Report 05/29/2003 17:36 FAX 503 224 7324 DUNN CARNEY 11001 /027
,Dun
Allen FACSIMILE TRANSMITTAL
Higgins
&Tongue
LLP
RECENED
JUN 0 6 2003
Date: May 29, 2003 CITY OF TIGARD Pages:
BUILDING DIVISION (including cover page)
To: Larry J. Blake, Jr.
Tele No.: (503) 228 -6200 Fax No.: (503) 228 -6222
Company: Blake & Buckler, L.L_P_
To: Al Shields
Tele No.: Fax No.: (503) 684 -7297
Company: City of Tigard
Client Mtr.: HEI20 -1
Re: City of Tigard v. Curtis Heintz & Renaissance
Comment: Jim Imbric, GeoPacific Engineering Report dated May 27, 2003.
ISI
Original Being REV ON
Transmitted ® Not sent I I Overnight mail ❑ First -Class mail D Other
FILE COPY
CITY OF TIGARD
Approved • (Iy);
Conditionally Approved ( );
For only PERMIT the NO. worg! gd �!� in: ,9474
See Lette I to: Follow ( );
Job Ad =se: A i/NX 3Ye ;t
By. 7. , 4 1- 1 Date:
851 SW Sixth Avenue, Suite 1500 ■ Portland, Oregon 97204 -1357 • 503 -224 -6440 • FAX 503 224 - 7324
::OD MA \GRP WISE\DUNN -C Alt POST t.0 L I ENTS:242U51.1
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05/29/2003 17:36 FAX 503 224 7324 DUNN CARNEY lI 002/027
MAY - 24 -2003 THU 02:44 PM RENAISSANCE HOMES FAX NO. 5036561601 P. 02 •
— • . ..� —• ..c. ..a....v r uu taQurcit.uric, rriu r°AC„t to
Gasp me
LIIQpILCflilq. Ire.
Re& -World Gsotnchntical Solutlona
investigation • Design • Construction Support
May 27, 2003 ,^w �.
Project No, 0 -6207 '` Ra � U
Steve Hunt
•
Renaissance Hamea, Inc.
1672 Willamette Falls Drive f�
West Linn, OR 97088
Fax (503) 656 -1601
SUBJECT: ROCK WALLS AND SLOPE EVALUATION
LOT 3 - ERICKSON HEIGHTS
TIGARD, OREGON
This letter presents oUr assessment, findings, and contusions for the rock walls on the above -
referenced lot. The main purpose of this work was to provide further evaluation ifoluding subsurface
explorations with a portable drill rig, global stability analysis, and more comprehensive evaluation of
rookery wall's adequacy with recommended remedial measures.
•
FIELD WORK
Our field geologist performed two borings in the rear yard of Lot 3 as shown on the attaohed Site
Plan and Cross Sections B and C-C'. The borings were drilled with a portable drill rig
suboernraaled from Subsurface Explorations to depths of 15.5 feet. Standard Penetration tests
were performed every 2.6 feet through the boring. For a detailed description of the soils, sea
attached boring logs.
ANALYSES
we performed global elope Mobility analyses for circular failure on zne tiered walls and slope on both
Cross Sections 8-15' and C-C'. We assumed shear parameters and unit weights based on our
experience in similar soil typee and based on the results of the SPT testa. The parameters assumed
are as follows:
Unit Saturated Angle of Equivalent Fluid Active Earth
Soil Type weight Unit Weight Cohesion internal Pressure
(pcf) (poT) (psi) Friction 2H: 1 V upelope
• rase
Native soils and 130 135 200 40 Wa
weathered rpck
Compacted FIII 125 180 100 - 33 50
Poorly Compacted i 25 130 100 26 60
Ff11
New Select 13o 135 0 38 40
Granular Fill
7612 ew Durham Road Tat (003) s9e -8Qr►3
Portland, Oregon 97224
Fox (sea) 555 -8705
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05)29/2003 17:36 FAX 503 224 7324 DUNN CARNEY 0003/027
MIRY -29 -2003 THU 02:44 PH RENAISSANCE HOPES FAX NO, 5036561601 P. 03
.
- .. u Boa . Umu . r • • - ---.-- --. -+-. .c.J u� iV t.N
PAOE 8
GEOPAcIFlc ENDINEERINa, Mo.
Project No. 43.6207
Lot 3 - Erickson Heights Rock Walla
The results of our stability analyses showed that the existing slope configuration has a ctor of-
Safety as low as 1.22.
CONCLUSIONS AND RECOMMENDATIONS
The upper 9 feet of fill in the borings was only moderately compact, and not likely to have been
engineered The existing MI behind the walls, with minor adverse inducement, has a high potential to
be subject to lateral movement unless remedial measures are undertaken. At a minimum, we
propose construction a new 7- to 8-foot tail engineered rookery retaining wall located 2 feet
horizontal in front of the existing lower Wall and after removal of 3 to 6 feet of fill behind the wall:
Backflll should be compacted to minimum of 90 percent of the modified Proctor maximum dry
density. Existing fill ramavel, placement of engineered fill, and construction of walls should be
observed by a geotechnical engineer or hie repreeentative. Rock walls should be Constructed in
general accordance with the attached detail, Figure 4.
