The Sinking SF Millennium Tower

[CGI_Ram]

This is an interesting story if you are into this sort of thing…

San Francisco’s Millennium Tower has been sinking, and last year moved 3” on one side. Since it’s construction, the tower has leaned a total of 24 inches to the west and 7.9 inches to the north. It has settled around 18 inches deep into the ground.

This tower opened in 2009. Swanky and expensive apartments.

Its a fascinating story of choices made in the design process. These two videos are well done. Tells the whole story to this point. It is not done.

It is quite the mess as they decide how to fix it. Recent attempts made it worse.

Anyway if you are a geek for stuff like this, these videos are good.


View: https://youtu.be/OOWn-HMd5Co



View: https://youtu.be/gIxhpP7hQu4


More articles;

San Francisco's 'leaning' skyscraper tilted at a rate of up to 3 inches last year

A $100-million effort to stabilize the occupied high-rise is underway, but the leaning may worsen before work completes later this year.

www.cnn.com

UPDATE: San Francisco Supervisor Aaron Peskin Questions New Fix for Millennium Tower

The latest plan to fix San Francisco's sinking and tilting Millennium Tower was the focal point once again of a city-run hearing on Thursday.

sanfrancisco.cbslocal.com

 

[Riverumbbq]

Being someone who has lived in California for the better part of 60+ years, one factor that remains a constant when it comes to design, soil & building technic in Earthquake Country is the potential for liquefaction, and the one way to avoid these settling or destabilization problems is drilling directly into bedrock to set your foundation piles. It actually seems unforgivable imo that in this San Francisco Bay area where sand & wet clay are the primary soil structure to even grant building permits not requiring developers to anchor onto or extend piers deep into bedrock, especially buildings of such weight & magnitude.
Has anyone explained the additional costs of drilling into the bedrock as opposed to what they were allowed to get away with on this project ? Money, politics & corruption seems to always go hand in hand, and by the time they get this matter settled, most or all the principals will be long dead, ... it will be interesting to see who ultimately winds up paying the tab on this boondoggle.
jmo.

 

[CGI_Ram]

Being someone who has lived in California for the better part of 60+ years, one factor that remains a constant when it comes to design, soil & building technic in Earthquake Country is the potential for liquefaction, and the one way to avoid these settling or destabilization problems is drilling directly into bedrock to set your foundation piles. It actually seems unforgivable imo that in this San Francisco Bay area where sand & wet clay are the primary soil structure to even grant building permits not requiring developers to anchor onto or extend piers deep into bedrock, especially buildings of such weight & magnitude.
Has anyone explained the additional costs of drilling into the bedrock as opposed to what they were allowed to get away with on this project ? Money, politics & corruption seems to always go hand in hand, and by the time they get this matter settled, most or all the principals will be long dead, ... it will be interesting to see who ultimately winds up paying the tab on this boondoggle.
jmo.

They could have gone to bedrock for $4 million more during the original design, as opposed to the friction pile foundation they elected to do.

Now… they will be spending waaay more to fix it.

In the 2nd video he explains how friction piles work, and… he makes a good case that it was a miscalculation using this type.

Liquefaction remains a concern but they say the building is stable. It sounds like there are a lot of different opinions on what to do next.

Fascinating.

 

[Riverumbbq]

Wow, $4M is pocket change compared to the end game on what this mess will likely cost to clean up.

'They' say the building is stable, but to just how high a magnitude earthquake should liquefaction occur ?

 

[CGI_Ram]

'They' say the building is stable, but to just how high a magnitude earthquake should liquefaction occur ?

I don’t recall that said specifically. The article states; “the building can withstand at least 70 inches of tilt to the west and 30 inches to the north before its ability to resist earthquakes would be compromised.”. So, another 40” or so it can lean.

The solution they started to implement was installing 52 piles to bedrock, and securing them to the existing foundation. Once the repairs started to make things worse, they now say they only need 18 piles to bedrock. This is where disagreement among engineers comes from… if 18 piles is good enough, why did they originally want 52?

