Gotthard tunnel, Switzerland

With two parallel single track tunnel tubes over a length of 57 km, the new Gotthard base tunnel through the Swiss Alps is the longest railway tunnel in the world. Construction of this line will be completed in four sections by different joint ventures. For construction of the Bodio/Faido section by the Consorzio TAT, the so-called "worm" will be deployed several kilometres behind the tunnel boring machine and its back-up systems in the east and western tubes.

The supply JV MSD Dresden and Bernold-Ceresola AG were awarded the contract to produce and install a pipe bridge installation to the inner vault (intrados) lining - called the "worm“ - from its customer Consorzio TAT.

Each "worm" is around 600 m long and weighs approx. 1900t . It is used as a working platform on which the downstream work and production of the inner concrete vault (intrados) can take place and at the same time, as a pipe bridge installation it provides the cable and pipe routing for high-voltage cables and cooling water pipes. Below this, all work can take place on twin tracks without being affected by the train traffic to supply the TBM.

Our partner, Bernold-Ceresola AG, is responsible for the formwork, the concreting equipment, the concrete curing/seasoning and the corresponding peripherals. MSD planned, delivered and installed the gantries and the technical equipment for the remaining functions of the installation. This area consists of:

Pipe dismantling gantry

2 gantries with reels for 2 hoses with DN 200 and a length >144 m and one pipe dismantling gantry with appropriate cranes and other infrastructure are used to dismantle the pipes between the installation and the TBM

Head gantry

This gantry includes part of the infrastructure for supplying the vault construction site (medium-voltage system, compressed air system, fire-extinguishing system, etc.) The high-voltage cable reel for temporary supply of the TBM is also accommodated there. This gantry provides one of the main accesses of the personnel arriving by train. Gang containers / site modules complete the equipment.

Gantry reprofiling and vault preparation

In this, approx. 250 - 270 m long area, all preparation work for the subsequent concreting is carried out. The gantries are therefore equipped with working platforms, cranes for material transfer, a powerful suction plant and storage and work areas. These work areas provide space for other necessary equipment and installations for carrying out reprofiling, safety and cleaning work on the vault.

Middle gantry

This gantry accommodates a hydraulic walker with corresponding infrastructure which, in interaction with rail clamps, also hydraulically actuated, is used for the everyday advance movement of the whole installation of approx. 24 m.

This is followed by the 108 m long concreting and curing area of the inner vault (Bernold-Ceresola AG).

Rear gantry

This gantry contains the same functional infrastructure as the head gantry

Pipe advance

As in the pipe dismantling, here there are two hose reel gantries and a construction gantry whose infrastructure is used for continuous operation without interruptions and construction of the tunnel pipes at the end of the vault site.

The individual gantries are equipped with lighting and emergency lights and with signalling and safety equipment according to the workplace and health & safety guidelines.

Equipment to be provided on site by the customer, such as weather coolers and other infrastructure supplement the installation.

In total, with this perfected structure in both tunnel tubes, 14 km concreting work will be carried out in each for the Los Bodio and around 11 km for the Los Faido tunnel. The finished Gotthard base tunnel is expected to open in 2015.

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