At the NSTT (the Dutch industry association for trenchless technology) conference on 8 November 2018, the renovation of the main sewer in Arnhem was announced winner of the No-Dig Award 2018 and winner of the Public Award. The prize, which is awarded annually, was awarded to this project because it has succeeded in achieving the best possible solution by using various trenchless technologies and whilst keeping disruption to a minimum. Witteveen+Bos has been closely involved in the main sewer project for many years in its capacity as an in-house advisor for the Municipality of Arnhem.

The main sewer is 1 kilometre long and approximately 150 years old. It runs straight through Arnhem city centre and regulates the underground drainage of rainwater and waste water. Its shape, size and structure make it a one-of-a-kind in the Netherlands. The structure consists of a 3-layer brick arch on two non-reinforced concrete strips with a concrete channel in between. The fact that no streets could be demolished at any point during the preparation and execution of the project made this a particularly exciting challenge. A great deal of attention was also paid to ensuring the safety of the operational staff and the surrounding area.

Cooperation with Witteveen+Bos
Over the past 6 years Witteveen+Bos has carried out a wide range of studies and provided a variety of services, from variation studies and advanced 3D EEM stability calculations to drawing up the contract and supervising the tender. Witteveen+Bos also carried out inspection activities and advised on renovation methods. Witteveen+Bos project manager, Jeroen de Leeuw: ‘We would like to congratulate the Municipality of Arnhem and the construction consortium, and we are also very proud that this project has won a number of awards. They are a great testament to the effort put in by the entire team to strive for an integrated solution, minimal disruption above ground and the application of special underground technologies.’

Implementation
Contractor G. van der Ven and Kumpen Renovatietechnieken are currently in full swing working on phase 1 (550 m) of the project. The preparation of phase 2 (length approximately 550 m) is scheduled to start soon. The entire project should be completed in 2020.

+ ruud.hampsink@witteveenbos.com