Location
Pomezia (Rome)
Year
2019
Client
RFI - FS Group
Dimensions
41 ml (L) - 13.40 ml (W)
Introduction and Historical Background
The intervention was undertaken to upgrade the Rome–Formia railway line to the PC80 loading gauge, to allow the transit of larger-profile vehicles such as freight wagons, swap bodies, and containers. This upgrade forms part of the objectives set by the European Union to integrate the national rail network into the TEN-T corridors, as defined by Regulation (EU) No. 1315/2013. The aim is to improve the movement of people and goods, strengthening the single market and Europe’s overall competitiveness
During technical assessments, an interference was identified between the new PC80 freight gauge and the geometry of the bridge located at km marker 24+396 of the Rome–Formia track line. The main issue was found at the haunches of the central arch of the masonry structure, with an almost total encroachment into the thickness of the load-bearing arch, measuring 70 cm. Due to this critical condition, it was deemed necessary to demolish the existing bridge and replace it with a new structure to ensure unrestricted passage.
From a historical perspective, the idea of a direct railway connection between Rome and Naples dates back to 1861, the year of Italy’s unification. However, it was only in the early 1900s that a dedicated office was established to design the new “direct” Rome–Naples track line. The final project was approved in 1906, and construction began in 1909, although it was interrupted during the First World War.
Design
Demolition
Construction
Structural and technical testing
ANTE OPERAM
POST OPERAM
Design
The existing bridge, scheduled for demolition, is a masonry arch structure with three spans. The two smaller side spans, each with a 5.0 m clear span, are characterised by full-circle arches, while the larger central span, with a 15.0 m clear span, features a lowered arch. The bridge therefore consists of two abutments and two piers, each 2.0 m wide, for a total thickness of 4.0 m.
The new deck is made of steel with a reinforced concrete slab and has a total length of 41 m (40 m between bearing axes). It is composed of two top-chord double T-girders (with a 12.60 m centre-to-centre spacing), connected by solid-web crossbeams positioned beneath the longitudinal beams at a spacing of 2.5 m.
To ensure the new structure blended into the surrounding context, and in agreement with the Heritage Authority, the exposed steel girders were clad with weathering (Corten) steel plates.
Construction phases
The replacement of the railway overpass at km marker 24+396 on the Rome–Formia track line was carried out in two phases, each involving a complete interruption of rail traffic. During the first closure, the existing masonry structure was demolished, and the new reinforced concrete abutments were constructed on large-diameter piles.
For the installation, two reinforced concrete slabs were built: one at track level for the lifting crane, and another at a higher level for assembling the lattice-boom crane and for the transit of the SPMT (self-propelled modular transporters), used to move the new steel span into position for lifting.
The steel span, manufactured in segments at a steel fabrication facility assembled on site on temporary steel supports, was installed during the second interruption of rail traffic. The erection of the steel deck, with a total weight of 450 tonnes, was carried out using a 650-tonne lattice-boom crane. After lifting and final positioning of the span, the bridge’s reinforced concrete deck slab was casted.
