SW4220901_Soils/Geotechnical Report_20220921

ECS Southeast, LLP
Geotechnical Engineering Report
Davidson Charter Academy
500 Biesecker Rd
Lexington, North Carolina
ECS Project Number 09:28038-B
May 19, 2022
Ec

May 19, 2022
Mr. Rick Ball
Bradley & Ball Architects, PA
5921-H West Friendly Avenue
Greensboro, North Carolina 27410
ECS Project No. 09.28038-B
Reference: Geotechnical Engineering Report
Davidson Charter Academy
500 Biesecker Rd.
Lexington, North Carolina
Dear Mr. Ball:
ECS Southeast, LLP (ECS) has completed the subsurface exploration, laboratory testing, and
geotechnical engineering analyses for the above -referenced project. Our services were performed in
general accordance with our agreed to scope of work. This report presents our understanding of the
geotechnical aspects of the project, the results of the field exploration conducted, and our
geotechnical design and construction recommendations for the project.
It has been our pleasure to be of service to you during the design phase of this project. We would
appreciate the opportunity to remain involved during the continuation of the design phase, and we
would like to provide our services during construction phase operations as well to verify subsurface
conditions assumed for this report. Should you have any questions concerning the information
contained in this report, or if we can be of further assistance to you, please contact us.
Respectfully submitted,
ECS Southeast, LLP
Muhannad Abdelgadir
Geotechnical Staff Project Manager
[e-mail]
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Sun Breza P.E.
Principal Engineer
NC License No. 029908
[e-mail]

Geotechnical Engineering Report— Davidson Charter Academy May 19, 2022
ECS Project No. 09:28038-8 Page i
TABLE OF CONTENTS
EXECUTIVE SUMMARY.............................................................................................................1
1.0
INTRODUCTION............................................................................................................2
2.0
PROJECT INFORMATION...............................................................................................3
2.1
SITE INFORMATION...........................................................................................................3
2.2
PROPOSED CONSTRUCTION..............................................................................................4
3.0
FIELD EXPLORATION AND LABORATORY TESTING..........................................................4
3.1
SUBSURFACE CHARACTERIZATION....................................................................................4
3.2
GROUNDWATER OBSERVATIONS......................................................................................6
3.3
LABORATORY TESTING......................................................................................................6
4.0
DESIGN RECOMMENDATIONS......................................................................................7
4.1
BUILDING/STRUCTURE DESIGN.........................................................................................7
4.1.1 Shallow Spread Footing Foundations.......................................................................7
4.1.2 Floor Slabs.................................................................................................................7
4.2
Seismic Design...................................................................................................................8
4.3
SITE DESIGN CONSIDERATIONS.........................................................................................9
4.3.1 Permanent Site Dewatering.....................................................................................9
4.3.2 Pavement Sections...................................................................................................9
5.0
SITE CONSTRUCTION RECOMMENDATIONS................................................................12
5.1
SUBGRADE PREPARATION...............................................................................................12
5.1.1 Existing Utilities......................................................................................................12
5.1.2 Stripping and Grubbing...........................................................................................12
5.1.3 Proofrolling.............................................................................................................13
5.2
EARTHWORK OPERATIONS..............................................................................................13
5.2.1 Expansive Soil.........................................................................................................13
5.2.2 Excavation Considerations......................................................................................14
5.2.3 Structural Fill Materials..........................................................................................14
5.2.4 Compaction.............................................................................................................15
5.3
FOUNDATIONS AND FLOOR SLABS..................................................................................16
5.4
PAVEMENTS.....................................................................................................................17
5.4.1 Subgrade Evaluation...............................................................................................17
5.4.2 Aggregate Base Course...........................................................................................17
5.4.3 Asphalt Pavement Construction.............................................................................18
5.5
Utility Installations...............................................................................................................18
5.6
General Construction Considerations..................................................................................18
6.0
CLOSING..........................................................................................................................19

Geotechnical Engineering Report— Davidson Charter Academy
ECS Project No. 09:28038-8
APPENDICES
Appendix A — Diagrams
• Site Location Diagram
• Boring Location Diagram
• Cross Section Location Diagram
Appendix B — Field Operations
• Reference Notes for Boring Logs
• Subsurface Exploration Procedure: Standard Penetration Testing (SPT)
• Boring Logs
Appendix C — Laboratory Testing
• Laboratory Test Results Summary
• Liquid and Plastic Limits Tests Results
May 19, 2022
Page ii

Geotechnical Engineering Report— Davidson Charter Academy
ECS Project No. 09:28038-8
EXECUTIVE SUMMARY
May 19, 2022
Page 1
This executive summary is intended as a very brief overview of the primary geotechnical conditions
that are expected to affect design and construction. Information gleaned from the executive
summary should not be utilized in lieu of reading the entire geotechnical report.
• Based on the boring logs and lab results, the site subsurface soils generally classified as SILT
/ SANDY SILT (MIL), ELASTIC SILT (MH), and SILTY SAND (SM), contain mica and trace
organics. The ELASTIC SILT (MH) soils are potentially expansive soils per the current North
Carolina Building Code and local practice. Based on laboratory testing and our experience,
these soils have a low potential for expansion (i.e., shrink -swell). We estimate that the
potential heave of footings, floor slabs, and pavements due to potential wetting and
settlement due to drying of potentially expansive soils will be less than 1 inch. As such, no
specific mitigation measures for footings, floor slabs due to potentially expansive soils are
recommended.
• The planned building(s) should be supported by conventional shallow foundations
consisting of column and/or strip footings bearing on engineered fill or natural soils or
approved existing fill. The footings should be sized using a net allowable soil bearing
pressure of 3,000 psf.
• Based on the N-values measured in the borings, a Seismic Site Class D designation is
appropriate for seismic design of the proposed building. Our experience indicates that
evaluation of seismic site class in North Carolina using N-values can be overly conservative.
Geophysical testing to measure shear wave velocities of the subsurface materials could be
performed for this project to potentially improve the site class.
• ECS should be retained to review the design documents for conformance with our
recommendations.
• ECS should be retained for construction materials testing and special inspections to
facilitate proper implementation of our recommendations.

Geotechnical Engineering Report— Davidson Charter Academy
ECS Project No. 09:28038-8
1.0 INTRODUCTION
May 19, 2022
Page 2
The purpose of this study was to provide geotechnical information for the design of new middle
school development for Davidson Charter Academy. The project will include a school building,
gymnasium, paved parking lots, and paved driveways. The recommendations developed for this
report are based on project information supplied by Bradley & Ball Architects, PA.
Our services were provided in accordance with our Proposal No. 09:28775-P, dated April 12, 2022,
as authorized by Rick Ball on Bradley & Ball Architects, PA, which includes our Terms and Conditions
of Service. ECS previously performed a geotechnical engineering report for the eastern portion of
the property for Davidson Charter Academy, ECS project No. 09:28038, dated January 9, 2018.
This report contains the procedures and results of our subsurface exploration and laboratory
testing programs, review of existing site conditions, engineering analyses, and recommendations
for the design and construction of the project and includes the following items.
a. A site location diagram and a boring location diagram.
b. Boring logs prepared in accordance with the standard practice for geotechnical
engineering. Ground surface elevations shown on the boring logs will be approximated by
interpolating from civil drawings or published topographical maps.
C. Laboratory test results.
d. Observations from our site reconnaissance including current site conditions, surface
drainage features, and surface topographic conditions.
e. A review of the published geologic conditions and their relevance to the planned
development.
f. A subsurface characterization based on the field exploration and laboratory tests
performed.
g. Recommended allowable soil bearing pressures for conventional shallow foundations
(spread footings) and estimates of predicted foundation settlement.
h. Recommendations for slab -on -grade design and construction, including recommendations
for subgrade materials and design modulus of subgrade reaction.
i. Recommendations for seismic site classification in accordance with the 2018 North Carolina
Building Code.
j. Recommendations for construction of the pavements, including a recommended California
Bearing Ratio (CBR) value. We will also include recommended pavement section
thicknesses based on assumed 18-kip Equivalent Single Axle Loads (ESALs).
k. Construction recommendations for site retaining walls, including lateral earth pressures.
I. Recommendations for subgrade preparation and earthwork, including excavation
considerations, engineered fill material, engineered fill placement, and other applicable
special considerations (e.g., rock excavation, existing fill, potentially expansive soil, deep fill
sections, unstable/unsuitable soils, shallow groundwater).
M. Recommendations for additional testing and/or consultation that might be required to
complete the geotechnical assessment and related engineering for this project.

Geotechnical Engineering Report— Davidson Charter Academy May 19, 2022
ECS Project No. 09:28038-8 Page 3
2.0 PROJECT INFORMATION
2.1 SITE INFORMATION
The site is located at 500 Biescker Road in Lexington, North Carolina, at the approximate location
shown in the following figure.
Figure 2.1.1. Site Location Shown Outlined in Red
The property is divided into two portions. The western portion of the property is currently
undeveloped and grassy -covered land. The eastern portion of the property is developed with a
school building and paved parking lots. The eastern portion of the site was mass graded in 2018
during the construction of the existing school. According to the preliminary drawing provided to us,
the site generally slopes upward from the west to the east with elevation ranging of 750 to 800 feet
above the mean sea level. Based on our site visit and a private utility locator, there is a stormwater
control devise located in the vacant grassy area adjacent B-01 and a sanitary sewer line near boring
B-09.

Geotechnical Engineering Report— Davidson Charter Academy May 19, 2022
ECS Project No. 09:28038-8 Page 4
2.2 PROPOSED CONSTRUCTION
The project involves a middle school building, gymnasium, and paved parking lots and driveways.
We assume that the proposed building will be 2 story, steel framed structure with non -loading
bearing metal stud walls with brick veneer. The gymnasium portion is load -bearing CIVIL) or precast
wall panels. The anticipated maximum structural loads, as provided to us, will be:
• Interior columns: 85 kips
• Perimeter columns: 55 kips
• Load bearing gymnasium wall: 5 kips per linear foot (klf)
• Typical non -load -bearing perimeter wall: 2 klf
• Loads at the bracing foundations: 120 kips
The anticipate finished floor elevation (FFE) is 788.30 feet above MSL. Based on existing site grades,
the site plan provided to us and our experience with similar projects, we anticipate that fill depths
up to 15 feet for general site grading of the building pad.
3.0 FIELD EXPLORATION AND LABORATORY TESTING
Our exploration procedures are explained in greater detail in Appendix B including the insert titled
Subsurface Exploration Procedure: Standard Penetration Testing (SPT). Our scope of work included
drilling 12 borings. Our borings were located with a handheld GPS unit and their approximate
locations are shown on the Boring Location Diagram in Appendix A.
3.1 SUBSURFACE CHARACTERIZATION
The subsurface conditions encountered appeared to be generally consistent with published
geological mapping. The following sections provide generalized characterizations of the soil and
rock strata. Please refer to the boring logs and generalized subsurface profiles in Appendix B.
Site Geology: The site is located within the Piedmont physiographic province. The Piedmont is
characterized by residual overburden soils weathered in place from the underlying igneous and
metamorphic rock. The topography and relief of the Piedmont uplands have developed from
differential weathering of the bedrock.
Because of the continued chemical and physical weathering, the bedrock in the Piedmont is now
generally covered with a mantle of soil that has weathered in place from the parent bedrock. These
soils have variable thicknesses and are referred to as residuum or residual soils. The residuum is
typically finer grained and has higher clay content near the surface because of the advanced
weathering. Similarly, the soils typically become coarser grained with increasing depth because of
decreased weathering. As the degree of weathering decreases, the residual soils generally retain
the overall appearance, texture, gradation and foliations of the parent rock.
The boundary between soil and rock in the Piedmont is not sharply defined. A transitional zone
termed "partially weathered rock" is normally found overlying the parent bedrock. Partially

