What best defines a truss in structural framing?

• A. A curved, single-member beam
• B. A framed structural unit made of triangles in one plane
• C. A solid block of concrete
• D. A sheet of plywood with studs

Answer: (B)

A truss is a framed structural unit made up of straight members connected at joints to form triangles in a plane. That triangulated arrangement is the key: triangles keep the shape from deforming and allow the members to carry loads mainly as axial tension or compression rather than bending. By distributing forces through many lightweight members, a truss can span large distances efficiently and with less material.

This is why the curved, single-member beam isn’t a truss—bending is the primary action there, not axial forces in a triangulated frame. A solid block of concrete isn’t a truss either—it's a single mass, not a network of connected members. A sheet of plywood with studs describes wall framing, which is a different way of creating structure and not a triangulated frame.