Did I Uncover a $100,000,000 Mistake with the Millennium Tower 'Fix'?

For engineers wishing to perform their own calculations:
Plate Material: ASTM A572 grade 50 (Per SGH Drawing Notes Sheet S001)
Plate Dimensions: 1-1/2" x 6-1/2" x 1'-1" (Per SGH Sheet S502 - 2 Rods per plate)
Rod Tensile Load: 250 kips to 345 kips per rod (Per SGH Calculations Sheet 104)
Concrete Compressive Strength: 7000 PSI (Per SGH Sheet S001)
Revision Date of Referenced Drawings for 18 Pile Repair: 01-13-22 Signed by EOR

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𝙈𝙞𝙡𝙡𝙚𝙣𝙣𝙞𝙪𝙢 𝙏𝙤𝙬𝙚𝙧 𝙥𝙡𝙖𝙮𝙡𝙞𝙨𝙩:

𝘾𝙝𝙖𝙢𝙥𝙡𝙖𝙞𝙣 𝙏𝙤𝙬𝙚𝙧𝙨 𝙎𝙤𝙪𝙩𝙝 𝙥𝙡𝙖𝙮𝙡𝙞𝙨𝙩:

𝙊𝙣 𝙋𝙤𝙞𝙣𝙩 𝙥𝙡𝙖𝙮𝙡𝙞𝙨𝙩:

𝙊𝙣 𝙩𝙝𝙚 𝙅𝙤𝙗 𝙥𝙡𝙖𝙮𝙡𝙞𝙨𝙩:

𝙊𝙣𝙚 𝙤𝙣 𝙊𝙣𝙚 𝙥𝙡𝙖𝙮𝙡𝙞𝙨𝙩:

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Disclaimer: Nothing contained within this video should be construed as legal advice. Building Integrity makes no claims of its own regarding the guilt or innocence or liability otherwise of any legal entities mentioned in any of their videos. These videos are made for news/informational and educational purposes only.

[BuildingIntegrity]

Small correction: The Engineers that designed the "Fix" were not the structural engineers for the original building design. I meant to refer to the engineers of the current "fix" as the "original fix engineers"... not the original building engineers. If you are an engineer and want to perform your own calculations, additional material strengths can be found in the video description. I have emailed the SF Department of Building Inspections and Supervisor Peskin re this concern. I will update you all when I know more.

[philnichols]

I am a retired consulting mechanical and electrical engineer, having worked with architects for 52 years in the design of commercial and municipal buildings. I have followed your YouTube videos and found them very interesting and informative, especially the Surfeside project. Recently I "stumbled on" a short video showing the potential failure of an apartment building for college students in Manhattan, Kansas. After viewing the video I sent an email to the city engineer, suggesting she watch that video. The apartment building was apparently fully occupied at that time. In the email I suggested that the city engineer contact Building Integrity. I did not have any reply from the city engineer. Interesting, the next day or so I saw a news report that the Manhattan fire department had condemned the building. I have not followed up, nor have there been any communications. Thanks for your good work. PN

[garrettkajmowicz]

I have an engineering degree in an unrelated discipline. In addition to that plate (and the associated nuts), I'm also worried about the ability to transfer that much force to the existing building. The existing foundation was designed to have force distributed widely across the base. Putting that much force on the edge strikes me as a great way to run into weird loading regimes including torque, which concrete doesn't handle too well.

[garydavidson]

All parties involved need to face the hard truth that the building should be dismantled completely.

[RockHudrock]

UberEats driver here, If the threaded rods are loaded beyond their yield strength, couldn’t you end up with a cascade failure, once one of them snaps, the load is transferred to the adjacent rod, which snaps, and so on. Kind of like the Francis Scott Key bridge, but underground.

[GeneralBolas]

This really sounds like a holdover from the 52-piling design where the plates probably would have been fine, but then they dropped 2/3rds of them and nobody really thought to check that particular part.

[theharbinger]

I am afraid this project is headed for a monumental NOVA / Frontline collaboration episode in a few years. Thanks for the update.