UPDATE: San Francisco Supervisor Aaron Peskin Questions New Fix for Millennium Tower

The latest plan to fix San Francisco's sinking and tilting Millennium Tower was the focal point once again of a city-run hearing on Thursday.

sanfrancisco.cbslocal.com

 

[OldSchool]

Pretty sure there are multiple such buildings in the city.

 

[CGI_Ram]

Pretty sure there are multiple such buildings in the city.

I do not believe this foundation type is unique, so I am sure you are right.

As I understand it, it is number of piles in this case and how close together in combination with the weight/height has lead to more settling than expected.

It was expected to settle 6” total at design. So far, its settled 18”.

 

[Merlin]

If I owned property on the side where it's leaning I do believe I'd be selling.

 

[Corbin]

Any chance they built on the piles of shit that frequent San Franshitco?

Pretty unwise, but about the city leaders speed there.

 

[RamFan503]

Now… they will be spending waaay more to fix it.

Wow, $4M is pocket change compared to the end game on what this mess will likely cost to clean up.

As with most things, it is far more costly to fix a mistake than to do it right in the first place. Add to that the obviously inevitable lawsuits on a project of this size and I wouldn't doubt if the "fix" costs more than the original project. Dumbasses.

 

[CGI_Ram]

As with most things, it is far more costly to fix a mistake than to do it right in the first place. Add to that the obviously inevitable lawsuits on a project of this size and I wouldn't doubt if the "fix" costs more than the original project. Dumbasses.

$100 million to fix!

The $100M project to fix SF's leaning Millennium Tower stopped as high-rise keeps tilting and sinking

A construction project to halt the sinking of the Millennium Tower in San Francisco has stopped as it sinks another inch and tilts five more inches.

www.usatoday.com

 

[RamFan503]

$100 million to fix!

Gotta START somewhere.

 

[Neil039]

This is insane. One quake a way from a huge catastrophe IMO

 

[CGI_Ram]

This was a fascinating series. 5 parts in total. Well done by this guy.

It is a great series if you are into engineering mixed with potential disaster type stories.

The tower continues to lean… and it hasn’t stopped moving yet.

PART ONE

View: https://youtu.be/OOWn-HMd5Co


PART TWO

View: https://youtu.be/gIxhpP7hQu4


PART THREE

View: https://youtu.be/jsl37A0KMj8


PART FOUR

View: https://youtu.be/9J3OZyX_qM4


PART FIVE

View: https://youtu.be/Xezg8PxVSYA


LATEST UPDATE

View: https://youtu.be/5DOJNeLEPBA

 

[Angry Ram]

All i can think of is how many CEOs and managers decided to cut corners to save up front costs.

Side note...I'm sooooo glad I didn't get into engineering. The amount of stress to begin with plus dealing with this shit. Nope nope nope. Give me environmental all day every day.

 

[FaulkSF]

This was a fascinating series. 5 parts in total. Well done by this guy.

It is a great series if you are into engineering mixed with potential disaster type stories.

The tower continues to lean… and it hasn’t stopped moving yet.

PART ONE

View: https://youtu.be/OOWn-HMd5Co


PART TWO

View: https://youtu.be/gIxhpP7hQu4


PART THREE

View: https://youtu.be/jsl37A0KMj8


PART FOUR

View: https://youtu.be/9J3OZyX_qM4


PART FIVE

View: https://youtu.be/Xezg8PxVSYA


LATEST UPDATE

View: https://youtu.be/5DOJNeLEPBA

I haven't watched the videos yet, but another consideration in Nor Cal is the constant shifting of soil. We go through two-three years of drought. Then boom, a wetter season than average.

While I do not live in a structure like the millennial towers, I've still had my share of issues from foundational shifts caused by inconsistent weather.

 

[snackdaddy]