22 Bishopsgate

Scope of works

Kilnbridge were contracted by Keltbray to remove the partially constructed core and other works to enable the new development of 22 Bishopsgate. Due to the sensitive location of the site, conventional demolition could not be utilised so all removal was carried out via a cut and lift methodology.

The works were comprised of three main elements:

• Core removal: Kilnbridge were responsible for the removal of 12 levels of the core from Level 9 to B3. The core measured 16m x 16m on plan with 500mm thick perimeter walls, 300mm thick internal walls and slabs on each level. Kilnbridge cut the entire structure into sections to facilitate lifting; in total, 2,400m³ of concrete was cut into approximately 1,000 sections.
• Suspended slab removal: In total, Kilnbridge removed approximately 2,000m² of suspended slab on the ground level and Levels B1 and B2. The slabs varied from 300mm to 600mm thick and were cut into sections weighing up to 8 tonnes using wire, track and floor saws. Kilnbridge also designed and installed the temporary works and crash decks to facilitate their removal.
• Basement slab removal: Kilnbridge plunged, wire sawed and stitch drilled the perimeter of 1,100m² of the 2.2m deep slab and broke it out using robotic demolition machines to facilitate piling.

Challenges / Achievements

• All temporary works and crash decks to facilitate the demolition were designed and installed in-house
• Many different techniques were utilised to limit noise, dust and vibration in a sensitive city location