Sandy Lk Cross L3R-LR180914
Geotechnical Engineering Report
Proposed Capital One Bank
Coppell, Texas
April 26, 2018
Terracon Project No. 95145008
Prepared for:
Levinson Alcoser Associates, L.P.
Houston, Texas
Prepared by:
Terracon Consultants, Inc.
Fort Worth, Texas
TABLE OF CONTENTS
Page
EXECUTIVE SUMMARY ............................................................................................................. i
1.0 INTRODUCTION ............................................................................................................. 1
2.0 PROJECT INFORMATION ............................................................................................. 1
2.1 Project Description ............................................................................................... 1
2.2 Site Location and Description............................................................................... 2
3.0 SUBSURFACE CONDITIONS ........................................................................................ 2
3.1 Typical Profile ...................................................................................................... 2
3.2 Groundwater ........................................................................................................ 3
4.0 RECOMMENDATIONS FOR DESIGN AND CONSTRUCTION ...................................... 3
4.1 Geotechnical Considerations ............................................................................... 3
4.2 Earthwork............................................................................................................. 4
4.2.1 Existing Fills ............................................................................................. 4
4.2.2 Site Preparation ........................................................................................ 4
4.2.3 Suitable Fill ............................................................................................... 5
4.2.4 Compaction Requirements ....................................................................... 5
4.2.5 Drainage and Utilities ............................................................................... 6
4.3 Shallow Foundations ............................................................................................ 6
4.3.1 Shallow Footing ........................................................................................ 6
4.3.2 Monolithic Slab-on-Grade: Slab Design Recommendations ...................... 7
4.3.3 Shallow Foundations - Construction Considerations ................................. 8
4.4 Deep Foundations................................................................................................ 9
4.4.1 Underreamed Shafts ................................................................................ 9
4.4.2 Drilled and Underreamed Shafts - Construction Considerations ............. 10
4.4.3 Lateral Capacity...................................................................................... 10
4.4.4 Uplift ....................................................................................................... 10
4.4.5 Drilled Shaft Construction Considerations............................................... 11
4.4.6 Grade Beams/Pier Caps/Wall Panels ..................................................... 11
4.5 Seismic Considerations...................................................................................... 12
4.6 Floor Systems .................................................................................................... 12
4.7 Pavements ......................................................................................................... 13
4.7.1 Pavement Subgrades ............................................................................. 13
4.7.2 Pavement Traffic .................................................................................... 14
4.7.3 Pavement Sections ................................................................................. 14
5.0 GENERAL COMMENTS ............................................................................................... 15
APPENDIX A – FIELD EXPLORATION
Exhibit A-1 Boring Location Plan
Exhibit A-2 Field Exploration Description
Exhibits A-3 through A-11 Boring Logs
APPENDIX B – LABORATORY TESTING
Exhibit B-1 Laboratory Testing
Exhibit B-2 Grain Size Distribution
APPENDIX C – SUPPORTING DOCUMENTS
Exhibit C-1 General Notes
Exhibit C-2 Unified Soil Classification System
Geotechnical Engineering Report
Proposed Capital One Bank ■ Coppell, Texas
April 26, 2018 ■ Terracon Project No. 95145008
Responsive ■ Resourceful ■ Reliable i
EXECUTIVE SUMMARY
A geotechnical investigation has been performed for the proposed building in Coppell, Texas. Ten
borings were drilled for the geotechnical studies performed in 2014 and 2018. The borings were
advanced to depths ranging from 5 to 25 feet. The following geotechnical considerations were
identified:
On-site native soils appear suitable for use as general site fill.
If movements on the order of one inch can be tolerated, the building wall and column loads
can be supported on shallow footings bearing in properly compacted on-site soils.
Underreamed drilled shaft are recommended if foundation movements are to be limited to
less than 1 inch.
The site soils are considered relatively stable with respect to moisture -induced volume
changes (expansion or contraction). If movements on the order of 1 inch are acceptable
for grade supported slabs, the floor slabs can be placed on a properly compacted subgrade.
If floor slab movements are to be limited to about ¾ inch or less, a structural floor system
supported on underreamed drilled shafts is recommended.
