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Structural
Geotechnical
ROCKY MOUNTAIN GROUP
Materials Testing
Forensic
Civil/Planning
EMPLOYEE OWNED
SUBSURFACE SOIL INVESTIGATION
2198 CR 17
Brighton
PREPARED FOR:
Innotech Machining, Inc.
6125 West 59th Avenue, Suite E
Arvada, CO 80003
JOB NO. 173889
October 10, 2020
Respectfully Submitted,
RMG — Rocky Mountain Group
Dale W. Guillen, P.E.
Senior Engineer
Southern Office:
Colorado Springs, CO 80918
719.548.0600
Central Office:
Englewood, CO 80112
3 03.68 8.9475
Northern Office:
Evans, CO 80620
970.330.1071
www.rmgengineers.com
Fort Collins: 970.616.4364
Monument: 719.488.2145
Woodland Park: 719.687.6077
2198 17
Brighton
Scope of Investigation
RIVIG — Rocky Mountain Group drilled three test borings at the above -referenced address on September
10t. A Site Vicinity Map and Test Boring Location Plan are presented in Figures 1 and 2, respectively.
p
our findings, conclusions and recommendations are provided in this report.
We understand that the existing single family residence resides on the current property and that a new
structure is being built. The location of this new structure being built is located behind the existing
garage/shop and it will be attached to the existing garage/shop.
This report presents geotechnical engineering recommendations for design and construction of
residential foundations. The following is excluded from the scope of this report including but not limited
to geologic, natural and environmental hazards such as landslides, unstable slopes, seismicity, snow
avalanches, water flooding, corrosive soils, erosion, radon, wild fire protection, hazardous waste and
natural resources.
Subsurface Materials
The subsurface materials encountered in the test borings generally consisted of medium stiff to very stiff
sandy clay that extends to a depth of 12ft and sits on top of firm to medium hard claystone/bedrock that
extends to the 20 -foot termination depths of the test borings. Additional descriptions and the interpreted
distribution (approximate depths) of the subsurface materials are presented in the Test Boring Logs.
Groundwater was not encountered in the test borings at the time of drilling. When checked one day
subsequent to drilling, groundwater was encountered in all 3 bores at depths ranging between 17.5 and
18.5 feet below existing grade. Fluctuations in groundwater and subsurface moisture conditions may
occur due to variations in rainfall and other factors not readily apparent at this time. Development of the
property and ad] acent properties may also affect groundwater levels.
The Test Boring Logs, an Explanation of the Test Boring Logs and a Summary of Laboratory Test
Results are presented in Figures 3 through 5. Soil Classification Data and Atterberg Limits are
presented in Figure 6. Swell/Consolidation Test Results are presented in Figures 7 and 8.
Geotechnical Considerations
Soft/loose and dry soils were not encountered at anticipated foundation bearing levels. If soft/loose or
dry soils are encountered in the excavation, they will require additional compaction to achieve the
allowable bearing pressures indicated in this report. We recommend reconditioning the soils beneath the
foundation components prior to constructing the foundation by scarifying the top 12", moisture
conditioning and compacting the soils. Please reference the Structural Fill section below for compaction
recommendations. The use of track -mounted excavation equipment or other low -ground -pressure
equipment is recommended to reduce the likelihood of loss of stability duringexcavation.
Foundation Recommendations
A spread footing foundation supported on the properly reconditioned on -site sand soils is suitable for the
proposed structure. A maximum allowable bearing pressure of 2000 psf with a no minimum dead load
requirement may be used for design. The foundation design should be prepared by a qualified Colorado
Registered Professional Engineer using the recommendations presented in this report. This foundation
RMG — Rocky Mountain Group 2 RMG Job No. 173889
155 Palmer Dr
LOT 6, Fairway Estates
Fort Collins, Colorado
system should be designed to span a minimum of 10 feet under the design loads. The bottoms of
exterior foundations should be at least 30 inches below finished grade for frost protection.
Open Excavation Observation
During construction, foundation excavations should be observed by RMG prior to placing structural fill,
forms, or concrete to verify the foundation bearing conditions for each structure. Based on the
conditions observed in the foundation excavation, the recommendations made at the time of construction
may vary from those contained herein. In the case of differences, the Open Excavation Observation
report shall be considered to be the governing document. The recommendations presented herein are
intended only as preliminary guidelines to be used for interpreting the subsurface soil conditions
exposed in the excavation and determining the final recommendations for foundation construction.
Soil Test Borings
The soil/rock classifications shown on the logs are based upon the engineer's classification of samples.
Lines shown on the logs represent the approximate boundary between subsurface materials, and the
actual transition may be gradual and vary across the site.
