ABSTRACT
The characteristics of internal reaction for a beam section are, as stated in the earlier chapters, the elementary internal reactions transmitted by the section itself. In the case of a plane beam (line of axis contained in the plane), there are three characteristics of internal reaction (Figure 5.1):
axial force, which is the component of the force tangential to the axis of the beam;
shearing force (or, more simply, shear), which is the component of the force perpendicular to the axis of the beam;
bending moment, which is the moment of the force that the two portions of beam transmit to one another, with respect to the section being considered.
