Art&Engingeering - The Rolling Square Bridge 5

[human909]

I thought I'd share this. It is neither a question nor so I present particularly insightful commentary on it. I just though that it was a beautiful combination of art and mathematics into one of structural engineering's oldest challenges, bridge design. To whet your appetite. The openable bridge is hand operated!

A great overview of what is going on is here:

https://www.youtube.com/watch?v=SsGEcLwjgEg

It focusses more on the mathematics than on the structure which probably isn't particularly novel once all the other stuff is sorted.

Enjoy

 

[ALK2415]

My point !
the rolling of large weights is entirely based on bottom "gearing racks", that attached to the sides of concrete walls of channel, facilitate the linear (lateral) movement

 

[IRstuff]

The gearing rack is actually cooler than that, since the objective is to roll a non-circular shape. The physical movement uses a looped cable

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert!

https://www.youtube.com/watch?v=BKorP55Aqvg

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[GregLocock]

I wish they'd driven it with a giant hamster wheel, but I suppose it is hard to get giant hamsters these days. If the cg is at the same height throughout then it is neutrally stable in all orientations, they could have altered the path so its only stable configs were in the initial and final position, but then the winching efforts would be higher.

Cheers

Greg Locock


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[JLNJ]

Fascinating, but it looks like a good place to lose an arm!

 

[BridgeSmith]

Fascinating, but it looks like a good place to lose an arm!

Only if your reactions are very slow, or you're trying to get it amputated. As was previously noted, it's a time-lapse GIF. It supposedly takes it about 20 minutes to turn over.

 

[human909]

It continues to amaze me that one of the most frequent comments has been about safety of the bridge. I don't see a big difference in safety to the many thousands of other types of openable bridges in the world today.

What I personally found most interesting was the simplicity of it in appearance combined with the complexity of a rolling square with a neutral centre of gravity.

IMO it is a beauty of engineering. I'd place other structures like the one picture below in the same category, combining form, function and simplicity but underneath that simplicity the mathematics/engineering to get it right is complex.

EDIT: I just realised that both structures are heavily dependent on the catenary curves.

 

[phamENG]

I don't know...the back of the roof is awfully close to the ground...kids might run up it and try to somersault off the high edge...

 

[IRstuff]

It supposedly takes it about 20 minutes to turn over.

Matt Parker's video shows him cranking on the handle driving the cable takeup, and it didn't look particularly easy, so it's likely nearly impossible to get body parts damaged, since the operator has a clear view of both sides of the channel and there are barriers put up prior to translating the bridge.

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert!

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[Brian Malone]

Very cool bridge and engineering.

Hand cranking adds to the beauty and simplicity of human and machine.

For me, the weathering steel detracts from the aesthetic presentation of the form but it works for cost/budget constraints and those liking a gritty industrial look . . .

https://community.wolfram.com/groups/-/m/t/2917199