Punching shear strength of transversely prestressed concrete decks

In the Netherlands, there is a need to determine the capacity of bridge decks as a large number of them were built back in the 60’s and 70’s. Since then, not only a lot of additional safety requirements have been incorporated into the modern codes but the traffic flow has also increased drastically. The current research deals with this question by taking into account arching action or compressive membrane action (CMA) in transversely prestressed decks on concrete girders. CMA is a phenomenon that occurs in deck slabs with edges restrained against lateral movement by stiff boundary elements. This restraint induces in-plane forces in the slab affecting both the flexural and the punching shear capacities. Existing methods were modified and a MATLAB program was developed to include the effect of CMA and the transverse prestressing to calculate the punching shear capacity of bridge decks. It was concluded that transverse prestressing enhances the CMA and improves the structural behaviour. However, detailed experiments are being carried out to further investigate the effect of different parameters, like geometry of the deck and the Transverse Prestress Level on the punching shear strength