Report (55) 5tg 70
6eoP-efcific
Enpincenn(1.lnc
Real-World Geotechnical Solutions
Investigation•Design•Construction Support
February 5, 2016
I
Project No. 12-2704 Pt "1-26 s`r
Stonebridge Project No. 1870 O .7 9 t
Stonebridge Homes
4230 SW Galewood St., Ste. 100
Lake Oswego, OR 97035
Fax 503-387-7615
Email Andy(astonebridaehomesnw.com; JimDastonebridgehomesnw.com;
kristent dmhholdinasco.com
RE: FOUNDATION SUBGRADE REVIEW
SOUTH VIEW SUBDIVISION LOT 33
12030 TURNAGAIN DRIVE
TIGARD, OREGON r
References: GeoPacific Engineering, Inc., Geotechnical Explorations, Knauss Property
Subdivision, 12035 Southwest Beef Bend Road, Washington County, Oregon, report
dated August 10, 2012.
GeoPacific Engineering Inc. visited the site today to review the single family home foundation
subgrade on Lot 33. We understand that the proposed building is a two-story home, on downward
sloping lot. 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 % inch, respectively,
over a span of 20 feet.
At the time of our site visit, the excavation was as neariy complete. The excavation consisted of
predominantly stiff engineered fill soils that probed less than 1 to 6 inches with heavy pressure using
a steel "T" bar probe. Stiff native soils were reached at the rear footing line. These soils are
considered adequate to support the planned foundation loads. Footing-to-slope setbacks were
adequate and foundation embedment depths appeared adequate. Some structural backfilling will
likely be required.
Due to silty 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.
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.
14835 SW 72nd Avenue Tel (603)598-8445
Portland,Oregon 97224 Fax (503)941-9281
Project No. 12-2704
South View Lot 33
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:06130/2017
James D. Imbrie, P.E., G.E.
Geotechnical Engineer
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