Improvements to La Contessa tunnel, in Perugia province, aim at increasing driver safety. In addition to previous refurbishment measures carried out by ANAS, the national road administration, the works included a new internal cladding and, in the unlined section of the tunnel, a waterproofing membrane to eliminate water infiltrations. The tunnel also needed improvements to bring it up to new European standards and replace outdated equipment, which required to install new lighting, ventilation fans, atmosphere monitoring devices, and automatic management and real-time control systems of the equipment.
The La Contessa tunnel is on ex road SS 452 in Perugia province’s Gubbio municipality in Umbria, central Italy. It is a 55 sq m cross-sectional, 1,185 m-long single bore tunnel, whereof 94 metres in cut-and-cover with open cut windows.
The La Contessa tunnel crosses a marly and arenaceous rock formation, composed of thin stratified marls intercalated with arenaceous and calcareous layers. From the portal on Gubbio side up to more than three quarters through the tunnel, the stratification heads northeast, inclined at about 50 degrees, while near the other exit (Fano side), the layers are oriented southwest, thus shaping a sinclinal fold which axis runs at a distance of about 200 metres from the tunnel exit. The presence of arenaceous and calcareous strata, characterized by good permeability, favours groundwater circulation in the rock mass, which has been the cause of water ingress observed inside the tunnel.
For years, a comprehensive refurbishment of the tunnel has been needed. The Perugia provincial council approved the comprehensive makeover of the tunnel, for a total price tag of EUR2.1 million, financed by the region of Umbria. The tunnel refurbishment works include the upgrade of its electrical equipment, for an amount of EUR1.04 million, its ventilation and rack-mounted power supply (EUR1.06 million). The complete refit forms part of the investment programme that the province of Perugia is carrying out in the structures connecting with the bordering Marche region. Works began in September 2006 and will be concluded in September 2007.
The project owner is the province of Perugia on behalf of the region of Umbria. The design, management and safety coordination during design and construction have been assigned to Cooprogetti, a consultancy based in Gubbio. The province of Perugia is responsible for the construction management. Structural works have been performed by Techno Consol, based in Ponte Felcino (Perugia), the electrical equipment has been supplied and installed by Cosmos Consalvi from Magione (Perugia) and the ventilation equipment has been installed by Carlini Signal headquartered in Pontegaleria (Rome). Visit www.provincia.perugia.it, www.cooprogetti.it and www.technoconsol.it
The refurbishment works to modernise the tunnel include:
- laying 50 mm sub-horizontal pipes provided by Milan-based Greenvision Ambiente (Italdreni division) to drain water inflows, coupled with stainless steel connectors to the existing lining. Visit www.italdreni.it/it/Azienda/index.htm
- installing approx. 150 metres of new geocomposite, a waterproofing membrane supplied by Flag of Bergamo, concrete formwork (concrete supplied by Gubbio Srl and cement by Colacem) with IPE120 steel arches and welded mesh. Visit www.flag.it and www.colacem.it
- shotcreting approx. 90 metres of the crown and concreting the walls with reinforced concrete;
- building a new water drainage system;
- reinforcing the 94 m-long cut-and-cover tunnel segment and its window-like cut out openings by injecting waterproof mortar, supplied by Kimia of Ponte Felcino (Perugia), behind the lining, installing Dywidag anchored bolts glued into the concrete with epoxy resin of Kimia and Vorpa of Riccione, laying 50 mm-diameter sub-horizontal pipes and applying Intrasit Dichtschlämme waterproof mortar. Visit www.kimia.it, www.dywidag-systems.com and www.vorpa.it
- installing new electrical equipment, consisting of lamps supplied by Grechi Illuminazione of Magenta (Milan) along the entire tunnel length and reinforced lighting at the entrance and exit, stainless steel metal cable trays supplied by Femi-CZ located in Rovigo, and cables supplied by Aristoncavi (Vicenza) and Prysmian (Milan). Visit www.grechi.com, www.femicz.it, www.aristoncavi.com and www.prysmian.com
- installing a new ventilation system, consisting of eight jet fans provided by CBI, CO-OP gauges and anemometers from Raet of Sieci (Florence), and thermal-sensitive wiring. Visit www.cbifans.net and www.raetsrl.it
- installing a rack-mounted power supply (Ediltevere of Siena), consisting of low and medium voltage components supplied by ABB of Bergamo, a generator by CME (Costruzioni Manutenzioni Elettromeccaniche) based in Chiusi (Siena), an emergency generator by SB Power System of Arezzo and management software by ABB. Visit www.abb.it, www.cmesrl.it and www.sbpowersystems.it
Today, refurbishment works of the La Contessa tunnel are nearing end, with just the road asphalting still to be done, which is scheduled on 6th and 7th August. Then the tunnel will be inaugurated, a few weeks ahead of schedule. To view photos click http://www.tunnelintelligence.com/upload_casestudies/Ti32_Pix_Contessa_0708.pdf 32/07.
