Following the flooding events that struck the lower Tronto Valley in 1992, the Interregional Basin Authority commissioned the Hydraulic Institute of the Faculty of Engineering in Ancona to draw up a hydrological study of the Tronto River from its mouth to Ascoli Piceno.
What emerged from simulations carried out, was that the morphology of the riverbed at its mouth would not have allowed the outflow in case of flooding, an event that could have triggered its overflowing. The Basin Authority decided to proceed with the reconstruction of the road and railway bridge and the demolition of the existing one to adapt the hydraulic section. Then, the implementation of the hydraulic system and the relocation of existing activities and buildings were carried out. A monolith was then built on the east side of the railway (towards the sea) starting with the thrust wall and the launch slab on which the sheaths were placed.
At this stage, the monolith base slab, the side walls and the central part with the rostrums were implemented. The work was completed adding the upper slab with connecting beams.
The thrust technique to construct railway underpasses consisted in building the monolith in an off-site construction (monolithic), which was subsequently placed under the tracks by using a hydraulic jack (oleo-dynamic pump).
During the transfer, the tracks were strengthened by a set of beams placed parallel to the same and connected by crossbeams at a short distance to support the rails; this longitudinal strengthening structure was put transversely on steel beams (maneuvering beams) with the function of supporting the whole while sliding on the extrados during the movement of the same.
The technology for a temporary bridge track support, as well as allowing railway maintenance, has also provided a low environmental impact. The pile driving phase of the monolith was preceded by a reinforcement of the right abutment of the bridge (north side), consisting in the realization of foundation diaphragms surmounted by reinforced rostrum shaped concrete walls, closed on top by a slab, also in reinforced concrete; all to guarantee both the abutment and the adjacent monoliths of the project against the hydraulic pressure.
SCHEDA LAVORO
