HomeMy WebLinkAboutSoil and Foundation Investigation 05.31.22 Revised 08.08.22j$$
Engineering Inc.
CTvlUCCOTECIIHICAI,
SOIL AND FOUNDATTON IT{YtrSTIGATION
r.ORA
MAIN RESIDENCE AI\[D BARN/AI}U
4C RAIYCH
GARFTELD CREEK ROAD, CR #312
NEW CASTLE
PrN 218334300058
GARFIELD COIINTY, COLORADO
PROJECT NO. 22-3661
MAY 31,2022
REVISED AUGUST 8,2022
PREPARED T'OR:
BRENT SCOTT
P.O. BOX 5559
EAGLE, CO 81637
B rent. S cott@mountainbeveB&q. Fgn
P.O. Box 724,Eagle, CO 81631 Tel. (970) 390-0307 $flvw.LKPEggipeerins.com
TABLE OF CONTENTS
EXECTJTTVE SU\{I\{ARY
SCOPE OF STUDY
SITE DESCRIPTION..
PROPOSED CONSTRUCTION ......
FIELD I}.I\{ESTIGATION
SUBSURFACE SOIL AND GROUNDWATER CONDITION
FOIJ}IDATION RECOMMENDATIONS .
SLAB CONSTRUCTION
CRAWL SPACE
RETAINING WAI.LS
I.JNDERDRAIN SYSTEM..
SITE GRADING AND DRAINAGE...-...........
I.AWN IRRIGATION
2
2
2
3
3
3
4
5
6
6
6
?
7
8LIMITATION
AREAMAP. ......DRAWINGNO.2
FIGTJRES
LOCATION SKETCH
SUBSTIRFACE ffGLORATION LOGS..,
GRAIN.SIZE DISTRIBUTION. . .
PERIMETER DRAIN DETAIL...
STRUCTURAL FILL WTTFI GEOGRID ..
OVBREXCAVATION AND COMPACTTON. ..
..DITAWINGNO. 1
....FIGURE NO's l-3
.FIGURE NO.4
.FICURE NO. 5
.FIGURE NO. 6
FI(.lIIRtr NN ?
P.O. Box 724,Eagle, CO 81631 Tel (970) 390-0307 ww."'il.lkpengineerine.com
E)(ECUTIVE SI'MMARY
The proposed banr/residence should be supported with
conventional tirye spread footings, designed for an allowable soil
bearing pressure of 1500 psf. They should construct the footings
on the undisturbed silty to sandy clay to silty-clayey sand with
cobbles and boulders or on geogrid improved strucfiral fill. Sce
Foundation Recommendations.
SCOPE OF'STUDY
This report presents the resuits of a subsurface Soil and Foundation Investigation for a
proposed single-family residence and a barn with atr apartnent at 4C Ranch, New Castle,
County Road 3 12, PIN 2 I 83 34300058, Garfield County, Colorado. The purposc of the
subsurface soil and foundation investigation was to determine thc engineering characteristics of
the foundation soil and to provide recommendations for the foundation design, grading, and
drainage. Geologic hazard studies are otttside of our scope of sewices.
SITE DESCRIPTION
The 4C Ranch is 1163.959 acres property, south ofNew Castle, Garlield County,
Colorado. The proposed building sites are located in tbe northwest portion of Section 3, as
shown on the area map, drawing 2 and on the Location Sketch, Drawing 1. The building sites for
the proposed barn/residence are on meadows. Vegetation within the proposed building site
LKP Engineering, [nc,
3
consiEted of grass. The topography within the selected building areas (where the test pits were
excavated) is relatively flat. Drainage is to the north and northwest. Garfield Creek and Garfield
Creek Road are to the north of the proposed building site for the main residence. The area was
surrounded by mountains.
PROPOSED CONSTRUCTION
We understand that the proposed main residence will be two story, wood frame
consbuction without a basement, on a concrete foundation, and the barn building will also be
two story wood frame constmction with an aparbent above on one side, and a large barn on the
other. We anticipate loads to be light, typical of residential consbruction.
If the finalized plans differ significantly from the above understanding, they should
notify us to reevaluate the recommendations of this report.
EIELD II{VESTIGATION
The field investigation, conducted on May 25,2A22, consisted of logging xad sarnFling
tbree test pits. Approximate locations of the test pits are shown on Drawing No. I, We show the
soil profile of the test pits on the Subsurface Exploration Logs, Figurc No's I through 3. Soil
samples for laboratory soil analysis and observation were taken at selected intervals. We
understand that your excavator dug the test pits prior to our site visit.
STIBST]RFACE SOIL AND GROTJNDWATER CONDTTION
Thc soil profiles encountered in the three test pits were fairly uniform, consisting of 2 to
5 feet of topsoil over brown to light brown, silty-sandy clay to silty-clayey sand, gravelly with
cobbles and varying amounts of boulders. Moisture content was high (15 to 177o) but free
P.O. Box 724,Eagle,CO 81631 Tel. {970) 390-0307 www.LKPEnqineqring.cor4
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grouud water or bedrock were not encountered in any of the test pits. We sampled the soil in the
test pits at random intervals. The samples were tested for natural moisture content and grain-size
disribution. The test results are shown on Figure number 4.
