Erections gone wild

[Sho'Nuff]

Bridge erections, that is. As a fan of megamachines in general I found this mesmerizing.

 

[IronWing]

Daaaaamn!

 

[DrPizza]

That's really cool. I've often wondered why we don't standardize a lot of things that we build things out of here. Each of those sections could be built off-site, and the final bridge assembly would take days, instead of a year or longer to build on-site.

 

[Sho'Nuff]

That's really cool. I've often wondered why we don't standardize a lot of things that we build things out of here. Each of those sections could be built off-site, and the final bridge assembly would take days, instead of a year or longer to build on-site.

I think you could probably standardize some aspects of bridge componets, but due to the variability in install location it is probably very difficult to standardize a lot of them. Then again, the Chinese seem to have at least figured out how to accelerate some parts of the process.

The Chinese have also invented a machine for paver/brick roads. Pretty cool:

https://www.youtube.com/watch?v=GIhttsAM5YQ

 

[EliteRetard]

Is it really worth it, how much time and effort do they save vs just using traditional machines to move and place everything? Even if you wanted to place things from above, why couldn't you just drive a crane across the top and then have it reach over and drop the girder in, without having to do all the weird creeping stuff. In fact you could have the crane up front doing the placement, and a much simpler machine to deliver the girders behind the crane.

Still, that's a really nifty machine.

 

[skyking]

It won't work that way. The crane required to set that section would collapse the bridge.
When we set big girders it is always off the ground and not the bridge for that reason.
That machine is absolutely the bomb!

 

[EliteRetard]

It won't work that way. The crane required to set that section would collapse the bridge.
When we set big girders it is always off the ground and not the bridge for that reason.
That machine is absolutely the bomb!

Are you thinking about the counter weight, or something else? What if the crane used little to no counter weight, and simply "clamped" itself to the previous girder. And a small weight hanging farther out could also counter balance things, no?

Clearly I'm not the expert, which is why I formatted my posts with a question before a hypothesis.

 

[skyking]

I understand. I have experience on bridge jobs and crane work. It takes a massive crane to move a load like that one.
I'd estimate the weight of that hollow box section at 500,000 pounds. It takes a crane weight of 1,200,000 pounds to put it out that far due to the physics.
So you proposed clamping to the beam itself.
Concrete is only loaded in compression. If you load it in tension, it comes apart. That girder has hundreds of cables running through it, that were pulled by hydraulics to put them under tension. The girder was cast and the tension released. Now those cables are holding the structure in compression.
Trying to torque off that structure would blow it up in dramatic fashion.
That machine uses the weight of that beam to reach itself out to the next pier, and then trams it out there. It is elegant as can be, a true marvel.

 

[twinrider1]

....The Chinese have also invented a machine for paver/brick roads. Pretty cool:

https://www.youtube.com/watch?v=GIhttsAM5YQ

I doubt they invented it.

 

[EliteRetard]

I understand. I have experience on bridge jobs and crane work. It takes a massive crane to move a load like that one.
I'd estimate the weight of that hollow box section at 500,000 pounds. It takes a crane weight of 1,200,000 pounds to put it out that far due to the physics.
So you proposed clamping to the beam itself.
Concrete is only loaded in compression. If you load it in tension, it comes apart. That girder has hundreds of cables running through it, that were pulled by hydraulics to put them under tension. The girder was cast and the tension released. Now those cables are holding the structure in compression.
Trying to torque off that structure would blow it up in dramatic fashion.
That machine uses the weight of that beam to reach itself out to the next pier, and then trams it out there. It is elegant as can be, a true marvel.

How about something like this:

 

[skyking]

very nice drawing.
but no, the forces are really out of the realm of imagination. that hook where you hooked it to the girder below would rip that one apart. It would be a great video though!

 

[EliteRetard]

very nice drawing.
*snip*

LOL
That was as fast and crude a drawing as I could make it.

But thank you.

 

[IGBT]

amazing equipment engineering. Wondering why the workers have no safety harnesses on.

 

[EliteRetard]

amazing equipment engineering. Wondering why the workers have no safety harnesses on.

They used them as filler in the concrete.

 

[ImpulsE69]

amazing equipment engineering. Wondering why the workers have no safety harnesses on.

They used all their money building that monster.

 

[TXHokie]

I remember when they built the big high five in north Dallas, they used some erector machine from Italy. I checked out the company and see they got a bunch of similar equipments - http://www.deal.it/equipment.asp.

It worked great as they could built a span overhead and not have to shutdown the highway beneath. Tho every day that I drove by there I always thought that this is the day where they'll have a freak accident and drop one of those cast cement onto traffic below.

 

[JSt0rm]

before we get all impressed with chinese building tech lets not forget...

 

[soulcougher73]

Love this stuff. Thanks for sharing.

 

[Ruptga]

before we get all impressed with chinese building tech lets not forget...

But look how well they built it, it fell over and still didn't come apart! :sneaky:

 

[JSt0rm]

But look how well they built it, it fell over and still didn't come apart! :sneaky:

Can you imagine the horror of moving in next door. D: in the identical building.

 

[lupi]

First I wonder why build that tunnel given how short it is and how little distance from the top it sits.

Second wonder about the type of road construction, a fairly small lane road in what looks otherwise mostly wilderness (transportation wise). Some way of preserving the ground below by having floating roads?

 

[Ruptga]

First I wonder why build that tunnel given how short it is and how little distance from the top it sits.

Second wonder about the type of road construction, a fairly small lane road in what looks otherwise mostly wilderness (transportation wise). Some way of preserving the ground below by having floating roads?

Just guessing, but they could be building over a flood plain.

 

[lupi]

Could be a good guess.

 

[BoomerD]

VERY cool machine, but as mentioned, with Chinese building quality being what it is...what keeps those bridge deck sections from falling off the bridge pylons? (well...besides gravity) Maybe I just didn't see it in the videos, but USUALLY, when pre-cast sections are joined, there are several points to attach them to each other...and often, cables such as the stress cables SkyKing was talking about. (I've seen them build box girder bridges with a silhouette very similar to those from concrete, rebar, and plywood forms. (it's how MOST concrete bridges are built nowadays in the US of A) and when they're done pouring concrete, they run the post-tensioning cables through the bridge from end to end, pull a metric fuck-ton of pressure on them...and the center of the bridge lifts...bends...from several inches to a few feet, depending on design. It's pretty impressive to see.

 

[IronWing]

First I wonder why build that tunnel given how short it is and how little distance from the top it sits.

Second wonder about the type of road construction, a fairly small lane road in what looks otherwise mostly wilderness (transportation wise). Some way of preserving the ground below by having floating roads?

The valley looks intensely farmed so land may be at a premium. Also, is it a road or high speed rail?