ricky_005
Basic Member
Posts:313
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| 22 Apr 2014 05:53 PM |
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Can anyone give me some ideas of the cost for a half day to perform dynamic compaction for a 5,000 sf area? Project is located in Georgia A sample of a contractor performing dynamic compaction. https://www.youtube.com/watch?v=nRUp9chzTdI |
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FBBP
Veteran Member
Posts:1215
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| 22 Apr 2014 07:14 PM |
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It would appear that all it is is a pile driver with a foot.
Can I ask why you would need this equipment? |
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ricky_005
Basic Member
Posts:313
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| 22 Apr 2014 11:23 PM |
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Red loamy soil about 500' from the Chattahoochee river that's going to very difficult to get 98% compaction for a slab on grade home. Using dynamic compaction, I could easily reach 98%+ and modify the soil structure as far down as 20' using this method. Site is only one acre and would be rather difficult to use a crane where they drop a 5 ton or so block of steel 40' to 60' in the air to performing the dynamic compaction.
The problem will most likely be finding a company which has the hydraulic driver to do it. |
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dmaceld
Veteran Member
Posts:1465
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| 23 Apr 2014 01:11 AM |
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Posted By ricky_005 on 22 Apr 2014 11:23 PM
Red loamy soil about 500' from the Chattahoochee river that's going to very difficult to get 98% compaction for a slab on grade home. Using dynamic compaction, I could easily reach 98%+ and modify the soil structure as far down as 20' using this method. Site is only one acre and would be rather difficult to use a crane where they drop a 5 ton or so block of steel 40' to 60' in the air to performing the dynamic compaction.
The problem will most likely be finding a company which has the hydraulic driver to do it.
I wonder if it might not be more economical to build on pilings like they do in New Orleans area? |
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| Even a retired engineer can build a house successfully w/ GBT help! |
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ricky_005
Basic Member
Posts:313
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| 23 Apr 2014 02:34 AM |
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I'm on a hill top, not below sea level....
I just need one for about 6 Hours ....... shouldn't be that costly. Dynamic compaction is the most cost effective measures you can take!
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jonr
Senior Member
Posts:5341
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| 23 Apr 2014 09:43 AM |
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...would be rather difficult to use a crane where they drop a 5 ton or so block of steel 40' to 60'
According to this there is no replacement for big weights falling large distances. |
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FBBP
Veteran Member
Posts:1215
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| 23 Apr 2014 11:37 AM |
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Ricky - what compaction does your geo tech engineer call for?
Has your structural engineer said he can't design a reinforced slab for your soil conditions?
What is the risk of the shock waves damaging nearby infrastructure, wells etc? |
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dmaceld
Veteran Member
Posts:1465
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| 23 Apr 2014 11:46 AM |
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Posted By ricky_005 on 23 Apr 2014 02:34 AM
I'm on a hill top, not below sea level....
Pilings aren't used because of flood plain. They are used because of soft soil, which from what you said above, is what you are dealing with.
I just need one for about 6 Hours ....... shouldn't be that costly. Dynamic compaction is the most cost effective measures you can take!
Don't bet on it. A rig that big maybe $300 to $500 per hour plus a grand or more mobilization charge. But I suppose 5 grand may not be that much in the grand scheme of things. A post-tensioned slab might be your answer. They use those a lot in the Gulf Coast area where the soil is like an air mattress on a swimming pool! |
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| Even a retired engineer can build a house successfully w/ GBT help! |
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jonr
Senior Member
Posts:5341
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| 23 Apr 2014 12:57 PM |
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It would be interesting to see more comparison data (cost and effectiveness) for all the options (driven pilings, screw pilings, floating waffle or tensioned slab, compaction). I understand that some soils just won't compress. |
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Alton
Veteran Member
Posts:2157
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| 23 Apr 2014 04:22 PM |
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Posted By ricky_005 on 23 Apr 2014 02:34 AM
I'm on a hill top, not below sea level....
