Crossrail Time-Lapse Film Features FP McCann Precast Segmental Shaft Linings

FP McCann's precast concrete segmental shaft linings feature in a time-lapse film produced by Crossrail demonstrating how main contractor Costain Skanska Joint Venture (CSJV) builds a 4.5 metre diameter compensation grout shaft using a "top down" caisson method of construction, whereby the shaft is constructed from the surface and pushed down into place.

The video (link below) shows a steel cutting edge placed at ground level and the first concrete ring is then installed on top of the cutting edge.  The shaft is forced into the ground under the weight of each ring in combination with the pushing force of the hydraulic jacks.  The hydraulic rams are used to vertically sink the shaft one metre at a time, allowing another concrete ring to be placed on top and the process is repeated. 




FP McCann supplied a total of 525 precast concrete segments for five 4.5 metre grout shafts over a period of 3 months to Joseph Gallagher Construction Ltd, shaft contractor to the CSJV. Commenting on the work, Howard Lloyd shafts and tunnels contracts manager for FP McCann said, "We worked very closely with the CSJV design team and installation contractor, Joseph Gallagher on the Bond Street jobs. Because of restrictions at all the sites, we operated a just-in-time delivery programme which ran very smoothly throughout"

A time-lapse video of the shaft building process can be viewed by clicking on the below link:

http://www.crossrail.co.uk/route/stations/bond-street/bond-street-station-news/construction-a-grout-shaft-for-bond-street-eastern-ticket-hall#contentFP

This week, FP McCann is due to complete a 105 segment order to Barhale Construction for another 4.5m grout shaft 15 metres deep in Sheraton Street, part of the Tottenham Court Road Station development. This shaft features the newly introduced back-bolted segmental linings to facilitate safer caisson construction. This will be the second shaft supplied on the Tottenham Court Road scheme; the first was a similar 105 shaft linings order from Galldris Construction working for main contractor, Morgan Sindall.

The images below show the corbel ring sections which will support working platforms in the shafts from which the injection grouting operation will take place.