25001_dynatech II_Geotechnical Report - Toomey Avenue Multifamily Project, Charlotte, NC 011921

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GEOTECHNICAL REPORT

Toomey Avenue Multifamily Project
2207-2315 Toomey Avenue
Charlotte, North Carolina 28203

January 19, 2021
Partner Project Number: 20-296889.2
Prepared for:
Abacus Capital
1200 E. Morehead Street, Suite 280
Charlotte, North Carolina 28203

800-419-4923 www.PARTNEResi.com
January 19, 2021
Mr. Mason Ellerbe
Abacus Capital
1200 E. Morehead Street, Suite 280
Charlotte, North Carolina 28204
Subject: Geotechnical Report
2207-2315 Toomey Avenue
Charlotte, North Carolina 28203
Partner Project No. 20-296889.2
Dear Mason Ellerbe:
Partner Assessment Corporation (Partner) presents the following general opinion regarding the
geotechnical conditions at the subject site, based on the information contained within this geotechnical
report and our general experience with construction practices and geotechnical conditions on other sites.
This statement does not constitute an engineering recommendation.
• The geotechnical conditions on the site related to the planned construction are expected to be similar to
more difficult in comparison with other similar sites*; given challenges associated with the presence of the
undocumented fill, and moderate to high plasticity silt and clay material. We recommend supplemental
test pits be performed at the site to evaluate the extents of the undocumented fill.
The descriptions and findings of our geotechnical report are presented for your use in this electronic format,
for your use as shown in the hyperlinked outline below. To return to this page after clicking a hyperlink,
hold “alt” and press the “left arrow key” on your keyboard.
1.0 Geotechnical Executive Summary
2.0 Report Overview and Limitations
3.0 Geologic Conditions and Hazards
4.0 Geotechnical Exploration and Laboratory Results
5.0 Geotechnical Recommendations
Figures & Appendices
We appreciate the opportunity to be of service during this phase of the work.
Sincerely,

Matthew Marcus Siamak Koochak, PE
Principal Engineer Project Geotechnical Engineer

* “similar sites” refers to sites with similar planned and current use, where we have recently performed similar work, and
is a general statement not based on statistical analysis.

Geotechnical Report
Project No. 20-296889.2
January 19, 2021
Page 1
1. GEOTECHNICAL EXECUTIVE SUMMARY
The executive summary is meant to consolidate information provided in more detail in the body of this
report. This summary in no way replaces or overrides the detailed sections of the report.
Geologic Zones and Site Hazards
The subject property is situated in City of Charlotte within the Piedmont physiographic province of the State
of North Carolina. The site grades vary significantly based on natural hilly topography and previous grading
activities. According to historical aerial photos and topographic maps, the site was undeveloped land before
1931. During the 1940s and years later, there have been construction/demolition activities on the different
parts of the site. As such the site may be impacted by buried utility lines, undocumented fills, and remnants
of previous foundation, agriculture and vegetation. This area is prone to low to moderate ground shaking.
The site is not mapped within a FEMA flood zone. No other geologic hazards are known or suspected on
the site.
Excavation Conditions
According the proposed grading plan, there will up to about 15 feet of mass grading needed to establish
finished grades on the site in the buildings area. As previously mentioned, undocumented fills, and
remnants of previous construction and agricultural activities and tree roots may be present on the site and
could cave or be difficult to remove and require additional planning and equipment. Groundwater was
encountered at the depths from about 10 to 24 feet during our investigation. However, groundwater levels
fluctuate over time and may be different at the time of construction and during the project life and the
contractor should be prepared to manage groundwater in deeper excavations. Partially weathered rock
(PWR) was encountered as shallow as 15 feet on the site and could slow excavations if encountered. Partner
was conducting sampling for environmental conditions at the time of our report. This should be reviewed.
Foundation/Slab Support
As previously described, mass grading is expected to take place on the site. This will include the removal of
old fills, soil stockpiles, trees and vegetation, and existing remnants of old structures. After the removal of
all the old fills, preparation of compentent native soil, and replacment with compacted fill (as described in
Section 5) we recommend that the new site structues be supported on spread foundations with concrete
slabs on grade. Highly plastic clay and/or silt soils (CH/MH) should not be used within the upper 5 feet of
fills below new buildings.
Soil Reuse
Based on our borings, site soils will generally be unsuitable for reuse as engineered fill in structural areas,
given the moderate to high plasticity of the clay and silt soils. We anticipate import or borrow of granular
soil will be needed. We recommend engineered fill below slabs and foundations for the site consist of soil
with a plasticity index less than 10 and that is free of deleterious material. We recommend engineered fill
for the site should be moisture conditioned and compacted to at least 95% of the maximum dry density in
accordance with ASTM D 698 and Appendix C of this report.
Pavement Design
Roadway Type Subgrade Preparation Pavement Section
Parking Area Light Duty (Vehicles) Proof rolled/Compacted Subgrade 3 in. Asphalt / 8 in. Aggregate Base
Drive Lanes Heavy Duty (Vehicles) Proof rolled/Compacted Subgrade 4 in. Asphalt / 10 in. Aggregate Base
Trash Enclosure/ Dumpster Pad Proof rolled/Compacted Subgrade 8 in. Concrete/ 6 in. Aggregate Base

Geotechnical Report
Project No. 20-296889.2
January 19, 2021
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2. REPORT OVERVIEW & LIMITATIONS
2.1 Report Overview
Existing readily available information and site-specific data from our exploration program was used to
develop this report. Recommendations for construction and construction considerations to guide the
methods of site development are based on standard industry practices and our experience on previous
projects. The opinions presented on the cover letter of this report do not constitute engineering
recommendations, and are only general, based on our recent anecdotal experiences and not statistical
analysis. Section 1.0, Geotechnical Executive Summary, compiles data from each of the report sections, while
each of sections in the report presents a detailed description of our work. The detailed descriptions in
Section 5.0 and Appendix C constitute our engineering recommendations for the project, and they
supersede the Geotechnical Executive Summary.
The report overview, including a description of the planned construction and a list of references, as well as
an explanation of the report limitations is provided in Section 2.0. The findings of our geologic review are
included in Section 3.0 Geologic Conditions & Hazards. The descriptions of our methods of exploration and
testing, as well as our findings are included in Section 4.0 Geotechnical Exploration & Laboratory Results. In
addition, logs of our exploration excavations are included in Appendix A of the report, and laboratory testing
is included in Appendix B of the report. Site Location and Site Plan maps are included as Figures in the
report.
2.2 Proposed Construction
Our understanding of the planned construction was based on information provided by the project team.
The proposed site plan is included as Figure 2 to this report. Assumptions regarding the new construction
are presented in the below table.
Property Data
Planned Use: Multi-Family Housing
Building footprint/height 244 Residential Units: approximately 3 Complexes ~30,000 ft sf/four-stories and 1
Amenity Area approximately 4,500 sf/single-story
Land Acreage (Ac): Approximately 8.7 acres
Number of Buildings: 4
Expected Cuts and Fills Up to about 9 feet of cuts and about 7 feet of fills in the building area
Type of Construction: Unknown, assumed slab on grade with lightweight wood framing
Foundations Type Unknown, assumed slab on grade and/or conventional spread foundations
Anticipated Loads Unknown, assumed 400-kip column loads and 6-7 kips/ft wall loads
Traffic Loading Unknown, assumed primarily vehicular and occasionally heavy truck traffic
Site Information Sources: Google Earth Pro and 2213 Toomey Ave. Coordination Exhibit (EX-A) prepared by
McAdams dated 12/23/2020

Geotechnical Report
Project No. 20-296889.2
January 19, 2021
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2.3 References
The following references were used to generate this report:
Federal Emergency Management Agency, FEMA Flood Map Service Center, accessed 1/5/21
Google Earth Pro (Online), accessed 1/5/21
Historic Aerials by NETR Online, accessed 1/5/21
United States Department of Agriculture, Web Soil Survey, accessed online 1/5/21
United States Geological Survey, North Carolina Interactive Geologic Map accessed 1/5/21
United States Geological Survey, Lower 48 States 2014 Seismic Hazard Map, accessed online 1/5/21
United States Geologic Survey, Earthquake Hazards Program (Online), accessed 1/5/21
Partner Engineering and Science, Inc., Phase 1 Environmental Site Assessment, Toomey Avenue Multifamily
Project, Charlotte, North Carolina, Report dated 12/14/20
2.4 Limitations
The conclusions, recommendations, and opinions in this report are based upon soil samples and data
obtained in widely spaced locations that were accessible at the time of exploration and collected based on
project information available at that time. Our findings are subject to field confirmation that the samples
we obtained were representative of site conditions. If conditions on the site are different than what was
encountered in our borings, the report recommendations should be reviewed by our office, and new
recommendations should be provided based on the new information and possible additional exploration if
needed. It should be noted that geotechnical subsurface evaluations are not capable of predicting all
subsurface conditions, and that our evaluation was performed to industry standards at the time of the study,
no other warranty or guarantee is made.
Likewise, our document review and geologic research study made a good-faith effort to review readily
available documents that we could access and were aware of at the time, as listed in this letter. We are not
able to guarantee that we have discovered, observed, and reviewed all relevant site documents and
conditions. If new documents or studies are available following the completion of the report, the
recommendations herein should be reviewed by our office, and new recommendations should be provided
based on the new information and possible additional exploration if needed.
This report is intended for the use of the client in its entirety for the proposed project as described in the
text. Information from this report is not to be used for other projects or for other sites. All of the report
must be reviewed and applied to the project or else the report recommendations may no longer apply. If
pertinent changes are made in the project plans or conditions are encountered during construction that
appear to be different than indicated by this report, please contact this office for review. Significant
variations may necessitate a re-evaluation of the recommendations presented in this report. The findings in
this report are valid for one year from the date of the report. This report has been completed under specific
Terms and Conditions relating to scope, relying parties, limitations of liability, indemnification, dispute
resolution, and other factors relevant to any reliance on this report.

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Project No. 20-296889.2
January 19, 2021
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If parties other than Partner are engaged to provide construction geotechnical services, they must be
notified that they will be required to assume complete responsibility for the geotechnical phase of the
project by concurring with the findings and recommendations in this report or providing alternate
recommendations.

Geotechnical Report
Project No. 20-296889.2
January 19, 2021
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3. GEOLOGIC CONDITIONS & HAZARDS
This section presents the results of a geologic review for the proposed new construction on site. The general
location of the project is shown on Figure 1.
3.1 Site Location and Project Information
The planned construction will consist of an approximate 34,500-sf one to four-story structures on an
approximate 8.7-acre parcel of land located within residential and mixed-commercial area of Charlotte,
North Carolina. The project site is bordered by residential houses to the north, Toomey Avenue to the west,
W. Tremont Avenue to the south and an undeveloped/vegetated land to the east. Figure 2 presents the
project site and the locations of our explorations. Based on our review of available documents, the site has
had the following previous uses:
Historical Use Information
Period/Date Source Description/Use
1905 – 1907 Topographic Maps Undeveloped Land
1931 – 1993 Aerial Photographs, City Directories, Previous
Report, Topographic Maps
Commercial (Plumbing Supplier/Shoemaker),
Single-Family Residential, and/or Undeveloped
Land
1994 – 2014 Aerial Photographs, City Directories, Previous
Report
Light Industrial (Fencing & Grading Contractor)
& Single-Family Residential
2015 – 2018 Aerial Photographs, Agency Records, City
Directories, Interviews
Light Industrial (Fleet Maintenance) and
Commercial Office
2019 – Present Agency Records, City Directories, Interviews,
Onsite Observations
Commercial (Fitness/Martial Arts Training) and
Commercial Office
3.2 Geologic Setting
The subject property is situated in City of Charlotte within the Piedmont physiographic province of the State
of North Carolina. This province consists mainly of rolling, well-rounded hills and ridges with a few hundred
feet of difference in elevation between the valleys and hills. The site grades are gently sloping upwards
along the Toomey Avenue toward the center of the site and sloping downward from the center toward the
southwest corner of the site. Similarly, the site grade moderately sloping downwards from the southeast
corner to the northwest corner. According to historical aerial photos and topographic maps, the site has
been historically undeveloped land before 1931. During 1940s and years later, there have been
construction/demolition activities on the different parts of the site. As such the site may be impacted by
buried utility lines, undocumented fills, and remnants of previous foundation, agriculture and vegetation.
This area is prone to low to moderate ground. The site is not mapped within a FEMA flood zone. No other
geologic hazards are known or suspected on the site.
Based on information obtained from the United States Department of Agriculture (USDA) Natural Resources
Conservation Service Web Soil Survey online database, the subject property is mapped as Cecil-Urban land
complex. The Cecil series consists of very deep, well drained soils that formed in saprolite derived from

Geotechnical Report
Project No. 20-296889.2
January 19, 2021
Page 6
granite, gneiss, and/or schist. These soils are found on interfluves and hillslopes on ridges. Slopes range
from 2 to 15 percent. Urban land consists of areas where more than 85 percent of the surface is covered by
buildings, roads, and other structures. The soils in these areas have been greatly disturbed and may vary
widely in characteristics.
A general summary of the geologic data compiled for this project is provided in the below table.
Geologic Data
Parameter Value Source
Physiographic Province Piedmont USGS
Ground Elevation Approx. 664 top 799 feet above Mean Sea Level USGS
Flood Elevation Floodway Zone X FEMA
Seismic Hazard Zone Low to Moderate USGS
Geologic Hazards Ground Shaking USGS
Surface Cover Topsoil/vegetation Partner Borings
Surficial Geology Granodiorite and related granitoids USGS
Groundwater Depth Approx. 10 to 24 feet Partner Borings
3.3 Geologic Hazards
Geologic hazards with the potential to affect development in North Carolina are expansive soil, earthquakes,
sinkholes, landslides, abandoned oil and gas wells, and abandoned and/or collapsed mine. Additionally, this
region of North Carolina is not known to be susceptible to sinkhole activity and not within a region known
for oil and gas wells. The site is not within proximity to a known mine. Expansive soils are not a site risk.
North Carolina is generally considered to have a low to moderate seismic risk per the USGS 2014 Hazard
Risk Map. Additionally, this area is rural, and composed of relatively flat terrain that is not at a high-risk for
landslide activity. In accordance with the American Society of Civil Engineers (ASCE), document 7-16,
earthquake design accelerations from the USGS website are provided below.
Seismic Item Value Seismic Item Value
Site Classification D Seismic Design Category B
Fa 1.6 Fv 2.4
Ss 0.201g S1 0.082g
SMS 0.322g SM1 0.198g
SDS 0.215g SD1 0.132g
MCEG PGA 0.103g Design PGA (2/3 of MCEG) 0.068g

