21-100325-Pavement Analysis Report-01-29-2021-V1Earth Science + Technology
Geotechnical Engineering Services Report-
Revised
Weyerhaeuser Way South, 320th Street to SR 18
Weyerhaeuser Campus Property
Federal Way, Washington
for
Federal Way Campus, LLC
January 30, 2020
Geotechnical Engineering Services Report-
Revised
Weyerhaeuser Way South, 320th Street to SR 18
Weyerhaeuser Campus Property
Federal Way, Washington
for
Federal Way Campus, LLC
January 30, 2020
1101 South Fawcett Avenue, Suite 200
Tacoma, Washington 98402
253.383.4940
January 30, 2020| Page i
File No. 22247-004-01
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. Existing Pavement Section ......................................................................................................... 2
3.3.1. Falling Weight Deflectometer Testing ........................................................................................ 2
3.3.2. Visual Condition Survey .............................................................................................................. 2
3.3.3. Pavement Improvements ........................................................................................................... 3
4.0 PAVEMENT ANALYSIS AND DESIGN .............................................................................................................. 3
4.1. Anticipated Vehicle Loading ....................................................................................................................... 3
4.2. Pavement Analysis and Design Parameters ............................................................................................. 4
4.2.1. Pavement Design Criteria ........................................................................................................... 4
4.2.2. Subgrade and Material Strength Coefficients ........................................................................... 4
5.0 PAVEMENT SECTION RECOMMENDATIONS ................................................................................................. 5
5.1. Design Approach ......................................................................................................................................... 5
5.2. Recommended Pavement Section ............................................................................................................ 5
5.3. Construction Recommendations ............................................................................................................... 5
6.0 LIMITATIONS ................................................................................................................................................... 6
LIST OF FIGURES
Figure 1. Vicinity Map
Figure 2. Site Plan
APPENDICES
Appendix A. FWD Results and Data
Appendix B. Visual Condition Survey Summary
Figures B-1 through B-4– Site Photographs
Appendix C. Report Limitations and Guidelines for Use
January 30, 2020| Page 1
File No. 22247-004-01
1.0 INTRODUCTION AND PROJECT UNDERSTANDING
GeoEngineers is pleased to present this geotechnical engineering report for the Weyerhaeuser Way
Improvement project in support of the Weyerhaeuser Campus Property in Federal Way, Washington. The
project will ultimately include roadway improvements on two segments of Weyerhaeuser Way. The southern
segment will be from the eastbound State Route (SR) 18 on and off ramps to the roundabout that connects
to 33rd Place South. This segment will support the development of Warehouses A and B. The northern
segment of the project will be from South 336th Street to South 320th Street. For this phase of the project,
only improvements of the southern segment are being analyzed and designed. A Vicinity Map of the
approximate project boundaries is provided as Figure 1. A Site Plan is provided as Figure 2. The bridge over
SR 18 is not part of this study.
We understand that the City of Federal Way (City) has required that the design team “…perform pavement
analysis per AASHTO along the truck route to ensure the existing pavement can accommodate the expected
truck load.” The City has further clarified in a May 3, 2019 email from Sarady Long that the design criteria
shall 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 and TENW the proposed traffic with the expected truck load will be
based on the existing daily traffic volume with an additional 500 truck and trailers per day (250 in either
direction).
2.0 SCOPE OF SERVICES
Our services for this project were initiated by a Confirming Agreement dated and signed June 14, 2017.
These services included investigating the existing condition of the pavement, estimating remaining design
life of the pavement, and to providing recommendations for pavement improvements or overlays. This
analysis was provided in a Geotechnical report dated August 29, 2017. This revised report updates the
previous report and presents analysis of only the proposed pavement section, as requested. Our services
have been provided in general accordance with our signed Confirming Agreement and an addendum dated
March 26, 2019 and executed April 1, 2019.
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).
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.
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File No. 22247-004-01
3.2. Surface Conditions
Weyerhaeuser Way South is in southeastern Federal Way, Washington; the project area discussed in this
report is between 33rd Place South on the north side and the SR 18 eastbound on and off ramps. The
roadway is two traveled lanes in each direction with a left-turn lane and is bordered with concrete gutters
on the east and west edges over a majority of the site. The southern portion of Weyerhaeuser Way South
crosses over SR 18 with an approximate 200-foot span overpass. The site is generally level with a slight
increase in elevation as the road progresses south near the SR 18 overpass section of the road and the
elevation decreases south of the overpass. The overall topography of the surrounding area slopes
downward from the southwest to the northeast. The lower side of the slope on the west side of the road is
well below the roadway elevation; indicating portions of the west side of the road was constructed on fill.
3.3. Existing Pavement Conditions
3.3.1. Existing Pavement Section
Based on plans from the most recent construction, dated August 25, 1999, on Weyerhaeuser Way South
the existing pavement has two different profiles. The inside (left) lanes have 2.5 inches of newer asphalt
overlaying the previous asphalt section, while the outer (right) lanes have 6 inches of asphalt underlain by
a 2-inch thick base coarse. We did not core the pavement. These thicknesses have not been independently
confirmed.
