20 ms·

Millennium Tower is tilting, sinking

268 points by lelf 10y ago

Nuffinatall 10y ago
Pretty sure they need to safely dismantle this building and try again. In non-earthquake prone areas, it might make sense to jack it up and what not, but not in SF.
- dpark 10y ago
  There is no scenario in which a 350 million dollar skyscraper deemed "not a safety issue for residents" will be torn down so they can "try again". They'll find a way to stabilize it and that will be that. No one is going to tear down nearly half a billion dollars worth of skyscraper if there's any chance of salvaging it.
  - nostromo 10y ago
    It's not without precedent. In Seattle a cost-cutting method was used to build a 25-story downtown apartment building in 2001. In 2010 it was found to be flawed and unfixable, and so it was dismantled. And now there's a new building being built on the site. http://www.seattletimes.com/seattle-news/9-year-old-belltown-high-rise-too-flawed-to-fix/ http://www.seattletimes.com/seattle-news/9-year-old-belltown...
    - dpark 10y ago
      Key there is it was deemed unfixable. $350 MM can do a lot of fixing. Edit: To be clear, I'm not denying the entire possibility. It's just extremely unlikely, especially given that the tower is currently deemed safe.
      - spikels 10y ago
        Plus if it turns out to have been caused by the Trans Bay Terminal, they have very deep pockets (they supposedly spent $58 million on a buttress to protect the Millineum Tower). As does the developer, Millennium Partners and the engineering from firm's insurance companies. This will get fixed. There will just have to be a big fight to see who has to pay.
pnevares 10y ago
A fair warning that sinking doesn't just happen to towers: http://science.time.com/2012/05/21/soaring-to-sinking-how-building-up-is-bringing-shanghai-down/ http://science.time.com/2012/05/21/soaring-to-sinking-how-bu...
cheeze 10y ago
What is the risk? Does this make the building more dangerous because it's in an earthquake-prone area? Obviously this doesn't sound good, but the article mentions that there is no threat to safety of occupants. Is it merely aesthetic?
- simulate 10y ago
  This other article discusses how uneven sinking of the tower causes cracks and elevator issues: http://www.sfchronicle.com/bayarea/article/SF-s-landmark-tower-for-rich-and-famous-is-8896563.php http://www.sfchronicle.com/bayarea/article/SF-s-landmark-tow... > And while Stanford’s Deierlein doesn’t consider the sink or tilt a safety issue, he did say, “I would be concerned for my investment.” That’s because a shifting building can cause walls to crack, elevators to malfunction and all manner of other annoyances.
- erdevs 10y ago
  How much stock should one put in that declaration of safety? It is from an "independent" analysis... but who paid the analysts? Or, suppose absolute freedom from bias... how many times have expert opinions of safety been wrong in the face of mother nature. Picture Fukushima. The risks in a tilting building are many. From a market value standpoint, homeowner value has already been destroyed simply by perception. If remediation is necessary here, homeowner fees could dramatically increase. Tilting buildings often see cracks in walls, malfunctioning elevators and other ills which also lower value. There will be lawsuits here-- you can see all sides rattling sabers with legalistic language and positioning already just from these articles -- and those will carry costs as well. Taxpayers may well be pulled into the fray and suffer as well in these situations. From a pure safety standpoint, experience dictates that we should discount expert declarations of safety in many such matters. Residents of the tower and the towers' neighbors may do well to heed caution. At the end of the day, it is hubris to expect to predict with any high degree of confidence what might happen here. After all, none of the experts from any side involved foresaw even the current predicament, where no grand act of nature is even involved. The building simply stands there, yet already reacts in unpredicted ways. How likely are the experts then to foresee predicaments in even more complex situations?
sharpercoder 10y ago
I wonder what effect a medium to heavy earthquake would have on this building's foundation.
- erdevs 10y ago
  Probably not good. According to this and other articles, the building's concrete slab foundation sits roughly 80 ft below street level upon sand, while bedrock lies 200 ft down. That means there is 120 ft of sand, possibly susceptible to liquefaction, between the buildings foundation and solid bedrock. That sounds bad enough. But now imagine the building is tipping over slightly. The already potentially worrisome problem compounds dramatically.
  - clock_tower 10y ago
    How much would it have cost to dig down to bedrock, and pour a concrete foundation from the bedrock up to surface level? Between the amount of sand to be moved and the amount of concrete to be poured, it sounds like an enormous fortune; I guess that the relevant questions are whether the market could bear it and whether it would be cheaper than the rapidly-developing lawsuits. It may be that the building didn't make economic sense in the first place, if it couldn't be built both safely and profitably -- which has unpleasant implications for the SF housing crunch...
    - WalterBright 10y ago
      The real problem with digging down to bedrock is destablizing the building. Though there may be enough redundancy in the pilings to do it one at a time.
      - vonmoltke 10y ago
        I think the question was why the builders didn't do it in the first place.
        10y ago
WalterBright 10y ago
My house is on a steep hill, and Seattle has a reputation for hills sliding away under heavy rain. Before building it, I hired 3 separate geologists to evaluate the site. After digging holes, they said the site was sitting on "glacial till", which is clay that was compacted by about a mile of ice, and said there was nothing to worry about. Paying them was worth it for the peace of mind. (Turns out the till was so hard it could not be dug with hand tools.) I did have a scare because a spring appeared on the edge of the property, as underground water is indicative of slide risk. Fortunately, it turned out to be a leak in the water main! I still made sure the hard surfaces all drained into the storm drain, so that the hill wouldn't become saturated with water. I can't conceive of building a 58 story building on sand in an earthquake zone. Reminds me of that Monty Python quote: "When I first came here, this was all swamp. Everyone said I was daft to build a castle on a swamp, but I built in all the same, just to show them. It sank into the swamp. So I built a second one. That sank into the swamp. So I built a third. That burned down, fell over, then sank into the swamp. But the fourth one stayed up. And that's what you're going to get, Lad, the strongest castle in all of England."
- clock_tower 10y ago
  Building a large edifice on sand? Put that starkly, I could swear that I heard a story about it once. No idea where, though. ;)
  - PhasmaFelis 10y ago