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Project No. 20-296889.2
January 19, 2021
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4. GEOTECHNICAL EXPLORATION & LABORATORY RESULTS
Our evaluation of soils on the site included field exploration and laboratory testing. The field exploration
and laboratory testing programs are briefly described below. Data reports from the field exploration and
laboratory testing are provided in Appendix A and Appendix B, respectively.
4.1 Soil Borings
Subsurface materials and conditions at the site were investigated on January 7 through January 8, 2021. Ten
(10) borings designated B-1 through B-10 were advanced using a track mounted Dietrich D-50 drill rig
equipped with automatic hammer and hollow-stem auger drilling techniques. The borings were advanced
to depths ranging from approximately 20 feet 3 inches to 31.5 feet below the ground surface. The general
location of the exploratory borings is shown on Figure 2.
Logs of encountered subsurface conditions were recorded during soil boring activities. Standard
Penetration Tests (SPT) were performed at approximately 2.5 and 5-foot depth intervals in accordance with
ASTM D 1586. Soil samples were collected during the SPT and returned to our laboratory for testing. Typed
boring logs were prepared from the field logs and are presented in Appendix A. A summary table of
materials encountered is provided below:
Surficial Geology
Strata Depth to Bottom of Layer (bgs*) Description
Surface Cover Approx. 6 inches Vegetation/Topsoil
Undocumented Fill Approx. 10 to 15 feet Partner Borings B-1, B-3, and B-4 only
Native Stratum 1 Approx. 30 feet+ SAND (SM) – Partner Boring B-3 only
Native Stratum 2 Approx. 7 to 31.5 feet+ CLAY (CL) and SILT (ML/MH)
Groundwater Approx. 10 to 24 feet Partner Borings
Partially Weathered Rock Approx. 20 feet+ to 31.5 feet+ Partner Boring B-2, B-4, B-5, B-9, and B-10
*bgs – below ground surface
4.2 Groundwater
Groundwater was encountered at depths ranging from about 10 feet to 24 feet below the ground surface
at the time of our investigation. Groundwater was encountered at a shallower depth, approximately 10 feet
below the ground surface (corresponding to about el. +657) within the north area of the site, and at a depth
of about 24 feet below the ground surface (corresponding to about el. +657) in Boring B-5. However,
groundwater levels fluctuate over time and may be different at the time of construction and during the
project life.
4.3 Laboratory Evaluation
Selected samples collected during drilling activities were tested in the laboratory to assist in evaluating
engineering properties of subsurface materials at the site. The results of laboratory analyses are presented
in Appendix B.

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January 19, 2021
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5. GEOTECHNICAL RECOMMENDATIONS & PARAMETERS
The following discussion of findings for the site is based on the assumed construction, geologic review,
results of the field exploration, and laboratory testing programs. The recommendations of this report are
contingent upon adherence to Appendix C of this report, General Geotechnical Design and Construction
Considerations. For additional details on the below recommendations, please see Appendix C.
5.1 Geotechnical Recommendations
The proposed construction is generally feasible from a geotechnical perspective provided the
recommendations and assumptions of this report are followed.
Geologic/General Site Considerations
• The subject property is situated in City of Charlotte within the Piedmont physiographic province of
the State of North Carolina. The site grades vary significantly based on natural hilly topography and
previous grading activities. According to historical aerial photos and topographic maps, the site was
undeveloped land before 1931. During the 1940s and years later, there have been
construction/demolition activities on the different parts of the site. As such the site may be
impacted by buried utility lines, undocumented fills, and remnants of previous foundation,
agriculture and vegetation. This area is prone to low to moderate ground shaking. The site is not
mapped within a FEMA flood zone. No other geologic hazards are known or suspected on the site.
• Given the location of the site in the mid-Atlantic region, consideration should be given to weather
conditions at the time of grading. Earthwork should be scheduled during seasonally dry periods
and/or proper preparations should be made to deal with rain events, tropical storms, winter storms,
etc.
Excavation Considerations
• According the proposed grading plan, there will up to about 15 feet of mass grading needed to
establish finished grades on the site in the buildings area. As previously mentioned, undocumented
fills, and remnants of previous construction and agricultural activities and tree roots may be present
on the site and could cave or be difficult to remove and require additional planning and equipment.
Groundwater was encountered at the depths from about 10 to 24 feet during our investigation.
However, groundwater levels fluctuate over time and may be different at the time of construction
and during the project life and the contractor should be prepared to manage groundwater in
deeper excavations. Partially weathered rock (PWR) was encountered as shallow as 15 feet on the
site and could slow excavations if encountered. Partner was conducting sampling for environmental
conditions at the time of our report. This should be reviewed.
• Groundwater was encountered at depths ranging from about 10 feet to 24 feet below the ground
surface at the time of our investigation. Groundwater was encountered at a shallower depth,
approximately 10 feet below the ground surface (corresponding to about el. +657) within the north
area of the site, and at a depth of about 24 feet below the ground surface (corresponding to about

Geotechnical Report
Project No. 20-296889.2
January 19, 2021
Page 9
el. +657) in Boring B-5. However, groundwater levels fluctuate over time and may be different at
the time of construction and during the project life. Excavations to remove deep fills from the area
around boring B-3 may encounter groundwater.
• Excavations should be sloped and/or shored to protect worker safety and adjacent properties, per
OSHA and local guidelines and the presence of existing utilities should be thoroughly and carefully
checked prior to digging. Appendix C further discusses excavation recommendations in the
following sections, which can be accessed by clicking hyperlinks: Earthwork, Underground Pipeline,
Excavation De-Watering.
Mass Grading Considerations
• All undocumented fills, debris, grass, roots and other plant materials should be removed from
structural areas of the site. In the new fill areas, the cleaned subgrade should be proofrolled and
evaluated by the engineer with a loaded water truck (4,000 gallon) or equivalent rubber-tired
equipment. Soft or unstable areas should be repaired per the direction of the engineer.
• Prior to the placement of new fill, benching and keying of new fills will be needed. This can be
accomplished by cutting benches parallel to the native slopes, so that new fills can be placed in
roughly horizontal lifts and compacted per the recommendations of Appendix C Earthwork.
• Building 1 will require special attention, as deep, undocumented fill was encountered in Boring B-
3 in the northern portion of the site in the existing parking lot. Additionally, a fill stockpile, and
ravine were encountered there as well that will require remedial grading. Additional test pits could
be performed to determine the extent of the undocumented fill and the composition of the fill
stockpile. Also, this can demonstrate if dewatering would be needed. For the deep backfill (more
than 5 feet) 100% compaction is required to reduce the potential of differential settlement. It is
recommended, that this zone start 5 feet from the edge of building or pavement and extend at a
1:1 slope to the base of fill. In order to achieve this level of compaction, careful attention to moisture
conditioning, lift thickness, and compaction equipment selection will be needed.
• Building 2 calls for relatively deep cutting on the northern portion of the building, in what also
appears to be a berm of undocumented fill that is roughly 15 feet deep (Boring B-4). We believe
this is to be removed during mass grading, however, over-excavation should be done if needed to
fully remove the old fill.
• Building 3 is mostly cut into what appears to be competent native soil. However, removal of dense
trees and filling in of a pond will be needed. This should proceed as previously described.
Spread Foundations
• We anticipate that the new structure(s) may be supported on one of or on a combination of the
following foundation types: primary and structure spread foundations. We assume that after all site
grading is complete as described above, the site native and newly placed engineered fill soil will
generally provide suitable bearing material for spread foundations. The base of excavation for new

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January 19, 2021
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foundations should be evaluated by the engineer, with additional removal of soft or deleterious
material if needed and be otherwise repaired.
• Section 5.2 of this report provides a table outlining the embedment depth, bearing capacity,
settlement and other parameters for foundation design and construction.
On-Grade Construction Considerations
• Given the presence of silt (ML/MH) and clay (CL) material at the surface across the site, we
recommend that the slab on grade be supported by 24 inches of engineered structural fill. The
engineered fill should consist of granular structural fill (material with less than 35% passing the No.
200 Sieve and having a plasticity index less than 10). The fill should extend laterally from the edge
of the new building a distance of 5 feet or more, both at the top and the base of the new fill.
Alternatively, the slabs on grade could be reinforced.
• In new structural areas of the site, all remnants of previous construction, vegetation and/or
deleterious materials should be completely removed to exposed clean subgrade soil. In new fill,
structural, and pavement areas, cleaned subgrade should be proof rolled and evaluated by the
engineer with a loaded water truck (4,000 gallon) or equivalent rubber-tired equipment. In locations
where proof rolling is not feasible, probing, dynamic cone penetration testing or other methods
may be employed. Soft or unstable areas should be repaired per the direction of the engineer. Once
approved, the subgrade soil should be scarified to a depth of 12 inches, moisture conditioned, and
compacted as engineered fill. Improvements in these areas should extend laterally beyond the new
structure limits 2 feet or a distance equal to or greater than the layer thickness, whichever is greater.
This zone should extend vertically from the bearing grade elevation to the base of the fill. The
thicknesses of the layer, settlement estimates, and modulus values are provided in the design tables
in the next section.
• Based on our borings, we anticipate that some over-excavation may result from proof rolling
operations. In areas where unsuitable subgrade conditions are encountered, we recommend an
engineer be called to perform an evaluation of the issue and to propose a resolution. Such
resolutions may include but are not limited to the use of geotextiles, chemical treatments (soil
cement, hydrated lime, etc.) thickened slabs or pavements sections, lime-treated aggregate base,
or others. Pavement sections provided in Section 5.2 are based on approved, compacted in-place
soils being used in the subgrade. If subgrade conditions in the upper 3 feet of pavement areas vary
or are improved, the pavement sections may be modified.
• Appendix C provides additional recommendations for earthwork/on-grade construction in the
following sections: Cast-in-place Concrete, Foundations, Earthwork, Paving, Subgrade Preparation
which can be accessed by clicking the hyperlinks.
Soil Reuse Considerations
• Based on our borings, site soils will generally be unsuitable for reuse as engineered fill in structural
areas, given the moderate to high plasticity of the clay and silt soils, and import or borrow will be
needed. We recommend engineered fill for the structural areas consist of soil with a plasticity index

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less than 10 and that is free of deleterious material. It could also consist of roadway aggregate base
course material or washed durable aggregate such as #57 stone (ASTM C-33). We recommend
engineered fill for the site should be moisture conditioned and compacted to at least 95% of the
maximum dry density in accordance with ASTM D 698 and Appendix C of this report.
• Appendix C provides additional recommendations for soil reuse in the following sections:
EARTHWORK, SUBGRADE PREPARATION which can be accessed by clicking the hyperlinks.
Geotechnical Concrete and Steel Construction Considerations
• Soil/rock may be corrosive to concrete. We recommend using corrosion resistant concrete (e.g.
Type II/V Portland Cement, a fly ash mixture of 25 percent cement replacement, and a water/cement
ratio of 0.45 or less) as directed by the producer, engineer or other qualified party based on their
knowledge of the materials and site conditions. Concrete exposed to freezing weather should be
air entrained. Mix designs should be well-established and reviewed by the project engineers prior
to placement, to verify the design is appropriate to meet the project needs and parameters
provided in this report. Quality control testing should be performed to verify appropriate mixes are
used and are properly handled and placed. Please refer to Appendix C, Cast In-Place Concrete for
more details.
• Soil/rock may be corrosive to un-protected metallic elements such as pipes, poles, rebar, etc. We
recommend the use of coatings and/or cathodic protection for metals in contact with the ground,
as directed by the product manufacturer, engineer or other qualified party based on their
knowledge of the materials to be used and site soil conditions.
Site Storm Water Considerations
• Surface drainage and landscaping design should be carefully planned to protect the new structures
from erosion/undermining, and to maintain the site earthwork and structure subgrades in a
relatively consistent moisture condition. Water should not flow towards or pond near to new
structures, and high water-demand plants should not be planned near to structures. Appendix C
provides additional recommendations for storm water management in the following sections: SITE
GRADING AND DRAINAGE, WATER PROOFING which can be accessed by clicking the hyperlinks.
• We recommend consulting with the landscape designer and civil engineer regarding management
of site storm water and irrigation water, as changes in moisture content below the site after
construction will lead to soil movement and potential distress to the building.

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5.2 Geotechnical Parameters
Based on the findings of our field and laboratory testing, we recommend that design and construction
proceed per industry accepted practices and procedures, as described in Appendix C, General Geotechnical
Design and Construction Considerations (Considerations).
Prepared Subgrade Parameters – (hyperlink to Construction Considerations)
Prepared Subgrade Parameters
Structure Design
Values
Cover
Depth
Bearing Surface a Static
Settlement d
Slab on Grade k=100 pcib
qall=100 psfc
µ = 0.40
N/A 24 inches of reworked/compacted
in-place native sand or select material
extending to approved native
<1 inch
Reinforced Concrete
Slab on Grade
k=70 pcib
qall=100 psfc
µ = 0.35
N/A Reworked/compacted in-place low
plasticity clay and silt (CL/ML)
CH/MH not to be left in upper 2 ft
<1 inch
Conventional Spread
Foundations
qall = 2.5 ksf
µ = 0.35
24
inches
Bearing on approved native or newly
placed engineered fill extending to
approved native soil
<1 inch
a Repairs in bearing surface areas should be structural fill per the recommendation of the Earthwork section of
Appendix C that is moisture conditioned to within 3 percent below to optimum moisture content and compacted
to 95 percent or more of the soil maximum dry density per ASTM D698. Expansive material should not be located
within the upper 3 feet of the soil subgrade.
b Subgrade modulus value “k”, assuming the grade slab is supported by aggregate layer roughly equal to slab
thickness (minimum 4 inches), as required for capillary break
c Can be increased by 1/3 for temporary loading such as seismic and wind, allowable parameters, estimated FS
of 2.5
d Differential settlement is expected to be half to ¾ of total settlement
Pavement Design and Construction Recommendations
• In our experience we recommend that multiple different pavement sections be considered for the
project for economic and performance reasons. For loading docks and trash enclosures we
recommend that thickened reinforced concrete pavement be utilized. For heavily used and ADA
parking spaces, etc., we recommend the use of thinner reinforced concrete pavement. For the main
drives of the parking lot, we recommend a heavy-duty asphalt pavement section, and thinner
sections can be used in the parking field if any. We recommend concrete pavements consist of local
DOT, or otherwise jurisdictionally approved mixes, and that paving cross slopes, curbs, and other
features conform to the applicable local standard specifications and details.
• Depending on the planned changes to site grading, and the availability of clean granular soil,
different pavement sections would be appropriate. These can also be adjusted using treatment
using soil cement. The following sections are provided for native soil subgrade conditions. If
imported fill is used, the section may need to be adjusted. This information assumes that
construction will proceed per the provided Construction Considerations, presented in Appendix C.

