Report 1Z /Z0 /02 FRI 09:14 FAX 503 670 9147 CARLSON TESTING tJ 001
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..C Ge
®te c l V a l ' •' B p JCe Salem Office Bend Office
• • • • •P,O. O. B ox 23814 4060 Hudson Ave., NE P.O, Box 7918
A Division of Carlson Testing, Inc. • • • • • • Tigard, Otton 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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December 20, 2002 "' "' • ••• • •••
/ O s 0 S' .e Albert Shields • • • •.. • • . • . • City of Tigard Building codos !p forrrult • • • •
13125 SW Hall BoulevOrd.;. • •
Tigard, Oregon 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 wall 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 backliili 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.
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Brian C. Ranney, G.I.T.
Geotechnical Staff
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C arlson C eotechni a1 �n o � Salem office Bend Ica
• • p�aca �ga1 a 4040 Hudson Ave, NE P.O. Box 7918
A Division cf Carlson Testing, Inc. • : : . • ° : • ° : : ° :Tly rd, ortgo6 97281 SFJem, OR 97301 Bend, OR 97708
Geofeohnioal Consulting ;• • • • •. Phone (5o3) 684.3460 Phone (503) 589-1252 Phone (541) 330-9155 • Construction Inspection and Related Texts • • • • • • FRX (503 Q7b.9147 FAX (503) 589 -1300 FAX (541) 3309163
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December 11, 2002 • • ° • • •
Mr. Steve Hunt
Renaissance Homes •
1672 SW Willamette Fair Drive • • . • • . • •
West Linn, Oregon 97066 •••
Confirming Agreement for Construction Observation Services
Erickson Heights Rockery Walls Lots 1 -10
SW Kable Street
Tigard, Oregon
INTRODUCTION
Carlson Geotechnical 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 Rockery Wall Observations. Our specific scope of services will include the following:
• Observe rockery wall subgrade solis.
• 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.
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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
Tgard, Oregon ... • •
Decor oer 11, 2002 • • • • • • • • • • •
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on - call basis during earthwork operations; however, we are prepared to perform full time
observation at your request!. • • • • • • ••
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For budgetary purposes; wa• Cieve.assurte3 gigeach part -time visit will require 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 cast estimate includes vehicle mileage, and preparation
and review tIme for field 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.
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SCHEDULE
Because observation is typicaily 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.
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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 Geotechr+.ical Page 2 of 3
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Erickson Heights Lots 1 -10
Tigard, Oregon
December 11, 2002 • • • • • • • • • • • • • •
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authorization to proceed, we will notify the City of Tigard by letter to inform them that we have
been retained to obsend ttiD r%ttiiiliilgg rf.tl veils. Please feel free to call if you have any
questions or require ad3itionpl irjfvrrrj
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Sincerely,
CARLSON GEOTECHNICAL
1- "P-pi.4,----R
Brian C. Ranney, G.I.T. t
Geotechnical Staff
Jr; n e M. Niemer, P.E.
..al Geotechnical Engineer .
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A.. ments: Terms and General Conditions for Geotechnical Services
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The terms and conditions of this etter are hereby accepted, and autorization to proceed with
the above scope of work is give ' by the following signature. I have secured or verified right -of-
entry for this wil k.
BY : dl . i : AL A Date
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Firm J`? 5 5 1)C
Doc ID: P: \GEOTECH\Projects (Engrec)0001 ProjectslErickson Heights SubdlvIsionlconrrrming agreement re -build rock walts.DOC .
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Carlson Geotechnical Page 3 of 3
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C arlson Geotechnical Main Office Salem Office Bend Office
• • • • • • • • ;.. � o41, 23814 4060 Hudson Ave., NE P.O. Box 7918
A Division of Carlson Testing, Inc. • •• ; :.• : • • : • g 'd ,•Ore on 97281 Salem, OR 97301 Bend, OR 97708
Geotechnical Consulting ••• • • • f (503;6 :4 -3460 Phone (503) 589 -1252 Phone (541) 330 -9155
Construction Inspection and Related Tests • • • • • • T (503)'Z7i5-9147 FAX (503) 589 -1309 FAX (541) 330 -9163
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CGT No. 60101867.E •• • • • � • • • •
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Permit No. Unavailable •
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FIELD OBSERVATION REPORT
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• DATES COVERED: Octoter 1� 4412••• • • • •
PROJECT: EricKsor4:1,eiNirs Lot 4
ADDRESS: 10810 SW Kable 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 4:00 pm as requested by Steve
Hunt of Renaissance Homes (RH). The purpose of my visit was to observe the rockery walls located in the back
of lot 4.
At the time of my observations, the residence was complete. The backyard of the residence had been
landscaped, and a small structure (playhouse) had been constructed on the top of the second of four rockery
walls that had been constructed in the backyard of the residence. A concrete patio was located between the
residence and the first rockery wall.
The upper rockery wall (first wall), ranged between 4 and 5.5 feet high, and had a batter that ranged from vertical
to approximately 1H:10V, and was poorly stacked. The wall backfill consisted of silt. Using a '/2 inch diameter
foundation rod, I could probe the backfill the entire length of my probe (4 feet) with relative ease. The boulders
appeared to have been embedded into the subgrade. I did not observe a drain behind this wall.
