Experimental behaviour of fibre reinforced concrete bridge decks subjected to punching shear

The ultimate behaviour of thin reinforced concrete structures, such as slabs, can be governed by the punching due to point loads. This premature brittle failure mode can occur in bridge deck slabs, often subjected to severe conditions of loads concentrated in small areas, and characterised by a reduced thickness. In this kind of structures a proper punching reinforcement is not applicable, even if the local and global behaviour can be improved by the addition of short fibres. The adoption of fibre reinforced concrete (FRC), indeed, can increase the punching shear resistance as well as the absorption energy capacity.Main object of the work is the evaluation of the influence of steel fibres on the punching shear behaviour of bridge slabs. Reinforced concrete slabs with and without steel fibres, having a geometry suitable for the simulation of the actual behaviour of bridge deck slabs, have been tested. Furthermore the case of load applied close to the supports, causing shear failure, is experimentally analysed. The obtained results are compared and discussed.