Wedge House, 32 - 40 Blackfriars Road
The piled foundations for this major hotel development comprised the following...
- A perimeter retaining wall consisting of male & female rotary bored secant piles.
A total of 139no male secant piles were drilled in diameters of 600mm, 750mm and 900mm and up to 33.05m deep below ground level. Similar quantities of 750mm diameter female secant piles were installed with depths of up to 12.05m below ground level.
Male pile reinforcement consisted of cages of 12B32 main bars for the full length of the piles. Additional B25 bars were fitted to the rebar cages complete with Ancon tapered couplers for later extending into the basement slabs. Inclinometer tubes were also attached to the rebar cages such that the movement of the secant wall could be monitored as the basement excavation took place.
- Bearing piles to support the building internally.
A total of 61no 750mm diameter piles were installed to depths of up to 27.35m below ground level. Pile reinforcement consisted of cages of 12B25 main bars again provided for the full length of the piles.
All piles were installed through Made ground, Alluvium, River Terrace Deposits and terminated in the London Clay Formation that was encountered at a depth of 7.0m below ground level.
As the excavation progresses the excellent line of the secant wall can be seen and demonstrates our ability to install secant wall piles to the strict tolerances required.
The secant wall required extensive temporary propping until the structural slabs were in place.