Assessment of shear strength of existing prestressed concrete bridge beams: Full-scale tests and numerical simulations

The obsolescence and the end of service lifetime of a big portion of our infrastructure, culmin- ated with recent catastrophic bridge collapses, determine an increasing need to implement monitoring activities and safety assessment of existing bridges and viaducts. As stated in numerous studies and experimental evi- dence, shear strength is one of the critical issues concerning existing bridges. In order to deepen the knowledge on structural shear behavior, an experimental campaign on full-scale prestressed concrete girders sampled from an existing structure has been performed in the structures laboratory of the University of Pavia (Italy). This study illustrates the results of experimental tests and numerical finite element simulations, which have been performed both to obtain a comparison with experimental data and to study the main contributing factors to the collapse of the girder for shear type failure. The failure strength obtained from experimental testing has been compared with the shear strength calculated according to different strength models presented both in design codes and in the literature; therefore the accuracy of such models will be assessed in order to define the most suitable approach to assess girder shear strength.