HomeMy WebLinkAboutSoils Report 05.18.2020Kumar & Associates, Inc.®
Geotechnical and Materials Engineers
and Environmental Scientists
An Employee Owned Company
5020 County Road 154
Glenwood Springs, CO 81601
phone: (970) 945-7988
fax: (970) 945-8454
email: kaglenwood@kumarusa.com
www.kumerusa.com
Office Locations: Denver (HQ), Parker, Colorado Springs, Fort Collins, Glenwood Springs, and Summit County, Colorado
GENE
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SUBSOIL STUDY
FOR FOUNDATION DESIGN
PROPOSED NEULEIB RESIDENCE
LOT 12, BLOCK 7, BATTLEMENT CREEK VILLAGE 2
344 MEADOW CREEK DRIVE
GARFIELD COUNTY, COLORADO
PROJECT NO. 20-7-256
MAY 18, 2020
PREPARED FOR:
EDWIN L. NEULEIB
C/O RUSSELL CARTWRIGHT
284 MEADOW CREEK DRIVE
PARACHUTE, COLORADO 81635
(russeca rt(a),2m a i i.co iii)
TABLE OF CONTENTS
PURPOSE AND SCOPE OF STUDY - 1 -
PROPOSED CONSTRUCTION - 1 -
SITE CONDITIONS - 1 -
FIELD EXPLORATION - 2 -
SUBSURFACE CONDITIONS - 2 -
FOUNDATION BEARING CONDITIONS ...- 3 -
DESIGN RECOMMENDATIONS - 3 -
FOUNDATIONS - 3 -
FLOOR SLABS - 4 -
SURFACE DRAINAGE - 5 -
LIMITATIONS - 5 -
FIGURE 1 - LOCATION OF EXPLORATORY BORING
FIGURE 2 - LOG OF EXPLORATORY BORING
FIGURES 3 and 4 - SWELL -CONSOLIDATION TEST RESULTS
TABLE 1- SUMMARY OF LABORATORY TEST RESULTS
Kumar & Associates, Inc. ® Project No. 20.7-256
PURPOSE AND SCOPE OF STUDY
This report presents the results of a subsoil study for the proposed Neuleib residence to be
located on Lot 12, Block 7, Battlement Creek Village 2, 344 Meadow Creek Drive, Battlement
Mesa, Garfield County, Colorado. The project site is shown on Figure 1. The purpose of the
study was to develop recommendations for the foundation design. The study was conducted in
accordance with our agreement for geotechnical engineering services to Edwin L. Neuleib c/o
Russell Cartwright dated May 4, 2020.
A field exploration program consisting of an exploratory boring was conducted to obtain
information on the subsurface conditions. Samples of the subsoils obtained during the field
exploration were tested in the laboratory to determine their classification, compressibility or
swell and other engineering characteristics. The results of the field exploration and laboratory
testing were analyzed to develop recommendations for foundation types, depths and allowable
pressures for the proposed building foundation. This report summarizes the data obtained during
this study and presents our conclusions, design recommendations and other geotechnical
engineering considerations based on the proposed construction and the subsurface conditions
encountered.
PROPOSED CONSTRUCTION
The proposed residence will be a one-story wood -frame structure with an attached garage located
in the area of our exploratory boring shown on Figure 1. Ground floors will be structural over
crawlspace in the living area and slab -on -grade in the garage. Grading for the structure is
assumed to be relatively minor with cut depths between about 2 to 4 feet. We assume relatively
light foundation loadings, typical of the proposed type of construction.
If building loadings, location or grading plans change significantly from those described above,
we should be notified to re-evaluate the recommendations contained in this report.
SITE CONDITIONS
The subject site was vacant at the time of our field exploration and the ground surface appeared
mostly natural. The terrain is relatively flat with a strong slope down to the northeast at grades
Kumar & Associates, Inc. ® Project No. 20-7.256
2
estimated from about 5 to 8%. Vegetation consists of grass and sagebrush. There is a residence
on the adjacent Lot 11 to the west.
FIELD EXPLORATION
The field exploration for the project was conducted on May 6, 2020. One exploratory boring
was drilled at the location shown on Figure 1 to evaluate the subsurface conditions. The boring
was advanced with 4 inch diameter continuous flight augers powered by a truck -mounted CME -
45B drill rig. The boring was logged by a representative of Kumar & Associates.
Samples of the subsoils were taken with 1% inch and 2 inch I.D. spoon samplers. The samplers
were driven into the subsoils at various depths with blows from a 140 pound hammer falling 30
inches. This test is similar to the standard penetration test described by ASTM Method D-1586.
