grand canyon skywalk - pretty cool...eh1

huangyhg

grand canyon skywalk - pretty cool...eh!
4000 ft drop
pretty nifty- looks like they're well underway with it.
where is the sky hook?
71,000,000 pounds?!? are they sure they didn't miss a decimal point somewhere?  i'd like to see an engineering article on how that thing withstands that much load.
the 71,000,000lbs includes all the seagull crap.....
that would be scary to walk on.  i went to calgary tower and i got pretty scared walking on the glass floor.
how many seagulls ar there in the grand canyon ?
really lost and tired ones, i expect ??
there are a couple of old threads on this structure.
don't know about the grand canyon specifically.  but in the bird books, they're not "sea gulls", they're "gulls", and they were pretty common in colorado.
71 million pounds?!  does anybody know what those beams are, or if that load is a major typo?
i did a quick calc because i'm bored at lunch:  assuming from those photos that the beams are 3ft x 6ft solid 50ksi steel, not dealing with self weight at all, and assuming the load is uniformly distributed, i get a max cantilever of about 10ft.  
maybe they only allow 1 tourist at a time lol.
that would be one fat tourist!
i was commenting on pmr's calc of max cantilever of 10 ft.  i still cant find where the 71 million lbs literature.
"enabling it to withstand the weight of 71 fully loaded boeing 747 airplane",  i doubt a boeing 747 can fly with 1 million lb total weight.
according to one website, a 747-200f has a max takeoff weight of 833000#.  of course i don't see where they are going to park 71 747's on that bridge and still have room for one fat tourist!
gotta work now
the fat tourist would also have to lay down to uniformally distribute his weight. even less room for plane parking.
foets
"social drinker with a golfing problem"
if you click on the video on the website listed at the top, you get a little bit of a feel of what the structure is like.  the beams are 32" x 72" twin steel box beams in a horseshoe shape.  the glass floor is 5 "plies" thick - 3 19 mm plies, an 8 mm ply, and a 6 mm ply.
they did actual wind speed collection at the top of the cliff and recorded speeds of 80 and 90 mph.
the video also talks about 71,000,000 pounds.  i'm still not quite sure where they get that number, because according to that video the glass floor is good for a little more 100 psf.  that would mean a walkway area of 710,000 square feet to get to 71,000,000 pounds.  there is no way the structure itself could hold up that much weight.
maybe the 71,000,000 is the theoretical load the foundation could withstand.  the structure would fail long before you ever got to that load.
so, assuming you want to go out on it:
do you wait a while to see how it does with people on it, or go right away before it has a chance to fatigue?
one of the earlier threads seem to indicate that the skywalk was built on land controlled by a sovereign nation.  that would raise the question of what code was it required to meet and under what code was it actually designed.
if i went it would be before it had a chance to fatigue.
a couple of interesting things.  they do mention the 71,000,000 lbs in the video.  also, i notice that architects sketch shows beams about 24" deep- compared to 72" for the finished design- a minor change!  lastly- the guy in the video mentions the limestone there is adequate for 16,000+ psi- is that reasonable, or is he confusing psi with psf (he interprets it that the limestone is 4x stronger than concrete).
on wikipedia, i found a quote (no source given) that states:
"the skywalk will be able to hold 70 tons of weight, allowing for 800 people weighing 175 lbs. each to stand on the bridge. "
elsewhere on one of the official sites, i find a statement thus:  "on may 2005, the final test was conducted and the stucture passed engineering requirements by 400 percent, enabling it to withstand the weight of 71 fully loaded boeing 747 airplanes (more that 71 million pounds). the bridge will be able to sustain winds in excess of 100 miles per hour from 8 different directions, as well as an 8.0 magnitude earthquake within 50 miles. more than one million pounds of steel will go into the construction of the grand canyon skywalk."
this sounds like the 71,000,000 lbs is perhaps the ultimate strength of the foundation support points or something of the sort- but very different from any load proposed on the structure itself.  this "load test" was prior to any actual steel construction being done, evidently.
16000 is correct i bet.  the 4000 psi concrete we use does go up pretty high after a few months.
here it mentions the worlds largest bolt???.
here dsi doesn't show anything like "the dywidag" mentioned in the picture caption shown in the above. might be holding off until the sky walk proves out.
it would be interesting to know how many the bolts are used and how long they are.

