This code covers the structural design, fabrication, and erection of steel tubes used in general building construction. It provides guidelines on permissible stresses, member design (tension, compression, flexure), and joint detailing (especially welded and flattened connections) for lightweight tubular structures like roof trusses and industrial sheds.
Provides guidelines for the use of steel tubes in general building construction.
Quick Reference Values
Max slenderness ratio for compression members180
Max slenderness ratio for pure tension members400
Max slenderness ratio for tension members with reversal of stress from wind/earthquake350
Minimum thickness of tubes (accessible for painting/sealed)2.0 mm
Minimum thickness of tubes (exposed to weather, unsealed)2.5 mm
Maximum deflection for flexural membersSpan / 325
Key Formulas
P = pc * A (Axial compression capacity, where pc is permissible compressive stress and A is cross-sectional area)
Practical Notes
Ends of steel tubes must be fully sealed (by welding plates, crimping, or plugging) to prevent internal corrosion, especially in exposed environments.
When flattening tube ends for bolted connections, ensure the transition is smooth and not steeper than 1 in 6 to avoid high stress concentrations.
Welded joints are highly preferred for tubular trusses to maximize structural efficiency and avoid local crushing of the tube wall from bolted connections.