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on a shallow drilled pier say 6' deep, what are the methods/equipments to drill.. 2

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delagina

Structural
Sep 18, 2010
1,008
I know of a mini excavator with auger attachment as the most common.
What if I can't use it because there are pipes all around blocking the pier location.
 
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First thought was a (manual) post hole digger and a couple of days time.
Would one of these work? (From googling "powered auger handheld")
southland-auger-heads-sea438-64_1000_yzoltl.jpg
 
Delagina:
You might make a simple portable system to do the digging/drilling. The hydraulic motor and auger found on the mini excavator, mated with a portable hydraulic power source. The hydraulic motor and auger would be mounted on a small 3-4 leg structural frame which reacted the torque and applied some downward force on the auger. The legs might be pinned or screwed to the ground, or they could be counter weighted by weights that a couple guys could handle. This whole system could also be mounted on the end of any crane boom which could reach over the piping, and work in an almost horiz. position.
 
I don't know who the contractor will be as this has not been issued for bid or construction.
I just want to make sure the drawing does not come back to me with contractor/client saying this can't be done.
Not sure if contractor normally has this portable auger or they will need to buy or rent this which they may not want to do.
 
dhengr,

if I change this to shallow spread footing or combined footing, is this something they can do in the field by manual digging?
 
Delagina:
Manual digging would certainly be possible, with enough men, shovels and 5-gal. buckets to haul the soil away. You said drilled shallow piers, so in either case, the soil has to stand on its own during the process, unless you case the hole, and/or form the footing. You haven’t really defined the whole problem/project or the loads, sizes, etc., so there is much still to be brought into the planning. You also have to be able to get rebar and enough concrete in there in a timely fashion to complete the piers or footings without a hundred cold joints. What I suggested is fairly common equipment, nothing real special, so any contractor who you want working on the job will be able to get his hands on the right equipment, and include it in his costing.
 
just a bunch of shallow drilled pier foundations for pipe support T post.
most are in open area that can easily be accessed by a mini excavator but 2 drilled piers are inside existing pipes where mini excavator may not access.
 
Delagina:
Will the mini excavator truly not fit, or is it that it just can’t drive straight into position? Lift the darn mini excavator in there with a mid-sized all terrain crane. Doing this kind of work, it is hard to imagine one of those wouldn’t be on site. How are they going to lift pipe, valves and the like in there. You could build a small moveable bridge/platform/ramp system which would span a couple pipes and allow the mini excavator to drive into position. I think you can also fit that kind of auger equipment to the front of a mid-size skid steer.
 
If access is really that difficult, consider helical piers advanced with the motor on a mini or regular sized excavator.
 
How large diameter? In the old days our old billboard sign post footings would be dug by hand with spoon and spade shovels. Depending on the soil conditions they would go well below 6' deep. But they were 18" or 2' diameter max so it wasn't too much to excavate.

Heck - I dug a 2' dia x 4.5' deep hole with a post hole digger when I installed my kid's basketball hoop in a couple hours. With the right tools a couple more feet wouldn't have been much trouble.

 
Last year I designed some pipe supports for an existing pipe line with limited access. The pier holes were dug out by vacuum/hydro excavation.
 
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