New design values went into effect approximately one year ago (June 1, 2013) for visually graded Southern Pine. These values had been approved by the American Lumber Standard Committee, and apply to new construction only.
To help explain some of the changes that were made, and which type of products were affected, Catherine Kaake, PE, of the Southern Forest Products Association, and Buddy Showalter, PE, of the American Wood Council, answered a series of Frequently Asked Questions, in their Structure Magazine article: Visually-Graded Southern Pine Dimension Lumber – New Design Values.
Among other questions, the article identifies which lumber properties have updated design values. These properties include:
|Bending (Fb)||Compression parallel-to-grain (Fc)|
|Tension parallel-to-grain (Ft)||Modulus of Elasticity (E and Emin)|
Design values for Shear parallel-to-grain (Fv) and Compression perpendicular-to-grain (Fc-⊥) remained the same.