Success Story Details
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WHERE EVEN THE CONCRETE SPRAYING MACHINES NEEDED 4 WHEEL DRIVE AND 4 WHEEL SPRAYING
Along Europe's longest national highway, there is a 9.1km section between La Herradura and Taramay that connects the cities of Cádiz and Gibraltar in the South of the Iberian Pensinsula and Barcelona in the North East.
It runs over a distance of 1.8km with a 4-lane carriageway and then over a distance of 7.3km in each direction of traffic as a separate route through three twin-bore tunnels and four bridges.
The Challenge :
• Shotcreting on Europe’s most high ticket roadway.
• Backing up advance work in each of the three twin-bore tunnels in a length of 5,04km along the total stretch of 9km.
The Solution :
The bridges consisted of two parallel girders but the tunnels in each direction of traffic were designed as single structures. All of the six bores had a full section of approximately 110m³ and the work progressed at 6 to 10 m per day, depending on whether the supporting arches type THN 21 and THN 29 needed to be installed or not.
The three mobile shotcrete Sika®-PM500 P spraying devices were first used to secure the slope area around the portals and then to secure the tunnel excavation work according to the new Austrian tunnel construction process.
The 4 wheel drive and 4 wheel steering machines easily maneuvered through the challenging terrain and showed off their incredible resilience in this project.
The horizontal automatic system on the spraying arm of the Sika®-PM500 P proved to be very helpful in the shotcreting work in the six LA HERRADURA tunnel bores. This device enabled the cradle to be extended by 3m and held in a horizontal position. In conjunction with the highly maneuverable head of the spraying nozzle. This resulted in an extraordinarily even spray pattern with little rebound.
All of the Sika®-PM500 used at the LA HERRADURA site were equipped with a liquid metering device (Sika®Aliva-403,5) and one or two tanks for concrete acceleration (of a capacity 1.000l each). As the site already provided compressed air lines in the tunnels, the spraying devices were not supplied with their own compressors. A total volume of 75.000m³ of shotcrete was placed in the six tunnels.
While pumping of concrete for the tunnels as well, there was a monopoly of Putzmeister machinery. Approximately 80,000m³ in strength class C40/50, 180.000 m³ high strength concrete C 60/75 and 100.000m³ in strength class C25/30 was placed using stationary concrete pumps, which had been previously used for building the bridge piers.
The section was initially built by U.T.E. LA HERRADURA, a joint venture comprising of the construction companies PLODER S.A., AZVI S.A. and OBRAS SUBTERRÁNEAS S.A.
Project Partners
The section was initially built by U.T.E. LA HERRADURA, a joint venture comprising of the construction companies PLODER S.A., AZVI S.A. and OBRAS SUBTERRÁNEAS S.A.