Geotechnical Report
Project No. 20-296889.2
January 19, 2021
Page 13
Paving Structural Sections – (hyperlink to Construction Considerations)
Pavement Sections
Roadway Type Subgrade Preparation a Pavement Section b
Parking Area Light Duty (Vehicles) Proof rolled/Compacted Subgrade 3 in. Asphalt/8 in. Aggregate Base
Drive Lanes Heavy Duty (Vehicles) Proof rolled/Compacted Subgrade 4 in. Asphalt /10 in. Aggregate Base
ADA Parking Spaces Proof rolled/Compacted Subgrade 6 in. Concrete/6 in. Aggregate Base
Trash Enclosure/ Dumpster Pad Proof rolled/Compacted Subgrade 8 in. Concrete/6 in. Aggregate Base
a Repairs in proof rolled areas should be structural fill per the recommendation of the APP C Earthwork (hyperlink
to Construction Considerations) that is moisture conditioned to within 3 percent above to optimum moisture
content and compacted to 95 percent or more of the soil maximum dry density per ASTM D698.
b 1 inch of pavement may be reduced if 6-in of lime or cement-treated soil is used with a 500 psi 28-day
compressive strength. Soils with Plasticity Index of 10 or more are generally candidates for lime treatment, other
soils are candidates for cement treatment, if any.

FIGURES
• Site Vicinity Plan
• Boring Location Plan
• Geologic Map

Geotechnical Report
Project No. 20-296889.2
January 19, 2021

`
Source: U.S. Geological Survey, USGS US Topo 7.5-minute map for Charlotte East, North Carolina,
2019: USGS - National Geospatial Technical Operations Center (NGTOC)

FIGURE 1 – SITE VICINITY PLAN
KEY Approximate Site Location
Geotechnical Report
Project No. 20-296889.2
January 19, 2021

Source: Google Earth Pro and undated Concept Plan, prepared by McAdams FIGURE 2 – BORING LOCATION PLAN
KEY Approximate Boring Location

Geotechnical Report
Project No. 20-296889.2
January 19, 2021

Source: Goldsmith, Richard, Milton, D.J., and Horton, J.W., Jr., Geologic map of the Charlotte 1 degree x
2 degrees quadrangle, North Carolina and South Carolina: U.S. Geological Survey, Miscellaneous
Investigations Series Map I-1251-E, scale 1:250,000
FIGURE 3 – GEOLOGIC MAP
KEY Approximate Site Location