The 2015 International Building Code, Table 1613.5.2 IBC seismic site classification for
this site is D.
Asphaltic concrete pavement or Portland cement concrete pavement can be used at this site.
If asphaltic concrete is used, the subgrade should be modified with lime. Portland cement
concrete pavements can be placed on a compacted subgrade without lime. These
pavements are not equal in performance. The Portland cement concrete pavement is
expected to require less maintenance.
This summary should be used in conjunction with the entire report for design purposes. It should
be recognized that details were not included or fully developed in this section, and the report must
be read in its entirety for a comprehensive understanding of the items contained herein. The section
titled GENERAL COMMENTS should be read for an understanding of the report limitations.
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GEOTECHNICAL ENGINEERING REPORT
PROPOSED CAPITAL ONE BANK
COPPELL, TEXAS
Terracon Project No. 95145008
April 26, 2018
1.0 INTRODUCTION
A new bank building is planned for construction in Coppell, Texas. Our scope of services for the
project included drilling and sampling ten borings to depths of about 5 to 25 feet, laboratory testing,
and engineering analysis. Six borings were drilled for the geotechnical study performed in 2014.
Four additional borings were drilled in 2018 to evaluate current soil conditions had changed. The
purpose of these services is to provide information and geotechnical engineering recommendations
relative to:
▪ subsurface soil conditions
▪ groundwater conditions
▪ earthwork
▪ foundation design and construction
▪ seismic considerations
▪ floor slabs and building pad preparation
▪ pavement sections and subgrade
preparation
2.0 PROJECT INFORMATION
2.1 Project Description
ITEM DESCRIPTION
Planned improvements An approximately 3,555 square feet single-story Bank building with
associated drive-thru and parking areas
Finished floor elevations Unknown, assumed to be ±2 feet of existing grades
Maximum loads (assumed)
Columns: 75 kips
Walls: 4 kips per linear foot
Slabs: 150 psf
Retaining/below grade walls None anticipated
Pavements Traffic will include automobile, light trucks, fire trucks, and garbage
trucks. The pavement design period is assumed 20 years.
Geotechnical Engineering Report
Proposed Capital One Bank ■ Coppell, Texas
April 26, 2018 ■ Terracon Project No. 95145008
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2.2 Site Location and Description
ITEM DESCRIPTION
Location Southwest corner of Sandy Lake Road and S. Denton Tap Road in
Coppell, Texas
Existing improvements None
Structures Occupied in the
Past A gas station with underground storage tanks and piping was removed
Current ground cover Grass and some trees
Existing topography Relatively flat
3.0 SUBSURFACE CONDITIONS
3.1 Typical Profile
Based on the results of the borings, subsurface conditions on the project site can be generalized as
follows:
Stratum Approximate Depth to
Bottom of Stratum Material Encountered Consistency /
Density
11 2 to 13 feet Fill – dark brown, brown, and tan sandy
lean clay (CL) and clayey sand (SC) Loose to hard
22 4 to 15 feet Dark gray-brown clayey sand (SC) Medium dense
to dense
33 5 to 25 feet Gray-brown, brown, tan and gray sandy
lean clay (CL) Stiff to hard
44 15 feet Gray-tan poorly graded sand (SP) medium dense
Note 1 - present in borings B-3, B-5 and B-101 through B-104
Note 2 - present in boring B-3, and B-103
Note 3 - present at the termination of all borings with the exception of B-5
Note 4 - present at the termination of boring B-5
Conditions encountered at the boring locations are indicated on the boring logs. Stratification
boundaries on the boring logs represent the approximate location of changes in soil types; in -situ,
the transition between materials may be gradual. Details can be found on the boring logs in
Appendix A of this report.
Geotechnical Engineering Report
Proposed Capital One Bank ■ Coppell, Texas
April 26, 2018 ■ Terracon Project No. 95145008
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3.2 Groundwater
The borings were advanced using dry auger drilling techniques that allow short-term groundwater
observations to be made while drilling. Groundwater observations obtained during and at the
completion of drilling are noted in the table below.
