17 ms·

San Francisco’s Seismic Gamble

310 points by montrose 9y ago

deleted 9y ago
[deleted]
kozikow 9y ago
Shameless plug: At my company, tensorflight.com, we use computer vision on satellite/aerial/street view imagery to extract factors used for predicting the earthquake damage. For example, construction type or the number of stories mentioned in the article. Given factors extracted by us, to get the full picture you may use open source catastrophe modelling software, Hazus released by FEMA.
sho 9y ago
This presentation is absolutely fantastic. Hard to remember a better example of digital journalism well used. No gimmicks - just relevant information intuitively presented. Excellent!
- gumby 9y ago
  My mileage aired from yours: I would have been happier simply wth pitctures rather than something that hijacked the scrolling and interrupted the flow of reading. Reading on an iPad fwiw.
  - sho 9y ago
    I actually went and tried it out on an iPad too. I admit it's not as nice an experience - in fact it almost seems buggy, scrolling up past the top of the viewport before the JS notices and suddenly pushes it back down. They could improve that. At least make it less jarring.
briandear 9y ago
> For years the city restricted building height to 500 feet in most neighborhoods. Surely that’s a typo? Because that is kind of insane.
- chrisseaton 9y ago
  That's 150 m, or around 40 stories - that's pretty tall for outside the centre of a city.
- darkerside 9y ago
  Why? That's about a 50 story building.
  - briandear 9y ago
    Because “for years” that was the restriction. That doesn’t sound like much of a restriction. The implication is that it’s restricted less now. The story talked about how San Francisco resisted high rises for a long time, so that restriction doesn’t follow the story — that’s why I think it’s a typo.
  - Zarel 9y ago
    Yes, which is way higher than I'd expect, given SF's general opposition to high-rises. According to Google, the actual limit is 40 feet. Example article I found: https://recklesslyoptimistic.com/san-franciscos-height-restrictions-and-the-city-s-dark-future-c7796fafb07c https://recklesslyoptimistic.com/san-franciscos-height-restr...
    - jandrese 9y ago
      Yeah, if the limit were 500 feet you wouldn't have builders constantly complaining about it.
    - darkerside 9y ago
      Here's another article cutting a height restriction near 500 feet. http://www.structuremag.org/?p=11635 http://www.structuremag.org/?p=11635 There are probably more height restrictions in different areas, and a 500 foot limit is actually quite restrictive. It would have prevented Salesforce Tower. The Empire State Building is over 100 floors.
Tistel 9y ago
Great/Scary article. Has anyone worked in the tilting building? Are there cracks in the walls? Is the soil compaction expected to stop (some max density type thing)? I think they stopped the tower of Pisa tilting by injecting concrete under it. It must be difficult to not exasperate they problem at the start of the injection (I am guessing they have to remove some material first).
- whafro 9y ago
  I knew someone who lived in the building, and while she didn't report cracks in the walls, she did say that things would reliably roll toward one corner of her apartment if they weren't secured.
  - tlb 9y ago
    14 inches over 58 stories works out to 0.10 degrees. That doesn't seem like enough to make anything roll. You might have to shim your billiard table.
    - kowdermeister 9y ago
      A golf ball sounds like something to me: https://www.youtube.com/watch?v=dCUCa0Bvh1k https://www.youtube.com/watch?v=dCUCa0Bvh1k
    - saalweachter 9y ago
      Your floor being on a 0.1 degree slope is a rise of 0.2 inches over 10 feet. Definitely noticeable.
      - jessriedel 9y ago
        Not definitely. The professional standard for levelness in homes and office buildings is F_L ~ 20, where F_L is the levelness "F number". http://www.concretefloors.ca/?page_id=546 http://www.concretefloors.ca/?page_id=546 http://www.betagroupgc.com/Concrete%20International%20-%20The%20Floor%20Flatness%20Report.pdf http://www.betagroupgc.com/Concrete%20International%20-%20Th... The maximum slope b=rise/run compatible with this is b_max = (314 mm/3m)/F_L = .105/F_L ~ 0.005 for F_L = 20, https://www.astmfree.com/wp-content/uploads/2018/01/E-115-M.pdf https://www.astmfree.com/wp-content/uploads/2018/01/E-115-M.... which corresponds to 0.005 radians = 0.3 degrees. Projects like roller rinks and warehouses that use air pallets require more level floors, but typically only by a factor of 2 .
nextstep 9y ago
Reason no. 42614 not to live in the San Francisco Bay Area.
- collyw 9y ago
  42615, you might end up working with Salesforce.
  - andegre 9y ago
    I'm chiming in late in the game here, but what's wrong with Salesforce? (Only reason I ask is because of the piece that I just saw on 60 minutes Sunday night, so your comment piqued my interest)
    - PunchTornado 9y ago
      It's slow AF.
      - notfromhere 9y ago
        Basically ever database SaaS tool is slow AF. They don't tell you that during the sales cycle though
      - aidenn0 9y ago
        AF?
        komali2 9y ago
        as fuck
    - collyw 9y ago
      Development in a web browser. Everything is paginated. A bastardiation of Java and SQL - without joins as the language it uses. An over complicated data model (for the business I had to integrate it with at least. Some things could only be done via SOAP. I had to integrate our existing Django based system with Salesforce. What I expected to take a few days took a few months. Similar syncing of data between another Django based system did take a couple of days. I can't go on, it brings back too many bad memories. If you have ever enjoyed development you will hate Salesforce. It feels like the tech equivalent of digging holes and filling them back in again.
lmilcin 9y ago
It seems shockingly irresponsible that it is allowed to build high rises in areas that can undergo liquefaction. No matter how strong the building is if the ground gives up it must fall over.
- Spooky23 9y ago
  Blame zoning! Shockingly, the people who own property less likely to collapse in an earthquake do not want big buildings next door. So big buildings are being built on harbor fill. What could go wrong?
- elgenie 9y ago
  IIRC the proper way to handle that is by anchoring the foundation of the building to the bedrock underneath the layers which can undergo liquefaction. That's done by means of drilling as deep as necessary to put the foundation and then adding pylons on which the building rests. Depending on how deep the liquefaction-prone layers go, that's could be an option that's realistic only for a high rise.
  - lmilcin 9y ago
