17-105489-Pavement Analysis Report-02.16.23Pavement Analysis
Final Report
Weyerhaeuser Way South
320th Street to 336th Street
Woodbridge Business Park
Federal Way, Washington
for
Federal Way Campus, LLC
January 12, 2023
Pavement Analysis
Final Report
Weyerhaeuser Way South
320th Street to 336th Street
Woodbridge Business Park
Federal Way, Washington
for
Federal Way Campus, LLC
January 12, 2023
1101 South Fawcett Avenue, Suite 200
Tacoma, Washington 98402
253.383.4940
January 12, 2023 | Page i File No. 22247-004-03
Table of Contents
1.0 INTRODUCTION AND PROJECT UNDERSTANDING ............................................................................... 1
2.0 SCOPE OF SERVICES ............................................................................................................................. 1
3.0 SITE CONDITIONS ................................................................................................................................... 1
3.1. Geology Review .................................................................................................................................. 1
3.2. Surface Conditions............................................................................................................................. 2
3.3. Existing Pavement Conditions ........................................................................................................... 2
3.3.1. Design Segments ................................................................................................................... 2
3.3.2. Existing Pavement Sections ................................................................................................... 2
3.3.3. Falling Weight Deflectometer Testing ................................................................................... 3
3.3.4. Visual Condition Survey .......................................................................................................... 3
4.0 PAVEMENT ANALYSIS AND DESIGN ..................................................................................................... 4
4.1. Anticipated Vehicle Loading .............................................................................................................. 4
4.2. Pavement Analysis and Design Parameters .................................................................................... 6
4.2.1. Pavement Design Criteria ...................................................................................................... 6
4.2.2. Subgrade and Material Strength Coefficients ...................................................................... 6
4.3. Design Approach ................................................................................................................................ 6
4.4. Pavement Overlay Considerations and Recommendations ............................................................ 6
4.5. Recommended Pavement Sections.................................................................................................. 7
4.5.1. Segment 1 – South 320th Street to South 323rd Street ...................................................... 7
4.5.2. Segment 2 – South 323rd Street to Midpoint of the Woodbridge Business Park
Development ........................................................................................................................................ 7
4.5.3. Segment 3 – Woodbridge Business Park Development to the South 336th Street
Roundabout .......................................................................................................................................... 7
4.5.4. Segment 4 – South 336th Street Roundabout to Weyerhaeuser Road .............................. 8
4.5.5. Segment 5 – Weyerhaeuser Road to 33rd Place Street Roundabout ................................. 8
4.6. Construction Recommendations ...................................................................................................... 8
5.0 LIMITATIONS .......................................................................................................................................... 9
LIST OF FIGURES
Figure 1. Vicinity Map
Figure 2. Site Plan
APPENDICES
Appendix A. FWD Results and Data
Appendix B. Report Limitations and Guidelines for Use
January 12, 2023 | Page 1
File No. 22247-004-03
1.0 INTRODUCTION AND PROJECT UNDERSTANDING
This geotechnical engineering report presents a summary of our services for the Weyerhaeuser Way
Improvements project in support of the Woodbridge Business Park Property in Federal Way, Washington.
The project will ultimately include roadway improvements on two segments of Weyerhaeuser Way. The
southern section will be from the eastbound State Route (SR) 18 on and off ramps to the roundabout that
connects to 33rd Place South. Analysis of the southern section was provided in our report Geotechnical
Engineering Services Report-Revised, Weyerhaeuser Way South, 320th Street to SR 18, Weyerhaeuser
Campus Property, dated January 30, 2020. The northern section of the project will be from the 33rd Place
South roundabout to South 320th Street. This report addresses the proposed improvements to the northern
section. A Vicinity Map of the approximate project boundaries is provided as Figure 1. A Site Plan is provided
as Figure 2.
We understand that the City of Federal Way (City) has required that: “The applicant must perform pavement
evaluation demonstrating that the standard pavement section for a Type “K” street is adequate to handle
the expected traffic load generating by the proposal.” The City previously provided guidance for the southern
section stating the design criteria should be in accordance with American Association of State Highway and
Transportation Officials (AASHTO) Guide for Design of Pavement Structures (1993) with additional guidance
from Washington State Department of Transportation (WSDOT) Pavement Policy September 2018 for local
data, as applicable.
Based on information provided by ESM Consulting Engineers (ESM) and Transportation Engineering
Northwest (TENW), the proposed traffic with the expected truck load will be based on the existing daily
traffic volume with an additional 293 truck and trailers per day traveling north of the Woodbridge Business
Park (47 northbound and 246 southbound) and an additional 261 truck and trailers per day traveling south
of the Woodbridge Business Park (31 northbound and 230 southbound).
2.0 SCOPE OF SERVICES
Our services for this project have been performed in accordance with our proposal dated October 3, 2022
and signed November 4, 2022. This service entails revising the analysis done previously, but with updated
2019 traffic data provided by TENW.
