HomeMy WebLinkAbout03319 - Technical Information Report - Geotechnical,.,
���: i. .s -..�T� :�+ _�.t d `�ti� .:�Y�3�A(':'f._ "v»,:�:�. r,:,iFw �:».�F , s t a.:� t-.. _ . . ...:.'� !r� r^ _':�'aLR i:sY,:`i�n+:
GEOTECHNICAL ENGINEERING STUDY
STONE RIDGE III RESIDENTIAL DEVELOPMENT
148T" AVENUE SOUTHEAST N�AR
STATE ROUTE 900
DEVELOPMEM P�NNING
RENTON, WASHINGTON CITY OF RENTON
-11 Q69-3 �- � �1 OCT 2 8 2004
i� � t„ .1�.,,,. {, �
� �.� , _�~_ �ECENED
October 14, 2004
PREPARED FOR
KBS III, LLC
�%`7
�
S . Riegel
Staff Geologis
,, �.-
� �p� A• c
o�,
� �
�a �' cn
� 'o Is��`''
� �P ia
�� �, I
,
�]AL l��
_�
FXPIR"S`l /Zp'�/ '
� CJ
Raymond A. Coglas, P.E.
Manager of Geotechnical Services
Earth Consultants, Inc.
1805 - 136th Place Northeast, Suite 201
Bellevue, Washington 98005
(4251 643-3780
Toll Free 1-888-739-6670
_„ , . .. -�,,•-..s.,' , :h'�- . , . � _ . -. . . . .... ��' _ . . • - • . . . ." - . , , ....;r..-.,t- .. . .< _.;T.�.-�rs�+EF�t,•
s'
33�� o�.o�
IMPORTANT INFORMATION
ABOi1T YOUR
GEOTECHN�CAL ENGINEERING REPORT
More construction problems are caused by site subsur- technical engineers who then render an opinion about
face conditions than any other factor. As troublesome as overall subsurface conditions, their likely reaction to
subsurface problems can be,their frequency and extent proposed construction activity, and appropriate founda-
have been lessened considerably in recent years,due in tion design. Even under optimal circumstances actual
large measure to programs and publications of ASFE/ conditions may differ from those inferred to exist,
The Association of Engi�eering Firms Practicing in because no geotechnical engineer, no matter how
the Geosciences. qualified,and no subsurface exploration program, no
The foilowing suggestions and observations are offered matter how comprehensive,can reveal what is hidden by
to help you reduce the geotechnical-related delays, earth, rock and time. The actual interface between mate-
cost-overruns and other costly headaches that can rials may be far more gradual or abrupt than a report
occur during a construction project. indicates. Actual conditions in areas not sampled may
differ from predictions. Nothing can be done to nrevent the
unanticipated, but stens can be tahen to help minimize their
A GEOTECHNICAL ENGINEERING �mpact. For this reason, most experienced owners retain their
REPORT IS BASED ON A UNIQUE SET 9Qotechnical consultants through the construction stage,to iden-
tify variances,conduct additional tests which may be
OF PROJECT SPECIFIC FACTORS needed,and to recommend solutions to problems
A geotechnical engineering report is based on a subsur-
encountered on site.
face exploration plan designed to incorporate a unique SUBSURFACE CONDITIONS
set of project-specific factors.These typically include:
the general nature of the structure involved, its size and CAN CHANGE
configuration; the location of the structure on the site
and its orientation; physical concomitants such as Subsurface conditions may be modified by constantly-
access roads, parking lots, and underground utilities, changing natural forces. Because a geotechnical engi-
and the level of additional risk which the client assumed neering report is based on conditions which existed at
by virtue of limitations imposed upon the exploratory the time of subsurface exploration,construction decisions
program. To help avoid costly problems,consult the should nnt be based on a geotechnical engineering report whose
geotechnical engineer to determine how any factors adequacy may have heen affected by time. Speak with the geo-
which change subsequent to the date of the report may technical consultant to learn if additional tests are
affect its recommendations. advisable before construction starts.
Unless your consulting geotechnical engineer indicates Construction operations at or adjacent to the site and
otherNisz, your geotedTnical engineering report should not natural events such as floods, earthquakes or ground-
be used: water fiuctuations may also affect subsurface conditions I
•When the nature of the proposed structure is and, thus,the continuing adequacy of a geotechnical i
changed, for example, if an office building wili be report. The geotechnical engineer should be kept i�
erected instead of a parking garage,or if a refriger- apprised of any such events,and should be consulted to
ated warehouse wili be built instead of an unre- determine if additional tests are necessary.
frigerated one;
•when the size or configuration of the proposed GEOTECHNICAL SERVICES ARE
structure is altered; PERFORMED FOR SPECIFIC PURPOSES
•when the location or orientation of the proposed AND PERSONS
structure is modified;
•when there is a change of ownership,or Geotechnical engineers' reports are prepared to meet
•for application to an adjaeent site. the specific needs of specific individuals.A report pre-
Geotechnical engineers cannot accept responsibilitu for problems pared for a consui�ing civil engineer may not be ade-
wHich may develon i�they are not consulted after/actors consid- quate for a construction contractor,or even some other
ered in their report's deveEopment have chan_qed. consulting civil engineer. Unless indicated otherwise,
this report was prepared expressly for the client involved
and expressly for purposes indicated by the client. Use
MOST GEOTECHNICAL "F[NDINGS'� by any other persons for any purpose,or by the client
ARE PROFESSIONAL ESTIMATES for a different purpose, may result in problems. No indi-
vidual other than the client should apply this report for its
Site exploration identifies actual subsurface conditions intended purpose without�irst conferring with the geotechnical
only at those points where samples are taken,when engineer. No person should apply this report jor any purpose
they are taken. Data derived through sampling and sub- other than tHat originally contemplated u�ithout�irst conferring
sequent laboratory testing are extrapolated by geo- u�ith the geotechnicaf engineer.
A GEOTECHNICAL ENGINEERING der the rnistaken impression that simply disdaiming re-
REPORT IS SUBJECT TO sponsibility for the accuracy of subsurface information
always insulates them from attendant liability. Providing
MISINTERPIZETATION the best available information to contractors helps pre-
Costly problems can occur when other design profes- vent costly construction problems and the adversarial
sionals develop their pians based on misinterpretations attitudes which aggravate them to disproportionate
of a geotechnical engineering report.'Ib help avoid scale.
these probtems, the geotechnical engineer should be READ RESPONSIBILITY
retained to work with other appropriate design profes-
sionals to exp(ain relevant geotechnical findings and to CLAUSES CLOSELY
review the adequacy of their plans and specifications
relative to geotechnical issues. Because geotechnical engineering is based extensively
on judgment and opinion, it is far less exact than other
design disciplines. This situation has resulted in wholly
unwarranted claims being iodged against geotechnical
BORING LOGS SHOULD NOT BE consultants.To help prevent this problem,geotechnical
engineers have developed model clauses for use in writ-
SEPARATED FROM THE ten transmittals.These are not exculpatory dauses
ENGINEERING REPORT designed to foist geotechnical engineers liabilities onto
someone else. Rather, they are definitive clauses which
Final boring logs are developed by geotechnical engi- identify where geotechnical engineers responsibilities
neers based upon their interpretation of field logs begin and end.Their use helps all parties involved rec-
(assembled by site personnel)and laboratory evafuation ognize their individual responsibilities and take appro-
of fieid samples. Only final boring logs customarily are priate action. Some of these definitive c]auses are likely
induded in geotechnical engineering reports.These logs to appear in your geotechnical engineering report,and
should riot under any circumstances be redrawn for inclusion in you are encouraged to read them closely.Your geo-
architectural or other design drawings, because drafters technical engineer will be pleased to give full and frank
may commit errors or omissions in the transfer process. answers to your questions. ,
Although photographic reproduction eliminates this
problem,it does nothing to minimize the possibility of OTHER STEPS YOU CAN TAKE TO
contractors misinterpreting the logs during bid prepara-
tion. When this occurs,delays, disputes and unantici- REDUCE RISK
pated costs are the all-too-frequent result. Your consulting geotechnical engineer will be pleased to
To minimize the tikelihood of boring log misinterpreta- discuss other techniques which can be employed to mit-
tion,give contractors ready access to the comnlete geotechnica[ igate risk. In addition,ASFE has developed a variety of
engineering report prepared or authorized for their use. materials which may be beneficial.Contact ASFE for a
Those who do not provide such access may proceed un- complimentary copy of its publications directory.