Based on our analyses, such construction using compacted 4p-0 and/or reject rock should result in a
final Factor -of- Safety against sliding of at least 1,48, even Ignoring the effects of wall support. Our
conclusion assumes that that the swimming pool is adequately evaluated and repaired as
necessary. We currently do not know If the pool Is founded on compacted or engineered fill.
Evaluation of the pool Is currently beyond our work scope and would be difficult to adequately
evaluate using borings, but can most readily be performed by exploratory excavation during
reconstruction of the lower rockery well. It is our opinion, that evaluation of the swimming pool
eubgrade Is most appropriately performed during rookery wall reconstruction.
•
Page 2
___0.5/'29/2003 17:36 FAX 503 224 7324 DUNN CARNEY VI004 /027
• ,MAY-29, -2003 THU 02:44 PM RENAISSANCE HOMES FAX NO, 5036561601 P. 04
rat by
•
GrOPACIFIO ENGINEERING, INC.
Project No. 03 -8207
Lot 3 - Erickson Heights Rock Walls
LIMITATIONS
The homeowners should be aware that ®evereiy uncontrolled and concentrated runoff, leaking water
pipes, or other sources of potential localized elope saturation may reduce portions the wall Factor -
of- Safety and could oause movement of any type of retaining wall. We have included our Oat at
items to consider for maintenance of hillside homesftee to aid the homeowners In safeguarding
against such occurrences.
Within the limitations of scope, schedule and budget. GeoPaclfic attempted to execute our 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 No warranty
is expressed or implied_
Sincerely,
GEOPACI . ®INIl!RING, INC.
• 9
14743 ,
OREGON
9 23. Iv < e�G - o3
Janlesi` '",t•_'" ..E., C.EG.
Principal Geotechrrical Engineer
Attachments: figure 1 — Site Plan
Boring Logs Rr7 and 0-2
Figures 2 and 3 — Revised Cross Sections
Figure 4 - Rockery Wall Detail
Global Slope Stability Analyses
New Lower Rookery Wall Analysis
Maintenance of H Flomesites
•
Page 3
. 1Z /10/02 FRI 09:14 FAX 503 670 9147 CARLSON TESTING [d] 001
1 :k • •• • •• • • • Carlson Ge pc • . • • Main Office Salem Office Bend Office • • P.O. Box 23814 4060 Hudson Ave., NE P.O, Box 7918
A Division of Carlson Testing, Inc. • • • • • • • • Tigard, Oregon 97281 Salem, OR 97301 Bend. OH 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 2 • • • • • • • • ••
Albert Shield .• ••• .. ..
. . ....
City of TigardPuilkingcoila ji1o(ccment
13125 SW Ha2I Bdcletratd• • • • ••.
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 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 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.
Brian C. Ranney, G.I.T.
Geotechnical Staff
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ERICKSON HEIGHTS I43 •RV1'AININ6•ALLS AND 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.
Salem Office
`167
arlson Geolech 11Ca1 ... 8C� 3814
4050 Hudson Ave., PO s
••••••••• ••• •
A Division of Carlson Testing, ); .• '• • • • • • • • • p9 . Oregon 97281 Salem, OR 97301 Bend, OR 97708
Caoteohnioal Consulting . •: : : :.• • • • phone (503) 684.3460 Phone (503) 589.1252 Phone (541) 330 -9156
Construction inapeodon and Related isms • • • • . • • 'FAX (503) 670 -9147 FAX (503) 589 -1309 FAX (541) 330-8163
• • • ••• • S (T 2. - Vz9
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• December 18 • • • •
Mr. Steve Hunt
Renaissance l • • • • •
1672 SW Willainettc Fail•Dfive •
West Linn, Oregon 5f 06€ • •
Confirming Agreement for Construction Observation Services
Erickson Heights Rockery Walls Lots 1 -10
SW Kabie 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 Rockery Wall Observations. Our specific scope of services will include the following;
• Observe rockery wall subgrade soils.
6 Observe boulder placement
• Observe wall backlit! 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 e part -time,
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Erickson Heights Lots 1 -10
Tigard, Oregon - • • • • •
December 11, 21102 • i • • • • . • • • • •
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on -call basis during earthwork operations; however, we are prepared to perform full time
observation ayou, regrNst, • • • • •
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For budgetary:purpusest wa liev:e sssa,rned that each 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 cost 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.
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.
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 • • • • • • • •
Decsmber 11,2Q02 • ; • • • ; • •.: ; •
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authorization to proceed, we will notify the City of Tigard by letter to inform them that we have
been retainer.% bbseee ttib•rd -b4.. il2i?pg of the walls. Please feel free to call if you have any
questions or rcquirp attiortit irlfoton.
• ••• • • • • • ••
Sincerely,
CARLSON GEOTECHNICAL
' _
Brian C. Ranney, G.I.T.
Geotechnical Staff
•
J•: ne M. Niemer, RE.