Interior Partitions
Interior non-bearing partitions and attached furnishings (e.g., cabinets, shower stalls, etc.) on concrete
slabs should be constructed with a void so that they do not transmit floor slab movement to the roof or
overlying floor. A void of at least 1-1/2 inches is recommended beneath non-bearing partitions. Doors
should be provided with at least a 1 inch gap at floor level. Voids and gaps may require reconstruction
over the life of the structure to re-establish the void due to vertical slab movement.
Surface Grading and Drainage
The ground surface should be sloped from the building with a minimum gradient of 10 percent for the
first 10 feet. This is equivalent to 12 inches of fail across this 10 -foot zone. If a 10 -foot zone is not
possible on the upslope side of the structure, then a well-defined swale should be created a minimum 5
feet from the foundation and sloped parallel with the wall with a minimum slope of 2 percent to
intercept the surface water and transport it around and away from the structure. Roof drains should
extend across backfill zones and landscaped areas to a region that is graded to direct flow away from the
structure. Homeowners should maintain the surface grading and drainage recommended in this report to
help prevent water from being directed toward and/or ponding near the foundations.
Landscaping should be selected to reduce irrigation requirements. Plants used close to foundation walls
should be limited to those with low moisture requirements; and irrigated grass should not be located
within 5 feet of the foundation. To help control weed growth, geotextiles should be used below
landscaped areas adjacent to foundations. Impervious plastic membranes are not recommended.
Irrigation devices should not be placed within 5 feet of the foundation. Irrigation should be limited to the
amount sufficient to maintain vegetation. Application of more water will increase the likelihood of slab
and foundation movements.
RMG — Rocky Mountain Group 2 RMG Job No. 175006
155 Palmer Dr
LOT 6, Fairway Estates
Fort Collins, Colorado
The recommendations listed in this report are intended to address normal surface drainage conditions,
assuming the presence of groundcover (established vegetation, paved surfaces, and/or structures)
throughout the regions upslope from this structure. However, groundcover may not be present due to a
variety of factors (ongoing construction/development, wildfires, etc.). During periods when
groundcover is not present in the "upslopen regions, higher than normal surface drainage conditions may
occur, resulting in perched water tables, excess runoff, flash floods, etc. In these cases, the surface
drainage recommendations presented herein(even if properly maintained) may not mitigate all
groundwater problems or moisture intrusion into the structure. We recommend that the site plan be
prepared with consideration of increased runoff during periods when groundcover is not present on the
upsiope areas.
Perimeter Drain
A subsurface perimeter drain is recommended around portions of the structure which will have habitable
or storage space located below the finished ground surface. This includes crawispace areas but not the
walkout trench, if applicable.
The perimeter drain can be installed as an interior (if a minimum of six inches of free draining aggregate
is placed beneath the slab) or exterior perimeter drain system. The perforated drainage pipe should be
installed so the top of the pipe is not above the top of the footing and should be surrounded by material
to reduce the infiltration of silt into the drainage pipe. The pipe should be installed in one of the
following manners:
1) The pipe may be installed as level as possible as long as the pipe is placed in a minimum of six inches
of gravel or crushed stone and exits into a sump pit with mechanical means to remove the water.
Or
2) The pipe may be installed as a gravity system with a minimum 1/8 inch fall per 1 foot length
surrounded by a minimum six inches of gravel or crushed stone that either daylights to allow free flow
drainage or exits into a sump pit with mechanical means to remove the water.
A subsurface perimeter drain is designed to intercept some types of subsurface moisture and not others.
Therefore, the drain could operate properly and not mitigate all moisture problems relating to foundation
performance or moisture intrusion into the basement area.
Concrete
Sulfate testing was performed on selected samples based on ASTM C1580. Test results showed 0.47%
by weight, indicating the soils present Class 2 med to high) sulfate exposure. Based on these results
Type V cement or equivalent mixture according to AC1 201.2R-10 is suggested for concrete in contact
with the subsurface materials. Cement type shall be designed and approved by a licensed Colorado
Professional Engineer and Foundation Designer. Calcium chloride should not be used for the onsite
soils. The concrete should not be placed on frozen ground. If placed during periods of cold temperatures,
the concrete should be kept from freezing. This may require covering the concrete with insulated
blankets and heating. Concrete work should be completed in accordance with the latest applicable
guidelines and standards published by ACI.