    And how does that relate to Millennium tower which has already "sunk a foot and a half"? What if high rise building is anchored through all liquefaction-prone layers but the layers start to shift (they are on slight incline) when they get liquified? I am not expert but I can imagine it is possible that, if the structural support is long enough, just few inches of lateral movement may completely compromise the support.
    - stale2002 9y ago
      Because the millennium tower did NOT do the correct thing, and did not anchor it to bedrock. They would be having problems if they did it the right way.
  - ummonk 9y ago
    Or you can design the building to float on the liquified soil. Either way works.
danielvf 9y ago
This got me wondering what the Salesforce tower’s builders countermeasures were for the soil and seismic issues. Surely they tried to do something. Here’s an article about what they did. (Skip the fluff in first third, it does get down to details later.) http://www.structuremag.org/?p=11635 http://www.structuremag.org/?p=11635
- smoyer 9y ago
  From the diagrams included in that link, it looks like there's going to be a real problem if "the big one" happens during severe gusting winds.
  - onion2k 9y ago
    Even if that isn't the case, the Millennium Tower is literally across the road[1] and could fall in the wrong direction considering "Millennium Tower has sunk almost a foot and a half and is leaning 14 inches toward neighboring high rises" [1] https://www.google.co.uk/maps/place/Millennium+Tower+San+Francisco/@37.7875068,-122.3972696,529a,35y,39.33t/data=!3m1!1e3!4m5!3m4!1s0x0:0x9fe15ebd4a8300d8!8m2!3d37.7905055!4d-122.3962516 https://www.google.co.uk/maps/place/Millennium+Tower+San+Fra...
    - jandrese 9y ago
      Is 14" of lean a lot on a high rise? Certainly that is a small fraction of a degree of total lean. The sinking does seem like a concern and is no doubt related. It seems like someone underestimated how much foundation work would be needed on that building. How does the front door work? Do they have steps down into the lobby now?
    - matte_black 9y ago
      How many inches of lean can a building support before it just falls over WTC style?
      - IAmEveryone 9y ago
cwal37 9y ago
"Right now the code says a structure must be engineered to have a 90 percent chance of avoiding total collapse. But many experts believe that is not enough. “Ten percent of buildings will collapse,” said Lucy Jones, the former leader of natural hazards research at the United States Geological Survey who is leading a campaign to make building codes in California stronger. “I don’t understand why that’s acceptable.”" One way that reads to me is that an event over some threshold has a high probability to cause the complete collapse all of those buildings. 90% doesn't seem like a very high threshold either, if it corresponds straight out to a 1-in-10 event that seems quite bad. If it's a 90% chance of survival in a 1-in-100 event, that's better, but not great.
- jerf 9y ago
  I suspect it would be the latter, similar to other disaster planning. This gets you into that domain where most people really don't like to go, but... you don't get the choice of 100% perfectly likely to stand up, so where do you draw the line? You don't have an alternative. A line will be drawn. If you don't draw one deliberately, you'll draw one accidentally. But if you want to have some fun with ways the probability estimates could be badly broken, correlated failures can be the way to go. Suppose for the sake of argument that there is an earthquake in the future that if each building was subjected to it individually would cause 10% of the buildings to come down. That doesn't mean that 10% of the buildings will fall down in real life, though, because the failures could be correlated and coupled, if one building falling down makes another building falling down more likely. If I'm running the physics and numbers in my head correctly [1], even in an extremely large earthquake the Hollywood image of buildings toppling each other like dominos is still exceedingly unlikely. They'll go down, not sideways. But the additional shocks they create in both the air and the ground in the process could tip some other buildings over the edge. We know from 9/11 that buildings going down can seriously damage other nearby buildings. So, densely packing buildings with a 90% survival rate can result in a net survival rate less than 90%. And of course, if it's 90% at Richter x, there's no law of the universe that says x is the limit. x+1.5 is still perfectly possible. [1]: It's hard to google up the amplitude of an earthquake in a distance measure, rather than Richter scale or something. But it looks like "several centimeters" of transverse motion would be a very large earthquake, which isn't going to put the center of mass of a building out of the area described by its foundations. Which isn't anywhere near a complete description of what it would take to tip a building like a domino, but is enough to say it's a long way from happening. (My guess is that it's actually impossible to tip a tall building like a domino as any possible attempt to exert the forces necessary to do so would itself be enough to destroy the building. See also "why Superman must also be telekinetic", because it doesn't matter how strong you make an 747, there is no place on that plane it can be picked up by any amount of pressure exerted by two human-sized hands without the hands tearing right through the plane, rather than nicely carrying it. (A handful of non-telekinetic Supermans could do it if the plane lowers the landing gear and Supermans support the tires with their backs instead, but that'll be tricky to "fly" in other ways. Especially since the best way to support the plane will be with the Supermans being sideways, to maximize area of contact with the tire.) Similarly, some sort of Superman-esque force that applies equally to all atoms would be required, rather than the real forces we can apply via external pressures.)
0xcafecafe 9y ago
Of all the natural disasters, I seem to shudder at earthquakes the most. May be because I am biased by witnessing the destruction brought by the 2001 earthquake in India. The thought that at any moment, without warning, the safe abode you are in might come crashing down on you is pretty scary. I wonder with human population increasing and with the shortage of urban land needing highrises, what is the long term solution to this.
- f_allwein 9y ago