Published by
THE ASSOCIATION
OF ENGINEERING FIRMS
PRACTICING IN THE GEOSCIENCES
8811 Coles�ille Road/Suite G 106/Silver Spring, Maryland 20910/(301) 565-2733
0788;'3M
TABLE OF CONTENTS
E-11069-3
PAGE
INTRODUCTION.................................................................................................
1
General ........................................................................................................
1
Project Description ....................................................................................... 1
SITE CONDITIONS .............................................................................................
2
Surface .............................................................. .......................................
... 2
Subsurface ...................................................................................................
2
Groundwater.................................................................................................
3
LaboratoryTesting ........................................................................................ 3
DISCUSSION AND RECOMMENDATIONS ............................................................. 3
Generai ........................................................................................................
3
Site Preparation and General Earthwork............................................................ 4
Slope Fill Placement ..................................................................................
6
Foundations..................................................................................................
6
RetainingWalls ............................................................................................. 8
Seismic Design Considerations......................................................................... 9
Slab-on-Grade Floors..................................................................................... 10
�
SiteDrainage .................................................................. .................... 10 N
Excavationsand Slopes................................................................................. 1 1
Utility Trench Backfill........................................................ ........................... 12
Rockeries and Modular Block Walls................................................................. 13
PavementAreas........................................................................................... 13
LIMITATIONS ...................................................................................................
14
Additional Services....................................................................................... 14
Earth Consultants, Inc.
TABLE OF CONTENTS, Continued
E-11069-3
ILLUSTRATIONS
Plate 1 Vicinity Map
Plate 2 Test Pit Location Plan
Plate 3 Typical Fovting Subdrain Detail
Plate 4 Typical Utility Trench Fill
APPENDICES
Appendix A Field Exploration
Plate A1 Legend
Plates A2 through A4 Test Pit Logs
Appendix B Laboratory Test Results
Plate B1 Grain Size Analyses
�
, ;
ti
- ,
�
Earth Consultants, Inc.
Earth Consultants, Inc.
" c;eotecimical��gneer$c'�eobgists&Fi�vironme�ual Scic��tists Established 1975
ConStruGtion Tesying&ICBO i W'ABO litspec[ion Services
October 13, 2004 E-11069-3
KBS III, LLC
12320 Northeast Eighth Street, Suite 100
Bellevue, Washington 98005
Attention: Mr. Curtis Schuster
Dear Mr. Schuster:
Earth Consultants, Inc. (ECI) is pleased to present this geotechnical engineering study
(GES) for the proposed Stone Ridge III residential development, Renton, Washington.
This study presents the results of our field exploration and geotechnical engineering
analyses for the proposed development. Our scope of services for producing this GES
was outlined in our Proposal, PR-11069-3, dated October 6, 2004.
Based on the results of our study, development of the site as planned is feasible from a
geotechnical standpoint. Medium dense to very dense native silty sand with gravel
glacial till soil suitable for support of foundations was encountered at our test pit
locations. Based on the subsurface conditions observed at the exploration sites, it is
our opinion the proposed building structures can be supported on conventional spread
and continuous footings bearing on the medium dense to dense competent native soils
or granular structural fill.
During wet weather conditions, use of the on-site soil as structural fill will be difficult
due to the moisture sensitive nature of the soil. If grading is performed during wet
weather conditions, use of a free draining granular soil may be necessary. Due to the
moisture sensitive nature of the on-site soils, measures to protect exposed subgrade
surfaces may be necessary. Recommendations for site preparation, foundations, site
drainage, and other geotechnical related issues are presented in this GES.
We appreciate the opportunity to provide our services during the design phase of the
project. If you have questions about the content of this GES, or if we can be of further
assistance, please call.
Sincerely,
EARTH CONSULTANTS, INC.
Raymond A. Coglas, P.E.
Manager of Geotechnical Services
RAC/ddw
1805136th Place N.E.,Suite 201,Bellevue,WA 98005 Other Locations
Bellevue(425)643-3780 FAX(425)746-0860 Toll Free(888)739-6670 Fife
GEOTECHNICAL ENGINEERING STUDY
STONE RIDGE III RESIDENTIAL DEVELOPMENT
148T" AVENUE SOUTHEAST NEAR
STATE ROUTE 900
RENTON, WASHINGTON
E-11069-3
INTRODUCTION
General
This report presents geotechnical recommendations for the proposed Stone Ridge III
residential development, 148th Avenue Southeast near State Route (SR) 900, Renton,
Washington. The general location of the site is shown on the Vicinity Map (Plate 1).
The approximate locations of our test pits and the approximate limits of the property
are itlustrated on the Test Pit Location Plan, Plate 2. Our scope of services included a
subsurface exploration to characterize soil conditions at the site, and preparation of this
report with geotechnical recommendations for the proposed site development.
Earth Consultants, Inc. (ECI) previously prepared a geotechnical engineering study
(GES) for the adjacent Stone Ridge residential development and we are currently
providing geotechnical services for that project.
Project Description
We understand the Stone Ridge III residential development will include six residential
building lots. We anticipate the building construction will consist of relatively lightly
loaded wood frame construction. Based on experience with similar projects,
anticipated wall loads for the proposed buildings will be in the range of 2 to 3 kips per
lineal foot, column loads in the range of 10 to 12 kips, and floor loads of 150 pounds
per square foot (psf). The proposed site access road will consist of east-west trending
residential road that will provide access to the residences from the adjacent Stone
Ridge development. Based on the existing topography, we anticipate the mass grading
of the site will be relatively minimal, with most lots and access road elevations
following the existing contours as much as possible. Cuts and fills ranging up to
approximately eight feet are anticipated throughout the residential building lots and
access roadways.
We understand stormwater from the Stone Ridge III development will be conveyed to
the stormwater detention pond located in the adjacent Stone Ridge development.
Earth Consulta�ts, Inc.
�
I I
�_�
GEOTECHNICAL ENGINEERING STUDY
KBS III, LLC E-11069-3
October 14, 2004 Page 2
i
If the above project description is incorrect or changes, ECI should be contacted to
review the recommendations in this report.
SITE CONDITIONS
Surface ,
The approximate property limits and proposed lot locations are illustrated on the Test
Pit Location Plan (Plate 2). The subject property is located north of the intersection of
148th Avenue Southeast and SR 900, Renton, Washington (see Plate 1 , Vicinity Map).
Specifically, the subject site is located near the northwest corner of the Stone Ridge
residential plat. The site topography gently slopes to the east with approximately 20
feet of elevation change across the width. Vegetation consists primarily of sparse
evergreen and deciduous trees with a dense understory of forest duff and brush. The
site is currently vacant.
Subsurface �
Three test pits were excavated throughout the proposed Stone Ridge III development.
Please refer to the Test Pit Logs, Plates A2 through A4, for a description of the
conditions encountered at the test pit locations.
The soils encountered at the exploration sites consisted primarily of native silty sand
with gravel (Unified Soil Classification SM). Review of the geologic map for southwest
King County identifies glacial till (Qvt) deposits throughout the site and surrounding
areas. The native soils observed at the test pit locations were generally consistent
with glacial till soil deposits. Underlying the surficial layer of topsoil, medium dense,
brown silty sand with gravel (SM) soil was encountered to depths of approximately
two and one-half feet to four feet below existing grade. Underlying the brown silty
sand soils, dense silty sand with gravel glacial till soil was encountered.
At the time our field exploration was performed in October of 2004, the native silty
sand with gravel soil was in a moist to wet condition, with moisture contents generally
in the range of approximately 6 to 12 percent. The native soils are moisture sensitive,
and will degrade rapidly if exposed to excessive moisture. Moisture contents of the
soil samples collected at the site are recorded on the test pit logs included in Appendix
A of this report.
Earth Consultants, Inc.
GEOTECHNICAL ENGINEERING STUDY
KBS III, LLC E-11069-3
October 14, 2004 Page 3
Groundwater
Groundwater seepage was not encountered at the time of our fietdwork in October of
2004. However, the presence of groundwater seepage should be expected in the
deeper site excavations. Due to the nature of the dense glacial till soils observed at the
test pit locations, we do not anticipate the presence of groundwater seepage will
create significant stability problems in site excavations. The use of sumps during
construction, however, may be necessary, depending on the rate of groundwater
seepage entering the excavation.
