DESCRIPTION OF THE PROJECT:

The Seitz Group built a new Porsche Centre in Kempten (Allgäu), Bühl industrial estate. In addition to the actual Porsche Centre with 1,100 m² of exhibition space and workshop, a central warehouse and the new administration for the entire Seitz Group with a total of 90 workplaces were also built on the approximately 12,000 m² site. The ground-breaking ceremony took place in July 2013 and the centre was completed in spring 2014.

On behalf of the city of Kempten, ICP Altusried initially carried out preliminary soil investigations, which were then specified by a detailed investigation adapted to the project after the draft planning. A total of 35 exploratory drillings were carried out, as well as numerous test trenches during construction.

The subsoil in the construction area consists of Quaternary-glacial boulder clay of stiff-semi-solid consistency, which is overlain by soft to mushy, clayey-silty basin deposits, weathered clay and partially peat soil up to 7 m thick. Initially, a mass assessment was carried out for the city of Kempten for the variant of a full soil replacement down to the load-bearing subsoil; as a result, this variant was not pursued further due to the immense mass movements as uneconomical. An alternative concept was developed based on soil improvement.

Geiger Hoch- und Tiefbau, Oberstdorf, carried out the ground improvement. The specification for the subsoil improvement measure was to produce a load-bearing subsoil for the Porsche Centre, the administration building and the central warehouse as well as for the traffic routes over an area of around 11,500 m². Under the Porsche Centre, 3,500 metres of vibrating stop logs were constructed, and in the area of the other buildings and the traffic areas, the existing soil was stabilised by milling in hydraulic binder or partial soil replacement with gravel/crushed stone was carried out.

Services performed by ICP:

• 2011: Preliminary investigation by means of trenching, small pile driving and soil mechanics field/laboratory tests, subsoil assessment, determination and massing of soil replacement.
  Client: City of Kempten (Allgäu), Office for Civil Engineering and Traffic, Kronenstraße 8, 87435 Kempten, Germany
• 2012 - 2014: Detailed investigation by means of further small pile driving boreholes and soil mechanics field/laboratory tests, preparation of the geotechnical report with alternative foundation concept on soil improvement, consulting during construction.
  Client: Walter Seitz GmbH & Co. KG, Immenstädter Straße 81, 87435 Kempten, Germany
• 2013 - 2014: Suitability tests and compaction proofs in the course of the soil improvement works.
  Client: Geiger Hoch- und Tiefbau, Wilhelm-Geiger-Straße 1, 87561 Oberstdorf, Germany