HomeMy WebLinkAboutSoil Investigation 07.13.2018CÍVCO Engine ering, Inc.
CivÍl Engineering Consultonts
P.O. Box t758
3ó5 West 50 North, Suite W-l
Vernol, Utoh 84078
July 13, 2018
Brian Quintana
Clayton Homes
671 23 Road
Grand Junction, CO 81505
Dear Brian,
Subiect SoiI lnvestigation - $cott Residence in Parachute, Gotorado
I am writing thís letter to report the tindings of a soil investigation that was conducted at the proposed
sile for the Scott residence in Parachute, Colorado. The investigation entailed the analysis of one soil
sample that was taken from the construction site at approximately the location and bearing depth of the
proposed foundation. Testing of the soil sample included a sieve analysis and Atterberg Limits testing.
The test results were used to classify lhe soil sample as 'OH' according to the Unified Soil Classification
System. Copies of the soil data are included with this letter.
OH soils include organic clays of medium to high plast¡c¡ty and organic silts. Literature suggests that
OH soils are likely to have relatively low bearing capacity. I recommend a soil bgaring capacity of 1500
psf be used for foundation design.
Over the years, a number of studies have been conducted in an effort to correlate soil shrink-swell
potential to atterberg limit data. According to one study, liquid limits less than 50% and plasticity
indexes less than 25o/o, generally suggest a soil will have a low shrinklswell potential. Using the
conclusions of that study, the atterberg test results for this soil sample suggest that the soil has a low
potential for expansion. The liquid limit for the soil was found to be 31% which is within the low-
expansion limit, and the plasticity index for the soil was found to be 13% which is also within the low-
expansion limit. Please note that Atterberg limits tests do not address soil mineralogy and thus may be
limited in their ability to reliably predict soil shrink-swell potential.
ln addition to soil expansion, frost heave of the foundation is also a possibílity. Therefore it is important
that structural foundations bear below the local frost penetration depth or be frost-protected with
insulation. Frost heave results from soil moisture expanding as il freezes. Therefore, every effort
should be taken to límit soil moisture in the vicinity of foundations. Walkways, driveways, and ground
surfaces should be graded to flow away from the foundation. Gutter down-spout outlets should
discharge at least five feet away from the foundation. Vegetation requiring significant watering should
not be planled near the foundation,
No testing was done to determine the soil's collapse potential. ln my experience, foundation failures
due to soil collapse are generally even more catastrophic than failures due to soil expansion. ln every
instance of soil collapse failure that I have investigated, the damaged home was located at the mouth
of a pronounced drainage, such as a canyon or gully where the soil has been deposited alluvially by
intermittent runoff water flows.
Alluviallydeposited soils are typically not very dense and derive their strength from mineraf bonds that
form between soil particles. When these soils become wet, the mineral bonds dissolve, allowing the
soil particles to consolidate (collapse) under any load that is in excess of that which existed when the
mineral bonds originally formed.
Phone (435[89-?448 * Fax (435F89-4485
Emoíl : vqncekíng@civcoengineeríng. com
. Page2 July 13, 2018
Verify that the project site is not at the mouth of any obvious draínage. The aforementioned methods
for lowering the risk of frost heave are also key to lessening the risk of soil collapse failure.
ln summary, the soil under the foundalion was not specifically tested to determine expansiveness but
was found to have a liquid limit and a plasticity index that suggest the soil to have a low potential for
expansion. Likewise the soil was not specifically tested to determine bearing capacity but was found to
be of a type having lower characteristic bearing capacities. For design purposes, a maximum 1500 psf
bearing capacity is recommended. The home owner should make every effort to keep moisture from
being introduced to the soil near the foundation. Any future purchaser of the home should be apprised
of the underlying soil characteristics and the importance of keeping moisture away from the foundation.
This concludes my report. Please note that this investigation was performed for the purpose of
providing general information regarding the soil underl$ng the proposed home and makes no
prediction of foundational performance. ïhis report should not be regarded as documentation of a
geotechnical investigation as I am not a geotechnical engineer. Please contact me if you have
questions regarding this report.
Sincerely,
Vance V. King, PE
Engineer
CIVCO Engineering, lnc.
Enclosure
Cc:Project File
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Rernarks
Dave Argo
From:
Sent:
To:
Cc:
Subject:
Attachments:
Quintana, Brian < Brian.Quintana@ClaytonHomes.com >
Wednesday, August 22, 2018 9:42 AM
Dave Argo
Brooke Winschell
MCcarty Soils
1-80713 soil rpt - brian.pdf
Attached is the soils report from the engineer for 3000 county Rd 301 in Parachute
I am currently working on a better plot plan to scale showing the whole property and set backs.
Thanks
Brian Quintanø
Home Consultant
Clayton Homes
Home Center 1037
O: 970.245.9039
C:97O.4O4.7065
From: Va nce <va nceking@civcoengineering.com>
Sent: Tuesday, August 2L,2OI8 9:08 AM
To: Ruse, Shawn
Cc: Quintana, Brian
Subject: RE: IEXTERNAL] RE: Scott in Rulison
Here are scans of what is on its way to you in the mail.
You will receive:
Wet-stamped prints (4 copies)
Wet-stamped soil report (1 coPy)
lnvoice (L copy)
Thanks,
Vance King,
CTVCO Engineering, Inc
PO Box 1758
Vernal, UT 84078
435-789-5448
From: Ruse, Shawn Imailto:Shawn.Ruse@ClaytonHomes'com]
Sent: Friday, August 77, 20IB 4:14 PM
To: Vance
Cc: Quintana, Brian
Subject: Re: IEXTERNAL] RE: Scott in Rulison
Looks good
Thank You
Shawn Ruse
1