HomeMy WebLinkAboutObservation of Excavation 10.07.2016H-PKUMAR
5020 County Road 154
Glenwood Springs, CO 81601
Phone: (970) 945-7988
Fax: (970) 945-8454
Email: hpkglenwood@kumarusa.com
October 7, 2016
Doolen Construction
Attn: Dave Doolen
3838 County Road 243
New Castle, Colorado 81647
dive(idoo1cnconst nletion.com
Subject:
Dear Dave:
Office Locations: Parker, Glenwood Springs, and Silverthome, Colorado
Project No. 16-7-129-1
Observation of Excavation, Proposed Sharp Residence, Parcel H, Cedar Springs
Ranch, 693 North Cedars Springs Ranch Road, Garfield County, Colorado
As requested, a representative of H-P/Kumar observed the excavation at the subject site on
October 5, 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. The
services are supplemental to Hepworth-Pawlak Geotechnical's (now H-P/Kumar) agreement for
professional services to Doolen Construction dated June 21, 2016.
We previously conducted a subsoil study for design of foundations at the site and presented our
findings in a report dated July 29, 2016, Job No. 16-7-129. The proposed construction is similar
to that discussed in the report. Spread footings designed for an allowable soil bearing pressure of
1.500 psf were recommended for foundation support with some risk of settlement.
At the time of our visit to the site, the foundation excavation which was essentially complete had
been cut in one level from about 2 to 5V2 feet below the adjacent ground surface. The soils
exposed in the bottom of the excavation consisted primarily of stiff, sandy silty clay. In the
south central portion of the excavation, medium dense basalt gravel and cobbles in a silty clay
matrix was exposed ay subgrade. Results of swell -consolidation testing performed on a sample
taken from the site, shown on Figure 1, indicate the clay soils are moderately compressible under
conditions of loading and wetting. No free water was encountered in the excavation and the soils
were generally moist apparently from recent rain.
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. The risk of settlement is due to the variable bearing conditions,
and especially if the bearing soils were to become wetted, and precautions should be taken to
prevent wetting. 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.
Doolen Construction
October 7, 2016
Page 2
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.
If you have any questions or need further assistance, please call our office.
Sincerely,
H -P : KUMAR
David A. Young, P.E.
DAY/ksw
attachment Figure
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idation Test Results
cc: Garfield County Building Dept. -. Jim Wilson(iwilson{ci?garfield-county.com)
H -P KUMAR
Project No. 16-7-129-1