THE SCHEME
Bachy Soletanche was appointed by Mace Construct to deliver the foundation works for the £140 million expansion of Pier 6 at London Gatwick Airport. Once complete, the mid-airfield development will introduce eight new aircraft gates adjacent to the runway, enabling an additional 7.5 million passengers to board and disembark directly from aircraft each year. This will eliminate the need to transport over 500,000 passengers to remote stands, removing an estimated 12,000 annual bus journeys.
DESIGN AND PLANNING
Bachy Soletanche designed the piles and the piling platform, proposing a number of value-engineered solutions that significantly reduced both the length and diameter of the piles without compromising performance. This resulted in a 12% reduction in concrete and 30% reduction in steel reinforcement.
In addition to this, Bachy Soletanche’s in-house designers optimised the piling platform by developing a gradient-based design, which minimised excavation depth and material use.
During the planning phase, the team identified key project risks and proposed mitigation strategies to support the safe and efficient delivery of works within a live airside environment.
PILING OPERATIONS
P.J. Hegarty & Sons installed the piling platform under Bachy Soletanche’s supervision. Following this, Bachy Soletanche installed 215 continuous flight auger (CFA) piles using a Liebherr LB24 piling rig, with diameters ranging from 600mm to 750mm and depths of up to 9m.
The site comprised three distinct platform levels, each requiring a mix of pile sizes. Bachy Soletanche secured approval from the rig manufacturer to ensure the auger could remain attached when moving between levels.
While access to certain piles was temporarily restricted, the team adapted the sequencing to maintain progress. Through coordinated planning and flexible delivery, all piling was completed successfully to the required standards.
OPERATIONAL EXCELLENCE IN A LIVE AIRSIDE ENVIRONMENT
Working in a live airside environment demanded extensive planning and careful coordination. Every operative and vehicle required an airside pass, with permanent staff undergoing a detailed vetting process. Bachy Soletanche needed to obtain weekly permits, such as a Permit to Dig, from Mace Construct, as well as a Crane On-Airport permit from London Gatwick, specifying crane location and purpose.
Bachy Soletanche procured plant specifically to comply with the site’s strict 27m height restriction. In accordance with airside safety protocols, the team also used an integrated real-time activation system to notify airside control of all crane operations at the start and end of each shift.
To eliminate the need for hot works, and therefore the risk of fire, the team used hydraulic rebar cutters to trim steel reinforcement. Along with this, a policy was enforced on site to prevent debris-related incidents, with an additional section added to the Risk Assessment Method Statement to specifically address and manage this risk. Coordination with Mace Construct, other contractors and the airport operator was vital throughout.
DRIVING DOWN CARBON
The wider Pier 6 expansion is on course to achieve a BREEAM rating of “Excellent”, with a projected 52% reduction in embodied carbon against the original design. Bachy Soletanche supported this outcome through design optimisation and sustainable construction practices.
The client specified a minimum 30% ground granulated blast-furnace slag (GGBS) content in the concrete mix. Bachy Soletanche exceeded this by using a mix with 67% GGBS, resulting in a saving of approximately 40 tonnes of CO₂e.
Alongside this, the team used an excavator instead of a crane to install reinforcement cages, which reduced fuel use by around 1,500 litres, saving an additional 4.8 tonnes of CO₂e. All ancillary materials and equipment were sourced from local suppliers with airside experience, further reducing the project’s environmental footprint.
