Most bridges that were built during the 1960s - 1980s were mainly designed in prestressed concrete. Nowadays, they represent about the 95% of the total number of bridges that are part of the Italian national transport network under the responsibility of private and public management companies. Existing bridges are naturally subjected to degradation mechanisms during their service life, due to environmental and operational events, leading to a decrease in performance, if also mechanical problems related to the transversal distribution of loads are added to this, serious problems can arise. It is important to underline that the development of stresses and the transfer of loads in a beam bridge is directly related to the relationship between transverse beams and longitudinal beams, in fact, the main structural function of cross-beams is to allow the correct transfer of loads in the transversal direction from the point of application of the load to the neighbouring beams.