Forgot your password?
typodupeerror
Supercomputing Science

Shaking a 275-ton Building 110

Posted by Zonk
from the without-using-your-superpowers dept.
Roland Piquepaille writes "If you want to predict how a tall building can resist to an earthquake, some researchers have better tools than others. Engineers from the San Diego Supercomputer Center (SDSC) have built a full-size 275-ton building and really shaken it to obtain earthshaking images. The building was equipped with some 600 sensors and filmed as the shake table simulated the 1994 Northridge earthquake in Los Angeles, California. It gave so much data to the engineers to analyze that they needed a supercomputer to help them. Now they hope their study will yield to better structure performance for future buildings in case of earthquakes."
This discussion has been archived. No new comments can be posted.

Shaking a 275-ton Building

Comments Filter:
  • by MichaelSmith (789609) on Saturday April 14, 2007 @01:16AM (#18728753) Homepage Journal

    The page you are looking for has moved. Please go to the main EurekAlert! homepage to locate the section you are interested in and reset your bookmarks.

    If you are looking for this week's current news releases, click on "Breaking News" once you reach the main EurekAlert! homepage. If you are a reporter looking for the embargoed news section, go to the main EurekAlert! homepage, log in with your username and password and then, from the main reporter homepage, click on "Embargoed News." If you are a PIO looking to submit a release, go to the main EurekAlert! homepage, log in with your username and password and then, from the main PIO homepage, click "Submit a Release."

    Thank you. Please contact the webmaster of the refering page to report the bad link. Thank you.
  • Wow (Score:5, Funny)

    by hack slash (1064002) on Saturday April 14, 2007 @01:19AM (#18728759)
    The simulated quake must've been so big it shook the images off the linked page!
  • Are we at the point in history where we can design a building completely inside a computer and simulate the effect earthquakes of various degrees will have on the building?

    Who makes that software?

    How much does it cost?

    • Re: (Score:2, Interesting)

      by Arclight17 (812976)
      I imagine that the software is custom written.
      But it wouldn't surprise me if there were a market for such a thing... Include some other foreseeable disasters (fire, flood, airplane, Michael Jackson...), and sell it to major construction companies in skyscraper or other 'secure' building markets.

      And just for kicks, maybe add an easter egg like sim city, so that you can destroy your buildings with aliens, dragons, etc. :-D
    • by Tomfrh (719891) on Saturday April 14, 2007 @02:04AM (#18728945)
      Are we at the point in history where we can design a building completely inside a computer and simulate the effect earthquakes of various degrees will have on the building?

      Pretty much.

      Who makes that software?

      People like this: http://www.csiberkeley.com/ [csiberkeley.com] http://www.risatech.com/ [risatech.com].

      How much does it cost?

      About $5000.
    • by Moraelin (679338) on Saturday April 14, 2007 @02:43AM (#18729097) Journal
      Technically, yes. The only problem is, any simulation is only as good as the model it uses. E.g., you can also simulate scattering of alpha particles through a foil, but if you based it on the old raising pie atom model, you'd get the awfully wrong results anyway.

      Hence what these guys are doing: a good old fashioned experiment, involving an actual building on a giant table that shakes, reproducing the exact movements recorded in an actual earthquake. That's how you find out if your model and simulation are actually the right ones. If the building behaves like in the assumed models, then all's well, if not, well, someone will have to come up with a better model.

      It might seem that wth, we already know the laws of mechanics well enough, we don't need experiments to test them. The problem is that any model is based on some simplifications, since you just don't have the computing power to even account for all waves, reflections and interferences in a big building with hundreds of joints and thousands of metal bars, pipes, whatever other discontinuities through the walls. So physicists get to decide what are the important parts to simulate, and which should at best be lost in the decimals.

      E.g., if you want to know if a horse floats, you can just as well imagine it to be a sphere or a cube. (As the wisecrack goes, "you know you're an engineering student if you approximate a horse as a sphere, because it makes the math easier.") Actually, wisecrack aside, for that you won't even imagine it to have any shape at all, since shape is irrelevant. It doesn't really matter what exact shape it is, just the mass and the volume. E.g., if you want to know how fast a rocket reaches the moon, you don't need to know the exact shape or colour of the rocket, you can just think it's a point. Etc.

      That's how we solve problems nowadays. We get to decide what is really important, and what can be safely ignored in the model.

      Unfortunately, if you to be really sure that you did the right choices, you have to compare it to what happens in real life. Does your simulation really behave like the real thing in that situation? Or did your approximating the horse as a sphere lead you to a wrong solution like rolling it along the race track to win?

