floo

Ministry of Land: So Seoul, you're saying we can use half the rebar from now on? ^^

🦊
·9 days ago

원본 (Korean)

Translation + Context

FT = ForbiddenTome — tap to see Korean slang explained

Charm of the East Sea

Seoul Special City

Special City Seoul

Seoul City "Safe even without reinforcement"... "Only half going forward?"

"Safe even with half the rebar?"

Donghae · Attractive Special City Seoul

Seoul Special City

Youngdong-daero Complex Development Basement 5F Pillar Site

Star of Seoul

Seoul Special City

Seoul Special City

Acting Seoul Mayor "Safe even with rebar missing"

"Half the rebar—is it 'safe'?"

Kim Sung-bo / Acting Seoul Mayor I was referring to Seoul City's judgment that, according to the design method recognized by the state, it appears to be safe.

MBC News Desk

Half the rebar—'Safe?'

Pillar strength (KN)

Strength reduction coefficient applied

Material coefficient applied

Required strength

59,349 Met

Not met

[Seoul City]

Special City Seoul

MBC News Desk

"Is it safe with only half the reinforcing steel?"

Dongdae-ro Underground Space Complex Development Section 3 Construction - 5-Story Column Load/Strength Comparison Table

Condition After Reinforcement

Current Condition

• Seoul

Column Strength (KN)

Column Strength (KN)

"Strength

Single Row Rebar Placement

(Load) 1)

Single Row Rebar + Steel Plate

20 Rebar Placement

Strength Reduction Factor Review Material Factor Review

Recently 1 Day Omission Reflected

Material Factor Applied

Strength Design '(Strength Reduction Factor' KDS 14

Design Method

Strength Design Method (Material Factor Applied) ₩ 2020 Appendix

Kim Sung-bo / Acting Seoul Mayor

Even though the rebar was omitted, according to the design method approved by the government, when originally placing 2 rows of rebar, equivalent strength is achieved.

"Half the rebar and it's still 'safe?'"

"Slab cracks unrelated to missing column rebar"

MBC News Desk

"Safety?" Even with half the rebar

East Sea · Charm

"Seoul Metropolitan City

Metropolitan City Seoul

Power

Charm

Seoul

Kim Sung-bo / Acting Seoul Mayor "Structurally there are no safety issues" - so that's how you write the article, right? Because the part where rebar was omitted is clear.

MBC News Desk

'Safe with half the rebar?'

East Sea charm

'Seoul Special City

Special City Seoul

"Charm

Sea · Charm

Seoul

Kim Sung-bo / Seoul Mayor Acting Authority There are anxious psychological aspects, and in terms of completing what was originally designed, I think it's appropriate to implement reinforcement.

National Railroad Corporation Emergency Safety Inspection Results

Structural stability ㅇ Multiple cracks confirmed in the basement level 5 slab, but mainly assessed to have high possibility of non-structural cracks such as mesh cracks due to drying shrinkage. However, some sections show continued water leakage even after crack repairs, raising concerns about long-term structural durability deterioration, so continuous monitoring and repair/reinforcement of cracks and water leakage is necessary. ㅇ Test train passage vibration level 0.04-0.07kime, due to construction errors the design strength of the columns was not secured, even after opening around 60krrrrr adjacent construction, the structure requires urgent column reinforcement ㅇ Currently the structure is in the construction stage where full superimposed loads are not all applied (B3 layer under construction), but due to construction errors the design strength of the columns was not secured, so urgent column reinforcement is deemed necessary. Furthermore, structural review considering current conditions and load conditions by construction process stage, etc. is necessary to secure structural stability □ Column Reinforcement Plan ㅇ Reinforcement for axial force deficiency due to column rebar omission can consider section expansion method or steel plate reinforcement method, and Seoul City (Constructor Hyundai E&C) is proceeding with reinforcement direction as steel plate reinforcement + epoxy filling + fireproof paint through consultation, etc.

MBC News Desk

"Safety with half the rebar?"

Ministry of Land, Infrastructure and Transport Official: "Seoul shows a lack of safety awareness. Going forward, does that mean we only need to use half the rebar in all designs?"

What are you talking about? You're spouting nonsense x seriously so annoying

 

 

 

11 comments

🐰

I thought just having more rebar doesn't necessarily mean it's stronger... But if rebar is so good, why not just shove in one solid 50-ton steel plate? That'd be the strongest, right? Steel is definitely tougher at the same thickness, but... anyway, from what I know, the important thing isn't the rebar itself—it's the concrete. Rebar's job is just to hold the concrete together and keep its shape. Like little sticks supporting a grape vine.

🐿️

Yeah, but they removed half those sticks lol and while more isn't always stronger, the design is calculated based on what you use. If you're missing 50% from the design, that's already not normal lmao

🐰

No I don't know either, dude~ My field is nuclear engineering and concrete/rebar stuff I've only learned from flipping through FSARs by accident. So since you actually know, explain it to me

🐰

It's not that I know a lot—it's that the absolute nonsense Seoul is spouting is so dumb even someone like me who knows nothing gets it. What company plans their whole structure and then goes "hey, nobody can see this part so we can skip it" and announces it's fine? Nothing wrong with that? And it's a 5-level underground subway so the structural integrity is even more critical? Now even the Ministry of Land, the top dogs in construction, are like "stop spewing nonsense"

🐿️

It's scary because if they're cutting corners on rebar, there's no way everything else is fine

🐰

So why are you running your mouth about danger without knowing how dangerous it actually is? lmao? If you can't explain and just repeat obvious middle school level stuff, shut up dude~

🐰

So what do you know that you were talking about? Explain why removing 50% rebar isn't dangerous? You're stupid talking nonsense without knowing anything yourself lmao

🐰

I never said it wasn't dangerous, you idiot? lmao I'm just curious~ Like, Seoul probably has some engineering-based reason for saying that right~ But it's annoying when people who don't even know anything come in spouting the same obvious stuff a high schooler would say like it's some big deal, you know?

