ABSTRACT
This chapter focuses on how we size beams for shear stress. It covers shear design for the common application of all lumber types. Shear is fundamental to how beams resist load. It holds the outer layers of a bending member together, causing them to act as one. The blades are perpendicular to the material, going in opposite directions. This creates a tearing of the material. In beam shear, the action is similar, but the movement of material is parallel to the length of the beam. The top portion moves relative to the bottom. Shear stability is not a concern in solid timber members. The sections are compact enough to not experience shear buckling. Shear strength rarely changes within a species, it is likely to control beam design of higher grade woods, rather than lower. In the single-span, simply supported beam, the shear stress is zero at the middle and maximum at the ends.