      That's, in a nutshell, what these guys did.
      • Re: (Score:3, Interesting)

        by AJWM (19027)
        E.g., if you want to know how fast a rocket reaches the moon, you don't need to know the exact shape or colour of the rocket

        True enough for moon rockets, but for some simulations -- like projecting whether a given asteroid (1950 DA [nasa.gov] for example), the colour does matter if you're project the orbit to see if it hits Earth in 800 or so years. Over such long time intervals the difference in sunlight pressure (and a couple of related effects) on a light vs dark surface will affect the trajectory.

        The same effects
        • Re: (Score:3, Informative)

          by Moraelin (679338)
          Very much so. Each problem has a different set of details that matter and details which can be safely ignored. And a different need for accuracy.
      • by jimicus (737525)
        It might seem that wth, we already know the laws of mechanics well enough, we don't need experiments to test them.

        I would point out that every major race in the whole of history has been pretty much convinced that they already knew all the important stuff.

        Aristotle, for instance, also argued that you didn't need to do experiments. And look how spectacularly accurate his models of how an object travels through the air are.
      • It might seem that wth, we already know the laws of mechanics well enough, we don't need experiments to test them. The problem is that any model is based on some simplifications, since you just don't have the computing power to even account for all waves, reflections and interferences in a big building with hundreds of joints and thousands of metal bars, pipes, whatever other discontinuities through the walls. So physicists get to decide what are the important parts to simulate, and which should at best be

      • Here's the long version:

        There was a very wealthy gentleman who wanted a scientific method to be able to predict the outcome of any horse race. He asked a geneticist, a statistician and a physicist to look at the problem and promised each a million dollars if they could find a solution.

        After a year of study the gentleman asks the scientists what they have come up with.

        The geneticist says, "Well, we have looked at parentage, gentic composition, hormone levels, musculature and sexual activity of all the

      • by cluckshot (658931) on Saturday April 14, 2007 @04:33PM (#18734551)

        Since my father was one of the team that sent men to the moon. I know a bit more about simulation and testing than the average bird. On Redstone Arsenal (near Huntsville, Alabama) stands a building where they did full mock up shake testing of the Saturn V rocket. I appreciate the intent of people who wish to do full computer simulations. These are getting very good and they delete with the need for many simple tests. Nothing substitutes for the real thing and doing real tests. This was a 37 story rocket they were launching.

        The remark about decimal points is valid. Everyone forgets that the only math that truly exists is integer math. We enjoy using approximations using floating point math but that is all that these are. They are approximations. The list of errors that arises out of these approximations is long. This math only operates well within about 3 decimal places and then it begins to develop progressive errors.

        In Apollo mission computer programming there was a decision made not to attempt over 5 decimal places in navigation and simply to do correction measurement over time. It worked like a charm. It was possible to calculate much more finely but in reality the measurements were not more valuable. Nothing was to be gained by the determination of 11 decimal places that the mission required for accuracy.

        Shaking a 275 ton building will hold as a good approximation for that size range but will not do too well in estimation of a 275,000,000 ton building. It will require actual measuring of such a building. There are many such approximations that come up that people do not consider. For example the velocity of the top of a building is different than the bottom. In really big buildings level and plumb have to bend for the earth. In really big buildings what is the pull of the tide? All sorts of things like that begin to have significant value

    • by goombah99 (560566) on Saturday April 14, 2007 @03:27AM (#18729253)
      Miliken Library at caltech which was an ten story building built before 1980 had a huge eccentric weighted rotor on it's roof which every year the engineering school would Activate and drive the building into resonance. All the book shelves inside were cross braced to withstand the effect. It's still there.
  • by djupedal (584558) on Saturday April 14, 2007 @01:20AM (#18728775)
    Read more... [supercomputingonline.com]

    "Wednesday, Apr 11 @ 13:13 PDT The powerful earthquake struck suddenly, shaking the seven-story building so hard it bent, cracked and swayed in response. But this was no ordinary earthquake. In a groundbreaking series of tests, engineering researchers from UC San Diego's Jacobs School of Engineering jarred a full-size 275-ton building erected on a shake table, duplicating ground motions recorded during the January 17, 1994 Northridge earthquake in Los Angeles, California. To record the impact on the building, the structure was fitted with some 600 sensors and filmed as the shake table simulated the earthquake, yielding a flood of data including stress, strain, and acceleration -- so much information that engineers were having a hard time making sense of it all. That's where visualization experts from the San Diego Supercomputer Center (SDSC) at UC San Diego came in. "
  • by AaxelB (1034884) on Saturday April 14, 2007 @01:21AM (#18728781)
    Link! [eurekalert.org]

    Two little dashes in the url became one superdash!
  • by Anonymous Coward on Saturday April 14, 2007 @01:23AM (#18728791)
    They threw a truly awesome kegger and cranked the amps to 11!
  • by GFree (853379) on Saturday April 14, 2007 @01:24AM (#18728795)

    It gave so much data to the engineers to analyze that they needed a supercomputer to help them


    Why are they using a supercomputer?

