HomeMy WebLinkAboutObservation of Excavation 04.10.15~tech
HEPWORTH-PAWLAK GEOTECHNICAL
April 10, 2015
Dave and Kammy Young
3285 County Road 24 J
New Castle, Colorado 81647
11, p1111rth I'"' I 1k t ;,.,,,ldin1,.1I, r.,_
it•~t• 1 '1•11111\ R111 I I ~.J
t il,·111\•'"'I "11111;:,, l.11!.1ri,l 1 '-11"'1
I h1 ·n•·: •>it) 9 Ii i" .;:-,
11\ •1(1.l).j5:'1i.J
uu.111 hpi:u•1!lir~~·1t«li "'111
Job No. 108 621 A
Subject: Observation of Excavation, Proposed Residence, 3285 County Road 241,
Garfield County, Colorado
Dear Mr. and Mrs. Young:
As requested, a representative of Hepworth-Pawlak Geotechnical, Inc. observed the
excavation at the subject site on April 3, 2015 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
foundations at the site and presented our findings in a report dated August 12, 2009, Job
No. 108 621A. The current sit~ observation is in addition to our agreement for
professional services with you, dated November 10, 2008, for our previous study.
The proposed residence is located in the same area as previously proposed. Spread
footings placed on the natural soils and sized for an allowable bearing pressure of 2,500
psf were designed for the building support.
At the time of our visit to the site, the foundation excavation had been cut in 2 levels up to
11 feet below the adjacent ground surface. The downhill, southwestern side had minor
cut depth and the uphill, northeastern side had the deepest cut and stepped up about 4 feet
to the garage area with cut depth of 4 to 5 feet. The soils exposed in the bottom of the
excavation mainly consisted of silty sandy gravel and cobbles. A small area of clay soil
at the southwest side was dug down about 3 feet to remove the clay and replaced with
compacted onsite granular soils back to design footing grade. 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 compacted structural fill and spread
footings designed for the recommended allowable bearing pressure of 2,500 psf. Loose
disturbed soils in the footing areas should be removed or 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 excavation and the previous subsurface exploration at the
site. Variations in the subsurface conditions below the excavation could increase the risk
Parker 30)-84 I· 7 119 • Colorndo ~prings 719-6 B-5562 • Sd, l'rrhnrne 9i0-468-l 989
Dave and Kammy Young
April JO, 2015
Page 2
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 detennining 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.
1f you have any questions or need further assistance, please call our office.
Sincerely,
HEPWORTH -PAWLAK GEOTECHNICAL, INC.
Steven L. Pawlak, P.
SLP/ksw
Job No. 108 621A