HomeMy WebLinkAboutSEPA E97-0014 - SPRINT SPECTRUM - BURLINGTON NORTHERN INTERMODAL YARD PCS ANTENNASPRINT SPECTRUM
PCS ANTENNA FACILITY
BNSF BURLINGTON NORTHERN
INTERMODAL YARD
12400 51ST PLACE SO.
E97-0014
• •
CITY OF TUKWILA
DETERMINATION OF NONSIGNIFICANCE (DNS)
DESCRIPTION OF PROPOSAL:
INSTALLATION OF AN 80 FT MONOPOLE, WITH CUP & DR
PROPONENT: SPRINT SPECTRUM
LOCATION OF PROPOSAL, INCLUDING STREET ADDRESS, IF ANY:
ADDRESS: 12400 51 PL 5
PARCEL NO: 017900-1970
SEC/TWN/RNG:
LEAD AGENCY: CITY OF TUKWILA FILE NO: E97-0014
The City has determined that the proposal does not have a probable
significant adverse impact on the environment. An environmental
impact statement (EIS) is not required under RCW 43.21c.030(2)(c).
This decision was made after review of a completed environmental
checklist and other information on file with the lead agency. This
information is available to the public on request.
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This determination is final and signed this (((`v day of JJV4
199.7.
Steve Lancaster, Responsible Official
City of Tukwila. (206) 431-3670
6300 Southcenter Boulevard
Tukwila, WA 98188
Copies of the procedures for SEPA appeals are available with the
Department of Community Development.
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AFFIDAVIT
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Name of Project SPRINT SPRTIAIAA Signature
File Number E9-1- OOI y
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City of Tukwila
John W. Rants, Mayor
Department of Community Development Steve Lancaster, Director
MEMORANDUM
To: Steve Lancaster
From: Michael Jenkins
Date: July 15, 1997
Re: E97-0014, SEPA review on application by Sprint Spectrum for an
80 foot monopole on the Burlington Northern Intermodal yard,
12400 - 51st Place S.
Project Description:
This SEPA review is for a proposal to locate an 80 foot monopole on the
Burlington Northern Intermodal Yard. The proposed development will include the
monopole accompanied by ground cabinets located on an 160 sq. ft. concrete
pad, surrounded by a fenced area measuring approximately 600 square feet.
Backup power will be provided through a compressed gas tank system. A total
of 12 antennae will be affixed to the top of the monopole with up to 4 antennas
mounted on each array. A twelve inch Global Positioning System (GPS)
antennae will be mounted on the center of the pole. The monopole will be used
to transmit wireless telecommunication signals for telephone, fax, pagers and
other similar technologies.
Agencies with jurisdiction:
None
Comments to SEPA checklist:
Pg. 3, section 1: A geotechnical report has been submitted. A land altering permit will
be required. Project must comply with Tukwila's Storm Water Management Ordinance
where development impacts existing drainage system.
Pg. 6, section 4. Photinia and Lelandyii Cedar will be planted, to obtain a mature growth
of 20 feet and 60 feet, respectively, to screen ground equipment and monopole
Pg. 8, section 8. Approval of Design Review and Conditional Use Permit is required for
this project. Project is in Height Exception Area, but is exempt due to nature of
construction.
6300 Southcenter Boulevarc4 Suite #100 • Tukwila, Washington 98188 • (206) 431-3670 • Fax (206) 431-3665
E97-0014
SEPA Checklist - Sprint Spectrum Monopole
12400 - 51st Place S.
July 15, 1997
Summary of Primary Impacts:
• Earth
The entire site is generally flat, however the project area is located between two
paved lots with a 7 foot grade change between them. Approximately 7 feet of fill will
be required to obtain a level surface. A geotechnical report was completed showing
fill soils being sandy silt with gravel. Surface layers are primarily fill due to
construction of adjacent parking Tots. A culvert will be installed under the site to
promote drainage. A concrete wall will be included around project to insure site
stability
• Air
Negligible vehicle emissions will occur during construction. The backup generator
may also produce exhaust emission
• Water
No dredging or filling from surface water or wetlands. A culvert will be installed to
maintain drainage. No discharge of waste materials to surface waters will occur. No
withdraw or discharge of groundwater will occur. Additional water runoff from 160
sq. ft concrete pad will occur, flowing to existing drainage swale. The existing
drainage swale may be replaced with a culvert. All construction in and around
existing drainage field(s) must comply with Tukwila's Storm Water Management
Ordinance
• Plants
Existing brambles and brush will be removed, with Photinia and Leylandii Cedar as
replacement surrounding the site.
• Animals
Small mammals found in the area. No threatened or endangered species known in
area.
• Energy/Natural Resources
Electricity will run electronic equipment. telephone services will be provided, with
battery backup and an gas powered internal backup generator if power failure
occurs.
E97-0014
SEPA Checklist - Sprint Spectrum Monopole
12400 - 51st Place S.
July 15, 1997
• •
• Environmental Health
No significant health impacts have been identified from proposed technology.
Environmental Impacts are exempt from environmental review. Minor traffic and
construction noise will occur during two week period. No other significant noise will
be generated by project. Project will produce Tess noise than existing Intermodal
Modal Yard produces.
• Land/Shoreline Use
Development is located in the Manufacturing Industrial Center - Heavy (MIC/H)
zone. The properties surrounding the proposed development are primarily single
family and are zoned Low Density Residential (LDR), No demolition of structures is
proposed. The project must comply with Tukwila Design Guidelines in the Zoning
Code. The site is located within Seismic Risk Zone 3. The applicant has proposed
an appropriate foundation for the monopole to meet associated seismic
requirements. The proposal must also obtain approval of a Conditional Use Permit
(TMC 18.64). The site is also located in the Building Height Exception area (TMC
18.50.030) but proposed monopole falls with the 6 story limitation, as indicated in
Figure 3 of TMC 18.50.030.
• Housing
No housing is proposed nor will development reduce housing.
• Aesthetics
The proposed monopole for the project is 80 feet high. Views of the monopole and
site from surrounding residential neighborhood are blocked by existing trees on and
off site. The applicant has proposed vegetative screening that will be 20 to 60 feet in
height at maturity. The applicant has also proposed painting of the monopole and
antennae to blend in with its surrounding, when and where possible. The project is
also subject to approval of a Design Review application (TMC 18.60).
• Light and Glare
The monopole will have a red beacon on its apex, as required by the FAA, but will
not produce significant light or glare. No offsite Tight or glare will be produced.
• Recreation
No impact.
• Historic/Cultural Preservation
No known places or landmarks.
E97-0014 • 1
SEPA Checklist - Sprint Spectrum Monopole
12400 - 51st Place S.
July 15, 1997
• Transportation
The access to the development will be off 51st PI. S., through the parking lot for the
Burlington Northern Intermodal Yard. One vehicle trip per month is anticipated for
service and maintenance. No parking spaces will be eliminated.
• Public Services
Proposed development will not impact or require specific public services.
• Utilities
The facility will be served by Puget Sound Energy and US West Communications.
Recommendations:
DNS
CITY OF TUKWILA
NOTICE OF APPLICATION
Sprint Spectrum, by The Walter Group, has filed a SEPA environmental checklist for a
proposed 80 foot Monopole with supporting ground equipment, for the establishment of a
Personal Communication System (PCS) Base Station, to be located at 12400 - 51st
Place S, Tukwila, WA.
