Foundation in Sandy soil

Drive piles, coated with Polyurea, so they will not decompose for a very long time, cause PH imbalance in the adjacent water supply or...

Use plasticized concrete slurry and Halliburton "style" quesan pressurized pump to force the concrete into the pilot hole under 60psi., forcing the concrete to push against the outer walls of the hole and forcing a bulb in the base of the hole to prevent sinking.

The pressure of the concrete using quesan's forces any water which may be below ground, out of the sand around the actual drilled hole because of the pressure of the force of the concrete aides in wicking the water away from the mixture. Leachate is kept to minimum, as the compaction of the outer soil bands prevents saturation of the slurry. This system works well at forming stable concrete footings under very demanding conditions.

Various additional concrete stabilizers are known to aid in flow and concrete structure, during drying which can improve the quality of the process, exponentially; such as fly ashe.

Piles work great where water is less of an issue of the depth of the total length of pile being driven or when the pile exceeds the top soil depth, such as when you drive to bedrock.

For a heavy building you may be requires to hammer the piles an additional amount, usually 150 hits, after reaching bed rock, to set the pile and prove the cavity structure under ground does not crack open the bedrock, exposing a fisher or subterranean cavern.

If you do one of these processes, and smaller systems are now being used widely for home sized buildings; you can then use light weight slabs, such as pre-cast concrete or block and concrete columns, building up stem walls or you can form your concrete slab at grade, now the footings are driven into the sub-soil, re-enforcing the slab at various strategic placements around the foundation. you will no longer rely on the traditional bell-footer for structural strength of the foundation.

Smaller screw type quesan drills have become very effective choice where pre-planning for weakened soil situations is foreseen and employed. It is far cheaper to sink a few drilled quesan footings, then having to jack the cracked foundation at all corners and force concrete under the slab through holes in the living and dining room floors, after the fact. as the concrete fly ash slurry is forced into the hole while the bit is turning under ground, through a core pipe located within the center of the drill auger bit, the sand is kept out of the process, while the bit is removed slowly, allowing the slurry to be forced under pressure during the raising of the auger bit.

The main problem is; after the house has become unstable or a sink hole has become evident, the total loss and amount of concrete required to fill the void created as the soil erodes, becomes nearly impossible to estimate.

Many sink hole ridden properties have been deemed too expensive to complete or repair, after the fourth truck of concrete is poured into the ground, with no end in site. pre-assessment of the sub-soil often times would have prevented such calamities.

You may possibly utilize land adjacent to water encroached properties with added safety and deeper penetration into once un-usable real estate, as the systems discussed, allow for stability engineering to be assessed prior to expenditure of funds, by careful core drilling analysis of the sub-soil system; even in lakes.

I have pictures of a swimming pool which withstood category 4 hurricane winds, directly on the beach of a major hotel, which did not lose any footing or a drop of grade or degree of level, while the sand of the beach was washed well over 25 feet below the original grade of the pool. You could stand under the pool foundation and not touch the bottom of the pool with your hands.

It was full of water and level after the entire beach was gone!

The 26 - 8"x8"x 38' pile type footings, the builder installed as he seen as minimum requirement for long term reliability and insure-ability, are the reason you may still swim in this pool at Destin, Florida; today.

Unfortunately the beach stairs once used to get to the shore are now quite a bit shy of the landing. The last step is a doozie!

Dear Contributor,

Congratulations for a very good answer to the thread on foundation footing.You mention " polyurea " as a means of protection for the (presumably : wooden )piles. As I may, for an extensive project use such wooden piles I would appreciate your indication of the makers name of that preservative , and if you have it , an indication of the expected duration in : years of this protection. ( I was planning to use pressure application -from the top of the piles prior to driving- before hammering them in. In the past I have used tar- based creosote in sea water.)

Thank you for your assistance

Labor Omnia Vincit

I have heard of using "sand washers" what I'm told is, they dig down pour a 12 - 18" pad say 10 or 12' in diameter with re-bar. From there they go up with a 36" column to the next pad bout 6' up with a monolithic pour and then whatever above that for the footing. Never seen it done but it sounds solid to me. Kinda like a stabilizer pad on a crane.

You left out a key item. Where is it located? This will determine the frost depth. If you pour concrete above the frost depth and it freezes, regarless of how thick it is, it will be damaged unless it has air entrainment. Frost heave can add an uplift of over 2000 pinod per square foot. Besure to place the foot below it. Check with your local building code inspector for the depth if you do not have access to the local code books.

