Soil Compaction Test?

[apeters62]

Is having a soil compaction test completed normal for a permit requirement?
I'm in NC and currently having my land leveled for an upcoming 30x50 shop. The local permit office said I need this test completed before my permit and concrete go in.
No problem, so I thought.
No one seems to know who completes this test, not the excavation companies, not the concrete guys. It took several calls to the permit office for them to just give me a single company that could do it.
So I'm confused because everyone has buildings going up in my community but no one seems knowledgeable on this seemingly important first step.
I talked to the company that supposedly completes the test but even they seemed like it was odd that I was requesting it, almost like they'd never done it outside a large engineering project.
So, if this a normal thing? I still have no idea how much this is even going to cost.

 

[Skooterj]

I've only heard of needing a residential compaction test if you are not building on virgin soil. Are you sure they do not mean a perc test for septic system? Or are you building on a landfill or gravel dump?

 

[adrenalinejeeper]

It is a normal thing in around here, especially if dirt is being moved (which is most builds...).

A geotechnical engineering company is probably who you are looking for. That is who does it around here. Sometimes it is the actual engineer who will come out, larger companies will send a technician to do it on behalf of the engineer, then the engineer stamps the compaction/soils report.

 

[Mytoolsupply]

Have they already started building the pad?

 

[Renegade1LI]

Definitely not the norm, but they may have a reason, the lab will need to get soil samples first, usually 3-5 grabs to come up with a baseline. Once you complete excavation and compact then they will test a few areas, again seems unusual for a residential build, unless your new building is commercial.

 

[duneslider]

For whatever reason, they require it where I am just on the approach. Which is just the little bit of concrete from the road to the sidewalk. I believe it is because they don't want the approach to sink and then cause damage to the sidewalk which the city has to maintain.

Compaction tests aren't required anywhere else on residential here unless you over excavate and have to fill back in and recompact.

 

[apeters62]

Thank you for the replies. The permit office said if dirt was being brought in, then a 2000psi compaction test must be performed. We didn't bring in a lot but my yard did slope a bit.
I contacted the only semi local geotech engineering company and they said they could do the test but their only engineer had just quit so they couldn't stamp it. Which makes the whole thing pointless.
So, at this point the dirt work is done but I can't move to concrete without the test and permit.

 

[duneslider]

Thank you for the replies. The permit office said if dirt was being brought in, then a 2000psi compaction test must be performed. We didn't bring in a lot but my yard did slope a bit.
I contacted the only semi local geotech engineering company and they said they could do the test but their only engineer had just quit so they couldn't stamp it. Which makes the whole thing pointless.
So, at this point the dirt work is done but I can't move to concrete without the test and permit.

Does the city require a stamped test? When we did ours it was just form you filled out, the guy put down his name, number, company, and the reading from the machine. That was all we had to do. In fact, it was just our excavator that did it. He has one of the machines, just sets it down on the ground in a few locations and hits the button. It was like the size of a small tool box.

 

[apeters62]

Does the city require a stamped test? When we did ours it was just form you filled out, the guy put down his name, number, company, and the reading from the machine. That was all we had to do. In fact, it was just our excavator that did it. He has one of the machines, just sets it down on the ground in a few locations and hits the button. It was like the size of a small tool box.

Assuming they do require it. I only say that because the company they gave me to call didn't offer what you're speaking off. They also want $500+ for the test, which seems steep but I have nothing for comparison at this point.

 

[duneslider]

We had to have a civil engineer check our "hole" before we did our foundation and I am pretty sure $500 is what he charged for that. He didn't do anything more than a site inspection though and I know his report did NOT have a stamp on it, it was just on company letterhead. The only thing we had to have stamped was the structural engineering, everything else was just forms that the various people had to submit.

 

[Leaflessshadetree]

$500 for someone to travel (how much time and miles) to your location, do any type of work, then provide any type of documentation and keep a record doesn't sound expensive to me.

 

[apeters62]

$500 for someone to travel (how much time and miles) to your location, do any type of work, then provide any type of documentation and keep a record doesn't sound expensive to me.

Expensive is relative. A $100 building permit and the city has to travel to my site 3-4 times, inspect and report. Granted that's not a private company.

 

[duneslider]

Well, if your building permit is only $100 that's a bargain in my book. The building permit for my house was $28k. Sewer connection fee was $4k. Power connection was $1500. Gas was $2300.

Building permit for a shop in my area would be considerably more than $100.

 

[Crawlin]

What part of NC?

 

[apeters62]

What part of NC?

Yadkinville

 

[apeters62]

Update: Permitting once someone to come out with a "penetrometer" and test for 2000psi compaction. It doesn't have to be signed off by an engineer. However, the company that permitting gave me to call, they wanted to take soil samples and test in a lab and basically do way more than what's needed. On that note, still trying to find a company that can do this. Thank you for everyone's comments.

 

[duneslider]

In my area, I see asphalt guys doing this test all the time before they pave. The paved a parking lot near my house last week and I saw the guy out on the compacted base testing, they paved the following day. I regularly see pavers and excavators doing this in my area, might be another avenue you can check.

Honestly though, having a civil engineer come and also test the soils isn't a bad idea and I don't think the $500 is an unreasonable charge. I do understand your position and that you just want to get moving along. I am also sure there are other geotechnical engineers in your area than just the one the city told you about. Any new subdivisions going in around you? Maybe swing by and find the super and ask who they are using?