APPENDIX A
Boring Logs
SURFACE COVER: General discription with thickness to the inch, ex. Topsoil, Concrete, Asphalt, etc,
FILL: General description with thickness to the 0.5 feet. Ex. Roots, Debris, Processed Materials (Pea Gravel, etc.)
NATIVE GEOLOGIC MATERIAL: Deposit type, 1.Color, 2.moisture, 3.density, 4.SOIL TYPE, other notes - Thickness to 0.5 feet
1. Color - Generalized
Light Brown (usually indicates dry soil, rock, caliche)
Brown (usually indicates moist soil)
Dark Brown (moist to wet soil, organics, clays)
Reddish (or other bright colors) Brown (moist, indicates some soil development/or residual soil)
Greyish Brown (Marine, sub groundwater - not the same as light brown above)
Mottled (brown and gray, indicates groundwater fluctuations)
2. Moisture
dry - only use for wind-blown silts in the desert
damp - soil with little moisture content
moist - near optimum, has some cohesion and stickyness
wet - beyond the plastic limit for clayey soils, and feels wet to the touch for non clays
saturated - Soil below the groundwater table, sampler is wet on outside
3A. Relative Density for Granular Soils 3B. Consistency of Fine-Grained Cohesive Soils
Ring SPT Consistnecy SPT
0-7 0-4 very soft 0-2
7-14 4-10 soft 2-4
14-28 10-30 medium stiff 4-8
28-100 30-50 stiff 8-15
100+ Over 50 very stiff 15-30
hard Over 30
4. Classification
Determine percent Gravel (Material larger than the No. 4 Sieve)
Determine percent fines (Material passing the No. 200 Sieve)
Determine percent sand (Passing the No. 4 and retained on the No. 200 Sieve)
Determine if clayey (make soil moist, if it easily roll into a snake it is clayey)
Coarse Grained Soils (Less than 50% Passing the No. 200 Sieve)
GP SP Mostly sand and gravel, with less than 5 % fines sandy GRAVEL SAND
GP-GM SP-SM Mostly sand and gravel 5-12% fines, non-clayey sandy GRAVEL with silt SAND with Silt
GP-GC SP-SC Mostly sand and gravel 5-12% fines, clayey sandy GRAVEL with clay SAND with clay
GC SC Mostly sand and gravel >12% fines clayey clayey GRAVEL clayey SAND
GM SM Mostly sand and gravel >12% fines non-clayey silty GRAVEL silty SAND
Fine Grained Soils (50% or more passes the No. 200 Sieve)
ML Soft, non clayey SILT with sand
MH Very rare, holds a lot of water, and is pliable with very low strength high plasticity SILT
CL If sandy can be hard when dry, will be stiff/plastic when wet CLAY with sand/silt
CH Hard and resiliant when dry, very strong/sticky when wet (may have sand in it) FAT CLAY
H = Liquid limit over 50%, L - LL under 50%
C = Clay
M = Silt
Samplers
S = Standard split spoon (SPT)
R = Modified ring
Bulk = Excavation spoils
ST = Shelby tube
C = Rock core
BORING LOG KEY - EXPLANATION OF TERMS
Over 2.0
Relative Density
very loose
loose
dense
very dense
medium dense
Undrained Shear Strength, tsf
less than 0.125
0.125 - 0.25
0.25 - 0.50
0.50 - 1.0
1.0 - 2.0
Geotechnical Report
Project No. 20-296889.2 A - 1
1/8/2021
1/8/2021
Depth to Groundwater: 12 feet
Field Technician: W. Johnson
Partner Engineering and Science
8720 Red Oak Blvd, Suite 528
Charlotte, NC 28217
Depth, FT N-Value USCS
0
0.5
1
1.5
2 S 31
2.5
3
3.5
4
4.5
5 S 13
5.5
6
6.5
7 S 11
7.5
8
8.5
9
9.5
10 S 4 CL
10.5
11
11.5
12 ▼
12.5
13
13.5
14
14.5
15 S 5
15.5
16
16.5
17
17.5
18
18.5
19
19.5
20 S 25
Project Number: 20-296889.2
Drill Rig Type: Dietrich D-50
Sampling Equipment: Hollow Stem Auger / Standard 2" Split Spoon Sampler
Boring Number: B-1 Boring Log Page 1 of 2
Location: See Figure 2
Site Address:Toomey Avenue and West Tremont Avenue
Charlotte, North Carolina 28203
Date Completed:
Date Started:
FILL: Dark brown, moist, hard, Silty CLAY, contains brick, wood, and concrete debris
Sample Description
SURFACE COVER: Topsoil (Thickness Varies)
---Stiff below 5 feet
---Wet
NATIVE: Reddish-brown, moist, soft to medium stiff, Silty CLAY
--- Groundwater encountered at 12 feet
--- Reddish-brown to brown, very stiff at 20 feet
8"Borehole Diameter:
Hammer Type: Automatic Hammer
Geotechnical Report
Project No. 20-296889.2 A - 2
1/8/2021
1/8/2021
Depth to Groundwater: 10 feet
Field Technician: W. Johnson
Partner Engineering and Science
8720 Red Oak Blvd, Suite 528
Charlotte, NC 28217
Depth, FT N-Value USCS
20 S 25 CL
20.5
21
21.5
22
22.5
23
23.5
24
24.5
25 S 32
25.5
26
26.5
27
27.5
28
28.5
29
29.5
30 S 29
30.5
31
31.5
32
32.5
33
33.5
34
34.5
35
35.5
36
36.5
37
37.5
38
38.5
39
39.5
40
Project Number: 20-296889.2
Drill Rig Type: Dietrich D-50
Boring Number: B-1 Boring Log Page 1 of 2
Location: See Figure 2
Site Address:Toomey Avenue and West Tremont Avenue
Charlotte, North Carolina 28203
Date Started:
Date Completed:
Sample Description
Reddish-brown to brown, wet, very stiff, Silty CLAY
---Very stiff to hard below 25 feet
Boring terminated at 31.5 feet bgs
Boring backfilled with soil cuttings upon completion
Groundwater encountered at 12 feet (1/8/2021)
Hammer Type: Automatic Hammer
Borehole Diameter: 8"
Hollow Stem Auger / Standard 2" Split Spoon SamplerSampling Equipment:
Geotechnical Report
Project No. 20-296889.2 A - 3
1/8/2021
1/8/2021
Depth to Groundwater: 10 feet
Field Technician: W. Johnson
Partner Engineering and Science
8720 Red Oak Blvd, Suite 528
Charlotte, NC 28217
Depth, FT N-Value USCS
0
0.5
1
1.5
2 S 18 ML
2.5
3
3.5
4
4.5
5 S 13
5.5
6
6.5
7 S 18
7.5
8
8.5
9
9.5
10 S 25 ▼
10.5
11
11.5
12
12.5
13
13.5
14
14.5
15 S 21
15.5
16
16.5
17
17.5
18
18.5
19
19.5
20 S 38 --- Light brown to brown, Hard below 20 feet
--- Groundwater encountered at 10 feet
---Sandy, Stiff at 5 feet
---Very stiff below 7 feet
Borehole Diameter: 8"
NATIVE: Yellow to dark brown, moist, very stiff, Clayey SILT
Sample Description
SURFACE COVER: Topsoil (Thickness Varies)
Boring Number: B-2 Boring Log Page 1 of 2
Location: See Figure 2 Date Started:
Sampling Equipment: Hollow Stem Auger / Standard 2" Split Spoon Sampler
Hammer Type: Automatic Hammer
Drill Rig Type: Dietrich D-50
Site Address:Toomey Avenue and West Tremont Avenue Date Completed:
Charlotte, North Carolina 28203
Project Number: 20-296889.2
Geotechnical Report
Project No. 20-296889.2 A - 4
1/8/2021
1/8/2021
Depth to Groundwater: 10 feet
Field Technician: W. Johnson
Partner Engineering and Science
8720 Red Oak Blvd, Suite 528
Charlotte, NC 28217
Depth, FT N-Value USCS
20 S 38 ML
20.5
21
21.5
22
22.5
23
23.5
24
24.5
25 S 50/6" PWR
25.5
26
26.5
27
27.5
28
28.5
29
29.5
30 S 50/5"
30.5
31
31.5
32
32.5
33
33.5
34
34.5
35
35.5
36
36.5
37
37.5
38
38.5
39
39.5
40
Boring backfilled with soil cuttings upon completion
Groundwater encountered at 10 feet (1/8/2021)
Boring terminated at 30.5 feet bgs
Gray, hard, partially weathered rock (Granite)
Borehole Diameter: 8"
Sample Description
Light brown to brown, wet, hard, Clayey SILT
Boring Number: B-2 Boring Log Page 1 of 2
Location: See Figure 2 Date Started:
Sampling Equipment: Hollow Stem Auger / Standard 2" Split Spoon Sampler
Hammer Type: Automatic Hammer
Drill Rig Type: Dietrich D-50
Site Address:Toomey Avenue and West Tremont Avenue Date Completed:
Charlotte, North Carolina 28203
Project Number: 20-296889.2
Geotechnical Report
Project No. 20-296889.2 A - 5
1/8/2021
1/8/2021
Depth to Groundwater: 10 feet
Field Technician: W. Johnson
Partner Engineering and Science
8720 Red Oak Blvd, Suite 528
Charlotte, NC 28217
Depth, FT N-Value USCS
0
0.5
1
1.5
2 S 77
2.5
3
3.5
4
4.5
5 S 30
5.5
6
6.5
7 S 19
7.5
8
8.5
9
9.5
10 S 13 ▼
10.5 SM
11
11.5
12
12.5
13
13.5
14
14.5
15 S 6
15.5
16
16.5
17
17.5
18
18.5
19
19.5
20 S 16 ---Medium dense at 20 feet
---Loose at 15 feet
sand
--- Groundwater encountered at 10 feet
NATIVE: Dark Brown, wet, medium dense, SAND, some Silt, fine-to-medium grained
---Dark brown to brown very stiff to hard at 5 feet
--- Reddish brown to brown, very stiff, some fine Sand, contains glass and concrete
debris
Borehole Diameter: 8"
FILL: Dark brown, moist, hard, Silty CLAY, contains concrete debris
Sample Description
SURFACE COVER: Topsoil (Thickness Varies)
Boring Number: B-3 Boring Log Page 1 of 2
Location: See Figure 2 Date Started:
Sampling Equipment: Hollow Stem Auger / Standard 2" Split Spoon Sampler
Hammer Type: Automatic Hammer
Drill Rig Type: Dietrich D-50
Site Address:Toomey Avenue and West Tremont Avenue Date Completed:
Charlotte, North Carolina 28203
Project Number: 20-296889.2
Geotechnical Report
Project No. 20-296889.2 A - 6
1/8/2021
1/8/2021
Depth to Groundwater: 10 feet
Field Technician: W. Johnson
Partner Engineering and Science
8720 Red Oak Blvd, Suite 528
Charlotte, NC 28217
Depth, FT N-Value USCS
20 S 16 SM
20.5
21
21.5
22
22.5
23
23.5
24
24.5
25 S 22
25.5
26
26.5
27
27.5
28
28.5
29
29.5
30 S 24 CL
30.5
31
31.5
32
32.5
33
33.5
34
34.5
35
35.5
36
36.5
37
37.5
38
38.5
39
39.5
40
Boring terminated at 31.5 feet bgs
Boring backfilled with soil cuttings upon completion
Groundwater encountered at 10 feet (1/8/2021)
Brown to reddish-brown, wet, very stiff, Silty CLAY, trace fine-grained sand
Borehole Diameter: 8"
Sample Description
Dark Brown, wet, medium dense, SAND, some Silt, fine-to-medium grained sand
Boring Number: B-3 Boring Log Page 1 of 2
Location: See Figure 2 Date Started:
Sampling Equipment: Hollow Stem Auger / Standard 2" Split Spoon Sampler
Hammer Type: Automatic Hammer
Drill Rig Type: Dietrich D-50
Site Address:Toomey Avenue and West Tremont Avenue Date Completed:
Charlotte, North Carolina 28203
Project Number: 20-296889.2
Geotechnical Report
Project No. 20-296889.2 A - 7
1/8/2021
1/8/2021
Depth to Groundwater: 24 feet
Field Technician: W. Johnson
Partner Engineering and Science
8720 Red Oak Blvd, Suite 528
Charlotte, NC 28217
Depth, FT N-Value USCS
0
0.5
1
1.5
2 S 7
2.5
3
3.5
4
4.5
5 S 5
5.5
6
6.5
7 S 4
7.5
8
8.5
9
9.5
10 S 3
10.5
11
11.5
12
12.5
13
13.5
14
14.5
15 S 27 ML
15.5
16
16.5
17
17.5
18
18.5
19
19.5
20 S 41 --- Hard at 20 feet
NATIVE: Brown to reddish brown, moist, very stiff, Clayey SILT
--- Brown to reddish-brown, soft, contains gravel at 10 feet
---Soft to medium stiff at 7 feet
Borehole Diameter: 8"
Sample Description
SURFACE COVER: Topsoil (Thickness Varies)
FILL: Brown, moist, medium stiff, Clayey SILT, some Sand, contains organics
Boring Number: B-4 Boring Log Page 1 of 2
Location: See Figure 2 Date Started:
Sampling Equipment: Hollow Stem Auger / Standard 2" Split Spoon Sampler
Hammer Type: Automatic Hammer
Drill Rig Type: Dietrich D-50
Site Address:Toomey Avenue and West Tremont Avenue Date Completed:
Charlotte, North Carolina 28203
Project Number: 20-296889.2
Geotechnical Report
Project No. 20-296889.2 A - 8
1/8/2021
1/8/2021
Depth to Groundwater: 24 feet
Field Technician: W. Johnson
Partner Engineering and Science
8720 Red Oak Blvd, Suite 528
Charlotte, NC 28217
Depth, FT N-Value USCS
20 S 41 ML
20.5
21
21.5
22
22.5
23
23.5
24 ▼
24.5
25 S 50/5" PWR
25.5
26
26.5
27
27.5
28
28.5
29
29.5
30 S 50/5"
30.5
31
31.5
32
32.5
33
33.5
34
34.5
35
35.5
36
36.5
37
37.5
38
38.5
39
39.5
40
Boring backfilled with soil cutting upon completion
Groundwater encountered at 24 feet (1/8/2021)
Boring terminated at 30.5 feet bgs
Gray, hard, partially weathered rock (Granite)
Borehole Diameter: 8"
--- Groundwater encountered at 24 feet
Sample Description
Brown to reddish brown, moist, hard, Clayey SILT
Boring Number: B-4 Boring Log Page 1 of 2
Location: See Figure 2 Date Started:
Sampling Equipment: Hollow Stem Auger / Standard 2" Split Spoon Sampler
Hammer Type: Automatic Hammer
Drill Rig Type: Dietrich D-50
Site Address:Toomey Avenue and West Tremont Avenue Date Completed:
Charlotte, North Carolina 28203
Project Number: 20-296889.2
Geotechnical Report
Project No. 20-296889.2 A - 9
1/8/2021
1/8/2021
Depth to Groundwater: 10 feet
Field Technician: W. Johnson
Partner Engineering and Science
8720 Red Oak Blvd, Suite 528
Charlotte, NC 28217
Depth, FT N-Value USCS
0
0.5
1 CL
1.5
2 S 9
2.5
3
3.5
4
4.5
5 S 19
5.5
6
6.5
7 S 54 ML
7.5
8
8.5
9
9.5
10 S 47 ▼
10.5
11
11.5
12
12.5
13
13.5
14
14.5
15 S 50/4" PWR
15.5
16
16.5
17
17.5
18
18.5
19
19.5
20 S 50/3"
Gray, hard, partially weathered rock (Granite)
--- Groundwater encountered at 10 feet
---Very stiff at 5 feet
Light brown to gray, moist, hard, Sandy SILT
Sample Description
SURFACE COVER: Topsoil (Thickness Varies)
NATIVE: Brown to reddish-brown, moist, stiff, Silty CLAY
Borehole Diameter: 8"
Site Address:Toomey Avenue and West Tremont Avenue Date Completed:
Charlotte, North Carolina 28203
Project Number: 20-296889.2
Boring Number: B-5 Boring Log Page 1 of 2
Location: See Figure 2 Date Started:
Hammer Type: Automatic Hammer
Drill Rig Type: Dietrich D-50
Sampling Equipment: Hollow Stem Auger / Standard 2" Split Spoon Sampler
Geotechnical Report
Project No. 20-296889.2 A - 10
1/8/2021
1/8/2021
Depth to Groundwater: 10 feet
Field Technician: W. Johnson
Partner Engineering and Science
8720 Red Oak Blvd, Suite 528
Charlotte, NC 28217
Depth, FT N-Value USCS
20 S 50/3" PWR
20.5
21
21.5
22
22.5
23
23.5
24
24.5
25
25.5
26
26.5
27
27.5
28
28.5
29
29.5
30
30.5
31
31.5
32
32.5
33
33.5
34
34.5
35
35.5
36
36.5
37
37.5
38
38.5
39
39.5
40
Borehole Diameter: 8"
Sample Description
Gray, hard, partially weathered rock (Granite)
Boring terminated at 20.5 feet bgs
Boring backfilled with soil cutting upon completion
Groundwater encountered at 10 feet (1/8/2021)
Boring Number: B-5 Boring Log Page 1 of 2
Location: See Figure 2 Date Started:
Sampling Equipment: Hollow Stem Auger / Standard 2" Split Spoon Sampler
Hammer Type: Automatic Hammer
Drill Rig Type: Dietrich D-50
Site Address:Toomey Avenue and West Tremont Avenue Date Completed:
Charlotte, North Carolina 28203
Project Number: 20-296889.2
Geotechnical Report
Project No. 20-296889.2 A - 11
1/7/2021
1/7/2021
Depth to Groundwater: 14 feet
Field Technician: W. Johnson
Partner Engineering and Science
8720 Red Oak Blvd, Suite 528
Charlotte, NC 28217
Depth, FT N-Value USCS
0
0.5
1 CL
1.5
2 S 6
2.5
3
3.5
4
4.5
5 S 12
5.5
6
6.5
7 S 10 ML
7.5
8
8.5
9
9.5
10 S 7
10.5
11
11.5
12
12.5
13
13.5
14 ▼
14.5
15 S 7
15.5
16
16.5
17
17.5
18
18.5
19
19.5
20 S 18 ---Very stiff below 20 feet
Groundwater encountered at 14 feet
---Medium stiff below 10 feet
---Stiff, some fine-grained sand
Brown to reddish-brown, moist, stiff, Clayey SILT
Borehole Diameter: 8"
Sample Description
SURFACE COVER: Topsoil (Thickness Varies)
NATIVE: Brown to reddish-brown, moist, medium stiff, Silty CLAY
Boring Number: B-6 Boring Log Page 1 of 2
Location: See Figure 2 Date Started:
Sampling Equipment: Hollow Stem Auger / Standard 2" Split Spoon Sampler
Hammer Type: Automatic Hammer
Drill Rig Type: Dietrich D-50
Site Address:Toomey Avenue and West Tremont Avenue Date Completed:
Charlotte, North Carolina 28203
Project Number: 20-296889.2
Geotechnical Report
Project No. 20-296889.2 A - 12
1/7/2021
1/7/2021
Depth to Groundwater: 14 feet
Field Technician: W. Johnson
Partner Engineering and Science
8720 Red Oak Blvd, Suite 528
Charlotte, NC 28217
Depth, FT N-Value USCS
20 S 18 ML
20.5
21
21.5
22
22.5
23
23.5
24
24.5
25 S 23
25.5
26
26.5
27
27.5
28
28.5
29
29.5
30 S 46
30.5
31
31.5
32
32.5
33
33.5
34
34.5
35
35.5
36
36.5
37
37.5
38
38.5
39
39.5
40
Boring terminated at 31.5 feet bgs
Boring backfilled with soil cuttings upon completion
Groundwater encountered at 14 feet (1/7/2021)
--- Hard at 30 feet
Sample Description
Light brown to brown, wet, very stiff, Sandy SILT
8"Borehole Diameter:
Automatic HammerHammer Type:
Hollow Stem Auger / Standard 2" Split Spoon SamplerSampling Equipment:
Boring Number: B-6 Boring Log Page 1 of 2
Location: See Figure 2 Date Started:
Drill Rig Type: Dietrich D-50
Site Address:Toomey Avenue and West Tremont Avenue Date Completed:
Charlotte, North Carolina 28203
Project Number: 20-296889.2
Geotechnical Report
Project No. 20-296889.2 A - 13
1/7/2021
1/7/2021
Depth to Groundwater: 14 feet
Field Technician: W. Johnson
Partner Engineering and Science
8720 Red Oak Blvd, Suite 528
Charlotte, NC 28217
Depth, FT N-Value USCS
0
0.5
1 ML
1.5
2 S 11
2.5
3
3.5
4
4.5
5 S 8
5.5
6
6.5
7 S 9
7.5
8
8.5
9
9.5
10 S 8
10.5
11
11.5
12
12.5
13
13.5
14 ▼
14.5
15 S 4
15.5
16
16.5
17
17.5
18
18.5
19
19.5
20 S 5 ---Medium stiff below 20 feet
Groundwater encountered at 14 feet
---Light brown to brown, wet, soft to medium stiff at 15 feet
---Medium stiff to stiff at 10 feet
---medium stiff to stiff at 5 feet
Brown, moist, stiff, Clayey SILT
Borehole Diameter: 8"
Sample Description
SURFACE COVER: Topsoil (Thickness Varies)
NATIVE: Brown, moist, stiff, Clayey SILT
Boring Number: B-7 Boring Log Page 1 of 2
Location: See Figure 2 Date Started:
Sampling Equipment: Hollow Stem Auger / Standard 2" Split Spoon Sampler
Hammer Type: Automatic Hammer
Drill Rig Type: Dietrich D-50
Site Address:Toomey Avenue and West Tremont Avenue Date Completed:
Charlotte, North Carolina 28203
Project Number: 20-296889.2
Geotechnical Report
Project No. 20-296889.2 A - 14
1/7/2021
1/7/2021
Depth to Groundwater: 14 feet
Field Technician: W. Johnson
Partner Engineering and Science
8720 Red Oak Blvd, Suite 528
Charlotte, NC 28217
Depth, FT N-Value USCS
20 S 5 ML
20.5
21
21.5
22
22.5
23
23.5
24
24.5
25 S 9
25.5
26
26.5
27
27.5
28
28.5
29
29.5
30 S 12
30.5
31
31.5
32
32.5
33
33.5
34
34.5
35
35.5
36
36.5
37
37.5
38
38.5
39
39.5
40
Boring terminated at 31.5 feet bgs
Boring backfilled with soil cuttings upon completion
Groundwater encountered at 14 feet (1/7/2021)
---Stiff at 30 feet
---Trace fine-grained sand at 25 feet
Borehole Diameter: 8"
Sample Description
Brown, moist, medium stiff, Clayey SILT
Boring Number: B-7 Boring Log Page 1 of 2
Location: See Figure 2 Date Started:
Sampling Equipment: Hollow Stem Auger / Standard 2" Split Spoon Sampler
Hammer Type: Automatic Hammer
Drill Rig Type: Dietrich D-50
Site Address:Toomey Avenue and West Tremont Avenue Date Completed:
Charlotte, North Carolina 28203
Project Number: 20-296889.2
Geotechnical Report
Project No. 20-296889.2 A - 15
1/7/2021
1/7/2021
Depth to Groundwater: 14 feet
Field Technician: W. Johnson
Partner Engineering and Science
8720 Red Oak Blvd, Suite 528
Charlotte, NC 28217
Depth, FT N-Value USCS
0
0.5
1 ML
1.5
2 S 15
2.5
3
3.5
4
4.5
5 S 10
5.5
6
6.5
7 S 11
7.5
8
8.5
9
9.5
10 S 8
10.5
11
11.5
12
12.5
13
13.5
14 ▼
14.5
15 S 9
15.5
16
16.5
17
17.5
18
18.5
19
19.5
20 S 13
Groundwater encountered at 14 feet
---Brown, medium stiff to stiff below 10 feet
---Stiff below 5 feet
--- Light brown at 7 feet
Borehole Diameter: 8"
Sample Description
SURFACE COVER: Topsoil (Thickness Varies)
NATIVE: Reddish-brown, moist, stiff to very stiff, Clayey SILT
Boring Number: B-8 Boring Log Page 1 of 2
Location: See Figure 2 Date Started:
Sampling Equipment: Hollow Stem Auger / Standard 2" Split Spoon Sampler
Hammer Type: Automatic Hammer
Drill Rig Type: Dietrich D-50
Site Address:Toomey Avenue and West Tremont Avenue Date Completed:
Charlotte, North Carolina 28203
Project Number: 20-296889.2
Geotechnical Report
Project No. 20-296889.2 A - 16
1/7/2021
1/7/2021
Depth to Groundwater: 14 feet
Field Technician: W. Johnson
Partner Engineering and Science
8720 Red Oak Blvd, Suite 528
Charlotte, NC 28217
Depth, FT N-Value USCS
20 S 13 ML
20.5
21
21.5
22
22.5
23
23.5
24
24.5
25 S 16
25.5
26
26.5
27
27.5
28
28.5
29
29.5
30 S 9
30.5
31
31.5
32
32.5
33
33.5
34
34.5
35
35.5
36
36.5
37
37.5
38
38.5
39
39.5
40
Boring terminated at 31.5 feet bgs
Boring backfilled with soil cuttings upon completion
Groundwater encountered at 14 feet (1/7/2021)
---Stiff at 30 feet
---Very stiff, trace fine-grained sand at 25 feet
Borehole Diameter: 8"
Sample Description
Reddish-brown, moist, stiff, Clayey SILT
Boring Number: B-8 Boring Log Page 1 of 2
Location: See Figure 2 Date Started:
Sampling Equipment: Hollow Stem Auger / Standard 2" Split Spoon Sampler
Hammer Type: Automatic Hammer
Drill Rig Type: Dietrich D-50
Site Address:Toomey Avenue and West Tremont Avenue Date Completed:
Charlotte, North Carolina 28203
Project Number: 20-296889.2
Geotechnical Report
Project No. 20-296889.2 A - 17
1/7/2021
1/7/2021
Depth to Groundwater: 14 feet
Field Technician: W. Johnson
Partner Engineering and Science
8720 Red Oak Blvd, Suite 528
Charlotte, NC 28217
Depth, FT N-Value USCS
0
0.5
1 ML
1.5
2 S 9
2.5
3
3.5
4
4.5
5 S 7 MH
5.5
6
6.5
7 S 8
7.5
8
8.5
9
9.5
10 S 8
10.5
11
11.5
12
12.5
13
13.5
14 ▼
14.5
15 S 17
15.5
16
16.5
17
17.5
18
18.5
19
19.5
20 S 16
Groundwater encountered at 14 feet
---Wet, very stiff below 15 feet
---Light brown at 10 feet
Reddish-brown, moist, medium stiff, Clayey SILT
---Medium stiff to stiff below 7 feet
Borehole Diameter: 8"
Sample Description
SURFACE COVER: Topsoil (Thickness Varies)
NATIVE: Reddish-brown, moist, stiff, Clayey SILT
Boring Number: B-9 Boring Log Page 1 of 2
Location: See Figure 2 Date Started:
Sampling Equipment: Hollow Stem Auger / Standard 2" Split Spoon Sampler
Hammer Type: Automatic Hammer
Drill Rig Type: Dietrich D-50
Site Address:Toomey Avenue and West Tremont Avenue Date Completed:
Charlotte, North Carolina 28203
Project Number: 20-296889.2
Geotechnical Report
Project No. 20-296889.2 A - 18
1/7/2021
1/7/2021
Depth to Groundwater: 14 feet
Field Technician: W. Johnson
Partner Engineering and Science
8720 Red Oak Blvd, Suite 528
Charlotte, NC 28217
Depth, FT N-Value USCS
20 S 16 ML
20.5
21
21.5
22
22.5
23
23.5
24
24.5
25 S 37
25.5
26
26.5
27
27.5
28
28.5
29
29.5
30 S 50/4" PWR
30.5
31
31.5
32
32.5
33
33.5
34
34.5
35
35.5
36
36.5
37
37.5
38
38.5
39
39.5
40
Boring backfilled with soil cuttings upon completion
Groundwater encountered at 14 feet (1/7/2021)
Gray, hard, partially weathered rock (Granite)
Boring terminated at 30.5 feet bgs
---Hard below 25 feet
Sample Description
Reddish-brown, moist, very stiff, Clayey SILT
Drill Rig Type: Dietrich D-50
Sampling Equipment: Hollow Stem Auger / Standard 2" Split Spoon Sampler
Hammer Type: Automatic Hammer
Borehole Diameter: 8"
Site Address:Toomey Avenue and West Tremont Avenue Date Completed:
Charlotte, North Carolina 28203
Project Number: 20-296889.2
Boring Number: B-9 Boring Log Page 1 of 2
Location: See Figure 2 Date Started:
Geotechnical Report
Project No. 20-296889.2 A - 19
1/7/2021
1/7/2021
Depth to Groundwater: 14 feet
Field Technician: W. Johnson
Partner Engineering and Science
8720 Red Oak Blvd, Suite 528
Charlotte, NC 28217
Depth, FT N-Value USCS
0
0.5
1 CL
1.5
2 S 13
2.5
3
3.5
4
4.5
5 S 9
5.5
6
6.5
7 S 14
7.5
8
8.5
9
9.5
10 S 12 ML
10.5
11
11.5
12
12.5
13
13.5
14 ▼
14.5
15 S 31
15.5
16
16.5
17
17.5
18
18.5
19
19.5
20 S 22 --- Very stiff below 20 feet
Groundwater encountered at 14 feet
---Wet, hard below 15 feet
Brown, moist, stiff, Clayey SILT, some fine-grained sand
---Brownish-gray
--- Light brown, some fine-grained sand at 7 feet
Borehole Diameter: 8"
Sample Description
SURFACE COVER: Topsoil (Thickness Varies)
NATIVE: Reddish-brown, moist, stiff, Silty CLAY, contains gravel
Boring Number: B-10 Boring Log Page 1 of 2
Location: See Figure 2 Date Started:
Sampling Equipment: Hollow Stem Auger / Standard 2" Split Spoon Sampler
Hammer Type: Automatic Hammer
Drill Rig Type: Dietrich D-50
Site Address:Toomey Avenue and West Tremont Avenue Date Completed:
Charlotte, North Carolina 28203
Project Number: 20-296889.2
Geotechnical Report
Project No. 20-296889.2 A - 20
1/7/2021
1/7/2021
Depth to Groundwater: 14 feet
Field Technician: W. Johnson
Partner Engineering and Science
8720 Red Oak Blvd, Suite 528
Charlotte, NC 28217
Depth, FT N-Value USCS
20 S 22 ML
20.5
21
21.5
22
22.5
23
23.5
24
24.5
25 S 43
25.5
26
26.5
27
27.5
28
28.5
29
29.5
30 S 50/5" PWR
30.5
31
31.5
32
32.5
33
33.5
34
34.5
35
35.5
36
36.5
37
37.5
38
38.5
39
39.5
40
Boring backfilled with soil cuttings upon completion
Groundwater encountered at 14 feet (1/7/2021)
Gray, hard, partially weathered rock (Granite)
Boring terminated at 30.5 feet bgs
---Hard, sandy below 25 feet
Borehole Diameter: 8"
Sample Description
Brown, moist, stiff, Clayey SILT, some fine-to-medium grained sand
Boring Number: B-10 Boring Log Page 1 of 2
Location: See Figure 2 Date Started:
Sampling Equipment: Hollow Stem Auger / Standard 2" Split Spoon Sampler
Hammer Type: Automatic Hammer
Drill Rig Type: Dietrich D-50
Site Address:Toomey Avenue and West Tremont Avenue Date Completed:
Charlotte, North Carolina 28203
Project Number: 20-296889.2
Geotechnical Report
Project No. 20-296889.2 A - 21

