The linear elastic analysis is over-conservative and not suitable to predict the actual response of continuous steel-concrete composite beams. Actually the structural response is influenced by the non-linear behaviour of component materials for each load level, both at ultimate and serviceability limit states. Therefore the modern codes [01, 02] permit to carry out either linear elastic analyses with some moment redistribution or rigid plastic analyses. The former analyses can be employed both to check the maximum deflection at serviceability and to verify the beams at collapse, whereas the latter can be used at the ultimate limit state only. The moment redistribution limits proposed by codes depend only on the steel cross section.
In this paper, through a wide numerical analysis carried out considering most of the governing many parameters, the permissible moment redistribution limits for continuous steel-concrete composite beams at ultimate limit state is investigated.
