How long should I let new ground settle before putting in posts on piers?

   / How long should I let new ground settle before putting in posts on piers? #41  
Helical piers are an excellent option for the post bases. I would forgo the slab for a few years to see what happens.
If you have a geotechnical engineer nearby, have them come and take a proctor and do a few penetrometer tests or nuclear density tests.
 
   / How long should I let new ground settle before putting in posts on piers? #42  
Also most dozers have low ground pressures, ie they don’t do a good job of compacting. A Cat D6 has ground pressure of about 8psi.
 
   / How long should I let new ground settle before putting in posts on piers? #43  
Maybe not for buildings, and I am sure MF231 knows better than any of us, but I will wager dozers have done more soil compacting than any other machine in our lifetime -- taking into acct roads, berms, rights of way, mining reclamation, etc. I realize that is tangntial and not a building foundation though so the point is well taken. We ARE talking "an old pole barn" here I repeat from a few posts back.
 
   / How long should I let new ground settle before putting in posts on piers? #44  
Maybe not for buildings, and I am sure MF231 knows better than any of us, but I will wager dozers have done more soil compacting than any other machine in our lifetime -- taking into acct roads, berms, rights of way, mining reclamation, etc. I realize that is tangntial and not a building foundation though so the point is well taken. We ARE talking "an old pole barn" here I repeat from a few posts back.
You would lose that wager. Nothing is worse at compacting soil then a dozen. Mine weighs 40,000 pounds. My small tractor weighs 4,000 pounds. It's tires will sink into the ground where the tracks have gone over new dirt. When building up a pad for myself, I put a full yard in the bucket of my backhoe and I drive over every inch of soil repeatedly. I do 2 inch lifts and compact each layer this way.
 
   / How long should I let new ground settle before putting in posts on piers? #45  
You would lose that wager. Nothing is worse at compacting soil then a dozen. Mine weighs 40,000 pounds. My small tractor weighs 4,000 pounds. It's tires will sink into the ground where the tracks have gone over new dirt. When building up a pad for myself, I put a full yard in the bucket of my backhoe and I drive over every inch of soil repeatedly. I do 2 inch lifts and compact each layer this way.
Nope. I disagree. I wager dozers have done more soil compacting than any other machine in our lifetime. I stand by that.

Dozers are THE primary tool for soil spreading and compacting world-wide for essentially all roads, mine reclamation projects, berms, rights of way, earthen dams, major highway construction, etc. That's universally known, undeniable and it does not matter what your's weighs. We got into this discussion about a pole barn site. I said I was talking aside from that in this added discussion (post 43 plus) which I said was just comment NOT to do with buildings or foundations. Buildings and foundations are significant but make a smaller fraction of earth moving and soil compacting compared to highways, roads, and industrial sites of all sorts -- most of which is done by dozers. They are sometimes supplemented by "sheeps hoof " rollers for very loose problem areas.

Since you say I lose that wager, what were you thinking did most of the soil smoothing and compacting in our lifetime?
 
   / How long should I let new ground settle before putting in posts on piers? #46  
I can’t understand why/how anyone thinks they’re going to actually compact 5-10’ of soil at once.
You’d be lucky to get the top 1 foot compacted. If you must compact the fill, push it back into a pile and compact it with a vibe compactor in proper lifts.

Better yet, just do it right from the start and move the building onto virgin or dig below the fill into virgin soil you'll curse the day when your building begins to sink.
Why do all that work and expense and take chances
 
   / How long should I let new ground settle before putting in posts on piers? #47  
Nope. I disagree. I wager dozers have done more soil compacting than any other machine in our lifetime. I stand by that.

Dozers are THE primary tool for soil spreading and compacting world-wide for essentially all roads, mine reclamation projects, berms, rights of way, earthen dams, major highway construction, etc. That's universally known, undeniable and it does not matter what your's weighs. We got into this discussion about a pole barn site. I said I was talking aside from that in this added discussion (post 43 plus) which I said was just comment NOT to do with buildings or foundations. Buildings and foundations are significant but make a smaller fraction of earth moving and soil compacting compared to highways, roads, and industrial sites of all sorts -- most of which is done by dozers. They are sometimes supplemented by "sheeps hoof " rollers for very loose problem areas.