6 • sal Geotechnical Engineer
A . . ments: Terms and General Conditions for Geotechnical Services
w k x * • ■ * * * x * Sr* * k * * v * * * * x * * * * * * k * * * * * * * * * * * * ***le * *
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 w. k.
Y . Date /2-A 7--
Firm ‘
rm t c_r`?/f - f - , 5 ,')S
Doc ID: P: \GEOTE - {\Projec±s [Engrec }12001 ProjectslErickson Heights Sub divisiontconf r ng agreement re -bui{d rock rralls.
Carlson Geotechnical Page 3 of 3
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> ,e son G e o. e ! + A. n 9 c a Main Office Salem Office Bend Office
�7 VV iJl.b • • • • • • P.O. Box 23814 4060 Hudson Ave., NE P.O. Box 7918
.. • . . . . . . . • . • .
A Division of Carlson Testing, Inc. ; ; : • : • • • • • • : Tigard, Oregon 97281 Salem, OR 97301 Bend, OR 97708
Geotechnical Consulting • • • • • . . . :Pflone (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
• • •.• • • •
.. • • • •• • • • •
CGT No. G0101867.E . • • •. : • : : . •
Permit No. Unavailakile =•• •:. '.' :.•
FIELD OBSERVATIOAI REPORT • .. ..
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DATES COVERED: �; �
PROJECT: Erickson Heights Subdivision - Lot 3
ADDRESS: 10832 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 3:45 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 3.
At the time of my observations, the residence was complete. The backyard of the residence had been
landscaped, and a pool had been constructed. Three rockery walls were located in the backyard of the
residence, one of which was constructed only on the west end of the lot. The other two walls ran the
length of the lot.
The upper rockery wall, which was constructed only on the west end of the lot, was approximately 2.5
feet high with a batter ranging from vertical to approximately 1 H:4V. The wall was backfilled with silt
soils, and the wall had been embedded into the subgrade. I did not observe a drain behind this wall.
The second rockery wall (down slope from the first, upper rockery wall) ranged from approximately 4 to
5 feet high, was poorly stacked, and contained negative batter in some locations. Generally, however,
the batter ranged from vertical to approximately 1H:8V. The boulders were not embedded into the
subgrade. This wall also appeared to have been backfilled with silt soils. I did not observe a drain
behind this wall. This wall is experiencing a surcharge from the wall above it.
The third wall ranged from 4 to 5 feet high, was generally poorly stacked, and lacked adequate batter.
The backfill appeared to be silt soils. I did not observe a drain behind this wall, and the boulders were
not embedded into the subgrade.
I left the site at 4:00 pm.
Brian C. anney, Jeanne M. Niemerl, 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 [0002
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• • RbCK SI2E SCH1`DULE "Eqn. --21'50D + 250) LBS- ROCKERY WALL DESIGN
•1•IjF. 3 MIN, WT .`LBS -Z' • TYPICAL SIZE (IN.) MAXIMUM WALL HEIGHT (H) _ 4 FEET
• • • • • • • • • • •
• • • . •
• • • • • • • • •,3. X 26 X 18 DRAWING NOT TO SCALE
• 4 ••• •1,500•
25X25X25
28 X 25 X 16
• .3. ••• . 1,Op0 . . •• 22X22X22
• ' ' LEVEL TO 2H:1V MAX. SLOPE
'i • ••• �dof •• , • 22X19X14
• 18X18X18
• ••• •
COMPACTED SILT
OR CLAY SOIL
J U G• i ((TM
, , ORE,- • N,�, - - - - -, 6.:.!- • ��" STABLE TEMPORARY CUT
`�i� 4 ±1 M IN. WT. °�°• (SLOPE A VARIES)
t' 250D +250 °D ' 1p v� q °Q G
`'. NE r . ta• ,- H s — riw ! l% - - ° ° C 4 " -0 CRUSHED AGGREGATE,
pla,izf . l 2•5A•e ) at c v;.4. COMPACTED IN 12 INCH LIFTS
0.35H 0„ a
y -OQ'
H
p.� ° °Ua^ 1112 "- OCRUSHEDAGGREGATE
° �• r � � 7 WITH NO MORE THAN 7% FINES
C _ � �°� PASSING THE No. 200 SIEVE.
- .�� bp° LIGHTLY TAMPED
0 ?003 6 IN. :�� :. .' 4IN. DIAM. MIN. PERFORATED PLASTIC PIPE
CITY OF TI SCHEDULE 40 or ADS HIGHWAY GRADE
BuICD'N $ O N KEYWAY •I
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G DI
0.4H MIN. FOR OSHA STABLE ROCK,
0 -5H MIN. FOR OSHA °TYPE A" SOILS. AND
CONSTRUCTION NOTES 0.6H MIN. FOR OSHA "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 subgrado 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 leas two 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. Backfll 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. -
P�. oN Carlson Testing, Inc.
• c . P.O. Box 23814 Erickson Heig1hts Subdivision CGT Job No. G0101867.E
.�• .. - Tigard, Ore 97281