HomeMy WebLinkAboutObservation of Excavation 10.23.2015~ech
HEPWORTH-PAWLAK GEOTECHNICAL
October 23, 2015
Key Elements Construction
Atln: Richard Kihnley
60 South gth Street, Suite 104
Carbondale, Colorado 81623
R ichard@kevelementsconstruction.com
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Job No. 115 514A
Subject: Observation of Excavation, Proposed Den Addition, 68 Bald Eagle Way,
Aspen Glen, Garfield County, Colorado
Dear Richard:
As requested, a representative of Hepworth-Pawlak Geotechnical, Inc. observed the
excavation at the subject site on October 22, 2015 lo evaluate the soils exposed for
foundation support. The findings of our observations and recommendations for the
foundation design are presented in this report.
The proposed den addition will be a single story structure supported on spread footings
with a slab-on-grade floor, located in an alcove between the existing slab-on grade garage
and the residence over crawlspace. An allowable maximum soil bearing pressure of
3,000 psf was assumed in the design.
At the time of our visit to the site, the foundation excavation had been cut in one level,
about three feet below the adjacent ground surface. The soils exposed in the bottom of
the excavation consisted of slightly silty sandy gravel with cobbles. We estimated that 1
to 1 V2 feet of existing foundation wall backfill was in place in the bottom of the footing
excavation. The base of the footing excavation had been compacted using a mechanical
tamper. One nuclear gauge moisture/density test performed in the base of the excavation
indicated a dry density of 133.2 pcf at 5.4 percent moisture. No free water was
encountered in the excavation and the soils were described as slightly moist to moist.
The soil conditions exposed in the excavation are consistent with those previously
encountered in the area and are suitable for support of spread footings designed for the
recommended allowable bearing pressure of 3,000 psf. The new footing should be
doweled into the existing foundation walls. If the soils in the new footing area are
disturbed they should be removed or re-compacted prior to concrete placement. The
bearing soils should be protected from frost and concrete should not be placed on frozen
soils.
Parker 303-841-7119 • ColoradoSprings 719-633-5562 •Silverthorne 970-468-1989
Key Elements Construction
October 23, 2015
Page 2
The recommendations submitted in this letter are based on our observation of the soils
exposed within the foundation excavation and our previous experience in the area.
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,
HEPWORTH -PAWLAK GEOTECHNICAL, INC.
Thomas J. Westhoff, CET
Reviewed by:
TJW/ksw
Job No . 115 514A