Bearing Capacity of Transversely Prestressed Concrete Deck Slabs

The Netherlands has a large number of thin, transversely prestressed concrete bridge decks, cast in-situ between flanges of prestressed concrete girders dating back to the 1960s and 1970s. These bridges are critical in shear when analyzed using EN 1992-1-1:2005; however, in reality, they show no significant signs of distress, possibly because of residual bearing (punching shear) capacity arising from compressive membrane action. Since these bridges are old, it is an astute approach to check whether they can be used for a few more decades, provided they are safe and reliable against modern traffic loads. The results could then be applied to a wider range of structures, especially in developing countries facing economic constraints. A prototype bridge was selected and experimental, numerical and theoretical approaches were used to investigate its bearing capacity. Respective coefficients of variation of 11% and 9% were obtained when the experimental and the finite element analysis punching loads were compared with the theoretical results. This led to the conclusion that the existing transversely prestressed concrete bridge decks still have sufficient bearing capacity and considerable cost savings can be made if compressive membrane action is considered in the analysis.