Report Jun. 29. 2007 9:56AM i 5 - 0 No. 1445 P. 1
GeoP tf
Engineering. hic.
June 28, 2007 Real -Wood Geotechnlcal Solutions
•Investigation
• Design
Project No. 07 -1137 • Construction Support
Chuck Arnett Custom Homes, Inc.
7288 SW 171 Drive
Aloha, OR 97007
Attn: Chuck Arnett
RE: GEOTECHNICAL REVIEW OF FOUNDATION EXCAVATION
HILLSIDE ESTATES LOT 7
TIGARD, OREGON
In May of 2007, representatives of GeoPacific Engineering, Inc. (GeoPacific) visited the project site
to observe removal of unsuitable fill materials from the western and southern portions of the
proposed house foundation. Poorly compacted fill with debris up to about 10 feet thick was removed
from the house foundation footprint area and beyond. Some of this unsuitable fill appears to extend
beneath the driveway turnaround area. The overexcavated areas were then backfilled with
imported reject rock and compacted. On -call density testing was performed to verify that adequate
compaction was achieved. Based on the results of our compaction tests, the granular fill was
compacted to at least 90% of the Modified Proctor at the tested locations.
On June 28, 2007, GeoPacific engineering geologist, Paul A. Crenna, visited the project site to
observe the subgrade conditions. The foundation footings are largely poured but the walls have not
yet been formed. Exposed native soil subgrade on the eastern portion of the excavation consists of
stiff to very-stiff clayey silt soil.
Based on the observed subgrade conditions and our density test results, we consider the foundation
excavation subgrade to be suitable for support of spread footings to a minimum allowable bearing
pressure of at least 1,500 psf. We recommend that additional compacted structural fill be placed in
the building interior once the foundation walls are completed in order to establish a minimum 1 H: 1 V
setback between footings and the base of cut slopes. GeoPacific should be contacted to verify
compaction of the recommended backfill. The rear footing -to slope setback is considered adequate
at approximately 8 feet horizontal.
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. This report
was prepared for Chuck Amett Custom Homes, Inc., only and should not be relied upon by third
parties without consulting GeoPacific.
•
7312 SW Durham Road Tel (503) 598 -8445
Portland, Oregon 97224 Fax (503) 598.8705
•