Walkable sewers

Sewer condition evaluation and redevelopment proposal

The StEB Köln AöR assigned ZPP with a condition evaluation, an assessment of the need for redevelopment as well as the development of a redevelopment proposal including a cost estimate for walkable sewers in Cologne-Porz.

Hereby, the ”engineer-based” condition evaluation held special meaning, as the following work steps would build upon its results. In the present case, an assessment and classification of the inspected sewers in accordance with ATV-M 149, respectively DWA-M-149-3 already ensued. The commissioned condition evaluation encompasses one more visual inspection and an assessment of the sewers (all walkable and therefore designated as large profile) under consideration of ”engineer-based” aspects. This partially leads to a diverging assessment, due to the fact that the standard evaluation catalogue of the ATV-M 149, respectively the DWA-M-149-3 originally being intended for sewers with smaller cross sections. For this reason, the damage classes that were determined with these rule books cannot be utilised for large profiles without limits.

The planning encompassed:
_8,2 km walkable sewers
_168 bearings
_Concrete, steel concrete and brickwork sewers
_Cross sections with a height between 1200 mm and 6500 mm
_A closed basin w/h 8700/6500 mm