    I recall a Sunday School song to that effect, with hand gestures. "Theeeeeeeeee foolish man built his house upon the sand, the foolish man built his house upon the sand..."
- WalterBright 10y ago
  One of the geologists told me a simple way to judge the slide risk. Look at the tree trunks. If tree trunks are leaning, or are curved, that indicates the ground under them is shifting.
  - 10y ago
qq66 10y ago
16 inches over 8 years is absolutely insane. That's the Usain Bolt of a sinking building.
- buckbova 10y ago
  Reminded me of the Mandalay Bay incident some years ago. Apparently they tried to cheap out and use a previous soils report from an adjacent area. > The tower was sinking ½ to ¾ inches a week http://traveltips.usatoday.com/mandalay-bay-history-10712.html http://traveltips.usatoday.com/mandalay-bay-history-10712.ht...
- torgoguys 10y ago
  And the article mentions it was 10 inches in only (it's first) 2 years after completion!
  - matthewowen 10y ago
    Good news, the sinking is slowing! :/
    - PhasmaFelis 10y ago
      If the pilings go down 80 feet, and bedrock is at 200 feet, then worst case you'll still have 46 usable stories!
philip1209 10y ago
"To cut costs, Millennium did not drill piles to bedrock." What are the implications for earthquake safety?
- helmett 10y ago
  I'm sure the engineers ran the calculations and deemed it 'safe enough'
  - jonathankoren 10y ago
    Or some investor did.
    - Gracana 10y ago
      Investors will always want things cheaper, and they don't understand engineering. The responsibility of ensuring that the design is safe falls on the engineer who stamped the drawing. Situations like this are covered in engineering ethics classes, which most civil engineers in the US would have taken.
      - r_smart 10y ago
        Plus, depending on the state, a Professional Engineer (a certification earned) has to sign off on this stuff and is liable in the event of something catastrophic happening, like the building falling over.
- mcguire 10y ago
  Not a geologist, but I suspect that'll depend on how liquid the 120' of sand between the piles and the bedrock gets.
- capkutay 10y ago
  Because Millennium is on reclaimed land, they cannot determine whether or not they have drilled into bedrock. They drill into what's called the 'point of refusal'; a point where they can no longer drill deeper. Whether this is bedrock or even stable soil is somewhat vague.
helmett 10y ago
...2 inches for such a tall building is such tiny angle If it sinks does this mean the first floor is slightly below the street level ..it probably means that the areas around the door and where the concete meets the street are cracked
- carleverett 10y ago
  I was wondering the same thing, but Google street view (taken in 2014) doesn't show any evidence of such a big dip. How is that possible?? The only thing I can think of is that it's more of a "sag," where the middle has sunk 18" but the edges haven't moved much, but I'm not really satisfied with that theory. https://www.google.com/maps/place/Millennium+Tower+San+Francisco/@37.7901875,-122.3962408,3a,90y,237.99h,64.97t/data=!3m8!1e1!3m6!1s-35rB20DzRME%2FU7BvmBlYzUI%2FAAAAAAAAKgs%2FidvFTvbnBG4BG0iCULQUc1scg2DlGAkaw!2e4!3e11!6s%2F%2Flh5.googleusercontent.com%2F-35rB20DzRME%2FU7BvmBlYzUI%2FAAAAAAAAKgs%2FidvFTvbnBG4BG0iCULQUc1scg2DlGAkaw%2Fw203-h101-n-k-no%2F!7i11884!8i5942!4m5!3m4!1s0x0:0x9fe15ebd4a8300d8!8m2!3d37.7905058!4d-122.3961611!6m1!1e1 https://www.google.com/maps/place/Millennium+Tower+San+Franc...
  - dpark 10y ago
    It's extremely unlikely that the building is sinking and the surrounding area is stable. More likely the building is pulling the entire area down, so it's probably hard to detect as a pedestrian.
    - Naritai 10y ago
      A commenter upstream reports seeing the sidewalk being repaired multiple times throughout the last 10 years as well.
- tedunangst 10y ago
  Wouldn't the width be a more appropriate measure than height?
  - Ankaios 10y ago
djsumdog 10y ago
The article doesn't talk about the how this practically affects the entrances to the building. Do the doors have to be adjusted for such a drastic sinkage, or are buildings somehow designed so this isn't noticeable to the public?
- VonGuard 10y ago
  Seems to imply they had to do something to the entrances, but not what. Maybe there are little ramps added every year? I'm gonna go look now.
  - jonah 10y ago
    Please take some pictures and share them with us. Another article I read said they have needed to make adjustments to the first floor interface but didn't say what they were.
    - deleted 10y ago
      [deleted]
- zubat 10y ago
  I don't know what skyscrapers do but throughout SF one can find smaller houses that have subsided. They dealt with the problem by adjusting the sidewalk and adding ramps, some of which are absurdly steep now.
  - duaneb 10y ago
    That explains so much.
- pmontra 10y ago
  The sidewalk around the building is sinking with it. See this video https://youtu.be/WMutQBXj5X4 https://youtu.be/WMutQBXj5X4
Animats 10y ago
From the article: "To cut costs, Millennium did not drill piles to bedrock." I'm amazed that a building of that height would be built on a slab with friction piles in the mudflat fill zone of the SF bay. How did they get a building permit for that? 16 inches of sinkage in 8 years is huge. Building sinkage isn't all that unusual, but not for skyscrapers. There was a time when skyscrapers were only built on competent rock, like NYC's. Now they're being built on much more iffy soils. Singapore and some other coastal Asian cities are doing a lot of this. SF used to be smaller. The outer half mile or so on the bay side is fill. There are buried shipwrecks all through that area.[1] [1] https://medium.com/the-secret-history-of-america/from-starboard-to-shot-glass-941b8a863c69#.8r2p8rewz https://medium.com/the-secret-history-of-america/from-starbo...
- Finnucane 10y ago
  Most of our big coastal cities are like that. Boston is about twice as big as it was in colonial times; all of the Back Bay is landfill. A lot of Cambridge is landfill. And yes, most of the taller buildings cluster around the more solid bedrock areas closer to downtown. But the engineering principles needed here aren't unknown--cities like Las Vegas and New Orleans have modern buildings that are much taller than were thought possible in earlier times. If the developers didn't do it right because it was expensive, then it is on them.
  - was_boring 10y ago
    To add on, Chicago and New Orleans are both built on swamps, and the outer edges of New York are filled in -- making land for cities isn't the issue with the tower.
    - Animats 10y ago
      The tallest buildings in Chicago have foundations drilled down to bedrock. The Sears Tower (now Willits Tower) is built on bedrock. The Trump Tower [1] has pilings down to bedrock. The John Hancock building has foundations down to bedrock, even though they had to go down almost 200 feet.[2] How unusual is 83 floors in earthquake country without foundations down to bedrock? [1] http://faculty.arch.tamu.edu/media/cms_page_media/4433/trumptowechicago.pdf http://faculty.arch.tamu.edu/media/cms_page_media/4433/trump... [2] http://khan.princeton.edu/khanHancock.html http://khan.princeton.edu/khanHancock.html