Boring No. Boring Termination
Depth (feet)
Approximate Depth to Groundwater (feet)
While advancing the
boring (feet)
At the completion of
drilling (feet)
B-1 25 22 Not present
B-3 25 22 22
B-104 15 6 Not present
Remaining borings - Not encountered Not present
These groundwater level observations provide an indication of groundwater conditions present at
the time the borings were drilled. Groundwater level fluctuations occur due to seasonal variations
in the amount of rainfall, runoff and other factors not evid ent at the time the borings were
performed. Therefore, groundwater levels during construction or at other times in the life of the
structure may be higher or lower than the levels indicated on the boring logs. The possibility of
groundwater level fluctuations should be considered when developing the design and construction
plans for the project.
4.0 RECOMMENDATIONS FOR DESIGN AND CONSTRUCTION
4.1 Geotechnical Considerations
Fill material was encountered in some of the borings to a depth of up to 13 feet. The fill material
consisted of sandy lean clays and clayey sands. There is a possibility of deeper fills at this site
and under-compacted zones of soil or debris within the fill materials. Under -compacted fill could
lead to unacceptable settlements of foundations, floor slabs, and pavements. This risk of
unforeseen conditions cannot be eliminated without completely removing the existing fill.
The natural site soils are considered relatively stable with respect to moisture -induced volume
changes (expansion or contraction). We estimate a potential vertical rise (PVR) of about 1 inch
for the soils at this site. Based on the conditions encountered in the borings, the proposed
structure can be supported on shallow footing foundations bearing in properly compacted on-site
soils provided 1 inch of potential movement is acceptable and existing fill layers within the building
foot print are removed and reinstalled in a controlled manner .
Geotechnical Engineering Report
Proposed Capital One Bank ■ Coppell, Texas
April 26, 2018 ■ Terracon Project No. 95145008
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A deep foundation system in conjunction with a structurally suspended floor slab is recommended
if foundation and floor slab movements are to be limited to less than 1 inch. Note that potential
movements of about 1 inch will exist for grade supported slabs such as parking lots and
pavements.
Portland cement concrete pavement can be used at this site. Portland cement concrete pavements
can be placed on a properly compacted subgrade.
Geotechnical recommendations for building foundations, floor slabs, earthwork and pavements are
presented in the following report sections.
4.2 Earthwork
4.2.1 Existing Fills
Existing fill materials consisting of sandy lean clays and clayey sands were encountered to depths
about 2 to 13 feet in borings B-3, B-5 and B-101 thought B-104. The deeper fills appear to be
associated with backfilling of the previously buried petroleum storage tanks. The possibility of
deeper fills at this site and under compacted zones of soil or debris within the fill materials exists.
If the entire thickness of fill material is not reworked, then the possibility of undesirable settlements
of foundations, floor slabs and pavements exist. Reworking of all the fill is the only method of
eliminating the risk of unusual settlement.
Note that the previous tank bed is located outside the planned new building location. In areas
outside of the building pad, proof-rolling, as described below in section 4.2.2 Site Preparation,
can be considered in lieu of complete removal of the fill . Proof-rolling is intended to represent a
reasonable approach for construction; however, it will not eliminate the risk of unexpected
movements in some areas.
It is our understanding that the tank hold is outside the building area. As a minimum, the fill
materials in underground storage tank areas should be excavated to a depth of 5 feet and
replaced with proper moisture/density control. The excavated soils can be reused. If soft/ loose
soils are present at the bottom of the excavat ion, the excavation should be extended to firm
ground. The horizontal extents of the excavation should be determined during the excavation
based on the materials observed on the sides of the excavation.
4.2.2 Site Preparation
Existing utility lines should be removed or fully grouted to prevent moisture intrusion into the site
soils. Existing vegetation, deleterious materials, concrete, and other organics should be removed.
Prior to placing any fill, the exposed subgrade should be proof -rolled. Existing fill material should
be removed from the building area and 5 feet beyond building edge . The proof-rolling should be
performed with a fully loaded, tandem-axle dump truck or other equipment providing an equivalent
subgrade loading.
