MANAGING OLD BRIDGES

Many bridges of Italian road and railway infrastructural networks are between 50 and 150 years old. The building typologies, the technologies and the materials used for these bridges were very different from those used today, and so were the traffic loads considered for the structural checks. Although such bridges still provide adequate functional and structural performances, nevertheless they require specific inspections and maintenance operations, together with static and seismic adjustment interventions. This paper gives an account of studies and rehabilitation works carried out on a group of bridges located in the North of Italy and belonging to the main typologies used in the years between 1850 and 1970. Even if on a limited, yet meaningful, temporal basis, this paper tries to draw up a balance of what has been surveyed and to outline some remarks regarding the maintenance of the past and the design of the future.