[lqet]

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 am no expert, but if such a massive aquarium is only slightly tilted to one side, I would expect the forces acting on the glass to be ill-distributed. Material fatigue would then only be a secondary cause.

[0] https://www.faz.net/aktuell/gesellschaft/ungluecke/aquarium-...

[swader999]

The hotel was told to lower their temperatures. With cold weather outside the differential between the tank and the lobby is the most likely cause.

[jacquesm]

That's a good guess, but I'd still like to see the final report if and when it is published and whether or not they manage to find the root cause. Likely the differential made the problem worse to the point that something gave but I suspect that there is a deeper underlying cause that made it sensitive to that difference in temperature to begin with. Either a material flaw, an assembly issue or something else.

[fuzzfactor]

Seems to me it must have been a salt water tank if it had clownfish, and they are tropical so it's not just exposing the acrylic to constant warm water, but a more realistic marine environment.

In the lab I've chemically tested acrylics that were bullet-resistant at low-cm window thickness. No bullets were used in my phase of the operation, but I was clipping off chips from the exact coupons which had been physically measured beyond the fracture point.

You can tell there's a difference in ductility and brittleness with temperature. Pretty tough stuff regardless.

In the aquarium these are supposed to be very thick-walled acrylic curved panels bonded together.

If the water was maintained warm enough for the reef fish while the ambient air dropped below freezing I don't like that idea. The entire temperature differential being borne by the thickness of the acrylic could mean there are different plastic properties diverging among the inner and outer surfaces of the "glass" panel. This could give rise to stress being concentrated deep within the panel if the transition is not too smooth.

Conditions like this could be recreated if so.

Might have been OK if they had penguins and cold-water fish this time of year.

[swader999]

I'm basing it off of what this guy is reporting. He seems to have an inside legit view. https://www.zerohedge.com/user/105370

[jacquesm]

There are some eye witness accounts about corrosion around the base of the tank. One way in which that could have caused this is because corroded metal takes up more space than the original and this could put point stresses on the acrylic. I haven't seen any engineering drawings (I did try to find some but there are only pretty pictures) so I'm not sure how much effect that would have but keeping the base corrosion free would seem to be an absolute requirement regardless of whether or not it would have a disastrous effect like this. So I will have to wait until the investigators have gone all over this, given the amount of money involved there is bound to be a very thorough investigation and after having seen a couple of aircraft accident investigations conclude with entirely different findings than the first 24 hours of speculation I've learned that to be patient usually pays off.

[swader999]

That is fair. Security tapes might tell a lot as well.

[jacquesm]

Those will definitely be interesting, if they are leaked. Let's hope the cameras have a high frame rate because the first couple of frames will be the most interesting with respect to where the failure started and how it propagated.

In the Panama City there is an overhead swimming pool many meters above the restaurant floor. I've dined there a couple of times and never feel quite comfortable with that much water hanging over me supported by a sheet of acrylic.

After this that feeling is likely not going to be any less :)

[elliekelly]

Zero Hedge is not a reliable source of information. They also tend to push a lot of Russian fake news/propaganda. And of course Putin would love to have a major news item showing how the West’s gas sanctions have harmed the West.

[swader999]

Yeah, it's a nice balance to the murican propaganda.

[UnquietTinkerer]

Wow, that guy is ... extreme. I'm glad you posted the link, but I'd personally take any conclusions he draws with a grain of salt.

[abduhl]

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.

[a4a4a4a4]

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.

[abduhl]

If the tank burst due to it shearing off of its base then it is not the glass that has the problem; it’s the connection to the base. This might sound pedantic but the OP said the forces on the GLASS were ill-distributed. The most important part of after the fact disaster analysis from an engineering context is being excruciatingly specific about the performance of structural elements.

[upsidesinclude]

If you wanted to be pedantic you would correct the statement because there is no glass.

To be excruciatingly specific.

[abduhl]

The article refers to the aquarium as glass throughout it.

[kayodelycaon]

The material used is plexiglass, aka acrylic, a type of clear plastic. Actual glass is probably too brittle or expensive.

People use "glass" to mean the clear part of a window, not the actual material, in this context.

[lqet]

But isn't the overwhelming majority of the glass material connected to the base by the glass itself (namely the glass below it)?

[jacquesm]

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.

[bombcar]

I would expect it's not the tilted slightly that would matter but simply settling after installation - a settling foundation can crack concrete and glass so stresses could change if the foundation of the tank was moving.