Report Mar. 2. 2011 10:47AM No. 1503 P. 1
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tnginecring,Inc.
yvi i �� � / D �/ Portland, SW Oregon 72 4
5 1 Po12 Durham
SW Oregon Road
Tel (503) 598 -8445 • Fax (503) 598.8705
March 2, 2011
Project No, 03 -8449
Attention: Blake Agate
Stonebridge Homes
4230 SW Galewood St., Ste. 100
Lake Oswego, OR 97035
Fax 503- 387 -7615
FOUNDATION EXCAVATION REVIEW
LOT 60 — ARLINGTON HEIGHTS NO. 1 o 2.6 T1 n'a. if ins- 6
CITY OF TIGARD, OREGON
GeoPacific Engineering Inc. visited the site today to review the single family home foundation layout
on Lot 60. We understand that the proposed building is a two -story home with a daylight basement.
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 feet.
At the time of our site visit, soils exposed in foundation excavation consisted of predominantly very
stiff loess and residual soil, on the front 1/4th of the excavation and weathered basalt rock on the
rear 3 /4ths. These soils are considered adequate to support the planned foundation loads. Footing -
to -slope setbacks are not an issue and foundation embedment depths appeared adequate,
Due to silty clay soils encountered throughout the site, all foundations should incorporate
appropriate drainage measures. Some minor trapped water was seeping from the rocky layers of fill.
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.
Care should be taken to avoid saturation or disturbance of footing subgrade soils during and after
excavation. If footing bearing soils become saturated or disturbed, any softened soil or slough
should be removed and replaced with crushed aggregate or additional concrete. In general, footing
excavations should be cleaned such that no more than about ' /z inch of loose soils is present prior to
pouring concrete.
A Mar. 2. 2011 10 : 47AM GeoPacifi2 1 y03+eeiP..n Inc.
Job No. 03 -8449
Lot 60 Arlington Heights No. 3
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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EXPIRES: 061301201L
James D. Imbrie, G.E.
Geotechnical Engineer