The railway lines in Italy extend for over 16,000 km, along which more than 11,000 bridges and viaducts are located.
Many of them were created between the end of the 19th century and the first decades of the 20th century. Some were severely damaged during the war and later rebuilt.
The most common construction types are arch bridges (with one or more spans), made of masonry or concrete, and bridges with a reinforced concrete deck or a mixed steel-concrete structure.
Thanks to the wide structural safety margins adopted and optimal execution, most existing bridges are still in good static conditions today, despite their age.
Conversely, as regards the state of conservation, there is a general deterioration of the materials and structural elements, most often due to a loss of efficiency of the waterproofing system.
The deterioration produced by water percolation is visible through a wide range of symptoms: breaking of bricks, corrosion of reinforcement, washing away of mortar, disintegration of concrete, etc.
The rainwater that falls on the railway site, not intercepted by the waterproofing system and channelled into the drainage network, reaches the structural parts, triggering the degradation mentioned above.
