HomeMy WebLinkAboutSoils Report 05.07.2018Engineering, Inc.
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GARFIELD
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CIVIL/GEOTECHNICAL
SOIL AND FOUNDATION INVESTIGATION
FOR THE
SHANNON GUEST HOUSE
6000 COUNTY ROAD 115 (AKA RED CANYON ROAD)
GLENWOOD SPRINGS
GARFIELD COUNTY, COLORADO
PROJECT NO. 18-3257
MAY 7, 2018
PREPARED FOR:
ABEL MONTANEZ 1179 HWY 133 #10
CARBONDALE, CO 81623
P.O. Box 724, Eagle, CO 81631 Tel (970) 390-0307 www.lkpengineering.com
1
TABLE OF CONTENTS
EXECUTIVE SUMMARY 2
SCOPE OF STUDY 2
SITE DESCRIPTION 2
PROPOSED CONSTRUCTION 3
FIELD INVESTIGATION 3
SUBSURFACE SOIL AND GROUNDWATER CONDITION 3
FOUNDATION RECOMMENDATIONS 4
SLAB CONSTRUCTION 5
RETAINING WALLS 5
UNDERDRAIN SYSTEM 6
SITE GRADING AND DRAINAGE 6
LAWN IRRIGATION 7
LIMITATION 7
FIGURES
LOCATION SKETCH DRAWING NO. 1
SUBSURFACE EXPLORATION LOGS .FIGURE NO's 1 - 3
SWELL/CONSOLIDATION TEST RESULTS FIGURE NO'S 4 - 5
GRAIN SIZE DISTRIBUTION FIGURE NO. 6
PERIMETER DRAIN FIGURE NO. 7
LKP Engineering, Inc. Project: 18-3257
2
EXECUTIVE SUMMARY
The proposed guest house should be supported
with conventional type spread footings, designed
for a maximum allowable soil bearing pressure
of 3000 psf and a minimum dead load of 1000
psf. They should construct the footings on the
undisturbed whitish, cemented, calcareous sandy
clay. See Foundation Recommendations.
SCOPE OF STUDY
This report presents the results of a subsurface Soil and Foundation Investigation for the
proposed Shannon Guest House to be constructed at 6000 County Road 115 (Aka Red Canyon
Road), Glenwood Springs, Garfield County, Colorado. The legal description of the property as
listed at the assessor's data site is Section 28, T6S, R88W, a parcel in Lot 15 and the SE1/4 of
Section 28, aka Lot 1, Simmons (Arnove) Exemption. The purpose of the subsurface soil and
foundation investigation was to determine the engineering characteristics of the foundation soil
and to provide recommendations for the foundation design, grading, and drainage. Geologic
hazard studies are outside of our scope of services.
SITE DESCRIPTION
Lot 1 is a 30.455 -acre parcel of land, on both sides of Red Canyon Road, at 6000 County
Road 115 (Aka Red Canyon Road), Glenwood Springs, Garfield County, Colorado. The
proposed building site for the proposed Guest House is located across the road from the existing
main house and above and about 80 feet north from the existing chicken coup. The topography
LKP Engineering, Inc. Project: 18-3257
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of the proposed building site is moderate. Drainage is to the south and southwest. Vegetation
within the proposed building site consisted of sage brush.
PROPOSED CONSTRUCTION
At the time of the soils and foundation investigation, building plans were not available
for the proposed guest. Based on our conversations, we understand that the proposed guest house
will be single story wood frame constriction over a crawl space. The test pits had been already
excavated by yourself, prior to our site visit. Loads are anticipated to be light, typical of
residential construction.
If the finalized plans differ significantly from the above understanding, we should be
notified to reevaluate the recommendations of this report.
FIELD INVESTIGATION
The field investigation, conducted on April 30, 2018 and May 7, 2018, consisted of
logging and sampling two test pits and the excavation cut on the back of the chicken coup.
