Assessment of a centenary iron bridge of the Domodossola-Locarno railway line

The Ferrovia Vigezzina - Centovalli is a 52.2 km local railway line that connects Domodos sola, Italy, to Locarno, Switzerland. The line was built between 1920 and 1923. On the Italian side, the longest bridge is the Mizzoccola Bridge, a continuous steel trussed girder on four supports, crossing the Toce River less than a kilometer away from Domodossola Station. The bridge was opened in November 1923, and it has been systematically monitored and maintained ever since. In 2013, SSIF S.p.A., in charge of the maintenance and management of the Italian side of the line, started implementing a plan that will involve the detailed inspection and/or refurbishment of all the bridges under the company supervision. This paper will briefly describe the inspections carried out on the Mizzoccola Bridge, discuss the main damaging factors, and then present preliminary Limit Analyses developed in designing the refurbishment works.