Applicazione delle Linee guida italiane alle valutazioni di sicurezza strutturale del ponte Corleone sulla tangenziale di Palermo

Abstract

The "nominal life" of a large part of existing reinforced and prestressed concrete bridges, in Italy, is expiring, often in the absence of ordinary or extraordinary maintenance. Consequently, the Italian infrastructural network is in a critical phase, followed by the alarmed awareness of the public opinion, especially after the collapse of the Polcevera viaduct. Specific guidelines on risk classifi-cation, management, safety assessment, monitoring of existing bridges have been issued by the Superior Council of Public Works in 2020, to address the emergency. Between ‘50s and ‘70s of the last century, important examples of reinforced and prestressed concrete bridges were built in Italy by the most famous Italian designers, and they have to be safeguarded by finding the appropri-ate strategies for their preservation. Among these, the Corleone bridge, an arch bridge on the Palermo ring road, designed in 1958, finds its place both from the historical design point of view and critical state of degradation. The Municipality of Palermo requested an accurate safety check of the bridge, in the light of the indications of the Ministerial Guidelines, to evaluate its operational per-formance and the conditions of its transit ability and/or its permanence in service, with indications on the retrofitting interventions. The working group investigated the shortcomings due to natural aging and lack of maintenance, highlighting the critical aspects connected to the current situation, with the presence of Gerber saddles in the deck and the necessary limitations to transit before the rehabilitation.