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HEPWORTH-PAWLAK GEOTECHNICAL
August 31, 2015
Terry Davis
816 Whiteriver Avenue
Rifle, Colorado 81650
terry d34.td @gmaii.com
11crn•orth-PawIak Geotechnical, Inc.
5020 County Road 154
Glenwood Springc, Colorado 81601
Phone: 970.945-7988
Fax: 970-945-8.454
entail: hpgcoghpgeotech com
Job No. 115 112A
Subject: Observation of Excavation, Proposed Residence, Lot 28, Sun Meadows
Estates, South Meadow Circle, Garfield County, Colorado
Dear Mr. Davis
As requested, a representative of Hepworth-Pawlak Geotechnical, Inc. observed the
excavation at the subject site on August 25, 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 April 21,
2015, Job No. 115 112A.
The proposed residence will be one and two story wood frame construction above a
basement level and with an attached garage. Basement and garage floors will be slab -on -
grade. Our previous report recommended spread footings on the natural soils for
foundation support of the residence designed using an allowable soil bearing pressure of
2,000 psf, with some risk of movement.
At the time of our visit to the site, the foundation excavation had been cut in two levels
from about 3 to 12 feet below the adjacent ground surface. The soils exposed in the
bottom of the excavation consisted of sandy clay and silt. Results of swell -consolidation
testing performed on a sample taken from the site, shown on Figure 1, indicate the soils
are moderately compressible under conditions of loading and wetting. 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 2,000 psf. The risk of movement is
primarily if the bearing soils 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 and the subgrade compacted. Other recommendations presented
in our previous report which are applicable should also be observed.
Parker 303-841-7119 • Colorado Springs 719-633-5562 • Silverthorne 970-468-1989
Terry Davis
August 31, 2015
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,
HEPWORTH — PAWLAK GEOTECHNICAL, INC.
Louis E. Eller
Reviewed by:
eotte E3 01/4/
David A. Young, P.E.B ,� ; Lu
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Figure 1 — Swelf10611andation Test Results
LEE/ksw
attachment:
Job No. 115 112A
Compression %
0
1
2
3
4
5
6
7
8
9
10
Moisture Content = 5.6 percent
Dry Density _ 95 pcf
Sample of: Sandy Clay and Silt
From: Bottom of Excavation - West Side
Compression
upon
'wetting
0.1
1.0
APPLIED PRESSURE - ksf
10
100
115 112A
H
Hepworth—Pawlok Geotechnical
SWELL -CONSOLIDATION TEST RESULTS
Figure 1