chiefalchemist 10y ago
"the building is located on unstable mud-fill, just off the bay’s original shoreline." Nuff said.
chiefalchemist 10y ago
"the building is located on unstable mud-fill, just off the bay’s original shoreline." Nuff said.
spikels 10y ago
Lots of misinformation in this thread. Would be great to hear from a professional.
- vonmoltke 10y ago
  What here is misinformation?
  - spikels 10y ago
    A few examples: - Foundations of tall building must go to bedrock - not true. - Large buildings settling is unusual - not true. - Earthquake safety has been compromised in this case - not true. The structural engineering of tall buildings is complex. Multiple large engineering firms were involved in the design and construction of this building. Curbed (owned by Vox BTW) took the SF Cronicle article and cut out the more reasonable paragraphs (such as that same Stanford they quoted saying he "doesn’t consider the sink or tilt a safety issue".).. And of course the Chron article already probably skewed it to make it more exciting. I always shake my head when I read article on a subject that I happen to be be an expert. I'm sure experts in the engineering of these sorts of projects could teach us alot about this situation.
    - tedunangst 10y ago
      I see a lot more comments asking if earthquake safety has been compromised than comments saying that it has.
    - erdevs 10y ago
      It seems that you need to read more carefully and perhaps with more generosity. > A few examples: - Foundations of tall building must go to bedrock - not true. I see few if any comments here asserting, let alone asserting without qualification, that buildings must be built to bedrock. Further, heeding your own advice that expertise should be bidden, note that the apparently expert sources in the article said themselves that not building to bedrock can be a problem. I see people here noting and reflecting that expert opinion. Few if anyone going beyond it. And you're not reading the source material carefully enough if you miss the take that not building to bedrock can carry some risk. > - Large buildings settling is unusual - not true. Again, I see no one or very few people here saying this. Of course buildings settle over time. And here in this thread, contrary to your blithe and dismissive assertion, we even have people pointing out that settling happens not just in towers but in buildings of most any kind. Note as well, again, that the very experts you appeal to say that this tower's settling is both comparatively fast and that its magnitude is unexpected. These are the experts talking, so you come off as hypocritical at best here. The nature and particulars of the settling in this particular case appears noteworthy and to be a reasonable cause for concern. > - Earthquake safety has been compromised in this case - not true. Ahh... so, now you are the expert and capable of refuting this possibility so entirely-- upon merely a cursory examination of second- or third-hand information, rather than a primary analysis, no less-- that it is somehow faulty for people to question whether this might have an impact on earthquake safety? My, my; odd that you called for caution in drawing conclusions until experts had weighed in, then turned around and flatly conclude that which I doubt even experts would leave completely unqualified, and certainly not universally and unanimously so. The comments here so far are not much of the chicken-little or even rabble-rousing type. Try being more respectful toward your fellow community members.
Overtonwindow 10y ago
Makes me a little thankful (for once) that my Georgia home is built on a hill of dense, unyielding clay.
- blantonl 10y ago
  Dense clay might be unyielding, but depending on the plasticity of that clay you could be facing serious issues with heaving when the soil gets extremely moist.
shirro 10y ago
Surely the first rule of building large buildings in earthquake zones has to be solid foundations. Isn't liquefaction a concern?
davidw 10y ago
Perhaps they can turn it into a tourist attraction. It has worked out well for Pisa.
Johnny555 10y ago
Probably the residents have a lot of books, and the architect forgot to account for the weight of the books. http://www.snopes.com/college/halls/sinking.asp http://www.snopes.com/college/halls/sinking.asp
rwallace 10y ago
"it's not steel-framed and instead uses a concrete design" I thought concrete buildings without steel frames came down instantly in earthquakes. What am I missing?
- zbyte64 10y ago
  ... A big enough earthquake
- jessaustin 10y ago
  Steel reinforcement inside concrete is not the same as a steel frame outside concrete?
- pja 10y ago
  I thought concrete buildings without steel frames came down instantly in earthquakes. What am I missing? Concrete buildings without sufficient bracing at the corners where supporting beams meet floors fail pretty much instantly in earthquakes for sure, but if you put bracing supports in at the corners then that makes them much, much stronger. You’re probably thinking that concrete buildings just collapse from your experience of post-earthquake film footage from countries with poor governance where building firms can cheap out on the construction (lets save 15% of our material costs by skipping the bracing!) and their buildings inevitably collapse when the next earthquake comes along.
RGamma 10y ago
This brings me back to a question I have frequently asked myself: What do you do with unsafe or old skyscrapers? How would you raze such a thing? What if it falls over, breaks apart or breaks in on itself (9/11 gives an idea)? To a layman (with slight acrophobia) skyscrapers seem pretty fragile, and I'd much rather have them built into the ground than towards the sky, but obviously they're holding up in general and I'm interested to see what happens with this one: Hope that it stops tilting or sinking? Raze it before anything bad happens?
- spectre 10y ago
  I did a bit of work on a 28 story building that developed a 1.5m lean during an Earthquake. The story of the demolition http://www.ward-demolition.co.nz/grand-chancellor/ http://www.ward-demolition.co.nz/grand-chancellor/
- JonRB 10y ago
  As a fellow layman I imagine that's where incredibly skilled demolition work comes in. There are some wonderful videos of very precise building demolitions out there.
- ChoGGi 10y ago
  Slowly? https://www.youtube.com/watch?v=jwf9LoS9Xt8 https://www.youtube.com/watch?v=jwf9LoS9Xt8
  - overcast 10y ago
    That's INSANE.
  - TheSpiceIsLife 10y ago
    Wonderful! Thanks for sharing that. I work in the steel construction industry, we put buildings up all day every day, so watching them come down always interests me.
jpeg_hero 10y ago
I heard that there is already a $100m+ compensation fund in place for owners who agree not to sue. Any other information?
- erdevs 10y ago
  If this is true, then it's a big tacit admission of guilt, or the expectation if being found liable, at least. Where did you hear?
skeletonjelly 10y ago
