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They thought the beam continued both sides so the added a keyway then patch it after. I bleed concrete. Edit: a engineer pointed out this is likely holes left over from PT cable tightening and I think he's right.


Mud in mud out


This dude concretes


Hell yeah brother


This dude knows his shit


That there is what I call architecture feature because bro I don't make mistakes.


I think they just needed to patch the stressing pockets for the PT in the beam, but hey, I’m just an engineer here 🤷‍♂️


That makes even more sense!!!! I tip my hat to you. I have the luxury of not dealing with PT cables


But do you bleed concrete?!?


Yeah I was trying to figure out what the keyways would have been for that the other commenter was saying. If they did have it set up for a beam to come out that side of the column, there would be a lot more evidence than this left over.


Ehh are you sure? Head patterns don’t look like typically. I have never seen them close to the edge (blowout issues) or at the same elevation of the bottom of the beam.


They look an awful lot like the [Beta](https://beta-technical.com/beta2018/wp-content/uploads/2018/12/Flat-anchor-0.jpg) style PT heads. The deck is also like 6-8” which would be a fair bit of rebar necessary if it were just reinforced mild.


Interesting I have never seen those


What’s a better parking garage, cast in place or precast?


We've only done one parking garage that had a lot of precast and it was an f'ing logistics nightmare. It was at a live airport so the site was already a B.


I hate working at airports. We repaved Innsbruck Airport, a small one, it was completely shit down, still a effin b to work. No time, tons of work


But did you have access to schnitzel for lunch breaks?!? I live in NY by JFK Airport, and I can tell you…WE DON’T HAVE SCHNITZEL AROUND HERE (but we have pretty damn good pizza…)


Ye we got Schnitzel twice lol. And idk whenever I see american pizza it grosses me out idk lol Italian the only way. Thin and crunchy crust


As an aviation fan, that is one of the coolest airports/approaches in the world


Oh yeah for sure. Especially when you turn over „Mutters“ to approach for landing, very scenic and beautiful. Need a skilled pilot too because its a short runway only 2km which is about 1.4miles


I've done all kinds of precast. They're a dream if every single level of your project has people involved with experience in it. It's changing how we do construction in an awesome way, but yes, can easily become a nightmare


Cast in place.


Cast in place seem more permanent, precast they get those up soooo fast.


Not a professional in this area but I would assume cast in place would naturally be the best choice, but I wonder if it introduces more room for human errors that could compromise its integrity in the long run


But you are still following a set of plans, and before something is poured the foreman or supper checks it out.but with anything human error is possible that's when you get a early paycheck.


Yeah the Berkman Plaza garage collapse in Jacksonville was a perfect storm. Inadequate design Inadequate inspections No follow ups on deviations observed Early removal of shoring. Amazing only one person died when it fell.


Is that the one where the slab was not connected to the columns, no rebar or capitals and the slabs fell and collapsed 3 or 4 floors.


They were pouring floor 7 or 8 and it collapsed. 30 or so workers rode all the way down and survived. Only one killed was cleaning on the floor below. They had some ramps missing rebar and the whole thing was under-designed.


I think I saw that on TV, if that is the one,they poured the deck on top of the columns with nothing but the concrete for connection no rebar. Crazy.


Here is the report from OSHA. Main contributions were design and early removal of shoring. https://www.osha.gov/sites/default/files/2019-12/2007_12_06.pdf


Just anecdotal, but in the first precast building I worked on, the floor panels were poured with the wrong amount of PT cables so the camber was too great in the slabs. This resulted in the floors being too high, so they ended up having to essentially take a very large portion of the building apart and re do like 47 panels. It was an absolute nightmare. All the precast buildings I’ve done have been difficult, I very much prefer cast in place!


Wild how people’s experiences can vary so much. I just finished up three precast aquatic centers and disregarding the insane level of upfront coordination, they were by far the easiest, most well-coordinated, quickest projects I’ve done to date. I’m a big proponent for precast but I’m sure the experience level of the precast supplier and erector plays a huge role in that.


Yea this particular precast supplier had some problems in the past with other issues as well. They got bought out by a larger national company that we recently worked with and that building actually went up insanely fast with no issues.


I’ve done quite a few projects with Coreslab and have always had good luck. Can’t say the same for a few smaller manufactures though!


It totally depends on who’s doing it. Are the erectors familiar with precast, are the engineers proficient in it, are the manufacturers well established and experienced, do the architects have reasonable expectations with it. If any one of those is out of the loop it will be a nightmare.


Equal amount of human error.


Ever Since the Tropicana Atlantic City disaster, I’ve been slightly suspicious of cast in place.


I worked 40 years building hi rises first 20 form carpenter, much more control, better than few welds.


Can you elaborate brotha? I was just there pouring on the roof like two days ago 🥴 6th floor not the garage




Wow that’s insane


5 killed and $100 million settlement


Somehow they manage to save the rest of the garage


The collapse was in 2003 during the $300million quarter expansion.


As an engineer I gotta say I generally prefer cast-in-place. I can’t really inspect a pre-cast system, I can only take the manufacturer’s word. But when I can go to site and see the rebar, how it’s tied, how much effort they are actually putting into the workmanship, I am much happier to put my name on it knowing it was done well. I can also request some last minute fixes with an angle grinder and a few 15M bars before the pour, sometimes actual *changes* when the erectors notice mistakes that I (or the architect) have made. No way to make any changes when getting a new pre-cast elements would put us waaayyy behind schedule.


Where you shocked when the Trop collapse happened? (Assuming you are familiar)


Not familiar, but not the slightest bit surprised. There are shoddy construction companies, lazy engineers, minimal inspections, and corners cut on every project. I don’t let anyone get away with trash work, but I know lots of engineers that do.


