In the city of Erfurt numerous underground utility conduits for infrastructure supply in the city are operated by the SWE-Netz (Erfurt public utility group).

The utility conduits were built around 1970 and, since then, have been used to supply district heating, drinking water and power. Following reunification, they were used to retrofit gas supply pipelines and telecommunication and IT cables, without the need for underground excavations.

The ca. 200 m long utility conduit under the Schmidtstedter Knoten contains, besides two gas high-pressure pipelines (DN 400 to DN 600), numerous telecommunications and IT cables from various providers, and also a heavily corroded steel drinking water pipe (DN 500).

igr’s planning includes the services for the dismantling and new installation of the main drinking water pipe within the utility conduit, the construction procedures, and the underground connection to the existing water pipes outside of the utility conduit. In order to achieve this, the old drinking water pipe in the utility conduit will be replaced, using a new, innovative system, consisting of a specially coated DN 300 steel pipeline, connected with flexible, height-adjustable bearing-type coupling connectors.

With this choice of system, a long-term, corrosion resistant, and, for installation purposes, flexible solution will be put into operation.

As well as the planning of the technical processes necessary for the dismantling of the main water pipe in the utility conduit, the relocation of pipes and fittings between the complex pipeline systems outside of the conduit had to be taken into account.

The construction work began in January 2017 and is being supervised by igr.

With the implementation of this project, igr can once again demonstrate its particular skills in the specialised field of accessible underground infrastructure conduits.

Veit Bachmann