Report Oct 30 2003 11:31HM GeoPacific Engineering, 1 503 - 598 -8705 p.1
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Real -World Geotechnical Solutions
Investigation • Design • Construction Support
October 30, 2003 RECEIVED
Project No. 02 -8072
Vista Northwest NOV 3 Nnf
P.O. Box 91459
Portland, OR 97291 CITY OF TIGARD
(Fax 503- 645 -2714) BUILDING DIVI.S
Subject: GEOTECHNICAL ENGINEER'S FOUNDATION EXCAVATION REVIEW
GREENBURG PINES LOTS 2, 6, 7, 8, AND 9
CITY OF TIGARD, OREGON
GeoPacific Engineer, Jim Imbrie, has visited the above - referenced lot on October 24'" and 30 The
purpose of our visit was primarily to review the foundation excavation subgrade. The native
subgrade soils consist of medium stiff silt that is prone to softening In wet weather. We
recommended overexcavation beneath footings and placement of 4 to 6 inches of compacted
crushed rock to prevent softening in wet weather. This thin layer of gravel need not be tested for
compaction, but should be visibly compact.
The current subgrade is considered adequate for spread foundation support. Based on our
observations, the foundation subgrade and excavation setbacks should be acceptable for support of
the proposed single - family home to a maximum allowable bearing pressure of 1,500 psf. No patio,
sidewalk or deck footing subgrades were observed. The minimum steel reinforcement should be
incorporated (two no. 4 bars in the footing and one in the stem wall.) if foundation cracking is desired
• to be Inhibited.
Our work scope for this phase of geotechnical review pertains to foundation bearing conditions
only and is 1lrrmited to the conditions existing and exposed at the time of our site visits. If you have
any further questions, please call.
Sincerely,
GEOPACIFIC ENGINEERING, INC. Gs "a
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14743 D
James D. Imbrie, P.E. v OREGON
Principal Engineer *i Z3. ,q9 E-1796.90-0.5"
£s O tt
7312 SW Durham Road Tel (503) 598 -8445
Portland, Oregon 97224 Fax (503) 598 -8705
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