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Cylindrical aquarium housing 1,500 exotic fish bursts in Berlin

theguardian.com

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Re: Cylindrical aquarium housing 1,500 exotic fish bursts in Berlin

#221

Post by jacquesm »

sirsinsalot wrote: post #218
bombcar wrote: post #140

Earlier quoted context omitted.

PSI is a measurement that can be hard to translate between various items like tires and tanks and foundations: https://www.engineeringtoolbox.com/building-foundations-load... Massive tractor tires can be 50+ psi and when they pop it is devastating.

Even my compact saloon cars tires take 45psi

Road bike tires go up to 150 or so... but that doesn't really matter, what matters is that the surface here is massive and you need to withstand all of the force evenly or it will go. Even one crack would do it, it's not going to just seep out water but explode along the fracture, much like a popped balloon isn't going to gracefully deflate.

Re: Cylindrical aquarium housing 1,500 exotic fish bursts in Berlin

#222

Post by KMag »

bombcar wrote: post #140
boppo1 wrote: post #120

Earlier quoted context omitted.

Doesn't seem crazy, my tires hold 38 psi.

PSI is a measurement that can be hard to translate between various items like tires and tanks and foundations: https://www.engineeringtoolbox.com/building-foundations-load... Massive tractor tires can be 50+ psi and when they pop it is devastating.

Side note: tractor tire inner tubes make great trampolines. My aunt and uncle run a small farm (one farm over from the farmhouse where my mom was born) and gave us a tractor tire inner tube when I was young, and we jumped on it enough to require several patches throughout the years.

Re: Cylindrical aquarium housing 1,500 exotic fish bursts in Berlin

#223

Post by sirsinsalot »

jacquesm wrote: post #221
sirsinsalot wrote: post #218

Earlier quoted context omitted.

Even my compact saloon cars tires take 45psi

Road bike tires go up to 150 or so... but that doesn't really matter, what matters is that the surface here is massive and you need to withstand all of the force evenly or it will go. Even one crack would do it, it's not going to just seep out water but explode along the fracture, much like a popped balloon isn't going to gracefully deflate.

Exactly. I shield my anatomy when inflating my tires.

Re: Cylindrical aquarium housing 1,500 exotic fish bursts in Berlin

#224

Post by jacquesm »

abduhl wrote: post #115
lqet wrote: post #108

There are now many reports about material fatigue as the primary cause, but I am not so sure. Another article [0] mentioned that the building is currently analyzed by engineers because the firemen found cracks in floors and walls - they are, however, not sure if these cracks were caused by the water, or if they were already there before . In the latter case, something could be wrong with the building's foundations. I…

Why would you expect the forces acting on the glass to be ill-distributed if the enclosure were tilted slightly? Water pressure acts hydrostatically. The enclosure appears to have a circular cross section. As long as the tilt is not severe there is no reason to believe anything other than tensile hoop stresses due to equal circumferential loading will develop.

That all depends on whether the underlying surface is still perfectly flat around the perimeter. If it is not then you get local stress variations that can lead to catastrophic failure.

The seams between the panels are likely also not designed to be loaded that way.

Just the asymmetrical load on the structure could do the trick at a relatively small angle because it might cause the structure to get compressed against something bordering it. This is not a trivial engineering project.

Re: Cylindrical aquarium housing 1,500 exotic fish bursts in Berlin

#225

Post by jacquesm »

lqet wrote: post #8

Previous thread, with link to article in English: https://news.ycombinator.com/item?id=34012469 Before: https://www.sueddeutsche.de/image/sz.1.5716681/1280x720 After: https://www.sueddeutsche.de/image/sz.1.5716703/860x1290 It seems like the inner glass (for the elevator shaft) is still intact.

What a pity, it looks amazing.

Re: Cylindrical aquarium housing 1,500 exotic fish bursts in Berlin

#226

Post by jacquesm »

pvaldes wrote: post #186
fwungy wrote: post #162

Earlier quoted context omitted.

The hotel was required to reduce its lobby heating due to energy sanctions.

Hum, A graph of the aquarium water temperatures by time would be interesting to examine...

The aquarium was likely very constant (otherwise the fish would die, they tend to be extremely sensitive to variations, especially rate of change), but the surrounding air likely was not.

Re: Cylindrical aquarium housing 1,500 exotic fish bursts in Berlin

#227

Post by jacquesm »

PurpleRamen wrote: post #124
usrusr wrote: post #42

Earlier quoted context omitted.

If it's due to material fatigue it's due to engineering failure. That in turn may or may not be due to the yes-men promotion mechanism.

The tank was around 20 Years old. How is material fatigue an engineering failure at that age?

20 years is a very long time for a structure under such extreme stress. You can bet that this accident will influence all such designs and cause a structural review of every other large tank made of acrylic in the world, as well as various under water tunnels in large aquaria.

Re: Cylindrical aquarium housing 1,500 exotic fish bursts in Berlin

#228

Post by Tossrock »

matheusmoreira wrote: post #154
barbegal wrote: post #117

From an engineering perspective these sorts of acrylic tanks are a nightmare to ensure they are safe. The seams are impossible to inspect rigorously so the only real way of checking that they are safe is to load them with an excess pressure ( https://en.wikipedia.org/wiki/Hydrostatic_test ). This can't be done with a tank of this size so the engineers can only real fall back on giving the tank excessive safety margin…

What's the best material for a tank like this, if not acrylic? Normal glass? Not educated on this subject.

Polycarbonate is stronger and more shatter-resistant (it's used for fighter jet canopies, among other things) but also substantially more expensive.

Re: Cylindrical aquarium housing 1,500 exotic fish bursts in Berlin

#229

Post by marcosdumay »

BatFastard wrote: post #190
matheusmoreira wrote: post #154

Earlier quoted context omitted.

What's the best material for a tank like this, if not acrylic? Normal glass? Not educated on this subject.

Ideally it would be extruded diamond, but that technology will not be available until early in the 26th century. Second would be clear aluminum, but again that will not be available for another 150 years.

The entire problem is that acrylic is not plastic enough, so it fails catastrophically. Well, diamond has all the nice features for structure building, but it's even britter than acrylic. So your sci-fi diamond tank would fail in an even more sensational way.

Re: Cylindrical aquarium housing 1,500 exotic fish bursts in Berlin

#230

Post by jacquesm »

sirsinsalot wrote: post #223
jacquesm wrote: post #221

Earlier quoted context omitted.

Road bike tires go up to 150 or so... but that doesn't really matter, what matters is that the surface here is massive and you need to withstand all of the force evenly or it will go. Even one crack would do it, it's not going to just seep out water but explode along the fracture, much like a popped balloon isn't going to gracefully deflate.

Exactly. I shield my anatomy when inflating my tires.

Watch this guy be very lucky:

https://www.youtube.com/watch?v=B3U3ClFRjrQ

Compared to the side of the truck...

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