The contractor should be made aware that groundwater seepage levels and the rate of
seepage are not static; fluctuations in the level and rates can be expected depending
on the season, amount of rainfall, surface water runoff, and other factors. Generally,
the level and rate of seepage is higher in the wetter winter months (typically October
through May). However, confined zones of groundwater may produce moderate to
heavy groundwater flows year around. '
Laboratory Testing
The results of laboratory tests performed on specific samples are provided in Appendix
B, or at the appropriate sample depth on the test pit logs. It is important to note that
these test results may not accurately represent the overall in-situ soil conditions. Our
geotechnical recommendations are based on our interpretation of these test results.
ECI cannot be responsible for the interpretation of these data by others.
DISCUSSION AND RECOMMENDATIONS
General
Based on the subsurface conditions observed at the test pit locations, development of
the site is feasible from a geotechnical standpoint. The primary geotechnical
considerations related to the proposed development include fill placement and
compaction, and moisture sensitivity of the on-site soils. Preparation of the access
roadway subgrade is also an important geotechnical consideration.
Earth Consultants, Inc.
GEOTECHNICAL ENGINEERING STUDY
KBS III, LLC E-11069-3
October 14, 2004 Page 4
The proposed single-family residences can be supported on conventional spread and
continuous footings bearing on the medium dense to dense native silty sand with
gravel, or on granular structural fill used to modify existing grades. Based on test pit
data, we anticipate native soils suitable for foundation support will be encountered at
approximately two and one-half to three feet below existing grade throughout the site.
In our opinion, the foundations can be supported on granular structural fill in areas
where fill is to be placed to achieve foundation subgrade elevation. Recommendations
for structural fill placement are provided in the Site Preparation and General Earthwork
section of this report.
The slab-on-grade for the single-family residences can be supported on the medium
dense to dense native soils or on a granular structural fill. Recommendations for slab
subgrade preparation are discussed in the Slab-On-Grade Floors section of this report.
As previously mentioned, due to the moisture sensitive nature of the onsite soils, and
the potential for groundwater seepage entering excavations, measures to protect
exposed subgrade surfaces will likely be necessary. Earthwork recommendations and
compaction specifications are presented in the Site Preparation and General Earthwork
section of this report.
This GES has been prepared for the exclusive use of KBS III, LLC, and their
representatives. This study was prepared for specific application to this project only
and in a manner consistent with that level of care and skill ordinarily exercised by other
members of the profession currently practicing under similar conditions in this area. No
other warranty, expressed or implied, is made. We recommend that this geotechnical
engineering study, in its entirety, be included in the project contract documents for the
information of the contractor.
Site Preparation and General Earthwork
Based on our current understanding of the planned development, site grading will
consist of cuts and fills on the order of eight feet or less in the building lots and access
roadways. Erosion control measures during site grading should consist of silt fencing
along the site perimeter and mulching of the exposed earth surfaces, as necessary.
Earth Consultants, Inc.
GEOTECHNICAL ENGINEERING STUDY
KBS IIi, LLC E-11069-3
October 14, 2004 Page 5
A representative of ECI should observe the ground surface where structural fill, or
foundations are to be placed. Building and pavement subgrade areas that are exposed
to extended periods of precipitation will likely become unstable. If the subgrade soil in
the proposed foundation and pavement areas becomes saturated and unstable,
overexcavation of the unstable soil and replacement with a granular structural fill will
be necessary.
In our opinion, the native silty sand with gravel soils can be considered for use as
structural fill, provided the soil is placed during dry weather conditions, and provided
the moisture content of the soil is at or near the optimum moisture content at the time
of placement. Aeration and moisture conditioning of the soils may be necessary. The
underlying native silty sand with gravel was in a moist to wet condition at the time of
our field exploration, with moisture contents that were in the range of 7 percent to 14
percent moisture. The native silty sand with gravel soils are moisture sensitive, and
will likely degrade rapidly if exposed to excessive moisture. Moisture contents of the
soil samples collected at the site are provided on the test pit logs included in Appendix
A of this report.
Successful use of the native soils as structural fill may require moisture conditioning
and aeration of the soils prior to placement. Soil stockpiles should be covered with
plastic sheeting during wet weather conditions. The entire stockpile down to the toe
of the pile should be covered with the plastic sheeting.
Imported soil intended for use as structural fill should consist of a free draining, well-
graded granular soil with a moisture content that is at or near optimum, and having a
maximum aggregate size of four inches. The imported soil should have no more than 5
percent fines passing the No. 200 sieve based on the minus 3/4-inch fraction. During
periods of extended dry weather conditions, use of a granular soil with less than 30
percent fines can be considered. Samples of imported soil should be submitted to ECI
for sieve analysis testing.
Structural fill is defined as compacted fill placed under foundations, roadways, slabs,
pavements, or other load-bearing areas. Structural fill under slabs and footings should
be placed in horizontal lifts not exceeding twelve (12) inches in loose thickness and
compacted to a minimum of 95 percent of its laboratory maximum dry density. The
maximum dry density should be determined in accordance with ASTM Test Designation
D-1557 (Modified Proctor).
Earth Consultants, Inc.
GEOTECHNICAL ENGINEERING STUDY
KBS ill, LLC E-11069-3
October 14, 2004 Page 6
The fill materials should be placed at or near the optimum moisture content. Fill under
pavements and walks should also be placed in horizontal lifts and compacted to 90
percent of the maximum dry density except for the top twelve (12) inches, which
should be compacted to 95 percent of the maximum dry density.
Slope Fill Placement
Placement of fill on existing sloping grades may be necessary at some locations
throughout the site. In our opinion, the placement of fill on slopes is generally
acceptable. However, where the existing slope grade exceeds 15 percent, the fill should
be keyed and benched into the slope.
This process consists of excavating a keyway at the toe of the planned fill. The keyway
should have a width of approximately six to eight feet and a depth of two feet into
medium dense to dense native soil. The slope above the keyway should then be cut into
a series of horizontal to slightly inward sloping benches. Typically, the benches are
excavated with a bulldozer as the fill is placed in lifts and compacted.
Foundations �,
In our opinion, the proposed residential structures can be supported on conventional
spread and continuous footings bearing on the medium dense to dense native silty sand
with gravel, or granular structural fill. As previously mentioned, we estimate
competent native soils suitable for support of foundations should be encountered at
depths of two and one-half to three feet below existing site grades.
For foundations bearing on the medium dense to dense native silty sand with gravel or
granular structural fill, an allowable soil bearing capacity of two thousand (2,000) psf
should be used to design the foundations. This allowable soil bearing capacity has a
factor-of-safety in excess of 3.0 against shear failure, provided the foundations are
placed on competent native soils or granular structural fill. A one-third increase in the
above allowable soil bearing capacity can be assumed for short-term wind and seismic
loading conditions. Continuous and individual spread footings should have minimum
widths of eighteen (18) and twenty-four (24) inches, respectively.
Earth Consultants, tnc.
it
GEOTECHNICAL ENGINEERING STUDY
KBS III, LLC E-11069-3
October 14, 2004 Page 7
If loose or unstable soil conditions are encountered at the footing subgrade elevation,
the soil will need to be overexcavated, and replaced with granular structural fill. The
width of the overexcavation should extend a minimum of twelve (12) inches beyond
each edge of the foundation. As previously discussed, care will need to be taken to
protect and preserve exposed subgrade surfaces to limit the amount of disturbance to
the subgrade, and to limit the need for overexcavation. If necessary, to help protect
and preserve exposed foundation subgrade surfaces, two inches of crushed rock can
be placed as a working surface along subgrade surfaces.
Exterior foundations elements should be placed at a minimum depth of eighteen (18)
inches below final exterior grade. Interior spread foundations can be placed at a
minimum depth of twelve (12) inches below the top of slab, except in unheated areas,
where interior foundation elements should be founded at a minimum depth of eighteen
(18) inches.
Provided the foundations are placed in accordance with the recommendations
contained in this report, we estimate total settlement of approximately one inch and
differential settlement of approximately one-half inch. Most of the anticipated
settlements should occur during construction as dead loads are applied.