APPENDIX B
Lab Data
Geotechnical Report
Project No. 20-296889.2
January 19, 2021
Page B-i

Plasticity Index Data
Symbol Boring Depth, ft Natural Moisture
Content (%)
Plasticity Index Plastic Limit Liquid Limit
□ B-7 2 20.0 14 27 41
■ B-9 5 45.7 31 41 72

Group and USCS Symbols Soil Descriptions
GROUP 1 – ML, SM, GM, OL* SILTS, SANDS, AND GRAVELS WITH NO TO MEDIUM PLASTICITY
GROUP 1.5 – ML-CL, SM-SC, GM-GC, OL* CLAYS, SILTS, SANDS, AND GRAVELS WITH LOW PLASTICITY
GROUP 2 – CL, SC, GC, OL* CLAYS, SANDS, AND GRAVELS WITH LOW TO MEDIUM PLASTICITY
GROUP 3 – MH, SM, GM, OH* SILTS, SANDS, AND GRAVELS WITH NO TO HIGH PLASTICITY
GROUP 4 – CH, SC, GC, OH* CLAYS, SANDS, AND GRAVELS WITH HIGH PLASTICITY
*Or combinations of any within the same group (example ML-SM or CL-SC)

0
10
20
30
40
50
60
0 10 20 30 40 50 60 70 80 90 100Plasticity Index, PILiquid Limit, %
GROUP 3
GROUP 4
GROUP 2
GROUP 1.5
GROUP 1
U-Line
A-Line
Geotechnical Report
Project No. 20-296889.2
January 19, 2021
Page B-ii

Index Test Data

Boring Depth, ft Plasticity
Index
Plastic
Limit
Liquid
Limit
Moisture
Content (%)
%Passing
The No.
200 Sieve
B-2 2 - - - 12.4 -
B-2 5 - - - 19.4 31.7
B-3 2 - - - 21 -
B-3 5 - - - 22.2 -
B-3 7 - - - 19.6 -
B-4 2 - - - 14.7 -
B-4 5 - - - 19.2 -
B-5 2 - - - 30.7 -
B-5 7 - - - 13.7 36.1
B-5 20 - - - 10.4 -
B-6 2 - - - 44.9 -
B-6 5 - - - 27.4 -
B-7 2 14 27 41 20.0 -
B-7 7 - - - 34.1 -
B-8 2 - - - 17.5 -
B-8 5 - - - 30.7 -
B-9 2 - - - 26 -
B-9 5 31 41 72 45.7 -
B-9 7 - - - 41.5 -
B-10 2 - - - 17.2 -
B-10 15 - - - 36.1 -

APPENDIX C
General Geotechnical Design and Construction Considerations
Subgrade Preparation
Earthwork – Structural Fill/Excavations
Underground Pipeline Installation – Structural Backfill
Cast-in-Place Concrete
Foundations
Laterally Loaded Structures
Excavations and Dewatering
Waterproofing and Drainage
Chemical Treatment of Soils
Paving
Site Grading and Drainage

Geotechnical Report
Project No. 20-296889.2
January 19, 2021
Page C-i

SUBGRADE PREPARATION
1. In general, construction should proceed per the project specifications and contract documents, as
well as governing jurisdictional guidelines for the project site, including but not limited to the
applicable State Department of Transportation, City and/or County, Army Corps of Engineers,
Federal Aviation, Occupational Safety and Health Administration (OSHA), and any other governing
standard details and specifications. In areas where multiple standards are applicable the more
stringent should be considered. Work should be performed by qualified, licensed contractors with
experience in the specific type of work in the area of the site.
2. Subgrade preparation in this section is considered to apply to the initial modifications to existing
site conditions to prepare for new planned construction.
3. Prior to the start of subgrade preparation, a detailed conflict study including as-builts, utility
locating, and potholing should be conducted. Existing features that are to be demolished should
also be identified and the geotechnical study should be referenced to determine the need for
subgrade preparation, such as over-excavation, scarification and compaction, moisture
conditioning, and/or other activities below planned new structural fills, slabs on grade, pavements,
foundations, and other structures.
4. The site conflicts, planned demolitions, and subgrade preparation requirements should be
discussed in a pre-construction meeting with the pertinent parties, including the geotechnical
engineer, inspector, contractors, testing laboratory, surveyor, and others.
5. In the event of preparations that will require work near to existing structures to remain in-place,
protection of the existing structures should be considered. This also includes a geotechnical review
of excavations near to existing structures and utilities and other concerns discussed in General
Geotechnical Design and Construction Considerations, EARTHWORK and UNDERGROUND
PIPELINE INSTALLATION.
6. Features to be demolished should be completely removed and disposed of per jurisdictional
requirements and/or other conditions set forth as a part of the project. Resulting excavations or
voids should be backfilled per the recommendations in the General Geotechnical Design and
Construction Considerations, EARTHWORK section.
7. Vegetation, roots, soils containing organic materials, debris and/or other deleterious materials on
the site should be removed from structural areas and should be disposed of as above. Replacement
of such materials should be in accordance with the recommendations in the General Geotechnical
Design and Construction Considerations, EARTHWORK section
8. Subgrade preparation required by the geotechnical report may also call for as over-excavation,
scarification and compaction, moisture conditioning, and/or other activities below planned
structural fills, slabs on grade, pavements, foundations, and other structures. These requirements
should be provided within the geotechnical report. The execution of this work should be observed
by the geotechnical engineering representative or inspector for the site. Testing of the subgrade
preparation should be performed per the recommendations in the General Geotechnical Design
and Construction Considerations, EARTHWORK section.

Geotechnical Report
Project No. 20-296889.2
January 19, 2021
Page C-ii

9. Subgrade Preparation cannot be completed on frozen ground or on ground that is not at a proper
moisture condition. Wet subgrades may be dried under favorable weather if they are disked and/or
actively worked during hot, dry, weather, when exposed to wind and sunlight. Frozen ground or
wet material can be removed and replaced with suitable material. Dry material can be pre-soaked
or can have water added and worked in with appropriate equipment. The soil conditions should be
monitored by the geotechnical engineer prior to compaction. Following this type of work, approved
subgrades should be protected by direction of surface water, covering, or other methods, otherwise,
re-work may be needed.

Geotechnical Report
Project No. 20-296889.2
January 19, 2021
Page C-iii

EARTHWORK – STRUCTURAL FILL
1. In general, construction should proceed per the governing jurisdictional guidelines for the project
site, including but not limited to the applicable State Department of Transportation, City and/or
County, Army Corps of Engineers, Federal Aviation, Occupational Safety and Health Administration
(OSHA), and any other governing standard details and specifications. In areas where multiple
standards are applicable the more stringent should be considered. Work should be performed by
qualified, licensed contractors with experience in the specific type of work in the area of the site.
2. Earthwork in this section is considered to apply to the re-shaping and grading of soil, rock, and
aggregate materials for the purpose of supporting man-made structures. Where earthwork is
needed to raise the elevation of the site for the purpose of supporting structures or forming slopes,
this is referred to as the placement of structural fill. Where lowering of site elevations is needed
prior to the installation of new structures, this is referred to as earthwork excavations.
3. Prior to the start of earthwork operations, the geotechnical study should be referenced to
determine the need for subgrade preparation, such as over-excavation or scarification and
compaction of unsuitable soils below planned structural fills, slabs on grade, pavements,
foundations, and other structures. These required preparations should be discussed in a pre-
construction meeting with the pertinent parties, including the geotechnical engineer, inspector,
contractors, testing laboratory, surveyor, and others. The preparations should be observed by the
inspector or geotechnical engineer representative, and following such subgrade preparation, the
geotechnical engineer should observe the prepared subgrade to approve it for the placement of
earthwork fills or new structures.
4. Structural fill materials should be relatively free of organic materials, man-made debris,
environmentally hazardous materials, and brittle, non-durable aggregate, frozen soil, soil clods or
rocks and/or any other materials that can break down and degrade over time.
5. In deeper structural fill zones, expansive soils (greater than 1.5 percent swell at 100 pounds per
square foot surcharge) and rock fills (fills containing particles larger than 4 inches and/or containing
more than 35 percent gravel larger than ¾-inch diameter or more than 50 percent gravel) may be
used with the approval and guidance of the geotechnical report or geotechnical engineer. This may
require the placement of geotextiles or other added costs and/or conditions. These conditions may
also apply to corrosive soils (less than 2,000 ohm-cm resistivity, more than 50 ppm chloride content,
more than 0.1 percent sulfates)
6. For structural fill zones that are closer in depth below planed structures, low expansive materials,
and materials with smaller particle size are generally recommended, as directed by the geotechnical
report (see criteria above in 5). This may also apply to corrosive soils.
7. For structural fill materials, in general the compaction equipment should be appropriate for the
thickness of the loose lift being placed, and the thickness of the loose lift being placed should be
at least two times the maximum particle size incorporated in the fill.
8. Fill lift thickness (including bedding) should generally be proportioned to achieve 95 percent or
more of a standard proctor (ASTM D689) maximum dry density (MDD) or 90 percent or more of a
modified proctor (ASTM D1557) MDD, depending on the state practices. For subgrades below