I mean this site seems like they forgot some major stuff….I’m just shocked the whole project didn’t come down. This place is HUGE. 2,400 parking spaces on top of a 4 story mall with a 33 story hotel on top of the north end of the garage with 500 rooms Edit: I guess my question here is what prevented the collapse from progressing into the rest of the building?


My guess is because it was during construction, it looks like it wasn’t all completely connected together so the part that fell didn’t pull the rest down with it. I can find too many pictures of it, or reports detailing the structural failure, so that’s just a guess.


I read a report the collapse was caused by missing connections in the 5th floor from the slab to the walls ‘


We used to work on them. Had an architect tell me that they plan on a precast garage lasting 35 years and a cast in place 70 years. You can obviously get more if maintenance is done and all that but that was what the architects figured. This was at a college if it matters and it seemed they were always doing construction and moving things around. We did 1 precast for them and 1 big cast in place.


Here’s another precast garage in my town that they just finished demolishing and claim they will replace with a sex story garage with 4 stories of housing on top. https://youtu.be/CsMAgvg51n8


Can you tell us more about this sex story you speak of.


That’s a different subreddit lol 😂


It's on r/fuckcars where we complain about sex stories for parking cars instead of sex stories for people's homes.


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Here’s my town’s newest precast garage… First one in 35 years. https://youtu.be/1TBFGQfgGgk


Almost all of the parking garages I've worked on have been cast in place. And as someone else said, they tend to last longer


Cast in place. It's the only way we can change things on the fly as we get issued changes the day before we pour and the day after.


Depends on what you're trying to achieve and where you're building. Assuming everyone knows what they're doing in both cases, precast goes up faster and reduces your dependence on tight concrete truck scheduling (if you're building somewhere with bad traffic and a distant concrete plant this can be a real PITA). It still sucks if your truck is stuck in traffic, but sitting in traffic won't ruin a precast beam. Cast in place tends to have a longer design life and is easier to change during construction.


I’ve only ever seen or been involved in cast in place. Precast I’ve only ever seen for the outside of buildings. How do precast beams sit on and connect to surrounding slab / wall/ columns. Are there parts that are poured in place ? Or do they just maybe support / connect to less things ? Sorry not an extremely experienced guy so the idea is confusing me!


Structural components go together kind of like legos, with the components resting in keyways and they can be bolted, welded or have reinforcement span the joint and it's grouted. If they're post tensioned, internal ducts are cast into the components for tendons (steel cables) to pass through. The cables are jacked to a specific tension and a "lock off wedge" (a steel plate) locks them in place keeping them tight, then the ducts are grouted. You can have designs that are basically all precast or a combination of precast and cast in place (hybrid), it all depends on what you're trying to do. Sometimes you want a big monolithic piece, so CIP would be preferred, sometimes you want an unusual shape in a difficult space to work in or form up, so precast would be preferred.


Right ! Like “core slab” has the holes for the tendons ? Thanks for the explanation


One isn't inherently better than the other. Both have advantages and disadvantages, and it really comes down to the detailing which one will turn out to be a better value in the long term.


Precast is cheaper, cast in place is better.


OldTrapper knows what’s up


I can feel your dry hands from here


I’m a Struc Engineer. The placement doesn’t seem correct for Post Tensioning. Wish there was a pic of the right side of the column.


After 500+ im changing my thoughts. This type of beam would have to be poured over the walll or with it but not after using a keyway. Definitely PT


You sound like a crusty old union concrete carpenter


You didn't even get the last part right lol. I'm a subcontractor working for a subcontracted company as layout guy being pimped out to a third company. Greasy as fuck but not not crusty.


To me, it looks like they thought something was wrong with it and tried to fix it or something like that


Yes a keyway is a hole left to join on to later but they had to patch the hole and now it looks like this.


This it


Should probably get that blood checked out, that sounds bad.


Hey, legend, whatcha doing,?


Concrete for the concrete God! Cement got the cement throne!


Is it true you concrete guys get it hard every day?


Secrete concrete? Typically PT cables are through slab, but perhaps this is some sort of variation? I liked your first explanation better.


Kinda looks like a fuck up. "Oops we missed a beam let's just bolt it on after. This could also be some pre cast work of some weird type.


That's fuckin sexy


A legit sexy 😉 Or it’s a six~y on a scale of ten~y Op has a story up there about the sex story being built.😳🤣 I’m like op is so used to saying sex when six should be ,his phone even knows how to auto fill for him 😬


Why is this tagged nsfw


Idk how that happened


My guess is you clicked that tag


When you see any link that says "NSFW", it's hard not to click on it.


Jenga, but hard mode


It kind of looks like post tension infills. After they tension the cable in that beam they go back and grout in the end of the cables. Those holes are often round though


Looks like cabinet joinery or something.


Could be patch repair after PT cables are pulled.


I've studied pre tension cables in college but for some reason thought they were a myth. Do people use prestressed concrete?


Cast in place usually post tension. Precast usually pre tension. At least in California.


In parking structures most post tension. I have done the precast type. Precast put together like Legos then a topping slab to connect it all together.


Post tension cables are in there and they grouted after.


My mom used a pencil and the kitchen wall to track my height, this is extreme


Maybe they misplaced the block outs for the cable railing?


Post tension grout holes…


Kind of looks like hands playing rock, paper, scissors to me.


I'll have whatever drugs he's having


Bath salts washed down with a paper bag of spray paint


Put the wire rope fittings in the wrong place?


bad stuff mostly


not nsfw


Post tension heads. It’s where they stress the cables to put them under tension. Then grout back the heads.


A demon wrapped It's filthy hands around it and tried to fuck it.