Geotechnical Engineering Report
Proposed Capital One Bank ■ Coppell, Texas
April 26, 2018 ■ Terracon Project No. 95145008
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A minimum gross weight of 20 tons is recommended for the proof -rolling equipment. The proof-
rolling should consist of several overlapping passes in mutually perpendicular directions over a
given area. Any soft or pumping areas should be excavated to firm ground. Excavated area s
should be backfilled with properly placed and compacted fill as discussed section 4.2.4
Compaction Requirements.
4.2.3 Suitable Fill
The following soil materials are discussed in the coming sections of this report. The following
table summarizes their nomenclature, detailed descriptions, and appropriate usage in the context
of this project.
Nomenclature Technical Requirements Appropriate Use
On-site soils
Free of vegetation, decomposable material,
debris, and rocks greater than 4 inches in
maximum dimension
1) General site grading
2) Building pad (below upper 1 foot
of select fill or flexible base)
3) Pavement subgrades
4) Utility trench backfill
Imported fill
Clean clay soil (free of decomposable/
deleterious material and debris) with a liquid
limit (LL) less than 40 and a plasticity index (PI)
between 6 and 25 percent and no rock greater
than 4 inches in maximum dimension
Select fill
Sandy clay to clayey sand with a liquid limit (LL)
of less than 35 percent and a plasticity index
(PI) between 6 and 15
1) Upper 1 foot of the building pad
(below grade-supported floor
slab)
2) Below pavements Flexible base
TxDOT* Item 247, Type D, Grade 1 or 2.
Recycled concrete meeting this gradation is
acceptable.
* TxDOT – Texas Department of Transportation
4.2.4 Compaction Requirements
Recommendations for compaction are presented in the following table. We recommend
engineered fill be tested for moisture content and compaction during placement. Should the
results of the in-place density tests indicate the specified moisture or compaction limits have not
been met, the area represented by the test should be reworked and retested as required until the
specified moisture and compaction requirements are achieved.
ITEM DESCRIPTION
Subgrade preparation to receive fill Surface scarified to a minimum depth of 6 inches and
compacted to criteria below
Loose lift thickness 9-inches or less
Geotechnical Engineering Report
Proposed Capital One Bank ■ Coppell, Texas
April 26, 2018 ■ Terracon Project No. 95145008
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ITEM DESCRIPTION
Subgrade and fill compaction
requirements1
A minimum of 95% maximum standard Proctor dry density
(ASTM D 698) at or above optimum moisture content
1. The compaction criteria in fire lanes and roadways must meet the requirements, if any, as prescribed
by the local governing authority.
4.2.5 Drainage and Utilities
The flatwork abutting the structure should be sloped down to provide effective drainage away
from the building. Where paving or flatwork abuts the structure, the joints should be properly
sealed and maintained to prevent the infiltration of surface water. Open ground should be sl oped
on 5 percent or steeper grades for 10 or more feet away from the building. Roof drains should
discharge on paved surface or be extended away from the structure. The on -site soils are
susceptible to erosion and will require protection .
Care should be taken that utility trenches are properly backfilled. Backfilling should be
accomplished with properly compacted on-site soils.
4.3 Shallow Foundations
4.3.1 Shallow Footing
The footings should be founded on properly compacted soils as described in section 4.2.2 Site
Preparation. Design recommendations are presented below.
Description Wall and Column Footings
Net allowable bearing pressure for
footings bearing on natural soils or
compacted fill1
1,800 psf
Minimum dimension 18 inches 36 inches
Minimum embedment below lowest
adjacent grade 36 inches
Approximate total movement 2 1 inch 1 inch
Estimated differential movement 2 <1 inch over 40 feet ½ inch between columns
Allowable passive pressure 3 150 psf/ft triangular distribution
Coefficient of sliding friction 3 0.35
Geotechnical Engineering Report
Proposed Capital One Bank ■ Coppell, Texas
April 26, 2018 ■ Terracon Project No. 95145008
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Description Wall and Column Footings
1. The recommended net allowable bearing pressure is the pressure in excess of the minimum
surrounding overburden pressure at the footing base elevation, and assumes any unsuitable fill or
soft soils, if encountered, will be undercut and replaced with engineered fill.
