RamArch – A90 San Fermo Tunnel renovation

PROJECT: A90 San Fermo Tunnel renovation
OWNER: Autostrade per l’Italia (Aspi)
CONTRACTOR: Tecne SPA
PURPOSE: Secondary internal lining reinforcement.
RAMARCH TYPE: Plain steel 8mm RAMARCH mesh, manufactured to BS standard
RAMARCH FINISH: Fully encapsulated in shotcrete.
DATE: 2022-23

The Tunnel Renewal Strategy program on the
Autostrade per l’Italia network is intended to
extend the useful life of the tunnels by a further
50 years through the creation of new linings,
designed to replace the original ones, also
guaranteeing adequate performance in the
event of seismic activity.
The 700m long San Fermo tunnel is located on
the A9 motorway, between Como and Chiasso
and was constructed in the 1970s. The
rehabilitation of the existing lining was
undertaken along the entire length of the
tunnel in which the a new structural lining was
installed with the application of highperformance
steel reinforced shotcrete founded
on cast in situ reinforced concrete walls along
the footings on either side of the carriageway.
The work plan regarding was divided into three
phases. In Phase 1, the RAMARCH system was
used to support a waterproof PVC sheet
membrane in areas of water ingress whilst the
sprayed concrete was applied robotically and
to provide structural reinforcement to the
secondary lining. The system was chosen
because of the rapidity of installation compared
to more conventional sprayed concrete
reinforcement systems such as lattice girders.