Report Jul. 19. 2012 3:57PM No. 3100 P. 2
•
CooP dIC
Engineering, Inc.
RECEIVED
Real -world Geotechnical Solutions
• Investigation
JUL. 1 9 "" Design
• Construction Support
July 14, 2012 CITYOFTIGARD
BUILDING DIVISION
Project No. 03 -8449
Stonebridge Homes Job No. 1464
Attention: Andy Thomas
Stonebridge Homes
4230 SW Galewood St., Ste. 100
Lake Oswego, OR 97035
Fax 503 - 387 -7615
FOUNDATION SUBGRADE REVIEW O� Q
LOT 93 — ARLINGTON HEIGHTS NO.3 i�t S T- o�
15480 SW SUMMER VIEW DRIVE
CITY OF TIGARD, OREGON
GeoPacific Engineering Inc. visited the site today to review the single family home foundation layout
on Lot 93. 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 e/ inch, respectively,
over a span of 20 feet.
At the time of our first site visit, the excavation was nearly complete and exposed stiff to very stiff
compacted reject rock. These soils are considered adequate to support the planned foundation
loads. Footing to wall setbacks appeared adequate.
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 5W 72°d Avenue Tel (503) 598 -8445
Portland, Oregon 97224 Fax (503) 941 -9281
Jul. 19. 2012 3:57PM No. 3100 P. 3
GeoPacific hngmeertng, Inc.
Job No. 03 -8449
Lot 93 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.
14 PE/
f OREGON
/ ' ,
"'cam ac Q.
EXPIRES: 06180/20
James D. Imbrie, G.E.
- Geotechnical Engineer