  The long term solution would be having enough energy to modify the earth enough in order to prevent earthquakes. From http://mkaku.org/home/articles/the-physics-of-extraterrestrial-civilizations/ http://mkaku.org/home/articles/the-physics-of-extraterrestri... : "For example, a Type I civilization is a truly planetary one, which has mastered most forms of planetary energy. Their energy output may be on the order of thousands to millions of times our current planetary output. Mark Twain once said, ”Everyone complains about the weather, but no one does anything about it.“ This may change with a Type I civilization, which has enough energy to modify the weather. They also have enough energy to alter the course of earthquakes, volcanoes, and build cities on their oceans."
  - adrianN 9y ago
    It seems a lot easier to build floating cities than to cool Earth's core enough to stop earthquakes.
    - jacquesm 9y ago
      That would be a very stupid thing to do because it would also stop the Earth magnetic field which helps to shield us from cosmic radiation.
      - adrianN 9y ago
        When we have the technology to cool Earths core(!), we'll also be able to make our own magnetic field.
chiph 9y ago
> The goal of the code, say proponents of a stronger one, should be the survival of cities — strengthening water systems, electrical grids and cellular networks — not just individual buildings. I'm not sure how you'd prevent water & sewer lines from breaking during an earthquake - they're surrounded by earth (or secured along concrete walls in buried vaults) so they're going to get motion & shear all along their length - so not much room to flex. Assuming they were made of a flexible material and not cast iron. One of the reasons why the 1906 earthquake was so devastating were the fires afterwards, where the fire companies couldn't get water.
- ceejayoz 9y ago
  After the 1906 earthquake, SF started adding large, distributed cisterns to store water throughout the city. I'd imagine there are lots of similar sorts of tweaks you could make - more a focus on a distributed, resilient grid than preventing pipe breaks entirely.
  - komali2 9y ago
    Even in 1989 they couldn't get water, they had to suck it out of the bay.
    - ceejayoz 9y ago
      That appears to be part of the water supply plan (makes a lot of sense to use the water they've got there), and the cistern system appears to have partially functioned: http://www.sfmuseum.net/quake/revawss.html http://www.sfmuseum.net/quake/revawss.html > The upper zone of the AWSS, however, functioned normally through the earthquake period, and was used to suppress earthquake-caused fires. Looks like they're building more: http://abc7news.com/news/over-30-cisterns-to-be-built-in-sf-to-prepare-for-earthquake/68515/ http://abc7news.com/news/over-30-cisterns-to-be-built-in-sf-...
mabbo 9y ago
There are always ways to build the tall buildings safely- they're just more expensive. These buildings aren't unsafe because there's no choice, they're unsafe because the builders wanted to save money and the building code was too loose to stop them. Japan is a highly volitile region, tectonically speaking, yet they've managed to build lots of tall buildings safely. How? By having some of the strictest building codes in the world, yet allowing development within those rules. Meanwhile, outside of SF itself, the Bay area refuses to build any real density that's desperately needed, using earthquakes as (one of many) excuses for NIMBYism and entrenched interests of landlords.
- kakwa_ 9y ago
  Also, If I recall correctly, what did the most damages in the 1906 SF earthquake was not the actual earthquake itself. What caused the most damages was the fires after the earthquake. Hopefully SF has a better fire department now than in 1906.
  - ekianjo 9y ago
    same thing for Kobe in 1995. Fires were responsible for most of the deaths.
  - cobbzilla 9y ago
    It's not just the fire department that's better - in 1906 a lot of those fires were caused when the quake would pull a gas appliance from a wall and leave a gas leak that later ignited. Nowadays everyone has their hot water heater and oven bolted or strapped to the wall. I'm sure there are other useful fire codes California has adopted since then but this one rule will probably prevent more fires in the next big quake than any other.
    - JshWright 9y ago
      Additionally, gas fittings that are designed to (safely) breakaway are more common.
    - mturmon 9y ago
deleted 9y ago
[deleted]
JackFr 9y ago
Weird that the word "Japan" occurs 0 times in an article about skyscrapers and earthquakes. I realize the focus of the article is SF, but when the author elaborates on our lack of experience with skyscrapers in earthquakes, with no mention at all of Japan, it makes me think that this is just a clueless scare piece rather than any kind of thoughtful analysis.
- lev99 9y ago
  I'm sure the New York Times has a vested interest in keeping New York the economic powerhouse of the United States and this article directly attacks San Fransisco's best option for economic growth. There are entire careers dedicated to determine buildings ability to survive natural disasters and informing people about the risk. There are entire careers dedicated to finding ways to make buildings more earth quake resistant. It seems like banks, developers, governments, and insurance companies would be listening to both of these professionals very closely before building something one thousand feet high. I would prefer to hear from them than Thomas Fuller of the New York Times.
- vincvinc 9y ago
  Funny, earlier today I just happened to see this Tokyo earthquake footage of skyscrapers swaying violently: https://www.youtube.com/watch?v=ACKMPD6MySs https://www.youtube.com/watch?v=ACKMPD6MySs Then, in the article, I read about San Fransisco: "the issue of seismic safety of high rises was “never a factor” in the redevelopment plans" I can not imagine any positive outcome here.
  - sdrothrock 9y ago
    > Funny, earlier today I just happened to see this Tokyo earthquake footage of skyscrapers swaying violently It's unclear from your comment, so I wanted to clarify for other people who may not know: skyscrapers are intentionally built such that they sway, as that helps to disperse the energy more than a rigid structure. http://www.businessinsider.com/earthquake-resistant-buildings-2011-3#the-e-defense-table-is-a-shifting-base-intended-to-simulate-an-earthquake-7 http://www.businessinsider.com/earthquake-resistant-building... https://earlywarninglabs.com/old/ewl/skyscraper-safety/ https://earlywarninglabs.com/old/ewl/skyscraper-safety/
komali2 9y ago
