RAISING WEMBLEY’S ARCH
Visible right across London – Wembley’s new 133m high Arch is the most striking feature of the new stadium. A structure of this magnitude means that it needs to be raised incrementally rather than in one continuous lift. The lifting process will include four key stages, altogether lasting between four and six weeks. Even this timescale is dependent on many factors - not least favourable weather conditions.
The Arch will be winched into its vertical position by five sets of strand jacks operating on five gigantic turning struts that are in turn attached by steel (pulling) cables to the Arch.
Once the Arch reaches 65 degrees, the temporary restraining cables on the opposite side to the pulling cables are used to take part of the load and control the position of the Arch as it goes on to move through 90 - 112 degrees. These temporary cables will hold the Arch in position until it is connected to the roof structure.
The whole operation is computer controlled to ensure that the Arch is lifted evenly at all times.
Lifting the Arch is a key phase of the project and over 80 people will be working on the Arch lift that will take place at weekends and at other times when work on the site has ceased and the site cleared.
STAGE 1 – Arch raised to 30°
The Arch is slowly raised to an angle of approximately 30 degrees, with ongoing surveying and checks. During this stage cables for the permanent roof support are attached.
STAGE 2 – Arch raised to 65°
The Arch will then be rotated steadily to 65 degrees, at which point the restraint cables will be engaged.
STAGE 3 – Arch raised to 100°
The distinctive Wembley Arch is slowly rotated through the vertical position to 100
degrees, at which point the three main turning struts are lowered to the ground.
At this time, restraint cables have taken the load and the pulling cables/turning struts are of little use.
STAGE 4 – Arch raised to 112°
Once parked at 112 degrees, and all jacking operations have been completed, the last 2 turning struts are lowered to the ground.
In its final position, the Arch is inclined to the vertical and held in place by 5 restraint cables until the roof perimeter truss is completed and the permanent backstay cables can be connected. The Arch will remain at this position until the roof is erected and connected.
Ultimately, the Arch will support the entire weight of the north roof, 60 percent of the weight of the southern roof and the retractable roof. The unique design of the roof means that there will be no need for columns within the stadium, ensuring that fans will be able to enjoy unobstructed views of the action.