Lateral loads can be resisted by friction between the base of the foundation and the
supporting soil, and by passive soil pressure acting on the face of the buried portion of
the foundation. Resistance to lateral loads from passive earth pressures should be
calculated using an equivalent fluid with a unit weight of three hundred fifty (350)
pounds per cubic foot (pcf). To achieve adequate passive resistance, the foundations
must be backfilled with structural fill. As an alternative, the foundations can be poured
neat against the undisturbed native soil. For frictional capacity, a coefficient of 0.40
should be used for foundations bearing on competent native soils or granular structural
fill. These lateral resistance values are allowable values; a factor-of-safety of 1 .5 has
been included.
Footing excavations should be observed by a representative of ECI prior to placing the
formwork and rebar. ECI should also perform compaction testing of structural fill and
observe areas where overexcavation is required to remove loose or unstable soils.
Earth Consultants, Inc.
GEOTECHNICAL ENGINEERING STUDY
KBS III, LLC E-11069-3
October 14, 2004 Page 8
Retaining Walls
Retaining walls should be designed to resist lateral earth pressures from the retained
soils, and any surcharge loading. Walls that are unrestrained and free to move at the
top should be designed using an equivalent fluid with a unit weight of thirty-five (35)
pcf. The earth pressure imparted on restrained walls should be calculated using an
equivalent fluid with a unit weight of fifty (50) pcf. The above equivalent fluid values
assume surcharges due to traffic, sloping backfill, adjacent foundations, construction
loads, or any other loadings will not apply. If surcharges are to apply, they should be
added to the above design lateral pressures. Where drainage behind retaining walls
cannot be accomplished, hydrostatic pressures should be added to the design wall
pressures, where appropriate.
For traffic surcharge loading consisting of passenger vehicles or light delivery trucks, a
uniform pressure of seventy (70) psf should be applied in a rectangular distribution
along the height of the retaining wall. Where traffic surcharge loading from heavy
trucks will be present, ECI should review the wall and roadway configuration and
provide modified surcharge values, if necessary. If sloping backfill conditions are
present behind the walls, ECI should review the slope configurations and provide
modified equivalent fluid values, as necessary.
Retaining and foundation walls should be provided with a four-inch diameter perforated
drainpipe and backfilled with a free-draining granular soil with less than 5 percent fines
(percent passing the No. 200 sieve based on the minus 3/4-inch fraction). The zone of
free-draining granular soil should extend along the entire height of the wall, and a
distance of at least eighteen (18) inches behind the wall. A surface seal consisting of
a less permeable silty sand soil can be placed along the upper one foot of the wall
backfill, if desired. The remainder of the backfill behind the zone of free draining soil
should consist of a suitable granular structural fill.
Earth Consultants, Inc.
GEOTECHNICAL ENGINEERING STUDY
KBS III, LLC E-11069-3
October 14, 2004 Page 9
Seismic Design Considerations
The largest earthquakes in the Puget Sound region have been subcrustal (intraplate)
events, ranging in depth from fifty (50) to seventy (70) kilometers. Such deep events
have exhibited no surface faulting. Weaver and Shedlock (1989) researched the
probable or known source areas for the crustal, intraplate, and subduction zone
earthquakes in the Washington and Oregon area. Crustal and intraplate earthquakes I
are the only events in Washington and Oregon in which there is a historical record.
Shallow crustal earthquakes occur within the North American Plate, and typically do
not exceed focal depths of approximately 20 kilometers. Intraplate earthquakes occur
in the subducting Juan de Fuca plate, and typically occur below depths of 40
kilometers. The recent February 28, 2001 , earthquake that was focused just north of
Olympia, Washington was an intraplate earthquake, and had a magnitude of 6.8. The
subduction zone earthquake, in which there is no historical record in the Washington
and Oregon area, would have its source along the interface between the North
American Plate and the subducting Juan de Fuca Plate. Magnitude 8.0 or more
earthquakes are thought to be possible along this interface, and would occur at depths
of approximately 50 to 60 kilometers (Weaver and Shedlock, 1989).
The Uniform Building Code (UBC) and International Building Code (IBC) Earthquake
regulations have established a series of soil profile types that are used as a basis for
seismic design of structures. Based on the encountered soil conditions, it is our
opinion that soil type Sc from Table 16-J of the 1997 UBC should be used for design.
For IBC based design, Site Class C from Table 1615.1 .1 of the 2003 IBC should be
used.
Liquefaction is a phenomenon in which soils lose all shear strength for short periods of
time during an earthquake. The effects of liquefaction may be large total and/or
differential settlement for structures with foundations founded in the liquefying soils.
Groundshaking of sufficient duration results in the loss of grain-to-grain contact and
rapid increase in pore water pressure, causing the soil to behave as a fluid for short
periods of time.
To have potential for liquefaction, a soil must be cohesionless with a grain size
distribution of a specified range (generally sands and silt); it must be Ivose to medium-
dense; it must be below the groundwater table; and it must be subject to sufficient
magnitude and duration of groundshaking.
Earth Consultants, Inc.
,
GEOTECHNICAL ENGINEERING STUDY
KBS III, LLC E-11069-3
October 14, 2004 Page 10
Based on the soil and groundwater conditions observed at the site, it is our opinion that
the site has a low susceptibility to liquefaction. The dense condition of the native soils
and lack of a shallow groundwater table are the primary bases for this conclusion.
Slab-on-Grade Floors
Slab-on-grade floors should be supported on competent native soils or granular
structural fill. Loose or unstable subgrade soils should be stabilized prior to
construction of the slab. Fill areas will be particularly susceptible to disturbance during
wet weather conditions. Care will need to be taken to preserve the integrity of the
subgrade soils, particularly during the installation of the under slab utilities. If the
construction is performed during the drier summer months, measures to preserve the
subgrade soils will likely be minimal. During periods of wet weather, however, a free
draining structural fill may need to be utilized throughout the upper twelve (12) inches
of the building pad to help preserve the integrity of the subgrade.
A minimum four-inch capillary break consisting of a free draining, poorly graded gravel
with less than 5 percent fines (percent passing the No. 200 sieve, based on the minus
3/4-inch fractionl should be placed below the slab. A vapor barrier consisting of a
minimum 6-mil plastic membrane should be placed above the capillary break. To aid in
curing of the concrete slab, two inches of sand can be placed over the plastic
membrane.
A representative of ECI should observe the subgrade soils in slab-on-grade areas of the
site prior to placing the capillary break material.
Site Drainage
During construction, surface water runoff must not be allowed to stand in construction
areas. Interceptor trenches should be established, as necessary, along the perimeter of
the building site to intercept surface water runoff or groundwater before it enters the
construction area. During construction, loose surfaces should be compacted to reduce
the potential for moisture infiltration into the soils. Finish grades around the buildings
must be sloped such that surface water is directed away from the buildings.
Earth Consultants, Inc.
GEOTECHNICAL ENGINEERING STUDY
KBS Ili, LLC E-11069-3
October 14, 2004 Page 1 1
Footing drains should be installed around the perimeter foundations to intercept
groundwater seepage. A typical perimeter footing drain detail is illustrated on Plate 3.
Under no circumstances should roof downspout drain lines be connected to the footing
or foundation wall drain systems. All roof downspouts must be separately tightlined to
the site stormwater system.
In the deeper site excavations, such as utility installations, the presence of
groundwater seepage should be expected, particularly if the excavation is performed
during the wet season. Due to the generally dense condition of the glacial till soils
observed at the test pit locations, we do not anticipate the groundwater seepage will
create a stability problem. However, measures to intercept the groundwater seepage
and direct it to an appropriate discharge location may be necessary.
Excavations and Slopes
The following information is provided solely as a service to our client. Under no '
circumstances should this information be interpreted to mean that ECI is assuming
responsibility for construction site safety or the contractor's activities; such
responsibility is not being implied and should not be inferred.
In no case should excavation slopes be greater than the limits specified in local, state,
(WISHA) and Federal (OSHA) safety regulations. Based on the information obtained
from our field exploration, the upper deposits of inedium dense, silty sand with gravel
that extends to a depth of approximately three feet below existing site grades, would
be classified as Type C soils by WISHA/OSHA. Temporary cuts in Type C soils should
be sloped at an inclination no steeper than 1 .5H:1 V, (Horizontal:Vertical) respectivety.
The unweathered glacial till observed below a depth of approximately three feet would
be classified as Type A and Type B soils by WISHA/OSHA. Temporary slopes
constructed in Type A and Type B soils should be inclined no steeper than 0.75H:1 V
and 1 H:1 V, respectively. ECI should observe the excavations to assess soil and
groundwater conditions, and to verify the WISHA/OSHA soil type.