Would be interested to see a video of water being poured onto a flat surface inside this building
andylang_ 10y ago
to quote Stewart Lee: "as a piece of architecture, that is abysmal. But as an extremely heavy-handed satire of exactly where we're going wrong, superb."
3327 10y ago
OUch. Big write down to the yuppies who bot into this glass brogrammer tower.
ams6110 10y ago
Reminds me a bit of the CitiCorp Center fiasco. http://failures.wikispaces.com/Citicorp+Center http://failures.wikispaces.com/Citicorp+Center Not only did the architect miscalculate the worst-case wind load on the building but the builder substituted cheaper bolted steel connections for the originally-specified fully welded connections. The problem was remediated by heavily reinforcing the connections of the diagonal steel braces in the frame of the building, but until it was done there was a very real chance of the building blowing over.
- clintonb 10y ago
  99% Invisible has a story on that building, and how the issue was discovered: http://99percentinvisible.org/episode/structural-integrity/ http://99percentinvisible.org/episode/structural-integrity/.
- MichaelApproved 10y ago
  It was hurricane season and the repairs were done as a major storm was approaching. > Three Meteorological experts were retained to provide updates three times throughout a day. An emergency evacuation plan was developed in conjunction with local law enforcement, search and rescue, firefighters, major city authority figures, and shelters. 2000 emergency red cross workers were kept on stand-by in the event of a failure.
jordanlev 10y ago
> While the Millennium Tower’s sinkage into the earth is reportedly not a safety issue for residents, it does pose a problem for investors. This is confusing to me -- if it's not a safety issue, then why is it a problem?
- PhasmaFelis 10y ago
  The Leaning Tower of Pisa, for example, has stood without toppling for many centuries, but it's not a place you'd want to live in. I also suspect that people with the kind of money they're looking for are not going to accept "don't worry, we checked and it's definitely 100% safe!"
- chillydawg 10y ago
  Given the choice between two identical apartments in two buildings, one of which is rated "safe" but is tilting, you'd prefer the non-tilting one. I definitely would. Bollocks to the safety rating, I want my building straight and not sinking, please!
tomc1985 10y ago
Wouldn't 16 inches warp the surrounding pavement and street? I imagine there'd be a large dip.
trhway 10y ago
a nearby tower under construction - Fremont 181 - has been drilled 260 feet into the ground, well reaching the bedrock. http://sf.curbed.com/2016/8/1/12343776/sinking-millennium-tower http://sf.curbed.com/2016/8/1/12343776/sinking-millennium-to...
wallflower 10y ago
In contrast, the Salesforce tower under construction at 415 Mission Street is built on piles that connect to bedrock. > In a big earthquake, the ground is actually trying to slip sideways underneath the building. “You need something to keep you from changing addresses,” says Joseph. Those somethings are called piles, in essence underground stilts connecting the building with the bedrock. In the lowlands of San Francisco’s Financial District, bedrock is 300 below street level. “We have 42 piles that go all the way down and are socketed 15 to 25 foot deep into the rock,” says Tymoff. http://www.wired.com/2015/11/it-took-18-hours-to-pour-san-franciscos-biggest-ever-concrete-foundation/ http://www.wired.com/2015/11/it-took-18-hours-to-pour-san-fr... And this was part of the proposal from the very beginning. > The Transit Tower would have a concrete slab foundation supported by driven piles anticipated to be founded on bedrock more than 200 feet below grade. The tower’s structural system is anticipated to employ the concept of “megacolumns,” which are very large structural columns several feet in width. The concentrated load supported by these megacolumns would be sustained by large diameter piles approximately 10 feet in diameter, with additional piles driven to support the building’s foundation slab. http://sfrecpark.org/wp-content/uploads/00_FEIR_Draft-1_12-0629_CD_reduced.pdf http://sfrecpark.org/wp-content/uploads/00_FEIR_Draft-1_12-0...
walrus01 10y ago
Reminds me of this: https://en.m.wikipedia.org/wiki/Ocean_Tower https://en.m.wikipedia.org/wiki/Ocean_Tower
- jobigoud 10y ago
  Hmm, they imploded it after discovering it had sunken 14 inches. Millennium Tower has sunken 16 inches…
  - duaneb 10y ago
    I figure it was due to the cracked supports.
ternbot 10y ago
Maybe the buildings are not shifting but the world is shifting and the buildings are actually well built and staying in the same place? People, especially environmentalists, are quick to blame millennial developers. Mother Earth can take the blame here!
ternbot 10y ago
Maybe the buildings are not shifting but the world is shifting and the buildings are actually well built and staying in the same place? People, especially environmentalists, are quick to blame millennial developers. Mother Earth can take the blame here!
SeanDav 10y ago
> "The Millennium’s engineers anchored the building over a thick concrete slab with piles driven roughly 80 feet into dense sand. "To cut costs, Millennium did not drill piles to bedrock,"... They built a skyscraper, on sand, in an earthquake zone!!! What the heck were they thinking? Consider me completely unsurprised that the building is sinking and tilting.
- raverbashing 10y ago
  > They built a skyscraper, on sand, in an earthquake zone!!! What the heck were they thinking? My guess is that they were thinking of something that starts with "pro" and ends with "fit" I mean, Tokyo is earthquake zone, but it's not unsupported sandy soil
SagelyGuru 10y ago
Surely, the tilting is the biggest worry. Anybody care to estimate how many more inches can this tall building tilt before the lateral stresses lead to its collapse?
- huuu 10y ago
  I think you would be amazed how far it could tilt before it collapses. For example the Tower of Pisa (55m height) is leaning much worse: almost 4 meters. https://en.wikipedia.org/wiki/List_of_leaning_towers https://en.wikipedia.org/wiki/List_of_leaning_towers
arxpoetica 10y ago
The wise man built his house upon the rock...
dsfyu404ed 10y ago
FWIW building on sand isn't all that bad if you design the building expecting it to be on sand. The Nazis build AA defenses on sand because a concrete building that's sandwiched between the recoil of small artillery and bedrock won't be around very long. The sand acts like a damper. It's harder to break a cinder block with a hammer if the block is sitting on a pile of sand than if it's on a paved surface and you can apply the same principal at scale if you've got the resources to do all the prerequisite work. It's not that exotic of a design when you consider that the ground under California tends to move around. Too bad it doesn't look like this building was meant to support itself atop a less than solid underlayment. Too bad for the developers.\s If they have to take corrective action they only get a crazy profit margin instead of an insane one. Should have done it right the first time.

