The world's largest wooden structure has been completed. Aptly named the Grand Ring, it takes the form of a massive circular loop with a walkway on top and has a circumference of approximately 2 km (1.2 miles).
The Grand Ring has been created for the Osaka 2025 Expo event that's currently underway in Japan, and was designed by Sou Fujimoto Architects.
It was constructed using both modern techniques and Nuki joints, which is a traditional Japanese method that's used to connect wood without using nails or screws. Most of the wood used is local cypress and cedar, but some is Scots pine.
It has been officially certified as the world's largest wooden structure by the Guinness World Records and has a width of 30 m (98 ft), plus an outer edge diameter of roughly 675 m (2,214 ft). It encircles the Expo site and is topped by a walkway called the Sky Walk at a height of 12 m (40 ft). This is lined with a large amount of flowers and allows people to stroll on top and take in views of the many pavilions and of the surrounding area.
"The Grand Ring is the symbol of Expo 2025 Osaka, Kansai, Japan and expresses the concept of Unity in Diversity," says the Expo's press release. "It is constructed using a fusion of modern construction methods and traditional Nuki joints, such as those used in the construction of Japanese shrines and temples. It will serve as the main route of visitor traffic around the Expo site, enabling smooth movement around the site and offering visitors a comfortable space sheltered from the wind, rain, and sunlight."
The Grand Ring was originally designed for easy dismantling once the event comes to an end on October 13, however Japanese authorities are considering keeping it in place and, to this end, are soliciting ideas from locals on what it could be used for going forward – Paris' iconic Eiffel Tower was originally intended as a temporary structure made for an expo, after all.
Large-scale timber construction is really gaining pace in recent years and other notable examples include an airport in Portland that has a 9-acre (3.6-hectare) roof and the world's tallest wooden skyscraper in Milwaukee.
Sources: Expo 2025, Sou Fujimoto Architects