Report Mar. 8. 2012 3:38PM • No. 2746 P. 1/2
GeOP INC
Engineering, Inc.
14835 SW 72 " Avenue
Portland, Oregon 97224
Tel (503) 598 -8445 • Fax (503) 941 -9281
March 8, 2012
Project No. 03 -8449
Stonebridge Homes Job No. 1440
Attention: Andy Thomas
Stonebridge Homes
4230 SW Galewood St., Ste. 100
Lake Oswego, OR 97035
Fax 503 -387 -7615 and 503 - 746 -6214
FOUNDATION EXCAVATION REVIEW
LOT 69 — ARLINGTON HEIGHTS NO.3
- -t - 5340 SW SUMMERVIEW DRIVE
CITY OF TIGARD, OREGON J G plc/ 2. —DSO o
GeoPacific Engineering Inc. visited the site last week to review the single family home foundation
layout on Lot 69. We understand that the proposed building is a two -story home. 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 3 /4 inch, respectively, over a span of 20 feet.
At the time of our first site visit, the upper portion of the excavation was benched 2 to 4 feet into the
existing 25 percent side slope on the cut lot. We requested about 2 to 3 feet of deepening at the
east side of the home to get down to a 2H:1V setback from the face of the rockery retaining wall
below the home in order not to surcharge it. Once the excavator deepened the back footing line he
encountered suitably stiff native soils. These soils are considered adequate to support the planned
foundation loads.
Due to silty clay 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. 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.
Mar, 8. 2012 3: 39PNi GeoPacit �iyb P. inc.
Job No. 03 -8449
Lot 69 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.
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EXPIRES:. 06 /30 /20th
James D. lmbrie, G.E.
Geotechnical Engineer �r � '
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