3.3.1. Falling Weight Deflectometer Testing
Deflection testing by means of Falling Weight Deflectometer (FWD) was completed by Pavement Services
Inc. (PSI) on June 7, 2017. Tests were performed in the left and right lanes 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 lane in 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
Travel Direction and Lane Average (Mean) Subgrade
Modulus (Mr) (psi)
Minimum Subgrade
Modulus (Mr) (psi)
1st Quartile Subgrade
Modulus (Mr) (psi)
Northbound Right Lane 7,600 5,700 6,500
Northbound Left Lane 9,100 2,500 8,400
All Northbound 8,500 2,500 7,000
Southbound Right Lane 10,000 8,100 8,900
Southbound Left Lane 10,000 6,800 8,400
All Southbound 10,000 6,800 8,500
Full Segment 9,200 2,500 8,200
3.3.2. Visual Condition Survey
We completed a 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.
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File No. 22247-004-01
The primary types of pavement distress observed in our visual survey included: fatigue (alligator) cracking,
depressions, longitudinal cracking, patch deterioration, and potholes. Table B-1 in Appendix B summarizes
the severity of distress observed along Weyerhaeuser Way South during our visual survey. Definitions of
the different distress types are provided in Table B-2 and photos showing examples of some of the distress
types observed are provided as Figure B-1 through Figure B-4 in Appendix B.
Based on our evaluation, it is our opinion that average section of existing pavement is showing signs of
“medium” distress severity with some isolated areas showing signs of “high” distress. Based on AASHTO
criteria, this is consistent with asphalt that is on average about 60 to 70 percent the strength and resilience
of new asphalt. This is consistent with the measurements made from the FWD testing. As a comparison,
crushed rock or completely deteriorated asphalt still provides about 30 percent of the strength and
resilience of new asphalt.
Little to no rutting was observed with exception of the pavement surrounding a manhole located about
150 feet north of the eastbound off-ramp in the right-hand turn lane. Moderate to severe rutting was
observed in this area. The rutting surrounding the manhole is likely due to deeper depths of under
compacted fill, leading to isolated settlement of the pavement subgrade in these areas.
3.3.3. Pavement Improvements
A pavement rehabilitation project was completed by the City in the summer of 2018. This pavement
rehabilitation included full depth replacement of pavement in some wheel paths. We understand based on
conversations with City personnel that the subgrade in the full depth replacement areas was soft and
degraded.
On May 10, 2019 we observed the pavement and compared our observations to our July 2017 evaluation.
Almost all the areas identified as “high” distress in our initial evaluation had been repaired. Some small
areas of fatigue cracking were observed just beyond the freshly patched areas. Longitudinal cracks did not
appear to have been sealed.
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 from June 13, 2017 to June 20, 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 both the Warehouse A and B sites.
The AASHTO design methodology quantifies traffic loading in terms of 18-Kip 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.
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File No. 22247-004-01
The existing daily traffic counts shows that trucks make up 3.8 percent of the total daily traffic. Based on
guidance from TENW we assumed the proposed traffic would increase by an additional 500 trucks
(250 each way) per day.
It is common to include a growth rate for existing traffic counts to account for typical increase of traffic over
the design life. Because the proposed development will cause additional traffic on top of the additional
truck traffic, a higher growth than typical rate was used to determine the ESALs.
The estimated ESALs over the entire design life were determined by calculating the current daily ESAL value,
based on the existing traffic counts, and extending the daily value over a 20-year design life with the
corresponding growth rates and increase in truck traffic.
The variables provided to us by TENW and the resulting ESAL calculations for a 20-year design period are
summarized in Table 2 below.
TABLE 2. DESIGN ESAL SUMMARY
Design Condition Total Daily Traffic
(One Way)
Daily Truck Traffic
(One Way)
Growth
Rate
Total EASLs
(20 years)
Anticipated Traffic with Proposed
Development 11,860 450 4% 8,760,000
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) = 8,200 pounds per square inch (psi) (Based on 1st Quartile of FWD Data and
proposed subgrade rehabilitation)
■ Crushed Surfacing Base Course (Mr) = 30,000 psi (WSDOT)
■ Crushed Surfacing Base Course Structural Coefficient = 0.13 (WSDOT)
■ New Asphalt Structural Coefficient =0.45 (WSDOT)
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File No. 22247-004-01
5.0 PAVEMENT SECTION RECOMMENDATIONS
5.1. 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 of
8,200 pound per square inch (psi), which is lower quartile of FWD data. We anticipate that weakest sections
of subgrade have already been remediated to some extent during the 2018 pavement rehabilitation
project. Additional remediation may be required. We also evaluated the design using a subgrade modulus
of 2,200 psi, which is lower than the lowest value measured in the FWD data. This was used to estimate
the maximum required overexcavation.
5.2. Recommended Pavement Section
■ 6.5 inches (0.54 foot) Asphalt Concrete (Minimum Class ½ inch PG58H-22; WSDOT Standard
Specifications 5-04, 9-02, and 9-03).
■ 12 inches (1.0 foot) of Crushed Surfacing Base Course (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 Crushed Surfacing Top Course 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.
