57 story building in SF tilting- this will not end well

MAGA MAN

Let's go Brandon!
The 58-story building has gained notoriety in recent weeks as the "leaning tower of San Francisco." But it's not just leaning. It's sinking, too. And engineers hired to assess the problem say it shows no immediate sign of stopping.

Completed seven years ago, the tower so far has sunk 16 inches into the soft soil and landfill of San Francisco's crowded financial district. But it's not sinking evenly, which has created a 2-inch tilt at the base - and a roughly 6-inch lean at the top.

Eerily reminiscent of other historic structural disasters, the engineers and developers see it slowly happening and are in complete denial:
In a February 2009 letter, a chief buildings inspector, Raymond Lui, wrote to the tower's engineering firm to express concerns about "larger than expected settlements." He asked what was being done to stop the sinking and if the building's structural safety could be affected.

DeSimone Consulting Engineers replied that the building had already unexpectedly settled 8.3 inches. But the engineering firm concluded, "It is our professional opinion that the structures are safe."

Millennium Partners maintains its design is safe and says many San Francisco high-rises have similar foundations.

"We did this building the right way," Chris Jeffries, a founding partner at Millennium Partners, told a news conference. "The building is 100 percent safe."

hosted.ap.org/dynamic/stories/U/US_LEANING_TOWER_OF_SAN_FRANCISCO?SITE=AP&SECTION=HOME&TEMPLATE=DEFAULT&CTIME=2016-10-24-00-08-11
 
Most expensive residential building in the City. Got some big names like Joe Montana and Hunter Pence that live in it. You have smart and well heeled people on all sides here. This is going to be a long and expensive workout.
 
Thingy will blame Bush....
Evince will say it was built by racists...
Others will blame climate change...
some will say its fracking....
and on and on it will go.
 
Leaning more on top than at the base. As an engineer it's obvious to me what the structure is doing- reacting as if hit by a constant wind. What do they think will happen when the design wind load occurs?
 
Leaning more on top than at the base. As an engineer it's obvious to me what the structure is doing- reacting as if hit by a constant wind. What do they think will happen when the design wind load occurs?

???.....actually, as a non-engineer its pretty obvious to me why its leaning more at the top than at the base also......the farther the arc gets from the base, the more exaggerated its going to become......
 
I am not an engineer either. What I know from following this case is they didn't build into the bedrock, but other buildings haven't done that either and not had this problem. The building developers blame the development going up next door for messing with their building. My buddy works for a REIT which owns a building a couple of blocks away and prior to this he was negotiating a tie back agreement with a group building adjacent to his building. After hearing this story it took on a whole new meaning.
 
What's the appropriate remedy?

- The main construction phase is over.

- The building is already occupied, generating revenue.

Shall they demolish it? Start over?

If not that, what?
 
Thingy will blame Bush....
Evince will say it was built by racists...
Others will blame climate change...
some will say its fracking....
and on and on it will go.


While Partisan Righties will claim it's all Obama's and/or Hillary's fault.
 
#11

So the remedy for extremism from the right is extremism from the left?
"Sunlight is the best disinfectant". Louis D. Brandeis
If they're wrong, why not quote the error, and then expose it?
 
"they don't accept facts any more"
a) They used to?

b) We don't need their validation.

I understand. Sometimes it seems like a discreet conversation between two.

But it may often not be.

There are other posting members that will read and decide.

AND

There may be more non-posting members ("lurkers") than you may suspect.
They are (we are) your audience as well.

Tell the truth!
You needn't squabble. You needn't bicker.
But why not correct errors of fact?

We're two weeks from a U.S. presidential election. The leading candidates include one of the most qualified, and perhaps the least qualified candidates ever to seek the office with major party endorsement.

Why would you consider withholding correction on errors of fact a legitimate option?
Would you want one of your countrymen to do that to you?

"Truthmatters" you know.

TELL IT !! Don't be a hypocrite, preaching one thing, but doing another.
 
Why weren't the piles driven down to bedrock as they should be on any high-rise structure?
Corporate greed.
Follow the money.
 
Another 7 inches might not have done it.

How much deeper would they have had to go to reach bedrock?
A foot?
A mile?

Bedrock is OBVIOUSLY the superior option.
How much would it have added to the cost per square foot?

