The Fight to Fix the Tilting Millennium Tower

san francisco has a problem one of the city's glittering new skyscrapers is leaning over of san francisco sinking and leaning millennium towers this one worked there's now a revised plan to help stop the sinking and leaning millennium tower the 197 meter millennium tower has at the time of this video publishing sunk more than 45 centimeters causing it to lean 60 centimeters to the west and 20 centimeters to the north despite efforts to correct the issue it's continuing to tilt about seven centimeters more north and two centimeters more west every year if nothing's done the tower could reach a lean of more than a meter at which point according to the building's own chief engineer the elevators and plumbing would no longer be able to function the race is now on to right the skyscraper engineers are installing new piles underneath the foundations of the 311 000 ton building in an attempt to stop it from forever becoming the leaning tower of san francisco but there's a problem there too millennium tower was always due to sink just a little most skyscrapers are expected to settle once construction is finished sinking a few centimeters under the enormous weight of the glass and steel that's above them normally the sinking is so miniscule and takes so long that no one notices engineers estimated millennium tower would sink no more than about 10 centimeters over the course of its life when the tower first opened back in 2009 everything seemed fine the building even won awards for its structural integrity including the american concrete institution award for construction and the structural engineering project of the year demand for its luxury condos was so great the owners were reselling their units at two to three times the price they'd originally paid for them with the penthouse going for 9.8 million dollars it's a wonderful location eight years ago jerry and pat dodson paid 2.1 million dollars for a two bedroom and planned to live out their retirement enjoying the sweeping view from the 42nd floor but it soon became clear that something was wrong in 2016 it was revealed the tower was sinking much faster and further than expected worse the sinking was uneven giving the building a pronounced tilt to the northwest so montana is now suing the developers of san francisco's sinking millennium tower cue a media storm as developers engineers homeowners and the city of san francisco all rushed to blame and sue each other especially when it became clear that the cost to fix the lien could exceed a hundred million dollars so what went wrong well ron hamburger the engineer leading the millennium tower retrofit blames construction work on a nearby site while working on the salesforce transit center construction teams dug an 18 meter hole and pumped millions of liters of water out of the ground hambucker claims that that clearing of water from the soil created an effect called soil compaction where the earth started compressing at a far faster rate than predicted but well before the transit center got going during the construction of millennium towers basement contractors had to pump out massive amounts of water just to keep the area dry no matter who or what is to blame the lawyers will have fun figuring that out and the towers tilting has had consequences growing cracks in the sidewalk and the most shocking what the couple discovered when they visited the lowest part of the garage water appeared to be seeping through the concrete walls and huge chunks of walls seemed to have crumbled away even though the building was only seven years old in 2017 the building was declared still safe to inhabit despite cracked windows walls and sidewalks but something had to be done hamburger came up with a plan to correct the tilted skyscraper 52 additional piles will be put underneath the building placed through the sidewalk and under the building's main foundation these piles would extend beyond the original foundation reaching 76 meters down to the layer of bedrock below that's a process called underpinning and it's fairly common these new piles were intended to even out 50 of the building's tilt over the following 10 years leveling the rest of it out over the next half a century but in 2021 stabilization efforts were halted it was discovered that the installation of these new piles might actually be making the skyscrapers tilts even worse the tower sunk an additional three centimeters contributing to a further 12 centimeters of lean at the top new piles were designed to stop the sinking when they were driven into the bedrock and attached to the skyscraper an operation scheduled for later in 2022 however there are fears the holes that have been dug for the new piles were causing even more soil movement it was later revealed that construction teams had also left a one to four day gap between removing the soil and putting in grouts meant to reduce the risk of soil collapse this delay went against regulations and could have caused further damage [Music] the building does continue to settle at a rate of about one half inch per year and to tilt at a rate of about three inches per year the building remains safe but although the building remains safe we believe the project needs to resume construction and complete this construction quickly to stop fergus element until and to allow some recovery of the tilt as was originally planned that i believe that the building remains safe and in fact can tilt more without becoming a safety issue or a serviceability issue at a hearing in january 2022 hamburger pitched a new plan to save the building engineer ron hamburger who is in charge of the fix is only calling for a total of 18 piles hamburger adds seeking only 18 piles won't provide as much uniform support as 52 piles would have so they can expect less tilt recovery to the north instead of installing 52 piles they would only install 18. these 18 piles would go further than 76 meters and because there would be fewer of them there would be less disturbance to the soil underneath the building the new plan is currently under review and will be decided on by march 2022 it'll likely go ahead but further balloon the cost of the fix from 100 million to 500 million dollars with millions upon millions of dollars at stake in lawsuits this story seems very dramatic but is the millennium towers tilt as bad as it sounds well many tall buildings across the world tilt the elizabeth tower in london which holds big bend tilts 0.26 degrees at its worst the lean tower of pisa tilted 5 degrees although it was later stabilized to fall if millennium tower was leaning that badly it would be tilting a very visible 13 meters at its top as of right now millennium towers tilt is unnoticeable to the naked eye its current lean is less than 0.2 degrees the building's engineers have continued to insist the skyscraper is safe to live in and not in any immediate danger hamburg has claimed that millennium tower would need to lean by more than 180 centimeters for it to be unable to withstand an earthquake a far cry from its current 60 centimeter tilt that said the building would be rendered uninhabitable if the plumbing and elevators stop working and that could occur when the lien gets to 100 centimeters so for the engineers it's a race against time to stabilize the sights one with millions of dollars at stake but this is more than a case study and what can go wrong it's also a reminder of just how robust the engineering of modern mega projects really is massive buildings with low fault tolerances are built on compatible soil in places all around the world and virtually none of them suffer from the problems we've seen here in san francisco and the fact that hamburger and his team of engineers can even try to untilt a 197 metre skyscraper is testament to just how far the construction industry has come let's hope that for millennium tower the third time's the charm if you enjoyed this video and you want to get 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Channel: The B1M

Views: 2,090,247

Keywords: B1M, TheB1M, Construction, architecture, engineering, The B1M, Fred Mills, building, millennium tower, San Francisco, Skyscrapers, leaning tower, leaning tower of san francisco, ron hamburger, california, foundations, ground engineering, salesforce tower, sinking tower, leaning skyscraper, skyscraper

Id: q56dRLI0X7Y

Length: 8min 41sec (521 seconds)

Published: Wed Mar 02 2022

Reddit Comments

[u/ahender8]

I'm over it, tear that stupid thing down already

[u/Runnah5555]

A civil engineering is now looking for a new job.

[u/Al-Anda]

Fucking Millenniums.

[u/Lon72]

Why bother , thre Italians have made a whole tourist attraction out of their leaning tower .

[u/Geo-Nerd]

A far more useful video... https://www.youtube.com/watch?v=OOWn-HMd5Co