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covered wooden bridges? colossus have to look like arch
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This list contains the largest ceiling spans in the world, that at least have the strength to support some persons. It is decided that roofs made of canvas etc do not have that strenght. There must be no supporting pillars in that part of the ceiling constituting the span.
The span of a square room is equal to the length of a side of the room. The span of a rectangular room is equal to the shortest side of the room. The free span of any room is calculated like this: Place the largest possible imaginary horisontal circular disk inside the room, barely touching any load-bearing pillars or walls, or parts used to stabilize the roof. The disk must also not encircle any objects of this kind. The disk have to be completely covered, that is rain-sheltered, by the building. The span of the room is equal to diameter of the disk.
Example: The O2 (former Millennium Dome) has an overall diameter of 365 m. But it has a jagged edge so an imaginary disk of this diameter would not be rain-sheltered. When the disk is shrunk to O2's internal diameter 320 m it become rain-sheltered by the structure, but this is still not the free ceiling span because the disk is encircling the twelve load-bearing pillars located under the roof. When the disk is further shrunk to 206 m it is only slightly touching the innermost side of the pillars, so this is finally the clear ceiling span of O2. Note that since the pillars are lending outwards, the largest span is not found at the floor level, but some metres up the pillars until were a wire is connected that stabilizes the roof. A disk of this size is encircling a lot of non-load-bearing walls of O2, for example the walls of the O2 Arena which has it's own roof. Since the O2 Arena structure is not supporting the O2 structure, that doesn't matter.
- Note: Click on each bridge's rank to go to the bridge's official web-site. Ranks with a red asterisk (*) do not have official web-sites, or do not have English language versions and are linked instead to a reference entry.
- The indoor photo shows the room and the ceiling "prooving" there are no supporting pillars.
||Ceiling span in metres (feet)||Year opened||Note|
|Linked photo||Ōita Stadium||Ōita, Ōita||245 (803 ft)||2001|
|Nantong Sports Centre||Nantong||240 (787)||2006|
|Reliant Stadium||Houston||224 (734 ft)||2002|
|Seibu Dome||Saitama||220 (721)||1999|
|Sapporo Dome||Sapporo||218 (715)||2001|
|Sapporo Dome||Sapporo||2,180 2,180 m (7,152 ft)||2001|
|Sapporo Dome||Sapporo||21 21 m (69 ft)||2001|
|Linked photo||||The_O2||London||206 (675)||2000|