Experimental and analytical investigations on the shear capacity of prestressed concrete bridges

A recalculation according to Eurocode 2 (EC2) of bridges, which have been built in Europe before the introduction of EC2, shows a deficit of the existing shear reinforcement. However, prestressed concrete bridges have additional load-bearing reserves. Even refined analytical approaches do not sufficiently cap- ture the simultaneous effect of the concrete and reinforcement contribution on the shear capacity. Hence, it is important to verify the shear capacity of existing concrete bridges with a new improved design ap- proach. In this work, sixteen large-scaled shear tests (16,5 m continuous post-tensioned girders with uni- formly distributed loads) have been conducted. To examine the interaction of the concrete contribution and the strut-and-tie model, the specimens were built with low shear reinforcement and varying cross- sectional shapes. Finally, it will be shown that the service time of existing structures can be extended significantly by using the new analytical design approach.