The penetration resistance values are an indication of the relative density or consistency of the
subsoils. Depths at which the samples were taken and the penetration resistance values are
shown on the Log of Exploratory Boring, Figure 2. The samples were returned to our laboratory
for review by the project engineer and testing.
SUBSURFACE CONDITIONS
A graphic log of the subsurface conditions encountered at the site is shown on Figure 2. The
subsoils encountered, below about 1/2 foot of topsoil, consisted of stiff to very stiff, sandy clayey
silt underlain at a depth of about 24 feet by relatively dense, clayey sandy basalt gravel and
cobbles with probable boulders down to the drilled depth of 31 feet.
Laboratory testing performed on samples obtained from the boring included natural moisture
content and density, and percent finer than sand size gradation analyses. Results of swell -
consolidation testing performed on relatively undisturbed drive samples, presented on Figures 3
and 4, indicate low to moderate compressibility under conditions of loading and wetting. The
samples showed a nil to low collapse potential when wetted under a constant 1,000 psf
surcharge. The laboratory testing is summarized in Table 1.
No free water was encountered in the boring at the time of drilling and the subsoils were slightly
moist.
Kumar & Associates, Inc. ® Project No. 20-7-256
-3 -
FOUNDATION BEARING CONDITIONS
The silt soils encountered in the boring have low density and generally a moderate settlement
potential, especially when wetted. Lightly loaded spread footings bearing on these soils can be
used for foundation support of the residence with some risk of settlement and building distress,
primarily if the bearing soils become wetted and precautions should be taken to prevent wetting.
Sources of wetting include excessive irrigation near the foundation, poor surface drainage
adjacent to foundation walls and utility line leaks. Sub -excavation and replacement of a depth
(typically 3 or 4 feet) of the natural soils below footing areas as compacted structural fill or
extending the foundation bearing down to the relatively dense, coarse granular soils, such as by
drilled or helical piers, would provide a relatively low risk of foundation settlement.
Provided below are recommendations for spread footings bearing on the natural soils. If
recommendations for bearing the footings on structural fill or a deep foundation system are
desired, we should be contacted.
DESIGN RECOMMENDATIONS
FOUNDATIONS
Considering the subsurface conditions encountered in the exploratory boring and the nature of
the proposed construction, the building can be founded with spread footings bearing on the
natural fine-grained soils with some risk of settlement. Precautions should be taken to prevent
wetting of the bearing soils.
The design and construction criteria presented below should be observed for a spread footing
foundation system.
1) Footings placed on the undisturbed natural soils should be designed for an
allowable bearing pressure of 1,200 psf. Based on experience, we expect
settlement of footings designed and constructed as discussed in this section will
be about 1 inch or less. There could be some additional settlement if the bearing
soils were to become wetted. The magnitude of the additional settlement would
depend on the depth and extent of the wetting but may be on the order of to
1 inch.
Kumar & Associates, Inc. ® Project No. 20.7-256
-4
2) The footings should have a minimum width of 24 inches.
3) Exterior footings and footings beneath unheated areas should be provided with
adequate soil cover above their bearing elevation for frost protection. Placement
of foundations at least 36 inches below exterior grade is typically used in this
area.
4) Continuous foundation walls should be heavily reinforced top and bottom to span
local anomalies and better withstand the effects of some differential settlement
such as by assuming an unsupported length of at least 14 feet. Foundation walls
acting as retaining structures should also be designed to resist a lateral earth
pressure corresponding to an equivalent fluid unit weight of at least 50 pcf.
5) All existing fill, topsoil and any loose or disturbed soils should be removed and
the footing bearing level extended down to the firm natural soils. The exposed
soils in footing area should then be moistened and compacted.
6) A representative of the geotechnical engineer should observe all footing
excavations prior to concrete placement to evaluate bearing conditions.
FLOOR SLABS
The natural on-site soils, exclusive of topsoil, are suitable to support lightly loaded slab -on -grade
construction with a risk of settlement if the slab subgrade were to become wetted as discussed
above in the "Foundation Bearing Conditions" section of this report. To reduce the effects of
some differential movement, floor slabs should be separated from all bearing walls and columns
with expansion joints which allow unrestrained vertical movement. Floor slab control joints
should be used to reduce damage due to shrinkage cracking. The requirements for joint spacing
and slab reinforcement should be established by the designer based on experience and the
intended slab use. A minimum 4 inch layer of sand and gravel base course should be placed
beneath the garage slab for support and to facilitate drainage. This material should consist of
minus 2 -inch aggregate with at least 50% retained on the No. 4 sieve and less than 12% passing
the No. 200 sieve.