Geotechnical Engineering Report- Davidson Charter Academy
ECS Project No. 09:28038-8
May 19, 2022
Page 5
weathered rock (PWR) is defined for engineering purposes as residual material with Standard
Penetration Resistances (N-values) exceeding 100 blows per foot. The transition between
hard/dense residual soils and partially weathered rock occurs at irregular depths due to variations
in degree of weathering. Also, it is not unusual to find lenses and boulders of hard rock and/or
zones of partially weathered rock within the soil mantel well above the general bedrock level.
According to the 1985 Geologic Map of North Carolina the site is underlain by intrusive rock, granitic
rock (Pennsylvanian to Permian) - Mega-crystic to equigranular. Lilesville granite.
Soil Stratigraphy: The general subsurface strata observed is summarized in the following:
Summary of Subsurface Conditions
Native Material
End of
Boring
N-Values
Surface Material
Description
Boring
No.
Depth, ft
(bpf)
Depth, ft
p
Residuum: Stiff to Hard SILT/SANDY SILT (ML),
0.08-22.0
11-34
B 01
Topsoil -1.0 In.
trace organics, contains mica, moist
25
Residuum: Loose SILTY SAND (SM), contain mica,
22.0 - 25.0
8
wet
Residuum: Stiff to Very Stiff SILT/SANDY SILT
0.08-22.0
12-27
(ML), contains mica, moist to wet
B-02
Topsoil -1.0 In.
25
Residuum: Medium Dense SILTY SAND (SM),
22.0 - 25.0
14
trace organics, contain mica, wet
Residuum: Stiff to Very Stiff SILT/SANDY SILT
0.08-22.0
10-24
(ML), trace organics, contains mica, moist to wet
B 03
Topsoil -1.0 In.
25
Residuum: Loose SILTY SAND (SM), contains
22.0 - 25.0
9
mica, wet
Residuum: Stiff to Very Stiff SILT/SANDY SILT
0.17-22.0
12-29
(ML), trace organics, contains mica, moist to wet
B 04
Topsoil - 2.0 In.
25
Residuum: Loose SILTY SAND (SM), contains
22.0 - 25.0
9
mica, wet
Residuum: Soft to Very Stiff SILT/SANDY SILT
0.08-16.5
5-30
(ML), contains mica, moist to wet
B 05
Topsoil -1.0 In.
40
Residuum: Loose to Medium Dense SILTY SAND
16.5-40.0
4-11
(SM), contains mica, wet
Residuum: Stiff ELASTIC SILT (MH), contains mica,
0.08 - 5.5
11-13
B 06
Topsoil -1.0 In.
moist
7.5
Residuum: Stiff SANDY SILT (ML), contains mica,
5.5 - 7.5
11
moist
Residuum: Stiff ELASTIC SILT (MH), contains mica,
0.08 - 5.5
13 -15
g-07
Topsoil -1.0 In.
moist
7.5
Residuum: Stiff SANDY SILT (ML), contains mica,
5.5 - 7.5
13
moist
Residuum: Stiff to Firm SANDY SILT (ML),
g-pg
Topsoil -1.0 In.
0.08 7.5
5 9
7.5
contains mica, moist to wet
Residuum: Firm to Very Stiff SANDY SILT (ML),
g-p9
Topsoil -1.0 In.
0.08 7.5
8 22
7.5
contains mica, moist
Residuum: Firm to Stiff ELASTIC SILT (MH),
0.08-5.5
8-13
B 10
Topsoil -1.0 In.
contains mica, moist
7.5
Residuum: Stiff SANDY SILT (ML), contains mica,
5.5 - 7.5
9
moist

Geotechnical Engineering Report— Davidson Charter Academy
ECS Project No. 09:28038-8
May 19, 2022
Page 6
Native Material
End of
Boring
N-Values
No.
Surface Material
Description
Boring
Depth, ft
(bpf)
Depth, ft
p
B 11
Topsoil —1.0 In.
0.08 7.5
8 11
Residuum: Firm to Stiff SANDY SILT (ML),
7.5
contains mica, moist
B_12
Topsoil —1.0 In.
0.08 7.5
10 14
Residuum: Stiff SANDY SILT (ML), contains mica,
7.5
moist
• bpf - blows per foot
• This summary is generalized and does not describe the actual conditions encountered in the borings. Detailed
descriptions of the encountered materials are listed on the Boring Records in the Appendix.
The soil stratification shown on the boring logs represents the soil conditions at the actual locations.
Variations in the stratification can occur between sample intervals and widely spaced boring
locations. The subsurface conditions at other locations on the site may differ from those found at
the boring locations. If different site conditions are encountered during construction, ECS should
be contacted to review our recommendations relative to the new information.
Please note that the ground surface elevations shown on the boring logs were estimated using a
preliminary site plan provided to us, drawing No. L-10013 dated on April 01, 2022. They should be
considered approximate and accurate to +/- several feet. Users of the elevation data do so at their
own risk.
3.2 GROUNDWATER OBSERVATIONS
Groundwater seepage into our borings was not observed during our exploration at the depths
explored. We observed borehole caving at a depth ranging from 11.68 to 17.0 feet for the borings
B-01 to B-05, which may be an indicator of groundwater presence. Variations in the long-term water
table may occur as a result of changes in precipitation, evaporation, surface water runoff,
construction activities, and other factors.
3.3 LABORATORY TESTING
Each sample was visually classified on the basis of texture and plasticity in accordance with ASTM
D2488 Standard Practice for Description and Identification of Soils (Visual -Manual Procedures) and
including USCS classification symbols, and ASTM D2487 Standard Practice for Classification for
Engineering Purposes (Unified Soil Classification System (USCS).
After classification, the samples were grouped in the major zones noted on the boring logs in
Appendix B. The group symbols for each soil type are indicated in parentheses along with the soil
descriptions. The stratification lines between strata on the logs are approximate; in situ, the
transitions may be gradual.
The laboratory testing consisted of selected tests performed on samples obtained during our field
exploration operations. Classification and index property tests were performed on representative
soil samples. Laboratory tests performed on selected samples included percent finer than No. 200
sieve test (ASTM D 1140), moisture content tests (ASTM D 2216), and Atterberg limit test (ASTM D
4318). Please refer to the laboratory testing summary in Appendix C.

Geotechnical Engineering Report— Davidson Charter Academy May 19, 2022
ECS Project No. 09:28038-8 Page 7
4.0 DESIGN RECOMMENDATIONS
4.1 BUILDING/STRUCTURE DESIGN
Once finished grades, building locations, and foundation layout are finalized, this information
should be provided to ECS. We may be able to modify these foundation recommendations once
additional project information is available.
4.1.1 Shallow Spread Footing Foundations
Provided subgrades and structural fills are prepared as discussed herein, and based on the design
foundation loads, it is our opinion that the proposed structure can be supported by conventional
shallow spread footing foundations. These include individual column footings and continuous wall
footings. The design of the shallow foundations should utilize the following parameters:
Foundation Design
Design Parameter
Column Footing
Wall Footing
Net Allowable Bearing PressureM
3,000 psf
3,000 psf
Stiff Low Plasticity Silts/Clays, Medium Dense Silty
Bearing Soil Material
Sands, or Structural fill
Minimum Width
24 inches
16 inches
Minimum Footing Embedment Depth (below
12 inchesz
12 inchesz
slab or finished grade) (z)
Estimated Total Settlement (3)
Less than 1 inch
Less than 1 inch
Estimated Differential Settlement (4)
Less than 1/2 inches
Less than 1/2 inches
between columns
over 50 feet
Notes:
(1) Net allowable bearing pressure is the applied pressure in excess of the surrounding overburden soils above the base of
the foundation. Assumes undocumented fill will be removed completely from within the expanded building footprint.
(2) For bearing considerations and frost penetration requirements.
(3) Based on assumed structural loads. If final loads are different, ECS must be contacted to update foundation
recommendations and settlement calculations.
(4) Based on anticipated range of column/wall loads and variability in borings. Differential settlement can be re-evaluated
once the foundation plans are more complete.
4.1.2 Floor Slabs
The on -site lower plasticity natural soils and/or new engineered fill are considered adequate for
support of the ground floor slabs, although moisture control during earthwork operations, including
the use of disking or appropriate drying equipment, may be necessary. A representative of ECS
should be called on to observe exposed subgrades prior to the placement of the slab base course
or engineered fill to verify that adequate subgrade preparation has been achieved. Proofrolling
using a drum roller or loaded dump truck should be performed at that time. Once subgrades have
been determined to be firm and unyielding, the base course or engineered fill can be placed.

Geotechnical Engineering Report— Davidson Charter Academy
ECS Project No. 09:28038-8
May 19, 2022
Page 8
We understand that the ground floor slabs -on -grade will be at or above finish exterior grades
around the entire building footprints. For this case, the 2018 North Carolina Building Code does
not require dam proofing or waterproofing of the slab. However, depending on floor coverings and
building use, a capillary break layer and vapor retarder should be installed to reduce excessive
moisture from coming in contact with the concrete floor slab from the soils below.
The following graphic depicts our soil -supported slab recommendations:
Vapor Retarder or Vapor
Concrete Slab Barrier
0006 o 0o 00 o uo vO O U` Uo
0 0 0 0 00 0 0000
0 0� 0 o o o 0 0 0 0 0 o o Base Course
Firm, Compacted Soil Subgrade
Figure 4.1.2.1- Floor Slab Section
1. Base Course Layer Thickness: 4 inches
2. Base Course Layer Material: A compactable granular fill that will remain adequate and support
construction traffic. At least 10% to 30% of the material should pass a No. 100 sieve with a maximum
aggregate size of % inch. Adequate materials are GRAVEL (ABC, GW, GW-SM), SAND (SP-SM, SW-SM),
and SILTY SAND (SM) with less than 30% fines.
3. Base Course Layer Material should be compacted to at least 98% maximum dry density per ASTM D698.
4. Undisturbed natural subgrade should proofroll as firm and unyielding. Upper 1 foot of structural fill
subgrade should be compacted to at least 98% maximum dry density per ASTM D698
5. Vapor Barrier or Vapor Retarder — Refer to ACI 302.1R-04 Guide for Concrete Floor and Slab
Construction and ASTM E 1643 Standard Practice for Installation of Water Vapor Retarders Used in
Contact with Earth or Granular Fill under Concrete Slabs for recommendations on this issue.
Additionally, environmental vapor intrusions considerations should be taken into account by the vapor
barrier/vapor retarder material selection and design.
Provided a base course layer is implemented in the slab section, the slabs may be designed using a
modulus of subgrade reaction of 110 psi/in. This value is applicable for design of slabs subject to
point loads and should be reduced based on loaded area for uniform sustained distributed loads.
Ground -supported slabs should be isolated from the foundations and foundation -supported
elements of the structure so that differential movement between the foundations and slab will not
induce excessive shear and bending stresses in the floor slab. Where the structural configuration
does not allow the use of a free-floating slab, the slab should be designed with adequate
reinforcement and load transfer devices to avoid overstressing of the slab.
4.2 SEISMIC DESIGN
The requires site classification for seismic design based on the upper 100 feet of a soil profile. Three
methods are utilized in classifying sites, namely the shear wave velocity (vs) method; the unconfined

