In time for the start of the Olympic Games, London had a new attraction on offer: a walkway over the O2 dome.
The structure with its striking 12 masts located in Greenwich, London, which became famous as the Millennium Dome, now has a 350-metre walkway stretching right over it. By scaling this, daring visitors can reach an observation platform on the very top of the dome. From there you are offered a panoramic view of the Thames and the London skyline.
The 'O2 Roofwalk' posed more than a few challenges for the planners and designers. Unlike the famous 'Sydney Harbour Bridge Climb', the top of the O2 dome cannot be directly walked upon. The only possible solution, therefore, was a separate walkway. It leads visitors on one side of the dome up to the observation platform situated at a height of 60 metres and on the other side back down again. Like the Dome the walkway had to be a tensioned membrane construction that would form a visual and architectural unity with The O2.
The project was designed and calculated by architects Rogers Stirk Harbour + Partners, working with the engineering firm Happold. They then commissioned Base Structures, specialists in tensioned constructions, with implementing the design. One particular challenge for everyone involved was the extremely tight timeframe, as the attraction naturally had to be finished before the start of the Olympic Games.
Mehler Texnologies was contracted to deliver a membrane that can permanently fulfil the extremely high demands made of the walkway's material. The engineers and technicians combined the know-how of the comprehensive product portfolio like architecture or boat materials to one construction project. They developed material prototypes that were tested for all specified material characteristics in a comprehensive series of tests.
The team developed a PVC-coated polyester fabric for architecture application with a base fabric based on a newly developed web technology. Particular attention was paid to the surface embossment, which had to be extremely resistant to sliding and slipping. The embossing had to be pronounced enough for the high surface weight and material thickness as well as for the final coating. This special lacquer defers the abrasion by walk-on in the long term.
The walkway, which has a surface area of 1,175 square metres, was made using this technical textile. In addition to this, there were also the side safety nets tensioned below the walkway. They were made from the newly developed VALMEX® TF 400 mesh fabric. This material possesses an excellent weather resistance and an extremely high load capacity – important properties to engineers and the safety commissioner. In order to ensure that the walkway would be safe to walk along – its steepest gradient is 30 degrees – a full size panel of the walkway was built and volunteer climbers tried out how to walk on it. The 'English weather' in its worst condition was simulated in the tests with rain from garden hoses.
The walkway is made up of 75 sections. These were prefabricated and brought into position using a sledge system specially designed for the task. Using a rope construction, the assembly work was done on a 'freely suspending' basis, as the dome's roof surface cannot take any heavy loads.
On 23rd May 2012, 'Up at The O2' was finished. An adventurous, but safe climbing experience is thus now open to all. Equipped with special 'climbing suits' and climber's belts, which are linked to the platform via a guide cable and the central hand rail, every daring visitor can now get their own personal kick.