On December 13, 2022, GeoEngineers, Inc. was requested to expand the original scope of the analysis to
include additional road segments (labeled as Segments 4 and 5 throughout this report, and extending down
to the South 33rd Place roundabout). This expansion of the analysis scope was requested to address
comments from the City.
3.0 SITE CONDITIONS
3.1. Geology Review
We reviewed the Geologic Map of the Poverty Bay 7.5-Minute Quadrangle, King and Pierce Counties,
Washington (Booth, D. B., Waldron, H. H., and Troost, K. G.: U.S. Geological Survey SIM-2854, scale
1:24,000).
January 12, 2023 | Page 2 File No. 22247-004-03
The mapped geologic unit across the entire project area is Vashon till (Qvt). Vashon till deposits are
considered glacially consolidated soils as they were deposited below glacial ice. Glacially consolidated soils
are typically dense to very dense due to being compressed (consolidated) by the weight of the overlaying
glaciers. Glacial till typically consists of a homogenous mixture of silt, sand, gravel, cobbles, and boulders.
3.2. Surface Conditions
Weyerhaeuser Way South is in southeastern Federal Way, Washington. The project area is between the
roundabout at South 33rd Place at the south extent and the intersection of South 320th Street at the north
extent. South 323rd Street connects to the west about 1,100 feet south of 320th Street. The roadway
between South 33rd Place and South 323rd is two traveled lanes, one in each direction, with a paved
shoulder, and no curbs or sidewalks. This portion of the site is generally wooded with occasional driveways.
The roadway between South 323rd and South 320th includes two traveled lanes with a center turn lane,
bike lanes, planter strips, and sidewalks. The west side of the street is developed with commercial buildings.
The east side has one commercial development at the intersection with South 320th Street.
3.3. Existing Pavement Conditions
3.3.1. Design Segments
The project area has been divided into five design segments based on existing pavement conditions,
measured subgrade resilience, and design loading. These segments are grouped in sections north to south,
and follow the convention used for the traffic data provided by TENW:
■ Segment 1 – Extending from South 320th Street to South 323rd Street. Indicated from Station 87+00
to 98+00.
■ Segment 2 – Extending roughly from South 323rd Street to the midpoint of the Woodbridge Business
Park Development. Indicated from Station 64+00 to 87+00.
■ Segment 3 – Extending from roughly the midpoint of the Woodbridge Business Park Development to
the roundabout at South 336th Street. Indicated from Station 50+00 to 64+00.
■ Segment 4 – Extending from south of the roundabout at South 336th Street to Weyerhaeuser Road
■ Segment 5 – Extending from Weyerhaeuser Road to the roundabout at 33rd Place Street.
Note that the referenced stationing indicated in Figure 2 was developed for the pavement study and is not
related to any other stationing developed for geometric roadway design.
3.3.2. Existing Pavement Sections
We reviewed project plans for roadway improvements in the area. Based on plans for the South 336th Street
and Weyerhaeuser Way Roundabout, dated January 30, 2004, new pavement sections consist of 8 inches
asphalt concrete over 6 inches crushed surfacing top course (CSTC). Based on plans for East Campus
Corporate Park Off Site Road Improvements Weyerhaeuser Way South and South 320th Street dated
February 17, 1999, Weyerhaeuser Way consists of a combined overlay with new pavement in widened
areas. The center of the road consisted of a 2.5-inch overlay of the existing asphalt pavement. This overlay
extends over the center turn lane and about half of each travel lane. The widened areas consist of 6 inches
of asphalt concrete over 2 inches of CSTC.
January 12, 2023 | Page 3 File No. 22247-004-03
We did not core the pavement. These thicknesses have not been independently confirmed. We also do not
have information regarding existing pavement thicknesses for the segments between the South 33rd Place
roundabout and South 323rd Street.
3.3.3. Falling Weight Deflectometer Testing
Deflection testing by means of Falling Weight Deflectometer (FWD) was completed by Pavement
Services, Inc. on June 7, 2017. Tests were performed in the north and southbound directions at
approximate 200-foot intervals. Test results were normalized to a 9,000-pound load. A summary of the
back-calculated subgrade modulus and pavement structural numbers for each direction are summarized
in Table 1 below. FWD test data and back-calculations are included in Appendix A of this report.