All fill materials for support of floor slabs should be compacted to at least 95% of maximum
standard Proctor density at a moisture content near optimum. Required fill can consist of the on-
site soils devoid of vegetation, topsoil and oversized rocks.
Kumar & Associates, Inc. ® Project No. 20.7.256
-5
SURFACE DRAINAGE
Providing proper grading and drainage around the building will be critical to limiting subsurface
wetting and adequate performance of the structure. A perimeter foundation drain around shallow
(less than 4 feet deep) crawlspace areas should not be needed with adequate compaction of
foundation backfill and positive surface drainage away from foundation walls. The following
drainage precautions should be observed during construction and maintained at all times after the
residence has been completed:
1) Inundation of the foundation excavations and underslab areas should be avoided
during construction.
2) Exterior backfill should be adjusted to near optimum moisture and compacted to
at least 95% of the maximum standard Proctor density in pavement and slab areas
and to at least 90% of the maximum standard Proctor density in landscape areas.
3) The ground surface surrounding the exterior of the building should be sloped to
drain away from the foundation in all directions. We recommend a minimum
slope of 12 inches in the first 10 feet in unpaved areas and a minimum slope of 3
inches in the first 10 feet in paved areas.
4) Roof downspouts and drains should discharge well beyond the limits of all
backfill.
5) Landscaping which requires regular heavy irrigation, such as sod, and lawn
sprinkler heads should be located at least 10 feet from foundation walls.
LIMITATIONS
This study has been conducted in accordance with generally accepted geotechnical engineering
principles and practices in this area at this time. We make no warranty either express or implied.
The conclusions and recommendations submitted in this report are based upon the data obtained
from the exploratory boring drilled at the location indicated on Figure 1, the proposed type of
construction and our experience in the area. Our services do not include determining the
presence, prevention or possibility of mold or other biological contaminants (MOBC) developing
in the future. If the client is concerned about MOBC, then a professional in this special field of
practice should be consulted. Our findings include extrapolation of the subsurface conditions
Kumar & Associates, Inc. ® Project No. 20.7.256
6
identified at the exploratory boring and variations in the subsurface conditions may not become
evident until excavation is performed. If conditions encountered during construction appear
different from those described in this report, we should be notified so that re-evaluation of the
recommendations may be made.
This report has been prepared for the exclusive use by our client for design purposes. We are not
responsible for technical interpretations by others of our information. As the project evolves, we
should provide continued consultation and field services during construction to review and
monitor the implementation of our recommendations, and to verify that the recommendations
have been appropriately interpreted. Significant design changes may require additional analysis
or modifications to the recommendations presented herein. We recommend on-site observation
of excavations and foundation bearing strata and testing of structural fill by a representative of
the geotechnical engineer.
Respectfully Submitted,
Kumar & Associates, Inc.
James H. Parsons, E.I.
Reviewed by:
David A. You
JHP/kac
Kumar & Associates, Inc.
Project No. 20.7-256
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20-7-256
Kumar & Associates
LOCATION OF EXPLORATORY BORING
Fig. 1
w
w
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w
w
- 0
BORING 1
/1 26/12
12/12
//1 WC=3.7
5 DD=99
/ / 17/12
/ WC=3.9
DD=90
J —200=88
10 ! 13/12
WC=5.3
DD=91
15 //— 36/12
J WC=8.8
DD=106
20 26/12
] WC=5.6
DD=103
25
99/12
a
30 50/2
— 35
LEGEND
iAsa
7
b•
;
TOPSOIL: SANDY SILT, ORGANIC, SLIGHTLY MOIST, LIGHT BROWN.
SILT (ML): SANDY CLAYEY, STIFF TO VERY STIFF, SLIGHTLY MOIST,
LIGHT BROWN TO TAN.
BASALT GRAVEL AND COBBLES (GC): PROBABLE BOULDERS, SANDY,
CLAYEY, DENSE, SLIGHTLY MOIST, TAN.
DRIVE SAMPLE, 2—INCH I.D. CALIFORNIA LINER SAMPLE.
DRIVE SAMPLE, 1 3/8—INCH I.D. SPLIT SPOON STANDARD
PENETRATION TEST.
26/12 DRIVE SAMPLE BLOW COUNT. INDICATES THAT 26 BLOWS OF
A 140—POUND HAMMER FALLING 30 INCHES WERE REQUIRED
TO DRIVE THE SAMPLER 12 INCHES.
