Structural assessment of a stock of motorway viaducts located in north Italy: results, statistics, and intervention

This paper provides indications on the maintenance status of 53 viaducts located in the main motorway sections of northern Italy. The viaducts are characterized by reinforced concrete piers and prestressed reinforced concrete or steel decks. For each viaduct, structural analyses are performed to assess the safety according to the rules defined in the Italian Guideline about the risk management, safety evaluation and existing bridges monitoring. The results of the analyses are expressed in terms of appropriate status (operability, practicability) of the viaducts, following the Italian National Code requirements. The results are statistically analyzed considering the viaducts’ age, the geometrical and material characteristics of the piers, and the features of the decks. Recurring structural problems linked to the maintenance are also identified and considered in terms of viaducts’ age and periodic tests performed for the status identification. The statistical analyses here performed also provide the intervention’s time to upgrade the viaducts in order to fit the appropriate structural status prescribed by the Code. Moreover, for the studied viaducts, the analyses give traffic and loads limitations to be respected during the time window in which the bridges are interested by the retrofitting works.