Design Requirements and Bending Properties for Mechanically-Laminated Wood Assemblies
|Publication Date:||1 August 2010|
Purpose and Scope
The purpose of this Engineering Practice is to establish guidelines for designing and calculating allowable bending properties of mechanically laminated wood assemblies used as structural members.
The scope of this Engineering Practice is limited to mechanically laminated assemblies with three or four wood laminations that have the following characteristics:
The actual thickness of each lamination is between 38 and 51 mm (1.5 and 2.0 in.).
All laminations have the same depth (face width), d.
Faces of adjacent laminations are in contact.
The centroid of each lamination is located on the centroidal axis of the assembly (axis Y-Y in Figure 1a), that is, no laminations are offset.
Concentrated loads are distributed to the individual laminations by a load distributing element.
All laminations are of the same grade and species of lumber or structural composite lumber.
There is no more than one common end joint per lamination within a splice region.
The provisions of this Engineering Practice do not apply to assemblies designed for biaxial bending. The design requirements in clause 4, and allowable bending properties in clauses 5 and 6, are only for uniaxial bending about axis Y-Y (Figure 1a). Spliced assemblies with butt joints shall have sufficient lateral support to prevent out-of-plane (lateral) movement or buckling, and/or delamination in the splice region.
This Engineering Practice does not preclude the use of assembly designs not meeting the criteria in clauses 1.2 and 1.3.