Permits applied for include:
• Conditional Use Permit
• Design Review
Other known required permits include:
• Building Permit
• Land Altering Permit
Studies required with the applications include:
• Geotechnical Report
FILES AVAILABLE FOR PUBLIC REVIEW
The project files are available at the City of Tukwila Department of Community
Development (DCD), 6300 Southcenter Boulevard, Suite #100, Tukwila, WA.
Project Files include: Conditional Use Permit; Design Review; SEPA checklist, with
supporting documents
OPPORTUNITY FOR PUBLIC COMMENT
Your written comments on the project are requested. They must be delivered to DCD
at the address above or postmarked no later than 5:00 P.M., July 30, 1997.
APPEALS
You may request a copy of any decision, information on hearings, and your appeal rights
by calling DCD at 431-3670.
For further information on this proposal, contact Michael Jenkins at 431-3685 or visit
our offices at 6300 Southcenter Boulevard, Suite #100, Monday through Friday, 8:30 a.m.
to 5:00 p.m. Our telephone number is 431-3670
Application Filed: June 4, 1997
Notice of Completeness Issued: June 23, 1997
Notice of Application Issued: July 7, 1997
CITY OF TUKWILA
Departmerilf Community Development •
6300 Southcenter Boulevard, Tukwila, WA 98188
Telephone: (206) 431-3670
RECEIVED
CITY OF TUKWILA
JUN 0 4 1997
SEPA APPLICATION CHECKLIST
FOR STAFFUSE: ONL Y
Planner
File Number:
Receipt Number:
Cross-reference files:
oo
Applicant notified of incomplete application:
-Applicant notified of complete. application:
Notice of application issued:
A. NAME OF PROJECT/DEVELOPMENT:
Sprint Spectrum PCS facility at the Burlington Northern Intermodal Yard
B. LOCATION OF PROJECT/DEVELOPMENT: (address and accessors parcel number(s))
12400 51st Place South, Tukwila WA 98178
Tax parcel No.: 176060-0225
Quarter:cwSection: 11 Township: 23 NortRange: 4 East
(This information maybe found on your tax statement)
C. PROJECT DESCRIPTION:
Installation of an 80' monopole with associated ground-based equipment to provide
wireless telephone service (PCS)
D. APPLICANT:
NAME: Martin Garthwaite
ADDRESS:The Walter Group; 120 Lakeside Ave. Ste 310; Seattle WA 98122
PHONE: (206) 328-0808
SIGNATURE:
DATE:
ENVIRONMENTAL CE ECKIST
A. BACKGROUND
1. Name of Proposed Project, if applicable:
Sprint Spectrum PCS facility at the Burlington Northern Intermodal Yard
2. Name of Applicant:
The Walter Group, representing Sprint Spectrum ,c/o Martin Garthwaite
3. Address and phone number of applicant and contact person:
Martin Garthwaite
The Walter Group
120 Lakeside Ave., Suite 310
Seattle, WA 98122
4. Date checklist prepared:
June 3, 1997
5. Agency requesting checklist:
City of Tukwila
6. Proposed timing or schedule (including phasing, if applicable):
Control No.
Epic File No.
Fee $ 325 Receipt No.
RECEIVED
CITY OF.TUKWIL.A
JUN 0 41997
PERMIT CENTER
Applicant will begin construction as soon as necessary permits and approvals are obtained and will
continue for approximatley two weeks.
7. Do you have any plans for future additions, expansion or further activity related to or
connected with this proposal? If yes, explain.
No expansion is anticipated.
8. List any environmental information you know about that has been prepared, or will be
prepared, directly related to this proposal.
None known.
9. Do you know whether applications are pending for governmental approvals of other
proposals directly affecting the property covered by your proposal? If yes, explain.
None known.
10. List any government approvals or permits that will be needed for your proposal, if known.
City of Tukwila: CUP, Design Review; SEPA, Building Permit
• •
FAA: "To C Determination" regarding lighting visa vi Boeing Field
FCC: Radio Station Authorization for Commercial Mobile Radio Services, Personal Communication Services,
Broadband (license granted June 23, 1995).
11. Give a brief, complete description of your proposal, including the proposed uses and the size of the
project and site. There are several questions later in this checklist that ask you to describe certain
aspects of your proposal. You do notneed to repeat those answers on this page. Section E requires
a complete description of the objective and alternatives of your proposal and should not be
summarized here.
Sprint Spectrum proposes to construct a PCS facility on the Burlington Northern Intermodal Yard located
at 12400 51st Place South, Tukwila, Washington. The proposed facility consists of an 80 foot tall
monopole supporting a triangular antenna mounting platform. Please refer to the attached drawings.
Each 12' side of the antenna platform supports up to four antennas. Each antenna measures
approximately five feet tall, four inches wide, and two inches deep.
A 20' by 30' fenced area at the base of the monopole will contain the site's signal processing equipment
in five self-contained metal cabinets measuring approximately 30" by 30" by 5'6" tall. There will also be
a tank of compressed gas to provide back-up power in the event of a power outage which lasts longer than
two hours.
The north-west and south-west sides of the facility (those sides visible from the residential areas of
Allentown) will be landscaped with 20' Photina (an evergreen shrub) and 50' to 60' Leylandyii Cedar
trees.
12. Location of the proposal. Give sufficient information for a person to understandthe precise location
of your proposed project, including a street address, if any.If a proposal would occur over a range
of area, provide the range or boundaries of the site(s) Provide a legal description, site plan, vicinity
map, and topographic map, if available. While you should submit any plans required by the
agency, you are not required to duplicate maps or detailed plans submitted with any permit
applications related to this checklist.
Address: 12400 51st Place South, Tukwila, WA 98178, commonly known as the
Burlington Northern Intermodal Yard
Legal description: Please see attached legal description.
Site plan, vicinity map: Please see attached site plans and vicinity map.
13. Assessor Parcel Number:
King County Assessor's Parcel Number: 176060-0225.
B. ENVIRONMENTAL ELEMENTS
1. EARTH
a. General description of the site (circle one): Flat, rolling, hilly, steep
slopes,mountainous, other:
b. What is the steepest slope on the site
(approximate percent slope)?
The site sits in a narrow strip between two large flat parking lots; the southern
parking lot is approximately 7' higher than the northern parking lot.
Consequently, while the area is generally characterized as being flat, the site
itself will sit on a grade which attains as much as a 2H: 1V
• •
(Horizontal:Vertical) ratio. Approximately 7 feet of structural fill will be
required to obtain a level surface.
c. What general types of soils are found on the site (for example, clay,
sand, gravel, peat, muck)? If you know the classification of agricultural
soils, specify them and note any prime farmland.
Upper seven feet are fill soils generally composed of stiff to very stiff, moist,
brown , sandy silt with gravel. This was underlain to a depth of 15.5 feet by
fill soils generally consisting of loose to medium dense, moist, brown , silty
sand with gravel. This, in turn, was underlain with meduim dense, dark gray,
sand with variable amounts of silt. Soil below 18 feet was observed to be
saturated. (Source: Proprietary geotechnical engineering evaluation, May,
1997).
d. Are there surface indications or history of unstable soils in the immediate
vicinity?