2. The foundation movement will depend upon the variations within the subsurface soil profile, the
structural loading conditions, the embedment depth of the footings, the thickness of compacted fill,
and the quality of the earthwork operations.
3. The sides of the excavation for the spread footing foundation must be nearly vertical and the concrete
should be placed neat against these vertical faces for the passive earth pressure values to be valid.
If the loaded side is sloped or benched, and then backfilled, the allowable passive pressure will be
significantly reduced. Passive resistance in the upper 3 feet of the soil profile should be neglected.
4.3.2 Monolithic Slab-on-Grade: Slab Design Recommendations
Conventionally reinforced slab -on-grade foundation systems may be considered to support the
proposed structure. Monolithic slab foundations are typically designed with interior and exterior
grade beams to resist soil movement. The slab, superstructure, architectural finishes, and
entrances must be designed to accommodate potential d ifferential movements from active soils.
Potential movements of slab -on-grade foundation placed on existing soils are estimated to be
about 1 inch.
Recommendations provided below are based on “Design of Slab-on-grade Foundations” (August
1981) and “Design of Slab-on-grade Foundations – An Update” (March 1996) prepared for Wire
Reinforcement Institute (WRI). The design parameters were developed based on WRI procedure
and recommended ground modification.
Design Parameter
Recommendations
In-situ Subgrade
Design Plasticity Index (PI) 18
Climatic rating (Cw) 18
Cantilever distance (lC) 1.5 feet
Allowable net bearing capacity 2,000 psf
Minimum bearing depth (inches) 24
Consideration can also be given to supporting the structure on a post -tensioned slab-on-grade
foundation. The slab, superstructure, architectural finishes, and entrances must be designed to
accommodate potential differential movements from active soils.
Geotechnical Engineering Report
Proposed Capital One Bank ■ Coppell, Texas
April 26, 2018 ■ Terracon Project No. 95145008
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4.3.3 Shallow Foundations - Construction Considerations
Footing excavations should be protected from standing water or desiccation. The base of all
foundation excavations should be free of water and loose soil and rock prior to placing concrete.
Due to the sandy nature of the soils, we recommend the base of the footing excavations be
compacted prior to placement of steel and concrete. Excavation of individual footings or sections
of continuous footings, placement of steel and concrete, and backfilling should be completed in a
reasonably continuous manner. It is preferable that complete installation of individual footings or
sections of continuous footings be accomplished in 48 hours.
If the supporting soils in the bottom of the footing become disturbed or unsuitable bearing soils
are encountered in footing excavations, the excavations should be extended deeper to suitable
soils where the footings could bear directly on these soils at the lower level or on lean concrete
backfill placed in the excavations. The footings could also bear on properly compacted backfill or
flexible base extending down to the suitable soils. Over excavation for compacted backfill
placement below footings should extend laterally beyond all edges of the footings at leas t 8 inches
per foot of over excavation depth below footing base elevation. The over excavation should then
be backfilled up to the footing base elevation with properly compacted fill as described in section
4.2 Earthwork. The over excavation and backfill procedures are described in the figures below
(shallow footing only).
Backfilling adjacent and over footings should proceed as soon as practical to reduce disturbance.
Backfilling should be accomplished using soils similar to those excavated. All bac kfill should be
uniformly compacted to the criteria presented in section 4.2.4 Compaction Requirements of this
report.
All footing installations should be inspected by qualified geotechnical personnel to help verify the
design depth and perform related duties.
Geotechnical Engineering Report
Proposed Capital One Bank ■ Coppell, Texas
April 26, 2018 ■ Terracon Project No. 95145008
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4.4 Deep Foundations
4.4.1 Underreamed Shafts
Drilled and underreamed shafts should be designed in accordance with the recommendations
provided in the following table.
Drilled and Underreamed Shaft Design Summary 1
Design Parameter Recommendation
Bearing stratum 2 Tan and gray sandy lean clay
Bearing depth Minimum of 12 feet below finish grade
Allowable bearing pressure 3,000 psf
Uplift resistance Quplift (lbs)
Quplift = 0.449 * Nu * Su * (Bb2 – B2).