Permanent cut and fill slopes should be inclined no steeper than 2H:1 V. Cut slopes
should be observed by ECI during excavation to verify that conditions are as
anticipated. Supplementary recommendations can then be developed, if needed, to
improve stability, including flattening of slopes or installation of surface or subsurface
drains. In any case, water should not be allowed to flow uncontrolled over the top of
slopes.
Earth Consultants, Inc.
GEOTECHNICAL ENGINEERING STUDY
KBS III, LLC E-11069-3
October 14, 2004 Page 12
Permanently exposed slopes should be seeded with an appropriate species of
vegetation to reduce erosion and improve stability of the surficial layer of soil.
Utility Trench Backfill
Based on the soil conditions encountered at the time of our exploration, the native soils
should provide adequate support for utilities. If remedial measures are necessary to
provide adequate support for utilities, the unsuitable soils should be overexcavated and
replaced with a suitable structural fill material.
In our opinion, the native silty sand with gravel soils can be considered for use as
backfill for the utility trenches, provided the soil moisture content is at or near its
optimum level. As previously mentioned, the native soils were generally moist to wet,
and had moisture contents that were near or above optimum levels. Some moisture
conditioning of these soils may be necessary prior to use as structural fill in the utility
trenches. �
Due to the moisture sensitive nature of the native silty sand with gravel soils,
placement, and compaction of the soil will need to be performed during dry weather
conditions. To protect the soils from wet weather conditions, soil stockpiles should be
covered with plastic sheeting. The plastic sheeting should cover the entire stockpile.
Due to the moisture sensitive nature of the native silty sand with gravel soils, the upper
twelve (12) inches of the trench backfill in building and pavement areas may become
disturbed if exposed to wet weather conditions and construction traffic. Construction
traffic should be kept to a minimum along utility trench alignments where backfilling
and compaction have been completed. As an alternative, free draining gravel can be
used to backfill the upper twelve (12) inches of the trench excavations to provide a
wearing surface, and to help protect the underlying moisture sensitive backfill. Use of
a free draining backfill along the upper twelve (12} inches of the trench excavation
would likely only be necessary if construction is performed during the wet season.
Utility trench backfill is a primary concern in reducing the potential for settlement in
pavement areas. It is important that the utilities be adequately supported in the
bedding material. The material should be hand tamped to ensure support is provided
around the haunches of these structures. Fill should be carefully placed and tamped to
about 12 inches above the crown of the pipe before heavy compaction equipment is
brought into use.
Earth Consultants, Inc.
GEOTECHNICAL ENGINEERING STUDY
KBS III, LLC E-11069-3
October 14, 2004 Page 13
I
The remainder of the backfill should be placed in lifts having a loose thickness of less
than twelve (12) inches. A typical trench backfill section and compaction requirements
for load supporting and non-load supporting areas is presented on Plate 4. It is
important to note that local utility districts may have compaction requirements that
supersede those presented on Plate 4.
Rockeries and Modular Block Walls
In our opinion, the use of rockeries or modular block walls at the site is feasible from a
geotechnical standpoint. If rockery or modular block walls are utilized, an engineered
design will need to be completed for rockeries and walls that exceed four feet in
height. ECI can provide an engineered design for the site, if requested. At a minimum,
ECI should review the layout of the proposed walls and the proximity of roadways and
foundations to the walls. Supplement geotechnical recommendations can then be
prepared, if necessary, to address wall design and surcharge loading.
Pavement Areas '
The adequacy of site pavements is related in part to the condition of the underlying
subgrade. To provide a properly prepared subgrade for pavements, the subgrade
should be in a firm and unyielding condition when subjected to proofrolling with a
loaded dump truck. Structural fill in pavement areas should be prepared as described in
the Site Preparation and General Earthwork section of this report. This means the
pavement subgrade should be compacted to at least 95 percent of the maximum dry
density in structural fill areas. It is possible that some localized areas of soft, wet or
unstable subgrade may exist after the pavement subgrade is prepared. Overexcavation
and a greater thickness of structural fill or crushed rock may be needed to stabilize
these localized areas.
Assuming a properly prepared subgrade that is in a firm and unyielding condition when
subjected to proofrolling, the following pavement section for lightly loaded areas is
suggested:
• Two inches of asphalt concrete (ACy over four inches of crushed rock base
(CRB) material, or
• Two inches of AC over three inches of asphalt treated base (ATB) material.
Earth Consultants, Inc.
GEOTECHNICAL ENGINEERING STUDY
KBS III, LLC E-11069-3
October 14, 2004 Page 14
Heavier truck-traffic areas will require thicker pavement sections depending upon site
usage, pavement life, and site traffic. As a general rule, the following sections are
suggested for truck-trafficked areas:
• Three inches of AC over six inches of CRB, or
• Three inches of AC over four and one-half inches of ATB.
AC, ATB, and CRB materials should conform to WSDOT specifications. All rock bases
should be compacted to at least 95 percent of the maximum dry density.
LIMITATIONS
Our recommendations and conclusions are based on the site materials observed,
selective laboratory testing and engineering analyses, the design information provided
to us, and our experience and engineering judgement. The conclusions and
recommendations are professional opinions derived in a manner consistent with that
level of care and skill ordinarily exercised by other members of the profession currently �,
practicing under similar conditions in this area. No warranty is expressed or implied. �
The recommendations submitted in this report are based upon the data obtained from
the test pits. Soil and groundwater conditions between exploration sites may vary
from those encountered. The nature and extent of variations between our exploratory
locations may not become evident until construction. If variations do appear, ECI
should be requested to reevaluate the recommendations of this report and allowed to
modify or verify our recommendations in writing prior to proceeding with the
construction.
Additional Services
We recommend that ECI be retained to perform a general review of the final design and
specifications to verify that the earthwork and foundation recommendations have been
properly interpreted and implemented in the design and in the construction
specifications.
Earth Consultants, Inc.
GEOTECHNICAL ENGINEERING STUDY
KBS III, LLC E-11069-3
October 14, 2004 Page 1 5
We also recommend that ECI be retained to provide geotechnical services during
construction. This is to observe compliance with the design concepts, specifications or
recommendations, and to allow design changes in the event subsurface conditions
differ from those anticipated prior to the start of construction. ECI should be retained
to review the construction drawings and specifications, and to provide construction
observation and testing.
Earth Consultants, Inc.
Q -
SE,q.N HAZfU�OD � 73RD PL ,,��oQ��SF.�t� � w = m yL - C S
5 p�r,.y, ¢ :� P�a y ti H �F � `= , ��T f 1'�� � � � �, � CtUB
c, � � y�a
a ,��, ��N�, acr�,`� �<' 'kS ,4�y, J�s�,'r,°<�.. 5 �? Sf�� � � � r �_ Ar I
TH_ Y ST � c -� s, °� sf_ q r� rn 5,. ..
SE �.;i SE7 ... .� S'pl! F�-�"�v-T.-��5, y- � �5.... �. SC7fiA1Dl
�bni ci -_ " srs sc a _ r-�F' S < �y NfWCASTLf
' -�� Pi� �� � N pt`�a -._ SE� i F .rF SE 77TH PL
_ �
� SE 75TH PL ` Sf a
. �
:�c ^ .f„ 76TH P� � LAKE � �t .�� �b7H vl
> 1 --
5(�1]! �Y-X �} ))iN Pl. �. , $E � �u S
�� � ?F �rl Sf-�BTy r 7� vL mS� N ���-.°<�ej�' � BDRF r cr�` ti���S�� ,c�*�t
SE 90TH 9TN ST " ST +� _ ��� � �'� � �Ty:% �n< y`�^ �Ty r.V SW SF l9�ya�z ,����1 H �
� �
- U� 9� � '��sr E�5`° �'Y N �f j� 139TH AVS4' � �SSE 787�r�M'��'4 sF�9,N tt
; ^ �'` • m P� �� m BORfN � ,- j stsja�'�z,S 79SH T Y`p��TM' 4h a�1/f
� azno = w.. � -i s 4 � Trv � a s
I SF � N �� � �a � < ` PARK y� �.r Ty SF. ly4 AV u �aar+ ; Pi �.�
��"\ T
TH � $E _..- '�n 5T . CT = x SF BarN� S(�,�j-�MV"�$`' ^J��p ���� S7 y94 vlH
� �
T =.a _ _ -.._ �....F.. -. T . �""� $tY� �~.. .4 . ..... . , f'.
