What is the primary force acting on a column in structural design?

In structural design, the primary force acting on a column is compression. Columns are vertical structural elements designed to support loads from above, such as floors, roofs, and other superstructures. When loads are applied to a column, they generate compressive forces that act along the length of the column, pushing down on it. This compressive force must be properly accounted for in the design to ensure that the column can safely carry the load without buckling, crushing, or otherwise failing.

In reinforced concrete structures, the design must consider the material properties of both concrete and reinforcement. Concrete is strong under compression but relatively weak in tension, which is why reinforcement is included in the form of rebar to help resist any tensile stresses that may arise due to bending moments or eccentric loading.

The other forces mentioned—flexure, tension, and shear—may also be present in conjunction with the compressive forces but are not the primary forces acting on a column. Flexure primarily affects beams rather than columns, tension forces are mitigated through the use of reinforcement in concrete columns, and shear forces usually arise at connections or in elements subjected to lateral loads, making them secondary in the context of columns subjected primarily to axial loads.