Excavation of the test pits was done by you prior to our site visit. The test pits' locations are
shown on Drawing No. 1. We show the soil profile of the test pits on the Subsurface Exploration
Logs, Figure No's 1 through. Soil samples for laboratory soil analysis and observation were
taken at selected intervals.
SUBSURFACE SOIL AND GROUNDWATER CONDITION
The soil profiles encountered in the two test pits were fairly uniform. The soil exposed in
the excavation cut on the back of the chicken coup and about 50 feet south from test pit number
three was slightly different. Test Pit No. 1 had about one foot of topsoil over 1.5 feet of blocky
clay over two feet of reddish -brown calcareous clay over whitish, cemented sandy clay with
some basalt rocks to about 8 feet. At the bottom of the test pit there was a layer of whitish -
grayish, silty, gravelly sand. The excavation cut behind the chicken coup was used as test pit
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number two. The soil profile exposed in the cut consisted of about one foot of topsoil over five
feet of hard, reddish -brown clay over reddish -brown hard clay with cobble size basalt rocks. Test
Pit No. 3 was excavated on May 6 and we observed it on May 7, 2017. The soil profile observed
in Test Pit Number 3 was similar to the soil in test pit one and it consisted of about one foot of
topsoil over 2.5 feet of blocky clay over 2.5 feet of reddish -brown to brown calcareous clay over
whitish, cemented sandy clay with some basalt rocks to the maximum depth excavated of 8 feet.
Ground water was not encountered in either test pit. We sampled the soil in the test pit at random
intervals. The soil samples were brought to our laboratory for observation and analysis. They
were tested for natural dry density, natural moisture content, swell/consolidation, and sieve
analysis, as shown on the Swell/Consolidation Test Results, Figure No.'s 4 and 5, and the Grain -
Size Distribution, Figure No. 6.
FOUNDATION RECOMMENDATIONS
The on-site clayey soils showed low to high potential for expansion. The proposed guest
house should be supported with conventional type spread footings or pads and grade beams,
designed for a maximum allowable soil bearing pressure of 3000 psf and a minimum dead load
of 1000 psf. They should construct the footings on the undisturbed sandy, reddish -brown
calcareous clay or on the whitish cemented sandy clay.
We don't recommend constructing the guest house near the site of the new chicken coup
(across the road from the main house) where the hard clay with high potential for expansion was
encountered. If that site is selected additional testing with a drill rig will be required in order to
provided recommendations for the foundation design.
The undersigned engineer must observe the foundation excavation to verb that the soil
conditions are as anticipated from the two test pits. For a deep foundation system alternatives,
like straight shaft piers or micro piles, an additional soils and foundation with a drill rig will be
necessary.
Continuous foundation walls should be well reinforced, top and bottom, to span an
unsupported length of at least 10 feet. A minimum backfill cover as required by the local
building department should be provided for frost protection of the footing subsoils.
LKP Engineering, Inc. Project: 18-3257
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The foundation excavation should be free from excavation spoils, frost, organics and
standing water. Any overexcavation within the proposed foundation should be backfilled, in 8
inches loose, level lifts and compacted to 98% of the maximum dry density and within 2 percent
of the optimum moisture content as determined in a laboratory from a Standard Proctor test
(ASTM D-698). Structural fill, placed under footings, should be tested by a qualified
professional.
For any additional foundation alternatives, please contact our office.
SLAB CONSTRUCTION — CRAWL SPACE
The proposed structure will be a structural floor over crawl space. The crawl space must
be vented according to the local building code requirements.
RETAINING WALLS
Foundation walls retaining earth and retaining structures that are laterally supported
should be designed to resist an equivalent fluid density of 60 pcf for an "at -rest" condition.
Laterally unrestrained structures retaining the on-site earth should be designed to resist an
equivalent fluid density of 40 pcf for the "active" case.
Passive earth pressure of 360 psf can 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 friction of 0.45. Undisturbed soil or a structural, non -swelling fill compacted to
100 percent of the maximum dry density and within 2 percent of the optimum moisture content
shall be used to resist lateral loads at the sides of the footings.
