| Since the late 1970's, an empirical method for designing bridge deck slabs, which takes into account the beneficial effects of compressive membrane action, has been incorporated into Ontario Highway Bridge Design Code. The new design method has achieved considerable savings in bridge deck reinforcement. It is considered that transverse prestressing of a bridge deck can achieve even more saving by reducing slab thickness and reinforcement requirements while enhancing serviceability. This thesis reports an extensive experimental and analytical investigation undertaken to study the punching behaviour of transversely prestressed bridge decks, and the effect of transverse prestress level.;It was found from this study that the transversely prestressed deck can be a feasible alternative in composite bridge deck design. The deck slabs exhibited high punching strength in the presence of strong compressive membrane action resulting from the transverse prestressing. The deck slabs also performed satisfactorily at service load levels. Further, for the transversely prestressed decks, it appears that deck design will be governed by serviceability limit states rather than ultimate limit states. The appropriate level of transverse prestress should be determined by crack control and temperature and shrinkage requirements. Analytical results from nonlinear finite element modelling correlated reasonably well with experimental observations. A method is proposed based upon the Hewitt-Batchelor model, which predicted closely the punching strength of the prestressed deck slabs.;Two 1/4.04-scale models of a single span and three-girder bridge, with a transversely prestressed deck, were constructed and tested in the laboratory. The main variable in the experimental study was the level of transverse prestress. A total of twelve deck panels with six different levels of transverse prestress were tested to failure under simulated wheel loading. Detailed nonlinear finite element models were developed using ANSYS to predict the punching shear failure of the prestressed deck slabs. A three-dimensional reinforced concrete element was used to model the nonlinearities of concrete, including cracking, crushing and plasticity. The punching strength of the bridge decks were also predicted using other punching shear models and code approaches. |