    Screw that, let's wait for Earthquakes@home - and hope the name doesn't scare off some people.
  • Shakey (Score:3, Interesting)

    by Tablizer (95088) on Saturday April 14, 2007 @01:31AM (#18728833) Homepage Journal
    The building where I used to work and write bad software every work day used to be owned by a military contractor and was built to withstand a nuclear blast. It is no longer owned by the military contractor, but is still used by non-mil gov't agencies who want communications to remain up after emergencies (floods, fires, quakes, riots, nukes, etc.) They put their servers and communications centers there. I was told that they used to do periodic "shake tests" on it by hooking up huge cranes to each edge and vigorously shaking it for a while. It seems that would be risky because it would weaken it. Even though shaking it in tests might not topple it, it may introduce undetected fractures that may result in problems on the next earthquake or whatnot. Perhaps its infrastructure is purposely built for easy inspection, being what it was originally designed for.
    • Re: (Score:2, Interesting)

      by Anonymous Coward

      What you describe is a good application for eccentric mass vibrators, if you can affix one to the structure. I do appreciate the scale of the shake table these folks built, but sometimes you can't move the structure to your shake table to test it.

      Eccentric mass vibrators are just like the cell phone vibrator (or other things you know of that vibrate) but much larger. And you strap these to the roofs of large buildings, wherever they are.

      This is a crude Wikipedia article on it: http://en.wikipedia.org/ [wikipedia.org]

      • by Tablizer (95088)
        Another interesting way to do structural testing is called snapback testing. A lot like when you played tug-of-war with your friend, but you let go of the rope. So you attach cabling to a structure and force it to be bent by pulling really hard on it. The coupling mechanism allows for rapid de-coupling of the force being applied (i.e., it lets go). The structure snaps back to its original position, and in so doing you can analyze its dynamic behavior under roughly controlled conditions.

        Don't use ACME snapb
      • And you strap these to the roofs of large buildings,

        In the interest of accuracy, shouldn't the shaking force come from the base of the building, not the roof? or possibly the buldings center of gravity?
  • by Bo'Bob'O (95398) on Saturday April 14, 2007 @01:41AM (#18728867)
    A coworker of mine is in the department, and showed me this page: http://visservices.sdsc.edu/projects/nees/article. php [sdsc.edu]

    It has a video of the shake as well as high def video of the simulations themselves. It's pretty damn cool, you can watch the whole building flex and sway about on top of the the shake table, and the waves propagate through the building. (Each colored dot is a GPS sensor, 10 per floor, over 7 floors).
  • Picture LInk (Score:3, Interesting)

    by Pinky3 (22411) on Saturday April 14, 2007 @01:42AM (#18728871) Homepage
    Link [ucsd.edu] to UCSD news release with pictures.
  • Too bad (Score:2, Funny)

    by Anonymous Coward
    It's too bad noone can find a way to protect steel frame buildings from collapsing due to fire...

    Oh. Wait.
    • by QuantumG (50515)
      That's the absolute best kind of conspiracy theory. Make a claim so stupid that no professional engineer would ever bother to come forward and refute it.

      Let me try to make a parrallel to computing, as there's probably more software engineers here than there are structural engineers.

      Say the so called "digital Pearl Harbor" that has been widely speculated about was to happen. Maybe someone hacks into a power plant and shuts down the power to a hospital and a few thousand people die or something. The world
      • by ikekrull (59661)
        The twin towers had as one of their design parameters the ability to resist the impact of aircraft. To say skyscrapers are not designed to resist aircraft impact shows your ignorance, not the original posters.
        • by sp3d2orbit (81173)
          Bill Clinton couldn't get blown without the world finding out.

          Ignorance is thinking the next president could blow up the WTC without anyone finding out.
          • Alone he couldn't find his way to the bathroom. But that's exactly what the Zionazisraeluminatis want you to believe, as they sit in secret manipulating events from their hidden base in Atlantis. In other news, the Jews sank the Titanic.
      • by AJWM (19027)
        Much like all the structural engineers are sitting there, right now, going "yeah, of course if you fly a jet plane into a building it is going to fall down."