The surface layers appear to be fill, probably relating to the construction of the
adjacent parking lots
e. Describe the purpose, type and approximate quantities of any filling or
grading proposed. Indicate source of fill.
Approximately 7 square feet of structural fill will be required to make a level
surface for the signal processing equipment. A drainage swale-runs through
the area in question, so in addition, a culvert will be installed beneath the site
to allow continued drainage.
f. Could erosion occur as a result of clearing, construction, or use? If so,
generally describe.
g.
Generally speaking, no, because the site is small and appears to be stable.
Nonetheless, the slope beneath the site will be bench cut, fill soil will be
properly compacted, and a segmantal conrete masonry wall, approximately 2
feet heigh, will be located at the base of the fill wall to insure that the site is
stable.
About what percent of the site will be covered with impervious surfaces
after project construction (for example, asphalt or buildings)?
The site will have a cement equipment pad which is approximately 8' by 12' by
a few inches thick. This change in impervious surface is nominal.
h. Proposed measures to reduce or control erosion, or other impacts to the
earth, if any:
The existing slope will be bench cut, fill will be properly compacted, and a
small segmantal conrete masonry wall, approximately 2 feet heigh, will be
located at the base of the fill wall.
2. AIR
a. What types of emissions to the air would result from the proposal (i.e.,
dust,automobile, odors, industrial wood smoke) during construction and
• •
when the project is completed? If any, generally describe and give
approximate quantities if known.
During construction, there will be negligible vehicle exhaust emissions. After
completion, the site's back-up generator will occassionally produce a negligble
amount of exhaust emmissions.
b. Are there any off-site sources of emissions or odor that may affect your
roposal? If so, generally describe.
No.
c. Proposed measures to reduce or control emissions or other impacts to
ir, if any.
None necessary.
3. WATER
a. Surface
1) Is there any surface water body on or in the immediate vicinity of
the site (including year-round and seasonal streams, lakes,
ponds, wetlands) If yes, describe type and provide names. If
appropriate, state what stream or river it flows into.
No.
2) Will the project require any work in or adjacent to (within 200
feet) of the described waters? If yes, please describe and attach
available plans.
No.
3) Estimate the amount of fill and dredge material that would be
placed in or removed from surface water or wetlands and indicate
the area of the site that would be affected. Indicate the source of
fill material.
The proposal requires no filling or dredging of material placed in or
removed from surface water or wetlands.
4) Will the proposal require surface water withdrawals or
diversions? Give general description, purpose, and approximate
quantities, if known.
No. A drainage swale runs through the project area; however, a
culvert will be installed to maintain this drainage.
5) Does the proposal lie within a 100 -year flood plain? If so, note
location on the site plan.
No.
• •
6) Does the proposal involve any discharges of waste materials to
surface waters? If so, describe the type of waste and anticipated
volume of discharge.
No. The proposal does not involve any discharges of waste materials
to surface waters.
b. Ground:
1) Will ground water be withdrawn, or will water be discharged to
ground water? Give general description, purpose, and
approximate quantities, if known.
No ground water will be withdrawn and no water will be discharged
to ground water.
2) Describe waste material that will be discharged into the ground
from septic tanks or other sources, if any. For example: Domestic
sewage, industrial, containing the following chemicals agricultural;
etc. Describe the general size of the system, the number of such
systems, the number of houses to be served if applicable, or the
number of animals or humans the system(s) are expected to serve.
None. No waste material will be discharged into the ground from
septic tanks or other sources. The proposed radio communications
facility is unmanned. No water or domestic sewage service is required.
c. Water Runoff (including storm water):
1) Describe the source of runoff (including storm water) and method
of collection and disposal, if any (include quantities, if known).
Where will this water flow? Will this water flow into other
waters? If so, describe.
The proposed facility will generate negligible additional water runoff
from natural precipitation. The additional water runoff will result from
the proposed ground equipment's concrete pad. The negligible water
runoff will flow into the existing drainage swale beneath and adjacent
to the site. The runoff will not flow into surface water.
2) Could waste materials enter ground or surface waters?
Not applicable, as the proposed facility will not generate waste
materials.
d. Proposed measures to reduce or control surface, ground, and runoff water
impacts, if any.
The drainage swale beneath the site will be replaced by a culvert.
4. PLANTS
a. Check or circle types of vegetation found on the site:
deciduous tree: alder, maple, aspen, other
• •
evergreen tree: fir, cedar, pine, other
X shrubs
X grass
pasture
crop or grain
wet soil plants: cattail, buttercup, bulrush, skunk cabbage, other
water plants: water lily, eelgrass, milfoil, other
X_other types of vegetation: brambles, misc. scrub
b. What kind and amount of vegetation will be removed or altered?
The brambles and small bushes in the project area will be removed.
c.. List threatened or endangered species known to be on or near the site.
None known.
d. Describe proposed landscaping, use of native plants, or other measures to
preserve or enhance vegetation on the site, if any:
Photina, growing to a mature height of 20 feet, and Leylandyii Cedar, growing
to a mature height of 50 to 60 feet, will be planted on the north-west and south-
west sides of the project area.
5. ANIMALS
a. Underline any birds and animals which have been observed on or near the
or are known to be on or near the site:
birds: hawk, heron, eagle, songbirds, other: Crows
mammals: deer, bear, elk, beaver, other: Squirrels
fish: bass, salmon, trout, herring, shellfish, other: None
b. List any threatened or endangered species known to be on or near the
site.
None known.
c. Is the site part of a migration route? If so, explain.
Not known.
d. Proposed measures to preserve or enhance wildlife, if any:
Not applicable.
6. ENERGY AND NATURAL RESOURCES
a. What kinds of energy (electric, natural gas, oil, wood stove, solar) will be
used to meet the completed project's energy needs?
• •
Sprint Spectrum will use electricity to run electronic radio equipment.
Telephone service will also be required. The equipment has two hours of
internal battery back-up but for outages which last longer than two hours a
back-up generator, running on LP gas, will provide power.
b. Would your project affect the potential use of solar energy by adjacent
properties? If so, generally describe.
No. The proposed facility will not shade adjacent properties.
c. What kinds of energy conservation features are included in the plans of
this proposal? List other proposed measures to reduce or control energy
impacts, if any.
None are necessary, as energy impacts are negligible.
7. ENVIRONMENTAL HEALTH
a. Are there any environmental health hazards, including exposure to toxic
chemicals, risk of fire and explosion, spill, or hazardous waste, that could
occur as a result of this proposal? If so, describe.
No. No significant environmental health hazards have been identified from
similar cellular sites. The project is categorically exempt from Environmental
Assessmment under NEPA by the FCC in FCC ET Docket No. 93-62,
paragraphs 75 - 93. The FCC preempts local regulation of the environmental
effects of radio-frequency energy to the extent that the project complies with
Federal law. ET Docket No. 93-62, paragraphs 164 - 168.
1) Describe special emergency services that might be required.
The proposal would not require any special emergency services.
2) Proposed measures to reduce or control environmental health hazards, if
any:
None are necessary as there are no environmental health hazards associated
with this project.
b. Noise
1) What types of noise exist in the area which may affect your project, (for
example: traffic, equipment, operation, other)?
None. No noise exists in the area which would affect the proposal.
2) What types of levels would be created by or associated with the project on
a short-term or a long -t erm basis (i.e., traffic, construction, operation,
other)? Indicate what hours noise would come from the site.