RMG — Rocky Mountain Group 3 RMG Job No. 175006
155 Palmer Dr
LOT 6, Fairway Estates
Fort Collins, Colorado
Exterior Backfill
Backfill should be placed in loose lifts not exceeding 8 to 12 inches, moisture conditioned to facilitate
compaction (usually within 2 percent of the optimum moisture content) and compacted to 90 percent of
the maximum dry density as determined by the Standard Proctor test, ASTM D-698 on exterior sides of
walls in landscaped areas. In areas where backfill supports pavement and concrete flatwork, the
materials should be compacted to 95 percent of the maximum dry density.
Fill placed on slopes should be benched into the slope. Maximum bench heights should not exceed 4
feet, and bench widths should be wide enough to accommodate compaction equipment.
The appropriate government/utility specifications should be used for fill placed in utility trenches. If
material is imported for backfill, the material should be approved by the Geotechnical Engineer prior to
hauling it to the site.
The backfill should not be placed on frozen subgrade or allowed to freeze during moisture conditioning
and placement. Backfill should be compacted by mechanical means, and foundation walls should be
braced during backfilling and compaction.
Structural Fill
Areas to receive structural fill should have topsoil, organic material, or debris removed. The upper 6
inches of the exposed surface soils should be scarified and moisture conditioned to facilitate compaction
(usually within 2 percent of the optimum moisture content) and compacted to a minimum of 95 percent
of the maximum dry density as determined by the Standard Proctor test (ASTM D-698).
Structural fill placed on slopes should be benched into the slope. Maximum bench heights should not
exceed 4 feet, and bench widths should be wide enough to accommodate compaction equipment.
Structural fill shall consist of granular, non -expansive material, and it should be placed in loose lifts not
exceeding 8 to 12 inches, moisture conditioned to facilitate compaction (usually within 2 percent of the
optimum moisture content) and compacted to a minimum of 95 percent of the maximum dry density as
determined by the Standard Proctor test, ASTM D-698. The materials should be compacted by
mechanical means.
Materials used for structural fill should be approved by RMG prior to use. Structural fill should not be
placed on frozen subgrade or allowed to freeze during moisture conditioning and placement.
To verify the condition of the compacted soils, density tests should be performed during placement. The
first density tests should be conducted when 24 inches of fill have been placed.
Foundation Configuration Remarks
The configuration of the foundation system is critical to its performance. The position of foundation
windows, jogs, steps and the relative elevation of adjacent and opposite walls can affect foundation
performance. The nature of residential foundation construction does not allow for control of these
conditions by the Foundation Design Engineer. Improper placement of the above can result in
RMG — Rocky Mountain Group
4 RMG Job No. 175006
155 Palmer Dr
LOT 6, Fairway Estates
Fort Collins, Colorado
differential and lateral foundation movement not anticipated by the Geotechnical Engineer. The
Foundation Design Engineer should be contacted regarding the foundation configuration.
General Remarks
The recommendations provided in this report are based upon the subsurface conditions encountered in
the test borings, anticipated foundation loads, and accepted engineering procedures. The
recommendations are intended to reduce differential movement. It must be recognized that the
foundation will undergo some movement on all soil types. Concrete floor slabs will likely move
vertically. The recommendations for isolating floor slabs from columns, walls, partitions or other
structural components should be implemented to mitigate potential damage to the structure. Subsequent
owners should be provided a copy of this report. The recommendations are based on accepted local
engineering practice and are intended for individuals familiar with local construction practices and
standards.
RMG does not assure the existence of and/or the compliance with the above recommendations. This is
the responsibility of the client referenced on the first page. RMG provided recommendations only and
does not supervise, direct or control the implementation of the recommendations.
RMG — Rocky Mountain Group 5 RMG Job No. 175006
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VICINITY MAP
2198 WELD COUNTY ROAD 17
BRIGHTON, COLORADO
CLIENT
INNOTECH MACHINING, INC.
6125 W. 59TH AVENUE, SUITE E
ARVADA, CO. 80003
RMG PROJECT 4173889
DATE: 4 17 20
ROCKY MOUNTAIN
GROUP
1601 37th STREET
EVANS, CO. 80620
PHONE: (970) 330-1071
FAX: (970) 330-1252
0 50 100
SCALE: 1" = 100'
BORE LOCATION
PLAN
2198 WELD COUNTY ROAD 17
BRIGHTON, COLORADO
CLIENT .
I NNCTECH MACHINING, INC.
