No bog-standard stability analysis for a wide profile in Essen, Germany

Jul 23, 2009

Last year, S & P Consult was tasked by Stadtwerke Essen with an extended assessment and evaluation of the condition of the combined sewer "Graitengraben" in Altenessen. The section to be inspected was about 750 m long, with four different cross sections and three special sections. In addition to the extended evaluation of the condition, we paid special attention to the appraisal of the stability analysis of the sewer section.

The different types of profiles posed a challenge to us. A total of eight different cross section types had to be assessed. The profiles consisted of an in-cast concrete base and in-cast concrete side walls with ceilings made of reinforced concrete or pre-cast segments, in-cast concrete base elements with masonry vaults or natural stone elements with rolled beams-in-concrete-ceilings, and required complex analyses of the material. In addition to the common core bores a sampling of the steel reinforcements also turned out to be necessary for a belated assessment of the steel grade. We determined the characteristic values of the subsoil that were required for the static calculations by means of an inspection scheme that was set up and attended by ourselves using heavy dynamic probing, small-scale dynamic drilling, and the soil characteristic values that were identified under laboratory conditions. Only that way it was possible to capture the non-linear interdependency between building and soil exactly by means of aligned FEM programs. This task required the construction of most different FEM models and a great deal of experience in this field.

In fact, the result of the stability analysis allowed a different view that met both the complex task and the very different facets of the sewer. Not every cross-sectional type could be statistically proven. This fact produces evidence that a very individual stability analysis is mandatory especially in the case of wide profiles. Only that way can firm assumptions be gained as a basis for a future rehabilitation concept. You will find the inspection scheme in full on our website in the special field of planning.

S & P Consult GmbH
Konrad-Zuse-Str. 6
44801 Bochum
Tel: ++49 234 5167 0
Fax: ++49 234 5167 109

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S & P Consult GmbH

44801 Bochum


++49 234 5167 0


++49 234 5167 109



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