Service behaviour of composite steel-concrete slabs with a simplified approach and a hygro-thermo-chemical-mechanical model for the non-uniform shrinkage evaluation

Composite steel-concrete floors are widely used throughout the world for building applications. These floors usually consist of composite slabs supported by steel beams in steel framed construction and of post-tensioned composite slabs carried by band beams in concrete buildings. The design of composite floors is commonly governed by serviceability limit state associated with deflection limits. Recent research has pointed out that a non-uniform shrinkage profile occurs in slabs cast on profiled steel sheeting. In this context, this paper provides a brief overview of the main factors influencing the service behavior of composite slabs and of a model capable of predicting their long-term deflections considering two approaches for the evaluation of the non-uniform shrinkage profiles, i.e. a simplified approach and a hygro-thermo-chemicalmechanical model. The adequacy of the proposed prediction models is then outlined by comparing the longterm deflections calculated with the proposed approach and those measured experimentally from long-term tests carried out on selected composite and post-tensioned composite slab samples that have been reported in the literature.