The bending moment is the point at which an element, such as a beam, is acted upon by external forces on one side and bends. The bending moment and shearing force of a beam are important factors to consider in the construction of buildings.
To properly support a beam, the bending moment must balance against the internal load capacity of the beam. A complex equation is used to determine the bending moment and shearing force of a beam that allow the beam to be properly supported. A positive bending moment makes the beam concave in an upward direction, while a negative bending moment bends the beam downward.