The one-dimensional beam element is assumed to be axially rigid, meaning that there will be no axial displacement (u) along the beams centriodal axis. This implies that forces will only be applied perpendicular to the beams centriodal axis. The one-dimensional beam element can be used only when the degrees of freedom are limited to vertical displacements (perpendicular to the beams centriodal axis) and rotations in one plane. If axial displacements are present then a one-dimensional bar element must be superimposed with the one-dimensional beam element in order to obtain a valid solution.