Crossrail C405 – Paddington Station D-Wall Demolition

Scope of works

Costain Skanska JV appointed Kilnbridge as a specialist subcontractor to reduce the levels of the station diaphragm walls using specialist techniques.

Works on the North diaphragm wall involved diamond drilling and bursting techniques whilst the South diaphragm wall involved plunge wire sawing, wire sawing and track sawing.

The South wall had to be completed in two phases using only diamond wire cutting techniques. The initial phase involved pre-cutting the 1.2m wide wall into sections varying in weight from 1.8 tonnes to 8.5 tonnes.

The second phase involved the removal of 268m of cut wall sections and a reinforced concrete guide wall up to 1.5m thick. 1,480 resin anchors were then installed and 100% tested to lift out the concrete sections.

Challenges / Achievements

• At the time, this was the largest plunge wire sawing contract undertaken worldwide (370m²).
• The total approximate weight of concrete removed was 1,650 tonnes, cut into 370 sections requiring 70 lorry movements.