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.

It should be noted that Table 3.10 should be read in conjunction with Tables 3.11 to 3.14.