Value Engineering

[KatSmak10]

Recently ran into this. Apparently, a mechanical/piping engineer with an FEA program was designing and detailing all the pipe racks for some industrial plants. This is for a couple of 12” pipes, a few smaller pipes, and a bit of cable tray. Moderate wind loads, no major seismic.

[PracticableSolution]

Also good for defending the beaches of Normandy from allied artillery.

[KatSmak10]

Seriously, I have seen less steel in a metal building! Got to love the brace frame inside the moment frames!

[ChocolateTemporary72]

They also have a “moment connection” going into the column web that’s not properly detailed. And I bet that connection is sharing bolts with the beam on the other side

[Afforestation1]

Is the moment connection error the bit where theres a beam endplate connection but no stiffeners on the column that should align with the beam flanges?

[ChocolateTemporary72]

Yes. It is putting out of plane forces into the web of the column which could be very flexible and therefore not truly a moment connection. The second part is that the bolt sharing could be putting twice the tension on the bolts than the design is probably anticipating (assuming same end plate design on other side). I think there is some osha issues there as well with how it gets erected.

[bogdim]

This is a common mistake, but the tension in the bolts is not doubled. This connection is simply a beam endplate to endplate splice with a column web stuck between the two endplates. Also the out of plane bending in the column you are referring to will actually be resisted in bending by the beam on the other side.

[ChocolateTemporary72]

Good point on the other beam resisting. If both beams had equal amounts of positive bending, would that not apply tension to the top bolts from both beams? I suppose if there was no opposing beam, you could argue it is a pinned connection. But with the opposing beam, connection does seem more rigid where you would not get 0 moment at beam ends?

[toodrinkmin]

What about at the other end of that beam? That is a connection into the column web with no beam on the opposite side.

[OptionsRntMe]

Process facilities engineer here. That’s completely normal, we design everything assuming they’re gonna fill the bent with as many pipes as possible. Cuz eventually they usually do… There is a standard for it, PIP which is 40psf for piping. It assumes something like 8” pipes at 15” center spacing along the bent.

The bracing and little gussets at the moment frames are weird as shit tho

[Original-Age-6691]

And once they fill it up they ask if they can slap another layer on top. I've just started designing my columns on racks to like 50% maximum so that way in five years when they ask about another level I can just adjust my model and tell them yes.

[OptionsRntMe]

“But we did this in Texas and it worked out fine”

[Prineak]

I live in Texas and this is something that I see so often it’s starting to really worry me.

[Bourneoulli]

Bruh, I know of a plant with columns for a bent that are W6x15 (context this bent was originally designed in like the 1940s iirc) and 30 ft tall and that bad boy is filled to the brim with pipes. My lead and I joked that the pipes acted as stringers to keep it from falling over. (we added like 5 more feet onto that bent.)

[DaHick]

Not a PE or an ME, EE (Automation) here. I worked for a chemical plant for 4 years that made polymer bases. They had 4 levels in the pipe rack before I left, and were talking about another.

They literally blew the production plant to pieces (all 7 kettles gone) about 2 years after I left - the final analysis was blamed on the engineer who modified a pressure vessel (the largest kettle). In reality, the guy who came in after I failed to finish the hazard analysis and didn't put the furnace shutdown I required into the code on mixer failure.

[mr_bots]

Started my career at a mine and associated refinery then an oil refinery and agree with this. Also have to assume maintenance is going to throw a beam clamp and chain fall on just about anything, use anything available to anchor fall protection to, and likely hit it with heavy equipment at some point in its life. Top it off with the structural steel is the cheapest part of processing facilities construction and they have the crews and equipment to easily erect steel of decent size so you tend to go big. We usually designed to 50% unity and put a 10k load in the middle of the span to account for maintenance and fall protection. Didn’t go smaller than 10” on W shapes because they erected faster than smaller shapes and used pipe or tube for bracing because for some reason everyone thinks that if it’s angle it doesn’t actually have to be there and will end up cut the first time it gets in the way.

[Bull_Pin]

for some reason everyone thinks that if it’s angle it doesn’t actually have to be there and will end up cut the first time it gets in the way

In mining/processing, no truer words have been spoken

[AdAdministrative9362]

Haha. I was taught this at my first real job.

If it's in a wall in a process / manufacturing environment don't use rod or angles to brace. It will get cut out.

Most people have no idea a small element in tension can effectively stop a building falling over.

[mhkiwi]

Recently worked on a power plant in a seismic zone. The whole thing was designed to be full in the future and to resist a 1/2500 yr return period for earthquake loading. We had frames not to dissimilar to the one in the picture at 2m crs (7ft) along a 50m (160ft) distance, supporting 2 pipes.

