Professor Emeritus, School of Civil, Environmental and Land Management Engineering, Politécnico di Milano, Italy
The collapse of the Polcevera Viaduct drew attention to the general state of infrastructural networks all over the world. This Lecture recalls some noteworthy bridge failures (or near failures), containing elements which may be useful to improve the current criteria for bridge inspection and safety assessment.
In recent history, that of the Polcevera viaduct in Genoa has been one of the most severe collapse in terms of number of victims, relevance of the bridge and economic repercussions. In this Lecture, we will summarize the original design criteria of the bridge, retrace the demanding construction phases and give a brief account of the inspections and the main maintenance works carried out during its service life. In the final part, we will report about the forensic investigations carried out after the collapse.
After the Polcevera collapse and other such events, the notion that infrastructural works are not everlasting reached the general public, and consensus grew among networks managers and policymakers about the need to implement adequate controls and investment programs in maintenance. With regards to this, the note will also present a summary of the initiatives underway in Italy to extend controls and verifications of existing bridges and to plan the renewal of the national infrastructural network. Reference will be made to the activities of the Special Committees of the Italian Ministry of Infrastructure and Transport, whose task is to draft new guidelines for bridge inspection and maintenance and, subsequently, for assessing and repairing prestressed and ordinary reinforced concrete bridges. Similar initiatives have also been promoted by local authorities in partnership with academia, such as the study launched by the Lombardy Region and the Politecnico di Milano, concerning the analysis and monitoring of bridges, tunnels and roads of the regional infrastructural network.
The aim of this Lecture is not to provide any specific conclusions: recent events can only lead us to draw the right lessons from past experiences in terms of design, construction, control and maintenance, and to underline the great responsibilities engineers hold towards the public safety and the economy of a country.
Key words: bridge failures, hidden collapse causes, safety of prestressed bridges, Polcevera viaduct collapse.