With Liverpool Street Station less than a 5-minute walk and connectivity with four underground lines, national rail links and Crossrail, the development is destined to be extremely popular.
Principal Tower expresses the relationship between the creative, formerly industrial east end and Britain’s financial centre, appearing as three slim volumes.
Where the tower addresses the residential neighbourhood of Shoreditch, it appears lower from ground level, while from the west it reflects the highrise nature of the City. A central volume
rises up between the two to provide an elegant marker on the skyline.
BAUER Technologies Ltd was awarded the £4.86m foundations contract by Brookfield Multiplex Construction Europe on behalf of their Client, a joint venture
between Brookfield Office Properties and Concord Pacific. Specifically, Bauer was appointed to install the piled foundations and secant walls for the Principal Tower, which was particularly
challenging. In particular Bauer was required to work under restricted space conditions, next to a live railway, around strict load restriction zones and
in amongst other trades on site. Some 81no., 1500mm bored piles, up to 55m deep were installed, including 8no. permanent casings with bitumen coating, 14no. large section plunge
columns, and 10no. king posts. 32no. 880mm bearing piles, up to 33m deep, were also installed as well as 214no. 880mm secant wall piles (150 linear meters), up to 33m deep including
24no. king posts.
Despite the challenging works constraints particular to the project, Bauer was able to complete the piling works on time and without any lost-time or accidents. Most importantly, the
implemented risk assessments and associated mitigation measures allowed the piling team to install all piles without interruption to the live railway directly adjacent. Bauer, as a
leading piling equipment manufacturer, was able to draw on its specialist foundations contractor knowledge to carry out project-specific plant modifications, which allowed a BG40
piling rig to install heavy duty pile casings of up to 2000mm diameter, whilst standing on sensitive temporary works structures with strict load restrictions.
Bauer’s equipment knowledge also allowed the site team to master a number of technical issues; the first being its response to the challenging design of a large diameter secant wall
with piles at very close spacing. Bauer addressed this issue by using it’s newly developed ‘On-top Reaming Tool’, which allows time-efficient widening of the uncased pile shaft to the outer
diameter of the temporary casing. The second technical issue - the installation of heavy duty plunge column piles as support for the future top down slab - Bauer designed and manufactured a
hydraulic, laser guided frame, which allowed all plunge columns to be installed successfully in bentonite filled bores, well within agreed tolerances.
In order to reduce loading of the adjacent fragile Network Rail brick arch tunnels, Bauer used their experience from previous projects to successfully
install permanent, bitumen coated liners just millimetres from the existing structure. Working in an area with intensive historic industrial and residential
use, the Bauer piling rigs also removed numerous buried obstructions, such as pad foundations and bearing piles.
Notably, in a second phase of the works, Bauer used a 350 tonne mobile crane to safely lift its BG30 piling rig into the partially excavated secant wall
box. This allowed the remaining bearing piles to be installed after successful completion of archaeological excavation works by the Museum of London.
Speaking about the project and the performance of Bauer on-site Gustav Jahnert, Project Manager at BAUER Technologies Limited said: “Our high standards in Health & Safety, as well
as our normal performance orientated planning, allowed us to complete this complex project ahead of programme. Bauer’s high quality standards allowed the follow on contractors to continue with excavation
of secant walls and installation of top down and intermediate slabs early without having to deal with remedial work related delays.”
||Brookfield Office Properties and Concord Pacific
||Brookfield Multiplex Construction Europe
||BAUER Technologies Limited
||January 2016 - August 2016
||- BG40 and BG30 piling rig; 350 tonne
mobile crane; On-top Reaming Tool,
hydraulic plunge column frame
|Bauer's Scope of Works:
||- 81no., 2000/1500mm bored piles, up to 55m deep
- 8no. permanent casings with bitumen coating
- 14no. heavy plunge columns
- 10no. heavy king posts
- 32no. 880mm bearing piles, up to 33m deep
- 214no. 880mm secant wall piles (150 linear meters), up to 33m deep including 24no. king posts