Those of you actually living / working in the Bay Area, I highly recommend looking into "NERT" - Neighborhood Emergency Response Team[1]. It's about 18 hours of training on disaster preparedness, earthquake safety, triage, and search and rescue. The idea is twofold - the more citizens that can handle themselves and their families for the first 72 hours of a disaster, the more people that have a 72 hour timeline to death (trapped, injured) the professionals can find and rescue. The second is that there is literally no city in the world that has the fire department resources to handle a catastrophic disaster (>8 earthquake, tsunami) without "significant loss," and so trained volunteers can do a great deal to "fill the gap." In the 1989 earthquake untrained volunteers were critical in helping the SFFD get water into hoses [2] when the mains went down. Last count I heard is that there's about 2,000 NERTs now trained in the city. Imagine having 2,000 basic-trained volunteers helping out in a disaster. Incredible. To put it in perspective, there's only about 1,500 employees of the SFFD. There's a city-wide drill this weekend, actually, and they need victim volunteers. If you want to get painted with gruesome injuries and scream at people in green hardhats, it could make for a great time! [4] If you aren't in the bay area, check out the FEMA equivalent, "CERT." [3] [1] http://sf-fire.org/neighborhood-emergency-response-team-nert http://sf-fire.org/neighborhood-emergency-response-team-nert [2] http://cdn.abclocal.go.com/content/kgo/images/cms/349779_1280x720.jpg http://cdn.abclocal.go.com/content/kgo/images/cms/349779_128... [3] https://www.ready.gov/community-emergency-response-team https://www.ready.gov/community-emergency-response-team [4] https://www.eventbrite.com/e/victims-needed-volunteer-for-the-nert-citywide-drill-tickets-44821250567 https://www.eventbrite.com/e/victims-needed-volunteer-for-th... edit- by the way, this training is free, and comes at no obligation to actually run into burning buildings should a disaster happen (they want you to take care of your home, family, and neighbors before anything else)
songzme 9y ago
Apparently South Michigan is the safest place to live from natural disasters: https://www.quora.com/What-is-the-safest-place-to-live-in-the-USA-that-is-least-likely-to-be-effected-by-earthquakes-tsunamis-volcanic-eruptions-or-similar-events#!n=12 https://www.quora.com/What-is-the-safest-place-to-live-in-th...
- anothergoogler 9y ago
  That's just a random Quora user's opinion. Southern MI sees plenty of powerful tornados. For instance https://en.wikipedia.org/wiki/1980_Kalamazoo_tornado https://en.wikipedia.org/wiki/1980_Kalamazoo_tornado and https://www.weather.gov/grr/1965PalmSundayTornado https://www.weather.gov/grr/1965PalmSundayTornado
- zer00eyz 9y ago
  I know what your saying but all I could think of was Flint.
- _jn 9y ago
  IIRC, Las Vegas is also pretty high on that list, hence the data centers.
jasondc 9y ago
I thought the massive water tank at the top of One Rincon Hill , to control swaying in the event of earthquakes, was interesting: https://www.sfgate.com/bayarea/article/One-Rincon-tower-features-water-tank-on-top-to-3299035.php https://www.sfgate.com/bayarea/article/One-Rincon-tower-feat...
- ggcdn 9y ago
  Straight from the article: > The damper system has no connection with the seismic safety of One Rincon. It is always a challenge to build a tall structure in earthquake country, and One Rincon's engineering response was to use outriggers, tall reinforced concrete columns built around the core of the building.
czep 9y ago
"Witnesses on the morning of April 18, 1906, described the city’s streets as rising and falling like a ribbon carried by the wind." "one out of every four buildings in the Bay Area might not be usable after a magnitude 7 earthquake" "At a time when the average price of a home in San Francisco is above $1.2 million..." Why aren't people pricing in an earthquake discount? This is so totally irrational, housing in SF should be cheaper given the certain risk of an earthquake and consequent large probability of severe damage. And even if your house isn't destroyed, good luck finding a contractor post-earthquake. Even now contractors are so hard to find, over priced, and many do shoddy work, I can't imagine why people don't see this coming and stop paying this much for something that may fall down any day now.
- kazinator 9y ago
  > Why aren't people pricing in an earthquake discount? Because it's a matter of insurance, and thus reduced to a recurring premium bill. Why not price all maintenance costs and electricity too? Living in this house for the next fifty years will cost you all these utility bills; you should get a discount from the purchase price to reflect that! :)
  - czep 9y ago
    Few insurers offer earthquake insurance, and those who do charge very hefty premiums, we're talking about adding 50% to the cost of your mortgage over 30 years. Hence, a very small portion of the housing stock in SFBA is insured against quake damage. I still want to know why people aren't thinking about this when they pay so much for a house.
  - banachtarski 9y ago
    Lol nobody has earthquake insurance. It's exorbitantly priced.
    - jiveturkey 9y ago
      11% of homeowners have earthquake coverage in CA. http://www.latimes.com/business/la-fi-agenda-earthquake-insurance-20171002-story.html http://www.latimes.com/business/la-fi-agenda-earthquake-insu... Like all insurance, the price reflects the risk vs the number of buyers. If more people had it, the price would be less exorbitant.
jumelles 9y ago
It's not an if, it's a when. You couldn't pay me enough to live in SF.
davidhegarty 9y ago
Love every opportunity to link to this story: http://www.slate.com/blogs/the_eye/2014/04/17/the_citicorp_tower_design_flaw_that_could_have_wiped_out_the_skyscraper.html http://www.slate.com/blogs/the_eye/2014/04/17/the_citicorp_t... The Citigroup building in NYC had a fundamental design flaw that could cause it to collapse.
- deleted 9y ago
  [deleted]
- bigger_cheese 9y ago
  That story is pretty well known in Engineering circles - we used it as an ethics case study at my Australian University.
product50 9y ago
Very one sided article and full of scaremongering. There is no comparison with building codes of other countries which are earthquake prone (such as JP or TW), only example is provided (Millennium Tower) and it is unclear if liquifaction will only affect skyscrapers or 1-2 storey buildings too.
flyGuyOnTheSly 9y ago
>Previous earthquakes have revealed flaws with some skyscrapers. A widely used welding technique was found to rupture during the 1994 Northridge earthquake in Los Angeles. (Many buildings in San Francisco and Los Angeles have not been retrofitted.) That statement really boggles the mind. How do you own some of the most valuable property in the world, and not maintain it in the simplest of ways against something that could literally destroy your investment? After 24 years of knowing that your building was in danger?