268 points by lelf 10y ago

Pretty sure they need to safely dismantle this building and try again. In non-earthquake prone areas, it might make sense to jack it up and what not, but not in SF.

dpark 10y ago
There is no scenario in which a 350 million dollar skyscraper deemed "not a safety issue for residents" will be torn down so they can "try again". They'll find a way to stabilize it and that will be that. No one is going to tear down nearly half a billion dollars worth of skyscraper if there's any chance of salvaging it.
- nostromo 10y ago
  It's not without precedent. In Seattle a cost-cutting method was used to build a 25-story downtown apartment building in 2001. In 2010 it was found to be flawed and unfixable, and so it was dismantled. And now there's a new building being built on the site. http://www.seattletimes.com/seattle-news/9-year-old-belltown-high-rise-too-flawed-to-fix/ http://www.seattletimes.com/seattle-news/9-year-old-belltown...
  - dpark 10y ago
    Key there is it was deemed unfixable. $350 MM can do a lot of fixing. Edit: To be clear, I'm not denying the entire possibility. It's just extremely unlikely, especially given that the tower is currently deemed safe.
    - spikels 10y ago
      Plus if it turns out to have been caused by the Trans Bay Terminal, they have very deep pockets (they supposedly spent $58 million on a buttress to protect the Millineum Tower). As does the developer, Millennium Partners and the engineering from firm's insurance companies. This will get fixed. There will just have to be a big fight to see who has to pay.

pnevares 10y ago

A fair warning that sinking doesn't just happen to towers: http://science.time.com/2012/05/21/soaring-to-sinking-how-building-up-is-bringing-shanghai-down/ http://science.time.com/2012/05/21/soaring-to-sinking-how-bu...

cheeze 10y ago

What is the risk? Does this make the building more dangerous because it's in an earthquake-prone area? Obviously this doesn't sound good, but the article mentions that there is no threat to safety of occupants. Is it merely aesthetic?

simulate 10y ago
This other article discusses how uneven sinking of the tower causes cracks and elevator issues: http://www.sfchronicle.com/bayarea/article/SF-s-landmark-tower-for-rich-and-famous-is-8896563.php http://www.sfchronicle.com/bayarea/article/SF-s-landmark-tow... > And while Stanford’s Deierlein doesn’t consider the sink or tilt a safety issue, he did say, “I would be concerned for my investment.” That’s because a shifting building can cause walls to crack, elevators to malfunction and all manner of other annoyances.
erdevs 10y ago
How much stock should one put in that declaration of safety? It is from an "independent" analysis... but who paid the analysts? Or, suppose absolute freedom from bias... how many times have expert opinions of safety been wrong in the face of mother nature. Picture Fukushima. The risks in a tilting building are many. From a market value standpoint, homeowner value has already been destroyed simply by perception. If remediation is necessary here, homeowner fees could dramatically increase. Tilting buildings often see cracks in walls, malfunctioning elevators and other ills which also lower value. There will be lawsuits here-- you can see all sides rattling sabers with legalistic language and positioning already just from these articles -- and those will carry costs as well. Taxpayers may well be pulled into the fray and suffer as well in these situations. From a pure safety standpoint, experience dictates that we should discount expert declarations of safety in many such matters. Residents of the tower and the towers' neighbors may do well to heed caution. At the end of the day, it is hubris to expect to predict with any high degree of confidence what might happen here. After all, none of the experts from any side involved foresaw even the current predicament, where no grand act of nature is even involved. The building simply stands there, yet already reacts in unpredicted ways. How likely are the experts then to foresee predicaments in even more complex situations?

sharpercoder 10y ago

I wonder what effect a medium to heavy earthquake would have on this building's foundation.

erdevs 10y ago
Probably not good. According to this and other articles, the building's concrete slab foundation sits roughly 80 ft below street level upon sand, while bedrock lies 200 ft down. That means there is 120 ft of sand, possibly susceptible to liquefaction, between the buildings foundation and solid bedrock. That sounds bad enough. But now imagine the building is tipping over slightly. The already potentially worrisome problem compounds dramatically.
- clock_tower 10y ago
  How much would it have cost to dig down to bedrock, and pour a concrete foundation from the bedrock up to surface level? Between the amount of sand to be moved and the amount of concrete to be poured, it sounds like an enormous fortune; I guess that the relevant questions are whether the market could bear it and whether it would be cheaper than the rapidly-developing lawsuits. It may be that the building didn't make economic sense in the first place, if it couldn't be built both safely and profitably -- which has unpleasant implications for the SF housing crunch...
  - WalterBright 10y ago
    The real problem with digging down to bedrock is destablizing the building. Though there may be enough redundancy in the pilings to do it one at a time.
    - vonmoltke 10y ago
      I think the question was why the builders didn't do it in the first place.
      - 10y ago

WalterBright 10y ago

My house is on a steep hill, and Seattle has a reputation for hills sliding away under heavy rain. Before building it, I hired 3 separate geologists to evaluate the site. After digging holes, they said the site was sitting on "glacial till", which is clay that was compacted by about a mile of ice, and said there was nothing to worry about. Paying them was worth it for the peace of mind. (Turns out the till was so hard it could not be dug with hand tools.) I did have a scare because a spring appeared on the edge of the property, as underground water is indicative of slide risk. Fortunately, it turned out to be a leak in the water main! I still made sure the hard surfaces all drained into the storm drain, so that the hill wouldn't become saturated with water. I can't conceive of building a 58 story building on sand in an earthquake zone. Reminds me of that Monty Python quote: "When I first came here, this was all swamp. Everyone said I was daft to build a castle on a swamp, but I built in all the same, just to show them. It sank into the swamp. So I built a second one. That sank into the swamp. So I built a third. That burned down, fell over, then sank into the swamp. But the fourth one stayed up. And that's what you're going to get, Lad, the strongest castle in all of England."

