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Gee g
Engineering,lc
13110 SW Galbreath Drive
Sherwood, Oregon 97140
Tel (503) 625 -4455 • Fax (503) 625 -4405
March 23, 2011
Project No. 03 -8449
J.T, Roth Construction
12600 SW 72nd Ave., Ste. 200
Portland, OR 97223
Phone 503 -473 -3497
Fax 503 -624 -0239
FOUNDATION EXCAVATION REVIEW /1,57 --627 — O0 03 ,
LOT 91 — ARLINGTON HEIGHTS NO. 3
CITY OF TIGARD, OREGON /SW 6 SA) /92L/ NG70`✓ 7 -
GeoPacific Engineering Inc. visited the site today to review the single family home foundation layout on Lot 91.
We understand that the proposed building is a two -story daylight basement home. In our opinion, the observed
subgrade is generally adequate for support to an allowable bearing pressure of 1,500 psf. The expected
maximum anticipated total and differential footing movements (generally from soil expansion and /or
settlement) are 1 inch and 3 /4 inch, respectively, over a span of 20 feel
At the time of our site visit, soils exposed in foundation excavation consisted of predominantly moderately
compact reject rock that could be probed less than about 1 inch with medium pressure using a steel "T" bar
probe. These soils are considered adequate to support the planned foundation loads. Footing -to -slope
setbacks were at least 10 feet horizontal due to an excavating depth of about 6 feet at the rear of the home.
We also observed placement of a thin crushed rock layer to protect the subgrade.
We understand that the proposed residence will be a two- story single - family home. Due to high fines content
of the reject rock soils encountered throughout the site, all foundations should incorporate appropriate
drainage measures. Crawlspaces should be provided with a low -point drain and pass through pipes should be
installed through footings which would otherwise restrict water flow to the low -point drain.
Our work scope pertains to a geotechnical engineer's foundation excavation review only and the conditions
existing and exposed at the time of our site visit. Within the limitations of scope, schedule and budget,
GeoPacific attempted to execute these services in accordance with generally accepted professional principles
and practices in the fields of geotechnical engineering and engineering geology at the time the report was
prepared. No warranty, express or implied, is made. If you have any questions, please call.
Sincerely,
GeoPacific Engineering, Inc.
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James D. Imbrie, G.E.
Geotechnical Engineer "' ;<_:�'� .', � s � - ' (t
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