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
Read more about it here (in German).
F. Hoffmann-La Roche AG
Geotechnical engineering and foundation