HomeMy WebLinkAboutObservation of ExcavationF{ËPWORTH . PAWLAK GËOTHCHNICAL
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Tom Reed
635 East 4th Street Road
Eaton, Co. 80615
mrman635
Job No. 116 177
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Subject:Observation of Excavation, Proposed Residence, I,ot2, Overview
Subdivision, 8382 County Road 115, Garfield County, Colorado
Dear Mr. Reed:
As requested, a representative of Hepworth-Pawlak Geotechnical, Inc. observed the
excavation at the subject site on May 9, 2016 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
fotrndations at the site and presented our findings in a report dated July 3I,2007 , Job No.
107 0440.
The proposed residence will be one story wood frame construction above a walkout
basement. Basement floor will be slab-on-grade.
At the time of our visit to the site, the foundation excavation had been cut in one level
from 4 y2 to 7 feet below the adjacent ground surface with a small stepped down arca at
the southwest corner. The soils exposed in the bottom of the excavation consisted of
clayey sandy gravel with cobbles and boulders. The results of a gradation analysis
performed on a sample of clayey sandy gravel with cobbles (minus 5 inch fraction)
obtained from the site are presented on Figure 1. No free water was encountered in the
excavation and the soils were slightly moist to moist.
The soil conditions exposed in the excavation are consistent with those previously
encountered on the site and suitable for support of spread footings designed for the
recommended allowable bearing pressure of 1,500 psf. Loose and disturbed soils should
be removed in the footing areas to expose the undisturbed natural soils. Other
recommendations presented in our previous report which are applicable should also be
observed.
The reeommendations submitted in this letter are based on our observation of the soils
exposed within the foundation excavation and the previous (limited) subsurface
exploration at the site. Variations in the subsurface conditions below the excavation
could increase the risk of foundation movement. Vy'e should be advised of any variations
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Farker 303-841"711t) o Cirlqrr:rdo Springs 719'-6ij-5562 . Silve¡'thorrs 97ii-4.{>8-lÇ8{)
Tulr Reed
i|l4.ay 12,2016
Page2
encountered in the excavation conditions f'or 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,
HEPWORTH _ PAV/LAK GEOTECHNICAL, INC.
E. Eller
Reviewed by:
Daniel E. Hardin, P.E
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attachments Figure I -Results
cc Glenwood Structural & Civil - Adolfo Gorra (gsc@sopris.net)
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U.S. STANDARD SERIES CLEAR SQUARE OPENINGS
TIME READINGS #16 #8 +4 318"gl4^ I 112', 3" 5"6" I'100
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100 .300 .600 1.18 2.36 4.75 9.5 19.0 37 .5 76.2 152 203
t¿t001 .002 .005.009 .019 037 074 150 t¿,J
DIAI\/ETER OF PARTICLES IN MILLIMFTERS
COBBLES
CLÂYfO SILT
GRAVEL 68 VO SAND 15 % SILTANDCLAY 17 %
PLASTICITY INDEX %
FROM:Boüom of Excavation, East Side
LIOUID LIMIT %
SAMPLE OF: Clayey Sandy Gravelwith Cobbles
Figure 1GRADATION TEST RESULTS
116 1774