Beams are used extensively in structures, primarily in flooring systems for buildings and bridges. They belong to the line element category, i.e. their longitudinal dimension is large in comparison to their cross-sectional dimensions. Whereas truss members are loaded axially, beams are loaded normal to the longitudinal direction, and carry the loading by bending and twisting action. This mode is illustrated in below Fig . The transverse loading produces transverse deflection, which results in a nonuniform distribution of stress throughout the body.