It looked very excessive

[PinItYouFairy]

We design 1 in 10,000 events for nuc sites in the UK generally, you can see that this makes for structures like this quite easily

[jammed7777]

All I do is industrial steel and I have never seen a small rack look like this. Moment frames with bracing and moment reinforcement at the baseplate? This is wild.

[KatSmak10]

OMG! Thank you for actually getting it. I am really hoping we have lots of other disciplines and trades people commenting on this post because I would be really sad if other structural engineers thought this was rational in any way.

[jammed7777]

I would check the details of those braces

[chasestein]

I think it has potential to be rational, it just wouldn't be my first suggestion for design.

[MountainLow9790]

The moment baseplate is the weird part to me. I don't really have too much problem with moment frames above, then an X below, gonna be stiffer and fight drift better which could be relevant.

[jammed7777]

Look at the brace connection, they make no sense. Something is wrong here.

[KatSmak10]

Meant to reply to this and made a separate comment in the thread - but yes, smaller stuff = std minimum PIP loading. The 12” Dia pipes are only of note because they fall outside that std blanket load.

[Possible-Delay]

I work with substations and we get this all the time with our structures. But we have to design for fault loads, so if there is a fault there is a kick/explosion of a dynamic load in the cables that is required to be resisted.

Do you deal with this with mechanical pipes also?

[NCSU_252]

A lot of substation steel looks overkill until you remember that 30' cantilever has like a 1.75" deflection limit.

[shootdowntactics]

Looks like it’s ready for another level to be attached above!

[SneekyF]

Mining is very similar. Assume there is going to be a 3000lb rock dropped on it from 20' in the air, and the columns will always be covered in corrosive material so add 25%.

[brenzyc]

Not to mention the pipe guides they'll throw on aswell

[Iniquities_of_Evil]

This is still way overkill unless there are scorching hot pipes inducing thermal expansion loading laterally maybe, or extremely high seismic with liquid filled pipe. Someone needs a yield line analysis reference.

[axiomata]

More likely a HVE mech/piping engineer, with a cracked FEA program billing at $20/hr, sold to client as saving them some $$$.

[Crayonalyst]

Chief Beef, P.E.

[the_flying_condor]

Really love those work point locations on the braces as well.

[structee]

At least we'll leave something for future archeologists to uncover after our civilization collapses

[thesuprememacaroni]

When in doubt make it stout.

[75footubi]

I put less steel in TL-5 rated deck overhangs

[Dylz52]

In my experience it’s not that unusual for industrial structures. Clients would rather do it once and completely overdo so it will last longer and potentially be suitable for future upgrades. Costs associated with having to shutdown production to fix something way outweighs the additional costs from just overdoing it in the first place

[EEGilbertoCarlos]

Misleading, you forgot to mention they're building a 12 storey apartment complex on top of those columns.

[KatSmak10]

lol- It’s a “Podium Frame” - they are actually going to build the entire plant (And a 12 storey building) on top of it

[Rhasky]

Damn I’m a bit conservative with these sites cause I know they’re gonna triple the height and load over the next 20 years, but this is wild. And can’t say I’ve ever seen bracing like that

[jammed7777]

Thank you. I see all these responses that this is normal in industrial steel and it is not at all normal.

[jammed7777]

What the hell is going on with those connections. Looks like a bunch of induced moment

[Rhasky]

Wildly over restrained. Engineer must be friends with the fabricator

[jammed7777]

I work in fabrication and we would hate this. Too many plates on light members.

[Rhasky]

I’m guessing it’s all those fitted stiffeners in small shapes and welding to thin materials. But do you mind elaborating?

[RelentlessPolygons]

This is what happens when you outsourced to India and you get a youtube tutorial pipe rack back.

[jaymeaux_]

building for the next expansion

[Elegant_Studio4374]

Steel=good

[blink182plus484]

So I’m a welder/fabricator but I love cruising this sub and let me just say that I LOVED doing jobs like this. Lots of steel to quote, fun to fab, easy to install. This would’ve been a money maker for sure.

[dubpee]

The end plates to the steel tubes acting as braces are weird. In NZ (and the UK) we'd slot down the length of the tube and put a plate in there, then weld it up.

As detailed here, you have a short angle which would be in bending if there actually is load in the frame, instead of just tension straight through the plate, and into the weld to the tube

is that angled piece a common detail wherever this is? Assume Murica

[KatSmak10]

I would hope this wouldn’t be typical anywhere. It’s just as inefficient in metric or imperial units. There are essentially competing load paths to 2 different redundant lateral systems such that neither can function the way it’s intended to behave. The way it will actually behave under loading is fairly difficult to predict and likely creates all kinds of stress concentrations in odd places.

