# Introduction to structural archetypes

Structural archetypes are aspects of structural form that enable efficiency in the resistance of load. In other words, they produce structures which are strong from a minimal amount of material. Examples are the I-shaped cross-section and the triangulated beam.

Why are structural archetypes important?

Because the form of a structure – both its overall form and the detailed shapes of its elements (cross-section and longitudinal profile) – determine the efficiency with which material is used. Efficiency determines embodied energy and carbon footprint.

All structures must have adequate strength (see Structural Principles). Efficient structures achieve their required strength with small quantities of material. Inefficient structures require large quantities of material.

Efficiency or inefficiency results from the shape of the structure. The reasons for this are explained in this section of the website under the headings Form and Internal Force Type, Overall Form and Detailed Form.

Constructability is another determinant of embodied energy. The interaction of form and constructability is discussed in Economy of Means.