9.1 Chapter 9: Column Analysis and Design Introduction Columns are usually considered as vertical structural elements, but they can be positioned in any orientation (e.g. diagonal and horizontal compression elements in a truss). Columns are used as major elements in trusses, building frames, and sub-structure supports for bridges (e.g. piers). • Columns support compressive loads from roofs, floors, or bridge decks. • Columns transmit the vertical forces to the foundations and into the subsoil. The work of a column is simpler than the work of a beam. • The loads applied to a column are only axial loads. • Loads on columns are typically applied at the ends of the member, producing axial compressive stresses. • However, on occasion the loads acting on a column can include axial forces, transverse forces, and bending moments (e.g. beam-columns). Columns are defined by the length between support ends. • Short columns (e.g. footing piers). • Long columns (e.g. bridge and freeway piers). Virtually every common construction material is used for column construction. • Steel, timber, concrete (reinforced and pre-stressed), and masonry (brick, block, and stone). The selection of a particular material may be made based on the following. • Strength (material) properties (e.g. steel vs. wood). • Appearance (circular, square, or I-beam). • Accommodate the connection of other members. • Local production capabilities (i.e. the shape of the cross section). Columns are major structural components that significantly affect the building’s overall performance and stability. • Columns are designed with larger safety factors than other structural components.