Engineering and Construction

With large, old-growth trees no longer readily available, very large timber  beams are usually built up of laminations or strands rather than sawn. Such beams are stronger and more  dimensionally stable than sawn wood  beams and can be made in the exact  size and shape desired (Figures 4.20  and 4.21). Hybrid or FRP reinforced  glulam beams, can be useful when especially lon- ger span are needed or heavy loads  must be supported.

Figure 4.20 Installing tongue-and-groove roof decking over laminated beams and  girders.

Figure 4.21 This roof uses glue-laminated beams to support proprietary long-span trusses made of wood with steel tube diagonals.