Report Apr. 24. 2013 4:28PM No. 3739 P. 3
Georgtitic
Engineering, Inc,
Real -World Geotechnical Solutions
• Investigation
Design
411■41:4W7P7 • Construction Support
April 24, 2013
Project No. 03
Stonebridge Homes Job No, 1449
Attention: Andy Thomas
Stonebridge Homes Vb ' 1 ,z& 13_ o6O 62_
4230 SW Galewood St., Ste. 100
Lake Oswego, OR 97035
Fax 503 -387 -7615
FOUNDATION SUBGRADE REVIEW
LOT 78 - ARLINGTON HEIGHTS NO. 3
15432 SW SUMMERVIEW DRIVE
CITY OF TIGARD, OREGON
GeoPacific Engineering Inc. visited the site last week to review the single family home foundation
layout on Lot 78. 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 a/4 inch,
respectively, over a span of 20 feet.
At the time of our first site visit, the excavation was nearly complete and exposed medium stiff to stiff
native soil. These materials are considered adequate to support the planned foundation loads.
Footing to slope setbacks are adequate and footing - to - wall setbacks are also adequate.
Due to relatively impervious soils encountered throughout the site, all foundations should incorporate
appropriate drainage measures in accordance with the International Residential Code. Adequate
crawlspace drainage is not something that geotechnical consultants can verify; the purpose of our
visit is for observations of foundation bearing conditions only.
Care should be taken to avoid saturation or disturbance of footing subgrade soils during and after
excavation. We observed some placement of crushed aggregate to protect the subgrade from wet
weather. 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 1 /2 inch of loose soils is present prior to
pouring concrete.
14835 SW 72 Avenue Tel (503) 598 -8445
Portland, Oregon 97224 Fax (503) 941 -9281
, ' Apr. 24. 2013 4:28PM No. 3739 P. 4
GeoPacific Engineering, Inc.
Job No. 03 -8449
Lot 78 Arlington Heights No. 3
Our work scope pertains to a geotechnical engineer's foundation excavation rev 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: 06/30120
James D. Imbrie, G.E.
Geotechnical Engineer