FOTJIYDATION REC OMMENDATIONS
The proposed main residence and the barn with an additional dwelling uniq should be
supported witb conventional t5pe spread footings, designed for an allowable soil bearing
pressure of 1500 psf. They should construct the footings on the undisturbed silty to sandy clay to
silty-clayey sand, gtavelly with cobbles and some boulders-
Ifunsuitable soils (thick layers of topsoil) are encountered within the foundation
excavation, the proposed residence and the additional dwelling unit sbould be supported with
conventional type spread footings consbucted on a structqfa!fr!1. designed for a maximum
allowable soil bearing pressure of 2000 psf. TlE.fg-atings Will be nlaced on ouerscavsled 4d-
compacted. strug4rql,.{ill inprovedwith thfee (3) la.vers of Tensar. Triacial Geaghl. as shown
on the attached detail, Sftrcnural Fill with Geogrid, Figure No. 7. Minus 3-inch road base or
other approved, imported stnrchrral material, free from topsoil, organics and volcanic ash, can be
used as a structural fill. A minimum of four feet of the unsuitable subgrade materiai (topsoil or
other soft or wet soils) should be overexcavated under the entire foundation. The width of the
overexcavation should be according to the attached overexcavation aud compaction detail with a
minimum of five feet on the outside perimeterof Ole excavation.
The completedfoundatian excavation should be observed and/or tested by the
undersigned engineer to verifu that the soil canditions encountered during cowttaction are as
anticipated in this report.
We recornmend a minimum width of 16 inches for the continuous footings and 2 feet for
the isolated footing pads. Continuous foundation walls should be reinforced top and bottom to
span an unsupported length ofat least I0 feet'
The proposed foundation should be set at a minimum depth of four feet below the
finished grade or at the minimum depth required by tlre local building code. The foundation
P.O. Box 7Z4,Etgle,CO 81631 Tel. (970) 390-0307 www.LKlEngineering'Sgm
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excavation should be free from excavation spoils, frost, organics and stasding water. We
recommend proof-rolling of the foundation excavation. Soft spots detected during the proof-
rolling, should be removcd by overexcavation. Any overexcavation witbin the proposed
foundation should be bacldilled, in 8 inches loose level lifu and compacted to 100% ofthe
maximum dry density and within 2 percent of the optimum moisfure content ss determined in a
laboratory from a Standard Proctor test (ASTM n-698). A stnlchrral fill, placed nnder footings
should be tested by a qualified professional.
SLAB CONSTRUCTION
The nahrral on-site soils, exclusive of topsoil and organics, are suitable to support lightly
loaded slab-on-grade consbuction. In the event that the thick topsoil layer is also encountered
under the proposed slab on grade areas, the unsuitable soil should be overexcavated and replaced
with a non-swelling, structuralrtll,.fejlrbreed w,ith layers of Tensar Gegwid, as described above
in the foundation recommcndations section. Tte subgrade for tbe slab-on-grade construction
should be proof compacted to detect and remove soft spots. They should backfitl overexcavated
soft spots and other underslab fill with the on-site soil, free from topsoil and organics, or other
suitabls material compacted to a minimum of 95 percent of the maximum standardProctor
density (ASTM D-698). Suitable material should be free from topsoil, organics and rock
fragments greater than 3 inches.
The concrete slab should be consfircted over a 4-inch layer of clean gravel consisting of
-3l4-inch gravel with at least 50% retained on the No. 4 sieve and less than 3 percent passing the
No.200 sieve.
They should reinforce the concrete slab-on-grade and score control joints according to
the American Concrete Institute requirements and per ttre recommendations of the desiguer to
reduce damage due to shrinkage. The concrete slab should be separated from the foundation
walls and columns with expansion joints to allow for independent movement without causing
damage.
P.O. Box 724,Eagle, CO 81631 Tel. (970) 390-030? www.LKPEnsineering.com
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CRAWL SPACE
If topsoil is encountered in the crawl space areas, it should be overexcavated and
replaced with non-organic soil. The organic matter contained in the topsoil will decompose with
time releasing odors (like row sewage) that might notbe acceptable by the homeowner. Crawl
spaces should be vented according to the building code.
RETAINING WALLS
Foundation walls retaining earth and retaining stnrctures that are laterally supported
should be designed to resist an equivalent fluid density of 60 pcf for an "at-restn condition.
Lateralty unrestrained stmcturss, fetaining the on-site earth, should be designed to resist an
equivalent fluid density of 40 pcf for tle "active" case.
The above design recommendations assume drained baclcfill conditions and a horizontal
bacldill surface. Surcharge loading due to adjacent structwes, weight of temporary stored
construction materials aod equipment, inclined bacldll and hydrostatic pressure due to
undrained backfill should be incorporated in the design. They should ty to prevent the buildup
of hydrostatic preszure behind tbe retaining wall.
