HomeMy WebLinkAboutGeotechnical Investigation 06.15.16Huddleston -Berry
%nginccring d 'resting, LLC
MountainView Construction Services, LLC
1413 Munro Avenue
Rifle, Colorado 81650
Attention: Mr. Jerry Caves
Subject: Geotechnical Investigation
Lot 5 Creek Side Estates
Rifle, Colorado
Dear Mr. Caves,
640 White Avenue, Unit B
Grand Junction, Colorado 81501
Phone: 970-255-8005
Fax: 970-255-6818
Info d huddlesionberry.com
.lune 15, 2016
Project#01273-0016
This letter presents the results of a geotechnical investigation conducted by Huddleston -Berry
Engineering & Testing, LLC (HBET) for Lot 5 of the Creek Side Estates subdivision in Rifle,
Colorado. 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 with a slight slope down to the southwest.
Vegetation consisted primarily of grasses and weeds. The site was bordered to the north and east
by residential properties, to the west by a vacant lot, and to the south by a shared driveway.
Subsurface Investi ation
The subsurface investigation included four test pits as shown on Figure 1 -- Site Plan. The test
pits were excavated to depths of between 2.0 and 8.0 feet below the existing ground surface.
Typed test pit logs are included in Appendix A.
As indicated on the logs, the subsurface conditions at the site were fairly consistent. The test pits
generally encountered 1.0 foot of topsoil above brown, moist to wet, medium dense silty, clayey
sand soils to the bottoms of the excavations. Groundwater was encountered in TP -1 at a depth of
4.0 feet at the time of the investigation.
Lot S Creed: side
Huddleston -Berry
#01273-0001 �$` In,nmY`i to M}flC
06/15/16
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 250 pci may be used for structural fill
consisting of crusher fines, pit -run, or base course. Footings subject to frost should be at least 36
inches below the finished grade.
As discussed previously, water soluble sulfates were detected in the site soils in a concentration
of 0.4%. This concentration of sulfates represents a severe degree of potential sulfate attack on
concrete. Therefore, Type V cement is recommended for construction at this site.
Any stemwalls or retaining walls should be designed to resist lateral 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 fluid unit weight of 50 pcf in areas
where no surcharge loads are present. Lateral 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 floor slabs be constructed above a minimum of 18 -inches of
structural fill 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 the native soils, below the topsoil, that have been scarified to a depth of 12 -inches,
moisture conditioned, and compacted to a minimum of 95% of the standard Proctor maximum
dry density, within f 2% of the optimum moisture content as determined in accordance with
ASTM D698.
Drainaize Recommendations
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 irrigation within ten feet of foundations be minimized.
HBET recommends that downspout extensions be used which discharge a minimum of 5 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. In addition, an impermeable membrane is recommended below subsurface downspout
drain lines to limit the potential for leaks in the subsurface drains to impact the structure. Dry
wells should not be used.
As discussed previously, shallow groundwater was encountered at the time of the investigation.
Therefore, if a structural floor and crawlspace are utilized, a perimeter foundation drain is
recommended. In general, the perimeter foundation drain should consist of prefabricated drain
materials or perforated pipe and gravel systems with the #towline of the drain a minimum of 1.0
foot below the bottom of the foundation (at the highest point). The perimeter drain should slope
at a minimum of 1.0% to daylight or to a sump.
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FIGURES
APPENDIX A
Typed Test Pit Logs
Ituddleston-1JcrryLugincering& resting, 1.1 c.' TEST PIT NUMBER TP -2
` 640 White Avcouc, Unit B PAGE i OF 1
Grand Junction, CO 81501
970-255-X005
970-255-6818
CLIENT Mountainview Construction Services PROJECT NAME L,ot 5 Creek Side Estates
PROJECT NUMBER 01273-0416 PROJECT LOCATION Rifle. CO
DATE STARTED 611116 COMPLETED 511116 GROUND ELEVATION TEST PIT SIZE
EXCAVATION CONTRACTOR Clieni GROUND WATER LEVELS:
EXCAVATION METHOD TrackhlBackhoe AT TIME OF EXCAVATION dry
LOGGED BY CM CHECKED BY -MAB _ AT END OF EXCAVATION dry
NOTES 24hrs AFTER EXCAVATION dry
ATTERBERG
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Iuddleston-Berry Engineering & Testing. I.t.0 TEST PIT NUMBER TP4
640 While Avcnuc, unit B PAGE I OF l
' Grand Junction, CO 81501
970-255-8005
970-255.6818
CLIENT Mountainview Construction Services PROJECT NAME Lot 5 Creek Side Estates
PROJECT NUMBER 01273.0016 PROJECT LOCATION Rine, CO
DATE STARTED 611116 COMPLETED 611116 _ _ GROUND ELEVATION TEST PIT SIZE
EXCAVATION CONTRACTOR Client GROUND WATER LEVELS:
EXCAVATION METHOD TrackhBackhoe AT TIME OF EXCAVATION dry
LOGGED BY CM CHECKED BY MAB _ AT END OF EXCAVATION dry
NOTES 24hm AFTER EXCAVATION dry
ATTERBERG
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Nom„ qs Huddleston -Berry Fnginccring & Testing, LLC MOISTURE -DENSITY RELATIONSHIP
° 640 White Avenue, Unit B
Grand Junction, CO 81501
970-255.6005
970-255.6818
CLIENT Mountainview Construction Services PROJECT NAME Lot 5 Creek Side Estates
PROJECT NUMBER 01273-0016 PROJECT LOCATION Rifle CO
ibu
Sample Date: 611/2016
Sample No.: 1
145 Source of Material: TP -2
Description of Material SILTY CLAYEY SAND SC -SM
Test Method: ASTM D698A
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TEST RESULTS
Maximum Dry Density 119.0 PCF
Optimum Water Content 13.0 %
10 15
WATER CONTENT,
GRADATION RESULTS (% PASSING)
#200 #4 314"
48 100 100
ATTERBERG LIMITS
LL PL PI
24 18 6
Curves of 100% Saturation
for Specific Gravity Equal to:
2.80
2.70
2.60
30
