HomeMy WebLinkAboutObservation of Excavation 09.24.185020 County Road 1S4
Glenwood Springs, C0 81001
Phone: (970) 945-7989
Fax (970) 945-84s4
Email: hpkglenwood@kumarusa.com
Office Locations: Denver (HQ), Parker, Colorado Springs, Fort Collins, Glenwood Springs, Summit County, Colorado
September 24,2018
Daniel Gardner
134 County Road 303
Parachute, Colorado 81635
({anielc gardner @ exc.coml
Subject:
Project No. l8-7-381.4
observation of Excavation, Proposed Residence, Lot 30, First Eagles point, 2l I
Eagle Ridge Drive, Battlement Mesa, Garfield County, Colorado
Dear Mr. Gardner:
As requested, a representative of H-P/I(umar observed the excavation at the subject site on
September 5, 18 and 20,2Al8 to evaluate the soils exposed for foundation support. The findings
of our observations and recommendations for the foundation design are presenied in this report.
We previously conducted a subsoil study for design of foundations at the site and presentrd out
findings in a report dated June 29,2018, Project No. 18-7-381.
The proposed construction is similar to that discussed in our previous report. We recommended
spread footings bearing on natural gravel soils or compacted structural fill placed on gravel soils
to reestablish design footing grade for an allowable bearing pressure of 2,000 psf.
At the time of our September 5 site visit, the foundation excavation had been cut in one level
from? to 4 feet below the adjacent ground surface. The soils exposed in the bottom of the
excavation consisted of sandy clay and silt soils with scattered basalt gravel and cobbles. As per
our previous report, we recommended that the soil be removed down to the natural gravel
subsoils. When we returned on September 18, the fine-grained soils had been sub*excavated
about 2 ta 3 feet down to the basalt gravel and cobble soils. Imported structural fill (Class 6 road
base) had been placed in portions of the excavation. No free water was encountered in the
excavation and the soils were slightly moist.
On Septemb er 2},the structural fill under footing areas was tested for compaction by nuclear
gauge method. Imported structural fill consisting of importeds/q" road base reportedly had been
placed in l-foot lifts and compacted with vibratory compaction equipment. Test results showed
moisture content near optimum and compaction of LOOVo+ of maximum standard Proctor density.
The soil conditions exposed in the excavation are consistent with those previously encountered
on the site and the compacted structural fill over natural gravel soils is suitable for support of
spread footings designed for the recommended allowable bearing pressure of 2,000 psi. Other
recommendations presented in our previous report which are applicable should also be observed.
H.PVKUMAR
Geotechnlcal Enginecring I Enginccring Geology
Materials Test¡ng I Environmental
Daniel Gardner
September 24,2018
Page2
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 ofpractice should be consulted.
If you have any questions or need further assistance, please call our office.
Sincerely,
H.P\KUMAR
l/.*lffúfrÈ
Shane M. Mello, Staff Engineer
Reviewed by:
Steven L. Pawlak, P
SMI\,I/ljf
attachments: Figure 1 - Compaction Test Report
Figure 1A - Particle Size Distribution Report
Earthwork Compaction Testing Report: 9/Z0llB
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H-PVKUMAR
Project No. 18-7-381.4
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Test specification: ASTM D 698-12 Merhod C Standard
COMPACTION TEST REPORT
I
Water content, %
ZAV for
SP.G. =
2.63
7 o 10 1
o/o 1
No.200
1l
MATERIAL DESCRIPTION
Class 6 Aggregate Base Course
See Figure lA for classification results.
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ClassificationElev/
Depth uscs AASHTO
Nat.
Moist.sp.G.LL PI
o/o >
3l4in.
SP.SM A-1-a NV NP 0
TEST RESULTS
Maximum dry density: 130.9 pcf
Optimum moisture:8.8 %
Project No. l8-7-381.4 Client: Daniel Gardner
Project: Lot 30, First Eagles Point, 2l I Eagle Ridge Drive, Battlemenr Mesa, colorado
Number: 275-18o Sam
Kumar & Associates,nc.
Tested By KO Checked By:DEH
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Particle Size Distribution Report
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Sample Number: 275-18
% Flnes
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Material Description
Class 6 Aggregate Base Course
PL= NP
Atterberq Limits
LL= NV
CoefficientsDir= ¡on*
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uu=
Pl= NP
Dg6= 12.9615
Dan= 2.1641
Diı=Btg=uc=
3.9879
0.1500
USCS= SP-SM
Classification
AASHTO=A-1-a
Remarks
See Figure I for standard Proctor compaction results.
% Gravel % Sand%+3"Goarse Fine Coarse Med¡um Flne sitt
0 0 37 14 20 l8
Kumar & Associates, lnc.
Glenwood Springs, Colorado
Client: Daniel Gardner -''--
Project: Lot 30, First Eagles Point, 2l l Eagle Ridge Drive, Battlement Mesa,
Colorado
Project No: l8-7-381.A Fiqure 1A
Tested By:KO Checked By DEH
Test
No.
Location
Below Footing Structural Fill
Depth or
Elev.
Field Dry
Density
(pcÐ
Field
Moisture
Content
Yo
Field
Comp
(vo)
Min.
Comp.
Req.
(o/o\
Proctor
Lab No.
1 northeast corner footing
grade 134.4 5.8 100 98 275-18
2 southwest corner footing
qrade 133.9 5.4 100 98 275-18
15'south of northwest corner 134.8 r00 275-18
Lab No.Description
footing3 6.0 98
Method opt.
Moist.
Max. Dry
Dens.
275-18 ASTM D 698 3/t" aggÍegate base course 130.9 8.8
T \5020 County Road i54
Glenwood Springs, CO 91601
Phone: (970) 945-7989
Fax (970) 945-8454
Email: hokolenwood@kumarusa.com
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Office Locations; Parker, Glenwood Springs, and Silverthorne, Colorado
Earthwork Gompaction Testing Report
Client: DanielGardner
134 County Road 303
Parachute, Golorado 8l 635
Project No.: l8-7-381.4 Day:
Date:
Page:
Thursday
9/,20t18lofl
Project:Proposed Residence,Lot 30,First Eagles Point,2t 1 Eagle R¡dge Drive,Battlement Mesa,
Garfield c ou Golo rado
Weather: Partly cloudy, calm, dry Temperature:70o at 10:30 am
Earthwork Contractor:
Equipment Used:trackhoe, vibratory double drum roller
Description of Earthwork Below footing structural fill operations were comptete. All tests met minimumTested: proiect moisture/density specifications.
Sample(s) Obtained: yes, see Figures 1 and lA.
VerbalGommunication: AmyPerrin
Placement and Compaction Procedure: Not obserued by H-P/Kumar
Lift Thickness: two l' lifrs Max. Rock size: 3/t. 8;åTli,'å,.n, hydrant
double drum roller Number of passes:Com Used as uired
Nuclear Moisture/Den Test Results
Proctor Reference:
COMPACTIVE EFFORT AND MOISTURE
THE NUCLEAR DÊNSOMETER METHOD
TO FILL OURING THE TIMES WHEN OUR OBSERVER IS NOT OBSERVING OPERATIONS
OF TESTING WAS USED IN SUBSTANTIAL ACCOROANCE WTH ASTM D 693A,
Distribution:
Daniel Gardner ldaqielgEardner@exc.com)
Philio Oroill Shane Mello
lkac
Field Technician Reviewed By