HomeMy WebLinkAboutObservation of Excavation 05.29.2020•
Kumar & Associates, UM.'
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.kumarusa.com
Office Locations: Denver (I -1Q), Parker, Colorado Springs, Fort Collins, Glenwood Springs, and Summit County, Colorado
May 29, 2020
Terry and Heidi Ruonavaara
160 Spring Ridge Drive
Glenwood Springs, Colorado 81601
thruonavaara cuinsn.com
Project No. 20-7-105
Subject: Observation of Excavation, Proposed Residence, Lot 59, Spring Ridge Reserve,
Hidden Valley Drive, Garfield County, Colorado
Terry and Heidi:
As requested, a representative of Kumar & Associates, Inc. observed the excavation at the
subject site on May 11, 2020 to evaluate the soils exposed for foundation support. The findings
of our observations and recommendations for the foundation design are presented in this report.
We previously conducted a subsoil study for design of foundations at the site and presented our
findings in a report dated January 23, 2020, Project No. 20-7-105.
The proposed residence is essentially the same as described in our previous report. Spread
footings sized for an allowable bearing pressure of 1,500 psf were designed for the building
support.
At the time of our visit to the site, the foundation excavation had been cut in one level from
1Y2 feet at the south end to 8 feet at the northeast corner below the adjacent ground surface. The
soils exposed in the bottom of the excavation were variable and consisted of fairly loose, sand
and silt in the south part and sandstone/siltstone bedrock in about the northern quarter of the
building footprint. Results of swell -consolidation testing performed on a sample of soil taken
from the south end of the site, shown on Figure 1, indicate the soils are moderately to highly
compressible under conditions of loading and wetting. The testing results are summarized in
Table 1. No free water was encountered in the excavation and the soils were slightly moist.
Based on the relatively low density and compressible soils, the natural soils should be removed
below footing areas and replaced compacted as recommended in our previous report. We
returned to the site on May 18 and 20 for density testing of the compacted subgrade with the
results presented in the attached Soil Compaction Reports. The laboratory Proctor compaction
test results are presented on Figures 2 and 2A. The field test results indicate compaction with
moisture content generally near optimum. The compaction level is somewhat variable probably
caused by the variable gradation (fine to coarse material) and typically in the 95 to 98% range.
The soil conditions exposed in the excavation are consistent with those previously encountered
on the site and after compaction, suitable for support of spread footings designed for the
Terry and Heidi Ruonavaara
May 29, 2020
Page 2
recommended allowable bearing pressure of 1,500 psf with the risk of differential settlement as
described in our previous report. Loose disturbed soils and rock in the footing areas should be
removed or moistened and compacted. Other recommendations presented in our previous report
which are applicable should also be observed.
The recommendations submitted in this letter are based on our observation of the soils exposed
within the foundation excavation and the previous subsurface exploration at the site. Variations
in the subsurface conditions below the excavation could increase the risk of foundation
movement. We should be advised of any variations encountered in the excavation conditions for
possible changes to recommendations contained in this letter. 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.
If you have any questions or need further assistance, please call our office.
Sincerely,
Kumar & Associates, Inc.
Steven L. Pawlak * P.I sn 15222
SLP/kac '��' �v/�izc..[�
Attachments: Figu S `r�� lidation Test Results
Figures aboratory Proctor Compaction and Particle Size Distribution
Table 1 — Summary of Laboratory Test Results
Soil Compaction Reports, 5-18-20 and 5-20-20.
Kumar & Associates, Inc. Project No. 20.7-105
4
3i
84
oz"
4
CONSOLIDATION - SWELL
2
0
— 2
— 4
— 6
— 8
— 10
— 12
— 14
SAMPLE OF: Sandy Silt
FROM: Southwest End
WC = 10.3 %. DD = 90 pcf
1b1 101 Mare o aint70 N.
.unG.. tend- mo .elf report
Mlt 0erpM
e01 . roduc, p! In
futl, .11heu. tlx .ril.n approval of
KAM* a.b M0ti010a, Inc. Swell
C4..o0tlolkn t..INW w.f0nrd in
accordance with ASTM O-1516.
ADDITIONAL COMPRESSION
UNDER CONSTANT PRESSURE
DUE TO WETTING
1.0 APPLIED PRESSURE — ICSF 10 100
20-7-105
Kumar & Associates
SWELL—CONSOLIDATION TEST RESULTS
Fig. 1
Dry density, pcf
122
120
118
116
114
112
Laboratory Proctor Compaction Test Report
t
T11.4%. 118.0..p
.op
Y
7.5 9 10.5 12 13.5 15 16.5
Water content, %
Test specification: ASTM D 698-12 Method B Standard
ZAV for
Sp.G. =
2.50
Elev/ Classification Nat.
Depth USCS AASHTO Moist.