TABLE 1. FWD RESULTS SUMMARY
Segment and Travel Direction
Average (Mean)
Subgrade Modulus
(Mr) (psi)
Minimum
Subgrade Modulus
(Mr) (psi)
1st Quartile
Subgrade Modulus
(Mr) (psi)
Extending from South 320th Street to South
323rd Street (Northbound) 10,027 6,808 9,524
Extending from South 320th Street to South
323rd Street (Southbound) 11,666 8,967 11,459
Extending roughly from South 323rd Street
to the midpoint of the Woodbridge
Business Park Development (Northbound)
13,593 10,142 11,906
Extending roughly from South 323rd Street
to the midpoint of the Woodbridge
Business Park Development (Southbound)
14,321 8,877 13,450
Extending from roughly the midpoint of the
Woodbridge Business Park Development to
the roundabout at South 336th Street
(Northbound)
9,912 8,031 9,003
Extending from roughly the midpoint of the
Woodbridge Business Park Development to
the roundabout at South 336th Street
(Southbound)
10,076 6,546 9,427
Notes:
psi – pounds per square inch
3.3.4. Visual Condition Survey
We completed an initial visual condition survey of the existing pavement on July 6, 2017. We generally
followed the techniques described in the AASHTO/Federal Highway Administration (FHWA) Pavement
Moisture Accelerated Distress Identification System. On August 10, 2021, we completed a similar visual
condition survey to identify any significant changes from our 2017 evaluation, and then revisited the site
again on January 6, 2023 to observe the current conditions of the newly added segments of the alignment
(4 and 5).
The area from South 336th roundabout to South 323rd Street did not appear to have appreciable or
significant pavement degradation between 2017 and 2021. Although the pavement evaluation was not
January 12, 2023 | Page 4 File No. 22247-004-03
quantitative (i.e., no crack counts with detailed length measurements), the location, type, and severity of
the pavement distress noted was consistent between the 2017 and 2021 surveys. The exception is a few
locations just north of the South 336th Street roundabout where some minor potholes observed in 2017
had been patched and repaired.
Pavement distress in these segments consisted of minor linear cracking with to moderate linear cracking
in isolated areas.
The area from South 323rd Street to South 320th Street did appear to have more degradation since our
2017 survey. In 2017, we noted minor to moderate transverse and lateral cracking. In 2021, we observed
more moderate transverse and lateral cracking that in many locations was transforming into minor block
cracking. Additionally, we noted isolated areas (less than 4 feet in length) of minor to moderate fatigue
cracking with some minor pothole development.
The observed pavement damage was predominantly in the travel lanes. We did not note rutting or extensive
fatigue cracking that would be a sign of extensive subgrade degradation.
The area from South 336th roundabout to South 33rd Place roundabout did appear to present consistent
conditions compared to the roadways to the north, with some minor to moderate transverse and lateral
cracking and one patch with medium block cracking deterioration. Some minor depression along the
roadway was also observed. Again, the observed pavement damage was predominantly in the travel lanes.
We did not note rutting or extensive fatigue cracking that would be a sign of extensive subgrade
degradation.
4.0 PAVEMENT ANALYSIS AND DESIGN
4.1. Anticipated Vehicle Loading
Traffic volumes were provided by TENW. Existing traffic conditions were based on a field traffic count
performed in June 2017. TENW also provided estimated growth rates and the estimated increase in truck
traffic as a result of the proposed development. These estimates include the predicted effects of the
proposed developments. TENW predicts an additional 261 truck trips per day traveling to or from South
336th Street (31 northbound and 230 southbound). These truck trips were applied to design Segment 3,
4, and 5. TENW predicts that the development will result in an additional 293 truck trips per day traveling
to or from South 320th Street (47 northbound and 246 southbound) These truck trips were applied to
design Segments 1 and 2.
The AASHTO design methodology quantifies traffic loading in terms of 18-Kip equivalent single-axle loads
(ESALs). In order to evaluate the pavement and provide a design we converted the traffic estimates to
ESALs. We assumed that every automobile (bicycles, cars, and light trucks) applies an average of
0.0013 ESALs. We assumed that the trucks would be carrying standard shipping containers or similarly
weighted trailers. We used a typical truck weight and a standard distribution of shipping container weights
(developed by Port of Long Beach) to calculate an average loading per truck. Based on this method, we
estimate that every truck applies an average of 1.2 ESALs.
The design ESALs over the entire 20-year design life were determined by projecting the estimated
2023 average daily traffic (ADT) over the design life and adding the contribution from the IRG Realty
January 12, 2023 | Page 5 File No. 22247-004-03
Advisors, LLC (IRG) development. The 2023 ADT was provided by TENW and is based on a 2017 traffic
survey. We assumed that about 1.4 percent of that ADT are trucks. This percent trucks is based on data
from the same 2017 traffic survey. The 2023 baseline was increased by a 2 percent compounding annual
growth rate, as recommended by TENW. The IRG specific loading was added to this assuming no growth
over the same 20-year design life.
The variables provided to us by TENW and the resulting ESAL calculations for a 20-year design period are
summarized in Table 2 below. Based on the data provided, the southbound direction of travel had the most
traffic and the highest portion of trucks. Therefore, we used the southbound data for design in all three
segments.