Geotechnical Engineering Report— Davidson Charter Academy
ECS Project No. 09:28038-8
May 19, 2022
Page 9
compressive strength (s,,) method; and the Standard Penetration Resistance (N-value) method. The
N-value method was used for this project.
The seismic site class definitions for the weighted average of shear wave velocity or SPT N-value in
the upper 100 feet of the soil profile are shown in the following table:
Seismic Site Classification
Site
Class
Soil Profile Name
Shear Wave Velocity, Vs,
(ft./s)
N value (bpf)
A
Hard Rock
Vs > 5,000 fps
N/A
B
Rock
2,500 < Vs <- 5,000 fps
N/A
C
Very dense soil and soft rock
11200 < Vs <- 2,500 fps
>50
D
Stiff Soil Profile
600 <- Vs <- 1,200 fps
15 to 50
E
Soft Soil Profile
Vs < 600 fps
<15
The 2018 North Carolina Building requires that a Site Class be assigned for the seismic design of
new structures. The Site Class for the site was determined by calculating a weighted average SPT
N-value for the top 100 feet of the subsurface profile. Based on the conditions encountered in the
borings, we recommend that a Site Class "D" be used for design of the proposed building.
Our experience indicates that evaluation of seismic site class in North Carolina using N-values can
be overly conservative. If it is determined that significant advantage could be gained with an
improved Site Class, additional site testing could be performed to measure actual shear wave
velocities at the site. ECS can provide a proposal for these services upon request.
4.3 SITE DESIGN CONSIDERATIONS
4.3.1 Permanent Site Dewatering
Drainage Features: We recommend that French drains be installed in this area prior to filling. A
typical French drain would consist of an 18 to 24-inch wide by 18 to 24-inch tall bed of AASHTO Size
No. 57 Stone wrapped in a medium duty, non -woven filter fabric and containing a 6-inch diameter,
Schedule 40 PVC perforated pipe. Actual dimensions should be as determined necessary by ECS
during construction. However, the top of the drain should be positioned at least 18 inches below
design pavement subgrade elevations and a least 5 feet below design building subgrade elevations.
The French drains should be sloped at a minimum of 0.5% and should be daylighted to drain into
the site's permanent stormwater system at a structure or into a stormwater control measure.
4.3.2 Pavement Sections
Design Traffic Loading: Design traffic loading information for the pavements has not been provided
to us. Based on our experience with similar projects, we assume that the proposed private
pavements will be subjected to the average daily traffic, as given in the following table. This table
also provides our estimates for 20-year 18-kip Equivalent Single Axle Loads (ESALS) for the assumed
vehicle types and average daily traffic.

Geotechnical Engineering Report— Davidson Charter Academy
ECS Project No. 09:28038-8
Assumed Average Daily Traffic Loading
May 19, 2022
Page 10
Vehicle
Days
Per
Week
Light Duty
Pavement
Medium Duty
Pavement
Heavy Duty
Pavement
Passenger Cars
7
100
200
400
Pickups, Vans, SUVs
7
100
200
400
Buses
5
5
10
20
Garbage & Recycling Trucks
2
2
4
6
Dual Axle Trucks (NCDOT)
4
0
2
4
HS20, 80,000-lb, 18-wheel
Tractor -Trailer Truck with
tandem axles
7
0
0
2
20-year ESALs
28,000
58,350
144,500
The civil engineer, developer, owner, and/or user should verify these assumptions and notify ECS if
the actual pavement design traffic loading conditions exceed or are significantly less than these
assumed values. If the project will include any public pavements (NCDOT or local municipality), we
need the projected average daily traffic, % dual axle trucks, and % tractor trailer trucks in order to
provide recommended pavement sections for the public pavements.
Subgrade Characteristics: Pavement subgrades soils should consist of firm, stable, compacted low
plasticity soil. Elastic SILT (MH) should not be left in place or placed as fill immediately below the
pavements, or lime stabilization might be implemented. Based on our experience with similar soils,
a design CBR value of 4 is recommended for this project. The pavement design assumes subgrades
consist of suitable materials evaluated by ECS and placed and compacted to at least 98 percent of
the maximum dry density as determined by the Standard Proctor test (ASTM D 698).
Minimum Material Thicknesses: The following minimum pavement sections may be used by the
civil engineer to develop the pavement design drawings for the project, provided the civil engineer
is in agreement with ECS' design traffic loading assumptions and estimates. The contractor should
bid and construct the project in accordance with the civil design drawings, not the
recommendations given in this report. These recommendations are not contract drawings nor
specifications.
Asphalt Pavement Section Recommendations
Pavement
Light Duty
Medium Duty
Heavy Duty
Type
Material Designation
Pavement
Pavement
Pavement
(in.)
(in.)
(in)
Asphalt Surface Course (S9.513)
2.0
1.0
1.5
Flexible
Asphalt Intermediate Course (119.0C)
2.5
2.5
Aggregate Base Course
6.0
6.0
8.0

Geotechnical Engineering Report— Davidson Charter Academy
ECS Project No. 09:28038-8
Concrete Pavement Section Recommendations
Heavy Duty
Pavement
Material Designation
Concrete
Type
Pavement, Plain
Jointed (in.)
Portland Cement Concrete
6
(4000 psi, air -entrained)
Rigid
Aggregate Base Course
6
May 19, 2022
Page 11
Concrete Pavements: Concentrated front -wheel loads are frequently imposed on pavements in
trash dumpster and truck loading dock areas. This type of loading typically results in rutting and
scuffing of bituminous pavements and ultimately pavement failures and costly repairs. Therefore,
we recommend that the pavements in trash pickup and loading dock aprons areas utilize the
aforementioned Portland Cement Concrete (PCC) pavement section. It may be prudent to use rigid
pavement sections in all areas planned for heavy truck traffic.
The Portland cement concrete pavement section should consist of air -entrained Portland cement
concrete having a minimum 28-day compressive strength of 4,000 psi. The rigid pavement section
should be provided with construction joints and saw -cut control joints at appropriate intervals per
Portland Cement Association (PCA) requirements. The construction joints should be reinforced with
dowels to transfer loads across the joints. Wire mesh should be included to control shrinkage
cracking of the concrete.
The concrete pavement section thickness for plain jointed concrete pavement is with
reinforcement dowels only at construction joints.
Construction Traffic: It is important to note that the design sections do not account for
construction traffic loading. An incomplete pavement section without the final 1 inch of surface
course asphalt can be used for temporary construction traffic, such as concrete trucks and tractor
trailer material delivery trucks. Please note, however, that damage to the asphalt already placed is
likely to occur in localized areas, and it should be repaired by removal and replacement with new
asphalt at or near the end of construction, prior to placement of the surface course.
Alternatively, heavy construction vehicles and traffic should be limited to a temporary pavement
section consisting of 12 inches of compacted ABC overlying a high -strength woven geotextile
(Tencate Mirafi HP270 or equivalent). The temporary pavement section could then be graded and
covered with asphalt to achieve the final design heavy duty pavement section.
Public Streets/Roads: It should also be noted that these design recommendations may not satisfy
the local municipality or North Carolina Department of Transportation guidelines. Any roadways
constructed for public use and to be dedicated to the local municipality or State for repair and
maintenance must be designed in accordance with the local municipality or State requirements.
Drainage: An important consideration with the design and construction of pavements is surface
and subsurface drainage. Where standing water develops, either on the pavement surface or
within the aggregate base course layer, softening of the subgrades and other problems related to
the deterioration of the pavement can be expected. This is particularly important at the site due

Geotechnical Engineering Report— Davidson Charter Academy May 19, 2022
ECS Project No. 09:28038-8 Page 12
to the moisture sensitive near -surface soils. Furthermore, good drainage should help reduce the
possibility of the subgrade materials becoming saturated during the normal service period of the
pavement.
Minimum Material Thicknesses: Based on the anticipated traffic and subgrade characteristics, we
recommend the services roads consist of a minimum of 8 inches of compacted aggregate base
course (ABC) gravel. The aggregate base course should be compacted to at least 98 percent of
their modified Proctor maximum dry density (ASTM D 1557).
It should be noted that these design recommendations may not satisfy the North Carolina
Department of Transportation traffic guidelines. Any roadways constructed for public use and to
be dedicated to the State for repair and maintenance must be designed in accordance with the
State requirements.
5.0 SITE CONSTRUCTION RECOMMENDATIONS
5.1 SUBGRADE PREPARATION
5.1.1 Existing Utilities
Underground utilities are present at the site. Future access to existing utilities will be difficult if
covered by new construction. Existing utilities could be damaged by construction activity or by loads
from the new structures or pavements. Existing utilities left in place can trigger subsidence leading
to differential settlement and damage to new construction. Backfill associated with existing utilities
can cause variable support conditions as compared to the surrounding native soils. If existing or
former underground utilities are abandoned and not removed or grouted full, soil may migrate into
open voids (e.g., open pipes from utilities), causing subsidence of the overlying construction. In
addition, existing utility lines, if located within proposed construction areas, may cause the new
construction to behave unexpectedly due to the variable support conditions caused by old backfill.
Furthermore, old backfill along utility lines also may provide inadequate support due to poor
compaction. The poor support conditions may result in settlement or distress of the overlying new
construction. Based on our experience, existing utility backfill rarely is adequate for support of new
building foundations. In slab and pavement areas, the load support characteristics of the backfill
along utility lines typically can be assessed with careful proofrolling and subgrade evaluation during
construction. Some undercutting and/or bridging of these backfill areas should be anticipated.
5.1.2 Stripping and Grubbing
The subgrade preparation should consist of stripping vegetation, rootmat, topsoil, and other soft
or inadequate materials from the proposed construction areas. The borings generally encountered
1 to 2 inches of topsoil. The topsoil encountered in the borings was not analyzed for its adequacy
for reuse in landscaping areas. ECS should be called onto verify that topsoil and inadequate surficial
materials have been completely removed prior to the placement of engineered fill or construction
of structures and pavements.

Geotechnical Engineering Report— Davidson Charter Academy May 19, 2022
ECS Project No. 09:28038-8 Page 13
5.1.3 Proofrolling
After removing all unsuitable surface materials, cutting to the proposed grade, and prior to the
placement of any engineered fill or other construction materials, the exposed subgrade should be
examined by the geotechnical engineer or authorized representative. The exposed subgrade
should be thoroughly proofrolled with construction equipment having a minimum axle load of 10
tons (e.g. fully loaded tandem -axle dump truck). The areas subject to proofrolling should be
traversed by the equipment in two perpendicular (orthogonal) directions with overlapping passes
of the vehicle under the observation of the geotechnical engineer or authorized representative.
This procedure is intended to assist in identifying any localized yielding materials.
In the event that soft or "pumping" subgrade is identified by the proofrolling, those areas should
be marked for repair prior to the placement of subsequent engineered fill or other construction
materials. Methods of repair of poor subgrades, such as undercutting or moisture conditioning or
chemical stabilization, should be discussed with the geotechnical engineer to determine the
appropriate procedure with regard to the existing conditions causing the instability.
Based on the soil test borings, we anticipate limited undercutting of very soft to soft or very loose
near -surface natural soils will be necessary in localized areas of the site. Based on the near surface
N-value at boring B-05, we anticipate that the proofroll will yield unstable soils in the vicinity that
will require remediation prior to fill placement. If site earthwork is performed during the typically
cooler, wetter months of the year, additional undercutting in other areas of the site is anticipated
due to potentially excessively wet inadequate soils. Undercut excavations should be backfilled with
properly placed and engineered fill. Use of geotextiles and select granular fill maybe recommended
by ECS during construction to reduce the required undercut depths and/or aid in stabilization of
subgrades. We recommend that inadequate soils undercut allowance quantities be determined by
the design team for inclusion in a classified earthwork contract, and bidders should provide unit
prices for the following:
• Excavation of, disposal of (either off -site or on -site, depending on available space and
owner's preference), and replacement of inadequate soils with engineered fill (per cubic
yard).
• Excavation of, disposal of (either off -site or on -site, depending on available space and
owner's preference), and replacement of inadequate soils with NCDOT Class II, Type 1
Select Material (per cubic yard).
• Installation of woven geotextile, Mirafi HP270 or equivalent (per square yard)
5.2 EARTHWORK OPERATIONS
5.2.1 Expansive Soil
Elastic SILT (MH) soils are present in some Borings in localized areas at the site. These are potentially
expansive soils per the current North Carolina Building Code and local practice. However, based on
the laboratory test results, these soils have a low potential for expansion (i.e., shrink -swell). We
estimate that the potential heave of footings, floor slabs, and pavements due to potential wetting
and settlement due to drying of potentially expansive soils will be less than 1 inch. As such, no