Geotechnical Report
Project No. 20-296889.2
January 19, 2021
Page C-iv

roadways, the general requirement for soil compaction is usually increased to 100 percent or more
of the standard proctor MDD and 95 percent or more of the modified proctor MDD.
9. Soil compaction should be performed at a moisture content generally near optimum moisture
content determined by either standard or modified proctor, and ideally within 3 percent below to
1 percent over the optimum for a standard proctor, and from 2 percent below to 2 percent above
optimum for a modified proctor.
10. In some instances, fill areas are difficult to access. In such cases a low-strength soil-cement slurry
can be used in the place of compacted fill soil. In general, such fills should be rated to have a 28-
day strength of 75 to 125 psi, which in some areas is referred to as a “1-sack” slurry. It should be
noted that these materials are wet during placement and require a period of 2 days (24 hours) to
cure before additional fill can be placed above them. Testing of this material can be done using
concrete cylinder compression strength testing equipment, but care is needed in removing the test
specimens from the molds. Field testing using the ball method and spread or flow testing is also
acceptable.
11. For fills to be placed on slopes, benching of fill lifts is recommended, which may require cutting
into existing slopes to create a bench parallel to the slope where soil can be placed in a relatively
horizontal orientation. For the construction of slopes, the slopes should be over-built and cut back
to grade, as the material in the outer portion of the slope may not be well compacted.
12. For subgrade below roadways, runways, railways or other areas to receive dynamic loading, a proof
roll of the finished, compacted subgrade should be performed by the geotechnical engineer or
inspector prior to the placement of structural aggregate, asphalt or concrete. Proof rolling consists
of observing the performance of the subgrade under heavy-loaded equipment, such as full, 4,000
Gallon water truck, loaded tandem-axel dump truck or similar. Areas that exhibit instability during
proof roll should be marked for additional work prior to approval of the subgrade for the next stage
of construction.
13. Quality control testing should be provided on earthwork. Proctor testing should be performed on
each soil type, and one-point field proctors should be used to verify the soil types during
compaction testing. If compaction testing is performed with a nuclear density gauge, it should be
periodically correlated with a sand cone test for each soil type. Density testing should be performed
per project specifications and or jurisdictional requirements, but not less than once per 12 inches
elevation of any fill area, with additional tests per 12-inch fill area for each additional 7,500 square-
foot section or portion thereof.
14. For earthwork excavations, OSHA guidelines should be referenced for sloping and shoring.
Excavations over a depth of 20 feet require a shoring design. In the event excavations are planned
near to existing structures, the geotechnical engineer should be consulted to evaluate whether such
excavation will call for shoring or underpinning the adjacent structure. Pre-construction and post-
construction condition surveys and vibration monitoring might also be helpful to evaluate any
potential damage to surrounding structures.
15. Excavations into rock, partially weathered rock, cemented soils, boulders and cobbles, and other
hard soil or “hard-pan” materials, may result in slower excavation rates, larger equipment with

Geotechnical Report
Project No. 20-296889.2
January 19, 2021
Page C-v

specialized digging tools, and even blasting. It is also not unusual in these situations for screening
and or crushing of rock to be called for. Blasting, hard excavating, and material processing
equipment have special safety concerns and are more costly than the use of soil excavation
equipment. Additionally, this type of excavation, especially blasting, is known to cause vibrations
that should be monitored at nearby structures. As above, a pre-blast and post-blast conditions
assessment might also be warranted.

Geotechnical Report
Project No. 20-296889.2
January 19, 2021
Page C-vi

UNDERGROUND PIPELINE – STRUCTURAL BACKFILL
1. In general, construction should proceed per the governing jurisdictional guidelines for the project
site, including but not limited to the applicable State Department of Transportation, the State
Department of Environmental Quality, the US Environmental Protection Agency, City and/or County
Public Works, Occupational Safety and Health Administration (OSHA), Private Utility Companies,
and any other governing standard details and specifications. In areas where multiple standards are
applicable the more stringent should be considered, and in some cases, work may take place to
multiple different standards. Work should be performed by qualified, licensed contractors with
experience in the specific type of work in the area of the site.
2. Underground pipeline in this section is considered to apply to the installation of underground
conduits for water, storm water, irrigation water, sewage, electricity, telecommunications, gas, etc.
Structural backfill refers to the activity of restoring the grade or establishing a new grade in the
area where excavations were needed for the underground pipeline installation.
3. Prior to the start of underground pipeline installation, a detailed conflict study including as-builts,
utility locating, and potholing should be conducted. The geotechnical study should be referenced
to determine subsurface conditions such as caving soils, unsuitable soils, shallow groundwater,
shallow rock and others. In addition, the utility company responsible for the line also will have
requirements for pipe bedding and support as well as other special requirements. Also, if the
underground pipeline transverses other properties, rights-of-way, and/or easements etc. (for roads,
waterways, dams, railways, other utility corridors, etc.) those owners may have additional
requirements for construction.
4. The required preparations above should be discussed in a pre-construction meeting with the
pertinent parties, including the geotechnical engineer, inspector, contractors, testing laboratory,
surveyor, and other stake holders.
5. For pipeline excavations, OSHA guidelines should be referenced for sloping and shoring.
Excavations over a depth of 20 feet require a shoring design. In the event excavations are planned
near to existing structures or pipelines, the geotechnical engineer should be consulted to evaluate
whether such excavation will call for shoring or supporting the adjacent structure or pipeline. A pre-
construction and post-construction condition survey and vibration monitoring might also be
helpful to evaluate any potential damage to surrounding structures.
6. Excavations into rock, partially weathered rock, cemented soils, boulders and cobbles, and other
hard soil or “hard-pan” materials, may result in slower excavation rates, larger equipment with
specialized digging tools, and even blasting. It is also not unusual in these situations for screening
and or crushing of rock to be called for. Blasting, hard excavating and material processing
equipment have special safety concerns and are more costly than the use soil excavation
equipment. Additionally, this type of excavation, especially blasting, is known to cause vibrations
that should be monitored at nearby structures. As above, a pre-blast and post-blast conditions
assessment might also be warranted.
7. Bedding material requirements vary between utility companies and might depend of the type of
pipe material and availability of different types of aggregates in different locations. In general,

Geotechnical Report
Project No. 20-296889.2
January 19, 2021
Page C-vii

bedding refers to the material that supports the bottom of the pipe and extends to 1 foot above
the top of the pipe. In general, the use of aggregate base for larger diameter pipes (6-inch diameter
or more) is recommended lacking a jurisdictionally specified bedding material. Gas lines and smaller
diameter lines are often backfilled with fine aggregate meeting the ASTM requirements for concrete
sand. In all cases bedding with less than 2,000 ohm-cm resistivity, more than 50 ppm chloride
content or more than 0.1 percent sulfates should not be used.
8. Structural backfill materials above the bedding should be relatively free of organic materials, man-
made debris, environmentally hazardous materials, frozen material, and brittle, non-durable
aggregate, soil clods or rocks and/or any other materials that can break down and degrade over
time.
9. In general, the backfill soil requirements will depend on the future use of the land above the buried
line, but in most cases, excessive settlement of the pipe trench is not considered advisable or
acceptable. As such, the structural backfill compaction equipment should be appropriate for the
thickness of the loose lift being placed. The thickness of the loose lift being placed should be at
least two times the maximum particle size incorporated in the fill. Care should be taken not to
damage the pipe during compaction or compaction testing.
10. Fill lift thickness (including bedding) should generally be proportioned to achieve 95 percent or
more of a standard proctor (ASTM D689) maximum dry density (MDD) or 90 percent or more of a
modified proctor (ASTM D1557) MDD, depending on the state practices (in general the modified
proctor is required in California and for projects in the jurisdiction of the Army Corps of Engineers).
For backfills within the upper portions of roadway subgrades, the general requirement for soil
compaction is usually increased to 100 percent or more of the standard proctor MDD and 95
percent or more of the modified proctor MDD.
11. Soil compaction should be performed at a moisture content generally near optimum moisture
content determined by either standard or modified proctor, and ideally within 3 percent below to
1 percent over the optimum for a standard proctor, and from 2 percent below to 2 percent above
optimum for a modified proctor.
12. In some instances, fill areas are difficult to access. In such cases a low-strength soil-cement slurry
can be used in the place of compacted fill soil. In general, such fills should be rated to have a 28-
day strength of 75 to 125 psi, which in some areas is referred to as a “1-sack” slurry. It should be
noted that these materials are wet and require a period of 2 days (24 hours) to cure before
additional fill can be placed above it. Testing of this material can be done using concrete cylinder
compression strength testing equipment, but care is needed in removing the test specimens from
the molds. Field testing using the ball method and spread or flow testing is also acceptable.
13. Quality control testing should be provided on structural backfill to assist the contractor in meeting
project specifications. Proctor testing should be performed on each soil type, and one-point field
proctors should be used to verify the soil types during compaction testing. If compaction testing is
performed with a nuclear density gauge, it should be periodically correlated with a sand cone test
for each soil type.

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January 19, 2021
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14. Density testing should be performed on structural backfill per project specifications and or
jurisdictional requirements, but not less than once per 12 inches elevation in each area, and
additional tests for each additional 500 linear-foot section or portion thereof.

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Project No. 20-296889.2
January 19, 2021
Page C-ix

CAST-IN-PLACE CONCRETE
SLABS-ON-GRADE/STRUCTURES/PAVEMENTS
1. In general, construction should proceed per the governing jurisdictional guidelines for the project
site, including but not limited to the applicable American Concrete Institute (ACI), International
Code Council (ICC), State Department of Transportation, City and/or County, Army Corps of
Engineers, Federal Aviation, Occupational Safety and Health Administration (OSHA), and any other
governing standard details and specifications. In areas where multiple standards are applicable the
more stringent should be considered. Work should be performed by qualified, licensed contractors
with experience in the specific type of work in the area of the site.
2. Cast-in-place concrete (concrete) in this section is considered to apply to the installation of cast-
in-place concrete slabs on grade, including reinforced and non-reinforced slabs, structures, and
pavements.
3. In areas where concrete is bearing on prepared subgrade or structural fill soils, testing and approval
of this work should be completed prior to the beginning of concrete construction.
4. In locations where a concrete is approved to bear on in-place (native) soil or in locations where
approved documented fills have been exposed to weather conditions after approval, a concrete
subgrade evaluation should be performed prior to the placement of reinforcing steel and or
concrete. This can consist of probing with a “t”-handled rod, borings, penetrometer testing,
dynamic cone penetration testing and/or other methods requested by the geotechnical engineer
and/or inspector. Where unsuitable, wet, or frozen bearing material is encountered, the
geotechnical engineer should be consulted for additional recommendations.
5. Slabs on grade should be placed on a 4-inch thick or more capillary barrier consisting of non-
corrosive (more than 2,000 ohm-cm resistivity, less than 50 ppm chloride content and less than 0.1
percent sulfates) aggregate base or open-graded aggregate material. This material should be
compacted or consolidated per the recommendations of the structural engineer or otherwise would
be covered by the General Considerations for EARTHWORK.
6. Depending on the site conditions and climate, vapor barriers may be required below in-door grade-
slabs to receive flooring. This reduces the opportunity for moisture vapor to accumulate in the slab,
which could degrade flooring adhesive and result in mold or other problems. Vapor barriers should
be specified by the structural engineer and/or architect. The installation of the barrier should be
inspected to evaluate the correct product and thickness is used, and that it has not been damaged
or degraded.
7. At times when rainfall is predicted during construction, a mud-mat or a thin concrete layer can be
placed on prepared and approved subgrades prior to the placement of reinforcing steel or tendons.
This serves the purpose of protecting the subgrades from damage once the reinforcement
placement has begun.
8. Prior to the placement of concrete, exposed subgrade or base material and forms should be wetted,
and form release compounds should be applied. Reinforcement support stands or ties should be

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Project No. 20-296889.2
January 19, 2021
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checked. Concrete bases or subgrades should not be so wet that they are softened or have standing
water.
9. For a cast-in-place concrete, the form dimensions, reinforcement placement and cover, concrete
mix design, and other code requirements should be carefully checked by an inspector before and
during placement. The reinforcement should be specified by the structural engineering drawings
and calculations.
10. For post-tension concrete, an additional check of the tendons is needed, and a tensioning
inspection form should be prepared prior to placement of concrete.
11. For Portland cement pavements, forms an additional check of reinforcing dowels should performed
per the design drawings.
12. During placement, concrete should be tested, and should meet the ACI and jurisdictional
requirements and mix design targets for slump, air entrainment, unit weight, compressive strength,
flexural strength (pavements), and any other specified properties. In general concrete should be
placed within 90 minutes of batching at a temperature of less than 90 degrees Fahrenheit. Adding
of water to the truck on the jobsite is generally not encouraged.
13. Concrete mix designs should be created by the accredited and jurisdictionally approved supplier to
meet the requirements of the structural engineer. In general, a water/cement ratio of 0.45 or less is
advisable, and aggregates, cement, flyash, and other constituents should be tested to meet ASTM
C-33 standards, including Alkali Silica Reaction (ASR). To further mitigate the possibility of concrete
degradation from corrosion and ASR, Type II or V Portland Cement should be used, and fly ash
replacement of 25 percent is also recommended. Air entrained concrete should be used in areas
where concrete will be exposed to frozen ground or ambient temperatures below freezing.
14. Control joints are recommended to improve the aesthetics of the finished concrete by allowing for
cracking within partially cut or grooved joints. The control joints are generally made to depths of
about 1/4 of the slab thickness and are generally completed within the first day of construction.
The spacing should be laid out by the structural engineer and is often in a square pattern. Joint
spacing is generally 5 to 15 feet on-center but this can vary and should be decided by the structural
engineer. For pavements, construction joints are generally considered to function as control joints.
Post-tensioned slabs generally do not have control joints.
15. Some slabs are expected to meet flatness and levelness requirements. In those cases, testing for
flatness and levelness should be completed as soon as possible, usually the same day as concrete
placement, and before cutting of control joints if possible. Roadway smoothness can also be
measured and is usually specified by the jurisdictional owner if is required.
16. Prior to tensioning of post-tension structures, placement of soil backfills or continuation of building
on newly placed concrete, a strength requirement is generally required, which should be specified
by the structural engineer. The strength progress can be evaluated using concrete compressive
strength cylinders or maturity monitoring in some jurisdictions. Advancing with backfill, additional
concrete work or post-tensioning without reaching strength benchmarks could result in damage
and failure of the concrete, which could result in danger and harm to nearby people and property.

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Project No. 20-296889.2
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17. In general, concrete should not be exposed to freezing temperatures in the first 7 days after
placement, which may require insulation or heating. Additionally, in hot or dry, windy weather,
misting, covering with wet burlap or the use of curing compounds may be called for to reduce
shrinkage cracking and curling during the first 7 days.