There will be some traffic noise associated with the installation and placement
of the antennas and equipment cabinets. Such noise would only occur during
the two week construction period. Thereafter, the only source of noise would
be the extremely rare operation of the site's back-up power generator during
power outages lasting longer than two hours.
3) Proposed measures to reduce or control noise impacts, if any:
The site sits on an industrial lot which is used for transfering containers from
trains to trucks. The extremely intermittent operation of the facility's generator
will produce less noise than is produced on a continual basis by the site's existing
users. It is also far enough from adjacent properties that noise levels will, in any
event, be negligible.
8. LAND AND SHORELINE USE
a. What is the current use of the site and adjacent properties?
Use of site
The site is currently used as an intermodal yard (a yard used to transfer
containers from railcars to trucks).
Adjacent Properties
North: intermodal yard
South: intermodal yard
East: intermodal yard
West: cellular antenna facility
b. Has the site been used for agriculture? If so, describe.
No.
c. Describe any structures on the site.
There are a number of large warehouse -type structures on the site which are
associated with the operation of the intermodal yard.
d. Will any structures be demolished? If so, what?
No structures will be demolished.
e. What is the current zoning classification of the site?
The current zoning classification of the site is heavy industrial.
f. What is the current comprehensive plan designation of the site?
The current comprehensive plan designation is industrial.
g.
If applicable, what is the current shoreline master program designation of
the site?
Not applicable.
h. Has any part of the site been classified as an "environmentally sensitive"
area? If so, specify.
The project's geotechnical report states that the site lies within Seismic Risk
Zone 3 and an appropriate pier foundation for the monopole has been designed.
• •
I. Approximately how many people would reside or work in the completed
project?
None. The site is unmanned One employee will provide maintenance services
once per month.
j. Approximately how many people would the completed project displace?
None.
k. Proposed measures to avoid or reduce displacement impacts, if any.
There are no displacement impacts associated with this project.
1. Proposed measures to ensure the proposal is compatible with existing and
projected land use and plans, if any.
The project proposal is compatible with existing and projected land uses and
plans. The site is currently zoned heavy industrial. The site is also at least 250'
from the closest residentially zoned property. Vegetative screening, growing
to a height of 50 to 60 feet, will screen the facility from the residential
properties.
9. HOUSING
a. Approximately how many units would be provided, if any? Indicate
whether high, middle, or low-income housing.
None.
b. Approximately how many units, if any, would be eliminated? Indicate
whether high, middle, or low-income housing.
None.
c. Proposed measures to reduce or control housing impacts, if any.
None are anticipated to be necessary.
10. AESTHETICS
a. What is the tallest height of any proposed structure(s), not including
antennas; what is the principal exterior building material(s) proposed?
The proposed monopole is 80 feet high. The principal exterior building
material is steel.
b. What views in the immediate vicinity would be altered or obstructed?
The views of the facility from the neighboring residential properties are already
extremely intermittent due to a substanial number of trees both on and off site.
The monopole and the attendant vegetative screening will slightly alter views
from these properties.
c. Proposed measures to reduce or control aesthetic impacts, if any.
• •
Evergreen vegetative screening, growing to a mature height of 50 to 60 feet,
will screen all but the top 20 to 30 feet of the facility from neighboring
residential properties.
11. LIGHT AND GLARE
a. What type of light or glare will the proposal produce? What time of day
would it mainly occur?
Apart from a small red beacon light which the FAA may require, the proposal
would produce no light or glare.
b. Could light or glare from the finished project be a safety hazard or
interfere with views?
No.
c. What existing off-site sources of light or glare may affect your proposal?
No existing off-site sources of light or glare would affect the proposal.
d. Proposed measures to reduce or control light and glare impacts, if any.
None are anticipated to be necessary.
12. RECREATION
a. What designated and informal recreational opportunities are in the
immediate vicinity?
None.
b. Would the proposed project displace any existing recreational uses? If so,
describe.
No.
c. Proposed measures to reduce or control impacts on recreation, including
recreation opportunities to be provided by the project or applicant, if any:
None are anticipated to be necessary.
13. HISTORIC AND CULTURAL PRESERVATION
a. Are there any places or objects listed on, or proposed for, national, state,
or local preservation registers known to be on or next to the site?
None known.
b. Generally describe any landmarks or evidence of historic, archaeological,
scientific, or cultural importance known to be on or next to the site.
None known.
• •
c. Proposed measures to reduce or control impacts, if any.
None.
14. TRANSPORTATION
a. Identify public streets and highways serving the site, and describe
proposed access to the existing street system. Show on site plans, if any.
The site is served by 51st Place South. Please see the plans which
accompanied this application.
b. Is site currently served by public transit? If not, what is the approximate
distance to the nearest transit stop?
Public transit is not applicable to this proposal.
c. How many parking spaces would the completed project have? How many
would the project eliminate?
Routine maintenance visits will utilize existing site parking without adverse
impacts. No parking spaces will be eliminated.
d. Will the proposal require any new roads or streets, or improvements to
existing roads or streets, not including driveways? If so, generally describe
(indicate whether public or private).
No new streets/roads will be required. Access to the site is from existing ROW's.
e. Will the project use (or occur in the immediate vicinity of) water, rail, or
air transportation? If so, generally describe.
It will be close to rail transportation but will have no impact thereon.
f. How many vehicular trips per day would be generated by the completed
project? If known, indicate when peak volumes would occur.
One vehicle trip per month will be made for routine maintenance.
g. Proposed measures to reduce or control transportation impacts, if any:
None are anticipated to be necessary.
15. PUBLIC SERVICES
a. Would the project result in an increased need for public services (i.e., fire
protection, police protection, health care, schools, other)?
If so, generally describe.
No. The project consists of an antenna support structure, transmitting and
receiving antennas and self-contained equipment cabinets. The facility is
inaccessible to the general public. The cabinets contain alarms and 24 hour
monitoring equipment for additional security.
• •
b. Proposed measures to reduce or control direct impacts on public services,
if any.
None.
16. UTILITIES
a. Underline utilities currently available at the site: electricity, natural gas,
water, refuse service, telephone, sanitary sewer, septic system, other.
b. Describe the utilities that are proposed for the project, the utility
providing the service, and the general construction activities on the site or
in the immediate vicinity which might be needed.
Electricity: Puget Sound Power and Light
Telephone: US West Communications.
C. SIGNATURE
The above answers are true and complete to the best of my knowledge. I
understand that the lead agency is relying on them to make its decision.
Signature of Proponent
Date Submitted: L.11/1 3
•
•
PACIFIC TESTIN LABORATORIES
Since 1926
Seattle • Bothell • Tacoma • Peninsula • Portland • One Lab • One Consultant • One Solution
SPRINT SPECTRUM, L.P.
Geotechnical Engineering Evaluation
SETA -008-07
Tukwila, Washington
Project No. 9704-4120
May, 1997
RECEIVED
CITY OF TUKWILA
JUN 0 41997
PERMIT CENTER
PACIFIC TESTING LABORATORIES
Since 1926
Seattle • Bothell • Tacoma • Peninsula • Portland • One Lab • One Consultant • One Solution
May 28, 1997
Project No. 9704-4120
Mr. Chris Cecil
THE WALTER GROUP, INC.