310 points by montrose 9y ago

deleted 9y ago

[deleted]

Shameless plug: At my company, tensorflight.com, we use computer vision on satellite/aerial/street view imagery to extract factors used for predicting the earthquake damage. For example, construction type or the number of stories mentioned in the article. Given factors extracted by us, to get the full picture you may use open source catastrophe modelling software, Hazus released by FEMA.

sho 9y ago

This presentation is absolutely fantastic. Hard to remember a better example of digital journalism well used. No gimmicks - just relevant information intuitively presented. Excellent!

gumby 9y ago
My mileage aired from yours: I would have been happier simply wth pitctures rather than something that hijacked the scrolling and interrupted the flow of reading. Reading on an iPad fwiw.
- sho 9y ago
  I actually went and tried it out on an iPad too. I admit it's not as nice an experience - in fact it almost seems buggy, scrolling up past the top of the viewport before the JS notices and suddenly pushes it back down. They could improve that. At least make it less jarring.

briandear 9y ago

> For years the city restricted building height to 500 feet in most neighborhoods. Surely that’s a typo? Because that is kind of insane.

chrisseaton 9y ago
That's 150 m, or around 40 stories - that's pretty tall for outside the centre of a city.
darkerside 9y ago
Why? That's about a 50 story building.
- briandear 9y ago
  Because “for years” that was the restriction. That doesn’t sound like much of a restriction. The implication is that it’s restricted less now. The story talked about how San Francisco resisted high rises for a long time, so that restriction doesn’t follow the story — that’s why I think it’s a typo.
- Zarel 9y ago
  Yes, which is way higher than I'd expect, given SF's general opposition to high-rises. According to Google, the actual limit is 40 feet. Example article I found: https://recklesslyoptimistic.com/san-franciscos-height-restrictions-and-the-city-s-dark-future-c7796fafb07c https://recklesslyoptimistic.com/san-franciscos-height-restr...
  - jandrese 9y ago
    Yeah, if the limit were 500 feet you wouldn't have builders constantly complaining about it.
  - darkerside 9y ago
    Here's another article cutting a height restriction near 500 feet. http://www.structuremag.org/?p=11635 http://www.structuremag.org/?p=11635 There are probably more height restrictions in different areas, and a 500 foot limit is actually quite restrictive. It would have prevented Salesforce Tower. The Empire State Building is over 100 floors.

Tistel 9y ago

Great/Scary article. Has anyone worked in the tilting building? Are there cracks in the walls? Is the soil compaction expected to stop (some max density type thing)? I think they stopped the tower of Pisa tilting by injecting concrete under it. It must be difficult to not exasperate they problem at the start of the injection (I am guessing they have to remove some material first).

whafro 9y ago
I knew someone who lived in the building, and while she didn't report cracks in the walls, she did say that things would reliably roll toward one corner of her apartment if they weren't secured.
- tlb 9y ago
  14 inches over 58 stories works out to 0.10 degrees. That doesn't seem like enough to make anything roll. You might have to shim your billiard table.
  - kowdermeister 9y ago
    A golf ball sounds like something to me: https://www.youtube.com/watch?v=dCUCa0Bvh1k https://www.youtube.com/watch?v=dCUCa0Bvh1k
  - saalweachter 9y ago
    Your floor being on a 0.1 degree slope is a rise of 0.2 inches over 10 feet. Definitely noticeable.
    - jessriedel 9y ago
      Not definitely. The professional standard for levelness in homes and office buildings is F_L ~ 20, where F_L is the levelness "F number". http://www.concretefloors.ca/?page_id=546 http://www.concretefloors.ca/?page_id=546 http://www.betagroupgc.com/Concrete%20International%20-%20The%20Floor%20Flatness%20Report.pdf http://www.betagroupgc.com/Concrete%20International%20-%20Th... The maximum slope b=rise/run compatible with this is b_max = (314 mm/3m)/F_L = .105/F_L ~ 0.005 for F_L = 20, https://www.astmfree.com/wp-content/uploads/2018/01/E-115-M.pdf https://www.astmfree.com/wp-content/uploads/2018/01/E-115-M.... which corresponds to 0.005 radians = 0.3 degrees. Projects like roller rinks and warehouses that use air pallets require more level floors, but typically only by a factor of 2 .

nextstep 9y ago

Reason no. 42614 not to live in the San Francisco Bay Area.

collyw 9y ago
42615, you might end up working with Salesforce.
- andegre 9y ago
  I'm chiming in late in the game here, but what's wrong with Salesforce? (Only reason I ask is because of the piece that I just saw on 60 minutes Sunday night, so your comment piqued my interest)
  - PunchTornado 9y ago
    It's slow AF.
    - notfromhere 9y ago
      Basically ever database SaaS tool is slow AF. They don't tell you that during the sales cycle though
    - aidenn0 9y ago
      AF?
      - komali2 9y ago
        as fuck
  - collyw 9y ago
    Development in a web browser. Everything is paginated. A bastardiation of Java and SQL - without joins as the language it uses. An over complicated data model (for the business I had to integrate it with at least. Some things could only be done via SOAP. I had to integrate our existing Django based system with Salesforce. What I expected to take a few days took a few months. Similar syncing of data between another Django based system did take a couple of days. I can't go on, it brings back too many bad memories. If you have ever enjoyed development you will hate Salesforce. It feels like the tech equivalent of digging holes and filling them back in again.

lmilcin 9y ago

It seems shockingly irresponsible that it is allowed to build high rises in areas that can undergo liquefaction. No matter how strong the building is if the ground gives up it must fall over.

