Some iron railway bridges of the nineteenth century in Italy; historical considerations and recent investigations

Due to their historical value the old structures of the iron railway bridges can be still considered to be studied for architectural and static interests. Despite their age, of at least a century and much more, old iron bridges are still been used in many secondary lines all over Europe, presenting unique safety assessment problems to the responsible agencies. These concerns stimulated investigations on some railroad iron bridges in South Italy. The paper presents a study involving evaluations of material properties, connections and external restraints, and the actual loads. Some dynamic tests with service train as well as with a mechanical excitation were performed. The results gave dynamic and static information on the structure, which were used to tune and improve the numerical finite element model. Finally, the “real” dynamic amplification coefficient was evaluated for different speed of the train, and compared with that one suggested by the Italian code.