Passive earth pressure of360 psfcan be used for the lateral pressure against the sides of
the footings. Resistance to sliding at the bottom of the footings can be calculated based on a
coefficient of frictiou of 0.5. Undisturbed soil or a stuctural fill compacted to 100 percent of the
murimum dry densiff and within 2 percent of the optimum moisture content will be used to
resist lateral loads at the sides of the footings.
UNDERI}RAIN SYSTEM
To reduce the risk of surface water infiltrating the foundation subsoil, we recommeud
installation of a foundation perimeter drain (see Figure No. 5). The foundation perimeter drain
should consist of a 4-inch diameter, perforated pipe, sloped to a suitable gavtty outlet, atall4
I
P.O. Box 7Z4,Eagle,CO 81631 Tel. (970) 390-0307 www.LKPEneineering.com
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inch per foot for flexible or at a 1/8 of an inch for rigid pipe. The bottom of the trench adjacent
to the footing should be lined with a polyethylene moisture barrier glued to the foundation wall.
The drain pipe should bo oovored with a minimum of 6 inches of -3/zt-inch frce-draining
granular material. Geotextile (Mirafi l40N or equivalent) should be used to coverthe free-
draining gravel to prevent siltation and clogging ofthe drain. The bacldll above the drain should
be granular material to within 2 feet of the ground surface to prevent a huildup of hydrostatic
pressuTe.
SITE CRADING AI{D DRAINAGE
The following recommendations are general. Exterior backfill should be compacted at or
nEar the optimum moisture cont€nt to at least 95% of the manimum standard Proctor density
under pavement, sidewalk and patio areas and to at least 90% of the maximum standard Proctor
density underlandscaped areas. They should use mechanical methods of compaction. Do not
puddle the foundation excavation.
The site surrounding the building stnrcture should slope away from the buildiug in alt
directious. A minimum of 12 inches in the first l0 feet is recommsrrded in unpaved areas, and
tbree inches in the first 10 feet in paved areas. The top of the granular fouadation bacHill should
be covered with a minimum of I foot of relatively impervious fi[ to reduce the potential of
surface water infiltating the foundation subsoils.
Surface water naturally draining toward,the proposed building site should be diverted
around and away from it by rneans of drainage swales or other approved methods. The roof
drains and downspouts should extend and discharge beyond the limits of the backfill.
LAWN IRRIGATION
It is not recommended to introduce excess water to the foundation soils by installing
sprinkJer systems next to tbe building. The installation sf thc sprinkler heads should ensurc that
the spray from the heads will not fall within l0 feet of foundation walls, porches or patio slabs.
P.O. Box 7}4,Eagle,CO 81631 Tel. (970) 390-0307 www.LKPEngineeriqg.com
I
Lawn irrigation must be controlled.
LIMITATION
This report has been prepared according to locally accepted Professional Geotechnical
Engineering standards for similar methods of testing and soil conditions at this time. The type of
soil testing was selected by the owner as the prefered method for the soil and foundation
investigation over a soil and foundation investigation with a drill rig. There is no otherwarcanty
either expressed or implied.
The findings and recommendations of this report are based on field exploration,
laboratory testing of samples obtained at the specific locations shown on the Location Sketch,
Drawing No.l and on assumptions stated in the report. Soil conditions at qlher-lg.catiofu m?Y.
vary. rl|hich mav notbe,cgrqe evident until the fou.qd+tion,expavatio.,n iS completed. If soil or
water conditiom seem different fromthose described in this reporq we should be contacted
immediately to reevaluate the recommendations of this report. We are not responsible for
technical interpretation by others of the data presented in this reporl
This reportbas been prepared for the exclusive use ofBrent Ssott, for the specific
application to the proposed Main Residence and Barn with an ADU at 4C Ranch, New Castle,
County Road 312, PIN 218334300058' Garfield Coun$t, Colorado.
Sincerely,
LKP ENGINEERING,INC.
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Luiza Petrovska, PE
J:\_W? X4-LKP!2022U2J 606CLAY-PITS.DOC(
P.O. Box ',l24,Eagle,CO 81631 Tel. (970) 390-0307 www.LKPEngineerine.com
NoTE: tHE LoCATK)N oF THE TEST PnS ls
APPRSX{VATE. lr 1S NOT BAS€D ON A SURVEY.
LOCATION SKETCH
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P.O. Box 7?{, Eogle, C€ 81631
5SO-0307
4C RANCH
CR 312, NEW CASTLE
PIN: 216 334 3{nO 58
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22-3619
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4C RANCH
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PIN:218 334 3000 58
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Dcpartment of the Nauy, Nowl Facllitles Engineering Commond
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Engineering, lnc.
P.O. Box 724,
TGa (97o) 3sq-os07
co 81531
OVEREXCAVATION & RECOMPACTION
4C RAT{CH
CR312, NEWCASTLE
PIN:218 334 3UX) 58
GARFIELD COUNTY. COLORADO
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22-3619
N.T.S.
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4C RANCH
CR312. NEWCASTLE
PIN:218 3A4 3000 Sg
GARFIELD COUNTY, COLORADO
7