The above design recommendations assume drained backfill conditions and a horizontal
backfill surface. Surcharge loading due to adjacent structures, weight of temporary stored
construction materials and equipment, inclined backfill and hydrostatic pressure due to undrained
backfill should be incorporated in the design. Every attempt should be made to prevent the
buildup of hydrostatic pressure behind the retaining wall.
LKP Engineering, Inc. Project: 18-3257
6
UNDERDRAIN SYSTEM
To reduce the risk of surface water infiltrating the foundation subsoil, installation of a
foundation perimeter drain is recommended (see Figure No. 7). The foundation perimeter drain
should consist of a 4 -inch diameter perforated pipe sloped to a suitable gravity outlet, or to a
sump pump location. The drain should slope at 1/4 inch per foot if flexible or at 1/8 of an inch if
rigid pipe is used. 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 be placed over
the moisture barrier and covered with a minimum of 6 inches of -3/4 inch free -draining granular
material. Geotextile (Mirafi 140N or equivalent) should be used to cover the free -draining gravel
to prevent siltation and clogging of the drain. The backfill above the drain should be granular
material to within 2 feet of the ground surface to prevent a buildup of hydrostatic pressure. The
top one foot of the backfill material should consist of a relatively impervious fill. The backfill
should be sloping away from the building.
SITE GRADING AND DRAINAGE
The following recommendations are general in nature. The site surrounding the building
structure should slope away from the building in all directions. A minimum of 12 inches in the
first 10 feet is recommended in unpaved areas, and three inches in the first 10 feet in paved areas.
The top of the granular foundation backfill should be covered with a minimum of one foot of
relatively impervious fill to reduce the potential of surface water infiltrating the foundation
subsoils. Exterior backfill should be compacted at or near the optimum moisture content to at
least 95% of the maximum standard Proctor density under pavement, sidewalk and patio areas
and to at least 90% of the maximum standard Proctor density under landscaped areas.
Mechanical methods of compaction should be used. Do not puddle the foundation excavation.
Surface water naturally draining toward the proposed building site should be diverted
around and away from it by means of drainage swales or other approved methods. The roof
drains and downspouts should extend and discharge beyond the limits of the backfill.
LKP Engineering, Inc. Project: 18-3257
7
LAWN IRRIGATION
It is not recommended to introduce excess water to the foundation soils by installing
sprinkler systems adjacent to the building. The installation of the sprinkler heads should insure
that the spray from the heads will not fall within 10 feet of foundation walls, porches or patio
slabs. 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 backhoe
was selected by Mr. Montanez, the general contractor, as the preferred method for the soil and
foundation investigation over a soil and foundation investigation with a drill rig. 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 Figure No. 1 and on assumptions
stated in the report. Soil conditions at other locations and depths may vary, which may not
become evident until the foundation excavation is completed. If soil or water conditions seem
different from those described in this report 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 report. There is no other warranty either expressed or implied.
This report has been prepared for the exclusive use of Abel Montanez, for the specific
application of the Shannon Guest House to be constructed in the area tested at 6000 County Road
115 (Aka Red Canyon Road), Glenwood Springs, Garfield County, Colorado.
Sincerely,
LKP ENGINEERING, INC.
Luiza Petrovska, PE
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LKP Engineering, Inc. Project: 18-3257
NOTE: THE LOCATION OF THE TEST PITS IS
APPROXIMATE IT IS NOT BASED ON A SURVEY
CIVIL/GEOTECHNICAL
(LKP Engineering, Inc.
