TABLE OF CONTENTS Sawn lumber is manufactured in a large number of sizes and grades (Chap. 4) and is used for a wide variety of structural members. However, the cross-sectional dimensions and lengths of these members are limited by the size of the trees available to produce this type of lumber.
When the span becomes long or when the loads become large, the use of sawn lumber may become impractical. In these circumstances (and possibly for architectural reasons) structural glued laminated timber ( glulam) can be used.
Glulam members are fabricated from relatively thin laminations (nominal 1 and 2 in.) of wood. These laminations can be end-jointed and glued together in such a way to produce wood members of practically any size and length. Lengths of glulam members are limited by handling systems and length restrictions imposed by highway transportation systems rather than by the size of the tree.
This chapter provides an introduction to glulam timber and its design characteristics. The similarities and differences between glulam and sawn wood members are also noted.
The specifications for glulam permit the fabrication of a member of any width and any depth. However, standard practice has resulted in commonly accepted widths and thicknesses of laminations (see Ref. 5.6). The generally accepted dimensions for glulams fabricated from the Western Species are slightly different from those for Southern Pine glulams as given in NDS Table 5.1.3 (Ref. 5.1). See Fig. 5.1. Because of surfacing requirements, Southern Pine laminations...
