Statics of Beams and Frames

Abstract

In the case of trusses, discussed in the previous chapter, the statics of the individual bars forming the truss was fairly simple, because a bar can only carry a single force component – the axial force – and furthermore this force is constant throughout the bar, because of the simplifying assumption that no loads are applied along the bar. An alternative way of carrying loads is by using frame structures, made up by connecting beams. It is an important characteristic of beams, that they can carry transverse loads by offering resistance to bending. The internal forces in beams and frames constitute an important aspect of these structures, often called ‘statics of beams and frames’. For a given structure and load distribution the section force distribution enables calculation of the deformed shape of the structure as well as the severity of the loading of the individual sections and thereby assessment of the strength of the structure. The present chapter gives a precise definition of section forces and presents analysis methods for the distribution of section forces in beams and frames.