Sp.G. LL PI
3/8 in.
No.200
SM A-.4(0) 20 3 0 47
TEST RESULTS MATERIAL DESCRIPTION
Maximum dry density = 118.0 pcf
Optimum moisture = 11.4 %
Sand and Silt
Project No. 20-7-105 Client: Terry & Heidi Ruonavaara
Project: Lot 59, Spring Ridge Reserve, Hidden Valley Drive, Garfield County,
Colorado
o Location: On Site Stockpile Sample Number: 108-20
Kumar & Associates, Inc.
Glenwood Springs, Colorado
Remarks:
See Figure 2A for classification results.
Figure 2
Tested By: KO
Checked By: SLP
Particle Size Distribution
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GRAIN
0 1
SIZE - mm.
0.01 0.001
% +3„
% Gravel
Coarse Fine_
%Sand
Coarse Medium Fine
%Fines
Silt j Clay
-
0 2
2 11 38
47
0
SIEVE PERCENT
SPEC.*
PASS?
SoII Description
SIZE FINER
PERCENT
(X=NO)
Sand and Silt
.375 100
#4 98
#8 96
Atterberg Limits
#16 94
#30 90
#50 80
PL= 17 LL= 20 PI= 3
Coefficients
#100
#200
62
47
D90= 0.6000 085= 0.4243 D60= 0.1368
D50= 0.0862 030= D15=
010= Cu— Cc=
Classification
USCS= SM AASHTO= A-4(0)
Remarks
See Figure 2 for standard Proctor compaction results.
(no specification provided)
Location: On Site Stockpile
Sample Number: 108-20 Date: 5/18/2020
Kumar & Associates, Inc.
Glenwood Springs, Colorado ,.
Client: Terry & Heidi Ruonavaara
Project: Lot 59, Spring Ridge Reserve, Hidden Valley Drive, Garfield
County, Colorado '
Project No: 20-7-105 Figure 2A
Tested By: KO
Checked By: SLP
Pro act Na. 20.7.105
SAMPLE LOCATION
NATURAL
MOISTURE
CONTENT
(%)
NATURAL
DRY
DENSITY
(Pcf)
GRADATION
PERCENT
PASSING NO.
200 SIEVE
ATTERBERG LIMITS
UNCONFINED
COMPRESSIVE
STRENGTH
{PSF)
SOIL OR
BEDROCK TYPE
BOTTOM OF EXCAVATION
5H7120
GRAVEL
(%)
SAND
(%)
LIQUID LIMB
(°Yo)
PLASTIC
INDEX
I%)
Southwest End
10.3
90
Sandy Silt
East Side Middle
3.1
104
20
Silty Sand with Rock
Fragments
Kumar AInC-"
GhniG5l (Ind Ma(nrE3
Frkjrf12Cr5
�nr1 Zr iraRmnr EaP SL101114its
TABLE 1
SUMMARY OF LABORATORY TEST RESULTS
{+A
l
Glenwood Spring.
5020 County Road 164
Glenwood Springs, CO 81601
Phone: 670-945.7988
PAWN it umsuu-.
CeotecMbal and Materia
and Envlronnie.dl 0deni
b5nru.. corn
Soil Compaction Report Client:
Test Method: ASTM D 6938
Project:
Terry & Heidi Ruonavaara
160 Springridge Drive
Glenwood Springs, CO 81601
20-7-105
Ruonavaara Residence
Hidden Valley Drive, Lot 59, Spring Ridge Res...
Glenwood Springs, CO 81601
Test Results
Test #
Retest
Of
Test
Date
Proctor ID
Method
Soil
Classification
Optimum
Moisture
(%)
Maximum
Dry Density
Oct)
In Place
Moisture
(%)
In Place
Dry Density
(pcf)
Probe
Depth
(In)
Percent
Compaction
MIn Comp.
