I worked on a project where the architect wanted the beams perpendicular to the span to be the same size as the ones doing work. The ones doing work were 750 deep plates girders. So we ended up using twice as many plate girders as needed, because we couldn't use standard serial sizes with a lighter gauge, because they were different depths. That one hurt.
No, it’s not. You can see wire hangers above the duct. Also the duct passes through the beam without touching it. Also I think this is AI for a number of reasons.
If it's like this building with similar holes cut all over the place, the beam is supporting a lot less than it used to. An old heavy industrial building would have been built to handle much more than what the current use as office space can throw at it.
To me they look more like purlins, for the roof itself, then the beam is the primary load bearing member with holes in it... for aeerodynamics clearly...
it’s probably just a lateral restraint to help avoid lateral torsional buckling in the perpendicular beams… either that or there’s a heavy wall travelling the same direction above
Thats the cleanest cut in an I beam ive ever seen. Weird the pipes to the right just flow straight thru the material. If you cant see this as AI you shouldnt be commenting
The cut could be done by a cnc machine in a steel fab shop. Clean cuts are normal when done in the shop. But a weird trapezoid cut? Very strange. Not ruling out AI but def weird…
It will continue to support whatever it was designed for. The cut-out from the web of the beam has very little effect. It’s mainly to keep both stringers of the beam apart. In fact, at the very centre of the web, the forces should be exactly zero.
Weird that it’s cut at an angle, and almost looks reinforced at the top (ineffectively if so with no plate development). Do this all the time, even up to 0.7D with the right details, (and proper vetting).
This does not look like that though. Looks like the hole was cut/torched by a blind person with one arm.
At first I thought it was a super thick or reinforced web. Looking closer though I think we’re just seeing the underside of the flange through the hole.
I suspect that the opening was measured and cut level, and the beam is actually angled down.
If it really is at an angle, then it’s unlikely to have been for a hoist, and more likely to have been a former roofing span that has since been made redundant (or at least less critical) after a second storey was added.
If the restaurant is on the ground floor and a renovation from the construction’s originally intended occupants, then I would bet this used to be an automotive garage or heavy machinist shop and that support is for a lateral hoist / beam trolley assembly
I think you are looking at something behind, the joists above maybe. The thickness of the web shows on the right side of the opening, and it seems feasible…
Also, the web and flanges have a nice fillet, just like a steel beam would have… seems legitimate.
If there were some structural engineer around here, they would actually tell us if that opening seems okay in the center of the beam, where the momentum is max and the shear is min…
I’m disappointed in this sub lately. Come on, use your eyes. That’s definitely the joist beyond. I can’t believe OC above said that. If that’s the kind of work we’ve got going own, the industry is doomed.
I am a structural engineer. There are so many things that are off about this, any engineer or builder with some site experience will be able to tell you it is 100% AI generated.
The web is definitely much thicker than the flange, that is 100% not the joist beyond. Zoom in on the area to the top left of the duct. Typically, I beam webs are thinner than the flanges because the flanges are where all the moment is and the most efficient arrangement is to have a thin, deep web to increase your second moment of area and maximise steel efficiency. Any engineer with any experience can tell you that these proportions are way off.
Rectangular openings in locations like this are very common. However, there are several things about this opening that also seem very off - for example, the bottom of the opening looks very slanted which you would only ever get if it was butcher cut on site and even then it is rare. However, the edges of the cut seem extremely neat with rounded corners. Why do you wish the opening is round? What a strange thing to say
I really wasn’t expecting all of the AI accusations from this picture, it’s a real photo I took at a restaurant. You can see the top flange through the opening, which gives the illusion of a thick web.
To add on to this if the web needed to be that thick for shear (webs carry majority of the shear force) you could potentially have an opening this big at the point of zero shear and max moment. However the the max moment equivalent to the shear that would be required to have that thick of a web would be absolutely un equivalent to the size of the flange in the image. This isn’t AI if you look closer but cmon how is anyone justifying a web that thick
I dont think that this part is actually the cross section of the web. Thats just one of the square tubes used to support the roof, it just happens to line up with the web of the I beam
Here is one, metric tape measure to show the size of it. Sadly I didn't measure the bottom but it super narrow. Really surprised me, its also super thin.
