HYDRAULIC EXPANSION WITH DN 1400
STRAIGHTENING A BEND
Hans-Joachim Risto, Steinzeug-Keramo GmbH, Lutz Klutke, Ingenieurbüro Klutke GmbH, Jürgen Kregel, Berliner Wasserbetriebe (BWB), Ulrike Schulze, Leitungs- und Tiefbaugesellschaft Seelow mbH
“Berlin-Friedenau, Backflow Construction Segment 7, Handjerystrasse” – this is the name of a project commissioned by Berliner Wasserbetriebe (BWB, Berlin’s Municipal Water Utilities) to Ingenieurbüro Klutke GmbH, a company of construction consultants. A particularly challenging aspect of this project is the hydraulic expansion of an existing combined wastewater sewer with DN 1400 vitrified-clay pipes at the Friedrich-Wilhelm-Platz road junction.
Although this project doesn’t appear to be out of the ordinary at a first glance, it was anything but normal when it came to its planning. Beneath the nearby Friedrich-Wilhelm-Platz, an old sewer, egg-shaped in cross-section, that was presumably originally laid to follow the bend in the road above, had to be regenerated and aligned with the modern-day road arrangement. At the same time, it would be necessary to keep the old sewer in operation throughout the entire construction project. Thanks to an external bypass route (siphon-action system), with two DN 600 systems running parallel to the construction zone, the company responsible for the construction, Leitungs- und Tiefbaugesellschaft Seelow mbH, overcame the many difficulties and challenges to successfully complete the project.
Adverse conditions professionally mastered
According to BWB Rule Sheet 11, these not particularly favorable subsoil conditions specify a special bed for the pipes: “When adverse subsoil conditions are present, then independent of the static design a concrete embedment must be constructed to ensure that wastewater sewers of sizes ≥ DN 1200 can be safely laid.” This standard has proven itself in Berlin. Sewers with diameters of DN 1200 or larger are by no means an exception in major cities the size of Berlin, and safety and a long service life are naturally also decisive factors. The manholes in this sewer are in all cases individually constructed modules, fitted with manhole connecting sockets made of vitrified clay.
But even “run-of-the-mill” construction activities of this kind have their own special aspects: the spatial conditions between the main road and the residential buildings were very constricted, meaning that a great deal of effort had to be invested in the organization and planning of the necessary lifting and hoisting facilities for the pipes and the manholes.
“Poured in concrete” for generations to come
But it’s not just the concrete embedment support that ensures the safety and long service life of the sewer. The chemical, physical, and hydraulic properties of the material used to make the pipes, vitrified clay, and the high quality of the construction work performed by a qualified contractor all combine to guarantee a robust and efficient wastewater-disposal installation that will last for many generations to come. What’s more, it makes a major contribution to relieving the burden on the environment – an especially valuable aspect for a city with a population of millions, such as Berlin.
Client: Berliner Wasserbetriebe (BWB) | Planning: Ingenieurbüro Klutke GmbH, Berlin | Construction: Leitungs- und Tiefbaugesellschaft Seelow mbH, Ahrensfelde | Construction-materials supplier: TFG Luhn & Ackermann KG, Teltow