The project is for the construction of a new underground multi-purpose hall at Uranienborg, under Nordahl Rolfsens plass. The entire building, apart from the entrance area and ventilation tower will be located below ground. The gross area is 2 370 m². The ground is rock.

Nordahl Rolfsens plass is located between Uranienborg School and Uranienborg Church.

Nordahl Rolfsens plass shall appear as almost unchanged after the work has been completed. Preservation interests have guided the conditions for the location and form of the building. The trees along the square shall be kept.

The framework permission has been received.

The contracting authority wishes to emphasise three main challenges in the project:

— The planning and execution of safe blasting works.

— Extensive mass removal/transport to and from a densely built-up city/urban areas.

— Engineering design and production of waterproof structures.