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Project No. 20-296889.2
January 19, 2021
Page C-xii

FOUNDATIONS
1. In general, construction should proceed per the governing jurisdictional guidelines for the project
site, including but not limited to the applicable American Concrete Institute (ACI), International
Code Council (ICC), State Department of Transportation, City and/or County, Army Corps of
Engineers, Federal Aviation, Occupational Safety and Health Administration (OSHA), and any other
governing standard details and specifications. In areas where multiple standards are applicable the
more stringent should be considered. Work should be performed by qualified, licensed contractors
with experience in the specific type of work in the area of the site.
2. Foundations in this section are considered to apply to the construction of structural supports which
directly transfer loads from man-made structures into the earth. In general, these include shallow
foundations and deep foundations. Shallow foundations are generally constructed for the purpose
of distributing the structural loads horizontally over a larger area of earth. Some types of shallow
foundations (or footings) are spread footings, continuous footings, mat foundations, and reinforced
slabs-on-grade. Deep foundations are generally designed for the purpose of distributing the
structural loads vertically deeper into the soil using end bearing and side friction. Some types of
deep foundations are driven piles, auger-cast piles, drilled shafts, caissons, helical piers, and micro-
piles.
3. For shallow foundations, the minimum bearing depth considered should be greater than the
maximum design frost depth for the location of construction. This can be found on frost depth
maps (ICC), but the standard of practice in the city and/or county should also be consulted. In
general, the bearing depth should never be less than 18 inches below planned finished grades.
4. Shallow continuous foundations should be sized with a minimum width of 18 inches and isolated
spread footings should be a minimum of 24 inches in each direction. Foundation sizing, spacing,
and reinforcing steel design should be performed by a qualified structural engineer.
5. The geotechnical engineer will provide an estimated bearing capacity and settlement values for the
project based on soil conditions and estimated loads provided by the structural engineer. It is
assumed that appropriate safety factors will be applied by the structural engineer.
6. In areas where shallow foundations are bearing on prepared subgrade or structural fill soils, testing
and approval of this work should be completed prior to the beginning of foundation construction.
7. In locations where the shallow foundations are approved to bear on in-place (native) soil or in
locations where approved documented fills have been exposed to weather conditions after
approval, a foundation subgrade evaluation should be performed prior to the placement of
reinforcing steel. This can consist of probing with a “t”-handled rod, borings, penetrometer testing,
dynamic cone penetration testing and/or other methods requested by the geotechnical engineer
and/or inspector. Where unsuitable foundation bearing material is encountered, the geotechnical
engineer should be consulted for additional recommendations.
8. For shallow foundations to bear on rock, partially weathered rock, hard cemented soils, and/or
boulders, the entire foundation system should bear directly on such material. In this case, the rock
surface should be prepared so that it is clean, competent, and formed into a roughly horizontal,
stepped base. If that is not possible, then the entire structure should be underlain by a zone of

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January 19, 2021
Page C-xiii

structural fill. This may require the over-excavation in areas of rock removal and/or hard dig. In
general, this zone can vary in thickness, but it should be a minimum of 1 foot thick. The geotechnical
engineer should be consulted in this instance.
9. At times when rainfall is predicted during construction, a mud-mat or a thin concrete layer can be
placed on prepared and approved subgrades prior to the placement of reinforcing steel. This serves
the purpose of protecting the subgrades from damage once the reinforcing steel placement has
begun.
10. For cast-in-place concrete foundations, the excavations dimensions, reinforcing steel placement
and cover, structural fill compaction, concrete mix design, and other code requirements should be
carefully checked by an inspector before and during placement.
-----------------------------------------------------------------------------------------------------
11. For deep foundations, the geotechnical engineer will generally provide design charts that provide
foundations axial capacity and uplift resistance at various depths given certain-sized foundations.
These charts may be based on blow count data from drilling and or laboratory testing. In general
safety factors are included in these design charts by the geotechnical engineer.
12. In addition, the geotechnical engineer may provide other soil parameters for use in the lateral
resistance analysis. These parameters are usually raw data, and safety factors should be provided
by the shaft designer. Sometimes, direct shear and or tri-axial testing is performed for this analysis.
13. In general, the spacing of deep foundations is expected to be 6 shaft diameters or more. If that
spacing is reduced, a group reduction factor should be applied by the structural engineer to the
foundation capacities per FHWA guidelines. The spacing should not be less than 2.5 shaft diameters.
14. For deep foundations, a representative of the geotechnical engineer should be on-site to observe
the excavations (if any) to evaluate that the soil conditions are consistent with the findings of the
geotechnical report. Soil/rock stratigraphy will vary at times, and this may result in a change in the
planned construction. This may require the use of fall protection equipment to perform
observations close to an open excavation.
15. For driven foundations, a representative of the geotechnical engineer should be on-site to observe
the driving process and to evaluate that the resistance of driving is consistent with the design
assumptions. Soil/rock stratigraphy will vary at times and may this may result in a change in the
planned construction.
16. For deep foundations, the size, depth, and ground conditions should be verified during construction
by the geotechnical engineer and/or inspector responsible. Open excavations should be clean, with
any areas of caving and groundwater seepage noted. In areas below the groundwater table, or
areas where slurry is used to keep the trench open, non-destructive testing techniques should be
used as outlined below.
17. Steel members including structural steel piles, reinforcing steel, bolts, threaded steel rods, etc.
should be evaluated for design and code compliance prior to pick-up and placement in the
foundation. This includes verification of size, weight, layout, cleanliness, lap-splices, etc. In addition,
if non-destructive testing such as crosshole sonic logging or gamma-gamma logging is required,
access tubes should be attached to the steel reinforcement prior to placement, and should be

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January 19, 2021
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relatively straight, capped at the bottom, and generally kept in-round. These tubes must be filled
with water prior to the placement of concrete.
18. In cases where steel welding is required, this should be observed by a certified welding inspector.
19. In many cases, a crane will be used to lower steel members into the deep foundations. Crane picks
should be carefully planned, including the ground conditions at placement of outriggers, wind
conditions, and other factors. These are not generally provided in the geotechnical report but can
usually be provided upon request.
20. Cast-in-place concrete, grout or other cementations materials should be pumped or distributed to
the bottom of the excavation using a tremie pipe or hollow stem auger pipe. Depending on the
construction type, different mix slumps will be used. This should be carefully checked in the field
during placement, and consolidation of the material should be considered. Use of a vibrator may
be called for.
21. For work in a wet excavation (slurry), the concrete placed at the bottom of the excavation will
displace the slurry as it comes up. The upper layer of concrete that has interacted with the slurry
should be removed and not be a part of the final product.
22. Bolts or other connections to be set in the top after the placement is complete should be done
immediately after final concrete placement, and prior to the on-set of curing.
23. For shafts requiring crosshole sonic logging or gamma-gamma testing, this should be performed
within the first week after placement, but not before a 2-day curing period. The testing company
and equipment manufacturer should provide more details on the requirements of the testing.
24. Load testing of deep foundations is recommended, and it is often a project requirement. In some
cases, if test piles are constructed and tested, it can result in a significant reduction of the amount
of needed foundations. The load testing frame and equipment should be sized appropriately for
the test to be performed and should be observed by the geotechnical engineer or inspector as it is
performed. The results are provided to the structural engineer for approval.

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Project No. 20-296889.2
January 19, 2021
Page C-xv

LATERALLY LOADED STRUCTURES - RETAINING WALLS/SLOPES/DEEP
FOUNDATIONS/MISCELLANEOUS
1. In general, construction should proceed per the governing jurisdictional guidelines for the project
site, including but not limited to the applicable American Concrete Institute (ACI), International
Code Council (ICC), State Department of Transportation, City and/or County, Army Corps of
Engineers, Federal Aviation, Occupational Safety and Health Administration (OSHA), and any other
governing standard details and specifications. In areas where multiple standards are applicable the
more stringent should be considered. Work should be performed by qualified, licensed contractors
with experience in the specific type of work in the area of the site.
2. Laterally loaded structures for this section are generally meant to describe structures that are
subjected to loading roughly horizontal to the ground surface. Such structures include retaining
walls, slopes, deep foundations, tall buildings, box culverts, and other buried or partially buried
structures.
3. The recommendations put forth in General Geotechnical Design and Construction Considerations
for FOUNDATIONS, CAST-IN-PLACE CONCRETE, EARTHWORK, and SUBGRADE PREPARATION
should be reviewed, as they are not all repeated in this section, but many of them will apply to the
work. Those recommendations are incorporated by reference herein.
4. Laterally loaded structures are generally affected by overburden pressure, water pressure,
surcharges, and other static loads, as well as traffic, seismic, wind, and other dynamic loads. The
structural engineer must account for these loads. In addition, eccentric loading of the foundation
should be evaluated and accounted for by the structural engineer. The structural engineer is also
responsible for applying the appropriate factors of safety to the raw data provided by the
geotechnical engineer.
5. The geotechnical report should provide data regarding soil lateral earth pressures, seismic design
parameters, and groundwater levels. In the report the pressures are usually reported as raw data in
the form of equivalent fluid pressures for three cases. 1. Static is for soil pressure against a structure
that is fixed at top and bottom, like a basement wall or box culvert. 2. Active is for soil pressure
against a wall that is free to move at the top, like a retaining wall. 3. Passive is for soil that is resisting
the movement of the structure, usually at the toe of the wall where the foundation and embedded
section are located. The structural engineer is responsible for deciding on safety factors for design
parameters and groundwater elevations based on the raw data in the geotechnical report.
6. Generally speaking, direct shear or tri-axial shear testing should be performed for this evaluation in
cases of soil slopes or unrestrained soil retaining walls over 6 feet in height or in lower walls in some
cases based on the engineer’s judgment. For deep foundations and completely buried structures,
this testing will be required per the discretion of the structural engineer.
7. For non-confined retaining walls (walls that are not attached at the top) and slopes, a geotechnical
engineer should perform overall stability analysis for sliding, overturning, and global stability. For
walls that are structurally restrained at the top, the geotechnical engineer does not generally
perform this analysis. Internal wall stability should be designed by the structural engineer.

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January 19, 2021
Page C-xvi

8. Cut slopes into rock should be evaluated by an engineering geologist, and rock coring to identify
the orientation of fracture plans, faults, bedding planes, and other features should be performed.
An analysis of this data will be provided by the engineering geologist to identify modes of failure
including sliding, wedge, and overturning, and to provide design and construction
recommendations.
9. For laterally loaded deep foundations that support towers, bridges or other structures with high
lateral loads, geotechnical reports generally provide parameters for design analysis which is
performed by the structural engineer. The structural engineer is responsible for applying
appropriate safety factors to the raw data from the geotechnical engineer.
10. Construction recommendations for deep foundations can be found in the General Geotechnical
Design and Construction Considerations-FOUNDATIONS section.
11. Construction of retaining walls often requires temporary slope excavations and shoring, including
soil nails, soldier piles and lagging or laid-back slopes. This should be done per OSHA requirements
and may require specialty design and contracting.
12. In general, surface water should not be directed over a slope or retaining wall but should be
captured in a drainage feature trending parallel to the slope, with an erosion protected outlet to
the base of the wall or slope.
13. Waterproofing for retaining walls is generally required on the backfilled side, and they should be
backfilled with an 18-inch zone of open graded aggregate wrapped in filter fabric or a synthetic
draining product, which outlets to weep holes or a drain at the base of the wall. The purpose of this
zone, which is immediately behind the wall is to relieve water pressures from building behind the
wall.
14. Backfill compaction around retaining walls and slopes requires special care. Lighter equipment
should be considered, and consideration to curing of cementitious materials used during
construction will be called for. Additionally, if mechanically stabilized earth walls are being
constructed, or if tiebacks are being utilized, additional care will be necessary to avoid damaging
or displacing the materials. Use of heavy or large equipment, and/or beginning of backfill prior to
concrete strength verification can create dangers to construction and human safety. Please refer to
the General Geotechnical Design and Construction Considerations-CAST-IN-PLACE CONCRETE
section. These concerns will also apply to the curing of cell grouting within reinforced masonry
walls.
15. Usually safety features such as handrails are designed to be installed at the top of retaining walls
and slopes. Prior to their installation, workers in those areas will need to be equipped with
appropriate fall protection equipment.

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Project No. 20-296889.2
January 19, 2021
Page C-xvii

EXCAVATION AND DEWATERING
1. In general, construction should proceed per the governing jurisdictional guidelines for the project
site, including but not limited to the applicable American Concrete Institute (ACI), International
Code Council (ICC), State Department of Transportation, City and/or County, Army Corps of
Engineers, Federal Aviation, Occupational Safety and Health Administration (OSHA), and any other
governing standard details and specifications. In areas where multiple standards are applicable the
more stringent should be considered. Work should be performed by qualified, licensed contractors
with experience in the specific type of work in the area of the site.
2. Excavation and Dewatering for this section are generally meant to describe structures that are
intended to create stable, excavations for the construction of infrastructure near to existing
development and below the groundwater table.
3. The recommendations put forth in General Geotechnical Design and Construction Considerations
for LATERALLY LOADED STRUCTURES, FOUNDATIONS, CAST-IN-PLACE CONCRETE, EARTHWORK,
and SUBGRADE PREPARATION should be reviewed, as they are not all repeated in this section, but
many of them will apply to the work. Those recommendations are incorporated by reference herein.
4. The site excavations will generally be affected by overburden pressure, water pressure, surcharges,
and other static loads, as well as traffic, seismic, wind, and other dynamic loads. The structural
engineer must account for these loads as described in Section 5.2 of this report. In addition,
eccentric loading of the foundation should be evaluated and accounted for by the structural
engineer. The structural engineer is also responsible for applying the appropriate factors of safety
to the raw data provided by the geotechnical engineer.
5. The geotechnical report should provide data regarding soil lateral earth pressures, seismic design
parameters, and groundwater levels. In the report the pressures are usually reported as raw data in
the form of equivalent fluid pressures for three cases. 1. Static is for soil pressure against a structure
that is fixed at top and bottom, like a basement wall or box culvert. 2. Active is for soil pressure
against a wall that is free to move at the top, like a retaining wall. 3. Passive is for soil that is resisting
the movement of the structure, usually at the toe of the wall where the foundation and embedded
section are located. The structural engineer is responsible for deciding on safety factors for design
parameters and groundwater elevations based on the raw data in the geotechnical report.
6. The parameters provided above are based on laboratory testing and engineering judgement. Since
numerous soil layers with different properties will be encountered in a large excavation,
assumptions and judgement are used to generate the equivalent fluid pressures to be used in
design. Factors of safety are not included in those numbers and should be evaluated prior to design.
7. Groundwater, if encountered will dramatically change the stability of the excavation. In addition,
pumping of groundwater from the bottom of the excavation can be difficult and costly, and it can
result in potential damage to nearby structures if groundwater drawdown occurs. As such, we
recommend that groundwater monitoring be performed across the site during design and prior to
construction to assist in the excavation design and planning.
8. Groundwater pumping tests should be performed if groundwater pumping will be needed during
construction. The pumping tests can be used to estimate drawdown at nearby properties, and will

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Project No. 20-296889.2
January 19, 2021
Page C-xviii

be needed to determine the hydraulic conductivity of the soil for the design of the dewatering
system.
9. For excavation stabilization in granular and dense soil, the use of soldier piles and lagging is
recommended. The soldier pile spacing and size should be determined by the structural engineer
based on the lateral loads provided in the report. In general, the spacing should be more than two
pile diameters, and less than 8 feet. Soldier piles should be advanced 5 feet or more below the base
of the excavation. Passive pressures from Section 5.2 can be used in the design of soldier piles for
the portions of the piles below the excavation.
10. If the piles are drilled, they should be grouted in-place. If below the groundwater table, the grouting
should be accomplished by tremie pipe, and the concrete should be a mix intended for placement
below the groundwater table. For work in a wet excavation, the concrete placed at the bottom of
the excavation will displace the water as it comes up. The upper layer of concrete that has interacted
with the water should be removed and not be a part of the final product. Lagging should be
specially designed timber or other lagging. The temporary excavation will need to account for
seepage pressures at the toe of the wall as well as hydrostatic forces behind the wall.
11. Depending on the loading, tie back anchors and/or soil nails may be needed. These should be
installed beyond the failure envelope of the wall. This would be a plane that is rotated upward 55
degrees from horizontal. The strength of the anchors behind this plane should be considered, and
bond strength inside the plane should be ignored. If friction anchors are used, they should extend
10 feet or more beyond the failure envelope. Evaluation of the anchor length and encroachment
onto other properties, and possible conflicts with underground utilities should be carefully
considered. Anchors are typically installed 25 to 40 degrees below horizontal. The capacity of the
anchors should be checked on 10% of locations by loading to 200% of the design strength. All
should be loaded to 120% of design strength, and should be locked off at 80%
12. The shoring and tie backs should be designed to allow less than ½ inch of deflection at the top of
the excavation wall, where the wall is within an imaginary 1:1 line extending downward from the
base of surrounding structures. This can be expanded to 1 inch of deflection if there is no nearby
structure inside that plane. An analysis of nearby structures to locate their depth and horizontal
position should be conducted prior to shored excavation design.
13. If the excavations will encroach below the groundwater table, allowances for drainage behind and
through the lagging should be made. The drainage can be accomplished by using an open-graded
gravel material that is wrapped in geotextile fabric. The lagging should allow for the collected water
to pass through the wall at select locations into drainage trenches below the excavation base. These
trenches should be considered as sump areas where groundwater can be pumped out of the
excavation.
14. The pumped groundwater needs to be handled properly per jurisdictional guidelines.
15. In general, surface water should not be directed over a slope or retaining wall but should be
captured in a drainage feature trending parallel to the slope, with an erosion protected outlet to
the base of the wall or slope.

