ABSTRACT

Two aspects of structural behaviour are of paramount importance. If the internal stress distribution in a structural member is examined it is possible, by integration, to describe the situation in terms of 'stress resultants'. In the general threedimensional situation, these are six in number: two bending moments, two shear forces, a twisting moment and a thrust. Conversely, it is, of course, possible to work the other way and convert stress-resultant actions (forces) into stress distributions. The second aspect is that of deformation. It is not usually necessary to describe structural deformation in continuous terms throughout the structure and it is usually sufficient to consider values of displacement at selected discrete points, usually the joints, of the structure.