clock_tower 10y ago
Building a large edifice on sand? Put that starkly, I could swear that I heard a story about it once. No idea where, though. ;)
- PhasmaFelis 10y ago
  I recall a Sunday School song to that effect, with hand gestures. "Theeeeeeeeee foolish man built his house upon the sand, the foolish man built his house upon the sand..."
WalterBright 10y ago
One of the geologists told me a simple way to judge the slide risk. Look at the tree trunks. If tree trunks are leaning, or are curved, that indicates the ground under them is shifting.
- 10y ago

qq66 10y ago

16 inches over 8 years is absolutely insane. That's the Usain Bolt of a sinking building.

buckbova 10y ago
Reminded me of the Mandalay Bay incident some years ago. Apparently they tried to cheap out and use a previous soils report from an adjacent area. > The tower was sinking ½ to ¾ inches a week http://traveltips.usatoday.com/mandalay-bay-history-10712.html http://traveltips.usatoday.com/mandalay-bay-history-10712.ht...
torgoguys 10y ago
And the article mentions it was 10 inches in only (it's first) 2 years after completion!
- matthewowen 10y ago
  Good news, the sinking is slowing! :/
  - PhasmaFelis 10y ago
    If the pilings go down 80 feet, and bedrock is at 200 feet, then worst case you'll still have 46 usable stories!

philip1209 10y ago

"To cut costs, Millennium did not drill piles to bedrock." What are the implications for earthquake safety?

helmett 10y ago
I'm sure the engineers ran the calculations and deemed it 'safe enough'
- jonathankoren 10y ago
  Or some investor did.
  - Gracana 10y ago
    Investors will always want things cheaper, and they don't understand engineering. The responsibility of ensuring that the design is safe falls on the engineer who stamped the drawing. Situations like this are covered in engineering ethics classes, which most civil engineers in the US would have taken.
    - r_smart 10y ago
      Plus, depending on the state, a Professional Engineer (a certification earned) has to sign off on this stuff and is liable in the event of something catastrophic happening, like the building falling over.
mcguire 10y ago
Not a geologist, but I suspect that'll depend on how liquid the 120' of sand between the piles and the bedrock gets.
capkutay 10y ago
Because Millennium is on reclaimed land, they cannot determine whether or not they have drilled into bedrock. They drill into what's called the 'point of refusal'; a point where they can no longer drill deeper. Whether this is bedrock or even stable soil is somewhat vague.

helmett 10y ago

...2 inches for such a tall building is such tiny angle If it sinks does this mean the first floor is slightly below the street level ..it probably means that the areas around the door and where the concete meets the street are cracked

carleverett 10y ago
I was wondering the same thing, but Google street view (taken in 2014) doesn't show any evidence of such a big dip. How is that possible?? The only thing I can think of is that it's more of a "sag," where the middle has sunk 18" but the edges haven't moved much, but I'm not really satisfied with that theory. https://www.google.com/maps/place/Millennium+Tower+San+Francisco/@37.7901875,-122.3962408,3a,90y,237.99h,64.97t/data=!3m8!1e1!3m6!1s-35rB20DzRME%2FU7BvmBlYzUI%2FAAAAAAAAKgs%2FidvFTvbnBG4BG0iCULQUc1scg2DlGAkaw!2e4!3e11!6s%2F%2Flh5.googleusercontent.com%2F-35rB20DzRME%2FU7BvmBlYzUI%2FAAAAAAAAKgs%2FidvFTvbnBG4BG0iCULQUc1scg2DlGAkaw%2Fw203-h101-n-k-no%2F!7i11884!8i5942!4m5!3m4!1s0x0:0x9fe15ebd4a8300d8!8m2!3d37.7905058!4d-122.3961611!6m1!1e1 https://www.google.com/maps/place/Millennium+Tower+San+Franc...
- dpark 10y ago
  It's extremely unlikely that the building is sinking and the surrounding area is stable. More likely the building is pulling the entire area down, so it's probably hard to detect as a pedestrian.
  - Naritai 10y ago
    A commenter upstream reports seeing the sidewalk being repaired multiple times throughout the last 10 years as well.
tedunangst 10y ago
Wouldn't the width be a more appropriate measure than height?
- Ankaios 10y ago

djsumdog 10y ago

The article doesn't talk about the how this practically affects the entrances to the building. Do the doors have to be adjusted for such a drastic sinkage, or are buildings somehow designed so this isn't noticeable to the public?

VonGuard 10y ago
Seems to imply they had to do something to the entrances, but not what. Maybe there are little ramps added every year? I'm gonna go look now.
- jonah 10y ago
  Please take some pictures and share them with us. Another article I read said they have needed to make adjustments to the first floor interface but didn't say what they were.
  - deleted 10y ago
    [deleted]
zubat 10y ago
I don't know what skyscrapers do but throughout SF one can find smaller houses that have subsided. They dealt with the problem by adjusting the sidewalk and adding ramps, some of which are absurdly steep now.
- duaneb 10y ago
  That explains so much.
pmontra 10y ago
The sidewalk around the building is sinking with it. See this video https://youtu.be/WMutQBXj5X4 https://youtu.be/WMutQBXj5X4

Animats 10y ago

From the article: "To cut costs, Millennium did not drill piles to bedrock." I'm amazed that a building of that height would be built on a slab with friction piles in the mudflat fill zone of the SF bay. How did they get a building permit for that? 16 inches of sinkage in 8 years is huge. Building sinkage isn't all that unusual, but not for skyscrapers. There was a time when skyscrapers were only built on competent rock, like NYC's. Now they're being built on much more iffy soils. Singapore and some other coastal Asian cities are doing a lot of this. SF used to be smaller. The outer half mile or so on the bay side is fill. There are buried shipwrecks all through that area.[1] [1] https://medium.com/the-secret-history-of-america/from-starboard-to-shot-glass-941b8a863c69#.8r2p8rewz https://medium.com/the-secret-history-of-america/from-starbo...

