# Sound to destruct/ break concrete

## Main Question or Discussion Point

Would it be possible to break concrete into rubble with sound?

if so, How much energy would it take?

Forgive me if this is a stupid question, Im not a physics guy but am trying to learn.

Joe

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Sound or pressure waves are the wrong sort to disrupt concrete.

The damaging ones are the shear waves a la earthquakes.

Would it be possible to break concrete into rubble with sound?

if so, How much energy would it take?

Forgive me if this is a stupid question, Im not a physics guy but am trying to learn.

Joe
Yes it might be possible using ultrasonic shock waves.
These are not concrete http://en.wikipedia.org/wiki/Lithotriptor though similar.

My thought are if we can make sound crumble concrete we can use this device to rescue people in a a colapsed building. without heavy equipment.

DaveC426913
Gold Member
My thought are if we can make sound crumble concrete we can use this device to rescue people in a a colapsed building. without heavy equipment.
You may have a few conceptul hurdles to overcome.

1] What would happen to the survivors when they are hit with a shock wave powerful enough to shatter concrete?
2] What would happen to the survivors when the concrete is shattered to rubble over their heads?
3] What would happen to the structure - already highly unstable and liable to collapse at any moment - if you start reducing parts of it to rubble?

The purpose of heavy machinery is that it can remove large pieces one-by-one with a minimum of disturbance - and thus danger to the survivors - to the existing unstable pile.

You may have a few conceptul hurdles to overcome.

1] What would happen to the survivors when they are hit with a shock wave powerful enough to shatter concrete?
ok i'll admit we have some hurdles.

2] What would happen to the survivors when the concrete is shattered to rubble over their heads?

my thought, I was one of the people that was in the oakland bridge collapse trying to free people from a very unstable structure. but i noticed then we had to shore up the bridge on top of us, but we some of the tools were to big to get into the small areas. If i could have shored up the area around the victim and had a smaller unit that would blast the concrete off it would seem to be easier and faster ( in a perfect world )
3] What would happen to the structure - already highly unstable and liable to collapse at any moment - if you start reducing parts of it to rubble?

we would still have to shore it up around the traped people, maybe the rubble could be vacumed out with the large 8" hose.

just a thought

forgive the spelling errors

Joe c

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You were one of the rescuers? God Bless you.
Must have been a terrible thing to deal with.

DaveC426913
Gold Member
...I was one of the people that was in the oakland bridge collapse trying to free people from a very unstable structure...
Wow. Were you a rescuer, or one of the luckier victims?

sophiecentaur
Gold Member
To return to the OP, I think there would be a huge problem of Impedance Mismatch between the air / concrete interface (the two media have very different densities). Most of the sound energy would be reflected. It could, however, work better underwater because the density of water is nearer that of concrete. Kidney stones are broken up using ultrasound pulses on this principle. Also, there is a Shrimp which stuns its prey this way (can't remember its name. though).
The Reverend Ian Paisley used to work along the same lines. Fairly successfully, too, on occasions.

It was a long time ago, I was called in to help shore up the lower bridge from falling further. It was sureal. after a few days the spell of rotting flesh was overwelming. I went 5 days without sleep on adrenline ( or the fear that i would be crushed )

anyway sometimes i still see clips of me on with Dan Rather, Peter Jennings, Ted Kopple and the other CNN. I don't know where all those old clips are kept but one of my kids was watching tv and said ..Dad is that you? Its wierd how life puts you in places to test yourself.

So much for the rambling. Thanks for the answers.

Joe C