HomeMy WebLinkAboutSubsoils Report for Foundation DesignHuddleston-Berry
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Shining Light Services
PO Box 759
Fruita, Colorado 81521
Attention: Mr. Tyler Didonato
Subject: Geotechnical Investigation
2T4Limberpine Circle
Parachute, Colorado
Dear Mr. Didonato,
2789 Riverside Parkway
Grand Junction, Colorado 81501
Phone: 970-255-8005
Info@huddlestonberry. com
June27,2022
Project#02490-0001
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This letter presents the results of a geotechnical investigation conducted by Huddleston-Berry
Engineering & Testing, LLC (HBET) for 214 Limberpine Circle in Parachute, Colorado. The
site location is shown on Figure I - Site Location Map. The proposed construction is anticipated
to consist of a single-family residence. The scope of our investigation included evaluating the
subsurface conditions at the site to aid in developing foundation recommendations for the
proposed construction.
Site Conditions
At the time of the investigation, the site was open and fairly flat. Vegetation consisted of grasses
and weeds. The site was bordered to the northwest by a vacant lot, to the northeast by
Limberpine Circle, to the southwest by open land, and to the southeast by a residential property.
Subsurface Investigation
The subsurface investigation included one test pit at the site as shown on Figure 2 - Site Plan.
The test pit was excavated to a depth of 8.0 feet below the existing ground surface. A typed test
pit log is included in Appendix A.
The test pit encountered 1.0 foot of topsoil above tan, dry to moist, soft to medium stiff silty clay
with sand soils to a depth of 6.0 feet. The clay soils were underlain by tan, dry to moist, medium
stiff to stiff silty clay with sand, gravel, cobble, and boulder soils to the bottom of the excavation.
Groundwater was not encountered in the subsurface at the time of the investigation.
Laboratorv Testins
Laboratory testing was conducted on samples of the native soils collected from the test pit. The
testing included grain-size analysis, Atterberg limits determination, natural moisture content
determination, and maximum dry density and optimum moisture content (Proctor) determination.
The laboratory testing results are included in Appendix B.
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214 Limberpine Circle
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The laboratory testing results indicate that the native clay soils are slightly plastic. In general,
based on the Atterberg limits and our experience with similar soils in the vicinity of the subject
site, the shallow native clay soils are anticipated to be slightly collapsible.
Foundation Recommendations
Based upon the results of the subsurface investigation and nature of the proposed construction,
shallow foundations are generally recommended. Spread footings and monolithic (turndown)
structural slab foundations are both appropriate alternatives. However, in order to provide a
uniform bearing stratum and reduce the risk of excessive differential movements, it is
recommended that the foundations be constructed above a minimum of 24-inches of structural
fill.
In addition, based upon information provided to HBET, a foundation from a previous structure
may be present at the site. If an existing foundation is encountered during the new foundation
excavation, the existing foundation should be completely removed and replaced with structural
fill.
The native clay soils, exclusive of topsoil, are suitable for reuse as structural fill; provided
particles in excess of 3-inches in diameter are removed. Imported structural fill should consist of
agranu|ar,non-eXpanSiue,w@g,materialapprovedbyHBET.
For spread footing foundations, the footing areas may be trenched. However, for monolithic slab
foundations, the structural fill should extend across the entire building pad area to a depth of 24-
inches below the turndown edges. Structural fill should extend laterally beyond the edges of the
foundations a distance equal to the thickness of structural fill for both foundation types.
Prior to placement of structural fill, it is recommended that the bottom of the foundation
excavation be scarified to a depth of 6 to 8 inches, moisture conditioned, and compacted to a
minimum of 95%o of the standard Proctor maximum dry density, within +2%o of the optimum
moisture content as determined in accordance with ASTM D698. Structural filI should be
moisture conditioned, placed in maximum 8-inch loose lifts, and compacted to a minimum of
95%o of the standard Proctor maximum dry density for fine grained soils and 90o/o of the modified
Proctor maximum dry density for coarse grained soils, within t2o/o of the optimum moisture
content as determined in accordance with ASTM D698 and D1557, respectively.
Structural fill should be extended to within O.l-feet of the bottom of the foundation. No more
than 0.l-feet of gravel should be placed below the footings or turndown edge as a leveling
course.
For structural fill consisting of the native soils or imported granular materials, and foundation
building pad preparation as recommended, a maximum allowable bearing capacity of 1,500 psf
may be used. In addition, a modulus of subgrade reaction of 150 pci may be used for structural
fill consisting of the native soils and a modulus of 200 pci may be used for suitable imported
structural fill. Foundations subject to frost should be at least 36 inches below the finished grade.
Water soluble sulfates are common to the soils in Western Colorado. Therefore, at a minimum,
Type I-II sulfate resistant cement is recommended for construction at this site.