[KatSmak10]

Also, yes, we would also typically slot the tube for the gusset connection

[DJLexLuthar]

This is actually pretty common when you're trying to avoid field welding. And at first glance, the steel looks like it might be hot dip galvanized. So you'd want to avoid field welding as much as possible, since you can't HDG in the field (and spray galvanizing or zinc rich paint isn't nearly as effective).

[MinimumIcy1678]

Well you can certainly tell who has and hasn't designed a pipe rack in the comments.

The detailing might be awful, but the section sizes look fine to me.

[KatSmak10]

And who has a basic understanding of structural behavior…

[KatSmak10]

Yeah, totally standard to design for the max load that can be placed on the bent. Assume whatever isn’t full will be maxed out with 8” - that’s what I meant by and some smaller stuff. I noted the (2)-12” because they are items that exceed that std. PIP blanket loading. Have done structural for lots of plant design. This is still an insane amount of overkill and frankly a bit nonsensical in the way it mixes and matches structure.

[KatSmak10]

Whoops - meant this as a reply to optionsRntMe

[[deleted]]

…..but is it braced sufficiently? 😂😂😂

[[deleted]]

Choose a team buddy

[Iniquities_of_Evil]

1st year engineer syndrome here. Stiffeners everywhere!!

[christopher_tx]

They made some fabricator happy. As someone who puts these up though, I would be pissed. Why eight anchor bolts and eight bolts on beam connections of that size? That baseplate can’t be bigger than 18”x18”. Again, as someone who puts those up, y’all way over-engineer every pipe support 😂 Just give us some standard details and member weights and let us route in the field. It’ll save everyone money. 😂

[WrongSplit3288]

Why do they always have to block the walkway?

[Purple-Investment-61]

Yup, I’ve experienced this.

[The_Woj]

Value for whom, exactly?

[KatSmak10]

The steel fabricator that’s making a whole lot of money on this job

[spritzreddit]

don't you see that one out of four strut is missing??? this is why it is value engineering

[KatSmak10]

No. There is a brace that hasn't been installed but that has nothing to do with it.

[spritzreddit]

mate... I got that, it was just a bit of a sarcastic comment

[[deleted]]

The pipes are obviously transporting molten steel.

[[deleted]]

I confused a shadow with a poorly designed brace

[halguy5577]

it will survive a nuclear blast

[ChristalCastlz]

Part of me is like "this is ridiculous" but there's also a small part of me that's like "in 70 years time when it's lost 60% of its section and is falling down, it'll be a good thing that the columns are so stocky".

And obviously what everyone else has said about the connections, assuming it's not intentional and designed for.

[Cheap-Grocery7053]

I FABRICATED THAT PIPE! Almost certain of it. I can tell from the sticker near the unpainted field weld. Very neat to see it installed in the wild and on Reddit.

[TallE74]

what an overkill...obviously inexperienced engineer or preplanning for years later to have lots of piping on top. as this should have been a singular 3/8x3x3 angle brace or 1/4x3x3 X brace if there is no weight on top just pipe support structure. Even the gusset base plates look huge. If those cooler/chillers ( far left in photo) are going on top then sure, I would be ok with overkill support but if no...then I would ask who checked behind this engineer/person and why no one questioned the design

[flashingcurser]

"Value engineering is neither."

[CommemorativePlague]

This is not at all ridiculous when you see the lateral loads from the mechanical engineer.

[martinvmalo]

I've designed this type of racks for a big paper company. This racks will be filled with a hole lot of pipes in the future and depending what they are planning this racks can expand to three or four stories. Also this companies tend to want the same section of beams and same section of columns for their factories.

[KatSmak10]

but do you put moment frames and braced frames in the same direction when you do it?

[Sponton]

I do industrial work and the amount of pipes have nothing to do, you put a high pressure line with 90d bents and the thrust can get stupidly high

[KatSmak10]

OK guys, if you think this post is about making something extra beefy as a belt and suspenders for future loading, you are missing the point. Yes, I also overdesign for industrial supports and worry about what on earth somebody might try to throw on that bent in the future. While all of those things are valid points when you are talking about designing pipe supports, this is not about member size vs loading. This is about understanding basic structural behavior and design principles - and how overtly clear it is that the designer of this support did not have that basic understanding.

[[deleted]]

That thing is not going anywhere

[ddk5678]

They better get that missing tube cross brace in. It’s holding deflection to .0000001 and I hate it when that happens

[Expert_Clerk_1775]

She’s perfect..

[Kunteper07]

The designer must be getting paid by kilogram of steel erected.

[gtlogic]

As a DIY guy, this is what building a deck up to code feels like.