SF luxury tower has sunk 16 inches, and tilted 2

[LadyStanley]

http://sanfrancisco.cbslocal.com/20...y-high-rise-millennium-tower-is-sinking-fast/

According to KCBS and Chronicle Insider Phil Matier, an engineering report says that the 58-story, $350 million luxury high rise has sunk by 16 inches since its completion in 2009. It’s also tilted by two inches to the northwest.
...
Who is to blame for the problem depends on who you ask.

Millennium Tower officials say the sinking was triggered by excavation work for the nearby Transbay Terminal. But Transbay officials point out that the tower had already sunk by ten inches before the Transbay dig began. They blame the problems on the way the high-rise was built.

“To cut costs, Millennium did not drill piles to bedrock,†said the transit authority in a statement. Had it done so, “the tower would not be tilting today.â€

In fact, the Millennium Tower sits on an area of mud-fill. It is not steel-framed, and instead relies on shear walls, columns and beams. The building is anchored over a thick concrete slab and its pilings extend about 80 feet into dense sand, not into the bedrock which lies about 200 feet below street level.

I smell a lawsuit against the builders.

Click to read more...

 

[Lost Horizons]

if it's sinking and tilting now just wait until an earthquake hits the area. Watch out below!

 

[shortshorts]

Geotechnical engineer here.

I highly doubt that the shorter piles are causing this issue. For 16 inches of differential settlement to occur, the project geotechnical engineers must be grossly negligent. I refuse to believe that they didn't capture that in their design.

"Aware that the Millennium Tower foundation failed to reach bedrock and was therefore inadequate to support the Tower"

That on its own is a stupid statement. They essentially said the geotechnical engineers were unable to do basic load bearing foundation design.

 

[Sharpshooter]

Geotechnical engineer here.

I highly doubt that the shorter piles are causing this issue. For 16 inches of differential settlement to occur, the project geotechnical engineers must be grossly negligent. I refuse to believe that they didn't capture that in their design.

"Aware that the Millennium Tower foundation failed to reach bedrock and was therefore inadequate to support the Tower"

That on its own is a stupid statement. They essentially said the geotechnical engineers were unable to do basic load bearing foundation design.

Maybe they didn't. Why are you defending them so vociferously?

It's possible that they were shady or inept, or both. You shouldn't refuse to believe anything until all the facts are in, and i'm sure the facts should come out through a thorough investigation.

 

[Oilslick941611]

if it's sinking and tilting now just wait until an earthquake hits the area. Watch out below!

its okay, its san fran, its not an active area for earthquakes.

 

[Hurt]

Geotechnical engineer here.

I highly doubt that the shorter piles are causing this issue. For 16 inches of differential settlement to occur, the project geotechnical engineers must be grossly negligent. I refuse to believe that they didn't capture that in their design.

"Aware that the Millennium Tower foundation failed to reach bedrock and was therefore inadequate to support the Tower"

That on its own is a stupid statement. They essentially said the geotechnical engineers were unable to do basic load bearing foundation design.

Ineptitude is a universal issue.

With that said, in your opinion, how can this be corrected (if at all)?

 

[ArGarBarGar]

Geotechnical engineer here.

I highly doubt that the shorter piles are causing this issue. For 16 inches of differential settlement to occur, the project geotechnical engineers must be grossly negligent. I refuse to believe that they didn't capture that in their design.

"Aware that the Millennium Tower foundation failed to reach bedrock and was therefore inadequate to support the Tower"

That on its own is a stupid statement. They essentially said the geotechnical engineers were unable to do basic load bearing foundation design.

Are you saying certain geotechnical engineers don't sometimes suck at their job? It happens all the time, in every field.

 

[LadyStanley]

http://sanfrancisco.cbslocal.com/2016/08/08/millennium-tower-residents-structural-problems-claims/

Residents file suit. So I'm assuming that a lot more news/specs will be coming out should the suit go forward.

 

[shortshorts]

Maybe they didn't. Why are you defending them so vociferously?

It's possible that they were shady or inept, or both. You shouldn't refuse to believe anything until all the facts are in, and i'm sure the facts should come out through a thorough investigation.

Design engineer's are required to do professional reviews of other's work. It is possible that the original designer is a moron and that the reviewer was grossly negligent. However, I don't believe it was for the simple reason stated in the article. A bearing capacity calculation is basic undergraduate material. If anything, they were negligent about another factor. I.E. not doing enough site characterization (reducing project costs)

Ineptitude is a universal issue.

With that said, in your opinion, how can this be corrected (if at all)?

Money, lots of god damn money. I.E jet grouting case history on how they stopped leaning tower of Pisa.

Are you saying certain geotechnical engineers don't sometimes suck at their job? It happens all the time, in every field.

For a failure like this to happen. It requires multiple engineers to not only suck at their job, but be grossly negligent. As stated above, all design phases must be reviewed several times by another engineer.

If it is indeed true as the article states... people are going to jail and losing their licenses.

 

[Bluelines]

Geotechnical engineer here.

I highly doubt that the shorter piles are causing this issue. For 16 inches of differential settlement to occur, the project geotechnical engineers must be grossly negligent. I refuse to believe that they didn't capture that in their design.

"Aware that the Millennium Tower foundation failed to reach bedrock and was therefore inadequate to support the Tower"

That on its own is a stupid statement. They essentially said the geotechnical engineers were unable to do basic load bearing foundation design.

Couldn't be as simple as greedy developers railroading the engineers to do something that knew was wrong?

 

[BigMac1212]

The next Leaning Tower of Pisa?

