Buckling of the steel component of a composite member caused by shrinkage and creep of the concrete component

The effects of shrinkage and creep in conventional reinforced and prestressed concrete members are quite well understood, and the effects of these time-varying characteristics of the concrete component on the deflections of composite beams and columns have received a good deal of attention in recent years. However, creep and shrinkage effects may cause a redistribution of internal actions within a composite member, which increases significantly the compression within the steel component, and that may therefore lead to considerations of the possible buckling instability of the steel component. This paper reviews the research work that been documented only quite recently, which has been undertaken on the potential for composite structures using a thin external skin with a concrete infill to buckle locally, and the possible instabilities that may arise in the negative moment region of a continuous composite beam, due to the shrinkage and creep of the concrete. This paper also puts the possibilities of these instabilities into a practical perspective, indicating where this unique type of steel buckling may need to be a design consideration in the most efficient use of steel-concrete composite construction.