        Uh, no, not necessarily. If it were just the jet flying into the building, it would have fallen at the time of impact. They didn't, it was an hour or so later. The fires (from the jet fuel) had to weaken the structural steel first. The Empire State Building survived a hit from an airliner (admittedly not a jet, so lower speed impact) early in its hi
        • Re: (Score:2, Informative)

          by iminplaya (723125)
          ...because there was no fire.

          Correction [about.com]

          FTL: The plane's high-octane fuel exploded, hurtling flames down the side of the building and inside through hallways and stairwells all the way down to the 75th floor.
          • The plane's high-octane fuel exploded, hurtling flames down the side of the building and inside through hallways and stairwells all the way down to the 75th floor.

            There is a LOT of difference between a B-25 hitting the ESB, and a 757 hitting the WTC.
            A B-25 is about the weight of a current F-16. Fully fueled, it carries about 700 gallons. A 757 has a MTOW of 272,500lb, and fully fueled carries 11,000+ gallons of fuel.
            About the same difference as a pickup truck and a semi.

            The ESB is a hard outer shell bui
            • by Deadstick (535032)
              What's more, the B-25 was at the end of its planned flight, probably with no more than a couple of hundred gallons aboard.

              Incidentally, the reference to "high-octane fuel" is pretty dull-witted. Increasing the octane rating of a fuel has essentially no effect on the energy content or the combustion temperature -- it merely lets you run it in a higher-compression engine, which will put more of the energy into the crankshaft and less out the exhaust pipe. High-octane fire, low-octane fire, same difference.

              rj
            • by iminplaya (723125)
              I wasn't trying to compare anything. I simply wanted to correct an honest mistake.
          • by AJWM (19027)
            Okay, thanks for the info. Make that "no significant fire". Yes, it was significant to the individuals immediately involved, of course, but a good part of the burning fuel (not very much, considering the plane was near the end of its flight) went outside the building. The fire was extinguished.

            Other posters have already compared the relative weights and fuel loads of the aircraft. The energy density of "high octane" avgas vs jet fuel is about the same (about 43 MJ/kg), I see more variation between diffe
            • by iminplaya (723125)
              I didn't mean to sound harsh or anything, and I wasn't even comparing the two. I was just hoping to avoid confusion and save a bunch of ranting and raving about off topic details(too late for me...) and turning the thread into a political flame fest. I would also think that aerodynamic forces from a good, stiff breeze are a lot more stressful on a structure than a puny airplane, as was evidenced by both incidents. BUT, since I haven't done the math, I wouldn't know.
      • by scottv67 (731709)
        Buildings are not something you should fly planes into.. they're not designed to keep standing up under that kind of stress.

        It took me about ten seconds with Google to find numerous pages that describe how the Word Trade Center buildings were designed to keep standing up under that kind of stress.

        Statements by Engineers

        Engineers who participated in the design of the World Trade Center have stated, since the attack, that the Towers were designed to withstand jetliner collisions. For example, Leslie R

        • by QuantumG (50515)
          If it was really the case that these buildings shouldn't have fallen down and something like a "controlled demolition" was going on, every structural engineer in the US would be on the phone to the press. There would be a flood of expert opinion saying this was a stunt. There isn't. There's a few crackpots.

          • by scottv67 (731709)
            If it was really the case that these buildings shouldn't have fallen down and something like a "controlled demolition" was going on, every structural engineer in the US would be on the phone to the press. There would be a flood of expert opinion saying this was a stunt. There isn't. There's a few crackpots.

            So are you saying that Leslie Robertson has been lying on-camera about the design of the WTC buildings in interviews conducted after 9/11? Holy cow! Yes, there are some crackpots, indeed.
            • by QuantumG (50515)
              I'm saying it is nonsensical to claim that you can design a building that can withstand a plane crashing into it.. and that a building falling down after a plane crashes into it is a perfectly reasonable thing for a building to do.

              What the conspiracy theorists are claiming is that this isn't reasonable and therefore there must have been secret caches of explosives in the building which were systematically detonated sometime after the planes flew into it.

              I'm also saying that the stupidity of the second claim
              • by scottv67 (731709)
                I'm saying it is nonsensical to claim that you can design a building that can withstand a plane crashing into it.. and that a building falling down after a plane crashes into it is a perfectly reasonable thing for a building to do.

                The WTC buildings were designed to withstand the force of a plane crashing into them. The guy who designed the buildings has said so on-camera. Straight from the horse's mouth. Also, the buildings did withstand the force of the planes that crashed into them on 9/11. The WTC
    • Re: (Score:3, Insightful)

      by AJWM (19027)
      I'm not sure why that got modded funny.

