production rates for hydraulic hammer

[exMKguy]

I'm trying to estimate the time it would take to break up a fairly massive concrete structure having 4'3" thick walls, 30' tall, basically a box with a 185 foot outside perimeter. Concrete is 4000-5000 psi but not reinforced. However, it is encased between 3" thick steel plates on the outer and inner sides and the plates are held together with struts of angle iron. Basically they used the steel plates for the form and poured the concrete between them. The steel plates are welded in about 5' lifts (6 rings). Cutting the steel off before breaking the concrete wouldn't be easy.

I figure I might be able to pulverize the concrete inside the plates, and break the struts off in the process and then muck out the rubble and then cut the plates out on the lift. I would use a 5000# hammer on an excavator that I have. But I'm guessing that it would be a bear to break the concrete inside the steel walls.

Seems maybe more efficient to remove one 5'vert by 10'Horiz steel plate on the inner wall and then break out the concrete around that opening and then remove the next inner plate and so on - (customer really does'nt want me free-falling concrete rubble but.....) constantly breaking towards the outer steel wall.

Or, another thought is to break out a 'pocket' where I removed the inner plate and then working my way back in between the 2 plates and around the perimeter breaking into the intact concrete from the just rubblized concrete. I'm preferring to work between the 2 steel plates and mucking out the rubble periodically since customer prefers that the rubble doesnt "free fall". Any thoughts as to practicality or either approach?

Now the $64,000 (or more) question - any where that I might find a production rate for something close to what I described ( 4'3"wide by 5' deep per layer)? I've not yet used a hammer to break up concrete so don't have a good feel for production. Your ideas and information sure would be appreciated.

Thanks.

 

[Wolf]

Sounds like a fortress, What kinda building is it with walls that thick?

 

[exMKguy]

fortress

Yeah would be a heck of a fort but it's an old nuclear reactor containment structure

 

[tylermckee]

If you cant strip the steel from one side it's going to be a major PITA. What is wrong with rubble free falling? what is around the structure thats so important? 30' isnt all that high. You might want to rent a bigger hammer too. Breaking never goes as quickly as you would hope.

 

[surfer-joe]

Chances are that the containment structure is mildly radioactive, thus the need for keeping falling debris and particularly dust to an absolute minimum. Even cutting the steel could possibly release radioactive particles that could be hazardous to workers health and the general public at large. Doing this job might be like biting a Grizzly Bear in his nether regions. It's not impossible, just difficult, and working with nuclear facilities can involve a lot of regulatory compliance issues that are costly to meet to say the least.

However, if the materials are not radioactive or at least very low level, I'd cut off one side of the steel plating -- starting at the top --with a big air arc or oxygen lance. Then using as large and as new a hydraulic breaker as you can find, bust out the concrete from inside the box. The operators station will need to be protected by a heavy grill to prevent operator injury. I don't think a big hydraulic shear will work as it doesn't sound like it could develop a bite with the steel and concrete being in such close contact.

You may have to have a water spray system in place to hold down the dust. This can lead to all kinds of complications -- if, as I say, the materials are radioactive.

Depending on how old the structure is, the concrete may be hard as hell and hitting it with the hammer may lead to splinters of extremely sharp concrete flying off in all directions. You will want to watch for that, as one sharp piece could slice a workers throat. I know from experience that it splits steel sheet metal open like a hot knife going through butter.

So, a couple of questions, is the shell radioactive? What happens to the debris, how is it to be removed off site? Can it be recycled?

Good Luck!

 

[Countryboy]

Welcome to Heavy Equipment Forums exMKguy! :drinkup

 

[digger242j]

So, a couple of questions, is the shell radioactive? ...

My first thought when I read about the 3" thick steel was of what a good price it might bring at the scrap yard, but now that you mention radioactivity...

I was in the scale house at a scrap yard one day, and the radation alarm went off. It wasn't anything loaded in the pickup truck full of scrap on the scale. It was the guy in the passenger seat, who was a cancer patient, and had some sort of radioactive implant. The lesson here being, that those detectors must be pretty sensitive....

 

[exMKguy]

Update and one way to guess-timate production

Yes, the RAD (radiation) aspect of the concrete debris and dust is a definite issue/consideration. So ifor the steel, too. None of this stuff is going anywhere but to burial at a proper facility. Real shame considering all the steel - Zero salvage value and a big disposal cost.

Anyhow, back to my original question. I got in touch with Indeco, the hammer manufacturer and learned about their Breaker Selection Guide on the web at www.indeco-breakers.com. You can use it to pick a tool/carrier combination for a given production rate (lots of selections for both tools/carrier and for picking a situation that might come close to what you're dealing with) - or - to get a feel for a reasonable production rate given the job's nature/circumstances and your machine.

I dont work for Indeco and have no relationship with them - just thought someone out there might benefit.

p.s. Thanks for all the useful comments and ideas.

Cheers, Jack

 

[Wolf]

Rad

How deep do you have to bury that radioactive debris? What kind of precautions do you have to take when you are demo'ing the structure? Sounds like a pretty unusual job that requires great skill.




:usa

 

[tylermckee]

sounds like a job you need to bid for the absolute worst case senario, or go T&M.