Investigation of Drainage Pipes in the Gotthard Base Tunnel

In the spring of 2010 in the Bodio section of the Gotthard Base Tunnel there were indications that the plastic pipes of the drainage system that were embedded in concrete did not conform to the work contract. The suspicion arose that the pipes were not made from new material but partly from recycled material. AlpTransit Gotthard Ltd therefore initiated investigations in all sections of the Gotthard Base Tunnel. First results confirm that some of the piping material that was installed does not conform to the specifications of the work contract.

AlpTransit Gotthard Ltd commissioned tests of random samples from all sections of the Gotthard Base Tunnel. In the Erstfeld, Amsteg, Faido and Bodio sections, the results showed that in some of the samples no new material had been used. A total of approximately 250 km of drainage pipes has been installed. Some 150 km could be affected by the problem. However, the 16 random samples are not representative of the entire length. Further random samples are therefore currently being taken in the tunnel, and the investigations are being deepened.

For the same reason, it is also not possible at present to say whether these pipes must be replaced or reinforced. This question can only be answered when the results of the additional investigations of the material characteristics and durability become available. Some of the tests can take up to one year to perform. This means that the costs for possible replacement also cannot be estimated at present. AlpTransit Gotthard Ltd will, however, rigorously enforce all contractual and legal consequences resulting from this situation.

During the entire construction period of the Gotthard Base Tunnel, AlpTransit Gotthard Ltd has required the construction contractors to present evidence of the quality of the materials that are installed. All of the certificates presented by the quality-certified suppliers stated that the specified quality was supplied. The locally responsible construction managers also confirm that this was the case.