CLOSED STEEL FRAMED WIND TRUSSED ROOF TYPE STRUCTURES

Industrial buildings whose height exceeds about 7 metres suffer the disadvantage of excessive side sway inside wind loads unless oversized columns and rafters are incorporated in the engineering design of the portal frames. In these circumstances it is more cost effective to use horizontal roof bracing designed to transfer sway forces to the rigid outer corners of the building resulting in a considerable reduction of column size together with an appropriate increase in rafter size.

The skillion roofed building lends itself best to this method of construction but in some case a gabled roof with a flat pitch can perform equally well. In the case of a gabled trussed roof the horizontal bracing should be located in the plane of the bottom chords of the trusses.