}
P.O. Box 724, Eagle, CO 81631
Tel (970) 390-0307 www.lkpengineering.com
LOCATION SKETCH
6000 COUNTY ROAD 115
aka RED CANYON ROAD
GLENWOOD SPRINGS
GARFIELD COUNTY, COLORADO
PROJECT NO
18-3257
SCALE:
-1"=50'
DRAWING NO.:
1
DATE OBSERVED: April 30. 2018 Test Pit # 1
ELEVATION:
S
S
Y
A
DEPTH
M
M
DESCR/P770N OF MATERIAL
LABORATORY
REMARKS
FEET
B
P
AND SAMPLE LOCATION
TEST RESULTS
O
L
L
E
Topsoil
Brown, blocky Clay
Reddish-brown, calcareous
�•
.
Clay
DD= 97.6 pcf
❑
MC= 12.9%
5
i/Whitish,
cemented sandy Clay
.O :;
with some basalt rocks
'� ,
(gravel to cobble size)
—
?�
Whitish-grayish, silty, gravelly DD= 83.0 pcf MC=6.6%
._
i,
•
Sand at the bottom
Mc= 10.9 %
-200=6%
Bottom of Test Pit @ 8 feet
No Ground Water
Encountered
10
15
20
-
LEGEND:
❑ - 2-inch O.D. California Liner Sample
• - Bulk Sample
DD - Natural Dry Density (pcf)
MC - Natural Moisture Content (%)
-200 - Percent Passing No. 200 Sieve
LL - Liquid Limit
PI - Plasticity Index
GW - Ground water
PRO„ECT Na.:
18-3257
LKP ENGINEERING, INC.
SUBSURFACE EXPLORATION LOG
FIGURE NO.:
1
DATE OBSERVED: April 30, 2018 Test Pit # 2 - open excavation cut
ELEVATION: behind the chicken coup
DEPTH
FEET
s
Y
M
B
O
L
s
A
M
P
L
E
DESCRIPTION OF MATERIAL
AND SAMPLE LOCA 770N
LABORATORY
TEST RESULTS
REMARKS
itri
Topsoil, silty with fine roots
❑
Reddish brown, hard Clay
DD= 107.0 pcf
MC= 14 9
5
Reddish-brown, clay with
basalt rocks (cobble size)
Bottom of Cut ® 8 feet
No Ground Water
Encountered
10
15
20
LEGEND:
❑ - 2—inch O.D. California Liner Sample
■ — Bulk Sample
DD — Natural Dry Density (pcf)
MC — Natural Moisture Content (9)
—200 — Percent Passing No. 200 Sieve
LL — Liquid Limit
PI — Plasticity Index
GW — Ground water
LKP ENGINEERING, INC.
SUBSURFACE EXPLORATION LOG
PRO, ECT NO.:
18-3257
FlCURE NO.:
2
DATE OBSERVED: May 7, 2018 Test Pit # 3
ELEVATION:
DEPTH
FEET
S
Y
M
B
O
L
S
A
M
P
L
E
DESCRIPTION OF MATERIAL
AND SAMPLE LOCATION
LABORATORY
TEST RESULTS
REMARKS
Topsoil
,
Brown, blocky Clay
V 5
,�,
Reddish—brown, to brown,
calcareous Clay
1f'.
Whitish, cemented sandy Clay
with some basalt rocks
(gravel to cobble size)
Bottom of Test Pit 0 8 feet
No Ground Water
Encountered
10
15
20
LEGEND:
❑ - 2—inch 0.D. California Liner Sample
■ — Bulk Sample
DD — Natural Dry Density (pcf)
MC — Natural Moisture Content (9)
—200 — Percent Passing No. 200 Sieve
LL — Liquid Limit
PI — Plasticity Index
GW — Ground water
LKP ENGINEERING, INC.
SUBSURFACE EXPLORATION LOG
PRO..ECT NO.:
18-3257
FIGURE NO.:
3
3
2
1
0
— 1
0
y —2
—3
0)
W
— 4
3
2
1
0
— 1
— 4
LKP Engineering, Inc.