Geotechnical Engineering Report— Davidson Charter Academy May 19, 2022
ECS Project No. 09:28038-8 Page 14
specific mitigation measures for footings, floor slabs due to potentially expansive soils are
recommended.
Even though the on -site Elastic SILT (MH) is very moisture sensitive and can be relatively weak and
compressible. The moisture contents will require careful control and must be within +/- 3% of the
soil's standard Proctor maximum dry density to provide stability and to reduce excessive swell
heave, shrinkage settlement, or collapse settlement.
5.2.2 Excavation Considerations
Excavation Safety: Excavations and slopes should be made and maintained in accordance with
OSHA excavation safety standards. The contractor is solely responsible for designing and
constructing firm, temporary excavations and slopes and should shore, slope, or bench the sides of
the excavations and slopes as required to maintain stability of both the excavation sides and
bottom. The contractor's responsible person, as defined in 29 CFR Part 1926, should evaluate the
soil exposed in the excavations as part of the contractor's safety procedures. In no case should
slope height, slope inclination, or excavation depth, including utility trench excavation depth,
exceed those specified in local, state, and federal safety regulations. ECS is providing this
information solely as a service to our client. ECS is not assuming responsibility for construction site
safety or the contractor's activities; such responsibility is not being implied and should not be
inferred.
Construction Dewatering: Based on the borings, our experience with groundwater fluctuations on
similar sites, and anticipated design grades, most of the temporary excavations are unlikely to
encounter groundwater. The contractor should be prepared to remove precipitation or
groundwater that may seep into temporary construction excavations using open pumping. Open
pumping utilizes submersible sump pumps in pits or trenches dug below the bottom of the
excavation and backfilled with No. 57 stone.
Excavatibility: Based on the estimated excavation depths for mass grading, footings and utilities,
we anticipate that the majority of the materials to be excavated will be natural soils, which can be
removed with conventional earth excavation equipment such as track -mounted backhoes, loaders,
or bulldozers. However, the weathering process in the Piedmont can be erratic and significant
variations of the depths of the more dense materials can occur in relatively short distances. In some
cases, isolated boulders or thin rock seams may be present in the soil matrix.
5.2.3 Structural Fill Materials
Product Submittals: At least one week prior to placement of structural fill, representative bulk
samples (about 50 pounds) of on -site and/or off -site borrow should be submitted to ECS for
laboratory testing, which will include Atterberg limits, natural moisture content, grain -size
distribution, and moisture -density relationships for compaction. Import materials should be tested
prior to being hauled to the site to determine if they meet project specifications.
Satisfactory Structural Fill Materials: Materials satisfactory for use as structural fill should consist
of inorganic soils classified as CL, MIL, SM, SC, SW, SP, GW, GM and GC, or a combination of these
group symbols, per ASTM D 2487. The materials should be free of organic matter and debris. The
fill should exhibit a maximum dry density of at least 90 pounds per cubic foot, as determined by a

Geotechnical Engineering Report— Davidson Charter Academy May 19, 2022
ECS Project No. 09:28038-8 Page 15
Standard Proctor compaction test (ASTM D 698). Since the on -site Elastic SILT (MH) has a low
expansion potential, it may be placed as structural fill for mass grading.
Unsatisfactory Materials: Unsatisfactory fill materials include materials which do not satisfy the
requirements for satisfactory materials, such as topsoil, organic materials, debris, and debris -laden
fill.
On -Site Borrow Suitability: The on -site soils meeting the classifications for recommended
satisfactory structural fill, plus meeting the restrictions on separation distances, organic content,
and debris, may be used as structural fill. We anticipate that most of the soils encountered in the
borings within the anticipated excavation depths will be satisfactory for use as compacted
structural fill.
Soils with less than 3% organics are termed mineral soils and those with 3% to 15% organics are
classified as mineral soils with organics'. The NCDOT defines silts and clays with at least 5% organic
content and sands with at least 3% organic content as organic soil', and may reject borrow soil with
an organic content of more than 4% 3.
On -site soils used as structural fill will require careful moisture control in order to achieve
compaction and stability. Soils excavated from below the water table will require significant drying
to achieve the recommended moisture content and minimum compaction. Soils above the water
table may also be relatively dry at the time of construction and require wetting to achieve the
recommended moisture content and minimum compaction.
5.2.4 Compaction
Fill Compaction: Structural fill should be placed in maximum 8-inch loose lifts. In confined areas
such as utility trenches, portable compaction equipment and thin lifts of 4 inches to 6 inches may
be required to achieve specified degrees of compaction.
Structural fill should be moisture conditioned as necessary to within -3 and +3 % of the soil's
optimum moisture content. Moisture conditioning options include spraying and mixing in water to
excessively dry soils, scarifying and drying of excessively wet soils, and adding lime to excessively
wet soils.
Structural fill should be compacted with adequate equipment to a dry density of at least 95% of the
Standard Proctor maximum dry density (ASTM D698) more than 12 inches below the finish
subgrade elevation and to a least 98% in the upper 12 inches.
ECS should be retained to observe and test the placement and compaction of structural fill.
1 Huang et. al. (2009), Classification of Organic Soils, Report No. FHWA/IN/JTRP-2008/2, prepared in cooperation with the
Indiana Department of Transportation and the Federal Highway Administration.
z NCDOT Geotechnical Investigation and Recommendations Manual, dated March 29, 2016, Section
3 NCDOT 2018 Standard Specifications for Roads and Structures, Section 1018.2 (B) (3).

Geotechnical Engineering Report— Davidson Charter Academy May 19, 2022
ECS Project No. 09:28038-8 Page 16
Fill Placement Considerations: Proper drainage should be maintained during the earthwork phases
of construction to reduce the likelihood of ponding of water which will degrade the subgrade soils.
Exposed soil subgrades should be protected at the end of each working day by sloping to drain and
sealing with a smooth -drum roller to limit infiltration of precipitation and surface water. Where fill
materials will be placed to widen existing embankment fills, or placed up against sloping ground,
the soil subgrade should be scarified and the new fill benched or keyed into the existing material.
Fill material should be placed in horizontal lifts.
Moisture Conditioning: The on -site soils are moisture sensitive and can be difficult to work.
Problems include softening of exposed subgrade soils, excessive rutting or deflection under
construction traffic, and the inability to adequately dry and compact wet soil.
Drying and compaction of wet soils is typically difficult during typically cooler, wetter months of the
year (typically November through March). During the cooler and wetter periods of the year, delays
and additional costs should be anticipated. At these times, reduction of soil moisture may need to
be accomplished by a combination of mechanical manipulation and the use of chemical additives,
such as lime or cement, in order to lower moisture contents to levels appropriate for compaction.
Alternatively, removal and replacement with drier, off -site materials may be necessary.
Subgrade Protection: Measures should also be taken to limit site disturbance, especially from
rubber -tired heavy construction equipment, and to control and remove surface water from
development areas, including structural and pavement areas. It would be advisable to designate
and cover haul roads and construction staging areas to limit the areas of disturbance and to reduce
construction traffic from excessively degrading subgrade soils. Haul roads and construction staging
areas should be covered with ABC to protect those subgrades.
5.3 FOUNDATIONS AND FLOOR SLABS
Protection of Foundation Excavations: Exposure to the environment may weaken the soils at the
footing bearing level if the foundation excavations remain open for too long a time. Therefore,
foundation concrete should be placed the same day that excavations are made or shortly
thereafter. If the bearing soils are softened by surface water intrusion or exposure, the softened
soils must be removed from the foundation excavation bottom immediately prior to placement of
concrete. If the excavation must remain open overnight, or if rainfall becomes imminent while the
bearing soils are exposed, a 1 to 3-inch thick "mud mat" of "lean" concrete should be placed on the
bearing soils before the placement of reinforcing steel.
Footing Subgrade Observations: It will be important to have the geotechnical engineer of record
observe the foundation subgrade prior to placing foundation concrete, to confirm the bearing soils
are as anticipated.
If very loose sand, very soft to soft silt/clay, or otherwise unsuitable or unstable soils are observed
at the footing bearing elevations, they should be undercut and removed. Any undercut excavation
should be backfilled with compacted structural fill, No. 57 stone wrapped in woven geotextile,
flowable fill, or lean concrete (Fc >— 1,000 psi at 28 days) up to the original design bottom of footing
elevation. The footing should be constructed on top of the compacted structural fill, No. 57 stone
wrapped in woven geotextile, hardened flowable fill, or hardened lean concrete.

Geotechnical Engineering Report— Davidson Charter Academy May 19, 2022
ECS Project No. 09:28038-8 Page 17
Slab Subgrade Verification: A representative of ECS should be called on to observe exposed
subgrades within the expanded building limits prior to structural fill placement to assure that
adequate subgrade preparation has been achieved. Proofrolling using a drum roller or loaded
dump truck should be performed in their presence at that time. Once subgrades have been
determined to be firm and stable, structural fill can be placed.
If there will be a significant time lag between the site grading work and final grading of concrete
slab areas prior to the placement of the design floor slab section materials, a representative of ECS
should be called on to verify the condition of the prepared soil subgrade. Prior to final floor slab
section construction, the soil subgrade may require scarification, moisture conditioning, and re -
compaction to restore stable conditions.
5.4 PAVEMENTS
5.4.1 Subgrade Evaluation
The soil subgrade should be smooth -rolled and proofrolled prior to ABC placement. Areas that
pump, rut, or are otherwise inadequate should be re -compacted or undercut and replaced. Based
on the borings, we anticipate undercutting of very soft to soft or very loose pavement subgrade
soils could be necessary in localized areas of the site. The amount of undercutting will be
dependent on design grades and weather conditions at the time of construction.
5.4.2 Aggregate Base Course
The ABC should conform with the gradation, liquid limit, plasticity index, resistance to abrasion, and
soundness per Section 1005 of the 2012 NCDOT Standard Specifications for Roads and Structures.
It should be spread after end -dumping on previously -placed ABC to reduce rutting and degradation
of the relatively clean sand subgrade soils by rubber -tired dump trucks. The relatively clean sand
subgrade soils should be wetted if dry of the optimum moisture content and rolled with a vibratory
smooth -drum roller immediately prior to ABC placement.
The ABC should be placed and be compacted in accordance with Section 520 of the 2012 NCDOT
Standard Specifications for Roads and Structures. The ABC should be placed in a single lift if 10
inches or less in thickness. Two lifts of ABC should be placed for layers more than 10 inches thick.
The ABC should be compacted to at least 98 percent of its Modified Proctor maximum dry unit
weight per ASTM D1557 or AASHTO T180 (as modified by NCDOT), provided nuclear density testing
is performed. Otherwise, at least 100 percent compaction is recommended.
To confirm that the specified degree of compaction is being obtained, field compaction testing
should be performed in each ABC lift by the geotechnical engineer's representative. We
recommend that compaction tests be performed at a minimum frequency of one test per 5,000
square feet per lift in pavement areas.
The early placement of the ABC will minimize the deterioration of the prepared soil subgrades.
However, some loss of graded aggregate due to rutting and surface contamination may occur prior
to final asphalt or concrete paving. Some infilling and re -grading of the aggregate base course may

