Repair of the Oxfordstrasse underground parking garage

As part of numerous on-site inspections by the Materials Testing Institute (MPVA) and ZÜBLIN Bauwerkerhaltung, extensive concrete technology tests were carried out at precisely selected points. In addition, targeted component openings were made to check the current corrosion condition of the reinforcement. This revealed advanced corrosion and, in some cases, considerable material loss at all of the column positions examined.

Due to the heavy contamination of the concrete with chlorides, particularly in the area of the columns, ZÜBLIN Structural Maintenance was commissioned with the extensive repair of the underground car park. As it was not possible to increase the concrete cover as a renovation measure, it was decided to completely remove the 154 affected columns and replace them with new, more compact columns.

Identification of alternative refurbishment measures

The results of a special feasibility study revealed a differentiated approach for the repair and strengthening of the underground car park. Existing columns will be removed using a temporary support structure and replaced with new, narrower reinforced concrete columns. Concrete repairs will be carried out on affected concrete and wall surfaces. Damaged columns that cannot be dismantled and rebuilt due to excessive loads caused by buildings above the underground car park will also be overhauled with appropriate concrete repairs.

Measures to date:

• Demolition of approx. 8,000^m2 of mastic asphalt
• Support of the 56 support strands by means of steel construction and hydraulic presses
• Removal and new concreting of the 154 damaged reinforced concrete columns with prefabricated reinforcement cages
• Concrete restoration on all components
• Installation of approx. 11,000^{m2 PRM screed}
• Coating of approx. 11,000^m2 including marking of the floor surfaces