I didn't notice if the question regarding will the structure sink or concrete crack was addressed previously. First you need to determine if the soil will support you structure adequately with in design parameters, is the total, differential and seismic settlement acceptable and the bearing pressure greater than the applied loads. Is seismic liquefaction a risk. These are issues you address by knowing the density and gradation of the stratigraphy and water depth underlying your proposed structure. Piles or any deep foundation is usually a last resort to mitigate deep unsuitable strata where it is not cost effective to over-excavate and replace with engineered fill

One contributor has indicated that you left out a key item, namely frost. I would suggest that you have left out nearly all the key items necessary to resolve your problem.

If you want any kind of answer that makes sense, the geotechnical information needs to be alot better. What do the boreholes say? Is it sandy clay, clayey sand, gravelly sand? In short, what kind of sand is it and to what depth?

The normal course of events should be a geotechnical investigation (which can be cost effective) and advice from the geotechnical expert as to which foundation is the most suitable given the ground conditions.

On balance, it is always best to commision a geotechnical investigation, even if it is by the contractor supervised by the engineer using simple trial pits of small depth. The consequences of bad design in the ground are too important to merit skipping this stage of work.

The point I was making, is the concrete slab can be removed from the equation when piles or Quesan's are used. There is no need for monolithic slabs under every single building in the world. The structural integrity can change over time, no matter how much you pay a geological surveyor. By taking the foundation expense and using it as pillars to support the total foundation, we can use wood or plastics or steel and polymer composites as foundations. They can be designed to flex and bend.

Why? Because they can be properly supported by deep set piles.

You can save yourself the grief of re-thinking every project with 2 criterion:

1) Is the ground too rocky for excavation?

a) Yes, we don't have a thing to worry about unless the ground opens up and swallows our building.

b) No, we can dig to our heart's content to bedrock, (if necessary and affordable).

2) Can we use the concrete or wood or plastic in a vertical fashion and guarantee the structure will stand for years, (unless the ground opens up and swallows our building)?

a)Yes, the piles can be steel, concrete or wood and they can be sealed so the environment is protected with polymers.

b)No, the rocky substrata is fouled with massive rocks, (we go back to #1), or we cannot get passed 50 year old building practices and cannot see past the end of our noses and we MUST continue to pour concrete everywhere we go and try to fix cracked slabs as if it is our religion, (especially if the intellectuals at the local building department force us to such construction practices).

I have slab systems designed to replace concrete. They are cost effective, mold and fire resistant, can be assembled as checkerboard, can float, are easy to plumb and run electrical through; even after the building is erected. The system create jobs on location and is faster, stronger and better than controlling concrete slab preparation and materials QC in a third world country. (As if that's even possible.)

If you ask any architectural student why the numerous Wright buildings are considered failures in the world of construction and archetecture, it is clearly because the mortar and brick, in brick and mortar; is the failure. It is too expensive to test, analyze and replace or retrofit bad materials in a timely or efficient fashion. The cost is not just the testing, it is the mandatory time it takes to test and respond. There is no time or extra money for this process, which fails and cost everyone of us. It is and will always be too easy to use "Fillers" and cheat the performance desired in order to save money or because of variables we cannot cost defer.

Let's just say 1 out of ten homes in your sandy swampland, desert or polar region, are going to crack and your local building expert, (who's brother owns the concrete company's truck repair firm); decides to force you to use a slab system. Who will cover you when you go bankrupt, regardless of the fancy slabs you have constructed, when the testing is found flawed or was incompetently managed?

I'd like to see the face of the foreign owner of your new buildings, when he calls to let you in on the repairs required to his investment, (especially in a place that is not so keen on, "Whoops; we goofed!").

The question should be simple.

Can I dig and drive piles or screw into the earth and use Quesans?? (I don't see anything forcing me to think inside the slab box.)

Do I absolutely need a concrete floor, or is it just what I have been fooled into thinking I need to use? What's wrong with alternative flooring systems?

Why not laminate the foundation with other materials instead of using concrete?

(I'll bet garbage makes great flooring, after it's recycled).

If the earth opens up, all the degrees and QC testing in the world won't matter. (We cannot really keep up with it all anyways).

Ask Frank L. Wright's conservator's. They are $$ broke because of such "Best Practices". The Waterfall will bankrupt the endowments set aside, when repaired. Unfortunately, every other FLR building left to the DOI is in the same boat. The Mortar is the weak point and we are NEVER going to be able to track every wheelbarrow of mud globally.

If we can't endow "design architecture" to the world without admitting we goofed up and we are still using the same ridiculous practices, like block walls and concrete slabs, which are bankrupting the Wright Foundation; what have we learned?

The earth is not green, it is mostly Blue. I'm going blue.

I m interested in your checker board concrete slab replacement

can someone tell me about foundations without using concrete (using metals) any links if someone can plz...