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Project No. 20-296889.2
January 19, 2021
Page C-xix

16. Safety features such as handrails or barriers are to be designed to be installed at the top of retaining
walls and slopes. Prior to their installation, workers in those areas will need to be equipped with
appropriate fall protection equipment.

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Project No. 20-296889.2
January 19, 2021
Page C-xx

Waterproofing and Back Drainage
1. In general, construction should proceed per the governing jurisdictional guidelines for the project
site, including but not limited to the applicable American Concrete Institute (ACI), International
Code Council (ICC), State Department of Transportation, City and/or County, Army Corps of
Engineers, Federal Aviation, Occupational Safety and Health Administration (OSHA), and any other
governing standard details and specifications. In areas where multiple standards are applicable the
more stringent should be considered. Work should be performed by qualified, licensed contractors
with experience in the specific type of work in the area of the site.
2. Waterproofing and Back drainage structures for this section are generally meant to describe
permanent subgrade structures that are planned to be below the historic high groundwater
elevation of 20 feet below existing grades.
3. The recommendations put forth in General Geotechnical Design and Construction Considerations
for FOUNDATIONS, CAST-IN-PLACE CONCRETE, EARTHWORK, and SUBGRADE PREPARATION
should be reviewed, as they are not all repeated in this section, but many of them will apply to the
work. Those recommendations are incorporated by reference herein.
4. In general, surface water should not be directed over a slope or retaining wall but should be
captured in a drainage feature trending parallel to the slope, with an erosion protected outlet to
the base of the wall or slope.
5. Waterproofing for retaining walls is generally required on the backfilled side, and they should be
backfilled with an 18-inch zone of open graded aggregate wrapped in filter fabric or a synthetic
draining product, which outlets to weep holes or a drain at the base of the wall. The purpose of this
zone, which is immediately behind the wall is to relieve water pressures from building behind the
wall.
6. For the basement walls on this site, sump pumps will be needed to reduce the build-up of water in
the basement. The design should be for a historic high groundwater level of 20 feet bgs. The
pumping system should be designed to keep the slab and walls relatively dry so that mold,
efflorescence, and other detrimental effects to the concrete structure will not result.
7. Backfill compaction around retaining walls and slopes requires special care. Lighter equipment
should be considered, and consideration to curing of cementitious materials used during
construction will be called for. Additionally, if mechanically stabilized earth walls are being
constructed, or if tiebacks are being utilized, additional care will be necessary to avoid damaging
or displacing the materials. Use of heavy or large equipment, and/or beginning of backfill prior to
concrete strength verification can create dangers to construction and human safety. Please refer to
the General Geotechnical Design and Construction Considerations-CAST-IN-PLACE CONCRETE
section. These concerns will also apply to the curing of cell grouting within reinforced masonry
walls.

Geotechnical Report
Project No. 20-296889.2
January 19, 2021
Page C-xxi

CHEMICAL TREATMENT OF SOIL
1. In general, construction should proceed per the governing jurisdictional guidelines for the project
site, including but not limited to the applicable American Concrete Institute (ACI), International
Code Council (ICC), State Department of Transportation, State Department of Environmental
Quality, the US Environmental Protection Agency, City and/or County, Army Corps of Engineers,
Federal Aviation, Occupational Safety and Health Administration (OSHA), and any other governing
standard details and specifications. In areas where multiple standards are applicable the more
stringent should be considered. Work should be performed by qualified, licensed contractors with
experience in the specific type of work in the area of the site.
2. Chemical treatment of soil for this section is generally meant to describe the process of improving
soil properties for a specific purpose, using cement or chemical lime.
3. A mix design should be performed by the geotechnical engineer to help it meet the specific
strength, plasticity index, durability, and/or other desired properties. The mix design should be
performed using the proposed chemical lime or cement proposed for use by the contractor, along
with samples of the site soil that are taken from the material to be used in the process.
4. For the mix design the geotechnical engineer should perform proctor testing to determine
optimum moisture content of the soil, and then mix samples of the soil at 3 percent above optimum
moisture content with varying concentrations of lime or cement. The samples will be prepared and
cured per ASTM standards, and then after 7-days for curing, they will be tested for compression
strength. Durability testing goes on for 28 days.
5. Following this testing, the geotechnical engineer will provide a recommended mix ratio of cement
or chemical lime in the geotechnical report for use by the contractor. The geotechnical engineer
will generally specify a design ratio of 2 percent more than the minimum to account for some error
during construction.
6. Prior to treatment, the in-place soil moisture should be measured so that the correct amount of
water can be used during construction. Work should not be performed on frozen ground.
7. During construction, special considerations for construction of treated soils should be followed. The
application process should be conducted to prevent the loss of the treatment material to wind
which might transport the materials off site, and workers should be provided with personal
protective equipment for dust generated in the process.
8. The treatment should be applied evenly over the surface, and this can be monitored by use of a
pan placed on the subgrade. This can also be tested by preparing test specimens from the in-place
mixture for laboratory testing.
9. Often, after or during the chemical application, additional water may be needed to activate the
chemical reaction. In general, it should be maintained at about 3 percent or more above optimum
moisture. Following this, mixing of the applied material is generally performed using specialized
equipment.
10. The total amount of chemical provided can be verified by collecting batch tickets from the delivery
trucks, and the depth of the treatment can be verified by digging of test pits, and the use of reagents
that react with lime and or cement.

Geotechnical Report
Project No. 20-296889.2
January 19, 2021
Page C-xxii

11. For the use of lime treatment, compaction should be performed after a specified amount of time
has passed following mixing and re-grading. For concrete, compaction should be performed
immediately after mixing and re-grading. In both cases, some swelling of the surface should be
expected. Final grading should be performed the following day of the initial work for lime treatment,
and within 2 to 4 hours for soil cement.
12. Quality control testing of compacted treated subgrades should be performed per the
recommendations of the geotechnical report, and generally in accordance with General
Geotechnical Design and Construction Considerations - EARTHWORK

Geotechnical Report
Project No. 20-296889.2
January 19, 2021
Page C-xxiii

PAVING
1. In general, construction should proceed per the governing jurisdictional guidelines for the project
site, including but not limited to the applicable American Concrete Institute (ACI), International
Code Council (ICC), State Department of Transportation, City and/or County, Army Corps of
Engineers, Federal Aviation, Occupational Safety and Health Administration (OSHA), and any other
governing standard details and specifications. In areas where multiple standards are applicable the
more stringent should be considered. Work should be performed by qualified, licensed contractors
with experience in the specific type of work in the area of the site.
2. Paving for this section is generally meant to describe the placement of surface treatments on travel-
ways to be used by rubber-tired vehicles, such as roadways, runways, parking lots, etc.
3. The geotechnical engineer is generally responsible for providing structural analysis to recommend
the thickness of pavement sections, which can include asphalt, concrete pavements, aggregate
base, cement or lime treated aggregate base, and cement or lime treated subgrades.
4. The civil engineer is generally responsible for determining which surface finishes and mixes are
appropriate, and often the owner, general contractor and/or other party will decide on lift thickness,
the use of tack coats and surface treatments, etc.
5. The geotechnical engineer will generally be provided with the planned traffic loading, as well as
reliability, design life, and serviceability factors by the jurisdiction, traffic engineer, designer, and/or
owner. The geotechnical study will provide data regarding soil resiliency and strength. A pavement
modeling software is generally used to perform the analysis for design, however, jurisdictional
minimum sections also must be considered, as well as construction considerations and other
factors.
6. The geotechnical report will generally provide pavement section thicknesses if requested.
7. For construction of overlays, where new pavement is being placed on old pavement, an evaluation
of the existing pavement is needed, which should include coring the pavement, evaluation of the
overall condition and thickness of the pavement, and evaluation of the pavement base and
subgrade materials.
8. In general, the existing pavement is milled and treated with a tack coat prior to the placement of
new pavement for the purpose of creating a stronger bond between the old and new material. This
is also a way of removing aged asphalt and helping to maintain finished grades closer to existing
conditions grading and drainage considerations.
9. If milling is performed, a minimum of 2 inches of existing asphalt should be left in-place to reduce
the likelihood of equipment breaking through the asphalt layer and destroying its integrity. After
milling and before the placement of tack coat, the surface should be evaluated for cracking or
degradation. Cracked or degraded asphalt should be removed, spanned with geosynthetic
reinforcement, or be otherwise repaired per the direction of the civil and or geotechnical engineer
prior to continuing construction. Proof rolling may be requested.
10. For pavements to be placed on subgrade or base materials, the subgrade and base materials should
be prepared per the General Geotechnical Design and Construction Considerations – EARTHWORK
section.

Geotechnical Report
Project No. 20-296889.2
January 19, 2021
Page C-xxiv

11. Following the proof rolling as described in the General Geotechnical Design and Construction
Considerations – EARTHWORK section, the application of subgrade treatment, base material, and
paving materials can proceed per the recommendations in the geotechnical report and/or project
plans. The placement of pavement materials or structural fills cannot take place on frozen ground.
12. The placement of aggregate base material should conform to the jurisdictional guidelines. In
general, the materials should be provided by an accredited supplier, and the material should meet
the standards of ASTM C-33. Material that has been stockpiled and exposed to weather including
wind and rain should be retested for compliance since fines could be lost. Frozen material cannot
be used.
13. The placement of asphalt material should conform to the jurisdictional guidelines. In general, the
materials should be provided by an accredited supplier, and the material should meet the standards
of ASTM C-33. The material can be placed in a screed by end-dumping, or it can be placed directly
on the paving surface. The temperature of the mix at placement should generally be on the order
of 300 degrees Fahrenheit at time of placement and screeding.
14. Compaction of the screeded asphalt should begin as soon as practical after placement, and initial
rolling should be performed before the asphalt has cooled significantly. Compaction equipment
should have vibratory capabilities and should be of appropriate size and weight given the thickness
of the lift being placed and the sloping of the ground surface.
15. In cold and/or windy weather, the cooling of the screeded asphalt is a quality issue, so preparations
should be made to perform screeding immediately after placement, and compaction immediately
after screeding.
16. Quality control testing of the asphalt should be performed during placement to verify compaction
and mix design properties are being met and that delivery temperatures are correct. Results of
testing data from asphalt laboratory testing should be provided within 24 hours of the paving.

Geotechnical Report
Project No. 20-296889.2
January 19, 2021
Page C-xxv

SITE GRADING AND DRAINAGE
1. In general, construction should proceed per the governing jurisdictional guidelines for the project
site, including but not limited to the applicable American Concrete Institute (ACI), International
Code Council (ICC), State Department of Transportation, State Department of Environmental
Quality, the US Environmental Protection Agency, City and/or County, Army Corps of Engineers,
Federal Aviation, Occupational Safety and Health Administration (OSHA), and any other governing
standard details and specifications. In areas where multiple standards are applicable the more
stringent should be considered. Work should be performed by qualified, licensed contractors with
experience in the specific type of work in the area of the site.
2. Site grading and drainage for this section is generally meant to describe the effect of new
construction on surface hydrology, which impacts the flow of rainfall or other water running across,
onto or off-of, a newly constructed or modified development.
3. This section does not apply to the construction of site grading and drainage features.
Recommendations for the construction of such features are covered in General Geotechnical Design
and Construction Considerations for Earthwork – Structural Fills section and Underground Pipeline
Installation – Backfill section.
4. In general, surface water flows should be directed towards storm drains, natural channels, retention
or detention basins, swales, and/or other features specifically designed to capture, store, and or
transmit them to specific off-site outfalls.
5. The surface water flow design is generally performed by a site civil engineer, and it can be impacted
by hydrology, roof lines, and other site structures that do not allow for water to infiltrate into the
soil, and that modify the topography of the site.
6. Soil permeability, density, and strength properties are relevant to the design of storm drain systems,
including dry wells, retention basins, swales, and others. These properties are usually only provided
in a geotechnical report if specifically requested, and recommendations will be provided in the
geotechnical report in those cases.
7. Structures or site features that are not a part of the surface water drainage system should not be
exposed to surface water flows, standing water or water infiltration. In general, roof drains and
scuppers, exterior slabs, pavements, landscaping, etc. should be constructed to drain water away
from structures and foundations. The purpose of this is to reduce the opportunity for water damage,
erosion, and/or altering of structural soil properties by wetting. In general, a 5 percent or more
slope away from foundations, structural fills, slopes, structures, etc. should be maintained.
8. Special considerations should be used for slopes and retaining walls, as described in the General
Geotechnical Design and Construction Considerations - LATERALLY LOADED STRUCTURES section.
9. Additionally, landscaping features including irrigation emitters and plants that require large
amounts of water should not be placed near to new structures, as they have the potential to alter
soil moisture states. Changing of the moisture state of soil that provides structural support can lead
to damage to the supported structures.