Report Nev. 15. 2012 10:13AV No. 3394 P. 1
G eoP gcifig _
S Engineering, inc.
Real-World Geotochnlcal Solutions
•Investigation
• Design •
• Construction Support ?."
November 8, 2012 -
Project No. 03 -8449
• Stonebridge Homes Job No. 1486
• Attention: Andy Thomas_
Stonebridge Homes - ...
4230 SW Galewood St., Ste. 100
Lake Oswego, OR 97035 •
Fax 503 - 387 -7615 , . -
FOUNDATION SUBGRADE REVIEW
LOT 115 — ARLINGTON HEIGHTS NO. -
12758 SW WILLOW POINT LANE
CITY OF TIGARD, OREGON
GeoPacific Engineering Inc. visited the site yesterday to review the single family home foundation
subgrade on Lot 115. pi 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 9! inch,
respectively, over a span of 20 feet.
r
At the time of our site visit, the excavation was nearly complete and exposed compacted fill that - ,
probed stiff a depth of about 2 to 4 feetfhese_deeper"fill soils are considered adequate to
support the planned foundation loads. Footing to slope setbacks appeared adequate at
approximately 8 feet horizontal.
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 (503) 598 -8445
'• Portland, Oregon 97224 Fax (503) 941 -9281
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Nov. 15. 2012 10:13AY No. 3394 P. 2
GeoPacific tngmeermg, Inc.
Job No, 03 -8449
Lot 115 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,
GeoPaclfic Engineering, Inc.
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EXPIRES: 06/30120]
James D. Imbrie, G.E.
Geotechnica! Engineer