Geotechnical Engineering Report— Davidson Charter Academy May 19, 2022
ECS Project No. 09:28038-8 Page 18
be required. The ABC should be smooth -rolled and proofrolled prior to asphalt or concrete
pavement placement. Areas that pump, rut, or are otherwise inadequate should be wetted or dried
as needed and re -compacted. Alternatively, inadequate areas could be undercut and replaced.
5.4.3 Asphalt Pavement Construction
Minimum Asphalt Lift Thickness: The minimum lift thickness for S9.5B is 1.0 inch and the maximum
lift thickness for S9.5B is 1.5 inches. For sections with more than 1.5 inches of S9.5B surface
asphalt, it should be placed in two lifts. Asphalt pavement S9.5B should be compacted to least 90.0
percent of the material's specific gravity Gmm.
Asphalt Quality Control/Quality Assurance: We recommend that the asphalt contractor perform
quality control procedures and testing per the project specifications to establish the required roller
pattern(s). Quality assurance testing should be provided by the geotechnical engineer's
representative and should consist of coring the placed asphalt pavement to verify thickness and
compaction.
5.5 UTILITY INSTALLATIONS
Utility Subgrades: The soils encountered in our exploration are expected to be generally adequate
for support of utility pipes. The pipe subgrades should be observed and probed for stability by ECS.
Loose or inadequate materials encountered should be removed and replaced with adequately
compacted structural fill, or pipe stone bedding material.
Utility Backfilling: We recommend that the bedding materials be placed up to the springline of the
pipe. Fill placed for support of the utilities, as well as backfill over the utilities, should satisfy the
requirements for structural fill and fill placement.
The pipe, manholes, and wet wells should bear on 8 to 12 inches of No. 57 stone, as shown on the
project drawing details. Poor subgrade conditions for the sewer pipe (very loose sands, very soft
to soft clays) were encountered at some of the boring locations. Some undercutting and
replacement of inadequate soils may be required.
The contractor's excavation temporary sloping/shoring and dewatering designs should account for
the recommended and potential undercut depth below the bottom of the pipe and manholes.
5.6 GENERAL CONSTRUCTION CONSIDERATIONS
Surface Drainage: Surface drainage conditions should be properly maintained. Surface water
should be directed away from the construction area, and the work area should be sloped away from
the construction area at a gradient of 1 percent or greater to reduce the potential of ponding water
and the subsequent saturation of the surface soils. At the end of each work day, the subgrade soils
should be sealed by rolling the surface with a smooth drum roller to reduce the likelihood of the
infiltration of surface water.
Excavation Safety: Cuts or excavations associated with utility excavations may require forming or
bracing, slope flattening, or other physical measures to control sloughing and/or prevent slope

Geotechnical Engineering Report— Davidson Charter Academy May 19, 2022
ECS Project No. 09:28038-8 Page 19
failures. Contractors should be familiar with applicable OSHA codes to ensure that adequate
protection of the excavations and trench walls is provided.
Erosion Control: The surface soils may be erodible. Therefore, the Contractor should provide and
maintain good site drainage during earthwork operations to maintain the integrity of the surface
soils. Erosion and sedimentation controls should be in accordance with sound engineering
practices and local requirements.
6 CLOSING
ECS has prepared this report of findings, evaluations, and recommendations to guide geotechnical-
related design and construction aspects of the project.
The description of the proposed project is based on information provided to ECS. If this information
is inaccurate, either due to our interpretation of the documents provided or site or design changes
that may occur later, ECS should be contacted immediately in order that we can review the report
in light of the changes and provide additional or alternate recommendations as may be required to
reflect the proposed construction.
We recommend that ECS be allowed to review the project's plans and specifications pertaining to
our work so that we may ascertain consistency of those plans/specifications with the intent of the
geotechnical report.
Field observations, monitoring, and quality assurance testing during earthwork and foundation
installation are an extension of and integral to the geotechnical design recommendation. We
recommend that the owner retain these quality assurance services and that ECS be allowed to
continue our involvement throughout these critical phases of construction to provide general
consultation as issues arise. ECS is not responsible for the conclusions, opinions, or
recommendations of others based on the data in this report.

APPENDIX A — Diagrams
Site Location Diagram
Boring Location Diagram
Cross Section Location Diagram

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ii
Zack (ar ,•�,+";`>�'`� .
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,
r
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APPENDIX B — Field Operations
Reference Notes for Boring Logs
Subsurface Exploration Procedure: Standard Penetration Testing (SPT)
Boring Logs
Generalized Subsurface Soils Profiles

ECS
MATERIAL
REFERENCE NOTES FOR BORING LOGS
ASPHALT
CONCRETE
GRAVEL
TOPSOIL
VOID
BRICK
AGGREGATE BASE COURSE
GW
GP
GM
GC
SW
SP
SM
SC
ML
MH
CL
CH
OL
WELL -GRADED GRAVEL
gravel -sand mixtures, little or no fines
POORLY -GRADED GRAVEL I
gravel -sand mixtures, little or no fines
SILTY GRAVEL
gravel -sand -silt mixtures
CLAYEY GRAVEL
gravel -sand -clay mixtures
WELL -GRADED SAND
gravelly sand, little or no fines
POORLY -GRADED SAND
gravelly sand, little or no fines
SILTY SAND
sand -silt mixtures
CLAYEY SAND
sand -clay mixtures
SILT
non -plastic to medium plasticity
ELASTIC SILT
high plasticity
LEAN CLAY
low to medium plasticity
FAT CLAY
high plasticity
ORGANIC SILT or CLAY
non -plastic to low plasticity
DRILLING SAMPLING SYMBOLS & ABBREVIATIONS
SS
Split Spoon Sampler
PM
Pressuremeter Test
ST
Shelby Tube Sampler
RD
Rock Bit Drilling
WS
Wash Sample
RC
Rock Core, NX, BX, AX
BS
Bulk Sample of Cuttings
REC
Rock Sample Recovery %
PA
Power Auger (no sample)
RQD
Rock Quality Designation %
HSA Hollow Stem Auger
PARTICLE SIZE IDENTIFICATION
DESIGNATION
PARTICLE SIZES
Boulders
12 inches (300 mm) or larger
Cobbles
3 inches to 12 inches (75 mm to 300 mm)
Gravel: Coarse
% inch to 3 inches (19 mm to 75 mm)
Fine
4.75 mm to 19 mm (No. 4 sieve to % inch)
Sand: Coarse
2.00 mm to 4.75 mm (No. 10 to No. 4 sieve)
Medium
0.425 mm to 2.00 mm (No. 40 to No. 10 sieve)
Fine
0.074 mm to 0.425 mm (No. 200 to No. 40 sieve)
Silt & Clay ("Fines")
<0.074 mm (smaller than a No. 200 sieve)
COHESIVE SILTS & CLAYS
UNCONFINED
COMPRESSIVE
SPT5
CONSISTENCY'
STRENGTH, QP°
(BPF)
(COHESIVE)
<0.25
<2
Very Soft
0.25 - <0.50
3-4
Soft
0.50 - <1.00
5-8
Firm
1.00 - <2.00
9 - 15
Stiff
2.00 - <4.00
16 - 30
Very Stiff
4.00 - 8.00
31 - 50
Hard
>8.00
>50
Very Hard
GRAVELS, SANDS & NON -COHESIVE SILTS
arl
DENSITY
<5
Very Loose
5-10
Loose
11 - 30
Medium Dense
31 - 50
Dense
>50
Very Dense
RELATIVE
AMOUNT
COARSE
GRAINED
(%)8
FINE
GRAINED
(%)8
Trace
<5
<5
With
10 - 20
10 - 25
Adjective
25 - 45
30 - 45
(ex: "Silty')
WATER LEVELS6
V
WL (First Encountered)
WL (Completion)
WL (Seasonal High Water)
WL (Stabilized)
OH ORGANIC SILT or CLAY FILL AND ROCK
high plasticity
PT PEAT
highly organic soils
FILL POSSIBLE FILL PROBABLE FILL ROCK
'Classifications and symbols per ASTM D 2488-17 (Visual -Manual Procedure) unless noted otherwise.
2To be consistent with general practice, "POORLY GRADED" has been removed from GP, GP -GM, GP -GC, SP, SP-SM, SP-SC soil types on the boring logs.
3Non-ASTM designations are included in soil descriptions and symbols along with ASTM symbol [Ex: (SM-FILL)].
4Typically estimated via pocket penetrometer or Torvane shear test and expressed in tons per square foot (tsf).
5Standard Penetration Test (SPT) refers to the number of hammer blows (blow count) of a 140 lb. hammer falling 30 inches on a 2 inch OD split spoon sampler
required to drive the sampler 12 inches (ASTM D 1586). "N-value" is another term for "blow count' and is expressed in blows per foot (bpf). SPT correlations per 7.4.2 Method B
and need to be corrected if using an auto hammer.
6The water levels are those levels actually measured in the borehole at the times indicated by the symbol. The measurements are relatively reliable
when augering, without adding fluids, in granular soils. In clay and cohesive silts, the determination of water levels may require several days for the
water level to stabilize. In such cases, additional methods of measurement are generally employed.
Minor deviation from ASTM D 2488-17 Note 14.
8Percentages are estimated to the nearest 5% per ASTM D 2488-17.
Reference Notes for Boring Logs (0324-2021).doc © 2021 ECS Corporate Services, LLC. All Rights Reserved

SUBSURFACE EXPLORATION PROCEDURE:
STANDARD PENETRATION TESTING (SPT)
ASTM D 1586
Split -Barrel Sampling
Standard Penetration Testing, or SPT, is the most frequently used
subsurface exploration test performed worldwide. This test provides
samples for identification purposes, as well as a measure of penetration
resistance, or N-value. The N-Value, or blow counts, when corrected and
correlated, can approximate engineering properties of soils used for
geotechnical design and engineering purposes.
• Involves driving a hollow tube (split -spoon)
into the ground by dropping a 140-lb hammer
a height of 30-inches at desired depth
• Recording the number of hammer blows re-
quired to drive split -spoon a distance of 12
inches (in 3 or 4 Increments of 6 inches each)
• Auger is advanced* and an additional SPT is
performed
• One SPT testis typically performed for every
two to five feet
• Obtain two-inch diameter soil sample
*Drilling Methods May Vary— The predominant drilling
methods used for SPT are open hole fluid rotary drilling and
hollow -stem auger drilling.

CLIENT:
Bradley & Ball Architects, PA
PROJECT NO.:
09:28038-B
BORING NO.:
B-01
SHEET:
1 of 1
PROJECT NAME:
DRILLER/CONTRACTOR:
Davidson Charter Academy - Geo
M & M Drilling
SITE LOCATION:
Biesecker Road, Lexington, North Carolina 27292
LOSS oFCIRCULATION
iaaz
NORTHING:
EASTING:
STATION:
SURFACE ELEVATION:
eorroM of CASING765239.7
'
1623326.7
774
C
--
Plastic Limit Water Content Liquid Limit
Co
w
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x o
B-
}
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J
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\
®STANDARD PENETRATION BLOWS/ET
=
F
z
a
w
DESCRIPTION OF MATERIAL
ROCK QUALITY DESIGNATION&RECOVERY
w
J
a
<
J
a
V
Q
j
ROD
Q
v7
Q
Zi
w
Co
_ REC
O CALIBRATED PENETROMETER TON/SF
[FINES CONTENT] %
Topsoil Thickness[1.00"]
6-5-6
(ML) Residuum, SILT, trace organics,
S-1
SS
18
14
contains mica, brown, red and orange,
(11)
moist, stiff to hard
4-7-10
(17)
,,
S-2
SS
18
18
5
769
7-11-15
(26)
6
S-3
SS
18
18
8-14-20
(34)
4
S-4
SS
18
18
10
764
5-10-13
(23)
s
S-5
SS
18
18
15
759
(ML) SANDY SILT, contains mica, gray,
orange and yellow, wet, very stiff
5-9-10
(19)
19
S-6
SS
18
16
20
754
(SM) SILTY SAND, contains mica, dark
gray and brown, wet, loose
S-7
SS
18
3
3-4-4
($)
a
25
749
END OF BORING AT 26 FT
30
744
THE STRATIFICATION LINES REPRESENT THE APPROXIMATE BOUNDARY LINES BETWEEN SOIL TYPES. IN -SITU THE TRANSITION MAY BE GRADUAL
SZ WL (First Encountered) Dry
BORING STARTED: May 042022
CAVE IN DEPTH: 11.68
1 WL (Completion) Dry
BORING May 042022
COMPLETED:
HAMMER TYPE:
7 WL (Seasonal High Water)
EQUIPMENT: LOGGED
Truck �MAA7
BY:
DRILLING METHOD:2.25H.5.A
SZ WL (Stabilized)
GEOTECHNICAL BOREHOLE LOG