Finnucane 10y ago
Most of our big coastal cities are like that. Boston is about twice as big as it was in colonial times; all of the Back Bay is landfill. A lot of Cambridge is landfill. And yes, most of the taller buildings cluster around the more solid bedrock areas closer to downtown. But the engineering principles needed here aren't unknown--cities like Las Vegas and New Orleans have modern buildings that are much taller than were thought possible in earlier times. If the developers didn't do it right because it was expensive, then it is on them.
- was_boring 10y ago
  To add on, Chicago and New Orleans are both built on swamps, and the outer edges of New York are filled in -- making land for cities isn't the issue with the tower.
  - Animats 10y ago
    The tallest buildings in Chicago have foundations drilled down to bedrock. The Sears Tower (now Willits Tower) is built on bedrock. The Trump Tower [1] has pilings down to bedrock. The John Hancock building has foundations down to bedrock, even though they had to go down almost 200 feet.[2] How unusual is 83 floors in earthquake country without foundations down to bedrock? [1] http://faculty.arch.tamu.edu/media/cms_page_media/4433/trumptowechicago.pdf http://faculty.arch.tamu.edu/media/cms_page_media/4433/trump... [2] http://khan.princeton.edu/khanHancock.html http://khan.princeton.edu/khanHancock.html

chiefalchemist 10y ago

"the building is located on unstable mud-fill, just off the bay’s original shoreline." Nuff said.

chiefalchemist 10y ago

"the building is located on unstable mud-fill, just off the bay’s original shoreline." Nuff said.

spikels 10y ago

Lots of misinformation in this thread. Would be great to hear from a professional.

vonmoltke 10y ago
What here is misinformation?
- spikels 10y ago
  A few examples: - Foundations of tall building must go to bedrock - not true. - Large buildings settling is unusual - not true. - Earthquake safety has been compromised in this case - not true. The structural engineering of tall buildings is complex. Multiple large engineering firms were involved in the design and construction of this building. Curbed (owned by Vox BTW) took the SF Cronicle article and cut out the more reasonable paragraphs (such as that same Stanford they quoted saying he "doesn’t consider the sink or tilt a safety issue".).. And of course the Chron article already probably skewed it to make it more exciting. I always shake my head when I read article on a subject that I happen to be be an expert. I'm sure experts in the engineering of these sorts of projects could teach us alot about this situation.
  - tedunangst 10y ago
    I see a lot more comments asking if earthquake safety has been compromised than comments saying that it has.
  - erdevs 10y ago
    It seems that you need to read more carefully and perhaps with more generosity. > A few examples: - Foundations of tall building must go to bedrock - not true. I see few if any comments here asserting, let alone asserting without qualification, that buildings must be built to bedrock. Further, heeding your own advice that expertise should be bidden, note that the apparently expert sources in the article said themselves that not building to bedrock can be a problem. I see people here noting and reflecting that expert opinion. Few if anyone going beyond it. And you're not reading the source material carefully enough if you miss the take that not building to bedrock can carry some risk. > - Large buildings settling is unusual - not true. Again, I see no one or very few people here saying this. Of course buildings settle over time. And here in this thread, contrary to your blithe and dismissive assertion, we even have people pointing out that settling happens not just in towers but in buildings of most any kind. Note as well, again, that the very experts you appeal to say that this tower's settling is both comparatively fast and that its magnitude is unexpected. These are the experts talking, so you come off as hypocritical at best here. The nature and particulars of the settling in this particular case appears noteworthy and to be a reasonable cause for concern. > - Earthquake safety has been compromised in this case - not true. Ahh... so, now you are the expert and capable of refuting this possibility so entirely-- upon merely a cursory examination of second- or third-hand information, rather than a primary analysis, no less-- that it is somehow faulty for people to question whether this might have an impact on earthquake safety? My, my; odd that you called for caution in drawing conclusions until experts had weighed in, then turned around and flatly conclude that which I doubt even experts would leave completely unqualified, and certainly not universally and unanimously so. The comments here so far are not much of the chicken-little or even rabble-rousing type. Try being more respectful toward your fellow community members.

Overtonwindow 10y ago

Makes me a little thankful (for once) that my Georgia home is built on a hill of dense, unyielding clay.

blantonl 10y ago
Dense clay might be unyielding, but depending on the plasticity of that clay you could be facing serious issues with heaving when the soil gets extremely moist.

shirro 10y ago

Surely the first rule of building large buildings in earthquake zones has to be solid foundations. Isn't liquefaction a concern?

davidw 10y ago

Perhaps they can turn it into a tourist attraction. It has worked out well for Pisa.

Johnny555 10y ago

Probably the residents have a lot of books, and the architect forgot to account for the weight of the books. http://www.snopes.com/college/halls/sinking.asp http://www.snopes.com/college/halls/sinking.asp

rwallace 10y ago

"it's not steel-framed and instead uses a concrete design" I thought concrete buildings without steel frames came down instantly in earthquakes. What am I missing?

zbyte64 10y ago
... A big enough earthquake
jessaustin 10y ago
Steel reinforcement inside concrete is not the same as a steel frame outside concrete?
pja 10y ago
I thought concrete buildings without steel frames came down instantly in earthquakes. What am I missing? Concrete buildings without sufficient bracing at the corners where supporting beams meet floors fail pretty much instantly in earthquakes for sure, but if you put bracing supports in at the corners then that makes them much, much stronger. You’re probably thinking that concrete buildings just collapse from your experience of post-earthquake film footage from countries with poor governance where building firms can cheap out on the construction (lets save 15% of our material costs by skipping the bracing!) and their buildings inevitably collapse when the next earthquake comes along.

RGamma 10y ago

This brings me back to a question I have frequently asked myself: What do you do with unsafe or old skyscrapers? How would you raze such a thing? What if it falls over, breaks apart or breaks in on itself (9/11 gives an idea)? To a layman (with slight acrophobia) skyscrapers seem pretty fragile, and I'd much rather have them built into the ground than towards the sky, but obviously they're holding up in general and I'm interested to see what happens with this one: Hope that it stops tilting or sinking? Raze it before anything bad happens?

spectre 10y ago
I did a bit of work on a 28 story building that developed a 1.5m lean during an Earthquake. The story of the demolition http://www.ward-demolition.co.nz/grand-chancellor/ http://www.ward-demolition.co.nz/grand-chancellor/
JonRB 10y ago
As a fellow layman I imagine that's where incredibly skilled demolition work comes in. There are some wonderful videos of very precise building demolitions out there.
ChoGGi 10y ago
Slowly? https://www.youtube.com/watch?v=jwf9LoS9Xt8 https://www.youtube.com/watch?v=jwf9LoS9Xt8
- overcast 10y ago
  That's INSANE.
- TheSpiceIsLife 10y ago
  Wonderful! Thanks for sharing that. I work in the steel construction industry, we put buildings up all day every day, so watching them come down always interests me.

jpeg_hero 10y ago

I heard that there is already a $100m+ compensation fund in place for owners who agree not to sue. Any other information?

erdevs 10y ago
If this is true, then it's a big tacit admission of guilt, or the expectation if being found liable, at least. Where did you hear?

skeletonjelly 10y ago

Would be interested to see a video of water being poured onto a flat surface inside this building

andylang_ 10y ago

to quote Stewart Lee: "as a piece of architecture, that is abysmal. But as an extremely heavy-handed satire of exactly where we're going wrong, superb."

