Circular Rotating Pedestrian Bridge is a pedestrian bridge that takes the form of the perimeter of a large disk, but without any spokes or central connecting material. Imagine a flattened bicycle wheel with no spokes or hub turning on a horizontal plane.
Circular Rotating Pedestrian Bridge is supported at either end by a set of motorised rollers that also cause the entire disc to rotate at walking speed in either a clockwise or anti-clockwise direction.
Pedestrians, cyclists etc simply step onto the structure at either side (of a river for example) and are carried in a semi-circle to the opposite point where they step off again. Runners can exercise by travelling counter to the rotation, and divided lanes provide for this feature.
You can walk, run, cycle or just stand still and admire the view as you are transported sedately on your way.-- xenzag, Dec 27 2017 Nice. [+]
Make it wide enough to put chairs and tables on it. Put a café on each bank. Watch the world go by.-- 8th of 7, Dec 27 2017 The rim of such a bridge will be the fastest-moving part. Normal adult walking speed is about 3 miles per hour (a bit less than 5 kph), so if you want folks to leisurely step onto or off of the bridge, the rim should not be moving faster than that.-- Vernon, Dec 27 2017 A continuously arising and retracting perimeter barrier prevents anyone from taking a dive..... piffling details.-- xenzag, Dec 27 2017 Yes, that's one way of doing it. A barrier that is cammed down and up again at the access points would do.
However ...
On further consideration, and much to our astonishment, it looks like you might have hit on something really clever and innovative.
It is genuinely painful to admit that, but the truth must be told.
This can be built as a lift bridge.
The development became obvious when considering the problem of a personnel barrier at the edges of the ring.
Without such a barrier, users might fall off into the water. This is not a problem per se, indeed it would be a welcome source of free entertainment, but some might be café customers who haven't paid their bill yet. Such financial risk is unacceptable.
A barrier that rotates with the bridge, dropping down and rising again at each side, is mechanically complex and possibly a trap hazard. Some idiot might damage themselves, resulting in bad publicity.
So:
The bridge is built as two "C" sections, one on each bank. When lowered (a bascule mechanism is envisaged) the open ends of the Cs are in contact, and lock together - probably by hydraulics.
Around the inner and outer perimiters of the ring thus formed is a simple fixed safety barrier.
Within the C-sections are rails, on which two smaller C-shaped running decks rest. These too lock together when the brige is down. These are the parts that actually rotate. Before the bridge is opened, the breaks in the deck ring are aligned with the breaks in the suport ring, and the two locked in position.
At each end of the bridge is a travellator, tangential to the bridge ring, and moving at 3 kph. The circumferential translational velocity of the bridge is 6 kph. This allows efficient speed matching.
A user steps onto the travellator and accelerates to 3 kph, then to 6 when they step onto the bridge. At the exit, the process reverses.
Pedestrians would move along the outer circumference; the chairs and tables - fixed in slots in the deck, to stop them falling off when the bridge opens - would be along the inside of the annulus.
This also offers the intriguing possibility of employing the centre as a performance space, in which violent and pointlessly cruel spectacles - typically involving desperate, impoverished foreigners specially imported for the purpose - could be staged.
Of course, non-violent sporting, dramatic and cultural events would also be possible, but why this would be done remains unclear.-- 8th of 7, Dec 27 2017 Once a year it could be switched to "centrifuge, wall of doom mode", with the perimeter barrier slowing retracting as the speed increased....-- xenzag, Dec 28 2017 Oh, yes, please ... <snigger>-- 8th of 7, Dec 28 2017 [+] This could be made seethrough and be an observation disc over a waterfall or cliff panorama.-- wjt, Dec 29 2017 // have you performed any recently, //
Yes.
// and what was the outcome? //
Ant and Dec. The paperwork was a mess, we misread "Termination " as "C-section.
We're really sorry.-- 8th of 7, Dec 29 2017 random, halfbakery