built-up beam[′bilt‚əp ′bēm]
an element of framed structures consisting of individual angle irons, channels, I-beams, and similar simple metal sections joined into a single unit by batten plates or lattices. Built-up beams are chiefly used as structural elements under compression, such as columns or chord members under compression in trusses. They are used particularly where the danger of buckling necessitates an increase in the cross-sectional radius of gyration of some member, that is, a reduction in the member’s flexibility. In such cases, the cross-sectional components of a built-up beam can be separated sufficiently to prevent buckling and then connected by single-or double-diagonal crossbars or by batten plates.