In Xi’an, the national capital of ancient China for more than 1,000 years and once the eastern terminus of the Silk Road, stretches a vast low-lying modern aluminium clad building along the banks of the Xi River.
In a nod to the city’s ancient name of Chang’an, the landmark building is called Chang’an Cloud. Designed by China Northwest Architectural Design and Research Institute and commissioned by China Construction Shenzhen Decoration Co.,Ltd and China Construction Third Engineering Bureau Group Co.,Ltd, its form was inspired by cloud formations.
Chang’an Cloud is composed of two main parts. The front section is approximately 180m long, with 110,000sq m of the building above ground and 70,000sq m underground. This part contains the sky restaurant, exhibition centre and offices while the rear section is about 250m long and is composed of two ‘flowing clouds’, or buildings that contain the Xi’an science and technology exhibition centre and planning exhibition centre.
Race against time: aluminium architecture
For Almeco, this project was a race against time as the aluminium cladding had to be finished for China’s 14th National Games, the largest premier multi-sport competition in the country. Almeco began producing the anodised aluminium in April 2021 and the Games officially kicked off on 15th September 2021, so it was a challenging project.
To meet this tight deadline, thanks to the lightweight of the aluminum, over 95% of the anodised coils were sent to China by air rather than being shipped by sea.
Once the coils arrived in metalwork factory in regular deliveries, the 1mm thick anodised aluminium was cut to size. A honeycomb core of aluminum was sandwiched between it and aluminum alloy bottom layer.
The coupling of the two layers creating a total thickness of 20mm, helped to make the panels stronger and flatter while the honeycomb pattern reduced the overall weight of the material.
The panel widths varied from 1,250mm to 1,500mm and the lengths ranged in size and were cut to fit depending on the part of the building the panel was being fixed to.
Aerial view of Chang’an Cloud
Bespoke aluminium aesthetic: Almeco and the Shenzhen Rehongda Building Technology Company
Almeco’s Partner, Shenzhen Rehongda Building Technology Company, specified anodised aluminium to clad the building not just for its well-known characteristics – which include its recyclability, strength, lightness, and fire-resistance – but also for its amazing aesthetic advantages.
For Chang’an Cloud, the client wanted Almeco to reduce the visual impact of anodised aluminium’s natural shininess by creating an enhanced matt aesthetic. This bespoke finish required samples being made in Almeco’s laboratory.
“We didn’t have time to make trail coils given the tight deadline, so the R&D team made some lab samples which were flown over to China and checked by the client,” says Luca Accastelli, International Key Account Manager.
“To achieve the new ‘silky-metallic’ look, a special alloy was developed and used in a dedicated etching + anodising process”, explains Matteo Amadini, Production Leader at Almeco Group. “The collaboration and the coordination between the R&D and production teams showed great capability and exceptional flexibility in achieving this goal within such a challenging deadline. Actually, the customer was very satisfied with the final result”.
Aluminium architecture: Chang’an Cloud
Near where the completed Chang’an Cloud is situated, a lot of the land is currently being developed. With this area changing fast, people won’t just be visiting the world-renowned Terracotta Army, which Xi’an the capital of Shaanxi Province is famous for. They will also be drawn to this newly developed part of the city with the eye-catching anodised aluminium skin of Chang’an Cloud being a star attraction.