Report 12/20/02 FRI 09:14 FAX 503 670 9147 CARLSON TESTING 1 001
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C arlson o ee g�a1 • Main Office Salem Office Bend Office
••• • • • • • • P.O. Box 23814 4060 Hudson Ave., NE P.O. Box 7918
A Division of Carlson Testipg : lrD. : : : • • • • • Tigard, Oregon 97281 Salem, OR 97301 Bend, OR 97708
Geotechnical Consulting Phone (503) 684-3460 Phone (503) 589 -1252 Phone (541) 330 -9155
Construction Inspection and Related Tests FAX (503) 670-9147 FAX (503) 589 -1309 FAX (541) 330 -9163
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Dec e beTg0, 200 •:. '.' :..
/054, Sc,J 14,1, €_ S�
Albert Shields
City or iga • Buliding lode nforcement
13125 ivy Mall :Bptjepard. :
Tigard, Oregen 97223 • •
Mr. Shields,
The purpose of this letter is to provide you with information regarding the rebuilding of
the rockery walls on lots 2 through 10 of the Erickson Heights Subdivision. We have
provided Renaissance Homes with a rockery wall design and a confirming agreement to
observe the reconstruction of the rockery walls. Provided our confirming agreement is
signed and returned to our office prior to the commencement of work, Carlson
Geotechnical will observe the reconstruction of the walls.
The general plan for reconstruction the walls is to remove each wall, excavate subgrade
soils to firm material, and rebuild the wall in accordance with our rockery wail design.
Once a particular wall is removed, we will observe the subgrade soils and make the
proper recommendation for over excavation of the subgrade. Once the subgrade is over
excavated, we will observe the keyway, foundation rock, and placement of the wall drain.
We will also observe compaction of the backfill aggregate, footing to slope (or adjacent
wall) set backs, and wall batter. Provided these items are performed in accordance with
our recommendations, we will provide a final letter of rockery wall observations to the
City of Tigard and Renaissance Homes.
If you have any further questions or comments, please contact our office.
r
Brian C. Ranney, G.I.T.
Geotechnical Staff
O arlsoi) V eo to h a i cal Main Office Salem Office Bend Office
• • • • • • • • POE Box 23814 40E4 Hudson Ave., NE P.O. Box 7918
:. • : : • • Tigard, Oregon 97281 Salem, OR 97301 Bend, OR 977CA
A Division cf Carlson:ratirty,'Ino.: •
Geoteohnioal Consulting* • • • • • • • • Phone (503) 694.3460 Phone (503) 585 252 Phone (541) 330 -9155
Construction Inspectitm &nd Reiat'ed To ' • " FAX (503) 670 -9147 FAX (503) 589 -1309 FAX (541) 330.9163
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Decerr►ber► 20U�• • :• :.•
Mr. Sty a l jitrlt • • • • • •
Renais*ncE He - n s
1672 S\DJ WiDarrietle rals:DrivE :
WVest LiAn, CSrrgo'n 97068' •
Confirming Agreement for Construction Observation Services
Erickson Heights Rockery Walls Lots 1 -10
SW Kable Street
Tigard, Oregon
INTRODUCTION
Carlson Ceotechnical is pleased to submit this confirming agreement to observe the re- building
of the upper rockery walls on lots 1 through 10 of the Erickson Heights Subdivision in Tigard,
Oregon. We have performed numerous observations of these rockery walls, the results of
which were presented in our Summary Report of Rockery Wall Observations dated October 25,
2002. In that report we recommended that the upper walls be re- built, and we provided a
general detail and written recommendations for rebuilding the rockery walls.
PURPOSE AND SCOPE
The purpose of our geotechnical construction observation services will be to confirm that the
rockery walls are re -built In accordance with the recommendations contained in our Summary
Report of Rookery Wall Observations. Our specific scope of services will include the following:
• Observe rockery wall subgrade soils.
• Observe boulder placement.
• Observe wall backfill compaction.
• Observe wall batter.
• Maintain periodic documentation of the construction activities and provide field
reports to Renaissance Homes and the City of Tigard.
• Submit a final letter of compliance regarding geotechnical- related activities.
FEE ESTIMATE
It is difficult to accurately estimate our total construction observation fees because our
involvement will depend on the rate at which construction proceeds, weather conditions, and the
number of site visits required. We anticipate that our services will be required on a part - time,
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Erickson Heights Lots 1 -10
Tigardi •f)rov •• •• ••• •••
Decenler 17, 1002 • . : • � : . •
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on -call basis during earthwork operations; however, we are prepared to perform full time
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observitlon et your request
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For budgetary putpoves, 'e have assumed that each part -time visit will requ;re a total of 3 hours
and will cost approximately $325 each. Each full time visit will require a total of 8 hours and will
cost approximately $650.00 each. This cost estimate includes vehicle mileage, and preparation
and review time for told reports. Our construction observation services will be conducted by a
member of our geotechnical staff and will be billed on a time- and - expense basis. All charges
will be provided in accordance with the attached Schedule of Charges and Terms and General
Conditions for Geotechnical Services. We are prepared to maintain a high level of
communication with the involved parties to keep close control of estimated and actual demand
for our construction observation services.