TABLE 2. DESIGN ESAL SUMMARY (2023 TO 2043)
ADT
(2023)
Assumed
Annual Growth Rate %
Total Vehicles Trips
2023 to 2043 Total ESALS
2023 Cars 3,693 2 34,754,493 45,181
2023 Trucks 52 2 486,563 583,875
IRG Cars 1,028 0 7,879,620 10,244
IRG Trucks 246 0 1,885,590 2,262,708
Segment 1 Design ESALs 2,905,000
2023 Cars 4,095 2 38,537,680 50,099
2023 Trucks 57 2 539,528 647,433
IRG Cars 1,543 0 11,827,095 15,375
IRG Trucks 246 0 1,885,590 2,262,708
Segment 2 Design ESALs 2,980,000
2023 Cars 3,845 2 36,184,952 47,040
2023 Trucks 54 2 506,589 607,907
IRG Cars 1,451 0 11,121,915 14,458
IRG Trucks 230 0 1,762,950 2,115,540
Segment 3 Design ESALs 2,780,000
2023 Cars 5,707 2 53,708,067.80 69,820
2023 Trucks 80 2 751,912.95 902,296
IRG Cars 1,056 0 8,094,240.00 10,523
IRG Trucks 230 0 1,762,950.00 2,115,540
Segment 4 Design ESALs 3,100,000
2023 Cars 5,748 2 54,093,915.14 70,322
2023 Trucks 80 2 757,314.81 908,778
IRG Cars 1,224 0 9,381,960.00 12,197
IRG Trucks 230 0 1,762,950.00 2,115,540
Segment 5 Design ESALs 3,110,000
January 12, 2023 | Page 6 File No. 22247-004-03
4.2. Pavement Analysis and Design Parameters
The pavement design parameters we used in our analyses are summarized below. The parameters we used
for our analysis are based on guidance and data from AASHTO “Guide for Design of Pavement Structures”
1993 (AASHTO), WSDOT “Pavement Policy” September 2018, and the results from the FWD testing.
4.2.1. Pavement Design Criteria
■ Standard Deviation = 0.45 (AASHTO)
■ Reliability = 85 percent (WSDOT)
■ Initial Serviceability = 4.2 (AASHTO)
■ Terminal Serviceability = 2.5 (AASHTO)
4.2.2. Subgrade and Material Strength Coefficients
■ Subgrade Modulus (Mr) is based on 1st Quartile of FWD Data, observations of surface conditions, and
proposed subgrade rehabilitation
Segment 1– 8,500 pounds per square inch (psi)*
Segment 2 – 11,900 psi
Segment 3 (and 4 and 5, due to similar observed surface and geologic conditions) – 9,000 psi
■ Crushed Surfacing Base Course (CSBC) (Mr) = 30,000 psi (WSDOT)
■ CSBC Structural Coefficient = 0.13 (WSDOT)
■ New Asphalt Structural Coefficient =0.45 (WSDOT)
* Although the observed pavement damage is not directly indicative of subgrade deterioration, the design
Mr was reduced from about 9,500 to 8,500 psi in Segment 1 to account for any subgrade damage that
could have occurred after the 2017 FWD testing was performed. We consider this to be conservative.
4.3. Design Approach
We developed a design pavement section in general accordance with AASHTO 1993 “Flexible Pavement
Design Standards” and the design coefficients stated in the previous section. The design pavement section
is based on the assumption that the entire existing pavement section will be removed, the existing subgrade
soils will be evaluated, compacted in place or remediated as necessary, and a new pavement section will
be built on top of the existing or remediated subgrade soils. The design is based on a subgrade modulus
from the lower quartile of FWD data. The weakest sections of subgrade in isolated areas are expected to
be remediated during construction. We also evaluated the design using a subgrade modulus of 2,500 psi,
which is near the lowest value measured in all the FWD data. This was used to estimate the maximum
required overexcavation and subbase thickness.
4.4. Pavement Overlay Considerations and Recommendations
We evaluated the practicality of overlaying the section of Weyerhaeuser Way between South 323rd Street
and South 320th Street considering the current pavement condition, existing design section, and proposed
traffic loading. It is our opinion based on that assessment that an overlay of the travel lanes would not be
January 12, 2023 | Page 7 File No. 22247-004-03
practical. The amount of additional asphalt required to provide an equivalent section would make matching
grades with the existing curbs difficult.
A section of the center turn lane could be rehabilitated with an overlay provided it is practical with
construction staging. The center turn lane was observed to have significantly less damage than the travel
lanes and is expected to have significantly less heavy truck traffic over the design life of the pavement.
An overlay would not be appropriate in the center turn lane used for queuing at the South 320th Street
intersection, the northernmost 350 feet of the roadway.
If an overlay in this area will be used, we recommend a minimum overlay thickness of 2 inches of asphalt.
This can be added to the existing asphalt, or the top of the existing asphalt can be ground down to facilitate
matching existing grades.
4.5. Recommended Pavement Sections
4.5.1. Segment 1 – South 320th Street to South 323rd Street
■ 5.5 inches (0.46 foot) Asphalt Concrete (Minimum Class ½ inch PG58H-22; WSDOT Standard
Specifications 5-04, 9-02, and 9-03).