Nu = 4*(Db/Bb) – 3
Db/Bb varies between 0.75 and 2.5
For Db/Bb < 0.75 increase Db
For Db/Bb > 2.5 use Db/Bb = 2.5
Su = undrained shear strength(psf) averaged over 2Bb or Db
above the base of the bell whichever is smaller
Su = 1,500 psf
The value of Quplift obtained using this equation includes a
factor of safety of 2.0
Db, Bb, and B in feet
Minimum bell to shaft diameter ratio 2 to 1
Maximum bell to shaft diameter ratio 3 to 1
Minimum bell diameter 30 inches larger than the straight shaft portion
Minimum underream edge to
underream edge spacing
One underream diameter, based on the larger of the two.
Closer drilled shaft spacing should be evaluated by Terracon
to determine if reductions in the allowable bearing pressures
should be made to control settlement.
Total settlement Less than ¾ inch for maximum column load of 75 kips
Differential settlement ½ to ¾ of the total settlement
1. Design capacities are dependent upon the method of installation, and quality control parameters. The
values provided are estimates and should be verified when installation protocol have been finalized.
2. See Subsurface Profile in Geotechnical Characterization for more details on stratigraphy.
Geotechnical Engineering Report
Proposed Capital One Bank ■ Coppell, Texas
April 26, 2018 ■ Terracon Project No. 95145008
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4.4.2 Drilled and Underreamed Shafts - Construction Considerations
The construction of all drilled shafts should be observed by experienced geotechnical personnel
during construction to confirm: 1) the bearing stratum; 2) the minimum bearing depth; 3) that
groundwater seepage is correctly handled; and 4) that the shafts a re within acceptable vertical
tolerance.
Recommendations for drilled shaft construction are presented in the following table.
Item Recommendation
Drilled shaft installation specification Current version of American Concrete Institute’s “Standard
Specification for the Construction of Drilled Piers” ACI 336.
Top of shaft completion Enlarged (mushroom-shaped) top in contact with the clays
should not be allowed.
Time to complete Complete installation of individual underreamed shafts should be
completed within one day.
Special conditions
Shaft excavations should be installed using dry methods. The
concrete should have a slump of 6 inches plus or minus 1 inch
and be placed in a manner to avoid striking the reinforcing steel
during placement. Sand was at the depth of 13 feet in Boring B-
5. If sand is encountered above the bearing depth of 12 feet, the
bottom of the drilled shaft may be raised. Terracon should be
contacted for additional recommendations if shafts must be
elevated more than 2 feet.
4.4.3 Lateral Capacity
The drilled shafts may be subject to lateral loads. Parameters for lateral load analysis are
provided in the follow table for use in Ensoft’s L-PILE computer program.
Overburden Soil Type In situ soils
LPILE Material Type Stiff clay without free water
Effective Soil Unit Weight (psf ) 120
Undrained Cohesion, c (psi) 10
Friction Angle, ɸ (degrees) 25
Strain Factor, є50 0.005
• Neglect the upper soils in areas where the top of shaft is not protected from wetting or
drying cycles.
• Neglect none replaced fills.
4.4.4 Uplift
The drilled and underreamed shafts will be subject to uplift as a result of heave in the overlying
clay soils. The magnitude of these loads varies with the shaft diameter, soil parameters, and
Geotechnical Engineering Report
Proposed Capital One Bank ■ Coppell, Texas
April 26, 2018 ■ Terracon Project No. 95145008
Responsive ■ Resourceful ■ Reliable 11
particularly the in-situ moisture levels at the time of construction. The shafts must contain
sufficient continuous vertical reinforcing and embedment depth to resist the net tensile load. For
the conditions encountered at this site, the uplift load can be approximated by assuming a uniform
uplift of 500 psf over the shaft perimeter for a depth of 8 feet.
4.4.5 Drilled Shaft Construction Considerations
The construction of all drilled shafts should be observed by experienced geotechnical personnel
during construction to confirm: 1) the bearing stratum; 2) the minimum bearing depth; 3) that
groundwater seepage is correctly handled; and 4) that the shafts are within acceptable vertical
tolerance.