J_ �
i � :t � ��E eSTH .� � �5� -� r ���1 s���.:�:.
� � � E-i�l tl >� c` .
� � � S SS �
j {� " P.SE 85T}. " d� � (� c'lf . x C7 �Ct� !oE
� 'c y � � �E 1�;_ .�.� �f+ g� , SF ,.e 0 %_,i�O(lCAft �
^ s�L Pecnr sc Sa�n{ , ,y s a'A i.�. ��C�y�g'��` �� s N � '" FKXIMAIN'
� SE 88TH s «ST ''` RE610NAL `
ifY \C,
3 L�� v� ��=�� a F o 5�s•
i", s S - , _. s , y� � . � ,. Q� sc < STH 95 ,
� N �� ~ - E c� 9 4, earii � Pt< WILDLAND
+!�.�5� ti y�'.$�8 9 T H .S T . ��P g � " rH P ' f. �9� !"��,� � i ��'.fl S SE 86P�.m rAF;R L
�h:���ac5�2Q,�:. � 90TH ST � � � � o S� 9� c s~ af B�rH
.t � oa [u+onih'. SE 915T+ ST� FLIY , 9 �st F` � I (
_ _. :F,� r o i4:: m �
� P` Au I� - 92N0 5 s:.., CRfFk" \ . �, `[ '__ '�p � ��
3�
� � S`� � � hw _° P�4RK �� `� Y ;t� 9isr ��r� � �`
_ ---- i. s
31�r I, ^"' � h4 - � W� s��'' SE. yo �
ST =a e � -- ,. V � SE 3RD
, Sf= 9�p 5� � = � N'� SF�--•,. >SE �� ST ST
� gSTN 6 .,; Z '9S p Y T'24NAL L f Y �
_,a�� -�."��� � ���vi—- � �9 c� � --
9 "�" 57 \ MAY 5E �a ' � ''�— --- iau��"--��
�-�'�� : �� " . < � _ '�- 3N __
�
� � _
vrH sT �°�� l � __
kE '� ��'`'- s� � �SIER6;4 NE 2JT1f �z > i- �
z 277y``,, = z�� � � z P�_� ` I` �
� �C `'� S` �ST' NP� + ~25TH PL �:nrH y: a � ��sm.�'
Z O NE�
K�YA4LE z W x 75'�+.- �� 'u' .. s��KE 100TH _ ST �- Z o �s�'z NE 2 �T �. I
�" �'fz5��o _ = T jf � � '�-- s[ ioorn �a � �SE fOCTa
.- W >
PARX ,4.�P4TF! S� g7 3= , sr ��'� . ��" �, `�{w -ir�ISF 5�NE> �"24TH_:SE IOOTH S� .SE -- 100TH y7 �
�, �,� �: _u, m ST;uirv P.imc Pl Y i_. - rt��L7I
NE a�a���'�p�� < �\\ �� 1 � SE -= '.02ND ST `= MF 23im xE z3F1� �'`..73NQ-—� a � c
{IlI 2 S = �- e��� � <' L _ �a ^z R sr I,a � .i��ti -3o sE yczrw:-
23RD S {;t 1 i� ' i ^ �` � � c NE 22��D ST � y�� � NE ��'�E � �`` �� " f
,i w= W = S� NE 22N0 ST �� � Q $ �". NE- ��21ST ST r J� ,. �22�PL a , < s a's'��sT� y�cr
o : � ti
-= ¢ .•:.�a ��.. ... = : o � �n w[zcrx�Q Q NE 21Sr :ts-9� - � �G i �� o Ri ^`�
?ir sr: � l z;,, � . z Pl "��J 3 1E a' z:s� �
g NE �NE I9 pTM S' cj 1
`a ST c' o NE :�lH 5i `�e+'r � �'s<w N11AlEY.CREEK� : . � �5�� Z 20TH- ST TN ST v� �F. .o �E lha-Si
� 1„�OPEN E L �a �¢ _.-1gTH ST `rt�9`"y sr i
q xE ;vrH sr , � 3 NE '- �� � ` J� N N�
o � y . .�� m h� ,� Q w SE 105T 1
u hUR7Ft�� � � K em� . � �r'�'n �3 tFi� >.� z i � .,.
, � !BFH S� Y ��tANL$ Q :811 S'( � HE i7Ty p �r,n�, ,�lSM1% � `p?1� —ST O,zi�n Q <Fl0 �� ■ `�
� �� o '�"` z 1 �`�. � `,. � ;- � d,,,� .. yF� i 5
� m � � �:Ja. NE... � � o ..._ s= � - .. �. NE I7TH ST ��� _" ■ia:��o�o � �H SE 101Th P��,�. lP
�u W � <Z� e� < �: UNSE7"` .� :�. $�
6 � s r �tio << �� � -o � a
� `S a 2 Y - � a i �c�2- Q � W Q�VO •11 � �s
Q g �lA`H > x=p � NC'4TH k i ��E i<M k � V .
m 5' s� MID Q z W '� sT u ewc iatH< sT�T x�;.r � `fc�' �,w
�� '�E 13TH PL 2 f ' H 5 t� N� 13T��ST ¢q = g ^:E�anc ___-. W � a' � �
€ m 3� xE 13SLIB"' (V � �'� E . � q`F i '�Cn �N�A
I 2TH 5T �o � NE � ' � 12TH ��� 6 ST h: � __ . � � �1-p� SSP �
_��n, � sE i i2 �' sr N 1 �.:
� z �r- � « _ = sr � �"" z:;,;
K ��D � .�o RJi. _- i � = P� � < z'W '" _
R = v,we i�¢ q7 �} hE ..'H N, Hi 1liH �; I z OCIVFR M z s_ 1� c�
�'�'$' � � f,' .`h " Si NAZfN
� ��s �s� z HE �;ia <r � �liy , �
� � r�k � � r '� �__ _ , HS ¢ — " _ ,
aT �rnt H� a i - �
I � = o5uca c ME 10?N P�_a . . , '_ � -. _— _ ., -
:�I�,tVYI �z �� 7 � H
i
I
Earth Consultants, [nc.
Ref@rellC@. � Grutechnical Fn��ineerin,^,.Geolo��y.Enriron�nrn�al ticirn��rs
Kll�g COUI�ty G>nshiKYi��n Tc�stin��&ICBU l��'ARO Inspr['ticm tic n�irrs
Map 626
By Thomas Brothers Maps ViCinity Map
Dated 2005 Stone Ridge III
King County, Washington
NOTE: This plate may contain areas of color.
ECI cannot be responsible for any subsequent Drwn. GLS Date Oct. 2004 Proj. No. 11069-3
misinterpretation of the information resulting Checked SSR Date 10/14/04 Plate 1
from black&white reproductions of this plate.
/ ,
��� � � __, _
� - - - - - - - - - - - - -/ - - - �/, - - - - - - - - - - - - - - - - - -
i � / / �
-� I
i �'% / � �
, ,
� 2 � � ���� 4 � i
� �
� _ _ _ 1Stone/R�d�.� "�— - - — � I
_�_ 1 � I- � - � �
�TP-1 � � �� _I TP-3 TP-2 v i
I � �� � I � �
I - ���� �i�� „
� i ' W � / i
,�� ! I V � , i
� - - - - - - - - - - - �- �- - - - - - - - -� - - - - - - - - - - - - -� , _
J`, � a ,
r - - - - - - - - - - - - - 1 �—
�I Q i \ 6 i ,
� i �
', � '� ����� ����+ge � � � � � � ��
Y � ,\ � i
` " _ _ - - _ � �` \ ' I
1 � � - ' J
_ , � , �
, -
� �� , � ,
, �� ,
, �
iF�FNn
TP-1—�— Approximate Location of
ECI Test Pit, Proj. No.
E-11069-3, OCt. 2004 Approximate Scale
Subject Site o 3o so 12oft.
Lot Number
Earth Consultants, Inc.
(:e<�trchnic al En��iiterrinh.(:eoloy;}t Ern�ironmrntal scirnc-rs
C<�nstru<�tion Trstin�&ICRO%l�'.�BO Inspe�7ic�n�n9crs
NOTE: This plate may contain areas of color. TeSt Plt LOCatiOtl Plan
ECI cannot be responsible for any subsequent Stone Ridge I I I
misinterpretation of the information resulting
from black & white reproductions of this plate. KI11g COUnty, Washington
I Drwn. GLS Date Oct. 2�04 Proj. No. 11069-3
' � Checked SSR Date 10/14/04 Plate 2
��
�
`_�Slope To Drain . .,. ,� �
.s�,}�j.
