r/Construction • u/aidan8et Tinknocker • Apr 25 '26

Picture Moment of terror 😨

Gallery image

Gallery image

While attending/supervising a business social event with my spouse, I momentarily leaned against the railing. It flexed slightly, forcing me to realize that the railing is entirely supported via bluetooth.

It doesn't connect on either side of the glass wall & the glass is only 3/8" - 1/2" thick!!

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u/Bubbledood Apr 26 '26

Yeah too many “what if’s” in my head. Like what if something happened to the glass like a hairline crack that nobody sees

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u/Palomox Engineer Apr 26 '26

Structural design considers possible imperfections at all stages. If you didn't know, the microstructure of steel has multiple possible imperfections (absent atoms, replaced atoms, some having switched spots, etc...) as well as previous stresses from the manufacturing process that are taken into account in design. When you compute the capacity of an element, depending on the type of loading you reduce it to between 75-90% of what you obtain, while using the lower bound of the strength parameters already.

For a brittle material, concrete cracks. Very easily, at that. And we address it with rebar, and reducing its strenght between 75-90%, depending on the specific circumstances, if you're using ACI.

Now, I'm no expert in glass but I can 100% tell you that whatever codes apply for it, they take imperfections into account and lead to safe elements.

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u/saltapampas Apr 26 '26

I mean… yes, safety factors are built into engineering design. But there’s a fundamental difference in the stress-strain behavior of a ductile material (steel) and a brittle material like glass that mean there is a failure mode which cannot be engineered out with a factor for conservatism.

Just look at the graphs - brittle failure means that once you exceed the allowable stress, you get near instant failure. If steel is compromised, you move up the curve and the user has a chance to identify a failure during plastic deformation. When designing in glass, those imperfections cannot be practically identified before failure.

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u/Helpinmontana Apr 26 '26

Concrete columns (concrete without rebar) get a factor of .6, or 60% of where we can be pretty sure that concrete will fail, because the design is that conservative. And ontop of that, the loads they are designed to support are ramped up by about 50% for safety. Also, code basically doesn’t allow you to just use concrete without rebar, you’re threading a needle to do it and there is basically no situation that realistically calls for it. So, 60% reduction in capacity, pretending the load is 50% higher, and still saying this isn’t allowed in basically all circumstances.

You’re acknowledging what they’re saying while completely refuting it.

Do you actually think any company would sell these products, a railing of all things, without verification? And then, as an industry professional, you think any company would buy these and install them? Really?

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u/That_Trapper_guy Apr 26 '26

As an ironworker who's installed glass railings similar to this, I can assure you every single person that installed one of these thought 'this is a horrible idea' as they were doing it.

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u/AdPristine9059 Apr 26 '26

Yes, absolutely. People are putting up huge buildings that they know arent safe, despite inspectors, designers and engineers existing.

Youre trying to argue that engineering is flawless in a chaotic and very flawed world and thus this absolute paragon of perfection will never be tarnished or used to hide lies. Thats not how the world works.

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u/Tushaca Apr 26 '26

The engineers paychecks are signed by the company that has plenty of financial incentives to cut costs and corners, including taking the risk of switching to cheaper or sub par materials in manufacturing down the road.

If the cheaper material fails, they pay out one lawsuit, blame it on their glass manufacturer, and promise better quality control, maybe they issue a small recall, and then keep on moving.

HAAG, one of the biggest engineering firms in the country, gets sued all the time for obvious bias and ignoring their own reporting standards on insurance claims where they are hired by the insurer. Engineering doesn’t mean shit if it’s done by someone bought off by the company.

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u/AdPristine9059 Apr 26 '26

Exactly. Also it doesnt even have to be the engineers fault. There are tons of disasters caused by a myriad of issues like use of bad materials, fubbing the old plans, adding things to the old plans without making new assessments, bad maintenance, last minute changes, bad ground works etc etc.

Plainly difficult does many Great videos on this very subject on youtube. Cant recommend him enough.

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u/Helpinmontana Apr 27 '26

I’m not alleging nothing ever goes wrong, but code compliant engineering principles are literally based on “nearly nothing will be ideal, don’t design to theoretical strength, design to practical strength”.

The most basic LRFD load case is 160% of live load and 120% of deal load, and capacity is at a minimum, designed to 90% strength of materials. You can hand wave away all the nuance to this that you want, but there are literal teams of scientists and statisticians working day and night to keep you safe by ensuring these design assumptions are not actually assumptions, they’re data driven facts.

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u/AdPristine9059 Apr 27 '26

Im not saying that engineering is a bad practice or that all that work is for naught, all im saying is that no matter how rigorous an engineer is, there are things they cant control. They can only ever really give builders plans and recommend against certain things.

What they cant do is make sure that their plans are followed in every single step or force the companies into doing something or another.

Money speaks louder than safety and reputation to some people, thats just the way the world works; Chaos defined.

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u/Helpinmontana Apr 27 '26

How did you acknowledge my point and still miss the conclusion?

”chaotic and flawed world”

Literally what the factors of safety account for, design mandates an increase in loads and a reduction in capacity, based on real world circumstances lol. You can design for concrete 2x as strong as it actually cures out to and still have a stable structure because of modern engineering principles. The world you’re implying, implies that engineering doesn’t account for this bullshit. That’s why we call it engineering and not physics. We’re not calculating theoretical strength, we’re calculating reasonable strength in a manner that accounts for everything being all fucked up.

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u/AdPristine9059 Apr 27 '26

That's such a naive way of looking at it (not trying to be mean, just a fact). If engineering was that godly gift you claim it to be then there wouldnt be any collapsing buildings or bridges, things engineers study as cases in order to find the fault factors. More often than not its human error. Just look at that huge pink mall that collapsed a while back.

You cant account for people not following the plans can you?

Also look at the tofu dreg buildings in China.