Specialist contractor Ground Construction was employed by main contractor Ardmore to carry out extensive basement works for a new life science campus in the King鈥檚 Cross Knowledge Quarter.
Designed by architect Bennett Associates for developer the Reef Group, the Tribeca development will ultimately provide a million square feet of life sciences, office, retail, leisure and residential space.
Phase One was completed in July 2024 and Ardmore鈥檚 拢240m contract for Phase Two 鈥� comprising three multi-storey buildings totalling 540,000 sq ft 鈥� is due for completion in 2026.
Ground Construction is using Groundforce temporary propping equipment to support the main basement excavation for Blocks C2 and C3 as well as multiple smaller excavations within the main excavation area.
Due to the complexity of excavation, a variety of propping equipment was required, ranging from light-duty MP30 mechanical struts to the MP375, one of the largest in the Groundforce Shorco range of modular hydraulic struts, capable of supporting a load of 375 tonnes.
Groundforce Mega and Super Mega Brace waling beams were employed to transfer the lateral loads to the contiguous bore piles and steel sheet piles lining the sides of the excavations.
The excavations range in depth from about 8.5 metres in Block C2 to as much as 15 metres in the main excavation area and ranged in width from about 2.5 to 44 metres.
A total of 28 Groundforce Shorco props have been installed on the project. Nine MP250s and the one MP375 are installed within the main excavation; four MP150 are installed to support the retaining wall in the southwest excavation; 13 MP150s, two MP30s and one MP250 support the excavation for the attenuation tank and four MP250s are in the core cap excavation.
In addition to the four different sizes of prop, Groundforce Shorco also supplied extension tubes in diameters of 508mm, 610mm, 813mm and 1,220mm (the largest in its range) to ensure the optimum combination of strength, stiffness and compactness.
The largest tubes 鈥� the 1,220mm Super Tube 鈥� were used in combination with MP250 hydraulic rams to span the 44-metre width of the main excavation at two levels.
The site鈥檚 location, in a densely populated urban area, provided an additional challenge for the site team. 鈥淭he site has roads on two sides and a canal along a third,鈥� said Ground Construction temporary works director Keith O鈥機onnor. 鈥淏ut the biggest challenge has been managing the sequence of the works and the release of areas on site.鈥�
Groundforce Shorco design engineer Hussein Koussan said: 鈥淭here were a number of interacting excavations that required careful management across the site, we worked with GCL to ensure safe, efficient, and adaptable solutions. Contributing to such a landmark London development and seeing our designs perform on site has been highly rewarding.鈥�
Ground Construction and Groundforce Shorco have worked together on several previous projects and teamwork has been crucial on this site, O鈥機onnor said. 鈥淭his has been a challenging project but progress has been quite straightforward,鈥� he said.
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