Hydraulic upgrading of the railway crossing over the Borghetto Stream at km 143+367 of the Genova Sampierdarena – French Border line, in the Municipality of Bordighera (IM).

Project objective

The intervention aimed to achieve the hydraulic upgrading of the railway crossing over the Borghetto stream, which became necessary because the existing bridge with 8.00 m clear span was hydraulically incompatible with the Borghetto–Vallecrosia Basin Plan.
A general widening of the channel cross-section was designed along the reach between the outlet of the upstream underpass used as a parking area and the bridge on Lungomare Argentina downstream, together with the construction of a new crossing structure with 16.00 m clear span.
The project included demolition of the existing bridge, casting of the new reinforced-concrete structure (foundation slab and side abutments) and installation of two new steel girders, one for each track, simply supported on the new substructure.
In order to carry out the works without significant interruptions to railway traffic beyond those already scheduled, temporary “Travi Bologna” bridges were installed in advance to support the tracks during construction, in turn supported on reinforced-concrete beam seats founded on Ø600 mm piles.
In addition, in the lateral areas adjacent to the tracks and outside the railway right-of-way, temporary excavation support works were provided consisting mainly of Berlin-type micropile retaining walls, faced with reinforced-concrete panels to form the permanent bank protections.

Main works

Steel bridge
The new crossing structure consists of two stiffened box-girder steel decks, with an overall length of 17.96 m and a design span (between bearing axes) of 17.20 m.
A reinforced-concrete slab was cast inside the box, incorporating Ø200 mm PVC pipes to reduce the overall weight of the structure; above the waterproofing, ballast and track were installed.
The structure also includes a lateral service walkway on dedicated brackets.