Sewage plant Großlappen in Munich
In spring 2003, Area South of Wayss & Freytag Ingenieurbau AG started on the construction of four new septic tanks for the “Gut Großlappen” sewage treatment plant in Munich. In the plant that was completed in spring 2007 and is connected to the existing sewage treatment plant by a 155 m long installation channel, the mud incurred during wastewater treatment is collected and stabilized by digestion. The biogas generated during this process provides the heat required by the sewage treatment plant.
The four cone-shaped tanks have a volume of 14,500 m³ each and are 45 m high. The wall thickness of the lower part of the cone-shaped tanks is 70 cm at the bottom and 50 cm in the upper part, which has a gradient of 70. The load transfer is carried out through a ring beam on large bored piles placed in the equatorial plane. Geometry and loads required threefold prestressing: (a) ring prestressing to take horizontal load components, (a) meridian prestressing with loop anchoring to take lifting forces and (a) conic prestressing to fix the lower part of the cone to the ring beam.
The tanks were built to be watertight. Besides, for the prestressing an extremely high non-prestressed reinforcement had been required, so that the lower cone had to be carried out in self-compacting concrete. The appropriate concrete mixtures were developed and monitored by the W&F in-house concrete laboratory in Langen.
Further details:
- 2,400 m³ standard concrete C35/45
- 1,300 m³ self-compacting concrete C35/45
- 800 t reinforcing steel
- 160 t prestressing steel
- 12,500 m² formwork