What is the term for a system composed of lightweight triangles that span long distances and resist distortion?

• A. Truss
• B. Frame trabeated
• C. Masonry arcuated
• D. Neolithic Period

Answer: (A)

This uses triangles to create a stiff, lightweight framework that can span long distances while resisting distortion. Triangles are geometrically rigid: once you form a triangle with three members, you can’t change its shape without altering the lengths of the sides. By arranging many triangular units and connecting them at joints, the structure carries loads mainly along the members in tension or compression, not by bending. This lets a truss span wide gaps efficiently with relatively little material, which is why you see trusses in bridges and roof supports.

Other terms describe different systems or ideas. A frame trabeated system relies more on rectangular frames that can bend under load, not the rigid, triangulated network of a truss. Masonry arcuated refers to arches and vaults in masonry, which distribute loads differently and don’t use a lightweight triangular lattice. Neolithic Period is a historical time frame, not a structural system.