Swell — Consolidation Test Results
Aftircr Na:
18-3257
RpARr Na:
4
EXPANSION
CONSTANT
WHEN
PRESSURE
WETTED
OF
UNDER
1000
PSF
0.1 1 0 10 100
APPLIED PRESSURE — ksf
Sample of Reddish—whitish, calcareous sandy Clay from: Test Pit No. 1 at 4 feet
Natural Dry Unit Weight = 9Z 6 pcf
Natural Moisture Content = 12.9 percent
0.7.E SWELL AT 2.6 KSF
LKP Engineering, Inc.
Swell — Consolidation Test Results
Aftircr Na:
18-3257
RpARr Na:
4
0.1 1 0 10 100
APPLIED PRESSURE — ksf
Sample of Whitish, clayey Sand From: Test Pit 1 at 8 feet
Natural Dry Unit Weight = 83.0 pcf
Natural Moisture Content = 10.9 percent
LKP Engineering, Inc.
Swell — Consolidation Test Results
Aftircr Na:
18-3257
RpARr Na:
4
0
0)
k
W
of
3
2
1
0
—1
-4
LKP Engineering, Inc.
Swell — Consolidation Test Results
PROEM" Na:
18-3257
MORE :
5
1
- EXPANSION
CONSTANT
1 1 1 11__11
WI-rEN
PRESSURE
WETTED UNDER
OF 1000 PSF
1 1 1
0.1 1.0 10 100
APPLIED PRESSURE — ksf
Sample of Reddish—brown, hard Clay From: Bank cut behind chicken coup at 4 feet
Natural Dry Unit Weight = 107.0 pcf
Natural Moisture Con ten t = 14.0 percent
2.2X SWELL AT 8.5 KSF
LKP Engineering, Inc.
Swell — Consolidation Test Results
PROEM" Na:
18-3257
MORE :
5
•0u/ 86WO9u/6u3 d)17
NOl1nBIdlSIO 3Z/S-NIV2/O
o4
FROM: Test Pit No. 1 at 8 feet
U.& STANDARD SIEVE OPENING IN INCHES U.S STANDARD SIEVE NUMBERS HYDROMETER
Inn 6 4 3 2 1a 1 4.4v+ y. 3 4 6 810 14 16 20 3040 50 70 100 140 200
II
0 0 0 In* 0
Percent Finer by Weight
�i
`
i
1
1
1
1
Percent Coarser by Weight
N NI * � ccoo n 0 ooi
•
500 100 50 10 5 1 0 5 01 0 05 0.005 0.0011 UV
Gravel
Sand
Cobbles
coarse
fine
coarse mediumfine
Silt or Clay
Gravel: 9X Sand: 85Z Fines 6X
Moisture Content: 6.6X Description: Silty, gravelly, Sand
e
b FGD ZING
LOPE AWAY FROM BUILDING
OVER BACKFILL WITH A MINIMUM
OF ONE FOOT OF RELATIVELY
IMPERVIOUS SOIL
6
6 -
o-
0
GRANULAR FILL
ILTER FABRIC (MIRAFI
140N OR EQUIVALENT)
Dp.. •dam .. /�
o-. iQ
0� ` •
.0.,t1:;.\
Q/` '\ INUS 3/4 -INCH DIAMETER, COARSE,
CLEAN CRUSH ROCK
30 MIL MINIMUM THICKNESS,
PLASTIC LINER, GLUED TO TH
FOUNDATION WALL
-INCH DIAMETER PERFORATED PIPE SLOPED TO
A DAYLIGHT LOCATION AWAY FROM THE
FOUNDATION AT 1/4 -INCH PER FOOT FOR
FLEXIBLE AND 1/8 -INCH MINIMUM FOR RIGID PIPE
CIVIL/GEOTECHNICAL
Engineering, Inc.
P.O. Box 724, Eagle, CO 81631
Tel (970) 390-0307 www.lkpengineering.com
PERIMETER DRAIN
6000 COUNTY ROAD 115
aka RED CANYON ROAD
GLENWOOD SPRINGS
GARFIELD COUNTY, COLORADO
PROJECT NO.:
18-3257
SCALE:
N.T.S.
FIGURE NO.:
7