I have been tasked with setting six NGS style monuments that require 4' x 9/16" rods driven to an average depth of 16'-20'.?ÿ In the past I've driven them with a 16# sledge, but I'm older and smarter now.?ÿ What are you gentlemen using to drive these rods??ÿ Electric demolition hammer and a generator?
Something along these lines seem to be the "hot ticket," although prices vary A LOT ($250 to well over a grand).
http://skidril.com/g20merch.htm?gclid=EAIaIQobChMI5t28h6bS2wIViV9-Ch2bRwCUEAQYASABEgL1X_D_BwE
Loyal
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I'm guessing you are using the screw together rods, I will use a fence post driver to get them in till you get major resistance, then cut them off to near grade. The last little bit is with a big hammer. The point of refusal is when my arm refuses to pound anymore. Loyal's gas powered driver looks interesting and it has a shorter cylinder than a manual driver so you can get closer to the ground.?ÿ
I have used gas powered and electric powered jack hammers to drive #7 rebar down to 5 feet. We rented the equipment from a rental store. I think the cup used to put over the rebar is the type used by commercial tent companies to drive their stakes when setting up wedding tents.?ÿ
Gregg
While I have never done the NGS rods myself, to elaborate on GMPLSs comment, for a few years now I have equipped my truck with a Honda 2k gen and a Bosch sds max hammer drill. To drive #5 bar I use a ground rod driver, it's designed for electricians I'm told, can use #6 too if you like.... Last week I drove 41 18inchers for block corners in about 5 hours, saves a ton of strain on my right elbow. I also carry big coring bits to set caps in asphalt/concrete, a spade bit and chisel bit to dig up gravel roads. Cadastral work and hwy row corners make up 100% of what I do, so the tools pay themselves off.
NOS NGS 1 defines refusal as resisting a static force of 250 kg.?ÿ USACE EM 1100-1-1002 defines it as "the depth at which the rod refuses to drive further or until a driving rate of 60 seconds or less per foot is achieved with a power reciprocating rod driver such as a Pionjar Model 120 or similar device with equivalent driving force of 26.9 foot-pounds/blow and an average of 2,500 blows per minute."
I use a 60-lb. electric jackhammer for the purpose.?ÿ After renting one a couple of times I figured I'd save money by buying one, so I got a Bosch Brute.?ÿ I don't use it often, but when I do it's nice not to have to hassle with the rental thing, and it has long since paid for itself.
Pedantically speaking, there are some problems with those definitions, although you can figure out what they meant.
250 kg is a mass, not a "force".?ÿ They must mean the force (weight) of a 250 kg mass being pulled down by one g gravity.
They must mean "one foot or less per 60 seconds"?ÿ and not the way stated.
Foot-pounds is not a "force", but the energy of the impact.
We use an electric jackhammer and generator. Has worked well so far.
We have a Pionjar, it works great but it spits oil all over the place. It's old; if I was getting something now I'd go electric.
We have a Pionjar, it works great but it spits oil all over the place. It's old; if I was getting something now I'd go electric.
My wife says, ...
Don't screw around.?ÿ Just get the jackhammer driving adaptor from the same place you buy your rods.?ÿ Rent an electric jackhammer and go at it.?ÿ I highly recommend a 3-side scaffold to make you life and back easier.
Something along these lines seem to be the "hot ticket," although prices vary A LOT ($250 to well over a grand).
http://skidril.com/g20merch.htm?gclid=EAIaIQobChMI5t28h6bS2wIViV9-Ch2bRwCUEAQYASABEgL1X_D_BwE
Loyal
?ÿ
I have a Skidril I use on the farm for tee posts.?ÿ Cost $1350.?ÿ You'd need to get the right adapter, maybe have it made special.
I highly recommend a 3-side scaffold to make you life and back easier.
A pickup tailgate works well, as long as you can drive up to the hole.?ÿ I've used a pair of foldable sawhorses bridged by a piece of plywood for sites we couldn't reach with the truck, but that arrangement is a little sketchy and definitely not OSHA-compliant.
(But neither is the activity in the photo above:?ÿ no hardhats, no vests, a guy wearing sneakers holding onto the business end of the jackhammer.?ÿ Not that I haven't been guilty of all that except the sneakers...)