5.3. 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
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 2,200 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
January 30, 2020| Page 6
File No. 22247-004-01
cannot be achieved, we recommend that the overexcavation be filled with Permeable Ballast (WSDOT
Standard Specification 9-03.9(2)).
6.0 LIMITATIONS
We have prepared this report for Federal Way Campus, LLC, for the Weyerhaeuser Way South, 320th Street
to SR 18 Weyerhaeuser Campus Property 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 C titled “Report Limitations and Guidelines for Use” for additional information
pertaining to use of this report.
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
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Figure 2
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Approximate Project Stationing as Established by Pavement 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_SouthSitePlan.mxd Date Exported: 07/28/17 by cchelf
Data Source: Aerial from King County 2015
10+00
APPENDIX A
FWD Results and Data
Weyerhaeuser WayFederal Way, WAAASHTO Backcalculation Analysis ResultsProject No. 17019Index No.Test Station LaneCorrected Subgrade Mr, psiPavement Modulus (Ep), psiSNeff1 11+00 NB LL 13,830174,9051.512 14+98 NB RL 9,570643,0672.333 15+02 NB LL 12,714213,2611.614 16+55 NB RL 7,197245,5031.695 17+00 NB LL 8,277204,8161.596 18+00 NB RL 6,450-28,074-0.827 19+00 NB LL 8,452163,9461.488 20+00 NB RL 5,700255,5861.719 21+00 NB LL 8,788386,5801.9710 22+11 NB RL 8,8471,065,9182.7613 25+00 NB LL 9,115624,4152.3115 27+00 NB LL 2,527762,9862.4717 10+76 SB LL 15,870192,6181.5618 11+09 SB RL 13,874179,9661.5219 14+59 SB LL 9,308424,9242.0320 16+33 SB LL 10,165167,6801.4921 17+00 SB RL 10,708138,4571.4022 18+00 SB LL 9,427216,7731.6223 19+00 SB RL 9,848111,4131.3024 20+00 SB LL 8,528669,1942.3626 22+00 SB LL 9,529341,4661.8928 23+99 SB LL 6,836812,8042.5229 25+00 SB RL 8,0901,369,4783.0031 27+00 SB RL 8,1901,039,7432.7433 29+01 SB RL 9,1151,144,2062.82Pavement Services, Inc.
APPENDIX B
Visual Condition Survey Summary
January 30, 2020| Page B-1
File No. 22247-004-01
APPENDIX B
VISUAL CONDITION SURVEY SUMMARY
Table B-1 below summarizes the primary pavement distress types we observed during our visual condition
survey performed on July 6, 2017. Definitions of different distress types for asphalt concrete are provided
in Table B-2. The distress definitions are taken from the Federal Highway Administration (FHWA) Distress
Identification Manual (Publication No. FHWA-RD-03-031, June 2003). Photographs of some of the distress
types are provided as Figure B-1 through Figure B-4.
TABLE B-1. OBSERVED PAVEMENT DISTRESS
Observed Distress
■ Low to severe fatigue cracking*
■ Low depression
■ Low to severe longitudinal and transverse cracking*
■ Low to moderate patch deterioration
■ Low to moderate potholes*
■ Moderate rutting near storm drain*
Note:
* Photos of distress provided in Figure B-1 through Figure B-4 in Appendix B.
TABLE B-2. ASPHALT CONCRETE DISTRESS DEFINITIONS
Distress Type Definition
Fatigue Cracking A series of small, jagged, interconnecting cracks caused by failure of the AC surface
under repeated traffic loading (also called alligator cracking).
Depression Localized pavement surface areas with elevation slightly lower than those of the
surrounding pavement.
Longitudinal Cracking Cracking parallel to the centerline of the pavement.
Patch Deterioration Distress occurring within a previously repaired area.
Potholes A bowl-shaped hole of various sizes in the pavement surface.
Rutting Longitudinal surface depressions in the wheel paths.
Figure B-1
Pavement Distress Photo:
Fatigue Cracking of AC Pavement
Weyerhaeuser Way South
Federal Way, Washington
22247-004-00 Date Exported: 080417
Figure B-2
Pavement Distress Photo:
Longitudinal Cracking
22247-004-00 Date Exported: 080417Weyerhaeuser Way South
Federal Way, Washington
Figure B-3
Pavement Distress Photo:
Potholes
Weyerhaeuser Way South
Federal Way, Washington
22247-004-00 Date Exported: 080417
Figure B-4
Pavement Distress Photo:
Rutting/Settlement
22247-004-00 Date Exported: 080417Weyerhaeuser Way South
Federal Way, Washington
APPENDIX C
Report Limitations and Guidelines for Use
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File No. 22247-004-01
APPENDIX C
REPORT LIMITATIONS AND GUIDELINES FOR USE1
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 Agreement with Federal Way
Campus, LLC dated June 14, 2017 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 SR 18, Weyerhaeuser Campus Property in Federal Way,
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 30, 2020| Page C-2
File No. 22247-004-01
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
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File No. 22247-004-01
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 30, 2020| Page C-4
File No. 22247-004-01
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.