Last reviewed 16 Sept 2026 · 5 min read
Industrial buildings
Industrial buildings — factories, workshops, warehouses, hangars, power houses — need large column-free floor areas, overhead cranes, good lighting and ventilation, and quick, economical construction. Steel suits them well.
Planning considerations
- Floor area and clear height for the process and crane hook height.
- Bay width (spacing of frames along the length): commonly 6–9 m; span (across the width): 15–40 m or more.
- Lighting: north-light roofs, monitors, translucent sheets; ventilation: ridge ventilators, louvres.
- Crane type, capacity and duty; future expansion (end walls designed to be removable).
- Drainage of large roofs (gutters, downpipes), insulation, fire safety.
Structural framing systems
| System | Features | Suitable spans |
|---|---|---|
| Trusses on columns (column pinned to truss) | Knee braces or column fixity for lateral stability; simple analysis | Small–medium |
| Portal frames (rigid frames) | Columns rigidly connected to rafters; clear, unobstructed space; efficient under gravity and lateral loads; haunches at eaves | About 15–50 m |
| Pre-engineered buildings (PEB) | Tapered built-up members sized to moment demand, cold-formed Z/C purlins and girts, factory-fabricated | Wide range, fast erection |
| Lattice girders / space frames | Very long spans, hangars | 40 m and beyond |
| Arched and shell roofs | Architectural spans | Large |
Columns in crane buildings
| Column | Description |
|---|---|
| Uniform column with bracket | Light cranes; gantry girder on a bracket |
| Stepped column | Upper (roof) part narrower; lower part wider to support the gantry directly on its inner leg |
| Laced / battened column | Two legs (roof leg and crane leg) connected by lacing — economical for heavy cranes |
| Separate (twin) columns | Independent crane column tied to the building column |
Crane columns carry vertical loads, crane surge, wind and eccentric moments; effective lengths differ for the upper and lower parts and for in-plane and out-of-plane buckling.
Cladding and secondary members
- Purlins carry roof sheeting; side girts (sheeting rails) carry wall cladding and span between columns.
- Sag rods reduce purlin/girt spans in the weak direction.
- Eaves struts at the eaves carry longitudinal forces and support gutter and sheeting.
- Wind columns in gable ends reduce girt spans on end walls.