NOTES
1 THE EXPLORATORY BORING WAS DRILLED ON MAY 6, 2020 WITH A
4—INCH DIAMETER CONTINUOUS FLIGHT POWER AUGER.
2. THE LOCATION OF THE EXPLORATORY BORING WAS MEASURED
APPROXIMATELY BY TAPING FROM FEATURES SHOWN ON THE SITE
PLAN PROVIDED.
3. THE ELEVATION OF THE EXPLORATORY BORING WAS NOT
MEASURED AND THE LOG OF THE EXPLORATORY BORING IS
PLOTTED TO DEPTH.
4. THE EXPLORATORY BORING LOCATION SHOULD BE CONSIDERED
ACCURATE ONLY TO THE DEGREE IMPLIED BY THE METHOD USED.
5. THE LINES BETWEEN MATERIALS SHOWN ON THE EXPLORATORY
BORING LOG REPRESENT THE APPROXIMATE BOUNDARIES BETWEEN
MATERIAL TYPES AND THE TRANSITIONS MAY BE GRADUAL.
6. GROUNDWATER WAS NOT ENCOUNTERED IN THE BORING AT THE
TIME OF DRILLING. FLUCTUATIONS IN GROUNDWATER LEVEL MAY
CHANGE WITH TIME.
7. LABORATORY TEST RESULTS:
WC = WATER CONTENT (%) (ASTM D 2216);
DD = DRY DENSITY (pcf) (ASTM D 2216);
—200 = PERCENTAGE PASSING NO. 200 SIEVE (ASTM D 1140).
20-7-256
Kumar & Associates
LOG OF EXPLORATORY BORING
Fig. 2
a
2
a
E"
Is
1
.. 0
CONSOLIDATION - SWELL
—1
—2
—3
—4
SAMPLE OF: Sandy Clayey and Silt
FROM: Boring 1 0 4'
WC = 3.7 %, DD = 99 pcf
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peaardane..Nh MflA D-479&
ADDITIONAL COMPRESSION
UNDER CONSTANT PRESSURE
DUE TO WETTING
1.0 APPLIED PRESSURE — KSF 10 100
20-7-256
Kumar & Associates
SWELL—CONSOLIDATION TEST RESULTS
Fig. 3
CONSOLIDATION - SWELL
1
0
—1
— 2
— 3
— 4
— 5
CONSOLIDATION - SWELL (%)
I I
W N O
SAMPLE OF: Sandy Clayey Silt
FROM: Boring 1 ® 10'
WC = 5.3 %. DD = 91 pcf
ADDITIONAL COMPRESSION
f� UNDER CONSTANT PRESSURE
DUE TO WETTING
1.0 APPLIED PRESSURE - KSF 10 100
SAMPLE OF: Sandy Clayey Silt
FROM: Boring 1 ® 20'
WC = 5.6 %, DD = 103 pcf
Th... telt mull, opply only to the
.ompin teen& the le.Wry ,.pori
.hoe not be r.IVodUCM..xcep! In
full wpneul 11re edlt.n opprorol of
Humor and H.4Cio1a, Inn- Vne0
Con..lIQotien !epilog perlorm.d In
occurdontp wkh RSibI D-4540.
NO MOVEMENT UPON
WETTING
1.0 APPLIED PRESSURE - KSF 10 100
20-7-256
Kumar & Associates
SWELL—CONSOLIDATION TEST RESULTS
Fig. 4
K+A
Kumar & Associates, Inc.®
GeatechnIcal and MaIndals Engineers
end Environmental Soeniists
TABLE 1
SUMMARY OF LABORATORY TEST RESULTS
Pro iect No. 20-7-256
SAMPLE LOCATION
NATURAL
MOISTURE
CONTENT
I%)
NATURAL
DRY
DENSITY
(ncf)
GRADATION
PERCENT
PASSING NO.
200 SIEVE
ATTERBERG LIMITS
UNCONFINED
COMPRESSIVE
STRENGTH
(a$f)
SOIL TYPE
BORING
DEPTH
(ft)
GRAVEL
(i)
SAND
(i)
LIQUID LIMITINDEX
(i) _
PLASTIC
(i)
1
4
3.7
99
Sandy Clayey Silt
7
3.9
90
88
Sandy Clayey Silt
10
5.3
91
Sandy Clayey Silt
15
8.8
106
Sandy Clayey Silt
20
5.6
103
Sandy Clayey Silt