HomeMy WebLinkAboutObservation of Excavation 02.04.16HEPWORTH-PAWLAK GEOTECHNICAL
February 4, 2016
RM Construction
Attn: Blake Piland
151 Clubhouse Drive
New Castle, Colorado 81647
(blake@buildwithrm.com)
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Job No. 115 533A
Subject: Observation of Excavation, Proposed Residence, Lot 33, Heron Crossing
at Ironbridge, 1651 River Bend Way, Garfield County, Colorado
Dear Mr. Piland:
As requested, a representative of Hepworth-Pawlak Geotechnical, Inc. observed the
excavation at the subject site on February 3, 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. We previously conducted a subsoil study
for design of foundations at the site and presented our findings in a report dated
November 30, 2015, Job No. 115 533A.
At the time of our visit to the site, the foundation excavation had been cut in one level
from 2 feet at the northern part to 3Vz feet at the southwest pan below the adjacent ground
surface. The soils exposed in the bottom of the excavation consisted of porous sandy silt
and clay. Results of swell-consolidation testing performed on a sample taken from the
site, shown on Figure l, indicate the soils are slightly compressible under light loading
and moderate to highly compressible when wetted and additionally loaded. No ice, snow
or water was observed in the excavation and the soils were slightly moist to moist. The
excavation base in footing areas had been compacted and was firm. The excavation base
was being protected from frost with insulated blankets.
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 with a settlement risk. Loose and
disturbed soils in the footing areas should be moistened and compacted. The bearing
soils should be protected from frost and concrete should not be placed on frozen soils.
Other recommendations presented in our previous report which are applicable, especially
those to keep the bearing soils dry, should also be observed.
Parker 303-841-7119 • Colorado Springs 719-633-5562 • Silvcrchornc 970-468-1989
RM Construction
February 4, 2016
Page2
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:
LEE/ljf
attachment Figure J -Swell-Consolidation Test Results
Job No . I IS S33A
Moisture Content = 7.5 percent
Dry Density = 91 pct
Sample of: Sandy Slit and Clay
From: Bottom of Excavation at Center of
0 Crawlsaace
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( Compression
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APPLIED PRESSURE· ksl
115 533A ~~
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SWELL-CONSOLIDATION TEST RESULTS Figure 1