120 Lakeside Avenue, Suite 310
Seattle, Washington 98122
Subject: Geotechnical Engineering Evaluation
Sprint Spectrum Site No. SETA -008-07
BNSF Intermodal Yard PCS Site
12400 51' Place South
Tukwila, Washington
Dear Mr. Cecil:
Pursuant to your request, Professional Services Industries, formerly Pacific Testing Laboratories
(PTL/PSI), is pleased to submit this report describing our recent geotechnical engineering evaluation for the
above -referenced site. The purpose of this study was to interpret general surface and subsurface site
conditions, from which we could evaluate the feasibility of the project and formulate design
recommendations concerning site preparation, equipment pad and tower foundations, structural fill, and
other considerations. Our scope of services consisted' of a surface reconnaissance, a subsurface
exploration, geotechnical analyses, and report preparation. We received written authorization for our
service from Sprint Spectrum, L.P. through our proposal dated April 24, 1997. This report has been
prepared for the exclusive use of Sprint Spectrum L.P., and their agents in care of The Walter Group, for
specific application to this project in accordance with generally accepted geotechnical engineering practice.
We are also in the process of preparing an Environmental Transaction Screen for this parcel. That report
will be submitted under separate cover.
PSI (formerly Pacific Testing Laboratories)
11824 N. Creek Parkway N., Suite 101, Bothell, Washington 98011 Tel (208) 4854244 Fax (208) 485-4811
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Page 2
This report is provided for the information of the client only. Reproduction and transmittal of this report,
or any section of this report, to a third party, by any means, except in full, without the written permission
of PTL/PSI is prohibited.
Thank you for using PTL/PSI. If you have any questions, or if we can be of further assistance to you,
please contact us at (425) 485-4244.
Sincerely,
G. Aaron McMichael, P.E.
Senior Geotechnical Engineer
AM/kh
Attachments: Figure 1 Vicinity Map
Figure 2 Site and Exploration Plan
Appendix A Boring Log
•
PACIFIC TESTING LABORATORIES
Since 1926
Seattle • Bothell • Tacoma • Peninsula • Portland • One Lab • One Consultant • One Solution
SPRINT SPECTRUM, L.P.
Geotechnical Engineering
Evaluation
BNSF Intermodal Yard PCS Site
(SETA -008-07)
Tukwila, Washington
Certificate No. 9704-4120
May 1997
• PSI (formerly P•Pic Testing Laboratories)
Engneen • Consultants • Scientists
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Project No.: 9704-4120
May 28, 1997
Page 1
PROJECT DESCRIPTION
The project site is located at 12400 51' Place South, near the intersection of 51' Place South and South
124th Street in Tukwila, Washington (Figure 1). It is our understanding that current development plans call
for construction of an 80 foot tall monopole cellular communications tower and associated concrete
equipment platform. Due to sloping site conditions, the site will be filled with approximately 7 feet of
structural fill to create a level equipment pad. The outer edge of the fill will be sloped at a permanent
inclination of 21-1: 1V (Horizontal:Vertical), and will extend downward to the north to within a few feet of
the adjacent parking area. A small segmental concrete masonry wall, approximately two feet in height, will
be located at the base of the fill slope. The fill area will cross an existing drainage swale which will require
placement of a culvert to allow continued drainage.
The host parcel is occupied by the Burlington Northern Santa Fe Railroad (BNSF) Intermodal Yard - Puget
Sound Hub Center. The attached Site and Exploration Plan (Figure 2) shows the general location of the
proposed tower in relation to other major site features.
It should be emphasized that the conclusions- and recommendations contained in this report are based on
our understanding of the currently proposed utilization of the project site, as derived from written
information and a layout plan supplied to us by The Walter Group. Consequently, if any changes are made
to the project, we recommend that we review the changes and modify our recommendations, if appropriate,
to reflect those changes.
EXPLORATORY METHODS
We explored surface and subsurface conditions at the. project site on May 2, 1997. Our surface
exploration.consisted of a visual reconnaissance. Our subsurface exploration consisted of advancing one
soil boring to a depth of approximately 31.5 feet below the existing site grade. The location of the boring,
designated as B-1, is shown on the attached Site and Exploration Plan (Figure 2).
The location and depth of the exploration performed was selected in relation to the proposed site features,
under the constraints of budget and site access. The location of the boring shown on Figure 2 was obtained
by hand -taping and pacing from existing site features and scaling those measurements onto a layout map.
As such, the exploration location shown on Figure 2 should be considered accurate to the degree implied by
the measuring methods used.
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Boring Methods
Boring B-1 was advanced on May 2, 1997 using a truck mounted hollow -stem auger drill rig. The drill rig
was operated by an independent company working under subcontract to our firm. An experienced geologist
from our firm continuously observed the boring, logged the subsurface conditions, obtained representative
soil samples, and transported the samples to our laboratory for further visual classification. After the
boring was completed, the borehole was backfilled with a mixture of soil cuttings and bentonite chips.
During drilling, soil samples were obtained on 2 1/2 to 5 foot depth intervals using the Standard Penetration
Test (SPT) procedure (ASTM:D 1586). This test and sampling method consists of driving a standard 2 -
inch outside diameter (OD) steel split -barrel sampler a distance of 18 inches into the soil with a 140 -pound
hammer, free -falling a distance of 30 inches. The number of blows required to drive the sampler through
each of the three, 6 -inch intervals is noted, and the total number of blows struck during the final 12 inches
of penetration is considered the Standard Penetration Resistance, or "blow count". If a total of 50 blows is
struck within one 6 -inch interval, the driving is ceased and the blow count is recorded as 50 blows for the
actual number of inches of penetration. The resulting Standard Penetration Resistance values provide a
measure of the relative density of granular soils or the relative consistency of cohesive soils.
The boring log included in Appendix A describes the various types of soils encountered in the boring, based
primarily on interpretations made in the field and supported by any subsequent laboratory testing of the
samples which may have occurred. The log also indicates the approximate depth of the contacts between
different soil types, although these contacts may be gradational or undulating. Where a change in soil type
occurred between sampling intervals, we inferred the depth of contact. In addition, the log indicates the
depth of any groundwater observed in the boring, the Standard Penetration Resistance at each sample
location, and any laboratory tests performed on the soil samples.
SITE CONDITIONS
The following sections describe our observations, measurements, and interpretations concerning surface,
soil, groundwater, and seismic conditions at the project site.
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Surface Conditions
The host parcel consists of a large irregularly shaped parcel utilized as an intermodal transportation yard
by Burlington Northern Santa Fe Railroad. The proposed tower lease site is located on a narrow strip of
northward sloping, naturally vegetated undeveloped land, approximately 40 feet wide. Based on site
topographic information contained on a site plan developed by the project architect, Fraley Stricker
Architects, this slope is inclined at approximately 2H: 1V. The total relief acrbss the proposed tower lease
site and adjacent slope is approximately 7 feet. The proposed tower lease site is bounded on the north and
south by relatively flat -lying asphalt paved areas used primarily for truck and trailer parking and shipping
container storage. The undeveloped strip of land narrows toward the east and eventually pinches out at the
junction of the upper and lower asphalt paved areas. Land bounding the proposed tower lease site to the
west is naturally vegetated and undeveloped, and slopes downward toward the west.
