Grade Stress Level
The allowable stresses shown in Table 3.10 are divided into three different levels, which are related to the grade of the plywood. Research indicates that strength is directly related to the veneer grade and glue type. The derivation of the stress level is as follows:
• Bending, tension, and compression stresses depend on the grade of the veneer.
• Shear stresses do not depend on the veneer grade, but do vary with type of glue.
• Stiffness and bearing strength depend on species group, not veneer grade.