      Think about why the World Trade Center towers collapsed. (Hint: something to do with the effect of sustained high temperature kerosene fire on the strength of structural steel.)
      • Re: (Score:1, Insightful)

        by Anonymous Coward
        Please pull your head out of your ass, and try this post [slashdot.org] for a dose of reality.
        • Are you one of those 9/11 dorks who heckles people on the subway platform claiming that 7WTC was wired with explosives in advance and then demolished on purpose? Yeah, well, by whom? The White House? You think anyone in this administration is competent enough to plan and execute such a conspiracy? By Silverstein? The FDNY? You're a real fucktard.

          BTW, a friend of mine was an IT guy in that building (7 WTC) supervising vast remodeling of several floors, for years up to and including 9/11. If there were explos
  • ...but what about the stroke?

    I really need some sleep.
  • Ok. Enough stories about using three PS3's in a beowulf cluster as a supercomputer.
  • Yawn! The Japanese have had several thousend ton skyscrapers sitting on springs hooked up permanently with sensors, dynamic counter-weights and dampers for decades now...

    • And the Byzantines have built some amazingly earthquake resistent and very large building some 1600 years ago or thereabout. Despite some large earthquakes hiting what we now know as Istambul, their building is still standing. The question is.. was this the result of (educated) guessing or actual knowledge.
    • by sponga (739683)
      There was also a scandal involving a world known Japanese company Apa Group who built two big hotels that were condemned because they did not meet earthquake code regulation; the leading engineer who is also world known was also convicted of not making many residental structures up to earthquake code.

      Japanese have been dealing with earthquakes a lot more seriously especially ever since the massive blow they took with Kobe, Japan. Unfortunately until than the Japanese relied on brute strength in structual en
  • The building is only 275 tons? I am no building engineer, but that seems pretty light weight for a building, doesn't it?
  • by stikves (127823) on Saturday April 14, 2007 @02:44AM (#18729099) Homepage
    There is a list of all the media (including several movies) on their press release site:
    http://visservices.sdsc.edu/projects/nees/article. php [sdsc.edu]

    This includes both real and simulated building captures (and several overlayed ones).
    • Now thats what I'm talking about! "HD" quality video of this building getting shook. Unreal- when it swayed I was just like O_o

      knowwhatimean?

      Thanks for the link
  • Is it Accurate? (Score:1, Interesting)

    by Anonymous Coward
    As any resident of an earthquake prone area will tell you, earthquakes don't only have lateral motion, but vertical motion as well ... Northridge was not exception. It seems like this simulation, and others, only simulate lateral forces. Catastrophic failures can and do happen in structures due to vertical forces (witness the collapse of the freeway in Oakland). Why do these shake tables not simulate vertical motion as well?
    • I'm no engineer, but if horizontally shifting 275 tons with any kind of vivacity is a challenge, vertically shifting it must be a nightmare. Imagine the stress, and then doing the two in parallel...

  • by fname (199759) on Saturday April 14, 2007 @02:53AM (#18729121) Journal
    As reported in every other story, But this was no ordinary earthquake. In a groundbreaking series of tests, engineering researchers from UC San Diego's Jacobs School of Engineering jarred a full-size 275-ton building erected on a shake table, duplicating ground motions recorded during the January 17, 1994 Northridge earthquake in Los Angeles, California. The guys at the supercomputer center played a role, but they didn't build the building or run the test. It was obviously folks from the Structural Engineering department.

    I'll chalk that mistake to sloth, not pride. No doubt, some are envious of the attention the lead guys get, but the greedy bastards deserve it. In their wrath, they shake the building, lusting for its fall and gluttonous for the massive data.
  • Posted as Anonymous coward for obvious reason

    Link corrected [eurekalert.org]
  • I remember reading about how Tesla could calculate the resonant period of a building, then set up a small mechanical oscillator on an I-beam or some such, and make the whole building shake (eventually) via positive feedback.
  • ...put a 275-ton super computer on the shake table to cut out the middlemen.
  • finnish company (http://www.honkatalot.fi/eng/index.html) has sold many log homes/houses to japan. why? earthquakes do not destroy those at all: if the worst happens, you just use few tools, few guys/gals to help you, and in few hours your log house is fixed. (i have no time to explain how, but ask here, and later i will explain how to fix it *fast* after (almost) any kind of EQ.)

A consultant is a person who borrows your watch, tells you what time it is, pockets the watch, and sends you a bill for it.

Working...