what actually drive it.

Bay spacing is a trade: larger bays mean fewer frames and heavier ones, smaller bays mean more frames and lighter ones. There is a band where the total steel is close to flat, and outside that band it climbs. On the five delivered buildings the spacing is 6 m or 7 m, and on the 98 m building that divides the length into exactly 14 bays.

Erection is a design output

The erection sequence should be decided in the drawing set, not on site. Which frames are braced first, where the temporary stability comes from and what order the roof goes on are all design decisions, and a set that does not answer them gets answered by whoever is standing there.

Transport is the other constraint. A modular approach ships assembled panels and needs less site labour; a stick-built approach ships loose members and needs fewer heavy lifts. The decision depends on the road between the factory and the site more than on the steel.

Delivered record

Two food factory workshops in Brazil at 100 m and 40 m spans, 7 m bay spacing, 13,000 m² between them; one 40 m × 50 m logistics warehouse at 6 m bays and two waste treatment plants in Burkina Faso. Five buildings, 19,800 m², none with an overhead crane. Spans, lengths and areas in one table.

Production side: 125,000 m² across six workshops, four 150 t overhead cranes in the West Zone from 2026, ISO 9001 certificate 19822QA0131R1S valid to January 2028.

Numbers behind this page

Production base 125,000 m² across six workshops; overhead cranes four at 150 t each in the West Zone from 2026; factory established 2000, current company name since 2014, exporting since 2004; quality management ISO 9001 — certificate 19822QA0131R1S, valid to January 2028. Certificate and inspection records.

Delivered spans so far 30 m to 100 m at 6 m or 7 m bay spacing, five buildings totalling 19,800 m² in Brazil and Burkina Faso. The full record, in numbers.

Notes on this sector

• Workshop crane bay: the rail level comes first
• Clear span without internal columns
• Eave height: what actually sets it
• Bay spacing is a trade, not a preference
• Erection sequence is a design output
• Modular or stick-built: the transport envelope decides

Next step

Send the process inside the building and the loads it has to carry — span, length, eave height, crane duty or none, and the roof and wall spec you are working to. Sizing comes back as a drawing question, not a price. Send a project description.