CLIENT:
Bradley & Ball Architects, PA
PROJECT NO.:
09:28038-B
BORING NO.:
B-02
SHEET:
1 of 1
PROJECT NAME:
DRILLER/CONTRACTOR:
Davidson Charter Academy - Geo
M & M Drilling
SITE LOCATION:
Biesecker Road, Lexington, North Carolina 27292
LOSS oFCIRCULATION
iaaz
NORTHING:
EASTING:
STATION:
SURFACE ELEVATION:
eorroM of CASING765236.0
'
1623493.6
782
C
--
Plastic Limit Water Content Liquid Limit
Co
w
z
z
x o
B-
}
w
J
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\
®STANDARD PENETRATION BLOWS/ET
=
F
z
a
w
DESCRIPTION OF MATERIAL
ROCK QUALITY DESIGNATION&RECOVERY
w
J
a
<
J
a
V
Q
j
ROD
Q
v7
Q
Zi
w
Co
_ REC
O CALIBRATED PENETROMETER TON/SF
[FINES CONTENT] %
Topsoil Thickness[1.00"]
4-5-7
(ML) Residuum, SILT, contains mica,
S 1
SS
18
12
brown, red and yellow, moist, stiff to
(12)
33`/ 4�
z .24'0 [65.9r]
very stiff
5-10-13
(23)
3
S-2
SS
18
18
5
777
6-10-15
(25)
2e
S-3
SS
18
18
6-12-15
(27)
S-4
SS
18
18
10
772
6-9-12
(21)
21
S-5
SS
18
18
15
767
(ML) SANDY SILT, contains mica and rock
fragments, brown, orange and gray, wet,
stiff
S-6
SS
18
18
3-6-8
(14)
14
20
762
(SM) SILTY SAND, trace organics, contains
mica, gray and brown, wet, medium
S-7
SS
18
18
dense
(14)
(14)
1u
25
757
END OF BORING AT 26 FT
30
752
THE STRATIFICATION LINES REPRESENT THE APPROXIMATE BOUNDARY LINES BETWEEN SOIL TYPES. IN -SITU THE TRANSITION MAY BE GRADUAL
SZ WL (First Encountered) Dry
BORING STARTED: May 042022
CAVE IN DEPTH: 12.70
1 WL (Completion) Dry
BORING May 042022
COMPLETED:
HAMMER TYPE:
7 WL (Seasonal High Water)
EQUIPMENT: LOGGED
Truck �MAA7
BY:
DRILLING METHOD:2.25H.5.A.
SZ WL (Stabilized)
GEOTECHNICAL BOREHOLE LOG

CLIENT:
Bradley & Ball Architects, PA
PROJECT NO.:
09:28038-B
BORING NO.:
B-03
SHEET:
1 of 1
PROJECT NAME:
DRILLER/CONTRACTOR:
Davidson Charter Academy - Geo
M & M Drilling
SITE LOCATION:
Biesecker Road, Lexington, North Carolina 27292
LOSS oFCIRCULATION
iaaz
NORTHING:
EASTING:
STATION:
SURFACE ELEVATION:
eorroM of CASING765215.6
'
1623601.4
786
C
--
Plastic Limit Water Content Liquid Limit
Co
w
z
z
x o
B-
}
w
J
Z
\
®STANDARD PENETRATION BLOWS/ET
=
F
z
a
w
DESCRIPTION OF MATERIAL
ROCK QUALITY DESIGNATION&RECOVERY
w
J
a
<
J
a
V
Q
j
ROD
Q
v7
Q
Zi
w
Co
_ REC
O CALIBRATED PENETROMETER TON/SF
[FINES CONTENT] %
Topsoil Thickness[1.00"]
6-6-6
(ML) Residuum, SILT, contains mica, red,
S-1
SS
18
15
gray and dark brown, moist to wet, stiff
(12)
12
to very stiff
5-8-14
(22)
2
S-2
SS
18
18
5
781
6-11-12
(23)
3
S-3
SS
18
18
6-10-14
(24)
24
S-4
SS
18
18
10
776
4-6-8
(14)
14
S-5
SS
18
18
15
771
(ML) SANDY SILT, trace organics, contains
mica, gray and brown, wet, stiff
3-5-5
(10)
,D
S-6
SS
18
18
20
766
(SM) SILTY SAND, trace organics, contains
mica, gray and brown, wet, loose
S-7
SS
18
18
3-4-5
(9)
s
25
761
END OF BORING AT 26 FT
30
756
THE STRATIFICATION LINES REPRESENTTHE APPROXIMATE BOUNDARY LINES BETWEEN SOIL TYPES. IN -SITU THE TRANSITION MAY BE GRADUAL
SZ WL (First Encountered) Dry
BORING STARTED: May 042022
CAVE IN DEPTH: 13.25
1 WL (Completion) Dry
BORING May 042022
COMPLETED:
HAMMER TYPE:
7 WL (Seasonal High Water)
EQUIPMENT: LOGGED
Truck �MAA7
BY:
DRILLING METHOD:2.25H.5.A.
SZ WL (Stabilized)
GEOTECHNICAL BOREHOLE LOG

CLIENT:
Bradley & Ball Architects, PA
PROJECT NO.:
09:28038-B
BORING NO.:
B-04
SHEET:
1 of 1
PROJECT NAME:
DRILLER/CONTRACTOR:
Davidson Charter Academy - Geo
M & M Drilling
SITE LOCATION:
Biesecker Road, Lexington, North Carolina 27292
LOSS oFCIRCULATION
iaaz
NORTHING:
EASTING:
STATION:
SURFACE ELEVATION:
eorroM of CASING765132.0
'
1623328.5
780
C
--
Plastic Limit Water Content Liquid Limit
Co
w
z
z
x o
B-
}
w
J
Z
\
®STANDARD PENETRATION BLOWS/ET
=
F
z
a
w
DESCRIPTION OF MATERIAL
ROCK QUALITY DESIGNATION&RECOVERY
w
J
a
<
J
a
V
Q
j
ROD
Q
v7
Q
Zi
w
Co
_ REC
O CALIBRATED PENETROMETER TON/SF
[FINES CONTENT] %
Topsoil Thickness[2.00"]
4-5-7
(ML) Residuum, SILT, contains mica, red,
S-1
SS
18
15
brown and gray, moist, stiff to very stiff
(12)
12
5-10-18
(28)
28
S-2
SS
18
18
5
775
6-13-16
(29)
s
S-3
SS
18
18
5-10-15
(25)
2e
S-4
SS
18
18
10
770
4-7-11
(18)
18
S-5
SS
18
18
15
765
(ML) SANDY SILT, trace organics, contains
mica, gray, brown and black, moist to
wet, stiff
S-6
SS
18
16
4-5-6
(11)
20
760
(SM) SILTY SAND, contains mica, gray and
brown, wet, loose
S-7
SS
18
18
3-4-5
(9)
s
25
755
END OF BORING AT 26 FT
30
750
THE STRATIFICATION LINES REPRESENT THE APPROXIMATE BOUNDARY LINES BETWEEN SOIL TYPES. IN -SITU THE TRANSITION MAY BE GRADUAL
SZ WL (First Encountered) Dry
BORING STARTED: May 042022
CAVE IN DEPTH: 15.80
1 WL (Completion) Dry
BORING May 042022
COMPLETED:
HAMMER TYPE:
7 WL (Seasonal High Water)
EQUIPMENT: LOGGED
Truck MAA7
BY:
DRILLING METHOD: 2.25H.5.A.
SZ WL (Stabilized)
GEOTECHNICAL BOREHOLE LOG

CLIENT:
Bradley & Ball Architects, PA
PROJECT NO.:
09:28038-B
BORING NO.:
B-05
SHEET:
1 of 2
PROJECT NAME:
DRILLER/CONTRACTOR:
Davidson Charter Academy - Geo
M & M Drilling
SITE LOCATION:
Biesecker Road, Lexington, North Carolina 27292
LOSS oFCIRCULATION
iaaz
NORTHING:
EASTING:
STATION:
SURFACE ELEVATION:
eorroM of CASING765130.0
'
1623487.4
785
C
--
Plastic Limit Water Content Liquid Limit
Co
w
z
z
x o
B-
}
w
J
Z
\
®STANDARD PENETRATION BLOWS/ET
=
F
z
a
w
DESCRIPTION OF MATERIAL
ROCK QUALITY DESIGNATION&RECOVERY
w
J
a
<
J
a
V
Q
j
ROD
Q
Q
w
Co
- REC
O CALIBRATED PENETROMETER TON/SF
[FINES CONTENT] %
Topsoil Thickness[1.00"]
3-2-3
(ML) Residuum, SILT, contains mica, red
S-1
SS
18
18
and brown, moist, soft to very stiff
(5)
30 4
21!.10 [6910%]
8-14-16
(30)
o
S-2
SS
18
18
5
780
6-10-13
(23)
3
S-3
SS
18
18
4-8-11
(19)
9
S-4
SS
18
18
10
775
(ML) SANDY SILT, contains mica, gray,
black and brown, moist to wet, very stiff
4-4-4
S-5
SS
18
18
($)
s
15
770
(SM) Residuum, SILTY SAND, contains
mica, brown and gray, wet, loose to
medium dense
S-6
SS
18
16
1-2-2
(4)
a
20
:::
765
1-2-2
(4)
4
S-7
SS
18
18
25
760
2-3-3
(6)
g
S-8
SS
18
10
30
755
CONTINUED ON NEXT PAGE
THE STRATIFICATION LINES REPRESENTTHE APPROXIMATE BOUNDARY LINES BETWEEN SOIL TYPES. IN -SITU THE TRANSITION MAY BE GRADUAL
SZ WL (First Encountered) Dry
BORING STARTED: May 042022
CAVE IN DEPTH: 17.00
1 WL (Completion) Dry
BORING May 042022
COMPLETED:
HAMMER TYPE:
7 WL (Seasonal High Water)
EQUIPMENT: LOGGED
Truck MAA7
BY:
DRILLING METHOD: 2.25H.5.A.
SZ WL (Stabilized)
GEOTECHNICAL BOREHOLE LOG

CLIENT:
Bradley & Ball Architects, PA
PROJECT NO.:
09:28038-B
BORING NO.:
B-05
SHEET:
2 of 2
PROJECT NAME:
DRILLER/CONTRACTOR:
Davidson Charter Academy - Geo
M & M Drilling
SITE LOCATION:
Biesecker Road, Lexington, North Carolina 27292
LOSS oFCIRCULATION
iaaz
NORTHING:
EASTING:
STATION:
SURFACE ELEVATION:
eorroM of CASING765130.0
'
1623487.4
785
C
--
Plastic Limit Water Content Liquid Limit
Co
w
z
z
x o
B-
}
w
J
Z
\
®STANDARD PENETRATION BLOWS/ET
=
F
z
a
w
DESCRIPTION OF MATERIAL
ROCK QUALITY DESIGNATION&RECOVERY
w
J
a
<
J
a
V
Q
j
ROD
Q
v7
Q
Zi
w
Co
_ REC
O CALIBRATED PENETROMETER TON/SF
[FINES CONTENT] %
(SM) Residuum, SILTY SAND, contains
mica, brown and gray, wet, loose to
medium dense
3-4-5
I91
s
S-9
SS
18
11
35
750
3-5-6
S-10
SS
18
10
40
745
END OF BORING AT 40 FT
45
740
50
735
55
730
60
725
THE STRATIFICATION LINES REPRESENT THE APPROXIMATE BOUNDARY LINES BETWEEN SOIL TYPES. IN -SITU THE TRANSITION MAY BE GRADUAL
SZ WL (First Encountered) Dry
BORING STARTED: May 042022
CAVE IN DEPTH: 17.00
1 WL (Completion) Dry
BORING May 042022
COMPLETED:
HAMMER TYPE:
7 WL (Seasonal High Water)
EQUIPMENT: LOGGED
Truck MAA7
BY:
DRILLING METHOD: 2.25H.5.A.
SZ WL (Stabilized)
GEOTECHNICAL BOREHOLE LOG

