Expo 2020 Dubai lifts final piece of Al Wasl Plaza's dome into place
Hundreds of workers involved in operation that Ahmed Al Khatib calls "the most exhilarating day of my career"
The final piece of Expo 2020 Dubai’s Al Wasl Plaza – designed by US-based architects Adrian Smith + Gordon Gill Architecture – has been lifted into place after “an intricate and complex construction operation” that the team behind the next World Expo has described as a “feat of precision engineering”, with Expo 2020 Dubai’s chief development and delivery officer, Ahmed Al Khatib, calling the operation “the most exhilarating day of my entire career”.
He added: “We had one chance to get this right.”
Enclosing a space of 724,000m3 and standing 67.5m-tall – higher than the Leaning Tower of Pisa – the 130m-wide Al Wasl Dome's steel trellis encircles Al Wasl Plaza, located at the heart of the 4.38km2 Expo 2020 Dubai site.
In a statement, Expo 2020 Dubai said “hundreds” of onsite technicians used special lifting equipment for the operation.
Comprising 550 tonnes (t) of moulded steel, the 22.5m crown of Al Wasl Plaza’s dome had to be precisely positioned on top of the vertical trellis, with a margin of error of 3mm.
Strand-jacking was used for the operation, and including the structures and equipment required to lift the dome during this process, the total weight was 830t – equivalent to 600 saloon cars.
Eighteen hydraulic jacks, aided by steel lifting ropes connected to 18 freestanding temporary columns, were used to slowly raise the curved steel crown. It was positioned directly on top of the trellis already in place 45m above the ground, and attached using 53 temporary connection brackets.
Working through the night, 800 engineers and construction technicians monitored “every millimetre of the process”, using GPS indicators throughout to ensure alignment, Expo 2020 Dubai said.
To retain the geometry of the trellis structure as it was lifted, a series of tension cables was installed, connecting the perimeter of the trellis crown to a central temporary compression ring.
Multiple test lifts were conducted to measure the movement of the structure as it was lifted off the ground, and the tensioned cables were adjusted until the trellis perimeter connection points were in the positions required for the full lift to commence.
Raw steel for the trellis was sourced from the Czech Republic, Hungary, and Poland, and the steel was shaped into its flowing curves by companies in Belgium, Germany, and Spain before being moulded into its intricate latticing in Italy by Cimolai Rimond.
The steel trellis was shipped in batches to Dubai by DP World, Expo 2020’s Premier Global Trade Partner, and Expo 2020’s Official Programme Delivery Management Provider, Jacobs Mace, worked on the overall project management.
Expo 2020 Dubai said companies from the US, Canada, China, France, Japan, and Mexico “also played key roles in the completion of the dome”.
The crowning of Al Wasl Plaza’s dome took 14 months of preparation, starting on 26 June 2018, when the final pieces of the dome’s steel trellising were shipped from Italy. The individual elements reached Dubai in July 2018, and the crown was assembled at ground level before being raised.
The final piece of Al Wasl Plaza’s dome will now be welded to the rest of the trellis through a process expected to take 25 days.
Commenting on the development, HH Sheikh Ahmed Bin Saeed Al Maktoum, Chairman of the Expo Dubai 2020 Higher Committee, President, Dubai Civil Aviation Authority, Chairman, Dubai Airports, Chairman and Chief Executive, Emirates Airline and Group, said: “The crowning of the Al Wasl dome is a significant landmark not just for Expo 2020 Dubai but for the whole of Dubai and the UAE.
“This new architectural marvel joins a long list of inspiring designs that our country has created through collaboration, sheer hard work and the unending, ambitious vision of our leadership and people. It is another example of what the nation can do when it combines all its talents to such formidable purpose.
“Al Wasl dome will take a lasting place at the very summit of our country’s world-renowned architectural achievements. My heartfelt congratulations go to everyone involved in successfully completing this amazing engineering feat.”
During Expo 2020 Dubai, Al Wasl Plaza’s dome will be the largest 360° projection surface in the world, and its crowning is an important milestone in Expo 2020 Dubai’s construction programme, as part of which all permanent, expo-led works are planned to complete by end-2019.
Remarking on the crowning, Al Khatib added: “Crowning Al Wasl Plaza’s dome was both incredibly exciting and one of the most challenging engineering operations in the world.
“Lifting such a large and heavy structure involved a huge number of variables. Something as simple as a shift in direction of the wind or change in air temperature could have had a big impact on our calculations, so constant monitoring and reassessment was essential throughout the process.”