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posted by CoolHand on Tuesday May 19 2015, @09:12PM   Printer-friendly
from the space-bridges dept.

To detect stresses and deformations in large structures before they cause damage and deaths, the European Space Agency is working with the UK's University of Nottingham to monitor the movements as they happen using satellite navigation sensors. The team uses highly sensitive satnav receivers that transmit real-time data to detect movements as fine as 1 cm combined with historical Earth observation satellite data. By placing sensors at key locations on the Forth Road Bridge in Scotland, they detected stressed structural members and unexpected deformations

The global market for the installation of GeoSHM on existing and currently planned long-span bridges is worth in excess of $1.5 billion. The UK market alone is estimated to be worth in excess of £200 million and growing. China is expected to be the largest market. While GeoSHM is designed mainly for monitoring bridges with a main span greater than 400 m, it also has potential for shorter bridges, such as Hammersmith Bridge and the Millennium Bridge in the UK. “Eventually, GeoSHM could be deployed for monitoring offshore wind turbines, masts, towers, dams, viaducts and high-rise buildings, for example,” said Xiaolin Meng, GeoSHM team leader.

 
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  • (Score: 2) by c0lo on Tuesday May 19 2015, @10:40PM

    by c0lo (156) Subscriber Badge on Tuesday May 19 2015, @10:40PM (#185236) Journal
    The satellite doesn't "observe" the structures, it's just a beacon transmitting GPS signals. The trick is in the GPS receivers acting as high precision sensors - you have instant displacements without the errors involved by a double integration over time of acceleration. TFA:

    The team fixed highly sensitive satnav receivers for detecting movements as small as 1 cm at key locations on the Forth Road Bridge in Scotland.

    The "drawback" in GPS sensing that I'd be worried about: seems that the variations in altitude are tricky to measure with the same degree of precision [gpsinformation.net]

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  • (Score: 2) by frojack on Wednesday May 20 2015, @01:26AM

    by frojack (1554) on Wednesday May 20 2015, @01:26AM (#185269) Journal

    The movements that were NORMAL for this particular bridge were rather large:

    that bridge moved 3.5 m laterally and 1.83 m vertically under a wind speed of 41 m/s.

    Now, 41 m/s of wind is 90+ mph, and you would probably want that bridge closed just to prevent wind induced accidents with big trucks blowing over.

    Unless the bridge is expected to fail slowly, I don't see how this scheme saves much money.
    Bridges often exhibit substantial rust and member-rot before there is a lot of movement or deformation. It might help in that situation.

    But actual failures often give zero warning, because that is how steal fails. The I35 collapse [wikipedia.org] as well as the I5 collapse [wikipedia.org] were very quick.

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    • (Score: 2) by c0lo on Wednesday May 20 2015, @04:06AM

      by c0lo (156) Subscriber Badge on Wednesday May 20 2015, @04:06AM (#185294) Journal

      But actual failures often give zero warning, because that is how steal fails. The I35 collapse as well as the I5 collapse were very quick.

      Interesting. (one of the benefits of cable suspended structures is that, unlike plates/chains, usually a cable doesn't break without warning - maybe not plenty of warning, but some strands will break earlier and would be visible)

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      • (Score: 2) by frojack on Wednesday May 20 2015, @04:31AM

        by frojack (1554) on Wednesday May 20 2015, @04:31AM (#185300) Journal

        Yeah, those are seeming immune to anything but ships and wind.

        But cable bridges seem to get a hell of a lot of maintenance. Golden Gate has a permanent "crew" of something like 100 guys.
        The paint crew alone is some 35 people.

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    • (Score: 2) by soylentsandor on Thursday May 21 2015, @05:19AM

      by soylentsandor (309) on Thursday May 21 2015, @05:19AM (#185899)

      Your link to the I5 collapse links to the I35 collapse. It should link to this [wikipedia.org].