Sewer relocation Weilburger Straße / Kleyerstraße

CLIENT The Stadtentwässerung Frankfurt am Main.
THE SERVICES
    •        Performance Phases according to HOAI (German Official Scale of Fees for Services by Architects and Engineers): 2 - 9:
    •        Preliminary design.
    •        Design for approval by authorities.
    •        Detailed design.
    •        Preparation of tendering.
    •        Assistance in tendering and contracting.
    •        Construction management.
    •        Object management and documentation.
    •        Traffic management plan.
    •        Local construction supervision.

The Stadtentwässerung Frankfurt am Main (the municipal enterprise of the City of Frankfurt/Main responsible for waste water collection and treatment) intends to put out of service one brickwork sewer egg-shaped profile DN 850/1500 mm for explosion protection reasons, since the mentioned sewer is partially superstructed by the buildings of Deutsche Bahn (the German Railway) and an industrial plant.
However, the house connection pipes, existing in this section, are supposed to remain in operation.
Kocks Consult GmbH was assigned by the Stadtentwässerung Frankfurt am Main to carry out design and construction supervision services.
the services
A prerequisite for the shutting down of the sewer section was the determination of a new route providing a connection to a parallel sewer in the street Kleyerstraße in the future. After having evaluated the preliminary design, it was decided to lay the new sewer along the existing railroad embankment.
Due to high groundwater levels, very permeable subsoil and complicated traffic situation, the construction of the sewer occured by means of steered pipe jacking. Between the two sewers, which were supposed to be connected, there was only a minimal gradient (0.035 %). For hydraulic reasons it was decided that an circular pipe DN 1400 with an egg-shaped inliner-pipe DN 1200/800 mm shall be jacked.
Glass fibre reinforced plastic (GRP) was proven to be the appropriate material. The existing house and gully connections of the sewer section to be shut down were connected with a GRP-Inline-Pipe DN 250. Thus, the flow direction was turned around and the waste water was discharged toward the new egg-shaped pipe DN 1200/800 mm. After the installation of three inspection shafts, the free space between the UP-GF-Inline-Pipe and the existing old sewer was filled in.
The overall measure was completed by the extension of an in-situ concrete box profile (W/H = 3500/2500 mm) toward the connection structure at the crossways Kleyerstraße/Ackermannstraße.
For the design of the measure, difficult conditions, especially due to high groundwater levels and groundwater contamination had to be taken into account. Therefore, an individual pit lining and dewatering concept was elaborated for every construction pit:
    •        3 nos. of construction pits strengthened with shotcrete and with temporary groundwater lowering.
    •        3 nos. of construction pits with pressed sheet pile walls and jet grouting sealing beds.
    •        A construction pit with pressed sheet pile walls.
       
Project period:
Design 2001 - 2004.
Construction 2005 - 2006.