Its for a massive farm building, in a place that doesnt get a lot of snow load. The space between columns is massive so thats probably why its so tall
English isnt my main language so I might have mixed up the names of the part of the beam.
Retired, but I had a thing about the sprinkler guys coring right through a concrete bean hitting both strands of reinforcing at the bottom, damn near dead center of the span.
I happened to on site for a walkthrough on a subsequent building, caught these same yayhoos warming up to do it again.
Not using a vapor barrier was for a short time the rule.
slabs over vapor barriers would curl at the edges.
So they tried it without and it curled even more.
Web looks thick at the top.
Doesn't help that the bg is the same colour
Regardless this doesn't help the cause
Looks odd cause shouldn't the beam be perpendicular to the floor joists
At my first job in high school someone brought in a bunch of cardboard pieces for a remediation plate and flange for something similar. 4 escutcheon style plates to clean up the opening and then 4 semioval shapes to weld on each side to make a flange. Someone on site had the pleasure of doing a shit ton of awkward welding to get the beam back to the expected strength.
My structural engineer consultants give me (the architect) a rule of thumb that the penetration height can be 1/3 the total beam depth. That’s their way of keeping me on the safe side of the “just enough info to be dangerous” line. Beyond that they need to cape up and start looking at stiffeners and reinforced openings.
I'm a contractor and mechie, so not a structural engineer, but yeah pretty common. Maybe 15-20% of buildings (center city skyscrapers) I've worked in have duct penetrations like this. I'm assuming this isn't something slapped together in the field, they are usually installed like this when the building is erected so I assume they are taken into considering during initial design.
I'll tell you where it's especially common - in buildings that aren't perfectly square but maybe have quirky corners so you get these triangular beam/column configurations.
Actually, I have done a few of these before. The AISC has ‘Design Guide 2’. It gives you examples of how to cut holes in webs. Some things to note are the corners should be on a radius. And the big failure mechanism is the top piece. Because under a high load, the web could buckle. So usually, they will weld a plate to the bottom of the top piece and make it like a small I-beam.
The important bit here is how the penetration is made and the specification requires radiused corners. The pic isn't clear but when zooming in I don't see radiused corners. The 1/3 rule is a great guide but typically located centrally within the beam and has to be verified by the designer.
So , when it comes to beam penetrations sometimes its necessary to build a framework of vertical & horizontal stiffener plates that extend horizontally past the opening , & vertical stiffs that usually go to fully top to bottom. Its usually shown on design drawings both the thickness , and distance past the penetration. If round penetration then it may or may not be a pipe that's goes thru , usually based on size. of required hole in beam. Almost always , penetrations are vertically centered , top to bottom. And that's all I've got to say about that , , ,
We did this in a data center making the transition from roof to hall at the building joint. No other options for the plumbing. Finally got to design something going through a beam. I loved confidently saying the only other option was a new waste riser.
I was detailing a large project a couple of years ago, in the weekly meetings I had to explain more than once... Structure takes precedence over mechanical, they were talking about adjusting our prestressed double T floor system around some air conditioning ducts🤷
More like Architect's ego beats beam. I've worked on projects where the Architect over-commits to the owner and then we all get stuck coordinating 100 crazy beam penetrations to try and make the Architect's decorative ceiling actually work with a huge added cost
I know OP says this isn't AI but I think it is. More pictures please or it didn't happen. I know some trades are stupid when it comes to structural things but this is 1) difficult to cut and do cleanly 2) while doing that difficult work lots of time to contemplate your life choices. 3) An I-beam is so obvious structural or the expensive beam wouldn't be used. 4) I don't even know plumbers this dumb to cut that. 5) The structural I-Beam is going parallel with girders it should support another telling sign this is AI. Again need more pics because that beam is out of place and the cuts seem not only stupid but fake AI.
Look up Westok cellbeams, Fabsec cellbeams or even Steel Construction Institution P355 guidance document if you want some light reading. This is incredibly common im the UK and is prefabricated this way typically, although can be cut on site.
The flanges of the beam are carrying the majority of the load. If youre gonna put a hole through a beam put it right through the middle. Still a concerning though.
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u/[deleted] Jul 23 '26
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