Satisfactory earthwork performance depends to a large degree on the quality of construction.
Sufficient observation of the contractor's activities is a key part of determining that the work is
completed in accordance with the construction drawings and specifications. Subsurface
conditions observed during construction should be compared with those encountered during
subsurface explorations, and recognition of changed conditions often requires experience. We
recommend that qualified personnel visit the site with sufficient frequency to detect whether
subsurface conditions change significantly from those observed to date and anticipated in this
report.
We recommend that rockery wall subgrades, placement of boulders, drain placement, wall batter,
and compaction of wall backfill be observed by the project geotechnical engineer, or their
representative.
SCHEDULE
Because observation is typically performed on an on -call basis, this agreement assumes that the
earthwork contractor is held contractually responsible for scheduling observation. Observations
should be scheduled a minimum of 24 hours in advance of when you would like the observation to
be performed.
CLOSURE
We appreciate the opportunity to submit this proposal and look forward to working with you on
this project. Please formally provide your authorization of the work described herein by signing
a copy of this proposal and returning it to our office. At your request, upon receiving written
Carlson Geotechnical Page 2 of 3
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Erickson Heights Lots 1 -10
Tigard, Oregon ... • • •
Decergt 19, 20Q2 •• • • • ' • • •
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authorization to proceed, we will notify the City of Tigard by letter to inform them that we have
been Pa'tairiarl te'obsewe: tt o - building of the walls. Please feel free to call if you have any
questiops ogreeViCe Vlaiii;draal, inform tion.
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Sincerely,
CARLSON GEOTECHNICAL
P ge...,----Ra------i
Brian C. Ranney, G.I.T.
Geotechnica Staff
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J ne M. Niemer, P.E.
A i cal Geotechnical Engineer
ments: Terms and General Conditions for Geotechnical Services
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The terms and conditions of this etter are hereby accepted, and authorization to proceed with
the above scope of work is give ' by the following signature. I have secured or verified right -of-
entry for this we k.
By .f� ' ; 1L J A Date ,� D
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lir
Firm `� () ).4-}b5 - 5, 1 1) s
Doc ID: P: \GEOTECH\?rojects (Engrec)12001 ProjectslErtckson Heights Suddlvision\confirming agreement re -build rock xa11s.DOC
Carlson Geotechnioai Page 3 of 3
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arlson G e®techrIca • • • • • • • • • • • • P.O. Box 23814 4060 Hudson Ave., NE P.O. Box 7918
A Divisior of Carlson'Testin• • . • • • • • • • • • Tigard, Oregon n 97281 Salem, OR 97301 Bend, OR 97708
Q �C•• .• • • • • • •
Geotechnical Consulting • • • • • Phone (503) 684 -3460 Phone (503) 589 -1252 Phone (541) 330 -9155 • Construction Inspection anc}Relaled Tests • • • •• FAX (503) 670 -9147 FAX (503) 589 -1309 FAX (541) 330 -9163
CGT No. G0101867.E
Permit No. Unav$ilablq •• ••• • • •
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FIELD OBSERVATI011 REPbRT" • "'
DATES COVERED4 •. • • • • October 17. .2002
• PR : :. trAk/grt I- teights Subdivision - Lot 2
ADDRESS: : . :. ••• r0$5/ •W;ISable Street, Tigard, Oregon
BY: Brian Ranney, G.I.T.
WEATHER: Cloudy, —60 °F
PURPOSE OF VISIT: Rockery Wall Observation
Carlson Geotechnical (CGT) Geotechnical Staff, Brian Ranney, arrived on site at 3:30 pm as requested by Steve
Hunt of Renaissance Homes (RH). I met with Steve on site. The purpose of my visit was to observe the rockery
walls located in the back of lot 2.
At the time of my observations, the residence was complete. The backyard of the residence had been
landscaped, and four rockery walls had been constructed on the sloping lot, thus making a benched backyard.
The upper rockery wall ranged between approximately 1 and 3 feet high, and ranged between vertical and an
approximately 1 H:4V batter. The boulders for the wall were not embedded into the subgrade. As seen through the
spaces between the boulders, the wall was backfilled with silt soils. Using moderate pressure on a '/2 inch
diameter foundation probe, I could penetrate the backfill up to 4 feet with relative ease. I did not observe a wall
drain behind the wall. There were several large spaces that could have been filled with smaller rocks. In general,
the boulders were poorly stacked.
The second wall (down slope from the first, upper wall) ranged from 2 to 5 feet high with a batter of approximately
1 H:4V. The backfill for this wall also consisted of silt, and I could probe the backfill 3 to 4 feet with relative ease.
