Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Cylindrical aquarium housing 1,500 exotic fish bursts in Berlin

theguardian.com

Post reply on HN
Print view View original

111–120 of 265 posts

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

#111

Post by lsaferite »

jacquesm wrote: post #76
yreg wrote: post #45

Earlier quoted context omitted.

For how much longer than his UPS could provide it?

A couple of hours only.

I'm sorry for your friend's loss and for the lost livestock, but it seem like it was simply a ticking time-bomb.

If your friend had 30 tanks and thousands of fish, they should have had a more involved backup plan that involved a dedicated generator in addition to a UPS. A small generator would have been a tiny fraction of the materials and livestock costs of running a setup like that.

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

#112

Post by pixl97 »

rzzzt wrote: post #79
ChuckNorris89 wrote: post #46

Earlier quoted context omitted.

Fatigue from what? It's a stationary object housed indoors, not a car or plane that goes through several climatical, temperature and environmental changes to cause fatigue. Unless they were subjecting the tank to draining and filling cycles often, it seems more like a design/build fault that was a ticking time bomb from the start.

Buildings move.

This here.

The earth you live on is not solid, more like a squishy orange. When you build a heavy building on it, the building can sink further.

Buildings themselves are subject to the dynamic loads of temperature, wind, their occupants square dancing, and more.

Sometimes unexpected loads are added. A new highway or building built into a rock layer near it can subject the previous building to vibration and other forces and cause damages.

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

#113

Post by koonsolo »

zython wrote: post #21
Fricken wrote: post #2

Weird. Earlier today I awoke from a nap after strange dreams and attempted to produce images in midjourney of a giant aquarium breaking. I must psychic or something.

Please dream of me winning the lottery and or becoming 10x dev.

You do realise that becoming a 10x dev will mean you're getting underpaid? It's better to become a 0.1x developer so you're sure you're getting the better end of the deal ;).

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

#115

Post by abduhl »

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.

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

#116

Post by sidlls »

ChuckNorris89 wrote: post #46
feb wrote: post #33

According to a german news report [1], it could be due to material fatigue. [1] https://www.rbb24.de/panorama/beitrag/2022/12/berlin-karl-li...

Fatigue from what? It's a stationary object housed indoors, not a car or plane that goes through several climatical, temperature and environmental changes to cause fatigue. Unless they were subjecting the tank to draining and filling cycles often, it seems more like a design/build fault that was a ticking time bomb from the start.

Settlement of the building it's housed in, temperature variations (things contract and expand as temperature changes), random impacts and vibrations (e.g., road traffic, heavy construction nearby), and so on. All of these contribute to fatigue.

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

#117

Post by barbegal »

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 margins. But those safety margins cost hundreds of thousands of dollars for a tank this big so maybe they were reduced.

All it takes is one incorrect application of a seam bond and a small crack will form. The crack may take decades to propagate with no way of detecting it. When the seam opens up a bit the crack will then propagate the entire length of the seam extremely rapidly and the whole tank will fail. Ideally failures would be slow and predictable but this is impossible with acrylic.

These sorts of failures have occurred before https://www.plasticstoday.com/materials/when-acrylic-aquariu... and will keep occurring as long as this type of construction is used.

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

#118

Post by a4a4a4a4 »

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.

The normal force of the tank wall to the floor will shear across the acrylic if it's not perfectly flat. Pressure outwards is normal to the tank wall relative to the water, but if this force goes diagonally through the floor, that's bad.

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

#120

Post by boppo1 »

MengerSponge wrote: post #104
jacquesm wrote: post #69

Earlier quoted context omitted.

A column of water that tall is nothing to mess around with. Even the smallest imperfection in the base materials can become a problem.

170.65 kPa, or 24.75 psi. I imagine even Flex Tape can't hold that!

Doesn't seem crazy, my tires hold 38 psi.
Post reply on HN