CLIENT:
Bradley & Ball Architects, PA
PROJECT NO.:
09:28038-B
BORING NO.:
B-06
SHEET:
1 of 1
PROJECT NAME:
DRILLER/CONTRACTOR:
Davidson Charter Academy - Geo
M & M Drilling
SITE LOCATION:
Biesecker Road, Lexington, North Carolina 27292
LOSS oFCIRCULATION
iaaz
NORTHING:
EASTING:
STATION:
SURFACE ELEVATION:
eorroM of CASING764989.1
'
1623240.8
785
C
--
Plastic Limit Water Content Liquid Limit
Co
w
z
z
x o
B-
}
w
J
Z
\
®STANDARD PENETRATION BLOWS/ET
=
F
z
a
w
DESCRIPTION OF MATERIAL
ROCK QUALITY DESIGNATION&RECOVERY
w
J
a
<
J
a
V
Q
j
ROD
Q
Q
w
Co
- REC
O CALIBRATED PENETROMETER TON/SF
[FINES CONTENT] %
Topsoil Thickness[1.00"]
4-5-6
(MH) Residuum, ELASTIC SILT, contains
S-1
SS
18
15
mica, red and brown, moist, stiff
(11)
3-5-8
(13)
,3
S-2
SS
18
18
5
780
(ML) SANDY SILT, contains mica, brown
S-3
SS
18
18
and red moist stiff
4-5-6
END OF BORING AT 7.6 FT
10
775
15
770
20
765
25
760
30
755
THE STRATIFICATION LINES REPRESENT THE APPROXIMATE BOUNDARY LINES BETWEEN SOIL TYPES. IN -SITU THE TRANSITION MAY BE GRADUAL
SZ WL (First Encountered) Dry
BORING STARTED: May 042022
CAVE IN DEPTH: 3.40
1 WL (Completion) Dry
BORING May 042022
COMPLETED:
HAMMER TYPE:
7 WL (Seasonal High Water)
EQUIPMENT: LOGGED
Truck MAA7
BY:
DRILLING METHOD: 2.25H.5.A.
SZ WL (Stabilized)
GEOTECHNICAL BOREHOLE LOG

CLIENT:
Bradley & Ball Architects, PA
PROJECT NO.:
09:28038-B
BORING NO.:
B-07
SHEET:
1 of 1
PROJECT NAME:
DRILLER/CONTRACTOR:
Davidson Charter Academy - Geo
M & M Drilling
SITE LOCATION:
Biesecker Road, Lexington, North Carolina 27292
LOSS oFCIRCULATION
iaaz
NORTHING:
EASTING:
STATION:
SURFACE ELEVATION:
eorroM of CASING765008.2
'
1622861.0
767
C
--
Plastic Limit Water Content Liquid Limit
Co
w
z
z
x o
B-
}
w
J
Z
\
®STANDARD PENETRATION BLOWS/ET
=
F
z
a
w
DESCRIPTION OF MATERIAL
ROCK QUALITY DESIGNATION&RECOVERY
w
J
a
<
J
a
V
Q
j
ROD
Q
Q
w
Co
— REC
O CALIBRATED PENETROMETER TON/SF
[FINES CONTENT] %
Topsoil Thickness[1.00"]
4-5-8
(MH) Residuum, ELASTIC SILT, contains
S-1
SS
18
18
mica, brown and red, moist, stiff
(13)
1a
4-6-9
(15)
i:s
S-2
SS
18
18
5
762
(ML) SANDY SILT, contains mica, brown
S 3
SS
18
18
and red moist stiff
4-6-7
(13)
3
END OF BORING AT 7.6 FT
10
757
15
752
20
747
25
742
30
737
THE STRATIFICATION LINES REPRESENT THE APPROXIMATE BOUNDARY LINES BETWEEN SOIL TYPES. IN -SITU THE TRANSITION MAY BE GRADUAL
SZ WL (First Encountered) Dry
BORING STARTED: May 042022
CAVE IN DEPTH: 3.25
1 WL (Completion) Dry
BORING May 042022
COMPLETED:
HAMMER TYPE:
7 WL (Seasonal High Water)
EQUIPMENT: LOGGED
Truck �MAA7
BY:
DRILLING METHOD:2.25H.5.A.
SZ WL (Stabilized)
GEOTECHNICAL BOREHOLE LOG

CLIENT:
Bradley & Ball Architects, PA
PROJECT NO.:
09:28038-B
BORING NO.:
B-08
SHEET:
1 of 1
PROJECT NAME:
DRILLER/CONTRACTOR:
Davidson Charter Academy - Geo
M & M Drilling
SITE LOCATION:
Biesecker Road, Lexington, North Carolina 27292
LOSS oFCIRCULATION
iaaz
NORTHING:
EASTING:
STATION:
SURFACE ELEVATION:
eorroM of CASING765289.1
'
1623174.7
772
C
--
Plastic Limit Water Content Liquid Limit
Co
w
z
z
x o
B-
}
w
J
Z
\
®STANDARD PENETRATION BLOWS/ET
=
F
z
a
w
DESCRIPTION OF MATERIAL
ROCK QUALITY DESIGNATION&RECOVERY
w
J
a
<
J
a
V
Q
j
ROD
Q
Q
w
Co
- REC
O CALIBRATED PENETROMETER TON/SF
[FINES CONTENT] %
Topsoil Thickness[1.00"]
4-4-5
(ML) Residuum, SANDY SILT, contains
S-1
SS
18
13
mica, dark brown and red, moist to wet,
(9)
9
stiff to firm
2-2-3
(5)
e
S-2
SS
18
8
5
767
2-3-5
($)
s
S-3
SS
18
18
END OF BORING AT 7.6 FT
10
762
15
757
20
752
25
747
30
742
THE STRATIFICATION LINES REPRESENT THE APPROXIMATE BOUNDARY LINES BETWEEN SOIL TYPES. IN -SITU THE TRANSITION MAY BE GRADUAL
SZ WL (First Encountered) Dry
BORING STARTED: May 042022
CAVE IN DEPTH: 3.30
1 WL (Completion) Dry
BORING May 042022
COMPLETED:
HAMMER TYPE:
7 WL (Seasonal High Water)
EQUIPMENT: LOGGED
Truck MAA7
BY:
DRILLING METHOD: 2.25H.5.A.
SZ WL (Stabilized)
GEOTECHNICAL BOREHOLE LOG

CLIENT:
Bradley & Ball Architects, PA
PROJECT NO.:
09:28038-B
BORING NO.:
B-09
SHEET:
1 of 1
PROJECT NAME:
DRILLER/CONTRACTOR:
Davidson Charter Academy - Geo
M & M Drilling
SITE LOCATION:
Biesecker Road, Lexington, North Carolina 27292
LOSS oFCIRCULATION
iaaz
NORTHING:
EASTING:
STATION:
SURFACE ELEVATION:
eorroM of CASING765066.0
'
1623666.3
793
C
--
Plastic Limit Water Content Liquid Limit
Co
w
z
z
x o
B-
}
w
J
Z
\
®STANDARD PENETRATION BLOWS/ET
=
F
z
a
w
DESCRIPTION OF MATERIAL
ROCK QUALITY DESIGNATION&RECOVERY
w
J
a
<
J
a
V
Q
j
ROD
Q
v7
Q
Zi
w
Co
_ REC
O CALIBRATED PENETROMETER TON/SF
[FINES CONTENT] %
Topsoil Thickness[1.00"]
4-4-4
(ML) Residuum, SANDY SILT, contains
S-1
SS
18
14
mica, brown and red, moist, firm to very
(8)
8
stiff
3-7-13
(20)
o
S-2
SS
18
18
5
788
6-9-13
(22)
2
S-3
SS
18
18
END OF BORING AT 7.6 FT
10
783
15
778
20
773
25
768
30
763
THE STRATIFICATION LINES REPRESENT THE APPROXIMATE BOUNDARY LINES BETWEEN SOIL TYPES. IN -SITU THE TRANSITION MAY BE GRADUAL
SZ WL (First Encountered) Dry
BORING STARTED: May 042022
CAVE IN DEPTH: 3.25
1 WL (Completion) Dry
BORING May 042022
COMPLETED:
HAMMER TYPE:
7 WL (Seasonal High Water)
EQUIPMENT: LOGGED
Truck MAA7
BY:
DRILLING METHOD: 2.25H.5.A.
SZ WL (Stabilized)
GEOTECHNICAL BOREHOLE LOG

CLIENT:
Bradley & Ball Architects, PA
PROJECT NO.:
09:28038-B
BORING NO.:
B-10
SHEET:
1 of 1
PROJECT NAME:
DRILLER/CONTRACTOR:
Davidson Charter Academy - Geo
M & M Drilling
SITE LOCATION:
Biesecker Road, Lexington, North Carolina 27292
LOSS oFCIRCULATION
iaaz
NORTHING:
EASTING:
STATION:
SURFACE ELEVATION:
eorroM of CASING765388.8
'
1623427.2
784
C
--
Plastic Limit Water Content Liquid Limit
Co
w
z
z
x o
B-
}
w
J
Z
\
®STANDARD PENETRATION BLOWS/ET
=
F
z
a
w
DESCRIPTION OF MATERIAL
ROCK QUALITY DESIGNATION&RECOVERY
w
J
a
<
J
a
V
Q
j
ROD
Q
v7
Q
Zi
w
Co
_ REC
O CALIBRATED PENETROMETER TON/SF
[FINES CONTENT] %
Topsoil Thickness[1.00"]
4-4-4
(MH) Residuum, ELASTIC SILT, contains
S-1
SS
18
12
mica, brown and red, moist, firm to stiff
(8)
8
3-5-8
(13)
�3
S-2
SS
18
18
5
779
(ML) SANDY SILT, contains mica, brown,
S 3
SS
18
18
red and yellow, moist, stiff
3-4-5
(9)
9
END OF BORING AT 7.6 FT
10
774
15
769
20
764
25
759
30
754
THE STRATIFICATION LINES REPRESENT THE APPROXIMATE BOUNDARY LINES BETWEEN SOIL TYPES. IN -SITU THE TRANSITION MAY BE GRADUAL
= WL (First Encountered) Dry
BORING STARTED: May 042022
CAVE IN DEPTH: 3.20
1 WL (Completion) Dry
BORING May 042022
COMPLETED:
HAMMER TYPE:
7 WL (Seasonal High Water)
EQUIPMENT: LOGGED
Truck MAA7
BY:
DRILLING METHOD: 2.25H.5.A.
SZ WL (Stabilized)
GEOTECHNICAL BOREHOLE LOG