According to the Sprint -Spectrum Candidate Selection Form, the elevation of the proposed tower lease site
is approximately 25 feet above mean sea level.
Subsurface Conditions
On May 2 1997, one exploratory boring was drilled near the tower lease site. Boring B-1 was drilled to a
depth of about 31.5 feet, approximately where shown on Figure 2. Material encountered in the upper 7
feet of the boring consisted of fill soils generally composed of stiff to very stiff moist, brown, sandy silt
with gravel. This material was underlain to a depth of approximately 15.5 feet by fill soils, generally
consisting of loose to medium dense, moist, brown, silty sand with gravel. Soils encountered below a depth
of 15.5 feet generally consisted of loose to medium dense, dark gray, sand with variable amounts of silt.
However, a layer of fine sandy silt, approximately two feet thick, was encountered at a depth of
approximately 18 to 20 feet. Soils encountered below a depth of approximately 18 feet were observed to
be saturated. Upon removal of the auger, the groundwater level in the open boring was observed to be at a
depth of approximately 11 feet.
Seismic Conditions
According to the Seismic Zone Map of the United States contained in the 1994 Uniform Building Code, the
project site lies within Seismic Risk Zone 3. Based on our analysis of the on-site exploration, we interpret
the subsurface site conditions to correspond to a seismic soil profile type S-3, as defined by Table 16-J of
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the 1994 Uniform Building Code. Soil Profile type S-3 applies to a profile consisting of predominantly
more than 20 feet of soft to medium -stiff clay but not more than 40 feet of soft clay.
CONCLUSIONS AND RECOMMENDATIONS
Current development plans call for construction of a new 80 foot tall monopole communications tower and
associated equipment pad. Due to the presence of loose, saturated granular soils, the site is susceptible to
liquefaction. Foundations built above liquefiable soils risk damage from loss of soil bearing support and
large differential settlements during strong seismic events. Therefore, we recommend that the proposed
tower be supported on a drilled pier foundation embedded below the zone of potential liquefiable soils.
Based on the subsurface conditions encountered in our boring, it is our opinion that proposed tower's
drilled pier foundation should penetrate the loose fill and native soils which extend to depths of about 25
feet.
We estimate that the structural fill which will be placed on the existing slope to create a level equipment
pad will induce settlement in the range of several inches within the underlying loose soils. Therefore, the
project schedule should allow several weeks following the placement of the slope fill to permit this
settlement to occur prior to construction. The existing sloping pad site appeared to be stable in its present
condition, and we do not anticipate that placement of the fill soil will cause instability within the existing
slope soils, if the slope is adequately benched and the fill soil properly compacted. However, a slope
stability analysis was not completed for this project. Such an analysis does not appear necessary and was
beyond the scope of our present services. As mentioned previously, the fill slope will be inclined at a final
grade of 2H:1V. We recommend that this slope gradient not be exceeded on all site slopes (north and
west) to enhance long term stability of these slopes. Additionally, the slopes should be protected from
erosion and vegetated as soon possible.
Design criteria for compressive, uplift and lateral support of the drilled pier foundation is presented below.
Our specific recommendations concerning site preparation, equipment pad foundations, tower foundations,
and structural fill are presented in the following sections.
Site Preparation
Site preparation will involve clearing and grubbing, grading, and preparing subgrades. The following
comments and recommendations apply to this site preparation.
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Clearing and Grubbing: Site preparation should include clearing, grubbing, and removal of all surficial
vegetation and root masses, as well as, organic topsoil from foundation and fill areas. Materials stripped
should be wasted off-site. We anticipate that a stripping depth of approximately 12 inches will be required.
However, areas of deeper organic -rich surficial deposits, such as root balls or stumps, should be expected.
Grading: Structural fill required to build the proposed level tower site on the existing slope should be
placed and compacted according to the recommendations presented in the Structural Fill section of this
report. Prior to placing structural fill, the grubbed slope surface should be "bench cut" in a stair -step
fashion forming a series of terraces wide enough to provide access to compaction equipment. The benches
should be a minimum of 4 feet in width. The base of the fill slope should also be provided with a 3 foot
deep by 4 foot wide "keyway" trench. The benches and keyway are necessary to provide a level surface
upon which to support and interlock the structural fill with the existing slope soils, enhancing the stability
of the fill mass. If seepage is encountered within the bench excavations, the seepage area should be
provided with a gravel interceptor drain to prevent destabilizing the structural fill. If seepage is
encountered within the slope excavations, PTL/PSI will be available to provide drainage recommendations
based on specific site conditions.
Wet Conditions: Because of the high silt content of the existing on-site fill soils, these soils are moisture -
sensitive and are prone to disturbance when wet. In the event that "soft" areas in the subgrade are noted,
the contractor should minimize traffic above the prepared subgrade areas to minimize disturbance and
softening which would require removal of the unstable soils. During wet conditions, the use of a working
surface of quarry spalls or clean sand and gravel may be required to protect the subgrade, especially from
vehicular traffic.
Frozen Subgrades: If earthwork takes place during freezing conditions, we recommend that all exposed
subgrades be allowed to thaw and be recompacted prior to placing subsequent lifts of structural fill.
Equipment Pad Foundation
The proposed equipment pad will consist of a poured in place concrete slab -on -grade with thickened edges.
We anticipate that the pad will be relatively lightly loaded. However, we recommend that the thickened
slab edges be designed as spread footings. The following recommendations and comments are provided for
purposes of footing design and construction.
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Subgrade Conditions: The proposed equipment pad and thickened edges may be supported above the
structural fill soils which will be placed to level the site. The placement of the structural fill should result
in a firm and unyielding subgrade. It appears that the north end of the equipment pad will be located at the
crest of the 2H:1 V structural fill slope. Therefore, we recommend that this side of the pad footing extend a
minimum of 2.5 feet below grade to prevent inducing footing load stresses on the slope face soils, and to
prevent the slab from being undermined should the adjacent slope soils slough down slope.
Footings should never be cast atop soft, loose, organic, or frozen soils; nor atop subgrades covered by
standing water. A PTL/PSI representative should be retained to observe the condition of footing subgrades
before concrete is poured to verify that they have been adequately prepared.
Footing Dimensions: We recommend that the thickened edge of the slab be designed as a spread footing
and be constructed to have a minimum width of 12 inches. The near surface site soils consist of sandy silt
with gravel. These soils are frost susceptible. For frost protection, the footings should penetrate at Least 18
inches below the adjacent exterior grades.
Bearing Pressures: A maximum allowable soil bearing pressure of 1,500 pounds per -square -foot can be
used for static footing loads. This bearing pressure can be increased by one-third to accommodate transient
wind or seismic loads. An allowable base friction value of 0.35 and an allowable passive earth pressure of
300 pounds per cubic foot (pcf), expressed as an equivalent fluid unit weight, may be used for that portion
of the foundation embedded more than 1 foot below finished exterior subgrade elevation. However, no
passive earth pressure should be utilized along the north side of the pad foundation adjacent to the slope.
Settlements: We estimate that total post -construction settlements of properly designed footings bearing on
properly prepared subgrades could approach 1 inch, with differential settlements approaching one-half of
the total. However, liquefaction induced differential settlements in the range of 2-3 inches are possible
resulting from strong seismic activity.