- - ••~ ••�• •�i9
�.:.•.�• :• •.:.� :• �..•-�.:• .-
6 inch min. :?:r. ,=r:� : :i: ':;: '. :i;j.: ;r:�:
•:::•��:;;..,,:::ti��:: :;�;::;:r.::i;;;;:;. •.:; •:::.�•..:::
•..� •• . �:�.. ��'. i ' � .'�.1�.'.��� � �� i��'�•l:•�.
...+OS'.ao.7.od-��.. ••�O�1i��LoolS�'-..�0.�•�000
••�o� o O p Oo O� ��o�o O p Oo O� ��o�o O p Oo
o�o 0��00o��o4io o���oo��°�Oo o��� 18inch I
o �° ° � ° o °° ° �° o °oo min.
00�o��o°o o° °�000°�0��00 � ��oo�°oo 0
0 0 0 0 0 0 0 0
0�00�000° � 0 o�O��o00° � � o�0o0a
00 o pp o 00 0 � � o0 o p
� p oo °O � a p oo � O � � p o0
000 000°oa�oo ° o00 $oa°ao�oo ° aoo go
0 00 ° o 00 ° o
4inchmin. °o°000 00 0 0000000 00 0 00000
° a o ° o 0 0 0 � o ° a
Diameter o000 0°�°00$00 0 000 00 0 0 0 0 0
Perforated Pipe o o�°o 0 0 o ao�o�°o�
Wrapped in Drainage
�oo o a0000 �a o�oo o °o
Fabric °o°� � ° �°�o°°� o
�o 0 0 � o
Oo 8�0�0 �
0 0
O V �
r
_ n
I 2 inch min. '
2 inch min. /4 inch max. �
12 inch
min.
iFrFNn ,
f Surface seal; native soil or other SCHEMATIC ONLY- NOT TO SCALE
��ti: low permeabitity material. NOT A CONSTRUCTION DRAWING
o°°0
o°�° 1"Drain Rock
0 00
Drain pipe; perforated or slotted rigid
Q PVC pipe laid with perforations or i Earth Consultants, Inc. ��
slots facing down• tight jointed• with a ��e�����,�,�«�E„���,ee�,.�ow�ists x Em•iram�ental Scienu<ts
Conctrucfion TestNl,.^,A ICBO!\t'ABO Inyxr7ion Serrices
positive gradient. Do not use flexible
corrugated plastic pipe. Do not tie NpICAL FOOTING SUBDRAIN DETAIL
building downspout drains into footing
lines. Wrap with Mirafi 140 Filter Fabric Stone Ridge III
or equivalent. King County, Washington
Drwm. GLS Date Oct.2004 Proj. No.11069-3
Chedced SSR Date 10/14/04 Plate 3
� I�
I I��
Non-Load Supporting Floor Slab or
� Areas Roadway Areas
:':�'�' ���� i
� �" '� -= Varies
; ::r�;;:;:;:';��;; o op o o�oo 0
��' :85: '':'' �o 0 0�° 5 � o 0
.;,.
'::: �;:;;::� 5 .�-:�f..,•. 1 foot min.
': ••' ::•-:� •���:�,..�r�
i: •;'s7 •�i: ;�_;: ;�:� :.
� .[�,`� ��`�•�� ����'!• ��.
Backfill : :.:�:' ':::::�: �::;;• ::�;.::: ::°
AY♦'�� �ll�} . �•f1 �•ll�j��• �J�
j. � . ::,,�.�:.�:.�� ..... : -;�,��•��.�
'� �ti.• �'�� .. . '
I :y; ..'�. •,90..;:.h:::;c;:•.
";� �;�: ':.�.? Varies
:�: :••� ::;:,: • :•. :;.
i: :• :t� �:tir: ,�, :i;::;�•
:.y' .: ,ti�'�'•
'�i; �';' :��;.
,:� ;r. ;•ti� ;y;}�!;
. ;;:::': ; ::,:::: Pipe ';:�:�:::=.:::_ :;�.
ooQd'EiO��o� .6:°S��o•••d�d
o� �Q��o. • ��Q'���° .o
'0 a��,bn•`.�J°�. o'��t:oo�"Vo� C'
d: o'. o: o:'• ',�o;. 'o,'�,���'..
Bedding eQao.��Q.o Q:ao. o.o Qao.�b-�.o,�. Varies
•.�Qb�'���.,�Q��e'��.,�Qb�o'���.,�Q�
o•
'a,p o�d:°a�o�'�d�°��oo0'wd:;Sb'Qoup:$6
o :p.;Qo :p.,Qe :p. '.
iF�FNn
- Asphalt or Concrete Pavement
or Concrete Floor Slab
Base Rock or Capillary B�eak, SCHEMATIC ONLY-NOT TO SCALE
�o��� as Appropriate NOT A CONSTRUCTION DRAWING '
� Backfill; Compacted On-Site Soil
�''"'' or Suitable Imported Fill Material
; Minimum Percentage of Maximum
Laboratory Dry Density as determined
90 by ASTM Test Method D 1557-91 i Earth consultants, 1C1C.
Geo�echnical En�neers.Geolofiists&Em�ironmental Sclen�ists
(Modified Proctor), unless otherwise <�,,,.«,K��o�,Te.;,;,,�h,�6�!„.�H�,,,�„��,;o„�P�,.;�P�
specified in the attached report text.
TYPICAL UTILITY TRENCH FILL
�oo o Bedding Material; material rype depends Stone Ridge III
�• � on type of pipe and laying conditions.
Bedding should conform to the King COU�ty, Washington
manufacturers recommendations for the
type of pipe selected. Drvm. GLS Date Oct. 2004 Proj. No. 11069-3
Checked SSR Date 10/14/04 Plate 4
APPENDIX A
FIELD EXPLORATION
E-11069-3
Earth Consultants, Inc. (ECI} performed field exploration on October 8, 2004.
Subsurface conditions at the site were explored by excavating three test pits
throughout the site. The approximate test pit locations were determined from existing
landmarks presented on available plans. The locations of the test pits should be
considered accurate only to the degree implied by the method used. These
approximate locations are shown on the Test Pit Location Plan, Plate 2.
The field exploration was continuously monitored by a geologist from our office, who
classified the soils encountered and maintained a log of each test pit, obtained
representative samples, measured groundwater levels, and observed pertinent site
features.
All samples were visually classified in accordance with the Unified Soil Classification
System that is presented on Plate A1 , Legend. Logs of the test pits are presented in
Appendix A, Plates A2 through A4. The final logs represent our interpretations of the
field logs and the results of the laboratory tests of field samples. The stratification
lines on the logs represent the approximate boundaries between soil types. In
actuality, the transitions may be more gradual.
�
II
J
j �
, i
�_ ,
� �� �
;
i
Earth Consulta�ts, Inc.
MAJOR DIVISIONS GRAPH LETTER TYPICAL DESCRIPTION
ISYMBOL SYMBOL
GN/ Well-Graded Gravels,Gravel-Sand
Gravel 4 o Q e a o g�y Mixtures, Littie Or No Fines
And Clean Gravels
Gravelly (little or no fines) r ` GF1 Poorly-Graded Gfavels,Gravel-
Coarse Soils • • ■
Grained � � � gp Sand Mixtures, Little Or No Fines
Soils More Than �'jM Silty Gravels,Gravel-Sand-
;50% Coarse Gravels With gm Silt Mixtures
Fraction Fines(appreciable
Retained On amount of fines} G(; Clayey Gravels,Gravel-Sand-
No.4 Sieve 9C Clay Mixtures
Sand , �o 0 0 �o SW Well-Graded Sands, Gravelly
And Clean Sand o o � o o SW Sands, Little Or No Fines
Sandy (little or no f ines) q;a �,.;
More Than Soils o ; � : �P Poorly-Graded Sands, Gravelly
50g Material A Q'��'9<':' Sp Sands, Little Or No Fines
Larger Than More Than
No.200 Sieve 50°6 Coarse ' SM Silty Sands, Sand- Silt Mixtures
5ize Fraction Sands With Slll
Fines(appreciable
S eveng No.4 amount of fines! SC Clayey Sands, Sand-Clay Mixtures
SC
I I I I .. � ML Inorganic Silts 8 Very Fine Sands,Rock F�o�r,Silty-
rp� Clayey Fine Sands;Clayey Silts w/Slight Plasticity
Fine Silts I Inorganic Clays pf Low To Medium Plasticity,
Grained qy�d Liquid Limit C�,
Soils Clays Less Than 50 � C� Gravelry Clays, Sandy Clays, Silry Clays, Lean
� I � I � � �L Organic Silts And Organic
� I � I � I O� Silty Clays Of Low Plasticity
1�I MH inorganic Silts,Micaceous Or Diatomaceous Fir�
More Than � mh Sand Or Silty Soils
50% Matenal gilts
Smaller Than And Liquid Limit CH Inorganic Clays Of High
No.200 Sieve Clays Greater Than 50 Ch Plasticiry, Fat Clays.