i suspect they mean the "world's largest dywidag bolt".
some material here on the dampers:
from this paperl
"scheduled to open in october 2006,  the skywalk designed by lochsa engineering in las vegas is cantilevered atop the cliff with 94 steel rods that bore 46 feet into the limestone rock. it can support l70 tons of weight, equivalent to 700 big men, but its maximum occupancy is set at 120 people. three oscillating steel plates weighing 3,200 pounds that are inside the hollow bridge beams act as shock absorbers. they move up and down to neutralize the vibrations from foot traffic and vertical wind gusts that may be up to 94 miles per hour. the sides are made from strengthened, three-inch thick, five-foot-tall glass walls."  
somewhere, i saw 2.5" bolts mentioned.  with 94 bolts 2.5" diameter, 71,000,000 lbs gives a stress of 154,000 psi, which seems inordinately high.
i think they should hold a worldwide lottery to see who will be the first base jumper to sail off into the sunset.
in the video, they mention 108 drilled holes
and i assume that means 54 per side and that
is how many bolts are going to be used.  
i cannot comprehend why they would not use some
angular support from the bottom.
i agree that this is an amazing project!
  
i'll volunteer to be the second person to walk out there - let the first person go to make sure it holds up statically and let everybody else after me make sure its fatigue properties are ok...
i saw this a few months ago and threw out the 71 million pound load as garbage.  i agree with previous posters about that number migrating over from the foundation side of things.  what may have happened is that the square area of the compressive portion of the foundation, coupled with the compressive strength of the rock was leaked.  i figure 71 million pounds at 16,000 psi gives a little over 15 square feet per side of compressive area for those beams, which is reasonable.
foets,
how did you capture the picture and post it
to the web?  that is impressive.
dimjim
foets
"social drinker with a golfing problem"
an update on the project here.  still sounds optimistic- like they'll be marching people out there just as soon as they get it slid out into place.
are they going to make people put on booties when they walk out there, or is it quickly going to get as scuffed as the glass floor in the cn tower?  ($25 oughta include a pair of paper booties.)
hg
i saw somewhere on that site where they mentioned booties, so i think that is a part of the plan.
i'd tend to go with the leaning walls as in the gateway arch rather than a glass floor, but it's a done deal.
why not put a film that can be replaced a lot cheaper every a few months?
nice to see they are going to send out the media and a few politicians first.
i think they should hang a 747 on the tip of the bridge lol.
this thing is now opened. for $25.00 you can walk out on it and scare yourself to death.
i can't even watch while indy jumps across that invisible bridge in the holy grail movie...you aren't going to see me out on that any time soon.  
if it is open, how come i couldnt fint any pictures when i googled it?
the official website says that it opens on mar 27. see fp for the website.
i'll get it right one day.
it was officially dedicated today will all the locals and eugene cernan walking out and shaking hands at the tip. while i was watching i didn't see and cameras pointing down.  
hadn't got it right yet. the astronaut was buz aldrin.
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pretty nifty- looks like they're well underway with it.
where is the sky hook?
71,000,000 pounds?!? are they sure they didn't miss a decimal point somewhere?  i'd like to see an engineering article on how that thing withstands that much load.
the 71,000,000lbs includes all the seagull crap.....
that would be scary to walk on.  i went to calgary tower and i got pretty scared walking on the glass floor.
how many seagulls ar there in the grand canyon ?
really lost and tired ones, i expect ??
there are a couple of old threads on this structure.
don't know about the grand canyon specifically.  but in the bird books, they're not "sea gulls", they're "gulls", and they were pretty common in colorado.
71 million pounds?!  does anybody know what those beams are, or if that load is a major typo?
i did a quick calc because i'm bored at lunch:  assuming from those photos that the beams are 3ft x 6ft solid 50ksi steel, not dealing with self weight at all, and assuming the load is uniformly distributed, i get a max cantilever of about 10ft.  
maybe they only allow 1 tourist at a time lol.