Tower Drilled Pier Foundations
We recommend that the proposed tower be supported on a drilled pier foundation. The following
recommendations and comments are provided for the purposes of drilled pier design and construction.
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Compressive Capacities: Due to the presence of loose, liquefaction prone fill and native site soils, we
recommend that the drilled pier penetrate at least 30 feet below the ground surface. For vertical
compressive soil bearing capacity, we recommend using the unit end bearing capacity presented in Table 1
below.
The embedment depth shown in Table 1 refers to the depth of penetration below the proposed level tower
pad site, and assumes that this ground surface elevation will be similar to the level of the existing ground
surface located immediately adjacent to the south. The allowable end bearing capacity, presented in Table
1, includes a safety factor of 1.5 or more. We anticipate that adequate pier embedment for end bearing,
uplift and lateral resistance can generally be obtained within the limits of our exploration.
Frictional Capacities: Due to the potential for liquefaction of site soils extending to an approximate depth
of 25 feet, post liquefaction consolidation could produce significant downdrag forces on the pier
foundation. Therefore, negative skin friction should be assumed to a depth 25 feet and can be calculated
using the value presented in Table 2. A factor of safety has not been applied to increase this negative skin
friction value. Below a depth of 25 feet, frictional resistance of the drilled pier, acting both downward and
in uplift, we recommend using the allowable skin friction value also listed in Table 2. The allowable skin
friction value presented includes a safety factor of 2.0.
Table 2
Allowable Skin Friction Capacities
Depth(feet)
Slag Fnctron (ts
0-25
25-31.5
Downdrag (Negative Value) 0.28
Allowable 0.21
Table 1
Allowable End Bearing Capacities
Depth (feet)
Mlowabfe Bearing Capacity (tsl)
Limiting Point: Resistance.(tsf).
30
1.33 DB
20 TSF
Notes:
D = the embedment depth (in feet) into the bearing layer.
B = pier diameter (feet).
Frictional Capacities: Due to the potential for liquefaction of site soils extending to an approximate depth
of 25 feet, post liquefaction consolidation could produce significant downdrag forces on the pier
foundation. Therefore, negative skin friction should be assumed to a depth 25 feet and can be calculated
using the value presented in Table 2. A factor of safety has not been applied to increase this negative skin
friction value. Below a depth of 25 feet, frictional resistance of the drilled pier, acting both downward and
in uplift, we recommend using the allowable skin friction value also listed in Table 2. The allowable skin
friction value presented includes a safety factor of 2.0.
Table 2
Allowable Skin Friction Capacities
Depth(feet)
Slag Fnctron (ts
0-25
25-31.5
Downdrag (Negative Value) 0.28
Allowable 0.21
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Lateral Capacities: For design against lateral force on the drilled pier, two methods are typically used.
The parameter used to select the appropriate design method is the length to pier stiffness factor ratio DT,
where L is the pier length in inches, and T is the relative stiffness factor. The relative stiffness factor (T)
should be computed by:
0.2
T= —
nh
where E = modulus of elasticity (psi)
I = moment of inertia (in4)
nh = constant of horizontal subgrade reaction (pci)
The factors E and I are govemed by the internal material strength characteristics of the pier.
Representative values of nh for the different soil types at this site are presented subsequently. Piers with a
L/T ratio of less than 2 may be assumed to be relatively rigid and acting as a pole.
The passive pressure approach may be used for this condition. For piers with a La ratio greater than 2,
the modulus of subgrade reaction method is typically used. Both of these methods are discussed below.
Passive Pressure Method: As mentioned earlier, site soils may potentially liquefy to a depth of 25 feet
below the existing ground surface. During the liquefaction process, short term build up of pore water
pressures cause effective stresses to decrease to zero. Therefore, we do not recommend using the passive
pressure approach above a depth of 25 feet.
Below a depth of 25 feet the passive earth pressure approach could be utilized, however, this approach is
conservative by neglecting the redistribution of vertical stress and shear forces that develop near the bottom
of the pier and contribute to resisting lateral loads. We recommend using the allowable passive earth
pressure (expressed as equivalent fluid unit weight) listed in Table 3.
Table 3
Allowable Passive Pressures
Depth.(feet)
Allowable Passive :Pressure (pci)
0-25
25-31.5
0
150
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The allowable passive earth pressure presented in Table 3 may be assumed to be acting over an area
measuring 2 pier diameters in width by 8 pier diameters in depth, neglecting the uppermost 25 feet of
embedment below the ground surface. According to the NAVFAC Design Manual 7.2, a lateral deflection
equal to about 0.01 times the pier length would be required to mobilize the allowable passive pressure
presented above. Higher deflections would mobilize higher passive pressures. When developing the
passive pressure listed in Table 3, we have incorporated -a safety factor of at least 1.5, which is commonly
applied to transient or seismic loading conditions.
Modulus of Subgrade Reaction Method: Using this method, the pier is designed to resist lateral loads
based on acceptable lateral deflection limits. For sandy soils, the coefficient of horizontal subgrade
reaction (kh) is considered directly proportional to the depth along the pier. The formula to determine kh is
kh = nhx, where x is the depth below the ground surface in inches. Based on a paper by Seed, loose sands
during liquefaction have a residual shear strength equivalent to the horizontal modulus of subgrade reaction
for soft clays. We recommend using values for the constant of horizontal subgrade reaction (nh) for the
various soil layers presented in Table 4 below.
Table 4
Constant of Horizontal Subgrade Reaction (nh)
Depth (feet)
0-2
2-25
25-31.5
0
6
20
Construction Considerations: Due to the granular nature of the site soils and shallow depth to
groundwater, we anticipate that the drilled pier excavations will be prone to raveling and caving.
Therefore, the foundation drilling contractor should be prepared to case the excavation to prevent caving of
the pier shaft sidewalls. If alternative methods of stabilizing the sidewalls are proposed, these should be
reviewed and accepted by the owner, or their representatives, prior to installation.
Additionally, the drilling contractor should be prepared to clean out the bottom of the pier excavation if
loose soil is observed or suspected, with or without the presence of groundwater. As a minimum, we
recommend that the drilling contractor have a cleanout bucket on site to remove loose soils and/or mud
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from the bottom of the pier. If groundwater is present within the pier hole, we recommend that the
foundation concrete be tremied from the bottom of the hole to displace the water and minimize the risk of
contaminating the concrete mix. The Drilled Shaft Manual published by the Federal Highway
Administration recommends that concrete be placed by tremie methods if more than 3 inches of water has
accumulated in the excavation.
Structural Fill
The following comments, recommendations, and conclusions regarding structural fill are provided for
design and construction purposes.
Materials: Structural fill includes any fill materials placed under footings, pavements, driveways, and other
such structures. Typical materials used for structural fill include: clean, well -graded sand and gravel (pit -
run); clean sand; crushed rock; controlled -density fill (CDF); lean -mix concrete; and various soil mixtures
of silt, sand, and gravel. Recycled concrete, asphalt, and glass, derived from pulverized parent materials
are also useful as structural fill.