■ 10 inches (0.83 foot) of CSBC (WSDOT Standard Specification 9-03.9(3)) compacted to 95 percent of
MDD per ASTM D 1557 or to a firm and unyielding condition as indicated by proof-roll observed by
GeoEngineers. Contractor may choose to use CSTC in the upper 2 inches of the section to assist with
grading.
■ 0 to 24 inches (0 to 2 feet) of Aggregate for Gravel Base (WSDOT Standard Specification 9-03.10)
compacted to 95 percent of MDD per ASTM D 1557 or to a firm and unyielding condition as indicated
by proof-roll observed by GeoEngineers.
■ Firm and unyielding subgrade confirmed by proof-roll and/or observation by GeoEngineers.
4.5.2. Segment 2 – South 323rd Street to Midpoint of the Woodbridge Business Park Development
■ 5.5 inches (0.46 foot) Asphalt Concrete (Minimum Class ½ inch PG58H-22; WSDOT Standard
Specifications 5-04, 9-02, and 9-03).
■ 7 inches (0.583 foot) of CSBC (WSDOT Standard Specification 9-03.9(3)) compacted to 95 percent of
MDD per ASTM D 1557 or to a firm and unyielding condition as indicated by proof-roll observed by
GeoEngineers. Contractor may choose to use CSTC in the upper 2 inches of the section to assist with
grading.
■ 0 to 24 inches (0 to 2 feet) of Aggregate for Gravel Base (WSDOT Standard Specification 9-03.10)
compacted to 95 percent of MDD per ASTM D 1557 or to a firm and unyielding condition as indicated
by proof-roll observed by GeoEngineers.
■ Firm and unyielding subgrade confirmed by proof-roll and/or observation by GeoEngineers.
4.5.3. Segment 3 – Woodbridge Business Park Development to the South 336th Street Roundabout
■ 5.5 inches (0.46 foot) Asphalt Concrete (Minimum Class ½ inch PG58H-22; WSDOT Standard
Specifications 5-04, 9-02, and 9-03).
January 12, 2023 | Page 8 File No. 22247-004-03
■ 9.5 inches (0.80 foot) of CSBC (WSDOT Standard Specification 9-03.9(3)) compacted to 95 percent of
maximum dry density (MDD) per ASTM International (ASTM) D 1557 or to a firm and unyielding
condition as indicated by proof-roll observed by GeoEngineers. Contractor may choose to use CSTC in
the upper 2 inches of the section to assist with grading.
■ 0 to 24 inches (0 to 2 feet) of Aggregate for Gravel Base (WSDOT Standard Specification 9-03.10)
compacted to 95 percent of MDD per ASTM D 1557 or to a firm and unyielding condition as indicated
by proof-roll observed by GeoEngineers.
■ Firm and unyielding subgrade confirmed by proof-roll and/or observation by GeoEngineers.
4.5.4. Segment 4 – South 336th Street Roundabout to Weyerhaeuser Road
■ 5.5 inches (0.46 foot) Asphalt Concrete (Minimum Class ½ inch PG58H-22; WSDOT Standard
Specifications 5-04, 9-02, and 9-03).
■ 10.5 inches (0.875 foot) of CSBC (WSDOT Standard Specification 9-03.9(3)) compacted to 95 percent
of MDD per ASTM D 1557 or to a firm and unyielding condition as indicated by proof-roll observed by
GeoEngineers. Contractor may choose to use CSTC in the upper 2 inches of the section to assist with
grading.
■ 0 to 24 inches (0 to 2 feet) of Aggregate for Gravel Base (WSDOT Standard Specification 9-03.10)
compacted to 95 percent of MDD per ASTM D 1557 or to a firm and unyielding condition as indicated
by proof-roll observed by GeoEngineers.
■ Firm and unyielding subgrade confirmed by proof-roll and/or observation by GeoEngineers.
4.5.5. Segment 5 – Weyerhaeuser Road to 33rd Place Street Roundabout
■ 5.5 inches (0.46 foot) Asphalt Concrete (Minimum Class ½ inch PG58H-22; WSDOT Standard
Specifications 5-04, 9-02, and 9-03).
■ 10.5 inches (0.875 foot) of CSBC (WSDOT Standard Specification 9-03.9(3)) compacted to 95 percent
of MDD per ASTM D 1557 or to a firm and unyielding condition as indicated by proof-roll observed by
GeoEngineers. Contractor may choose to use CSTC in the upper 2 inches of the section to assist with
grading.
■ 0 to 24 inches (0 to 2 feet) of Aggregate for Gravel Base (WSDOT Standard Specification 9-03.10)
compacted to 95 percent of MDD per ASTM D 1557 or to a firm and unyielding condition as indicated
by proof-roll observed by GeoEngineers.
■ Firm and unyielding subgrade confirmed by proof-roll and/or observation by GeoEngineers.
Note that the design segment designations or limits are approximate. Adjusting the limits by a few hundred
feet to facilitate construction staging and provide consistency with the construction stages is appropriate
and will likely result in more efficient construction and, therefore, a better final product.
