Roche pRed

As part of the modernization of its historic site in Basel, F. Hoffmann-La Roche Ltd is erecting pRed, a new research facility composed of 4 buildings, whereof 2 lab-buildings will be up to 115 m high.

For the construction of the new facility an existing diaphragm wall of the 1970s was fully reactivated, which resulted in substantial cost- and time-savings. The existing diaphragm wall was secured with 5 anchor layers, built with 12 anchor drilling rigs working in parallel. Challenging were the restricted space conditions with limited height of less than 2.3 m as well as the drilling with up to 12 m high groundwater pressure in the highly permeable subsoil. After completion of the anchor works the excavation pit of 22 m depth could be executed parallel to the demolition of the basement of the existing building.

The foundation consists of a combined piled raft foundation (CPRF) to count for the extreme load eccentricity on the basement and to reduce the settlements of the new facility. The bored piles with a diameter of 1.20 m were constructed from the excavation base. A high pile concrete quality of C35/45 was used in areas of high stress after appropriate suitability testing.The foundation was computed with 2 coupled finite element models (structural and geotechnical models). These models have been iteratively and automatically matched with a self-written procedure. The input parameters of the 3D-FE-models were calibrated according to the long-term measurement results of the neighboring high-rise Building 1 - also founded on a CPRF. In addition, several static and dynamic pile tests of Building 1, which were carried out up to failure, were used for a better calibration of the ground parameters.

Services provided by Gruner Ltd's Geotechnical Engineering Department and Gruner Lüem AG comprise:

• Planning for the following phases: preliminary design, basic design, tendering, detail design
• Excavation pit, combined piled raft foundation, ramp, demolition/deconstruction,
• Deformation forecasts and monitoring for the excavation pit, foundation and neighboring buildings due to the excavation of the pit, dewatering, construction of piles and anchors, building construction
• Construction management for the excavation pit, foundation, ramp and demolition

Services provided by Gruner Ltd's Structural Maintenance Department comprise:

• Crack-monitoring, preservation of evidence, monitoring of noise and vibrations

Publications regarding this project: 

• Westermann, J.; Pitteloud, L.; Meier, J. (2020): Automatisierungsaspekte bei der Planung von Baugrube und Gründung eines Forschungszentrums. Bautechnik, Vol: 97, No: 12, S. 878-885. pdf
• Westermann, K.; Grasso, P.; Pitteloud, L. (2020): Reaktivierung einer 45 Jahre alten Schlitzwand als Baugrubensicherung. Kolloquium Bauen in Boden und Fels, Vol: 12, No:1, S. 307-317. pdf link
• Pitteloud, L.; Meier, J. (2017): Statische und dynamische Versuche an Bohrpfählen in der Molasse im Raum Basel. Burgdorfer Geotechniktag 2017 - Beobachtungsmethode und Monitoring in der Geotechnik, Berner Fachhochschule, Burgdorf, 19.01.2017. pdf

Further publications: https://www.gruner.ch/en/Discover/scientific-articles-and-publications-geotechnics

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