Recommendations for drilled shaft construction are presented in the following table.
Item Recommendation
Drilled shaft installation
specification
Current version of American Concrete Institute’s “Standard
Specification for the Construction of Drilled Piers” ACI 336.
Top of shaft completion Enlarged (mushroom-shaped) top in contact with the clays should
not be allowed.
Time to complete
Drilled shaft construction should be completed within 8 hours of
completing the underream in a continuous manner to reduce side
wall and base deterioration.
Drilled shaft construction
Shaft excavations should be installed using dry methods. The
concrete should have a slump of 6 inches plus or minus 1 inch and
be placed in a manner to avoid striking the reinforcing steel during
placement.
Special conditions
The site soils are sandy and susceptible to sloughing/caving in
drilled shaft excavations. Close coordination of excavation and
concrete placement will reduce the potential for sloughing/caving of
the sidewalls and collapse of the bells. If sloughing/caving occurs it
may be necessary to utilize a straight sided shaft with the diameter
equal to the planned underream diameter.
Groundwater Adjustment in the bearing depth may be necessary in the field if
groundwater is encountered.
4.4.6 Grade Beams/Pier Caps/Wall Panels
In conjunction with drilled shafts, all grade beams or wall panels should be supported by the drilled
shafts. A minimum void space of 4 inches is recommended between the bottom of grade beams,
pier cap extensions or wall panels and the subgrade. This void will serve to minimize distress
resulting from swell pressures generated by the clay soils. Structural cardboard forms are one
acceptable means of providing this void beneath cast -in-place elements. Soil retainers should be
used to prevent infilling of the void.
Geotechnical Engineering Report
Proposed Capital One Bank ■ Coppell, Texas
April 26, 2018 ■ Terracon Project No. 95145008
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The grade beams should be formed rather than cast against earth trenches. Backfill against the
exterior face of grade beams, wall panels and pier caps should be on site soils placed and
compacted as described in section 4.2.4 Compaction Requirements.
4.5 Seismic Considerations
Code Used Site Classification
2009 International Building Code (IBC) 1 D 2
1. In general accordance with the 2009/2015 International Building Code, Table 1613.5.2.
2. The 2009/2015 International Building Code (IBC) uses a site soil profile determination extending a
depth of 100 feet for seismic site classification. The current scope requested does not include a
100 foot soil profile determination. Borings extended to a maximum depth of approximately 25 feet
and this seismic site class definition considers that stiff soil extends below the maximum depth of the
subsurface exploration. Additional exploration to deeper depths would be required to confirm the
conditions below the current depth of exploration. Alternatively, a geophysical exploration could be
utilized in order to attempt to justify a higher seismic site class.
4.6 Floor Systems
The potential magnitude of the moisture induced and under -compacted fill movements is rather
indeterminate. It is influenced by the soil properties, the placement method of the existing fill
material, overburden pressures, and by soil moisture levels at th e time of construction.
Based on the conditions encountered in the borings, potential vertical soil movements of the
natural soils are estimated to be about 1 inch for grade supported slabs and flatwork. It should
be realized that even slab movements of 1 inch can result in distress to floor coverings, interior
partitions, and finishes. Special provisions should be made to accommodate movement if slab -
on-grade construction is used. Sidewalks and curbs should have sufficient separation from the
architectural finishes on the building and columns to prevent distress of these elements should
differential movements occur between them. The building pad should be prepared in accordance
with the recommendations in section 4.2 Earthwork.
A structural slab in conjunction with drilled shaft foundations is recommended if floor slab
movements are to be limited to less than ¾ inch. A minimum void space of 6 inches is
recommended. The minimum void space can be provided by the use of cardboard carton forms,
or a deeper crawl space. The bottom of the void should preferably be higher than adjacent
exterior grades. A ventilated and drained crawl space is preferred under the building for several
reasons, including the following:
▪ Ground movements will affect the project utilities, which can cause breaks in the lines and
distress to interior fixtures.