Placement and Compaction: Generally, CDF, and lean -mix concrete do not require special placement and
compaction procedures. In contrast, pit -run, sand, crushed rock, soil mixtures, and recycled materials
should be placed in horizontal lifts not exceeding 8 inches in loose thickness, and each lift should be
thoroughly compacted with a mechanical compactor. Using the modified Proctor maximum dry density
(ASTM:D-1557) as a standard, we recommend that structural fill used for various on-site applications be
compacted to the following minimum densities:
Fill Application
2H:I V fill slope
Slab/Footing subgrade
Gravel drive subgrade (upper 1 foot)
Gravel drive subgrade (below 1 foot)
Minimum Compaction
95 percent
95 -percent
95 percent
90 percent
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Subgrades and Testing: Regardless of location or material, all structural fill should be placed over firm,
unyielding subgrade soils. We recommend that a PTL/PSI representative be retained to observe the
condition of subgrade soils before fill placement begins, and to perform a series of in-place density tests
during soil fill placement. In this way, the adequacy of soil compaction efforts may be evaluated as
earthwork progresses.
Fill Content: Soils used for structural fill should not contain individual particles greater than about 6
inches in diameter and should be free of organics, debris, and other deleterious materials. Given these
prerequisites, the suitability of soils used for structural fill depends primarily on the grain -size distribution
and moisture content of the soils when they are placed. When the "fines" content (that soil fraction passing
the U.S. No. 200 Sieve) increases, soils become more sensitive to small changes in moisture content. Soils
containing more than about 5 percent fines (by weight) cannot be consistently compacted to a firm,
unyielding condition when the moisture content is more than about 2 percentage points above optimum.
The use of "clean" soil is necessary for fill placement during wet -weather site work. Clean soils are
defined as granular soils that have a fines content of less than 5 percent (by weight) based on the soil
fraction passing the U.S. No. 4 Sieve.
CLOSURE
The conclusions and recommendations presented in this report are based, in part, on the explorations that
we performed for this study. If variations in subsurface conditions are discovered during earthwork, we
may need to modify this report. Because the future performance and integrity of the tower foundations will
depend largely on proper initial site preparation, drainage, and construction procedures, monitoring by
experienced geotechnical personnel should be considered an integral part of the construction process. We
are available to provide geotechnical engineering services during the earthwork and foundation construction
phases of the project. If variations in the subgrade conditions are observed at that time, we would be able
to provide additional geotechnical recommendations, thus minimizing delays as the project develops. We
are also available to review preliminary plans and specifications before construction begins, and to provide
testing services for reinforced concrete and structural steel during construction.
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PACIFIC TESTING LABORATORIES
11324 North Creek Parkway N., #1111
Bothell. WA 9011
206-435-4244
FIGURE 1 -VICINITY MAP
Location:12400 51" Place S.. Tukwila, Washington
Certificate No. 9704-4120
Client: SPRINT SPECTRUNI (SETA -003-07)
Date: 5-6-97
1 B-1 Soil Boring
PACIFIC TESTING LABORATORIES
11324 North Creek Parkway N., #101
Bothell, WA 9011
206-4854244
FIGURE 2 -SITE & EXPLORATION PLAN
Location:12400 51'd Place S., Tukwila, Washington
Certificate No. 9704-4120
Client: SPR.LYT SPECTRUM (SETA -008-07)
Date: 5-6-97
•
PSI (formerly Pac Testing Laboratories)
Engneers • Consultants • Scientists
SPRINT SPECTRUM, L.P.
Project No.: 9704-4120
May 28, 1997
Page 12
APPENDIX A
BORING LOG
EXPLORATION BORING LOG
BORING LOG * B-1
PROSECT:Sprint Spectrum BSNF Intermodal Yard SETA -008-07
DRILLING DATE: Start:5-2-97 CERTIFICATE NO. 9704-4120
Finish:5-2-97
GROUNDWATER DEPTH (ft):18.0
GEOLOGIST:T. Peter
BORING NO.:B-1 ELEVATION(ft):0 SCALECft/Inch):5
DEPTH
SOIL SYMBOLS
SAMPLER SYTMBOLS
AND FIELD TEST DATA
uscs
SOIL DESCRIPTION
REMARKS
PID
ppm
WC
.-0
-5
—1D
—15
—28
—Z5
—30
8/6
10/6
16/6
!7/65/6
1/6
Boring
Continues
Water Checked
5-2-97
15/6
8/56
3/6
6/6
3/6
6/6
6/6
2/6
5;6
28/6
Boring terminated at
approx 18.0 feet. Wa
ML
SM
SM
ML
SP
SP
Asphaltic concrete
Gravel base coarse
Very stiff, moist, brown, sandy SILT
with gravel (fill).
Medium dense, moist, brown, silty
SAND with gravel (fill).
Laose, wet, dark gray, silty fine
SAND.
Medium stiff, saturated, gray -brown
with rust mottling, fine sandy SILT.
Loose, saturated, dark gray, fine to
med SAND some silt. Auger filled w/
water to prevent heave.
Med dense, saturated, dark gray, SAND
trace silt. Blow counts likely
overstated due to heave in sampler.
becomes
stiff
becomes
loose
becomes
saturated
approx. 31.5 feet. Groundwater encountered at
ter level in open boring at 1:30pm was at 11.0 feet
Figure Number A- 1
PACIFIC TESTING LABORATORIES
EXPLORATION BORING LOG
BORING LOG * B-1
PROJECT:Sprint Spectrum BSNF Intermodal Yard SETA -008-07
DRILLING DATE: Start:5-2-97 CERTIFICATE NO. 9704-4120
Finish:5-2-97
GROUNDWATER DEPTH (ft):18.0
GEOLOGIST:T. Peter
BORING NO.:B-1 ELEVATION(ft):0 SCRLE(ft/inch):5
DEPTH
SOIL SYMBOLS
SAMPLER SYMBOLS
AND FIELD TEST DATA
uSCS
SOIL DESCRIPTION
REMARKS
PID
ppm
HC
A
eVS
Boring terminated at
o approx 18.0 feet. Wa
approx. 31.5 feet. Groundwater encountered at
ter level in open boring at 1:30pm was at 11.0 feet
Figure Number A- 2
PACIFIC TESTING LABORATORIES
Legend:
Symbol: Description:
Asphaltic concrete
Symbol: Description:
v� 4
Medium stiff, saturated, gray -brown
with rust mottling, fine sandy SILT.
Laose, wet, dark gray, silty fine
SAND.
Med dense, saturated, dark gray, SAND
trace silt. Blow counts likely
overstated due to heave In sampler.
1----)
Standard penetration
s s test. 140 lb. ham-
mer dropped 30°
Notes:
the boring caved
Rig refusal
end of boring
Gravel base coarse
Water measured at
time indicated
monDepth to which
casing was installed
1. Exploratory boring was drilled on May 2, 1997 using a
4 -inch diameter continuous flight power auger.
2. No free water was encountered at the time of drilling.
3. Boring location was taped from existing features and
elevations extrapolated from the final design schematic plan.
4. This log is subject to the limitations, conclusions, and
recommendations in this report.
5. Results of tests conducted on samples recovered are reported
on the logs. Abbreviations used are:
DD = natural dry density (pcf) LL = Liquid limit
WC = natural moisture content (Z) PI = Plasticity index
UC Unconfined compression (psf) pH = soil pH (Z)
-200 = percent passing #200 sieve (i) SS = Soluable sulfates
SR = Soil resistivity (ohm -cm)
Project No. 9704-4120 Figure Number A- 3
PACIFIC TESTING LABORATORIES