Building Pit Roche Building 1 Basel, Switzerland

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1 Building Pit Roche Building 1 Basel, Switzerland Implenia Spezialtiefbau GmbH Infrastructure - Central Branch Mannheim Office Diffenéstraße 14 D Mannheim GERMANY T F mannheim.spezialtiefbau@implenia.com

2 Contract Value (net): 13.4 million CHF (11.1 million Euro) Construction Period: 02/ /2012 Client: F. Hoffmann - La Roche AG, Basel Services: Production of a building pit, foundation of a high-rise, dewatering Production of the foundation piles D=120 cm

3 The company F. Hoffmann-La Roche builds a new group headquarters at its Basel group head office. After completion in 2015 "Building 1" at 41 storeys and 175 m high will be the tallest building in Switzerland and will offer space for approx. 2,000 jobs. The "Baugrube Roche Bau 1" joint venture, consisting of Implenia Spezialtiefbau GmbH and Schleith GmbH, was contracted to produce a turnkey building pit as well as the extensive foundation works. The j.v. exhibits a vertical split, the full foundation engineering is performed by Bilfinger Spezialtiefbau GmbH, which also has technical and commercial direction. The earthworks required to produce the building pit were performed by the company Schleith. In the run-up to the building measure comprehensive proof loads and suitability tests were conducted on large bored piles and installation anchors, in order to verify the soil values or respectively optimize the calculation bases. The building pit has a depth of max m and is enclosed by an up to 4-layer rear-anchored secant bored pile wall D=120 cm. Drilling depth of the installation piles is up to m. The rear-anchoring of the building pit wall consists of 530 pieces grouted anchors having drilled lengths of up to 33.0 m and up to 9 strands as well as test forces of up to 1,200 kn. 80 % of the installation anchors will be stripped back again as the structural work progresses. For this purpose Bilfinger Spezialtiefbau uses the Swiss-patented system CONA-Therm with thermal induction coil. Conducting dynamic pile proof load View of the drilled pile wall with anchor tensioning works

4 The foundation of the structure consists of 143 large bored piles D= 120 cm with pile lengths up to 24 m. Owing to the extreme building pit depth combined with the constricted space the foundation piles were executed from a pre-excavation level using an empty drill hole of approx m. The whole construction measure is equipped with a comprehensive measuring and monitoring concept, making it possible to maintain continuous production with laboratory installations in the directly adjacent existing buildings. In order to limit subsidence and inclines on the directly neighbouring high-rise, the high-rise was underpinned with a sleeve pipe injection. Both temporary and residual dewatering is led via automatic turbidity and ph value measurement, under compliance with all defined limits, the accumulating water is automatically conducted into the outlet into the Rhine, otherwise into the city sewers. In order to achieve ground water flow in the final state, on the northern and southern side of the building pit (flow direction of the ground water) 4 pc. each horizontal filter wells are produced through the installation wall. The ground water is extracted via these wells in the north, conducted through the completed structure and returned to the subsoil in the south. View into building pit Final depth

5 Quantities: 4 pieces dynamic pile proof loads 2 pieces static pile proof load with Osterberg Cells 9 pieces suitability checks on strand anchors 246 pieces / 5,706 rising metres piles for secant bored pile wall D=120 cm, drilling depth down to 32.5 m 143 pieces / 4,423 rising metres foundation piles D=120 cm, drilling depth down to m, empty drill hole ~10m 530 pieces / 13,000 running metres grouted anchors up to 9 strands, length up to 33.0 m, test forces 900 / 1,200 kn, 80 % strippable anchors 10 pieces / 120 m GEWI piles D=63.5 mm 400 m³ sleeve pipe injection for subsidence and incline limitation in a neighbouring existing high-rise 8 pieces pile force gauges for permanent gauging Expanded measuring installations for combined pile-slab foundation such as pore water pressure indicator, bearing-pressure indicator, drill holes to determine water level, inclinometer, sliding deformeter Temporary dewatering with turbidity measurement and neutralization plus residual dewatering during structural work using horizontal filter wells for ground water flow in the final state 15,000 m³ demolition remaining existing buildings 48,000 m³ building pit excavation, depth down to m 125,000 t removal demolition and excavation View into the building pit chipping-off works