London City Airport, Dolphin 7

Scope of works

Kilnbridge were appointed as a specialist subcontractor by Topbond PLC to carry out demolition works on Dolphin 7 at London City Airport. The jetty was 156m long and 6m wide and the structure stood 1m above the water line and 6m below it. Kilnbridge were responsible for removing the concrete structure to 4m below the water line.

Kilnbridge floor sawed 780m then diamond drilled 45m of 200mm diameter holes to remove the concrete deck of Dolphin 7. A bespoke frame was manufactured for setting up the wire saw guide pulleys underwater. Kilnbridge trained a diving team on site to use and set the wire saw pulleys. Concrete cutting operatives worked closely with the divers via CCTV and a radio link during the setup operation.

The wire sawing team separated the jetty’s concrete frame structure into 52 single sections prior to the main underwater operation. All sections were cut at 4m below the water line, lifted out onto the transport barge and transported to shore through the King George V dock to the laydown and processing area.

All of these works were carried out within the King George V dock next to the London City Airport runway and terminal building. Extra care was taken care to minimise noise levels for the surrounding area and adhere to both high safety and the airport’s security standards.

Challenges / Achievements

• Underwater cutting including specialised training for divers
• Exceptional safety and security standards
• In-house design and manufacture of bespoke equipment