Raising more than 800 tonnes of steel hundreds of feet into the air with a margin of error of three millimetres – that was the complex and intricate task to complete the iconic dome structure of Expo 2020’s central Al Wasl Plaza.
The crowning is a key milestone in Expo 2020’s delivery and the result of months of meticulous planning, with the final piece of the 130-metre-wide, 67.5-metre-tall dome positioned with the aid of special lifting equipment. More than 800 engineers and construction experts and technicians worked on the groundbreaking feat, using GPS indicators to ensure perfect alignment.
Comprising 550 tonnes of moulded steel, Al Wasl dome’s crown was precisely positioned using a technique called ‘strand-jacking’: 18 hydraulic jacks, aided by steel lifting ropes connected to 18 freestanding temporary columns, slowly raise the curved steel crown into place. Including the structures and equipment required to lift the dome during this process, the total weight was 830 tonnes.
Al Wasl dome encloses a space of 724,000 cubic metres – the volume of almost 300 Olympic-size swimming pools – and stands taller than the Leaning Tower of Pisa. It uses 13.6 kilometres of steel, the equivalent of the height of 16 Burj Khalifas; weighs 2,544 tonnes, the same as 25 blue whales; and is almost as wide as two Airbus A380 aircraft lined up wing to wing.
The crowning is the culmination of more than 14 months of preparation that began when the final pieces of the dome’s steel trellising left Italy on 26 June 2018. Now positioned, the final piece of Al Wasl dome will be welded to the rest of the trellis, a process that will take 25 days.
Expo 2020’s Official Programme Delivery Management Provider, Jacobs Mace, worked on the overall project management and companies from the United States, Canada, China, France, Japan and Mexico also played key roles in the completion of the dome.
The name Al Wasl means ‘connection’ in Arabic, and Al Wasl Plaza will be the beating heart of the Expo 2020 site, connecting the three Thematic Districts and providing a focal point for visitors throughout the six-month event. Al Wasl Plaza, which includes the dome’s unique structure, was designed by U.S.-based Adrian Smith + Gordon Gill Architecture.
The crowning of Al Wasl dome is the latest milestone in Expo 2020’s fast-developing site, with all permanent Expo-led construction on track to be completed by the end of 2019.