An experimental study on the ultimate behaviour of simply-supported post-tensioned composite slabs

Abstract

Post-tensioned composite steel-concrete slabs consist of thin-walled profiled steel sheeting, post-tensioned strands and concrete. This paper presents the preparation and results of two ultimate test series aimed at evaluating the contribution of the profiled sheeting on the load carrying capacity of this form of construction, and whether this is affected by time effects. For this purpose, six samples were prepared and tested to failure in a simply-supported static configuration by means of two transverse line loads applied near the mid-span. These consisted of two post-tensioned solid slab and four post-tensioned composite ones cast using Stramit Condeck HP® and Stramit PrimeForm® profiled sheeting. The flexural strengths observed for the composite specimens prepared with Condeck HP and PrimeForm profiles were in average 77% and 20% greater, respectively, than the moment capacity of the post-tensioned solid slab counterpart. These values did not appear to be affected by time effects for the material and geometric properties considered in this study. All samples exhibited a ductile response and all tests were terminated due to concrete crushing. A theoretical model was proposed to account for the partial shear connection behaviour of the composite slabs. The model was then applied to evaluate the influence of different geometric and material parameters on the moment capacity calculated for different post-tensioned composite slabs. It is expected that further comparisons with experimental results need to be carried out to properly validate its adequacy for use in routine design.