4.6. Construction Recommendations
The subgrade soils must be thoroughly compacted to a uniformly firm and unyielding condition prior to
constructing the roadway section or placing structural fill. We recommend that subgrades be proof-rolled
or probed, as appropriate, to identify areas of yielding or soft soil. Proof-rolling should be accomplished with
January 12, 2023 | Page 9 File No. 22247-004-03
a heavy piece of wheeled construction equipment such as a loaded dump truck or grader. Probing should
be used if proof-rolling is not possible due to site constraints.
If soft or otherwise unsuitable areas are revealed during proof-rolling or probing that cannot be compacted
to a stable and uniformly firm condition, we recommend that: (1) the unsuitable soils be scarified (e.g., with
a ripper or farmer’s disc), aerated and recompacted; or (2) the unsuitable soils be overexcavated and
replaced with compacted aggregate for gravel base, effectively increasing the pavement section.
Overexcavation should extend until uniformly firm soils are encountered as determined by a representative
from our firm.
In our opinion, and based on our analysis and design, overexcavation deeper than about 2 feet is not
required. If a somewhat firm soil (consistent with a Mr of 2,500 psi) is not encountered after 2 feet of
excavation below the subgrade, we recommend that the overexcavation be filled with a crushed aggregate
such as crushed rock base course. If the soil at the base of the overexcavation is wet and compaction
cannot be achieved, we recommend that the overexcavation be filled with Permeable Ballast (WSDOT
Standard Specification 9-03.9(2)).
In our opinion recycled aggregate materials, either derived on site from excavated and processed pavement
sections or imported, are suitable for use as pavement aggregates. All recycled aggregate materials must
meet the gradation and performance specifications for the required aggregates and the WSDOT
specification for Recycled Material (WSDOT Standard Specification 9-03.21).
5.0 LIMITATIONS
We have prepared this report for Federal Way Campus, LLC, for the Weyerhaeuser Way South, 320th Street
to 336th Street Woodbridge Business Park Project located in Federal Way, Washington. Federal Way
Campus, LLC, may distribute copies of this report to owner’s authorized agents and regulatory agencies as
may be required for the Project.
Within the limitations of scope, schedule and budget, our services have been executed in accordance with
generally accepted practices for geotechnical engineering in this area at the time this report was prepared.
The conclusions, recommendations, and opinions presented in this report are based on our professional
knowledge, judgment and experience. No warranty, express or implied, applies to the services or this report.
Please refer to Appendix B, Report Limitations and Guidelines for Use, for additional information pertaining
to use of this report.
FIGURES
µ
SITE
Vicinity Map
Figure 1
Weyerhaeuser Way Pavement EvaluationFederal Way, Washington
2,000 2,0000
Feet
Data Source: Mapbox Open Street Map, 2017
Notes:1. The locations of all features shown are approximate.2. This drawing is for information purposes. It is intended to assist in showing features discussed in an attached document. GeoEngineers, Inc. cannot guarantee the accuracy and content of electronic files. The master file is stored by GeoEngineers, Inc. and will serve as the official record of this communication.
Projection: NAD 1983 UTM Zone 10N
P:\22\22247004\GIS\MXDs\2224700400_F01_NorthSite_VicinityMap.mxd Date Exported: 01/12/23 by glohrmeyer
!(
!(
!(
!(
!(
!(
!(
!(
!(
!(
!(
!(
!(
!(
!(
!(
!(
!(
!(
!(
!(
!(
!(
!(
!(
!(
!(
!(
!(
!(
!(
!(
!(
!(
!(
!(
!(
!(
!(
!(
!(
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
Weyerhaeuser Way S33rd Pl S28+00
78+00
80+00
82+00
74+00
70+00
58+00
52+00
S 3 3 6 th S tS 3 2 3 r d S t
S 3 2 0 t h S t
32nd Ave SI5 SouthboundI5 NorthboundNorth Lake
50+00
54+00
56+00
60+00
62+00
64+00
66+00
68+00
72+00
76+00
84+00
86+00
88+00
90+00
92+00
94+00
96+00
98+00
Site Plan
Weyerhaeuser Way Pavement EvaluationFederal Way, Washington
Figure 2
µ500 0 500
Feet
Legend
FWD A nalysis Point
!(Nor thbound Lane
!(Southbound Lane
E
Approximate P roject Stationing as Established by P avement Services, Inc.
Notes :1. The locations of all features shown are approximate.2. This drawing is for information purposes. It is intended to assist in showing features discussed in an attached document. GeoEngineers, Inc. cannot guarantee the accuracy and content of electronic files. The master file is stored by GeoEngineers, Inc. and will serve as the official record of this communication.
