HomeMy WebLinkAboutObservation of Excavation 09.27.2016HPEKUMAR
Geo echnlcal Engineering I Eng neering Geology
Materials Testing 1 Environmental
5020 County Road 154
Glenwood Springs, CO 81601
Phone: (970) 945-7988
Fax: (970) 945-8454
Email: hpkglenwood®kumarusa.com
September 27, 2016
Joe Hultquist
402 Munroe Street
Rifle, Colorado 81650
i oe @ you n g-sery ices.com
Subject:
Dear Joe:
Office Locations: Parker, Glenwood Springs, and Silverthome, Colorado
Project No. 16-7-393
Observation of Excavation, Proposed Shop Building, 540 Ridge Road, West of
New Castle, Garfield County, Colorado
As requested, a representative of H-P/Kumar observed the excavation at the subject site on
September 2, 2016 to evaluate the materials exposed for foundation support. The findings of our
observations and recommendations are presented in this report. The services are supplemental to
Hepworth-Pawlak Geotechnical's (now H-P/Kumar) agreement for professional services to you
dated July 17, 2014.
We previously observed backhoe pits at the site for design of the building foundation and
presented our findings in a report dated July 31, 2014, Job No. 114 282A. The proposed
construction is similar to that discussed in the report. Spread footings bearing on the bedrock
materials encountered at shallow depths designed for an allowable bearing pressure of 3,000 psf
were recommended for foundation support.
At the time of our site visit, the foundation excavation for six of the planned ten footing pads for
the building foundation had each been cut in one level from about 3 to 31/4 feet below the
adjacent ground surface. The materials exposed in the bottom of the excavations consisted of
weathered and medium hard sandstone/claystone bedrock. We understand similar bedrock
materials were exposed in the bottom of the other four footing pads when later dug. No free
water was encountered in the pad excavations and the bedrock materials were generally moist.
The conditions exposed in the excavations are consistent with those previously encountered on
the site and suitable for support of spread footings designed for the recommended allowable
bearing pressure of 3,000 psf. Loose and disturbed materials should be removed in the footing
areas to expose the undisturbed claystone/sandstone bedrock and the subgrade 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 excavations, information provided to us regarding the footing pad
excavations not observed by us, and the previous subsurface exploration at the site. Variations in
Joe Hultquist
September 27, 2016
Page 2
the subsurface conditions below the excavations 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 KUMA
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H -P .t KUMAR
Project No. 16-7-393