Chapter 4 - Sectional properties

Abstract

This chapter discusses the industry standards of shapes and sizes of structural elements keeping in mind constraints imposed by manufacturing technologies, transportation, handling safety, and serviceability requirements. With wood within each species, lumber is further classified by its size. Various grades of lumber are then identified for each size classification. The actual (“dressed”) sizes of lumber are currently 1/2 in. to 3/4 in. “Beams and stringers” and “post and stringers” are commonly used for structural purposes. Wide-flange shapes are commonly used for both beams and columns within steel-framed structures, wide-flange (W) sections have parallel flange surfaces, making it somewhat easier to make connections to other structural elements; these sections are manufactured in groups with a common set of inner rollers. Because reinforced concrete is cast-in-place, or site-cast, it is literally made at the building site, the only real constraint on the sizes and shapes of concrete structural elements is the willingness of architects, engineers, owners, and contractors to design the structure and assemble the framework into which the concrete and reinforcement is placed.