Report Mar. 1. 2012 5: 21 PM No. 2709 P. 1/2
GdI
Engineering, Inc.
l 14835 SW 72 Avenue
Portland, Oregon 97224
Tel (503) 598-8445 Tatum
March 1, 2012
MAR 8 2012
Project No. 03 - 8449
Stonebridge Homes Job No. 1445 CITY OFTIGARD
' BUILDING DIVISION
Attention: Dan Velasquez
Stonebridge Homes
4230 SW Galewood St., Ste. 100
Lake Oswego, OR 97035
Fax 503 -387 -7815 and 603 746 - 6214
FOUNDATION EXCAVATION REVIEW
LOT 74 — ARLINGTON HEIGHTS NO.3
15298 SW GREENRIDGE CITY OF TIGARD, OREGON PLACE 14/5r0 //'
GeoPacific Engineering Inc. visited the site last week to review the single family home foundation
layout on Lot 74. 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 % 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
3H:1V fill slope. We requested about 5 feet of deepening at the back of the home to get down to a
2H:1V setback from the face of the soil filled Lock -n -Load retaining wall below the home in order not
to surcharge it. Once the excavator deepened the back footing line he encountered suitable
engineered fill. After our second site visit, soils exposed in the bottom of the foundation excavation
consisted of predominantly very stiff silt fill with some rock. 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. 1.. 2012 5 : 21 PM GeoPacifi�'cr i nc.
Job No. 03-8449
Lot 74 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: 06/30/201
James D. Imbrie, G.E.
Geotechnical Engineer •