Projection: NAD 1983 StatePlane Washington North FIPS 4601 Feet
P:\22\22247004\GIS\MXDs\2224700400_F02_NorthSitePlan.mxd Date Exported: 01/12/23 by glohrmeyer
Data Source: Aerial from King County 2015
10+00
APPENDICES
APPENDIX A
FWD Results and Data
Project 17091
Index No.Test Station Lane Corrected
Subgrade Mr, psi
Pavement Modulus
(Ep), psi SNeff
34 50+25 NB 9,004 513,396 2.16
35 52+27 NB 10,920 622,304 2.31
36 54+26 NB 8,031 606,008 2.28
37 56+30 NB 10,947 303,913 1.82
39 60+25 NB 10,656 505,613 2.15
41 64+25 NB 10,142 478,084 2.11
42 66+25 NB 16,462 551,108 2.21
44 70+25 NB 15,534 732,925 2.43
45 72+25 NB 15,319 837,291 2.54
47 76+26 NB 13,701 505,035 2.15
49 80+26 NB 14,609 450,290 2.07
50 82+25 NB 12,323 584,581 2.26
52 86+16 NB 10,656 608,479 2.29
53 88+25 NB 6,808 408,587 2.00
54 90+25 NB 10,430 395,344 1.98
55 92+25 NB 11,702 199,132 1.58
56 94+25 NB 11,169 306,771 1.82
59 51+17 SB 6,546 235,012 1.67
60 53+27 SB 10,813 307,866 1.82
61 55+24 SB 9,427 401,870 1.99
62 57+22 SB 11,860 306,771 1.82
64 61+24 SB 11,733 401,870 1.99
66 65+25 SB 16,839 401,870 1.99
68 69+24 SB 8,877 446,652 2.06
69 71+25 SB 14,560 438,917 2.05
70 73+25 SB 13,451 494,628 2.14
72 77+22 SB 16,524 450,290 2.07
73 79+21 SB 16,903 558,560 2.22
74 81+25 SB 15,645 307,866 1.82
75 83+25 SB 11,765 425,009 2.03
76 85+25 SB 14,324 413,797 2.01
77 87+22 SB 12,393 279,702 1.77
78 89+35 SB 8,967 301,862 1.81
79 91+25 SB 11,519 185,560 1.54
80 93+25 SB 13,787 310,700 1.83
81 95+24 SB 11,459 280,811 1.77
Appendix A
FWD Results and Data
320th Street to 336th Street Woodbridge Business Park
Federal Way, Washington
Pavement Services, Inc.
APPENDIX B
Report Limitations and Guidelines for Use
January 12, 2023 | Page B-1 File No. 22247-004-03
APPENDIX B
REPORT LIMITATIONS AND GUIDELINES FOR USE 1
This appendix provides information to help you manage your risks with respect to the use of this report.
Read These Provisions Closely
It is important to recognize that the geoscience practices (geotechnical engineering, geology and
environmental science) rely on professional judgment and opinion to a greater extent than other
engineering and natural science disciplines, where more precise and/or readily observable data may exist.
To help clients better understand how this difference pertains to our services, GeoEngineers includes the
following explanatory “limitations” provisions in its reports. Please confer with GeoEngineers if you need to
know more how these “Report Limitations and Guidelines for Use” apply to your project or site.
Geotechnical Services are Performed for Specific Purposes, Persons and Projects
This report has been prepared for Federal Way Campus, LLC and for the Project(s) specifically identified in
the report. The information contained herein is not applicable to other sites or projects.
GeoEngineers structures its services to meet the specific needs of its clients. No party other than the party
to whom this report is addressed may rely on the product of our services unless we agree to such reliance
in advance and in writing. Within the limitations of the agreed scope of services for the Project, and its
schedule and budget, our services have been executed in accordance with our proposal with Federal Way
Campus, LLC dated October 3, 2022 and signed November 4, 2022 and generally accepted geotechnical
practices in this area at the time this report was prepared. We do not authorize, and will not be responsible
for, the use of this report for any purposes or projects other than those identified in the report.
A Geotechnical Engineering or Geologic Report is based on a Unique Set of Project-Specific
Factors
This report has been prepared for the proposed Weyerhaeuser Way Improvement project in support of the
Weyerhaeuser Way South, 320th Street to 336th Street Woodbridge Business Park Project Washington.
GeoEngineers considered a number of unique, project-specific factors when establishing the scope of
services for this project and report. Unless GeoEngineers specifically indicates otherwise, it is important not
to rely on this report if it was:
■ Not prepared for you,
■ Not prepared for your project,
■ Not prepared for the specific site explored, or
■ Completed before important project changes were made.
1 Developed based on material provided by ASFE, Professional Firms Practicing in the Geosciences; www.asfe.org.
January 12, 2023 | Page B-2 File No. 22247-004-03
For example, changes that can affect the applicability of this report include those that affect:
■ The function of the proposed structure;
■ Elevation, configuration, location, orientation or weight of the proposed structure;
■ Composition of the design team; or
■ Project ownership.
If changes occur after the date of this report, GeoEngineers cannot be responsible for any consequences
of such changes in relation to this report unless we have been given the opportunity to review our
interpretations and recommendations. Based on that review, we can provide written modifications or
confirmation, as appropriate.
