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• Construction Inspection & Related Tests
ar son Testing, . Inc•
C Geotechnical Consulting
(k 4 / P.O. Oregon 14
April 22, 1 998 C, `�/ Tigard, Oregon 97281
Phone (503) 684 -3460
CTI #97
FAX (503) 684 -0954
aP h-C VA ` � ad s/
Matrix Development Corporation - to
6900 SW Haines Street - Suite #200M
Tigard, Oregon 97223 -2514 /
PARTIAL FINAL REPORT OF EARTHWORK OBSERVATION AND TESTI: G � /L V
APPLEWOOD PARK II
LOTS 15 THRU 29, 39, 45 THRU 48, 56 THRU 59, & 77 THRU 79
TIGARD, OREGON
Carlson Testing !nc. (CT!), has conducted on -cal! inspection services for the earthwork at the
above residential development located off SW Hall Blvd. and SW Settler ST. in Tigard, Oregon.
Although not all of the lots within the subdivision are ready for final inspection, the developer
has requested this letter summarizing our observations and testing during construction of the
above referenced lots. The attached plan indicates the lots being reviewed for the partial final
letter. This letter provides recommendations for foundation design and soil guidelines during
construction of the single - family homes on the lots in question.
SITE PREPARATION AND FILL PLACEMENT
Based on our field observations and density test results, no engineered fill has been placed on
any of the lots with the exception of Lot 77. From our conversation with Matrix Development,
we understand the subject lots were left near original grade. CTI visited the site on April 21,
1998, to review the existing soil conditions. From our observations, the majority of the lots
are covered with approximately 12 to 24 inches of uncompacted trench spoils, strippings
and /or water softened soils.
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HOUSE EXCAVATION GUIDELINES
The surface of the lots in question are covered with an roughly 12 to 24 inches of
uncompacted or water softened material. If the developer wishes to warrant the excavation
depth to suitable foundation �� bearing soil, we recommend that a minimum depth of 2 feet be
used. Some slightly deeper excavations may be required in isolated areas. If excavated
material is spread around the lot and is expected to support appurtenant structures such as
deck footings and sidewalks, it should be placed, compacted, and tested as engineered fill.
FOUNDATIONS
The proposed one- to three -story residential buildings will likely be founded on shallow spread
footings bearing on competent native soils or engineered fill. Spread footing design and
construction should generally conform to UBC Chapter 18 and /or Chapter 4 of the CABO One
and Two Family Dwelling Code, except where we specifically recommend otherwise.
For protection against frost heave we recommend that spread footings on nonexpansive soils
have a minimum final embedment depth of 12 inches for exterior grades on level ground;
however, it is likely that footing excavations will be significantly deeper to achieve adequate
bearing soil due to the soft surface soils. The recommended minimum widths for continuous •
wall footings are tabulated on the following page:
f ,
CTI #97-G1396
Applewood Park II
Page 2
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Minimum Width for
No. of Stories Continuous Footing
(floors supported) (in)
1 -story 12 •
2 -story 15
3 -story 18
The allowable bearing pressure can be taken as 1,500 lb /f for footings bearing on competent
native subsoils or engineered fill. The recommended maximum load is 15 kips for column
footings. For heavier column loads and masonry chimneys, a Soil Engineer should be
consulted. The coefficient of friction between on -site soil and poured -in -place concrete may
be taken as 0.35 for native soils and 0.40 for engineered fill. The maximum anticipated total
and differential footing movements are 1 inch and ' inch, respectively, over a span of 20
feet.
If requested, CTI can provide inspection services to verify that suitable foundation subgrade
is exposed prior to placement of concrete.
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CTI #97-G1396
Applewood Park II
Page 3
CLOSING AND LIMITATIONS
Our reports pertain to the materials tested /inspected only. This letter should be made available
to each builder in the development; however, information contained herein is not to be
reproduced, except in full, without prior authorization from this office. This letter should not
be construed to relieve or lessen the responsibility of the contractor or owner's site
representative for this site work, but is provided for the minimum required governmental
assurance. Our support was given on an as- needed basis as requested. If conditions are
encountered during foundation excavation which differ from this report, then the developer
(Matrix Development), the contractor (Schmidt Excavating) and CTI should be allowed to
review the condition before corrective actions are taken. Corrective work performed by the
builder without notifying the above parties will be interpreted as an acceptance of the
conditions encountered.
Respectfully submitted,
CARLSON TESTING, INC.
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OREGON
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Brian D. Leach, E.I. James D. Imbrie, P.E.
Engineering Associate Principal Engineer
cc: City of Tigard
Schimdt Excavating
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