screw type pile piers

[astidham]

Hello all,
I spoke with a company that installs screw type pile piers.
I was told these type of piers were being used in new orleans to raise houses above water levels.
The company said they drill them into the ground to bedrock 20 to 30 feet deep sometimes.
would this be a good pier for clay soil? 48" above grade?
i was given an estimate of ~350. per pier installed

[rocking23nf]

looks like a neat idea, but 350$ a pier, wow thats gonna add up.

[astidham]

Im not sure if i can get the height i want for any less, plus I think they would be strong

[JRR]

So, $14000 for 20 piers ... (did I do the math correctly?) ... that sounds pretty good to me.  What is the minimum order?

[dug]

That would actually be $7000 for 20 piers, which doesn't seem too bad for what it is but it seems geared towards applications where the soil is really unstable (eg; former ocean beds/ sand). Just a guess but I can't see another reason for going that deep.

On the plus side, it would probably eliminate any need for bracing.

[astidham]

the price includes a fabricated bracket to hold the beam, also you can have them all installed in a few hours.
i have requested pictures of these piers used to elevate a house, i will post them if they ever send them to me.

[ScottA]

Looks like a cool rip-off to me.

[Don_P]

This is the ICC-ES report for one type;
http://www.icc-es.org/reports/pdf_files/UBC/5110.pdf

I've not seen them for a raised pier, my understanding is that they were developed as a deep piling to pick up soil bearing under a structure at grade like a grade beam or slab. That pipe size looks too small for much free height. It is engineered so ultimately whatever their engineer is willing to accept liability on. There was an article on them in JLC a few years ago. One of their engineers sat at my table at a conference a few years ago, we talked a bit about them during breaks but I doubt I still have any contact info.

That is getting into the price range for a crawlspace. I've been thinking about another way. Starting with something along these lines in the corners would do alot to lock the piers.
A modification of a pier and curtain wall with sonotubes and gravel footings under the curtain wall wouldn't be too difficult. I've got ~1/2 yard in a 8' x3'X6" wall. The gravel could fill to grade with the curtain wall on top.

[astidham]

Thank You Don_P
Here is the company link
http://www.ram-jack.com

[Don_P]

Thanks for the link, I followed it a bit to the design page;
http://www.concretenetwork.com/concrete/foundation_repair/design-helical-piles.pdf
The lateral section is where to pay attention on piers and pilings.

Where deep foundation elements stand unbraced in air, water or fluid soils, it shall be permitted
to consider them laterally supported at a point 5 feet (1542 mm) into stiff soil or 10 feet (3048
mm) into soft soil unless otherwise approved by the building official on the basis of a
geotechnical investigation by a registered design professional.

I found the JLC article on disk from May '04. He's a contractor in Ft Collins, CO and working with the engineer and patent holder of one of the helical screw systems. At that point he had done about a dozen additions and was running $500-800/piling. He had test borings done beforehand for ~$800-1200 and considered it money well spent, he also had an engineer there during placement, his concern was hitting rock and needing a call of whether they were ok or where and how much they could move and try again.

If it came with a stamped design for your individual project, and it looks like it does, I would keep looking at it.

[astidham]

Thank You again Don_P, I have a rep meeting me monday for a copy of my plans and to give me a more accurate estimate.

[glenn kangiser]

I was on a job where we used these in renovating an old building.  The contractor had a break away driver - that clicked when a certain torque was reached.  Height was not consistent and placement was not exact - requiring the final fitup and attachment to be done by welding.  I assume there are several systems out there.