3327 10y ago

OUch. Big write down to the yuppies who bot into this glass brogrammer tower.

ams6110 10y ago

Reminds me a bit of the CitiCorp Center fiasco. http://failures.wikispaces.com/Citicorp+Center http://failures.wikispaces.com/Citicorp+Center Not only did the architect miscalculate the worst-case wind load on the building but the builder substituted cheaper bolted steel connections for the originally-specified fully welded connections. The problem was remediated by heavily reinforcing the connections of the diagonal steel braces in the frame of the building, but until it was done there was a very real chance of the building blowing over.

clintonb 10y ago
99% Invisible has a story on that building, and how the issue was discovered: http://99percentinvisible.org/episode/structural-integrity/ http://99percentinvisible.org/episode/structural-integrity/.
MichaelApproved 10y ago
It was hurricane season and the repairs were done as a major storm was approaching. > Three Meteorological experts were retained to provide updates three times throughout a day. An emergency evacuation plan was developed in conjunction with local law enforcement, search and rescue, firefighters, major city authority figures, and shelters. 2000 emergency red cross workers were kept on stand-by in the event of a failure.

jordanlev 10y ago

> While the Millennium Tower’s sinkage into the earth is reportedly not a safety issue for residents, it does pose a problem for investors. This is confusing to me -- if it's not a safety issue, then why is it a problem?

PhasmaFelis 10y ago
The Leaning Tower of Pisa, for example, has stood without toppling for many centuries, but it's not a place you'd want to live in. I also suspect that people with the kind of money they're looking for are not going to accept "don't worry, we checked and it's definitely 100% safe!"
chillydawg 10y ago
Given the choice between two identical apartments in two buildings, one of which is rated "safe" but is tilting, you'd prefer the non-tilting one. I definitely would. Bollocks to the safety rating, I want my building straight and not sinking, please!

tomc1985 10y ago

Wouldn't 16 inches warp the surrounding pavement and street? I imagine there'd be a large dip.

trhway 10y ago

a nearby tower under construction - Fremont 181 - has been drilled 260 feet into the ground, well reaching the bedrock. http://sf.curbed.com/2016/8/1/12343776/sinking-millennium-tower http://sf.curbed.com/2016/8/1/12343776/sinking-millennium-to...

wallflower 10y ago

In contrast, the Salesforce tower under construction at 415 Mission Street is built on piles that connect to bedrock. > In a big earthquake, the ground is actually trying to slip sideways underneath the building. “You need something to keep you from changing addresses,” says Joseph. Those somethings are called piles, in essence underground stilts connecting the building with the bedrock. In the lowlands of San Francisco’s Financial District, bedrock is 300 below street level. “We have 42 piles that go all the way down and are socketed 15 to 25 foot deep into the rock,” says Tymoff. http://www.wired.com/2015/11/it-took-18-hours-to-pour-san-franciscos-biggest-ever-concrete-foundation/ http://www.wired.com/2015/11/it-took-18-hours-to-pour-san-fr... And this was part of the proposal from the very beginning. > The Transit Tower would have a concrete slab foundation supported by driven piles anticipated to be founded on bedrock more than 200 feet below grade. The tower’s structural system is anticipated to employ the concept of “megacolumns,” which are very large structural columns several feet in width. The concentrated load supported by these megacolumns would be sustained by large diameter piles approximately 10 feet in diameter, with additional piles driven to support the building’s foundation slab. http://sfrecpark.org/wp-content/uploads/00_FEIR_Draft-1_12-0629_CD_reduced.pdf http://sfrecpark.org/wp-content/uploads/00_FEIR_Draft-1_12-0...

walrus01 10y ago

Reminds me of this: https://en.m.wikipedia.org/wiki/Ocean_Tower https://en.m.wikipedia.org/wiki/Ocean_Tower

jobigoud 10y ago
Hmm, they imploded it after discovering it had sunken 14 inches. Millennium Tower has sunken 16 inches…
- duaneb 10y ago
  I figure it was due to the cracked supports.

ternbot 10y ago

Maybe the buildings are not shifting but the world is shifting and the buildings are actually well built and staying in the same place? People, especially environmentalists, are quick to blame millennial developers. Mother Earth can take the blame here!

ternbot 10y ago

SeanDav 10y ago

> "The Millennium’s engineers anchored the building over a thick concrete slab with piles driven roughly 80 feet into dense sand. "To cut costs, Millennium did not drill piles to bedrock,"... They built a skyscraper, on sand, in an earthquake zone!!! What the heck were they thinking? Consider me completely unsurprised that the building is sinking and tilting.

raverbashing 10y ago
> They built a skyscraper, on sand, in an earthquake zone!!! What the heck were they thinking? My guess is that they were thinking of something that starts with "pro" and ends with "fit" I mean, Tokyo is earthquake zone, but it's not unsupported sandy soil

SagelyGuru 10y ago

Surely, the tilting is the biggest worry. Anybody care to estimate how many more inches can this tall building tilt before the lateral stresses lead to its collapse?

huuu 10y ago
I think you would be amazed how far it could tilt before it collapses. For example the Tower of Pisa (55m height) is leaning much worse: almost 4 meters. https://en.wikipedia.org/wiki/List_of_leaning_towers https://en.wikipedia.org/wiki/List_of_leaning_towers

arxpoetica 10y ago

The wise man built his house upon the rock...

dsfyu404ed 10y ago

FWIW building on sand isn't all that bad if you design the building expecting it to be on sand. The Nazis build AA defenses on sand because a concrete building that's sandwiched between the recoil of small artillery and bedrock won't be around very long. The sand acts like a damper. It's harder to break a cinder block with a hammer if the block is sitting on a pile of sand than if it's on a paved surface and you can apply the same principal at scale if you've got the resources to do all the prerequisite work. It's not that exotic of a design when you consider that the ground under California tends to move around. Too bad it doesn't look like this building was meant to support itself atop a less than solid underlayment. Too bad for the developers.\s If they have to take corrective action they only get a crazy profit margin instead of an insane one. Should have done it right the first time.