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#66186 05/23/06 10:19 PM
Joined: Mar 2004
Posts: 795
B
BigB Offline OP
Member
Been having a tough time lately with ground rods. 4 hours to drive 2 rods last week, then again yesterday. We normally use a 30 lb Bosch demo hammer after first drilling in 2 feet with a rotary hammer. Rented a 60 lb last week, it didn't do any better. Tried a fence post driver, helped on one, bent the other one bad. Tried driving them at an angle, no luck. Any tips? Anyone tried this?: www.condux.com/products/aerial/dddrvr.htm

It costs $250 plus shipping. I am tempted to try it. Sometimes, the demo hammer just goes nowhere but if you can get in some sharp heavy blows it seems to get the rod moving again.

Sixteen feet of hand trenching two feet deep is out of the question without a backhoe or at least a ditch witch.

Joined: Sep 2005
Posts: 202
W
WFO Offline
Member
Is this rock or extremely dry clay or what?

Joined: Dec 2004
Posts: 1,064
D
Member
Had an AHJ approve bending the rod at 2'(90 degrees) and burying it in the ground once.

The terrain was solid rock, not desert, if this helps....

Dnk..

Joined: Jun 2005
Posts: 821
S
Member
Hell, if you get it down a few feet, that's god enough. Just cut it if it doesn't want to go. It's not doing much of anything anyway.


*kidding

Joined: Jul 2004
Posts: 9,772
Likes: 14
G
Member
This is exactly the situation that caused Mr Ufer to design the concrete encased electrode.
I never really thought about it but what if you drilled a hole in the rock and cemented the rod in?


Greg Fretwell
Joined: Jan 2005
Posts: 5,362
Likes: 1
Cat Servant
Member
From your description, it sounds a lot like Reno!

When you just can't get the thing in more than a few feet... and digging is impractical.. then it's time for a second rod. You also drive it as far as you can, making sure to place it at least six feet from the first, and connect the two with your GEC wire.

Joined: May 2006
Posts: 1
K
Junior Member
try using the blunt end instead of the pointed.. I know it sounds silly but it has worked for me on many occasions...

Joined: Oct 2004
Posts: 26
Z
Member
Ask the AHJ for ideas. They see a lot of different ways of doing things in their travels and can be a storehouse of information. From my own experience the Bosch would outperform that slide pounder.

Joined: Mar 2004
Posts: 795
B
BigB Offline OP
Member
"Is this rock or extremely dry clay or what?"

It's usually about 6 inches of sand followed by a layer of Calichi followed by rock and more Calichi. For those of you who don't know what Calichi is, it's a layer of concrete like deposits formed over time from rainwater mixing with alkali, or lime. It settles several inches below the surface and gets thicker as time passes. It is usually very thick at the drip line of a very old house.

"what if you drilled a hole in the rock and cemented the rod in?"

I usually do drill down 2 feet, but where would I find eight foot rotary hammer bits, let alone a hammer that could drive one?

Joined: May 2003
Posts: 2,876
E
e57 Offline
Member
I have used several slide hammers like it, and they do work, however you are going to still have to beat it.... If having problems with a 60# demo/jack hammer, then you have problems it may not solve other than providing another option to do the work. Which when ramping up the tool to the job is not a bad idea.

Either way it sounds rough, a story I know well. Here its a roll of the dice if you're gonna have serpantine bedrock or sand. Sand it will install itself, rock you can beat all day long unless you find a crack. The trick is finding the crack.... And still chance a 1/2' per hour.

On those days when i have to do the pounding, or when nice enough to lend a hand to the lower wage slaves who I have tend this, I often day dream of something like this drilling rig. set up and let rip. http://www.portadrillmini.com/index.php?a=pdmMain

If you know of a freindly fab shop, or own a welder, you may be able to make a lighter duty version to mount a long core drill or extended length hammerdrill to. As for bits, I do know of several siezmic shops that have made thier own for purposes like this, to drive pins and grout. Simular to what this guy makes... http://www.hydratek2000.com/

Sounds like the type of soil your in would be like cementing it in afterwards....


Mark Heller
"Well - I oughta....." -Jackie Gleason
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