The size is almost unlimited even with current technology.
I’ll give you three large if not the largest covered structures.
New Century Global Center (NCGC) in Chengdu, China, is the largest unsupported roof structure in the world with a steel-glass barrel-vaulted roof that spans 450 m x 200 m.
Total unsupported-by-columns roof area is 90.000 m2.
Total footprint of the building is 200.000 m2, reaching 100 m height and with a total usable space in several levels of 1.700.000 m2, or 1.7 square kilometers
Inside the barrel vault roof there are:
- the Paradise Island Water Park complete with an artificial beach and LED lights that simulate sunny season even in winter
- Olympic size skate ring
- Pirate Ship attraction
- Mediterranean style village
Inside of the barrel vault
Exterior of the barrel vault, those lateral concrete blocks are entire 12 stories buildings
This thing reminds me the Arcologies of Sim City, it is like an entire city inside the city of Chengdu
The center has a 1000 room Intercontinental Hotel, one University, two separated commercial centers, and an IMAX cine.
Thanks to William Adams for the correction, I had just mentioned AT&T Stadium only.
Until NCGC was built, the AT&T Stadium at Arlington, Texas, had the largest unsupported-span roof structure in the world.
The longitudinal span is 373 m.
Transversal span must be around 180 meters, it has a 78 metres wide retractable roof over the football field.
Total area is 61,400 m2.
Interior view of AT&T stadium showing the astounding longitudinal beams without intermediate columns at all, only columns are at the outer walls (periphery)
AT&T Stadium with roof closed
For comparison, Bird’s Nest in Beijing has dimensions of 332 x 220 meters, which are relatively close to AT&T but almost 20% smaller.
However, it has an inner opening with dimensions of 190 x 125 meters, give or take.
Thus, the area covered by the outer elliptical sector is:
A=π×(3302×2202−1902×1252)≈38,000 m²≈410,000 ft²A=π×(3302×2202−1902×1252)≈38,000 m²≈410,000 ft²
Bird Nest has no retractable roof as AT&T Stadium, which is a monster of a roof.
