QOD 10/25/04

Originally Posted By: clawrenson
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The following is related to residential building structures.



Ontario Home Inspections Inc.

Originally Posted By: tallen
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I believe Gravel is the correct answer.


Clay can be very unstable.


http://www.nachi.org/tips/0203.gif


Originally Posted By: jpope
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Stability was not the question - strength was. Gravel is as “unstable” as sand.


Now granite, on the other hand. . .

I'm really not sure what the question really asks but I picked sand ![icon_biggrin.gif](upload://iKNGSw3qcRIEmXySa8gItY6Gczg.gif)


--
Jeff Pope
JPI Home Inspection Service
"At JPI, we'll help you look better"
(661) 212-0738

Originally Posted By: tallen
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Which of the following is the strongest soil type?


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Originally Posted By: bbadger
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I am with Todd, I voted for gravel. icon_smile.gif



Bob Badger


Electrical Construction & Maintenance


Moderator at ECN

Originally Posted By: kmcmahon
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As an ex-soil tester, I knew the answer to this one!!! icon_biggrin.gif



Wisconsin Home Inspection, ABC Home Inspection LLC


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Originally Posted By: Ryan Jackson
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Hmm…IRC table R401.4.1 seems to like crytalline bedrock.



Ryan Jackson, Salt Lake City

Originally Posted By: tallen
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That was not one of the choices. icon_wink.gif


Originally Posted By: Ryan Jackson
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I know Todd, just a little side note. icon_smile.gif



Ryan Jackson, Salt Lake City

Originally Posted By: tallen
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icon_razz.gif I knew you knew just razzing you.


Originally Posted By: Ryan Jackson
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And I knew that you knew that I knew. I was just razzing you nachi_sarcasm.gif



Ryan Jackson, Salt Lake City

Originally Posted By: tallen
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Well, now that we know that we both knew what the other knew what we are >…wait a minute I am lost icon_confused.gif


Originally Posted By: Blaine Wiley
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Sand is not unstable if compacted properly. I find very few structure failures or settlement issues here, as compared to our clay soil in VA., although it is a loam here, not simply sand.


Originally Posted By: kmcmahon
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Most homes here are built on sandy soil. very few foundation problems…sometimes after 50 years or so, but ya gotta expect some of those.



Wisconsin Home Inspection, ABC Home Inspection LLC


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Originally Posted By: tallen
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Most areas around here have"caleche" (sp) about 2-4’ down. This stuff is as hard as granite. Not many foundation problems.


It takes hours of serious Manuel labor to dig a hole just to plant a tree.

Most people will use a jackhammer to dig a footer if there is not a backhoe available.


Originally Posted By: five.five
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As a lurking newbie on this site, I look forward to the Q.O.D., and the Q.O.D. postings have not been as consistant as they have in the past.


I look forward to the Q.O.D. as it helps me get ready for the State exam (from Hell).


My point is, what happened to the Q.O.D., and the right answer getting posted consistantly.


just asking the question, not meant as an attack on anyone.

BTW, I checked sand, and was the first to vote for it.

So what is the correct answer ?


Originally Posted By: clawrenson
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Based on bearing strength - gravel is the answer. Caveat - foundation design is a highly specialized field of geotechnical engineering. Allowable foundation pressure (psf) gravel 3000, sand 2000, clay 1500.



Ontario Home Inspections Inc.

Originally Posted By: ccoombs
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Sand is a great material to build on. But it has some limitation. Sand does not compact. It needs to be confined to be strong. There is a documented case of a 4 story building in Argentina that was built on sand collapsing because dogs were digging at the edge of the foundation. Also, Japan and California has issues with liquefaction. When there is pressure on sand mixed with water it can loose all its strength and turn to a liquid state.


Originally Posted By: roconnor
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Keep in mind that the soils mother nature deposited are not usually uniform like ya might find in a supply yard or delivered to a jobsite. There is usually a mix of types within any deposit, and whatever the majority of the type is determines it’s classification.


So a typical "Gravel" deposit will usually also have smaller particles mixed in to fill up most of the gaps/voids to make it a very stable and strong bearing soil.

There are always exceptions to everything, and you can run across fairly uniform deposits ... like deposits of pretty uniform very fine wet sands, which can "liquefy" in an eathquake as mentioned.

Just my 2-nickels ... ![icon_wink.gif](upload://ssT9V5t45yjlgXqiFRXL04eXtqw.gif)


--
Robert O'Connor, PE
Eagle Engineering ?
Eagle Eye Inspections ?
NACHI Education Committee

I am absolutely amazed sometimes by how much thought goes into doing things wrong

Originally Posted By: ccoombs
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Robert


I just read the statement in your signature line:

"I am absolutely amazed sometimes by how much thought goes into doing things wrong"

There is so much truth to that statement. I spend a lot of time on jobs just shaking my head in amazement.

Curtis