Piled foundation scheme for a 700-bed, 21-storey student accommodation development.
McAleer & Rushe engaged Cannon Piling to under take the piled foundation scheme for a 700-bed,
21-storey student accommodation development at Crutched Friars, Fenchurch Street, in the financial district of London. The project was carried out in two phases, the duration for the first phase was seven weeks, followed by an eight-week second phase. The project required the installation of 500mm diameter CFA contiguous bored piles and 600mm & 750mm diameter rotary bored buttress, bearing, and crane base piles.
Cannon Piling was engaged at an early stage to collaborate with the client and optimise the foundation design. The initial CFA scheme was value-engineered to a predominantly rotary bored solution, which provided multiple advantages. The change in technique enabled the use of a smaller rotary bored rig, which could be deployed on smaller platforms at varying elevations. This approach also improved accessibility, allowing buttress piles to be installed between existing basement props without significant structural modifications. The contiguous bored piled wall was designed to navigate around existing piles, ensuring structural integrity while minimising disruptions.
By re-engineering the original CFA solution into a rotary bored solution, Cannon Piling achieved seamless integration with existing structures. Buttress piles were threaded around existing basement props with minimal temporary removal, maintaining project efficiency. The use of a smaller and lighter rotary bored rig also reduced pile mat thickness requirements, lowering material costs and improving project sustainability.
The 65 Crutched Friars project was particularly challenging due to its location within London’s
financial district and the technical complexities involved. Effective pre-planning and sequencing
were crucial to its success. The first phase focused on installing buttress piles within the existing basement at multiple levels between existing props. This phase also included the installation of crane base piles to facilitate early erection of the tower crane for the next phase. The second phase involved the installation of a contiguous piled wall, carefully threaded around existing piles to enable basement extension, alongside the installation of 750mm diameter bearing piles up to 36.5m deep.
Cannon Piling worked closely with the client and design team from the pre-construction phase
through to completion. This proactive collaboration ensured that the project was delivered on time through careful planning and phased execution, on budget through value engineering and optimised construction methods, and to a high standard with stringent quality control measures ensuring structural integrity and durability.
The 65 Crutched Friars project exemplifies Cannon Piling’s ability to deliver complex foundation solutions in dense urban environments. Through innovative design, meticulous planning, and close client collaboration, the project was completed efficiently while overcoming significant logistical and technical challenges. This case study highlights the effectiveness of early contractor involvement and value engineering in achieving outstanding project outcomes.
Material Stats |
Concrete Volume – 3245m3 - 369.78tCO2e(materials only) |
Steel weight – 199.591 Ton – 211.48 tCO2e(materials only) |
Carbon burnt - 868.4 tCO2e (materials and fuel total) |
Number of rigs – 3, 1no. 60ton crawler crane -287.144 tCO2e (fuel) |