Spooky23 9y ago
Blame zoning! Shockingly, the people who own property less likely to collapse in an earthquake do not want big buildings next door. So big buildings are being built on harbor fill. What could go wrong?
elgenie 9y ago
IIRC the proper way to handle that is by anchoring the foundation of the building to the bedrock underneath the layers which can undergo liquefaction. That's done by means of drilling as deep as necessary to put the foundation and then adding pylons on which the building rests. Depending on how deep the liquefaction-prone layers go, that's could be an option that's realistic only for a high rise.
- lmilcin 9y ago
  And how does that relate to Millennium tower which has already "sunk a foot and a half"? What if high rise building is anchored through all liquefaction-prone layers but the layers start to shift (they are on slight incline) when they get liquified? I am not expert but I can imagine it is possible that, if the structural support is long enough, just few inches of lateral movement may completely compromise the support.
  - stale2002 9y ago
    Because the millennium tower did NOT do the correct thing, and did not anchor it to bedrock. They would be having problems if they did it the right way.
- ummonk 9y ago
  Or you can design the building to float on the liquified soil. Either way works.

danielvf 9y ago

This got me wondering what the Salesforce tower’s builders countermeasures were for the soil and seismic issues. Surely they tried to do something. Here’s an article about what they did. (Skip the fluff in first third, it does get down to details later.) http://www.structuremag.org/?p=11635 http://www.structuremag.org/?p=11635

smoyer 9y ago
From the diagrams included in that link, it looks like there's going to be a real problem if "the big one" happens during severe gusting winds.
- onion2k 9y ago
  Even if that isn't the case, the Millennium Tower is literally across the road[1] and could fall in the wrong direction considering "Millennium Tower has sunk almost a foot and a half and is leaning 14 inches toward neighboring high rises" [1] https://www.google.co.uk/maps/place/Millennium+Tower+San+Francisco/@37.7875068,-122.3972696,529a,35y,39.33t/data=!3m1!1e3!4m5!3m4!1s0x0:0x9fe15ebd4a8300d8!8m2!3d37.7905055!4d-122.3962516 https://www.google.co.uk/maps/place/Millennium+Tower+San+Fra...
  - jandrese 9y ago
    Is 14" of lean a lot on a high rise? Certainly that is a small fraction of a degree of total lean. The sinking does seem like a concern and is no doubt related. It seems like someone underestimated how much foundation work would be needed on that building. How does the front door work? Do they have steps down into the lobby now?
  - matte_black 9y ago
    How many inches of lean can a building support before it just falls over WTC style?
    - IAmEveryone 9y ago

cwal37 9y ago

"Right now the code says a structure must be engineered to have a 90 percent chance of avoiding total collapse. But many experts believe that is not enough. “Ten percent of buildings will collapse,” said Lucy Jones, the former leader of natural hazards research at the United States Geological Survey who is leading a campaign to make building codes in California stronger. “I don’t understand why that’s acceptable.”" One way that reads to me is that an event over some threshold has a high probability to cause the complete collapse all of those buildings. 90% doesn't seem like a very high threshold either, if it corresponds straight out to a 1-in-10 event that seems quite bad. If it's a 90% chance of survival in a 1-in-100 event, that's better, but not great.

jerf 9y ago
I suspect it would be the latter, similar to other disaster planning. This gets you into that domain where most people really don't like to go, but... you don't get the choice of 100% perfectly likely to stand up, so where do you draw the line? You don't have an alternative. A line will be drawn. If you don't draw one deliberately, you'll draw one accidentally. But if you want to have some fun with ways the probability estimates could be badly broken, correlated failures can be the way to go. Suppose for the sake of argument that there is an earthquake in the future that if each building was subjected to it individually would cause 10% of the buildings to come down. That doesn't mean that 10% of the buildings will fall down in real life, though, because the failures could be correlated and coupled, if one building falling down makes another building falling down more likely. If I'm running the physics and numbers in my head correctly [1], even in an extremely large earthquake the Hollywood image of buildings toppling each other like dominos is still exceedingly unlikely. They'll go down, not sideways. But the additional shocks they create in both the air and the ground in the process could tip some other buildings over the edge. We know from 9/11 that buildings going down can seriously damage other nearby buildings. So, densely packing buildings with a 90% survival rate can result in a net survival rate less than 90%. And of course, if it's 90% at Richter x, there's no law of the universe that says x is the limit. x+1.5 is still perfectly possible. [1]: It's hard to google up the amplitude of an earthquake in a distance measure, rather than Richter scale or something. But it looks like "several centimeters" of transverse motion would be a very large earthquake, which isn't going to put the center of mass of a building out of the area described by its foundations. Which isn't anywhere near a complete description of what it would take to tip a building like a domino, but is enough to say it's a long way from happening. (My guess is that it's actually impossible to tip a tall building like a domino as any possible attempt to exert the forces necessary to do so would itself be enough to destroy the building. See also "why Superman must also be telekinetic", because it doesn't matter how strong you make an 747, there is no place on that plane it can be picked up by any amount of pressure exerted by two human-sized hands without the hands tearing right through the plane, rather than nicely carrying it. (A handful of non-telekinetic Supermans could do it if the plane lowers the landing gear and Supermans support the tires with their backs instead, but that'll be tricky to "fly" in other ways. Especially since the best way to support the plane will be with the Supermans being sideways, to maximize area of contact with the tire.) Similarly, some sort of Superman-esque force that applies equally to all atoms would be required, rather than the real forces we can apply via external pressures.)

