Punching shear of post-tensioned steel fibre reinforced concrete elevated slabs without longitudinal reinforcement

The combined use of steel fibre reinforced concrete and post-tensioning for the construction of elevated slabs offers many advantages. The flat slabs are commonly designed for bending, but punching shear represents the most dreaded failure due to its brittleness and a scanty reliable prediction. Previous studies have highlighted the individual contributions of post-tensioning and fibres, but only a limited number of post-tensioned fibre reinforced concrete slabs has been analysed. This research aims at investigating the contribution of steel fibres to the punching resistance of post-tensioned elevated slabs, without considering the contribution provided by the longitudinal reinforcement. The experimental results for post-tensioned plain concrete and steel fibre reinforced concrete slabs are presented, highlighting the positive effects of fibres and the limits of existing design formulations.