🐰

If it was sound engineering, the Ministry wouldn't be bitching about it lmao. Wa-O apartments, Sampoong, Seongsu Bridge collapsed because they were sound right? lmao? Underground subways are designed to handle vibrations and everything, but you're saying that removing rebar is fine? Are you the one removing it? lmao

🐿️

Oh the Ministry of Land said this~ the Ministry of Land said that~ the Ministry of Land didn't say that~ No I don't care about this crap, you idiot, just shut up. I don't even know if the Ministry of Land is your daddy or god or whatever, I don't care about that—

🐰

If removing 50% is safe then why didn't you design it with 50% less from the start, you idiot? You should've designed it with 50% less from the start and then gotten safety approval and proceeded like that, you moron

🐰

Yeah the Ministry of Land says it's safe so die then lmao. I'm not curious about that stuff, I'm just curious what these guys are saying and what it actually means~ ㅉㅉ Thickheads lol

🐰

Rebar isn't just for shape—it's for tensile reinforcement. Concrete is strong in compression but tensile strength is laughably low, so rebar does the heavy lifting there. If pillars are missing tons of rebar, compression might be fine but tensile resistance to bending moments and buckling would be way reduced. Saying it's equally safe is suspicious—if that were true why design for 2x in the first place? lmao

🐰

But if it's a pillar, doesn't only compression act on it anyway? So buckling becomes an issue? But concrete isn't a ductile material so how does buckling happen?

🐰

Buckling happens regardless of material properties if the structure is long and thin.

🦊

Like, does it actually bend? No wait, I don't need to ask this. If there's buckling and it's not ductile, it'll just shatter trying to stay rigid. But adding rebar doesn't make concrete ductile, right? So it's purely just adding structural stiffness?

🦊

You should die if Seoul says it's safe lmao. When have politicians and bureaucrats ever not made excuses and spouted nonsense? If 50% of the rebar is missing, we should check if the concrete and sand actually went in right too, and they're spewing nonsense properly lol

🐿️

You've never thought about earthquakes? Even the slightest lateral force makes tensile strength more important than compression

🐰

Your mom ^^

🐿️

Oh yeah, seismic design would definitely be a problem

🦊

Earthquakes are just a small part of it. Vibrations from vehicles have the biggest impact. It's not just vertical vibration. Unreinforced concrete has a really low threshold for collapse under lateral force, so to speak

🐰

Yeah with that much weight, even just the subway passing through and twisting things around has a big impact. Thanks for explaining

🐰

You know what's really scary? They say they're reinforcing with steel plates, but even if you reinforce with steel plates forever, a steel-reinforced concrete structure won't have the same tensile strength

🐰

If you think about it, steel plates don't bond well because tension/deformation isn't isotropic... But if they're driving in steel columns, I dunno. But then they would've just installed temporary supports, so there must be a reason they didn't

🐿️

Vibrations from subways and vehicles generate both compression and tension.

🦊

Most of the load a building bears is supported by the concrete's compression—that's right. Concrete handles most of the compressive strength. But concrete's tensile strength is extremely low by nature, so rebar is added to compensate. The safety against vertical loads from upper structures and ground loads is mostly fine even with missing rebar. But safety against lateral loads like earthquakes, vibrations, earth pressure, and groundwater movement becomes weaker by however much rebar is missing. And one of the biggest factors affecting structural stability is the weight of the structure itself. That's why you can't just expand the structure with steel arbitrarily.

🥚

"Even someone like me who doesn't know gets it" lmao the Ministry already got reports last year and is busy passing the blame. Why would you trust what the Ministry says

🐰

Safety written in fatigue

🦊

Used to have something there but deleted it I guess

🐿️

Forgot

🐰

WAIT this is actually terrifying lmaooo are they saying Korean buildings have been overbuilt this whole time??? 😭

🦊

Oh so safety margin means you can cut 50% of the rebar and still be safe... Is there also a safety margin for when they dump 2x the water into the cement?

🦊

Whoa just tell me it's all BS

🥚

No wait, even trucks passing by are designed so 1-ton trucks can carry 1.5 tons, so 1-ton capacity is safe right?

🐿️

Safety protocols are written in blood. This time a storm's coming

🦊

This is either the most Korean thing ever or a massive red flag and I genuinely can't tell which 💀

🐿️

Let a few thousand die then they'll make some special law lmao F

🦊

pretty sure this violates like 50 building codes but go off i guess lol

🦊

Is the acting Seoul mayor something?

🐰

Probably the vice mayor is a civil service exam grad

🐰

as someone who lives in seoul this is NOT the content i wanted to see today thanks

🐰

So you're saying the original design was overkill just to squeeze more material costs? lmao. These guys really let anyone be in society. Tell that guy to drive with half his tire pressure from now on

🐺

okay but if Seoul's been fine with half the rebar, why have the rest of us been doing it the hard way

🐰

bro the emoji at the end makes this sound so casual for what sounds like a structural engineering nightmare

🐰

The sarcasm is KILLING me but also... are apartments about to start crumbling??? asking for a friend