(%)
Optimum
Moisture
Tolerance (%)
Remark
1 '
5/18/20
108-20
B 10898)
SM
114
118,0
10.4
118.9
8
101
95
-2 / 2
DP/MP
2
5/18/20
108-20
B (0698)
SM
11.4
118.0
13.7
110 3
8
93
95
-2 / 2
DF/MF
3
5/18/20
108-20
5 (0698)
SM
11.4
1186
8.8
107.3
8
91
55
-2/2
DF/MF
4
5/18/20
108-20
B (D698)
SM
11.4
118.0
10.8
131.1
6
111
95
-2 / 2
DP/MP
5
5/18/20
108-20
B moo '
SM
11.4
118.0
9.4
114.5
6
97
95
-2/2
DP/MP
6
5/18/20
108-20
B (D698)
SM
11.4
118.0
10.0
98.3
B
83
95
-2 / 2
DF/MP
Test Information
Test #
Teat Location
Elevation
Reference
Gauge
Make / Model / SN / Calibrated
Field Technician
1
Structural Fill: Fooling Backfin: Test 6, Center of west wing
1' below fooling grade
Troxler / 3430 / 25178 /
Clay Cavanaugh
2
Structural Fill: Fooling Backfill: Test 5, center of SW wing edge
1' below fooling grade
Troxler / 3430 / 25178 /
Clay Cavanaugh
3
Structural Fill: Fooling Backfill: Test 4. center of SE wing corner
1' below fooling grade
Trex119f / 3430 / 25176 /
Clay Cavanaugh
4
Structural Fill: Footing Bsd ill: Test 3,. 5 feet East of SW Corner
1' below fooling grade
Troxler / 3430 / 25178 /
Clay Cavanaugh
5
Structural Fill: Fooling Backfilf: Test 2, oenler of West Wing
1' below footing grade
Troxler / 3430 f 25176 /
Clay Cavanaugh
Et
Structural Fig: Fooling Backh(: Test 1. center of west Wing
1' below fooling grade
Troxler / 3430 1 251 78 /
Clay Cavanaugh
Remarks
Comments
DP/MP: Density Pass / Moisture Pass
DF/MF: Density Fail / Moisture Fail
DF/MP: Density Fail / Moisture Pass
Tests are "Direct Transmission" (Method A) unless probe depth is noted as
"Backscatter'' Gauge calibration data on file with the testing agency
This report presents opinions formed as a result of our observations of soil compaction. We have relied on the contractor to continue applying the recommended
compactive effort and moisture to the fill during times when our observer is not observing operations Tests are made of the soils only as believed necessary to
calibrate our observer's judgement Test data are not sole basis for opinions on whether the soils meets specifications These test results only apply to the
samples which were tested The testing report shall not only be reproduced, except in full, without the written approval of Kumar and Associates, Inc Nuclear
gauge density testing performed in accordance with ASTM D6938
Page 1 of
�t A
=tee_
{s,a,ar4seetarns.l.a. Soil Compaction Report Client:
Con ta[Mitl 4n0 r: =:.r : s rnlllneers
nafinkanmar"'1 s"` na Test Method: ASTM D 6938
kumaruca cam
Glenwood Springs
5020 County Road 154
Glenwood Springs, CO 81601
Phone: 970-945.7988
Protect:
Terry & Heidi Ruonavaara
160 Springridge Drive
Glenwood Springs, CO 81601
20-7-105
Ruonavaara Residence
Hidden Valley Drive, Lot 59, Spring Ridge Res.
Glenwood Springs, CO 81601
Test Results
Test #
Retest
Of
Test
Date
Proctor ID
Method
Soil
Classification
Optimum
Moisture
(%)
Maximum
Dry Density
(pcf)
In Place
Moisture
(%)
In Place
Dry Density
fpcf)
Probe
Depth
(In)
Percent
Compaction
Min Comp.
(%)
Optimum
Moisture
Tolerance (%)
Remark
7
- 5/20/20
108-20
B (0898)
SM
11.4
118.0
10.4
114.3
10
97
95
-2 / 2
DP/MP
8
5/20/20
108-20
B (0698)
SM
11.4
118.0
11.1
117.5
10
100
95
-2 / 2
DP/MP
9
5/20/20
108-20
B (7698)
SM
11.4
118.0
10.2
111.5
10
94
95
-2 / 2
DF/MP
Test Information
Test #
Test Location
Elevation
Reference
Gauge
Make / Model / SN / Calibrated
Field Technician
7
Structural Fill: Footing Backfill: Northwest Corner
5.0
Fooling Grade
Troxler / 3440/25081 /
Philip Orgill
8
Structural Fel: Footing Backfill: 35' south of northwest corner
5.0
Footing Grade
Troxler/ 3440 / 25081 /
PhIllp Orgill
9
Structural Fiii: Footling Bac d111: Southeast Comer
5.0
Footing Grade
Troxler/ 3440 / 25081 /
Philp OrF111
Remarks
Comments
DP/MP: Density Pass / Moisture Pass
DF/MP: Density Fail / Moisture Pass
Tests are "Direct Transmission" (Method A) wags probe 866111 ra 651ed at
"Backscatter" Gauge calibration data on file with the testing agency
This report presents opinions formed as a result of our observations of soil compaction. We have relied on the contractor to continue applying the recommended
compactive effort and moisture to the fill during times when our observer is not observing operations. Tests are made of the soils only as believed necessary to
calibrate our observer's judgement Test data are not sole basis for opinions on whether the soils meets specifications. These test results only apply to the
samples which were tested. The testing report shall not only be reproduced, except in full, without the written approval of Kumar and Associates, Inc. Nuclear
gauge density testing performed in accordance with ASTM D6938.
Page 1 of 1