6125 W. 59TH AVENUE, SUITE E
ARVADA, CO. 80003
RMG PROJECT #173889
DATE: 10/12/20
ROCKY MOUNTAIN
GROUP
1601 37th STREET
EVANS, 00. 80620
PHONE: (970) 330-1071
FAX: (970) 330-1252
TEST BORING: 81
DATE DRILLED:
9110/20
REMARKS:
@ dry'
9/11/20
_,w
00
2
u)
oJ-
Q
w
WATER CONTENT %
TEST BORING: B2
DATE DRILLED:
9!10!20
REMARKS:
GROUNDWATER (a� dry'
9/11/20
_I
°°
�
co
c0
a
Q
coGROUNDWATER
WATER CONTENT °/y/
BLOWS PER
BLOWS PER I
EF'TI
PTI
CLAY,
brown
medium
silty
to
grey, orange,
stiff to very stiff,
and
dry
white,
5
V
%
A
16
10
41
45
-
16.1
157
17.7
16.9
CLAY,
brown
dry
silty
with
white
streaks,
stiff,
5
/
�A
A
9
24
43
50/10"
10.1
19.1
18.'
18
10
10
CLAYSTONE
brown,
medium
orange
hard,
dry
and
grey,
firm to
15
CLAYSTONE
brown, orange and grey, firm, dry
15
�
20
20
A
L
�
Architectural
Structural
Fcrcnsics
ROCKY MOUNTAIN GROUP
Colorado Springs- (Corporate Office)
2910 Austin Bluffs Parkway
Colorado Spings. CO80918
(719) E48-0600
SOUTHERN COLORADO. DENVER METRO, NORTHERN COLORADO
Gcotcchnical
Matcrials Testing
Civil Planning
TEST BORING
LOGS
JOB No. 173889
FIGURE No. 3
DATE Oct/06/2020
6
I
SOILS DESCRIPTION
SYM
11
XX
CLAYSTN E
SILTY CLAY
UNLESS NOTED OTHERWISE, ALL LABORATORY
TESTS PRESENTED HEREIN WERE PERFORMED BY:
RMG - ROCKY MOUNTAIN GROUP
1601 37TH ST.
EVANS, COLORADO
OLS AND NOTES
STANDARD PENETRATION TEST - MADE BY DRIVING A SPLIT -BARREL SAMPLER INTO
THE SOIL BY DROPPING A 140 LB. HAMMER 30", IN GENERAL ACCORDANCE WITH ASTM
D-1586. NUMBER INDICATES NUMBER OF HAMMER BLOWS PER FOOT (UNLESS
OTHERWISE INDICATED).
UNDISTURBED CALIFORNIA SAMPLE - MADE BY DRIVING A RING -LINED SAMPLER INTO
THE SOIL BY DROPPING A 140 LB. !HAMMER 30", IN GENERAL ACCORDANCE WITH ASTM
D-3550. NUMBER INDICATES NUMBER OF HAMMER BLOWS PER FOOT (UNLESS
OTHERWISE INDICATED).
FREE WATER TABLE
DEPTH AT WHICH BORING CAVED
BULK DISTURBED BULK SAMPLE
.AUG AUGER "CUTTINGS"
TTINGS"
4 WATER CONTENT (%)
Architocturd
Structural
Forensics
ROCKY MOMOUNTAIN 0 ROU P
Colorado SprJngs• (Corporate °ff it
2910 Austin Bluffs Parkway
Cdcracb Spings, CO 8O918
(719) 548-0600
SOUTHERN COLORADO, DENIER METRO, NORTHERN COLORADO
GcotechnicI
Materials Tcsting
Civil, Planning
v
J‘k, _
EXPLANATION OF
TEST BORING LOGS
v
JOB No. 173889
FIGURE No. 4
DATE Oct/06/2020
2
f
Test Boring
No.
Depth
P
Water
Content
4
(/gym
Dense
(pcf
Liquid
Limit
Plasticity
Index
No.4
Retained
Sieve
Passing
Passing
200 Sieve
No.
