Fast preliminary assessment of simply supported prestressed concrete girder bridges using parametric analyses

The Italian Guidelines for existing bridges proposed a multi-level approach to manage the large stock of bridges in the national territory, starting from the census of the structures, then visual inspection and defects evaluation, evaluation of a “Class of Attention” (CoA), preliminary assessment up to accurate assessment of critical bridges or even network resilience for very important structures. After the assignment of the CoA, ranging from Low to High across five levels, bridges with Medium or Medium-High CoA have to be preliminary assessed, in order to prioritize further investigations. As many bridges are approaching their nominal life and are suffering from lack of maintenance, many structures could have a Medium or higher CoA, therefore a rapid method for preliminary assessment of bridge decks can help the management of large portfolios of bridges. In this study, a parametric analysis of the preliminary assessment of prestressed concrete girder bridge is performed, focusing on simply supported deck bridges, which is the most common typology. A large number of bridges is analysed using the Guyon-Massonnet-Bares method, evaluating both historical and current traffic load model design forces in order to perform the preliminary analysis of each case, considering several outdated codes and also different geometric parameters. All the results are then statistically analysed to provide a tool for the fast preliminary assessment of prestressed concrete girder bridges.