An engineered structural element that uses groups of rigid triangles to distribute and transfer loads is called what?

• A. Truss
• B. Girder
• C. Arch
• D. Frame

Answer: (A)

This item tests how triangular configurations in a structure transfer loads by converting them into forces along members. The term that fits this description is a truss. In a truss, straight members are connected at joints to form groups of triangles. Triangles are inherently rigid, so they hold their shape under load, which keeps the overall framework stable. This stability means external loads are carried mostly as tension or compression along the members, rather than bending the members themselves. That makes trusses efficient for spanning lengths with relatively little material while distributing loads to the supports.

Contrast this with a girder, which is typically a single large beam spanning supports and bending under load rather than distributing it through a triangular network. An arch relies on its curved shape to push loads as compressive forces along the curve into the supports, not a lattice of triangles. A frame, while also carrying loads through connected members, does not inherently use triangulated geometry to prevent deformation and can be more prone to racking unless triangulated or otherwise braced.