Report 4
GeoPacitic
Engineering,Inc.
Real-World Geotechnical Solutions
•Investigation
•Design
•Construction Support
August 1, 2014
Project No. 03-8449 `!` Q, En
Stonebridge Homes Job No. 1485 2 7q- 1 )‘ "r'`
Attention: Andy Thomas and Jim Delmore tr,S7ycr/¢ —000 gq
Stonebridge Homes
4230 SW Galewood St., Ste. 100
Lake Oswego, OR 97035
• Fax 503-387-7615
Email Andy(stonebridgehomesnw.com; JimD(a.stonebridoehomesnw.com
FOUNDATION SUBGRADE REVIEW
LOT 114—ARLINGTON HEIGHTS NO. 3
12747 SW WILLOW POINT LANE
CITY OF TIGARD, OREGON
GeoPacific Engineering Inc. visited the site this week to review the single family home foundation
subgrade on Lot 114. The foundation excavation reached stiff native soils over most of the excavation
and some compact rocky fill near the rock wall. Some buried roots were present at the base of the fill
and necessitated added removals with concerns about the rock wall above. 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. Footing-
to-slope setbacks are adequate and footing-to-wall setbacks appear adequate provided the cast-in-
place concrete foundation wall is tall enough to support the rock wall to the west. The western
foundation wall should be backfilled with compacted crushed rock.
Due to relatively impervious 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'/2 inch of loose soils is present prior to
pouring concrete.
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.
14835 SW 72"d Avenue Tel(503)598-8445
Portland,Oregon 97224 Fax(503)941-9281
WIGeoPacific Engineering, Inc.
Job No.03-8449
Lot 114 Arlington Heights No.3 / [7"/�l q—00 9
Sincerely,
GeoPacific Engineering, Inc.
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EXPIRES:06130/20/5
::' James D. Imbrie, G.E.
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FOUNDATION CERTIFICATION
c. LOT 114 OF "ARLINGTON HEIGHTS NO. 3"
CITY OF TIGARD, WASHINGTON COUNTY, OR
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7-31-14
REGISTERED I, ROBERT RETTIG, A REGISTERED PROFESSIONAL LAND SURVEYOR IN THE STATE OF OREGON, HEREBY
PROFESSIONAL CERTIFY THAT I HAVE ACCURATELY STAKED THE FOUNDATION FOR LOT 114 OF 'ARLINGTON HEIGHTS
LAND SURVEYOR NO. 3" WITH HUBS AND TACKS.
// PREPARED FOR ARLINGTON HEIGHTS
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LO EG N STONE BRIDGE HOMES NW DRAWN BY:WCBICHECKED BY:RDR I DWG:2643CSTK lam: 2643
JANUARY 11, 2005 16869 SW 65TH AVE #505 AKS ENGINEERING & FORESTRY, LLC
ROBERT D. RETTIG LAKE OSWEGO, OR 97086 12965 SW HERMAN RD SUITE 100
6012415 TUALA11N, OR 97062 www.oks-eng.com
RENEWS: 12/31/14 PHONE: 503.563.6151 FAX: 503.563.6152 AMSC .