 

[LadyStanley]

http://www.sfgate.com/bayarea/article/Agency-says-it-will-keep-pumping-water-near-9238395.php

Developers blaming "dewatering" next to and underneath tower as the cause of the tilt.


So should that be summarized as the "plot thickens" or the "dewatering thickens"?

 

[shortshorts]

Couldn't be as simple as greedy developers railroading the engineers to do something that knew was wrong?

The engineers are consultants. They provide a "recommended" (suitable) design and its up to the developers to accept it. There is very little pull a developer would have on the consultant unless they were already big time business partners (i.e. they'll work again in the future).

Usually what happens in geotechnical design is developers cheap out on site investigation. In this case, however, if there were a lack of data the engineers would design more conservatively to account for uncertainties in the data. In other words, they would've been for the conservative design of piles going into bed rock... not shorter piles.

It is either the design crew was grossly negligent (possible but I'm veering against that possibility...) or there were outside conditions that weren't accounted for...

Such as...

http://www.sfgate.com/bayarea/article/Agency-says-it-will-keep-pumping-water-near-9238395.php

Developers blaming "dewatering" next to and underneath tower as the cause of the tilt.

So should that be summarized as the "plot thickens" or the "dewatering thickens"?

Differential settlement is definitely a possibility due to off-site pumping. A cone of depression around the pumping location removes water from the pores of soil and allows for the settlement of soil. The other site cites that a shoring wall separates the two properties and is therefore not their fault... However, more information needs to be revealed there.

Was it a typical flexible shoring wall with shotcrete placed over it? In that case, water can definitely travel through it. Or was it a hydraulically sealed wall?

I'll be interested to see what comes out of this. I'm sure there will be some partial blame on both parties...

It really could have come down to a combination of a very unconservative (but still appropriate design) and an outside system forcing.

 

[LadyStanley]

http://sanfrancisco.cbslocal.com/20...er-sinking-mayor-ed-lee-high-rise-task-force/

Mayor wants task force to review high rise building codes.

 

[Satan]

The city first voiced its concerns a decade ago, in 2006, worried the Millennium Tower foundation design wouldn’t support the weight of the concrete tower. But the city allowed construction to continue.

Three years later, in 2009, the Department of Building Inspection sent a letter to the builder explicitly asking about the sinking foundation and what was being done about it. Only the man who sent that letter can’t say why he started asking those questions.

“I do not recall where exactly I got that information,” said Raymond Lui of the Department of Building Inspection.

This has been quite funny to follow and it sounds like negligence all around.

 

[shortshorts]

This has been quite funny to follow and it sounds like negligence all around.

That's quite a quote, lol.

I'd assume the City was concerned it didn't go into bedrock (similar to other buildings in the area) and the engineers showed them their design which showed it would be fine.

 

[LadyStanley]

http://sanfrancisco.cbslocal.com/20...alled-to-measure-sinking-of-millennium-tower/

Now the HOA is installing sensors to measure "settlement"

 

[MAHJ71]

I don't know whats more interesting - the situation itself or the fact we have a geo engineer that can give us the play by play.. LOL

 

[Satan]

That's quite a quote, lol.

I'd assume the City was concerned it didn't go into bedrock (similar to other buildings in the area) and the engineers showed them their design which showed it would be fine.

built on a former landfill- you'd think they'd be more conservative but $ talks???

 

[LadyStanley]

http://www.sfgate.com/bayarea/article/Sinking-Millennium-Tower-under-stress-in-14-9476271.php

Engineers reporting that building was "under stress" in 2014.

Private structural engineers who examined the sinking Millennium Tower in 2014 concluded that “some limited elements” of the building were under “significant stresses” as a result of the settlement and were “more susceptible to damage from an earthquake,” according to newly released public documents. The assessment, included in a July 25 staff memo on the building, concluded that the tower could still survive a quake and that residents’ safety had not been “significantly affected.”

 

[LadyStanley]

http://sanfrancisco.cbslocal.com/20...ng-millennium-tower-can-withstand-earthquake/

“We conclude that the settlements experienced by the 301 Mission tower have not compromised the building’s ability to resist strong earthquakes and have not had a significant impact on the building’s safety,” the report states.

Well, there's one expert (company) opinion.

 

[LadyStanley]

http://sanfrancisco.cbslocal.com/2016/10/28/peskin-supervisors-meeting-millennium-tower/

City supervisors call in building inspectors and call into question their lack of follow through (i.e., being proactive on issues rather than waiting for complaints).


http://www.sfgate.com/bayarea/article/Violations-found-in-repairs-to-sinking-tilting-10421476.php

Inspectors now report violations.

 

[chicagoskycam]

Satellite data shows tower continues to sink at double the expected rate.

http://www.foxnews.com/us/2016/11/28/leaning-san-francisco-tower-seen-sinking-from-space.html

The satellite data shows the Millennium Tower sunk 40 to 45 millimeters — or 1.6 to 1.8 inches — over a recent one-year period and almost double that amount — 2.6 to 2.9 inches — over its 17-month observation period, said Petar Marinkovic, founder and chief scientist of PPO Labs which analyzed the satellite's radar imagery for the ESA along with Norway-based research institute Norut.

"What can be concluded from our data, is that the Millennium Tower is sinking at a steady rate," Marinkovic said in a telephone interview Monday from The Hague, Netherlands.

 

[Hurt]

So what are next steps for this Tower? Tear down? That would cost multi millions. Fix the foundation? Probably cost a ton as well.

 

[LadyStanley]

So what are next steps for this Tower? Tear down? That would cost multi millions. Fix the foundation? Probably cost a ton as well.

Lawsuit to find fault so that remedy can be paid for by somebody(ies).