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2Z:V008 AIL PROJECTS\02490 - Shining Light SeNices\02490-000 I 2 1 4 Limberpine Circle\200 - Geo\02490-000 I LR062 I 22 doc
214 Limberpine Circle
#02490-0001
06t21/22
Any stemwalls or retaining walls should be designed to resist laterul earth pressures. For backfill
consisting of the native soils or imported granular, non-free draining, non-expansive material, we
recommend that the walls be designed for an equivalent active fluid unit weight of 45 pcf in
areas where no surcharge loads are present. An at-rest equivalent fluid unit weight of 65 pcf is
recommended for braced walls. Laterul earth pressures should be increased as necessary to
reflect any surcharge loading behind the walls.
Non-Structural Floor Slab and Exterior Flatwork Recommendations
In order to limit the potential for excessive differential movements of slabs-on-grade it is
recommended that non-structural floating floor slabs be constructed above a minimum of 18-
inches of structural filI with subgrade preparation and fill placement in accordance with the
Foundation Recommendations section of this report. It is recommended that exterior flatwork be
constructed above a minimum of 12-inches of structural fiIl.
Drainase endations
Grading and drainase are critical to the lons-term performunce of the structure. Grading
around the structure should be designed to carry precipitation and runoff away from the
structure. It is recommended that the finished ground surface drop at least twelve inches within
the first ten feet away from the structure. It is also recommended that landscaping within five
feet of the structure include primarily desert plants with low water requirements. In addition, it
is recommended that automatic irrigation, including drip lines, within ten feet of foundations be
minimized.
HBET recommends that surface downspout extensions be used which discharge a minimum of
15 feet from the structure or beyond the backfill zone, whichever is greater. However, if
subsurface downspout drains are utilized. they should be carefully constructed of solid-wall PVC
and should daylight a minimum of 15 feet from the structure. In addition, an impermeable
membrane is recommended below subsurface downspout drains. Dry wells should not be used.
General Notes
The recommendations included above are based upon the results of the subsurface investigation
and on our local experience. These conclusions and recommendations are valid only for the
proposed construction.
As discussed previously, only one test pit was conducted at the site. Therefore, the precise nature
and extent of subsurface variability may not become evident until construction. As a result, it is
recommended that HBET provide construction materials testing and engineering oversight
during the entire construction process. In addition, the homeowner and any subcontractors
working on the project should be provided a copy of this report and informed of the issues
associated with the presence of moisture sensitive subgrade materials at this site.
HuddlesistuBsft!
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JZ:\2008 ALL PROJECTS\02490 - Shining Light Services\02490-0001 214 Limberpine CircleU00 - G@\02490-0001 LR062122.doc
214 Limberpine Circle
#02490-0001
0612U22
It is important to note thut the recommendations herein are intended to reduce the risk of
structural movement and/or damagq to varving deqrees. associated with volume chanqe of the
native soils. However. HBET cannot lons-term chunses in subsurface moisture
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conditions and/or the nrecise or extent of volume chanse.Where sisnificant
increuses in subsurfsce moisture occur due to Door grading, imDroper stormwater
management, utilitv line fuilure, excess irrigation, or other cause. either during construction
or the result of actions of the propertv owner, several inches of movement are oossible. I!
addition. anv failure to complv with the recommendations in this report releases lluddleston-
Berrv Ensineerins & Testins, LLC of anv liabilitv with resard to the structure performance.
We are pleased to be of service to your project. Please contact us if you have any questions or
comments regarding the contents of this report.
Respectfully Submitted:
Huddleston-Berry Engineering and Testingo LLC
Michael A. Berry, P.E.
Vice President of Engineering
4Z:D008 ALL PROJECTS\02490 - Shining Light Services\02490-0001 214 Limberpine CircleV00 - Geo\02490-0001 LR062122.doc
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Dale crealed:5/6/2Q22
Last Data Uploaded:5/6/2022 3:52:30 AM
FIGURE 1
Site Location Map
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Last Data Uploaded:5/6/2022 3:52:30 AM
FIGURE 2
Site Plan
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2789 Riverside Parkway
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970-255-8005
GRAIN SIZE DISTRIBUTION
CLIENT Shininq Liqht Services PROJECT NAME 214 Limberpine Circle
PROJECT NUMBER 02490-OOO1 PROJECT LOCATION Parachute, CO
U.S. SIEVE OPENING IN INCHES I U.S. SIEVE NUIVIBERS I
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Huddleston-Berry Engineering & Testing, LLC ATTERBERG LIMITS' RESULTS
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CLIENT Shinino Lioht Services PROJECT NAME 214 Limberpine Circle
PROJECT NUMBER 02490-0001 PROJECT LOCATION Parachute. CO
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PROJECT NAME 214 Limberpine Circle
PROJECT LOCATION Parachute, COPROJECT NUMBER 02490-000'1
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Riverside Parlavay
Grand Junction, CO 81501
970-255-8005
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Test Method (manual):ASTM D698A
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