ABSTRACT
Section 13.2 describes action effects that are specific to composite beams, such as the effects of concrete shrinkage and effects due to temperature. The various methods of structural analysis that may be adopted for composite beams are presented in Section 13.3. In certain instances other possibilities beyond just a purely elastic calculation of the resistance of composite cross sections, for example analysis methods that take into account the elasto-plastic behaviour of composite beams, can be adopted. In particular, as shown in Figure 13.1, in span where the moments are positive, it is possible to consider plastic cross section resistance, while above the intermediate supports, where the concrete in tension is cracked, the resistance of the cross section comprising the steel beam and longitudinal slab reinforcement should be assumed elastic, or reduced elastic. Both the influence of the cracked concrete in tension on the stiffness of continuous composite beams and the response of these beams to the actions on them are treated as well in this section.
