Slide 1: Design, construction and performance of a basement Pali Radice contiguous minipiled retaining wall
Design, construction and performance of a basement Pali Radice contiguous minipiled retaining wall beneath at The Berkeley Hotel, Knightsbridge, London Piling 2020 Conference F. Pero (Presenting Author) S. Vaughan K. Xu D. Schutt keller.com
Slide 2: The Berkeley Hotel extension
The Berkeley Hotel extension 2 2
Slide 3: Existing diaphragm wall
Existing diaphragm wall • Base of the D-wall from coring ≈ -3.7m OD. • New basement formation level at -8.4m OD (5.0m to 5.5m below the base of the wall • Excavation depth around 20m from ground level at 11.5m OD. 3
Slide 4: Excavation support proposals
Excavation support proposals Initial proposal • Traditional underpin and propping the D-wall during excavation • The D-wall was supporting loads. The Hotel was sensitive to vertical settlement of the D-wall • Underpinning delaying the programme • Two under-reamed piles adjacent to the wall Alternati
Slide 5: Pali Radice system
Pali Radice system • Pali Radice (Root Piles) technique were introduced by Dr F. Lizzi in the 1950’s in Italy • Pali Radice can be installed through and bonded to existing structures • The system can bore directly through materials such as reinforced concrete, timber, cast- iron, granite, etc., obvi
Slide 6: Pali Radice system
Pali Radice system } KELLER
Slide 7: Ground conditions
Ground conditions • Made ground overlying in turn Langley Silt, River Terrace Deposits and the London Clay Formation • Piling commencement level 1.5m above the London Clay Formation 7
Slide 8: Construction Sequence
Construction Sequence • Install plunged at piling platform level (Street level) • Excavate to underside of B1 slab level at and cast B1 slab • Excavate to underside of B2 slab level at +1.155m OD • Install Guide wall for Pali-Radice piles and cast part of B2 • Install Pali-Radice piles from 1.455m O
Slide 9: Soil structure interaction
Soil structure interaction A 3D finite element model was developed to capture the staged construction of the proposed basement substructure and underpinning, with a view to incorporate the complex constraints and assess: • SLS and ULS-DA1 C1 and C2 propping forces. Partial factors were applied to th
Slide 10: Movement monitoring
Movement monitoring Monitoring survey points for the Pali Radice wall were installed at • T1 temporary prop level • B3 slab level • T2 temporary prop level • Displacement of the wall were recorded during excavation between September and November 2019. 10
Slide 11: Lateral displacement of the Pali Radice wall
Lateral displacement of the Pali Radice wall T1 level movement • Recorded average lateral movement ranges between 1.2mm and 3mm during excavation • The lateral displacement of contiguous wall and the excavated depth calculated from T1 was only 0.092% indicating that a high lateral support stiffness
Slide 12: KELLER
} KELLER
Slide 13: Questions ?
Questions ?