CLIENT:
Bradley & Ball Architects, PA
PROJECT NO.:
09:28038-B
BORING NO.:
B-11
SHEET:
1 of 1
PROJECT NAME:
DRILLER/CONTRACTOR:
Davidson Charter Academy - Geo
M & M Drilling
SITE LOCATION:
Biesecker Road, Lexington, North Carolina 27292
LOSS oFCIRCULATION
iaaz
NORTHING:
EASTING:
STATION:
SURFACE ELEVATION:
eorroM of CASING765582.3
'
1623273.8
787
C
--
Plastic Limit Water Content Liquid Limit
Co
w
z
z
x o
B-
}
w
J
Z
\
®STANDARD PENETRATION BLOWS/ET
=
F
z
a
w
DESCRIPTION OF MATERIAL
ROCK QUALITY DESIGNATION&RECOVERY
w
J
a
<
J
a
V
Q
j
ROD
Q
v7
Q
Zi
w
Co
_ REC
O CALIBRATED PENETROMETER TON/SF
[FINES CONTENT] %
Topsoil Thickness[1.00"]
3-5-6
(ML) Residuum, SANDY SILT, contains
S-1
SS
18
15
mica, red, brown and yellow, moist, firm
(11)
to stiff
3-3-5
(8)
8
S-2
SS
18
18
5
782
3-4-4
(8)
8
S-3
SS
18
18
END OF BORING AT 7.6 FT
10
777
15
772
20
767
25
762
30
757
THE STRATIFICATION LINES REPRESENT THE APPROXIMATE BOUNDARY LINES BETWEEN SOIL TYPES. IN -SITU THE TRANSITION MAY BE GRADUAL
SZ WL (First Encountered) Dry
BORING STARTED: May 042022
CAVE IN DEPTH: 3.30
1 WL (Completion) Dry
BORING May 042022
COMPLETED:
HAMMER TYPE:
7 WL (Seasonal High Water)
EQUIPMENT: LOGGED
Truck MAA7
BY:
DRILLING METHOD: 2.25H.5.A.
SZ WL (Stabilized)
GEOTECHNICAL BOREHOLE LOG

CLIENT:
Bradley & Ball Architects, PA
PROJECT NO.:
09:28038-B
BORING NO.:
B-12
SHEET:
1 of 1
PROJECT NAME:
DRILLER/CONTRACTOR:
Davidson Charter Academy - Geo
M & M Drilling
SITE LOCATION:
Biesecker Road, Lexington, North Carolina 27292
LOSS oFCIRCULATION
iaaz
NORTHING:
EASTING:
STATION:
SURFACE ELEVATION:
eorroM of CASING765572.0
'
1623583.7
788
C
--
Plastic Limit Water Content Liquid Limit
Co
w
z
z
x o
B-
}
w
J
Z
\
®STANDARD PENETRATION BLOWS/ET
=
F
z
a
w
DESCRIPTION OF MATERIAL
ROCK QUALITY DESIGNATION&RECOVERY
w
J
a
<
J
a
V
Q
j
ROD
Q
v7
Q
Zi
w
Co
_ REC
O CALIBRATED PENETROMETER TON/SF
[FINES CONTENT] %
Topsoil Thickness[1.00"]
3-5-5
(ML) Residuum, SANDY SILT, contains
S-1
SS
18
16
mica, brown and red, moist, stiff
(10)
,o 3P3 [7s.or]
4-6-8
(14)
is
S-2
SS
18
18
5
783
4-5-6
(11)
S-3
SS
18
18
END OF BORING AT 7.6 FT
10
778
15
773
20
768
25
763
30
758
THE STRATIFICATION LINES REPRESENT THE APPROXIMATE BOUNDARY LINES BETWEEN SOIL TYPES. IN -SITU THE TRANSITION MAY BE GRADUAL
SZ WL (First Encountered) Dry
BORING STARTED: May 042022
CAVE IN DEPTH: 3.00
1 WL (Completion) Dry
BORING May 042022
COMPLETED:
HAMMER TYPE:
7 WL (Seasonal High Water)
EQUIPMENT: LOGGED
Truck MAA7
BY:
DRILLING METHOD: 2.25H.5.A.
SZ WL (Stabilized)
GEOTECHNICAL BOREHOLE LOG

M
O
787
------------------
787
Topsoil
785
-------------------------------------------------------------------------------------------------------------------------------------------------------------
----------
----------------------------------------------
785
N
12
O
783
---------------------------------------------------------------------------------------------------------------------------m----------------
*
--------------------------
----------------------------------------------
783
Topsoil
22
781
------------------------------------------------------------------------------------------------------------------------
---------------------------------------
----------------------------------------------
781
12
779
------------------------------------------------------------------------------------------------------------------------
----------------------------23---------
----------------------------------------------
779
23
ML
777
------------------------------------------------------------------------------------------------------------------------
----------------------------24
--------
----------------------------------------------
777
O
Topsoil
ML
773
----------------------------------------
-------------------------------------------------------------
27--------
---------------------------------------
----------------------------------------------
773
11
14
771
-------------------------------------------------
---------------------------------------------------------------
---------------------------------------
----------------------------------------------
771
17
769
-------------------------------------------------
---------------------------------------------------------------
---------------------------------------
----------------------------------------------
769
21
767
--------------------------------------
26-----------------------------------------------------------------------
-----------------------------
-
767
ML
765
---------------------------------------34--------
---------------------------------------------------------------
---------------------------------------
----------------------------------------------
765
9
761
-------------------------------------------------
---------------------------------------------------------------
---------------------------------------
Eoe @zs----------------------------------------------
761
23
Legend
759
. .
SM
759
Key757
14
-------------------------------------------------
------------------------------------------
-------- Eoe @zs
---------------------------------------------------------------------------------------------
757
Topsoil
SILT
SILTY--------------------------------------------------------------------------------------------------------------------------------------------------------
SAND
751
6M
751
748.00
749
-------------------------------------------------
Eoe@zs--------------------------------------------------------------------------------------------------------------------------------------------------------------------
749
OO
Cl)N
CD
O�
�O
(hN
N
cM
c`")
Notes:
Plastic Limit Water Content Liquid Limit
Q
WL (First Encountered)
Fill
Rw
X °
GENERALIZED
SUBSURFACE SOIL PROFILE Section A -A'
[FIN ES CONTENT%]
WL(COmpletl0n)
Possible FIII
TEOB. END OF BORING AR. AUGER REFUSAL SR'. SAMPLER REFUSAL.
2-THE NUMBER BELOW THE STRIPS IS THE DISTANCE ALONG THE BASELINE.
Davidson Charter Academy - Geo
& SEE INDIVIDUAL BORING LOG AND GEOTECHNICAL INFORMATION.
EE
` BOTTOM OF CASING
7
WL (Seasonal High Water)
Probable Fill
4-STANDARD PENETRATION TEST RESISTANCE
D,sas)
(LEFT OF BORING) IN BLOWS PER FOOT (ASTM
Bradley & Ball Architects, PA
taa> LOSS OF
Q
Q
WL (Stabilized)
Rock
Biesecker Road, Lexington, North Carolina 27292
Pro iect No:
os:zaoaa-e I Date: osnarzozz
CIRCULATION
6-

APPENDIX C — Laboratory Testing
Laboratory Test Results Summary
Liquid and Plastic Limits Test Results

786
------------------------------------------------------------------------------------------------------------------------------------------------------------------M------------
Lo
R
Topsoil
784
---------------------------------------------------------------------------------------------------------------------------------------------------------------
---------
5
782
------------------------------------------------------------a-------------------------------------------------------------------------------------------------
O
---------
m 30
---------------------------------------------------------------------------------------
Topsoil
778
---------------------------------------------- -1.2-------- ----------------------------------------------------------------------------------- 23--------
ML
---------
776
23 -----------------------------------------------------------------------------------1S -
---------
774
-------------------------------------------------------------------------------------------------------------------------------------------------------
---------
29
772
--------------------------------------------------------- ----ML--------------------------------------------------------------------------------------
---------
25 3
ML
770
-------------------------------------------------------------------------------------------------------------------------------------------------------
---------
768
-------------------------------------------------------------------------------------------------------------------------------------------------------
-
---------
766
'r8------------------------------------------------ --------------------------------------------4---------:::
---------
764
-------------------------------------------------------------------------------------------------------------------------------------------------------
- - -
---------
762
-------------------------------------------------------------------------------------------------------------------------------------------------------
- :
---------
11 ML 4
760
-------------------------------------------------------------------------------------------------------------------------------------------------------
: - :
---------
758
--------------------------------------------------------- -----------------------------------------------------------------------------------------------
::
SM
SM
756
Legend
-----------------------------------------------9-------- : 6
FOB
Key754
@25
---------------------------------------------------------------------------------------------------------------------------------------------------------------
---------
Topsoil 752
01
---------
SILT750
---------------------------------------------------------------------------------------------------------------------------------------------------------------
==
SILTY748
---------------------------------------------------------------------------------------------------------------------------------------------------
SAND
744.00 746
11
786
784
782
780
778
776
774
772
770
768
766
764
762
760
758
756
754
752
750
748
746
O
CD
6N
M
V pp
O (�
O
N( V
Notes:
1-EOB. END OF BORING AR. AUGER REFUSAL SR'. SAMPLER REFUSAL.
2-THE NUMBER BELOW THE STRIPS IS THE DISTANCE ALONG THE BASELINE.
& SEE INDIVIDUAL BORING LOG AND GEOTECHNICAL INFORMATION.
4-STANDARD PENETRATION TEST RESISTANCE (LEFT OF BORING) IN BLOWS PER FOOT (ASTM
D1586).
Plastic Limit Water Content Liquid Limit
X 40A
Q
WL (First Encountered)
-
Fill
GENERALIZED SUBSURFACE SOIL PROFILE Section B-B'
[FIN ES CONTENT%]
WL(COmpletl0n)
Possible FIII
EE
Davidson Charter Academy - Geo
` BOTTOM OF CASING
WL (Seasonal High Water)
Probable Fill
Bradley & Ball Architects, PA
taa> LOSS OF
Q CIRCULATION
Q
WL (Stabilized)
IMIRock
Biesecker Road, Lexington, North Carolina 27292
6-
Project No: 09:28038-B Date: 05/18/2022

Laboratory Testing Summary
Atterberg Limits
"Percent
Moisture - Density
CB R (%)
Sample Location
Sample
Number
Depth
(feet)
AMC
( /o)
Soil
Type
Passing
No. 200
Sieve
#Organic
Content (%)
LL
PL
PI
<Maximum
Density (pcf)
<Optimum
Moisture (%)
0.1 in.
0.2 in.
B-02
S-1
1-2.5
24.0
'ML
48
33
15
65.9
B-05
S-1
1-2.5
22.0
'ML
45
30
15
69.0
B-12
S-1
1-2.5
31.3
NP
NP
NP
73.0
Notes: See test reports for test method, ^ASTM D2216-19,'ASTM D2488, "ASTM D1140-17, #ASTM D2974-20e1 < See test report for D4718 corrected
values
Definitions: MC: Moisture Content, Soil Type: USCS (Unified Soil Classification System), LL: Liquid Limit, PL: Plastic Limit, PI: Plasticity Index, CBR: California
Bearing Ratio, OC: Organic Content
Project: Davidson Charter Academy - Geo Project No.: 09:28038-B
Client: Bradley & Ball Architects, PA Date Reported:
Office / Lab Address Office Number / Fax
4811 Koger Boulevard [phone]
ECS Southeast LLP -Greensboro Greensboro, NC 27407
[phone]
Tested by
Checked by
Approved by
Date Received
ehuerto
MAbdelgadir
MAbdelgadir
5/17/2022

LIQUID AND PLASTIC LIMITS TEST REPORT
or
Project: Davidson Charter Academy - Geo
Project No.: 09:28038-B
Client: Bradley & Ball Architects, PA
Date Reported:
Office Lab Address
4811 Kober Boulevard
ECS Southeast LLP - Greensboro Greensboro, NC 27407
Greensboro,
Office Number/ Fax
[phone]
[phone]
60
Dashed line indicates the approximate
upper limit boundary for natural soils
50
/
P
L
Q�
A
O�
S
40
T
I
C
I
T
Y
30
I
N
D
E
X
"'
� t
10
CL-ML
ML or OL
MH or OH
0 �
0 10
20 30 40 50
60
70 80
90
LIQUID
LIMIT
TEST RESULTS (ASTM D4318-10 (MULTIPOINT TEST))
Sample
Location
Sample
Number
Sample
Depth (ft)
Tested by
Checked by
Approved by
Date Received
ehuerto
MAbdelgadir
MAbdelgadir
5/17/2022