1%?
10%?
100%?
1,000%?

If ever I learned ANYTHING in my decades in high tech industry:

Absolutely EVERYthing in engineering is a compromise!

Absolutely EVERYTHING!

I defy ANYone to cite a single refutory example.
 
Another 7 inches might not have done it.

How much deeper would they have had to go to reach bedrock?
A foot?
A mile?

Bedrock is OBVIOUSLY the superior option.
How much would it have added to the cost per square foot?

1%?
10%?
100%?
1,000%?

If ever I learned ANYTHING in my decades in high tech industry:

Absolutely EVERYthing in engineering is a compromise!

Absolutely EVERYTHING!

I defy ANYone to cite a single refutory example.

Who are you talking to?
 
The Transbay Joint Powers Authority, which is building the $4.5 billion Transbay Transit Center next door to the Millennium, blames the building’s structural shortcomings on the developer not using what are called “end bearing piles,” which would have reached down 200 feet into the bedrock. Instead, it rests on more than 900 “friction piles” between 60 and 91 feet in length driven into the dense mud that lies beneath fill dumped into the bay more than a century ago...
But San Francisco’s other tall buildings that use friction piles have steel frames, rather than concrete, and therefore are far lighter than the Millennium Tower, according to Transbay Joint Powers Authority.

On Friday the transbay authority released a report by the engineering firm ARUP, showing that the Millennium Tower is four to five times heavier than any other building in the area with a similar foundation, including 100 First St., 199 Fremont St. and 555 Mission St.

Building weights are measured in kips — 1,000 pounds — per square foot of pressure on the soil below. The tower at 555 Mission, for example, is 487 feet tall compared with 645 for the Millennium, but it exerts 2.4 kips per square foot while the Millennium exerts 11.4 kips.

“While a foundation with shallow piles may have been appropriate for other, much lighter high-rises, it was clearly not appropriate for the Millennium Tower,” the TJPA report stated.

The issue of whether the Transbay district’s squishy fill could support a heavy residential building came up in 2004 when the city fought developer Jack Myers’ plan to build a 53-story tower at 80 Natoma, which also abuts the Transbay Transit Center.

Myers wanted to use a combination of mat slab and friction piles, which he said was more than adequate to support the building. But Maria Ayerdi-Kaplan, who was then the director of the TJPA, objected to the project because, she said, the foundation was inadequate and would have interfered with the underground train route coming into the transit center. At the time, Ayerdi-Kaplan said she pushed the developer to go to bedrock, but he refused.
http://www.sfchronicle.com/bayarea/article/Sinking-Millennium-Tower-s-developer-built-9278364.php



91 instead of 200 Feet.That's the difference in pile depth to bedrock. This building is five times heavier than other structures that have successfully used friction piles.
The contractor used laws written for steel frame high-rises and applied them to a heavier reinforced concrete structure.
He pocketed the savings that came from not going to bedrock with the supporting piles.
Follow the money.
He is probably a republican.
 
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#18

Thanks.

I did not know that.

The New York State Thruway's Tappan Zee bridge is being replaced.
It crosses the mighty Hudson River where the river is ~3.5 miles wide.

The replacement bridge reportedly uses friction piles in the muddy Hudson's bed.

We'll see how that works out.
 
#18

Thanks.

I did not know that.

The New York State Thruway's Tappan Zee bridge is being replaced.
It crosses the mighty Hudson River where the river is ~3.5 miles wide.

The replacement bridge reportedly uses friction piles in the muddy Hudson's bed.

We'll see how that works out.

Friction piles are a cheap ticking time bomb. A budget alternative designed for lightweight structures making them a temporary, constantly sinking structure.
Bedrock pile driving is expensive unless the bedrock is close to the surface like under Manhattan.
It is also the only truly reliable way to build high rise structures.
The skyline of Manhattan's tall buildings is an echo of the bedrocks profile. The tallest buildings were built in midtown where the bedrock is only a few meters below grade .

Building a heavy, reinforced concrete structure 57 stories tall using friction piles into mud was an irresponsible thing to do.
We now see why.

https://blog.epa.gov/blog/2015/07/the-manhattan-skyline-why-are-there-no-tall-skyscrapers-between-midtown-and-downtown/
 
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