To re-phrase a question I asked before:
In my back yard, there are some steel bars embedded in concrete, from the foundations of an old out-house. I want to remove the steel, and leave the concrete intact.
I know I can cut off the steel, but I'm interested to know if I could (even theoretically) remove the steel bars intact, while only damaging the a small fraction of the concrete that immediately surrounds the steel.
Intuitively, it would seem that I could shake the bars out. Is this possible? Can anyone recommend any further reading on the subject (online resources preferred).
We'll assume the bars are not connected to any deeper structure.
It seems like a simple problem, but I can't stop thinking about it!
2006-07-18 09:42:51 · 11 answers · asked by Song2 2 in Science & Mathematics ➔ Engineering
Concrete fails in tension like a ceramic. I suspect that you will damage the concrete pretty seriously in order to extract the steel.
If its packed in dirt, then your vibration wont damage as much concrete, but you are still going to hurt it.
Have you thought about liquid nitrogen or some sort of a dry ice/ammonia combination to decrease the diameter of the steel and then twist/pull it out? If you can handle it safely then you can use it to shrink the metal, and have it detach from the concrete. Be sure you know what you are doing before you handle cryogenics.
2006-07-18 09:56:33 · answer #1 · answered by Curly 6 · 0⤊ 2⤋
Ok, get some water based gel and rub it all over the bars. then go get some copper and rub that in gel and Sarene rap the bars and the copper together. Then connect the two dissimilar metals with 2 coated wires then connect those wires to a car battery... positive to the bars, negative to the copper and let it sit for about 2 weeks. The bars will corrode out leaving the copper.
Change the gel every day or rig up something where both the metals can be submersed in water (salt water's the best)
It sounds complicated but it will work
2006-07-18 16:51:53 · answer #2 · answered by brandon 3 · 0⤊ 0⤋
I don't know! However, I would check to see how sound the old concrete is. If it has aged (or was poorly mixed in the first place) it may be weak and it might be possible to pull the bars out if not too lengthy. If the bars are hooked on their ends you may have little luck. Perhaps you can modify a device for pulling bearings or hubs, etc. to grasp the rod and use the mechanical advantage of the puller's threads to exert a powerful force. Good luck.
2006-07-18 16:51:10 · answer #3 · answered by Kes 7 · 0⤊ 0⤋
It might be possible theoretically, but as a practical matter, I would doubt it would work. To get them out, you'd have to vibrate them enough to damage the concrete right next to the bar enough that it turns to dust. Most of that dust will stay in the hole and settle as you vibrate it. Not much will tend to come out.
Take the easy way out - get a smokewrench and cut the bars.
2006-07-18 16:47:03 · answer #4 · answered by Ralfcoder 7 · 0⤊ 0⤋
probably not- not w/o destroying the concrete or materially compromising it's structural integrity. Even if you successfully remove them, you're greatly diminishing the slab's ability to endure lateral stress.
The steel bar probably has ribs on it perpendicular to it's axis (most do) designed to prevent just that. Even if they're smooth, concrete adheres to steel pretty well. Or they could be exposed ends of a wire grid....
Cut em off.
2006-07-18 16:48:14 · answer #5 · answered by pescadoradvisor 2 · 0⤊ 0⤋
It might be possible but if the bars have ANY protrusions then you're out of luck.
And if they're rusted there, that's as good as being welded in place. Sounds to me like it would be easier to cut the metal off and leave a bit there to weld on more metal.
Good luck.
2006-07-18 16:45:57 · answer #6 · answered by Anonymous · 0⤊ 0⤋
You could look into using piezo-electric transducers at sonic or ultrasonic frequencies. That in combination with a steady pull on the bars might just do the trick. It would be fun to try. If you have a spare $1M or so lying around, I'd like to take a crack at it. =)
2006-07-18 23:15:44 · answer #7 · answered by Daniel T 4 · 0⤊ 0⤋
The answer is no:
Most of the time the steel bars you are referring to are in the form of an "L", so that there isn't a chance of them spinning if it were just an "l".
2006-07-18 16:51:10 · answer #8 · answered by Tim 2 · 0⤊ 0⤋
Pneumatic, hammer drill, large one, if the re-bar, is straight, you can hammer drill the re-bar out as if it were a drill bit. The hammering of the drill frees up the re-bar and the reverse drilling pulls the re-bar out.
It works I did it.
2006-07-18 16:48:30 · answer #9 · answered by scuba 2 · 0⤊ 0⤋
Yes . you can hammer on them or more hi-tech use a vibrator.
either way it's a lot of work.
what would be the need for keeping the bars?
2006-07-18 16:48:12 · answer #10 · answered by Robert F 7 · 0⤊ 0⤋