Report Aug. 30. 2012 5.58PM No. 3202 P. 3
RECEIVED
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2012 T�N Engineering, Inc.
C ITYOFTIGAItD I
BUII,DINGDIVISION Real•Wortd Geotechnteal Solutions
• Investigation
� C 9 • Design
J • Construction Support
August 30, 2012
Project No. 03 -8449 LS )6 7 St- ��,� � `
Stonebridge Homes Job No. 1473 c
1/ j a ,) 6
Attention' Andy Thomas D 611
Stonebridge Homes
4230 SW Galewood St., Ste 100
Lake Oswego, OR 97035
Fax 503 -387 -7615
FOUNDATION SUBGRADE REVIEW
LOT 102 — ARLINGTON HEIGHTS NO.3
15367SW SUMMERVIEW DRIVE
CITY OF TIGARD, OREGON
GeoPacific Engineering Inc. visited the site yesterday to review the single family home foundation
subgrade on Lot 102. 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 $/4 inch,
respectively, over a span of 20 feet.
At the time of our site visit, the excavation was nearly complete and exposed stiff to very stiff native
silt soil, and weathered rock. These soils are considered adequate to support the planned
foundation loads. Footing to wall setbacks appeared adequate at more than 1 H:1 V from the base
of the wall.
Due to relatively impervious clayey silt 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 % inch of loose soils is present prior to
pouring concrete.
14835 SW 72 Avenue Tel (603) 698 -8445
Portland, Oregon 97224 Fax (503) 941 -9281
Aug. 3 0. 2012 5: 5 9 P M GeoPacifi cn n ee n n g , Inc.
Job No. 03 -8449
Lot 102 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.
g5� AGIN% 49
1
OREGON
D. 1t
EXPIRES: 06/30/20
James D. Imbrie, C.E.
Geotechnical Engineer