Size �/// //
��/�� ��"� Organic Clays Of Medium To High
Ofl Plasticity, Organic Silts
`��� �"� �"� pT Peat, Humus, Swamp Soils
Highly Organic Soils
, ,�i, ��r, ��r pt With High Organic Conten.ts
Topsoil 'y'�'y'�'J Humus And Duff Layer
Fill Hiyhly Variable Constituents
The discussion in the te�of this report is necessary for a proper understanding of the nature
of the material presented in the attached logs.
DUAL SYMBOLS are used to indicate borderfine sal classification.
C TORVANE READING,tsf I 2"O.D.SPLIT SPOON SAMPLER
qu PENETROMETER READING,tsf
W MOISTURE, %dry weight � 24"I.D. RING OR SHELBY TUBE SAMPLER
P SAMPLER PUSHED
* SAMPLE NOT RECOVERED i WATER OBSERVATION WELL
pcf DRY DENSITY,Ibs. per cubic ft.
LL LIQUID LIMIT, % Q DEPTH OF ENCOUNTERED GROUNDWATER
PI PIASTIC INDEX DURING IXCAVATION
2 SUBSEQUENT GROUNDWATER LEVEL W/DATE
:�
Earth Consultants Inc. LEGEND
���� Cexnixlink..d I i�jinccrs.Guilogisls d�lvlviranui�ni.d S[u�ntisls
Proj. No.uo69:-3 �Date o�t. zoo4 Piate Al
Test Pit Log
Project Name: Sheet of
Stone Rid e III 1 1
Job No. Logged by: Date: Test Pit No.:
11069-3 SSR 10/8/04 TP-1
Excavation Contador: Ground Surface Elevation:
Aero Construction 450'
Notes:
� o r o � o surtace cond�tbns: Depth of Topsoil &Sod 6": grass
General 1N
a� a « � U �
Notes (%) � N a " � � �
SM Reddish brown sitty SAND with gravel, medium dense, moist
�
2
-brown
3 -dense
-decrease in gravel
>>�8 4 -30.4%fines
5
6 -very dense
�
9.3
8 Test pit terminated at 8.0 feet below existing grade. No groundwater
encountered during excavation.
�
a
�
0
c�
U
W
�
a
c9
g Test Pit Log
�; Earth Consultants Inc. Stone Ridge III
o �`°„�"�Q'�""`S.�°�'°s��°`�'""°""�„`��S King County, Washington
�
a
�
� Proj.No. 11069-3 Dwn. GLS Date Oct. 2004 Chedced SSR Date 10/14/04 Plate A2
Subsurface conditions depicted represent our observations at the 6me and location of this exploratory hole,modified by engineering tests,analysis
and judgment. They are not necessarily represenNdtive of other times and bcations.We cannot accept responsibility for the use or interpretation by
others of information presented on this log.
Test Pit Log
Projed Name: Sheet of
Stone Rid e III 1 1
Job No. Logged by: Date: Test Pit No.:
11069-3 SSR 10/8/04 TP-2
Excavation Contactor: Ground Surface Elevation:
Aero Construction 440'
Notes:
c, o r m � o Surface Conditions: Depth of Topsoil 8� Forest Duff 12"
General W
Notes (�/,) `� �. p �'' � j i.
(9 tn �n v�
SM Red brown silty SAND with gravel, medium dense, moist
�
2
3 -gray brown
4 -dense
6.1
5 -very dense
s
�
6.5
8 Test pit terminated at 8.0 feet below existing grade. No groundwater
encountered during excavation.
�
a
0
c�
U
W
'a
�
m
� Earth Consultants Inc. Test P�t �09 ,
� Stone Ridge III
o �°`�'"'�'a'�"e"s.�"`�,"'°'u"��'�""`�'S King County, Washington
�
a
�
� Proj.No. 11069-3 Dwn. GLS Date Oct. 2004 Chedced SSR Date 10/14/04 Plate A3
Subsurface conditions depicted represent our observations at the time and location of this exploratory hole,modified by engineering tests,analysis
and judgment. They are not necessanly representative of other times and locations.We cannot accept responsibility for the use or interpretation by
others of information presented on this ioq.
Test Pit Log
Project Name: Sheet of
Stone Rid e ill 1 1
Job No. Logged by: Date: Test Pit No.:
11069-3 SSR 10/8/04 TP-3
Excavation Contador: Ground Surface Elevatan:
Aero Construction 448'
Notes:
� — t m � o Surface Conditions: Depth of Topsoil 8 Sod 6": grass
General W L $ a �
Notes (�/,) �� p LL � � �
SM Reddish brown silty SAND with gravel, medium dense, moist
�
2
3 �ray brown
-dense
�0.3 4 -slightly cemented
-28.0%fines
5
6 I
7
10.5
S Test pit terminated at 8.0 feet below existing grade. No groundwater '
encountered during excavation. '
�
a
�
0
t9
U
W
>
a
�
g Test Pit Log
�
Earth Consultants Inc. Stone Ridge III
a ���.���,���
� King County, Washington
a
�
F Proj. No. 11069-3 Dwn. GLS Date Oct. 2004 Checked SSR Date 10/14/04 Plate A4
Subsurface conditions depicted represent our observations at the time and location of this e�loratory hole,modified by engineering tests,analysis
and judgment. They are not necessarily representative of other Gmes and locations.We cannot acoept responsibility for the use or interpretation by
others of information presented on this lop.
APPENDIX B
LABORATORY TEST RESULTS ,
E-11069-3
Earth Consultants, Inc.
Particle Size Distribution Report
�
� � £ �
m � � � � s � x � & � � � � �
�ao
so
�
�o
z 60
�
� �
z
U
� �
a
30
zo
I�
�o
0
200 100 10 1 0.1 0.01 0.001
GRAIN SIZE- mm
%COBBLES 96 GRAVEL %SAND %SILT %CLAY USCS AASHTO PL LL
0 14.8 54.8 30.4 SM
❑ 17.1 54.9 28.0 SM
SIEVE PERCENT FINER SIEVE PERCENT FINER SOIL DESCRIPTION
inches � � number � � O TP-1:4.0'-SM
� � Tan silty Sand;11.8%moisture
1.5 100.0 100.0 #4 852 82.9
3/4 94.4 100.0 #8 79.6 77.1 ❑TP_3:3.5'�M
3B 92.5 90.8 #16 752 71.0 Tan sitry Sand with gravel;to.3%moiswre
#30 69.4 64.8
#50 58.2 54.0
#!100 42.7 39.7
#200 30.4 28.0
GRAIN SIZE REMARKS:
�60 0.328 0.422 O Tech:SEP
�3p 0.0852
p�� ❑Tech:SEP
COEFFICIENTS
C�
C�
o Sou�e: Sample No.:TP-1 Elev./Depth:4.0'
❑Souroe: Sample No.:TP-3 Elev./Depth: 3.5'
EARTH �"�`:
Project: Stone Ridge III
CONSULTANTS, INC. P � No.: E-11069-3 Plate B�
DISTRIBUTION
E-11069-3
6 Copies Novastar Development
18215 — 72"d Avenue South
Kent, Washington 98032
Attention: Mr. Wayne Potter
2 Copies KBS III, LLC
12320 Northeast Eighth Street, Suite 100
Bellevue, Washington 98005
Attention: Mr. Curtis Schuster
�� �
�I �
I
I
I
' 1
� ;
I
i
i
Earth Consultants, Inc.