I just need one for about 6 Hours ....... shouldn't be that costly. Dynamic compaction is the most cost effective measures you can take
Ricky,
If dynamic compaction is not available, then consider http://www.pearsonpilings.com/residential.html |
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Residential Designer &
Construction Technology Consultant -- E-mail: Alton at Auburn dot Edu Use email format with @ and period .
334 826-3979 |
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ricky_005
Basic Member
Posts:313
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| 23 Apr 2014 05:59 PM |
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I have not had a soil test done yet, but I feel as though the soil will test around the 1500 psf which is a quite poor. I will have to pour a rather wide footer to compensate for the poor soil conditions.
There are homes along the river in my location built on slabs, some with raised slabs. I'm just looking at taking some cheap measures to improve the soil conditions to help minimize any settling years down the road.
Lake evevation 635' / Lot Elevation 682' = 47' above full pool so no risk of flooding.
Pilings are to expensive, and would not be required.
There is a 30' to 40' deep bottom/valley between my property and the adjacent home/hill top so the impacts will be isolated.
I'm thinking cost for the equipment and operator should be around $300 hour. |
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jonr
Senior Member
Posts:5341
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| 23 Apr 2014 06:45 PM |
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With a frost protected shallow foundation (FPSF) mat/raft slab, you have no footings and much less load per sq foot to cause settling. It's not linear, so a little less load causes much less settling. |
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dmaceld
Veteran Member
Posts:1465
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| 23 Apr 2014 06:50 PM |
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Posted By ricky_005 on 23 Apr 2014 05:59 PM
I have not had a soil test done yet, but I feel as though the soil will test around the 1500 psf which is a quite poor. I will have to pour a rather wide footer to compensate for the poor soil conditions 1500 psf isn't that poor, really. That's the code required assumption here in Idaho unless soil tests prove otherwise. When I built my house the total load on the footing on the tallest wall, about 14' on one gable end, was low enough that I needed only a 16.5" wide footing for 1500 psf soil rating. I put larger square footings at house corners where multiple roof and floor loads converged. Of course, a two story wall, if that's what you are building, would need a wider footing. You really do need to get the soil test done so you know for certain what your starting point is. Your need for compaction may be a lot less than you're thinking. As I used to tell folks during my days in quality assurance, "If you start from an unknown starting point, and go a known distance in a known direction, you end up at ......... an unknown ending point!" A sign on the wall at work read, "In God we trust. All others, please bring data!" |
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| Even a retired engineer can build a house successfully w/ GBT help! |
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ricky_005
Basic Member
Posts:313
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| 23 Apr 2014 07:00 PM |
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@ jonr
Could you find a pic on google images and show a cross section detail of what you are referring to.
Keep in mind this is in mid Georgia the southeast.
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ricky_005
Basic Member
Posts:313
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| 23 Apr 2014 07:05 PM |
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My worst fears are, it may only make it to 1000 psf and will require a rather wide spread footer. Yes, we are planning on doing a 2 storie home and I'm concerned about the weight of a 6" ICF core wall on loamy silty soil.
If the cost of modifying the soil proves to be to costly for ICF wall construction, my other alternative is to use a light weight SSIP system for the walls.
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jonr
Senior Member
Posts:5341
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| 23 Apr 2014 07:15 PM |
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Basically like this, although they didn't draw the vertical foam insulation needed to cover the edge. Note that the thickened portion may be repeated further in (like a waffle). Or the entire slab can be made the same thickness. |
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ricky_005
Basic Member
Posts:313
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| 23 Apr 2014 08:08 PM |
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Yea a waffle design might work well enough if the waffling is tight enough to prevent the slab from breaking up (long term) from the dead loads. |
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agagent3
Basic Member
Posts:134
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| 24 Apr 2014 12:02 PM |
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I worked with a group of farmers to build an corn ethanol plant. The build site was on plainfield loamy sand. We used the dynamic compaction method because it was the least cost alternative. I can't remember the dollar amount but it was substantial. I recall going out to the site while doing the compaction and being able to easily feel the impacts. Soil boring showed that it worked better than expected. |
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