[adamnoakes]

I am a UK Chartered Engineer (similar to a USA Professional Engineer). On watching your review of the drawing, I have to agree the bar/plate connection looks worryingly small. From your discussion of the calculation sheet, I understand that the bars are sleeved/greased mainly to simplify the design for "fuse" action of these bars (wherein the designer calculates a required "free length" of 160in). The bars could have been designed with a more conventional anchorage into the vault concrete (that is, a connection that can transfer load more gradually, over a longer length of bar), but then "fuse" design would become more complex as the composite behaviour of the bar and the concrete would need to be considered. By sleeving/greasing the bars, the calculation of free length for "fuse" action is greatly simplified, but by inspection all the load now has to go from the bar to the vault via the plate, just as you have explained. I am also concerned by the unchecked assumption that the jack load will be evenly distributed into all 4 bars. If there are any geometrical imperfections, some bars will take more load than others, which is very concerning since the bars are intended to yield at some point. I agree that if the bar/plate connection fails, the vaults and piles are rendered entirely useless. There would also be a sudden change in support to the Millenium Tower itself.

[annoyingbstard]

I’m a professional road sweeper and my concern is that wall might collapse if I lean my broom against it.

[countfrackula]

This tower is the exact case-study of why doing things cheaper is rarely better. If they'd done it right the first time, this wouldn't have been an issue in the first place.

[Geotech]

As a geotechnical engineer that has observed much smaller anchors with a similar design fail while testing them, I am very concerned. If that plate fails the rods could become rod shaped missles which shoot out of their holes through the overlying vault roof. Your analysis needs a response from the design engineers and city building department.

[Richards]

Josh I think that you have identified a valid issue. As a Professional Engineer with 45 years experience, I agree that, just from observation, the size and thickness of the plate at rhe bottom of the rods appears to undersized for the magnitude of the loads proposed. This area requires careful design where you report there does not appear to be any present.

[charliefortin]

The original foundation was insufficient to handle the load. Remediation has proven to be insufficient as well.
It’s time to admit failure and do a tear down before we lose lives.

[mendel]

Your passion for safety is addictive. I have no background in structural engineering but I watch your videos because they are very detailed and informative.

I hope your channel grows.

[HornetVF]

You might want to consider sending this to the Insurance company providing the liability insurance. They could put the breaks on this and force the A&E and Construction company to provide the calculations. Most Insurance companies have engineers on staff.

[stephanieburns]

I am not an engineer, but was a PM who got to see the 4" steel base plates for the Oviatt Library lobby columns sheared right through due to the Northridge Earthquake. Engineers put a lot of faith in steel & the earth doesn't was my takeaway

[Jeffiekins]

I was an engineer for my first year of university (then switched to Physics; go figure), and really enjoyed Statics and Dynamics (basically, the topic of this video). I also taught high school science for a little while. I read a lot of these comments, and didn't see anyone (sufficiently) praise the teaching technique. It was beautiful. I was sitting with the question "so what's at the bottom of those threaded rods?" for a couple of minutes, which made me really pay attention to what could have otherwise been very dry stuff. I'll have to remember this for when I (eventually) get back in to the classroom. Well done! The only downside is that now I have to go watch all your old videos. 🙂

[jstoney]

Spent 25 years as a Structural Inspector (Steel/Rebar/Concrete) on NYC High Rises and I agree with you!

[brianmucha]

I started studying for my engineering degree in 1981. That connection reminds me of the Kansas City Hyatt walkway connection that failed that year. Also, I've discovered over the years that proportions can give a good indication of a potential problem. In this case I see a massive pile, massive reinforced steel beam, massive anchor bolts, and a little tiny plate. Right there I would have asked questions. Final comment, as an engineer we are to try to find economies in our designs. All the components in that cross section, the Pile, the beam, the excavation, the concrete etc. The least expensive item in the whole assembly that stupid steel plate!! I would have sized a simple plate large enough to distribute the load to the concrete and with adequate thickness to resist all the shear loads. Then I would have added stiffener plates and plate washer, and it still would be the least costly component in the design. Then I would go home and had a good night sleep.

[TheSMasa]

As mechanical engineer I would double check also the "tension fuse" calculation. I'm European, so the ASTM F1554 is not too familiar to me with all of their intricacies, not to talk about the units :) But what is perplexing to me, is the lack of taking into account the notch effect in the tension fuses. Those things, to my understanding, are all through threaded rods. The thread has a significant impact on the tension strength of the rod. There is going to also be wind affecting the building, which will cause the building to sway and that will cause the amount of tension in the fuse to alter. The thread with it's sharp crests and valleys will also act as a perfect swarm of nucleation points for cracks under fatigue load. I'd love to see how this is going to play out, but without the people inside or near the building... Do some of those ASTM or AISC things take these into account?

Also your worry about the steel plate is valid, worth some triple checking.