Beams and stringers. Lumber of rectangular cross section, 5 in (127 mm) or more thick and 8 in (203 mm) or more wide, graded with respect to its strength in bending when loaded on the narrow face.

Whether you work in construction or in a wood shop, plywood is a material you can't avoid. I've used it outdoors to sheath ...

When three or more sawn lumber elements not exceeding 4 inches in thickness and spaced not more than 24 inches apart are joined by a transverse load-distributing element, the bending stress may be ...