0xcafecafe 9y ago

Of all the natural disasters, I seem to shudder at earthquakes the most. May be because I am biased by witnessing the destruction brought by the 2001 earthquake in India. The thought that at any moment, without warning, the safe abode you are in might come crashing down on you is pretty scary. I wonder with human population increasing and with the shortage of urban land needing highrises, what is the long term solution to this.

f_allwein 9y ago
The long term solution would be having enough energy to modify the earth enough in order to prevent earthquakes. From http://mkaku.org/home/articles/the-physics-of-extraterrestrial-civilizations/ http://mkaku.org/home/articles/the-physics-of-extraterrestri... : "For example, a Type I civilization is a truly planetary one, which has mastered most forms of planetary energy. Their energy output may be on the order of thousands to millions of times our current planetary output. Mark Twain once said, ”Everyone complains about the weather, but no one does anything about it.“ This may change with a Type I civilization, which has enough energy to modify the weather. They also have enough energy to alter the course of earthquakes, volcanoes, and build cities on their oceans."
- adrianN 9y ago
  It seems a lot easier to build floating cities than to cool Earth's core enough to stop earthquakes.
  - jacquesm 9y ago
    That would be a very stupid thing to do because it would also stop the Earth magnetic field which helps to shield us from cosmic radiation.
    - adrianN 9y ago
      When we have the technology to cool Earths core(!), we'll also be able to make our own magnetic field.

chiph 9y ago

> The goal of the code, say proponents of a stronger one, should be the survival of cities — strengthening water systems, electrical grids and cellular networks — not just individual buildings. I'm not sure how you'd prevent water & sewer lines from breaking during an earthquake - they're surrounded by earth (or secured along concrete walls in buried vaults) so they're going to get motion & shear all along their length - so not much room to flex. Assuming they were made of a flexible material and not cast iron. One of the reasons why the 1906 earthquake was so devastating were the fires afterwards, where the fire companies couldn't get water.

ceejayoz 9y ago
After the 1906 earthquake, SF started adding large, distributed cisterns to store water throughout the city. I'd imagine there are lots of similar sorts of tweaks you could make - more a focus on a distributed, resilient grid than preventing pipe breaks entirely.
- komali2 9y ago
  Even in 1989 they couldn't get water, they had to suck it out of the bay.
  - ceejayoz 9y ago
    That appears to be part of the water supply plan (makes a lot of sense to use the water they've got there), and the cistern system appears to have partially functioned: http://www.sfmuseum.net/quake/revawss.html http://www.sfmuseum.net/quake/revawss.html > The upper zone of the AWSS, however, functioned normally through the earthquake period, and was used to suppress earthquake-caused fires. Looks like they're building more: http://abc7news.com/news/over-30-cisterns-to-be-built-in-sf-to-prepare-for-earthquake/68515/ http://abc7news.com/news/over-30-cisterns-to-be-built-in-sf-...

mabbo 9y ago

There are always ways to build the tall buildings safely- they're just more expensive. These buildings aren't unsafe because there's no choice, they're unsafe because the builders wanted to save money and the building code was too loose to stop them. Japan is a highly volitile region, tectonically speaking, yet they've managed to build lots of tall buildings safely. How? By having some of the strictest building codes in the world, yet allowing development within those rules. Meanwhile, outside of SF itself, the Bay area refuses to build any real density that's desperately needed, using earthquakes as (one of many) excuses for NIMBYism and entrenched interests of landlords.

kakwa_ 9y ago
Also, If I recall correctly, what did the most damages in the 1906 SF earthquake was not the actual earthquake itself. What caused the most damages was the fires after the earthquake. Hopefully SF has a better fire department now than in 1906.
- ekianjo 9y ago
  same thing for Kobe in 1995. Fires were responsible for most of the deaths.
- cobbzilla 9y ago
  It's not just the fire department that's better - in 1906 a lot of those fires were caused when the quake would pull a gas appliance from a wall and leave a gas leak that later ignited. Nowadays everyone has their hot water heater and oven bolted or strapped to the wall. I'm sure there are other useful fire codes California has adopted since then but this one rule will probably prevent more fires in the next big quake than any other.
  - JshWright 9y ago
    Additionally, gas fittings that are designed to (safely) breakaway are more common.
  - mturmon 9y ago

deleted 9y ago

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JackFr 9y ago

Weird that the word "Japan" occurs 0 times in an article about skyscrapers and earthquakes. I realize the focus of the article is SF, but when the author elaborates on our lack of experience with skyscrapers in earthquakes, with no mention at all of Japan, it makes me think that this is just a clueless scare piece rather than any kind of thoughtful analysis.

lev99 9y ago
I'm sure the New York Times has a vested interest in keeping New York the economic powerhouse of the United States and this article directly attacks San Fransisco's best option for economic growth. There are entire careers dedicated to determine buildings ability to survive natural disasters and informing people about the risk. There are entire careers dedicated to finding ways to make buildings more earth quake resistant. It seems like banks, developers, governments, and insurance companies would be listening to both of these professionals very closely before building something one thousand feet high. I would prefer to hear from them than Thomas Fuller of the New York Times.
vincvinc 9y ago
Funny, earlier today I just happened to see this Tokyo earthquake footage of skyscrapers swaying violently: https://www.youtube.com/watch?v=ACKMPD6MySs https://www.youtube.com/watch?v=ACKMPD6MySs Then, in the article, I read about San Fransisco: "the issue of seismic safety of high rises was “never a factor” in the redevelopment plans" I can not imagine any positive outcome here.
- sdrothrock 9y ago
  > Funny, earlier today I just happened to see this Tokyo earthquake footage of skyscrapers swaying violently It's unclear from your comment, so I wanted to clarify for other people who may not know: skyscrapers are intentionally built such that they sway, as that helps to disperse the energy more than a rigid structure. http://www.businessinsider.com/earthquake-resistant-buildings-2011-3#the-e-defense-table-is-a-shifting-base-intended-to-simulate-an-earthquake-7 http://www.businessinsider.com/earthquake-resistant-building... https://earlywarninglabs.com/old/ewl/skyscraper-safety/ https://earlywarninglabs.com/old/ewl/skyscraper-safety/

