The installation of the pre-fabricated lift shaft at Southfields Underground Station was successfully completed as planned on the night of the 3rd February 2010.  The installation of the shaft represents the completion of the first in a series of key milestones for the project enabling step free access from street level to platform level, in time for the Wimbledon tennis tournament on the 21st June 2010.

 

The prefabrication and craning into position of the lift shaft was devised by the project team as a programme mitigation measure to reduce the amount of onsite construction works required. 

 

Measuring 3.5m x 3.5m x 11m high and weighing in at 7˝ tonnes, the lift shaft is situated on the existing platform only inches from the kinematic envelope of the trains.  Because of this, much of the work on site can only be undertaken during Network Rail Engineering Hours, resulting in extended programme durations for many site activities.

 

The structural steel shaft was constructed in Belfast in the yard of the specialist subcontractor McGrath Engineering, and inspected and checked by the site team who enlisted Sandberg to assist in the inspections of the welds, member sizes and accuracy of the assembly.  From there it was transported to the cladding contractor’s yard in Cambridgeshire, where galvanised liner sheet, insulation and Corium under cladding were added.  Again inspections were undertaken offsite prior to the delivery to site on the night of the 3rd February 2010.

 

To enable the installation on the night, two cranes were required to ‘top and tail’ the lift shaft from the back of the delivery wagon.  Subsequently the larger of the two cranes (150T) lifted the lift shaft up and over the top of the station, and into position over the holding down bolts cast into the reinforced concrete lift pit constructed some 10 days earlier.  Despite the short window of opportunity this was successfully completed with 20 minutes to spare.

 

The prefabrication of the shaft and partial cladding of the structure secured a saving of some two weeks on a very challenging contract programme for the cladding works, enabling Otis to begin on site some six weeks earlier than otherwise possible.