A structural member that is fabricated from metal, reinforced or prestressed concrete, wood, fiber- reinforced plastic, or other construction materials and that resists loads perpendicular to its longitudinal axis. Its length is usually much larger than its depth or width. Usually beams are of symmetric cross section; they are designed to bend in this plane of symmetry, which is also the plane of their greatest strength and stiffness. This plane coincides with the plane of the applied loads. Beams are used as primary load-carrying members in bridges and buildings.