The boulders in this wall were generally stacked in good contact with the underlying boulders. Some of the
boulders on the bottom of the wall had been embedded into the subgrade, but in general, the boulders were not
embedded. I did not observe a drain behind this wall. The distance between the upper wall and this wall ranged
from roughly 1.5 to 2.5 feet, and therefore this wall is experiencing a surcharge from the upper wall.
The third wall was approximately 3 feet high with a batter of nearly vertical to approximately 1 H:4V. The backfill
appeared to be 2 inch aggregate. The boulders were embedded into the subgrade and the wall stacking was
generally good. I did not observe a drain behind this wall. This wall is also experiencing a surcharge from the wall
above it.
The fourth wall was up to 4 feet high, and generally lacked adequate batter. The backfill appeared to be 2 inch
aggregate that may have been mixed with native soils. The stacking for this wall was also generally good.
I left the site at 3:45 pm.
Brian C. Ranney, G.I.T. ( Jeanne M. Niemer, P.E.
Geotechnical Staff Principal Geotechnical Engineer
Note: Our reports pertain to the locations observed at the time of our visit only. Information contained herein is
not to be reproduced, except in full, without prior authorization from this office.
DISTRIBUTION: Steve Hunt, Renaissance Homes. Fax: (503) 670 -8663
Steve Hunt. Renaissance Homes. Fax: (503) 656 -1601
01/02/03 THU 11:07 FAX 503 670 9147 CARLSON TESTING 41U1.1 L
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• ROCK S!E SCFTEDULE"(Egn. = 50D + 250) LBS- ROCKERY WALL. DESIGN
• 4 - • (F t ) MI WT, (LBS .I•. TOPICAL SIZE (IN,) • MAXIMUM WALL HEIGHT (H) _ 4 FEET
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• • • 4• � • • 1. • • • 4 X 26X 18 DRAWING NOT TO SCALE
25 X 25 X 25
� • � ••11 • 1,(j00•• •• 28X25X16
• • r 22X22X22
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LEVEL TO 2H:1V MAX. SLOPE
• 1 ••• : • • : 8X18X18 MP
▪ ••• • • • • • w•
• .COMPACTED SILT
OR CLAY SOIL
°• �,i (12 to 24 INCHES
, THICK)
�' • 1 .. oo o or
D °pa a
Off,_ • N - . , o • • �� STABLE TEMPORARY CUT
r `' ;: 4 ±1 MIN. WT. °° °0° °Q °, (SLOPE ANGLE VARIES)
T. '�
\ ••!." � •' 250D +250 �D �pv�bciG
— t
'0,,../k4.
° C : 4 " -0 CRUSHED AGGREGATE,
:PB 2•et%• I q ° lj , 7 COMPACTED IN 12 INCH LIFTS
- ° �� p v g,a
0.3511 ...r.;,,:,4,0-;,y p? _ �• ° °Ua^ 1 1/2 " -0 CRUSHED AGGREGATE
�C Zo WITH NO MORE THAN 7% FINES
L/ ' f� '° PASSING THE No. 200 SIEVE,
Vi ' n • LIGHTLY TAMPED
Jq 1 �� • _ — " A po
� 2 240 6 IN- el L =4 , iu' Tr _ 4 IN. DIANA. MIN. PERFORATED PLASTIC PIPE • CtT N� '� SCHEDULE 40 Or ADS HIGHWAY GRADE
eul CD I ��ti S/� - • KEYWAY ►I
0.4H MIN. FOR OSHA STABLE ROCK,
0.5H MIN. FOR K)SHA °TYPE A" SOILS, AND
CONSTRUCTION NOTES 0.611 MIN. FOR OSHA "TYPE B" SOILS
1. For walls supporting engineered fill, the fill should be overbuilt and the wail constructed against an excavation into already
compacted fill.
2. Keyway subgrado and embedment depth should be verified by CARLSON GEOTECHNICAL
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3. Rocks should have a cubical, tabular, or semi- rectangular shape that roughly matches the space created by the previous rock
course. Rocks should be laid flat with the long dimension oriented perpendicular to the wall and extending towards the excavation
face. Rocks should be staggered such that each rock bears on at least Iwo rocks below and vertical joints are discontinuous. Rock
placement and wall integrity should be checked (by builder) by lightly hammering on the top of each rock with excavator bucket.
4. Minimum rock sizes should be determined using the ROCK SIZE SCHEDULE above, where D is the distance from the base of the
rock to the top of the wall. Rocks should be no smaller than 500 lbs.
5. Voids greater than 6 inches wide where there is no contact between adjacent rocks should be chinked with a small rock.
6. Backfill behind the rocks should consist of an average 12 -inch -wide sheet of 4 "-0 well graded crushed aggregate with no more than
7% fines passing the U.S. Standard No. 200 sieve. Backfill should be placed in lightly compacted to an unyielding state in 12 Inch
lifts has each course of rocks is placed.
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"lit)... 04, , Carlson Testing, Inc.
P.O. Box 23814 Erickson Hei4hts Subdivision CGT Job No. 60101867.E
..�° - Tigard, Oregon 97281
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