What type of structural member is defined by an unsupported height to least lateral dimension ratio of not less than 3?

A structural member characterized by an unsupported height to least lateral dimension ratio of not less than 3 is classified as a column. Columns are vertical structural elements that primarily carry compressive loads and transfer these loads to the foundations. The specified ratio indicates that as the height of the column increases relative to its cross-sectional dimensions, it is considered slender. This slenderness can affect the stability of the column under load, thus defining it as a critical factor in its design and analysis.

When the height of a column is significantly greater than its width, it may be more prone to buckling, which is an important consideration in structural engineering. This is why the minimum ratio provides a guideline for distinguishing between columns and other structural members. Other types of structural members, like beams and plates, serve different purposes and have different loading characteristics that do not align with this specific definition. For instance, beams primarily resist bending and shear forces, while plates are typically two-dimensional elements that resist in-plane loads. Therefore, understanding the characteristics and classifications of structural members is essential in the fields of surveying, analysis, and design.