WEMBLEY STADIUM'S signature roof arch is being primed for a dramatic lifting sequence next month.
Delivery of the final piece of the arch was due earlier this week. It is being assembled in a horizontal position ahead of the four to six week lift.
Steelwork subcontractor, Cleveland Bridge is responsible for the arch raising operation.
The pencil-ended bases of the 315m span, 7m internal diameter lattice arch have already been connected to a pin joint which will allow the arch to rotate as it is raised.
The bulk of the lift is expected to take place in February and March depending on the weather.
Raising the 315m long structure will follow a similar procedure to that used on the London Eye in September 1999 (NCE 16 September 1999).
'Cables will pull the arch up from the ground. To do this, they will run over temporary towers that will provide an angle to generate the initial upward force, ' said principal contractor, Multiplex project director Ashley Muldoon 'For the London Eye, one central support tower was built.
This remained stationary during the lifting process. But at Wembley, five such towers will be used - and this time they will be moving, ' said Muldoon.
The temporary towers are designed as turning struts and have been built between the arch and the jacking points. Two of them are 46m tall, two are 82m and the centre support is 102m.
These will rotate on their bases in the direction of the arch's movement, helping to maximise the performance of the jacks and reduce the compression forces.
Engineers have studied problems encountered with the London Eye lift to ensure the Wembley arch operation runs smoothly.