Since you say I lose that wager, what were you thinking did most of the soil smoothing and compacting in our lifetime?
If you want to say that dirt was spread with a dozer and then people drove over that dirt, or built on it more then properly compacted soil, then I'll give you that. If you are trying to argue that a machine with it's weight spread out over a pair of tracks is capable of compacting the soil so it doesn't settle afterwards, then you are wrong.

To get maximum compaction, you have to use a vibratory roller. Sheepsfoot rollers work the best for soil, but smooth drum are used all the time for road too. You also have to have the proper amount of moisture in the soil so it will bond with itself. This is done every time you need proper compaction in order to build anything on top of it.

A dozer is a very good tool at spreading soil, and moving it short distances. It's a horrible took at compacting soil. In our lifetime, the machine that has done most of the spreading of soil is probably a dozer, but a Grader might actually have done more miles of smoothing soil if the math was ever done. I honestly don't know which has smoothed more dirt. I do know that a vibratory roller has compacted more dirt then both of those combined since neither a dozer or a grader is capable of compacting soil.

Did you build something and compact the soil with a dozer? Your disagreeing with common knowledge makes me think you did it wrong and you are trying to defend what you did.

sheepsfoot.jpg
 
   / How long should I let new ground settle before putting in posts on piers? #48  
Yeah, Eddie is correct. If you have driven by or been around a construction site it might look like bulldozers are spreading soil and compacting but they are not doing the compacting part. I spent 37 years as a land surveyor on all sorts of construction sites, I also did nuclear machine density testing. The pic Eddie posted of a vibratory sheep’s foot roller is the most common tool.
 
   / How long should I let new ground settle before putting in posts on piers? #49  
Nope. I disagree. I wager dozers have done more soil compacting than any other machine in our lifetime. I stand by that.

Dozers are THE primary tool for soil spreading and compacting world-wide for essentially all roads, mine reclamation projects, berms, rights of way, earthen dams, major highway construction, etc. That's universally known, undeniable and it does not matter what your's weighs. We got into this discussion about a pole barn site. I said I was talking aside from that in this added discussion (post 43 plus) which I said was just comment NOT to do with buildings or foundations. Buildings and foundations are significant but make a smaller fraction of earth moving and soil compacting compared to highways, roads, and industrial sites of all sorts -- most of which is done by dozers. They are sometimes supplemented by "sheeps hoof " rollers for very loose problem areas.

Since you say I lose that wager, what were you thinking did most of the soil smoothing and compacting in our lifetime?
Think back many years when tractors were the primary tool for farming. The problem was that when soils were soft the tires sunk in and when the moisture was right the soil became compacted which is bad for planting. Then Holt née Caterpillar came out with tracked tractors. Sinking and compaction problems greatly reduced because the ground pressure exerted by tracked equipment is a fraction of tired tractors.

The weight per SF on a tracted tractor in many applications is less than a person standing!
 
   / How long should I let new ground settle before putting in posts on piers? #50  
Several folks have suggested the most cost effective idea assuming you have some flexibility with the building site. Shift it into the hill to put all of it on undisturbed ground or at least enough to put the downhill post bases within reach of whatever you've got for an auger.

While you're shifting it, and even if you're not, leave enough room for some drainage on that uphill side, both for roof spill and overland flow. Ditch it deeper if you need to cut off subsurface flow.

Regarding compaction - compacting just with a dozer is a dream. Several posters have accurately noted the low ground pressure from a dozer, and ground pressure with or without vibration (along with proper moisture content) is what it takes to get compaction. You'll see dozers spreading material in lifts on lots of job sites but if they're building anything of consequence that dozer is going to be towing a sheepsfoot roller or being followed by a self propelled roller.
 
 
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