Environmental Concerns are Not Covered
Unless environmental services were specifically included in our scope of services, this report does not
provide any environmental findings, conclusions, or recommendations, including but not limited to, the
likelihood of encountering underground storage tanks or regulated contaminants.
Subsurface Conditions Can Change
This geotechnical or geologic report is based on conditions that existed at the time the study was performed.
The findings and conclusions of this report may be affected by the passage of time, by man-made events
such as construction on or adjacent to the site, new information or technology that becomes available
subsequent to the report date, or by natural events such as floods, earthquakes, slope instability or
groundwater fluctuations. If more than a few months have passed since issuance of our report or work
product, or if any of the described events may have occurred, please contact GeoEngineers before applying
this report for its intended purpose so that we may evaluate whether changed conditions affect the
continued reliability or applicability of our conclusions and recommendations.
Geotechnical and Geologic Findings are Professional Opinions
Our interpretations of subsurface conditions are based on field observations from widely spaced sampling
locations at the site. Site exploration identifies the specific subsurface conditions only at those points where
subsurface tests are conducted or samples are taken. GeoEngineers reviewed field and laboratory data
and then applied its professional judgment to render an informed opinion about subsurface conditions at
other locations. Actual subsurface conditions may differ, sometimes significantly, from the opinions
presented in this report. Our report, conclusions and interpretations are not a warranty of the actual
subsurface conditions.
Geotechnical Engineering Report Recommendations are Not Final
We have developed the following recommendations based on data gathered from subsurface
investigation(s). These investigations sample just a small percentage of a site to create a snapshot of the
subsurface conditions elsewhere on the site. Such sampling on its own cannot provide a complete and
accurate view of subsurface conditions for the entire site. Therefore, the recommendations included in this
report are preliminary and should not be considered final. GeoEngineers’ recommendations can be
finalized only by observing actual subsurface conditions revealed during construction. GeoEngineers
January 12, 2023 | Page B-3 File No. 22247-004-03
cannot assume responsibility or liability for the recommendations in this report if we do not perform
construction observation.
We recommend that you allow sufficient monitoring, testing and consultation during construction by
GeoEngineers to confirm that the conditions encountered are consistent with those indicated by the
explorations, to provide recommendations for design changes if the conditions revealed during the work
differ from those anticipated, and to evaluate whether earthwork activities are completed in accordance
with our recommendations. Retaining GeoEngineers for construction observation for this project is the most
effective means of managing the risks associated with unanticipated conditions. If another party performs
field observation and confirms our expectations, the other party must take full responsibility for both the
observations and recommendations. Please note, however, that another party would lack our project-
specific knowledge and resources.
A Geotechnical Engineering or Geologic Report Could Be Subject to Misinterpretation
Misinterpretation of this report by members of the design team or by contractors can result in costly
problems. GeoEngineers can help reduce the risks of misinterpretation by conferring with appropriate
members of the design team after submitting the report, reviewing pertinent elements of the design team’s
plans and specifications, participating in pre-bid and preconstruction conferences, and providing
construction observation.
Do Not Redraw the Exploration Logs
Geotechnical engineers and geologists prepare final boring and testing logs based upon their interpretation
of field logs and laboratory data. The logs included in a geotechnical engineering or geologic report should
never be redrawn for inclusion in architectural or other design drawings. Photographic or electronic
reproduction is acceptable, but separating logs from the report can create a risk of misinterpretation.
Give Contractors a Complete Report and Guidance
To help reduce the risk of problems associated with unanticipated subsurface conditions, GeoEngineers
recommends giving contractors the complete geotechnical engineering or geologic report, including these
“Report Limitations and Guidelines for Use.” When providing the report, you should preface it with a clearly
written letter of transmittal that:
■ Advises contractors that the report was not prepared for purposes of bid development and that its
accuracy is limited; and
■ Encourages contractors to confer with GeoEngineers and/or to conduct additional study to obtain the
specific types of information they need or prefer.
Contractors are Responsible for Site Safety on Their Own Construction Projects
Our geotechnical recommendations are not intended to direct the contractor’s procedures, methods,
schedule or management of the work site. The contractor is solely responsible for job site safety and for
managing construction operations to minimize risks to on-site personnel and adjacent properties.
January 12, 2023 | Page B-4 File No. 22247-004-03
Biological Pollutants
GeoEngineers’ Scope of Work specifically excludes the investigation, detection, prevention or assessment
of the presence of Biological Pollutants. Accordingly, this report does not include any interpretations,
recommendations, findings or conclusions regarding the detecting, assessing, preventing or abating of
Biological Pollutants, and no conclusions or inferences should be drawn regarding Biological Pollutants as
they may relate to this project. The term “Biological Pollutants” includes, but is not limited to, molds, fungi,
spores, bacteria and viruses, and/or any of their byproducts.
A Client that desires these specialized services is advised to obtain them from a consultant who offers
services in this specialized field.