%
Collapse
Swell/
Load
(psf)
B1
4.0
16.1
106.8
B1
9.0
15.7
112.7
45
33
0.2
96.1
0.8
1000
B1
14.0
17.7
111.3
2.3
1000
B1
19.0
16.9
112.8
B2
4.0
10.6
105.0
40
25
76.6
- 0.3
1000
B2
9.0
19.6
103.6
B2
14.0
18.1
110.2
B2
19.0
18A
110.0
t
i
Arehitoetural
Structural
Forensics
ROCKY MOUNTAIN GROUP
Colorado Sprkigs• (Corporate Offb j
2910 Austin Bluffs Parkway
Cdcratlo Spings, CC 80918
(719) 518-0600
SOUTHERN COLORADO, DENIER METRO, NORTHERN COLORADO
Gcotochnieal
Materials Testing
Civil, Planning
v
SUMMARY OF
LABORATORY TEST
RESULTS
V
JOB No. 173889
FIGURE No. 5
PAGE 1 OF 1
DATE Oct/06/2020
J
100
90
H80
2
7
ED60
O
z
X50
a
-40
z
W
L30
W
a
20
10
0
U.S. SIEVE OPENING IN INCHES U.S. SIEVE NUMBERS
3 1.5 1 3/4 1/23/8 4 10 20 40 100 200
HYDROMETER
100 10 1
GRAIN SIZE IN MILLIMETERS
0.1
0.01
0.001
COBBLES
ORAI�EL
SAND
SILT OR
CLAY
coarse
fine
coarse
medium
fine
Test Boring
Depth (ft)
Classification
LL
PL
PI
B1 9.0
LEAN CLAY( L)
45
12
33
I
B2 4.0
LEAN CLAY with SAND(CL)
40
15
25
Test Boring Depth (ft)
%Gravel
ravel
%Sand
%Silt
%Clay
B1 9.0
0.2
3.7
96.1
I
B2 4.0
0.0
23.4
76.6
Architcctural
Structural
Fcrcnsics
ROCKY MOUNTAIN GROUP
ARCHITECTS
RMG
EN (3IN,ILEHS
Cdcricic Springs (Ccrperote Office)
2910 Austin Bluffs Parkway
Cdcrada Spings, CO 80918
(719) E48-0600
SOUTHERN COLORADO, DENVER METRO, NORTHERN COLORADO
GcbtcchnicI
Matcrials Tcsting
Civil, Planning
-b\fr
SOIL CLASSIFICATION
DATA
JOB No. 173889
FIGURE No. 6
DATE Oct/06/2020
2
z
0
z
C
O
X
W
z
0
C1)
Co
W
O
C
z
0
z
C
0
>C
w
z
0
COMPRESS
COMPRESS
- 1.0
- 2.0
- 3.0
-4.0
-5.0
- 6.0
100
- 1.0
- 2.0
- 3.0
-4.0
-5.0
- 6.0
100
S
APPLIE 1 F.EI RE - PSF
PROJECT: 2198 CR 17 brighton
SAMPLE DESCRIPTION: Clay
NOTE: SAMPLE WAS INUNDATED WITH WATER AT 1000 PSF
SAMPLE LOCATION: B1 @ 9 FT
NATURAL DRY UNIT WEIGHT: 114.0 PCF
NATURAL MOISTURE CONTENT: 15.2%
PERCENT SWELL/COMPRESSION: 0.8
10,000
APPLIED P1RE S RE - PSF
PROJECT: 2198 CR 17 brighton
SAMPLE DESCRIPTION: Claystone
NOTE: SAMPLE WAS INUNDATED WITH WATER AT 1000 PSF
Architectural
Structural
Fcrcnsics
ROCKY MOUNTAIN GROUP
Colorado Springs- (Corporate Office)
2910 Austin Bluffs Parkway
Colorado Spings. CO80918
(719) E18-0600
SOUTHERN COLORADO. DENVER METRO, NORTHERN COLORADO
Gcotcchnical
Matcrials Testing
Civil Planning
SAMPLE LOCATION: B1 @ 14 FT
NATURAL DRY UNIT WEIGHT: 91.1 PCF
NATURAL MOISTURE CONTENT: 16.4%
PERCENT SWELL/COMPRESSION: 2.3
SELL/CONSOLIDATION
TEST RESULTS
eals, _
V
10,000
JOB No. 173889
FIGURE No. 7
DATE Oct/06/2020
1%%N\
- 1.0
fig
z
O
z
C
O
W
z
O
COMPRESS
- 2.0
- 3.0
-4.0
-5.0
- 6.0
100
APPLIE DPIPTFli.LICSTU RE - PSF
PROJECT: 2198 CR 17 brighton
SAMPLE DESCRIPTION: Silty Clay
NOTE: SAMPLE WAS INUNDATED WITH WATER AT 1000 PSF
Architectural
Structural
Fcrcnsics
ROCKY MOMOUNTAIN G ROU P
Colorado Springs- (Corporate Office)
2910 Austin Bluffs Parkway
Colorado Spings. CO80918
(719) E18-0600
SOUTHERN COLORADO. DENVER METRO, NORTHERN COLORADO
Gcotcchnical
Matcrials Testing
Civil Planning
SAMPLE LOCATION: B2 @ 4 FT
NATURAL DRY UNIT WEIGHT: 98.9 PCF
NATURAL MOISTURE CONTENT: 10.1%
PERCENT SWELL/COMPRESSION: - 0.3
V
SELL/CONSOLIDATION
TEST RESULTS
eals, _
10,000
JOB No. 173889
FIGURE No. 8
DATE Oct/06/2020
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