The second wall (down slope from the first wall) ranged from 3.5 to 5 feet high, and had a batter that ranged from
vertical to approximately 1 H:4V, and was poorly stacked. The wall was backfilled with silt soils that I could probe 4
feet with relative ease. A playhouse with concrete foundations had been constructed on top of this wall. One side
of the foundation of this playhouse had been poured directly on top of the boulders for the rockery wall. The
playhouse is adding a surcharge onto this wall.
The third rockery wall was four feet high, had a batter of approximately 1H:4V, and was backfilled with what
appeared to be 2 inch minus crushed aggregate. Probing of the aggregate indicated that is was loose to medium
dense. The boulders for this wall were generally well stacked, however some areas of the wall were poorly
stacked. The bottom course of boulders for the wall were embedded into the subgrade. Two deck footings
associated with the playhouse had been poured on top of this wall. These footings are surcharging the wall.
The fourth rockery wall was constructed much like the third wall. The wall ranged from approximately 4 to 4.5 feet
high, had a batter of approximately 1H:4V, and was backfilled with 2 inch minus aggregate. The boulders for this
wall were also generally well stacked, however some areas of the wall were poorly stacked The bottom course of
boulders were embedded into the subgrade.
I left the site at 4:00 pm.
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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 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 41 UU2
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• I1OL`K SIZE SSFiEDULE = 50D + 250) LBS. ROCKERY WALL DESIGN
•*: (F.1) Mi.M- 1 • le•I;ICAL SIZE (IN.) i MAXIMUM WALL HEIGHT (H) _ 4 FEET
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• • • 4• � • • • • 1, 8 00 • • • • DRAWING NOT TO SCALE
25X25X25
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••• • 1 .4 00 •• •• 28X25
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• . • . 22X22X22
• • 22 X 19 X 14 LEVEL TO 2H:1V MAX. SLOPE
1 : : . ' • • ' 18X18X18
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COMPACTED SILT
OR CLAY SOIL
• ,,-4,:,,.„"
(n °` THICK)
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� : ' (,' �, _ _— 4 ad o '
f J Pf. .�a /�
„ V � 1 �� c eQ U
0 _ °per ; ".
' STABLE TEMPORARY CUT
i`'•4� 7,� ' •4±1 MW. wT. °,O ° A ° V'. (SLOPE ANGLE VARIES)
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P - _ ' ' 250D +250 - bepv� qU
S. O 4 " -0 CRUSHED AGGREGATE,
mac t2• st•o 9 ....‹),,;...g, .. COMPACTED IN 12 INCH LIFTS
' 50 0 °O
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0.35H �f 'bow c
Fl4 "I - jn
Q.
_ �• ° ° ua� 1 112 " -0 CRUSHED AGGREGATE
•��� �0 WITH NO MORE THAN 7° /a FINES
s►• _ . PASSING THE No. 200 SIEVE,
.126a&li r O ,, LIGHTLY TAMPED
/ JAN 0 2 20 6 IN. 9 ; 4i ; ' ' 4IN. DIAM, MIN. PERFORATED PLASTIC PIPE
CITY OF SCHEDULE 40 or ADS HIGHWAY GRADE
BUILDI D �V • 8 D . 1 P i
KEYWAY
iv 0.4H MIN_ FOR OSHA STABLE ROCK,
0.5H MIN- FOR OOSHA "TYPE A" SOILS. AND
CONSTRUCTION NOTES 0.6H MIN. FOR OOSHA "TYPE B" SOILS
1. For walls supporting engineered fill, the fill should be overbuilt and the wall constructed against an excavation into already
compacted fill.
2. Keyway subgrade and embedment depth should be verified by CARLSON GEOTECHNICAL
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 perpendldular to the wall and extending towards the excavation
face. Rocks should be staggered such that each rock bears on at leash two rocks below and vertical joints are discontinuous_ Rock
placement and wall integrity should be checked (by builder) by lightly hpmmering on the top of each rock with excavator bucket.
4. Minimum rock sizes should be determined using the ROCK SIZE SCHEDULE above, where 0 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.
Pte. o, . Carlson Testing, Inc.
„ r P.O. Box. 23814 Erickson Heig Subdivision CGT Job No. 60101867.E
.... . Tigard, Oregon 97281
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ERICKSON HEIGHTS II, RETAIN4NG VAbLS.4ND•FILL
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Lot No. Permit No. Street Address
2 SIT2002 -00028 10856 SW Kable St.
3 SIT2002 -00029 10832 SW Kable St.
4 SIT2002 -00030 10810 SW Kable St.
5 SIT2002 -00027 10788 SW Kable St.
6 SIT2002 -00031 10722 SW Kable St.
7 SIT2002 -000XX 10690 SW Kable St.
8 SIT2002 -00032 10652 SW Kable St.
9 SIT2002 -00033 10630 SW Kable St.
10 SIT2002 -00034 10600 SW Kable St.