komali2 9y ago

Those of you actually living / working in the Bay Area, I highly recommend looking into "NERT" - Neighborhood Emergency Response Team[1]. It's about 18 hours of training on disaster preparedness, earthquake safety, triage, and search and rescue. The idea is twofold - the more citizens that can handle themselves and their families for the first 72 hours of a disaster, the more people that have a 72 hour timeline to death (trapped, injured) the professionals can find and rescue. The second is that there is literally no city in the world that has the fire department resources to handle a catastrophic disaster (>8 earthquake, tsunami) without "significant loss," and so trained volunteers can do a great deal to "fill the gap." In the 1989 earthquake untrained volunteers were critical in helping the SFFD get water into hoses [2] when the mains went down. Last count I heard is that there's about 2,000 NERTs now trained in the city. Imagine having 2,000 basic-trained volunteers helping out in a disaster. Incredible. To put it in perspective, there's only about 1,500 employees of the SFFD. There's a city-wide drill this weekend, actually, and they need victim volunteers. If you want to get painted with gruesome injuries and scream at people in green hardhats, it could make for a great time! [4] If you aren't in the bay area, check out the FEMA equivalent, "CERT." [3] [1] http://sf-fire.org/neighborhood-emergency-response-team-nert http://sf-fire.org/neighborhood-emergency-response-team-nert [2] http://cdn.abclocal.go.com/content/kgo/images/cms/349779_1280x720.jpg http://cdn.abclocal.go.com/content/kgo/images/cms/349779_128... [3] https://www.ready.gov/community-emergency-response-team https://www.ready.gov/community-emergency-response-team [4] https://www.eventbrite.com/e/victims-needed-volunteer-for-the-nert-citywide-drill-tickets-44821250567 https://www.eventbrite.com/e/victims-needed-volunteer-for-th... edit- by the way, this training is free, and comes at no obligation to actually run into burning buildings should a disaster happen (they want you to take care of your home, family, and neighbors before anything else)

songzme 9y ago

Apparently South Michigan is the safest place to live from natural disasters: https://www.quora.com/What-is-the-safest-place-to-live-in-the-USA-that-is-least-likely-to-be-effected-by-earthquakes-tsunamis-volcanic-eruptions-or-similar-events#!n=12 https://www.quora.com/What-is-the-safest-place-to-live-in-th...

anothergoogler 9y ago
That's just a random Quora user's opinion. Southern MI sees plenty of powerful tornados. For instance https://en.wikipedia.org/wiki/1980_Kalamazoo_tornado https://en.wikipedia.org/wiki/1980_Kalamazoo_tornado and https://www.weather.gov/grr/1965PalmSundayTornado https://www.weather.gov/grr/1965PalmSundayTornado
zer00eyz 9y ago
I know what your saying but all I could think of was Flint.
_jn 9y ago
IIRC, Las Vegas is also pretty high on that list, hence the data centers.

jasondc 9y ago

I thought the massive water tank at the top of One Rincon Hill , to control swaying in the event of earthquakes, was interesting: https://www.sfgate.com/bayarea/article/One-Rincon-tower-features-water-tank-on-top-to-3299035.php https://www.sfgate.com/bayarea/article/One-Rincon-tower-feat...

ggcdn 9y ago
Straight from the article: > The damper system has no connection with the seismic safety of One Rincon. It is always a challenge to build a tall structure in earthquake country, and One Rincon's engineering response was to use outriggers, tall reinforced concrete columns built around the core of the building.

czep 9y ago

"Witnesses on the morning of April 18, 1906, described the city’s streets as rising and falling like a ribbon carried by the wind." "one out of every four buildings in the Bay Area might not be usable after a magnitude 7 earthquake" "At a time when the average price of a home in San Francisco is above $1.2 million..." Why aren't people pricing in an earthquake discount? This is so totally irrational, housing in SF should be cheaper given the certain risk of an earthquake and consequent large probability of severe damage. And even if your house isn't destroyed, good luck finding a contractor post-earthquake. Even now contractors are so hard to find, over priced, and many do shoddy work, I can't imagine why people don't see this coming and stop paying this much for something that may fall down any day now.

kazinator 9y ago
> Why aren't people pricing in an earthquake discount? Because it's a matter of insurance, and thus reduced to a recurring premium bill. Why not price all maintenance costs and electricity too? Living in this house for the next fifty years will cost you all these utility bills; you should get a discount from the purchase price to reflect that! :)
- czep 9y ago
  Few insurers offer earthquake insurance, and those who do charge very hefty premiums, we're talking about adding 50% to the cost of your mortgage over 30 years. Hence, a very small portion of the housing stock in SFBA is insured against quake damage. I still want to know why people aren't thinking about this when they pay so much for a house.
- banachtarski 9y ago
  Lol nobody has earthquake insurance. It's exorbitantly priced.
  - jiveturkey 9y ago
    11% of homeowners have earthquake coverage in CA. http://www.latimes.com/business/la-fi-agenda-earthquake-insurance-20171002-story.html http://www.latimes.com/business/la-fi-agenda-earthquake-insu... Like all insurance, the price reflects the risk vs the number of buyers. If more people had it, the price would be less exorbitant.

jumelles 9y ago

It's not an if, it's a when. You couldn't pay me enough to live in SF.

davidhegarty 9y ago

Love every opportunity to link to this story: http://www.slate.com/blogs/the_eye/2014/04/17/the_citicorp_tower_design_flaw_that_could_have_wiped_out_the_skyscraper.html http://www.slate.com/blogs/the_eye/2014/04/17/the_citicorp_t... The Citigroup building in NYC had a fundamental design flaw that could cause it to collapse.

deleted 9y ago
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bigger_cheese 9y ago
That story is pretty well known in Engineering circles - we used it as an ethics case study at my Australian University.

product50 9y ago

Very one sided article and full of scaremongering. There is no comparison with building codes of other countries which are earthquake prone (such as JP or TW), only example is provided (Millennium Tower) and it is unclear if liquifaction will only affect skyscrapers or 1-2 storey buildings too.

flyGuyOnTheSly 9y ago

>Previous earthquakes have revealed flaws with some skyscrapers. A widely used welding technique was found to rupture during the 1994 Northridge earthquake in Los Angeles. (Many buildings in San Francisco and Los Angeles have not been retrofitted.) That statement really boggles the mind. How do you own some of the most valuable property in the world, and not maintain it in the simplest of ways against something that could literally destroy your investment? After 24 years of knowing that your building was in danger?