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San Francisco Luxury High Rise Sinking

Huntn

Huntn

macrumors Penryn
Original poster
May 5, 2008
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The Misty Mountains
Holy Crap!! Word has it that they did not run the foundation down to the bedrock. What an embarrassment. Is this a crisis?

SF Landmark, Luxury High-Rise Millennium Tower Is Sinking Fast

Millennium-Tower-SF.jpg

August 1, 2016 9:10 AM
SAN FRANCISCO (KCBS) — The Millennium Tower, one of the city’s most prestigious addresses, is sinking fast.

The luxury high-rise is home to celebrities like Joe Montana and Hunter Pence. Condominiums in the 58-story building have price tags as high as $10 million.

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.
 
iLog.Genius said:
Clearly not an expert in structural engineering/architecture but when something like this happens, is there any way to remedy the fault?
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I'm not either but maybe it will stop when it hits bedrock. That said, by then it might be better known as the Leaning Tower of Frisco.



Mike
 
iLog.Genius said:
Clearly not an expert in structural engineering/architecture but when something like this happens, is there any way to remedy the fault?
Click to expand...

My guess as a non-engineer is that it might be correctable if they spend a boat load of money on driving down support to the bedrock if there is a technical capability. For all the work that was done on the Leaning Tower of Pisa, it is teeny in comparison, maybe 12 stories with a small foot print.
 
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Huntn said:
Holy Crap!! Word has it that they did not run the foundation down to the bedrock. What an embarrassment. Is this a crisis?

SF Landmark, Luxury High-Rise Millennium Tower Is Sinking Fast

Millennium-Tower-SF.jpg

August 1, 2016 9:10 AM
SAN FRANCISCO (KCBS) — The Millennium Tower, one of the city’s most prestigious addresses, is sinking fast.

The luxury high-rise is home to celebrities like Joe Montana and Hunter Pence. Condominiums in the 58-story building have price tags as high as $10 million.

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.
Click to expand...
Apparently the builders they used came in cheapest. Although they had previously worked in Pizza.
image.jpg


In all seriousness I'd have some serious safety concerns.
 
Huntn said:
I think it's the same deal for Pisa, it was built on dirt, not on a solid foundation. I imagine this is a disaster for the buildings owners and financiers.
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I should imagine it worked out well for Pisa in the long run!
I have actually been up that tower. It feels weird.
It's built on sand basically. It was under pinned by concrete some years ago to stop it moving any further.
 
“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.”
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Ouch. Cutting corners to 'save money' comes back to bite you in the ***. Who knew!?
 
Boy am I glad I'm not that structural engineer. Or their insurer. Although it could be the geotechnical engineer's mess-up too, if the structural engineer was told the soil friction was higher than it is. Guess I'll know if any big players around here go belly-up over this.

Most things are fixable, given enough money. But the logistics of this seem... daunting. I'd want to go through the existing foundation to add deep piles, but how you get a drill rig into a basement is just one question of many I'd have.

Yeesh...
 
Thank god for insurance.

Boston doesn't have a lot of bedrock, making building skyscrapers difficult, which is why we have so few. Back Bay buildings are beginning to sink and tilt considering not too long ago the area was a swamp that was filled in.
 
iLog.Genius said:
Clearly not an expert in structural engineering/architecture but when something like this happens, is there any way to remedy the fault?
Click to expand...

I'm sure there are many faults in the vicinity.

I just looked at the Google Street View of the tower from June 2016. I'd expect some external indication after 16" of sinking, but I didn't see anything. The article says "so far the only signs have been cracks in the garage and an ongoing problem with the sidewalk." It also says that the building is in an area of mud fill and that the pilings go down into "dense sand," not exactly comforting during the next earthquake.
 
Roller said:
I'm sure there are many faults in the vicinity.

I just looked at the Google Street View of the tower from June 2016. I'd expect some external indication after 16" of sinking, but I didn't see anything. The article says "so far the only signs have been cracks in the garage and an ongoing problem with the sidewalk." It also says that the building is in an area of mud fill and that the pilings go down into "dense sand," not exactly comforting during the next earthquake.
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It's likely got a mat foundation, where the entire footprint of the building is a solid mass of rebar and concrete, acting to diffuse the point loads of the columns above and the piles below. Settlement issues tend towards the entire thing moving together, so less racking (visible cracking), more sinking and leaning.

The real problems right now I bet revolve around access and utilities. I can't imagine the driveways still function as designed if there's 16" of settlement. Required accessible routes are in immediate jeopardy. Draining water away from the building exterior gets harder. At some point it will surpass the capacity of the water, gas storm drain, and sewer lines to flex. The fire department is probably keeping a close eye on the situation...
 
mactastic said:
It's likely got a mat foundation, where the entire footprint of the building is a solid mass of rebar and concrete, acting to diffuse the point loads of the columns above and the piles below. Settlement issues tend towards the entire thing moving together, so less racking (visible cracking), more sinking and leaning.

The real problems right now I bet revolve around access and utilities. I can't imagine the driveways still function as designed if there's 16" of settlement. Required accessible routes are in immediate jeopardy. Draining water away from the building exterior gets harder. At some point it will surpass the capacity of the water, gas storm drain, and sewer lines to flex. The fire department is probably keeping a close eye on the situation...
Click to expand...

If the entire building is sinking as a unit, wouldn't there be a positional change with respect to surrounding structures (sidewalks, driveways, and so on)? 16" seems like a lot to me, even if it occurred gradually, so I'd imagine there would be more visible evidence at street level.
 
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Ok, so its sinking, but what wasn't mentioned is that SF is in an earthquake zone. With it slowing tilting and sinking, I would think its may be even more dangerous if an earthquake struck
 
tobefirst said:
I bet owners are dreading that special assessment. Yikes. (;
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Couple that with the falling values, i.e., who wants to buy a condo in a building that is sinking, and you have some very nervous and unhappy owners.
 
Roller said:
If the entire building is sinking as a unit, wouldn't there be a positional change with respect to surrounding structures (sidewalks, driveways, and so on)? 16" seems like a lot to me, even if it occurred gradually, so I'd imagine there would be more visible evidence at street level.
Click to expand...
Yes. Driveways, walkways, utility lines. 16" is a huge amount of settlement.
 
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