Deep Excavation "Sparkassenhöfe" Graz, Austria

For extension of the headquarter of "Steiermärkische Sparkasse", a 14 m deep building pit was excavated in the city center of Graz. In this area, the ground consists of water-bearing fluviatile sediments with high permeability overlying fine-grained, overconsolidated Neogene sediments. The base of the excavation pit was located in the Neogene.

When developing the excavation pit support, measures for underpinning adjacent multi-storey buildings constructed in various centuries had to be designed. Furthermore, special care was required for the design of support measures at the change-over between fluviatile sediments and the Neogene.

A jet-grouting body in combination with pre-stressed multistrand anchors was used as excavation pit support, for underpinning adjacent buildings and for water-proofing. The Neogene sediments were supported using an anchored shotcrete shell.


  • Statical pre-dimensioning of measures for excavation pit support and underpinning of buildings
  • Optimisation of measures based on actual loads and constructional situation on site (thickness of jet-grouting body, location and length of anchors, thickness of shotcrete shell)
  • Structural analysis (inner and outer bearing capacity) for all relevant cross sections
  • Technical design report including results of structural analysis (verifiable calculations)
  • Geotechnical consulting for client during construction phase


Keller Grundbau Ges.m.b.H. , Söding



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