 

[apeters62]

In my area, I see asphalt guys doing this test all the time before they pave. The paved a parking lot near my house last week and I saw the guy out on the compacted base testing, they paved the following day. I regularly see pavers and excavators doing this in my area, might be another avenue you can check.

Honestly though, having a civil engineer come and also test the soils isn't a bad idea and I don't think the $500 is an unreasonable charge. I do understand your position and that you just want to get moving along. I am also sure there are other geotechnical engineers in your area than just the one the city told you about. Any new subdivisions going in around you? Maybe swing by and find the super and ask who they are using?

Great ideas. I'll continue to check around and did find one more lead on a excavating company that may be able to assist.

 

[ybnormal]

you may also have gotten the new employee at the county office who doesn't know how to properly read code and evaluate what is needed. I had that issue about 3 yrs ago. go back and talk to someone else and insist on a plain language translation detailing what is required and have them write it down

 

[gmcgeo]

When i lived in AZ we had compaction tests on anything that was dug 5"s and wider. In PA i have yet to see it done unless on the Roads, however i doubt that gets done

 

[Bluearmflames]

I would see if someone could come out and do a wildcat dynamic test. It’s strictly a load bearing test for compaction. No soil samples are needed unless required.

 

[Crawlin]

Yadkinville

I am up the road a little ways from you; near Sparta. I built a building on fill a couple years ago and used Catawba Valley Engineering and Testing in Hickory. They will do it. Not sure on cost. 828-578-9972

Also might see if you could get by with a proof roll test. Take a loaded dump truck and roll drive area to make sure it does not pump or sink up.

 

[JWILLIE1977]

Compaction and soil bearing capacity are two completely different tests.

Pocket penetrometer does not measure the compaction of the material. It measures the bearing capacity of the material. Normally performed on undisturbed native soils.

Compaction testing is done with a nuclear density gauge, or other apparatus (sand cone) after lab testing has been done on fill materials to determine the materials optimum density & moisture content.

Again. Two different tests.

As mentioned previous. Contact a geotech engineer, or a construction materials testing lab in your area.


Side note, it's always amazing to me that the agency responsible for overall approval has no clue.

 

[JoeMcGov]

Compaction and soil bearing capacity are two completely different tests.

Pocket penetrometer does not measure the compaction of the material. It measures the bearing capacity of the material. Normally performed on undisturbed native soils.

Compaction testing is done with a nuclear density gauge, or other apparatus (sand cone) after lab testing has been done on fill materials to determine the materials optimum density & moisture content.

Again. Two different tests.

As mentioned previous. Contact a geotech engineer, or a construction materials testing lab in your area.


Side note, it's always amazing to me that the agency responsible for overall approval has no clue.

All of this^^^. And to be able to determine the optimum density and moisture content they WILL HAVE TO get a sample of the dirt/fill material and test & analyze it in the laboratory.

 

[bugman-74]

FWIW - here in AZ, a "special inspection" was required under my permit and I had to submit compaction test (Soil/Aggregate field density test - nuclear method) to the county for the imported material (fill dirt). Had a local Geotech Engineering firm do it. Total cost was $464. You will get a report with data similar to what is attached.

 

[billspit]

See if Yadkin County has a county engineer and contact them for info.

 

[brownbagg]

i charge $200 for the proctor and $100 hour, two hours minimum,
no issues $400

 

[Dozerhand]

As a side note try not to run over his machine when he sets it down. I had a co worker who did that. When we called the small town police and told them we had a nuclear accident out on the highway they really didn't know how to respond to that.

 

[metlmunchr]

soil compaction vs soil bearing capacity - Earthwork/grading engineering - Eng-Tips

Is there a relation between soil compaction test value and soil bearing capacity value?

www.eng-tips.com

This explains the difference between a soil compaction test, which is reported as a percentage, and a soil bearing test which is reported in pounds per square foot (psf, not psi)

The county seems to be asking for a compaction test that's going to somehow determine load bearing capability. As the linked article explains, no direct relationship exists between the two.

Permitting and inspections here in NC is primarily a jobs program for otherwise unemployable members of the good ol' boy network and unqualified individuals with political connections.

 

[555]

Required in our west Georgia county.

 

[Bill T]

It appears that Yadkinville uses the North Carolina Bukilding code as the code of record. I have attached a link to this document (the relevant section): https://codes.iccsafe.org/content/NCBC2018/chapter-18-soils-and-foundations

 

[barnee]

How deep was your deepest fill area for the building?

 

[brownbagg]

The county seems to be asking for a compaction test that's going to somehow determine load bearing capability.

you are really over thinking this, soil bearing is different between different type of soil, but most is about 2000 psf. what you need to worry about is settlement, compacted material will handle that

compacted fill will determine footing size

 

[MeanGene427]

Did this many times over my career, normal procedure is obtain a soil sample, take it to the lab and dry it, then pound a "curve" for the nuke tester to compare to. They will set the tester with those numbers, pound a hole in your compacted soil, and insert the probe of the tester and run the test. The nuke tester is registered to the technician, and he typically takes it home for chain of custody. When testing asphalt, no hole/ probe, tester sits flat. Sometimes the client (like CalTrans) will require core samples to be cut to verify. And the amount of radioactive material is very small, but if it gets run over, it is a genuine nuclear accident with all the bells & whistles

 

[captaindiode]

Any updates