Geotechnical Engineering Report
Proposed Capital One Bank ■ Coppell, Texas
April 26, 2018 ■ Terracon Project No. 95145008
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▪ A crawl space permits utilities to be hung from the superstructure, which greatly reduces
the possibility of distress due to ground movements. It also can provide re ady access in
the event repairs are necessary.
▪ Ground movements are uneven. A crawl space can be positively drained preventing the
ponding of water and reducing the possibility of distress due to unexpected ground
movements.
A vapor retarder should be used beneath concrete slabs that will be covered with wood, tile,
carpet or other moisture sensitive or impervious coverings, or when the slab will support
equipment sensitive to moisture. When conditions warrant the use of a vapor retarder, the slab
designer and slab contractor should refer to ACI 302 for procedures and cautions regarding the
use and placement of a vapor retarder.
Trees should be planted at least one -mature tree height from the building. Root barriers should
be installed if trees are plan ted closer.
4.7 Pavements
4.7.1 Pavement Subgrades
Subgrade materials at this site will most likely consist of sandy lean clays. The clayey soils are
subject to loss in support value with the moisture increases which occur beneath pavement
sections. They react with hydrated lime to improve and maintain their support value. Lime
treatment is recommended beneath flexible (asphalt) pavement sections. Rigid (concrete)
pavements may be placed on an unmodified, properly compacted subgrade.
For budgeting purposes, a minimum of 6 percent hydrated lime (TxDOT Item 260), by dry weight,
is estimated. The lime application rate should be determined by laboratory testing once the
pavement subgrade is rough graded. The lime should be thoroughly mixed and blended with the
top 6 inches of the subgrade. Lime treatment should extend a minimum of one foot beyond the
edge of the pavement.
The modified or natural subgrade should be uniformly compacted to the criteria described in
section 4.2.4 Compaction Requirements. It should then be protected and maintained in a moist
condition until the pavement is placed. Pavement subgrades should be graded to prevent
ponding and infiltration of excessive moisture on or adjacent to the pavement subgrade surface.
Site grading is generally accomplished early in the construction phase. However as construction
proceeds, the subgrade may be disturbed due to utility excavations, construction traffic,
desiccation, or rainfall. As a result, the pavement subgrade may not be suitable for pavemen t
construction and corrective action will be required. The subgrade should be carefully evaluated
at the time of pavement construction for signs of disturbance or excessive rutting. If disturbance
Geotechnical Engineering Report
Proposed Capital One Bank ■ Coppell, Texas
April 26, 2018 ■ Terracon Project No. 95145008
Responsive ■ Resourceful ■ Reliable 14
has occurred, pavement subgrade areas should be reworked, moisture conditioned, and properly
compacted to the recommendations in this report immediately prior to paving .
4.7.2 Pavement Traffic
Traffic patterns and anticipated loading conditions were not available; however, typical pavement
sections with subgrade modification alternatives for 20 year design life are provided. These
represent a total of 45,000 18 -Kip Equivalent Single Axle Loads (ESALs) for Light Duty pavement
and 100,000 18-Kip ESALs for the Medium Duty pavement. The Light Duty pavement is intended
for passenger car and pickup trucks and occasional delivery trucks. The Medium Duty pavement
is intended for passenger car, pickup trucks, small delivery trucks, and occasional tractor trailer
trucks.
If the pavements are subject to heavier loading and higher traffic counts than the assumed values,
this office should be notified and provided with the information so that we may review these
pavement sections and make revisions if necessary.
4.7.3 Pavement Sections
Both asphalt and concrete pavement sections are pr esented in the following table. They are not
considered equal. Over the life of the pavement, concrete sections would be expected to require
less maintenance.
Pavement Section
Pavement Thickness, Inches
Light Duty
45,000 18-kip
ESALs
Medium Duty
100,000 18-kip
ESALs
Dumpster
Area
Portland Cement
Concrete
Concrete 5 6 7
Compacted Subgrade 6 6 6
*All materials should meet the TxDOT Standard Specifications for Highway Construction.
Geotechnical Engineering Report
Proposed Capital One Bank ■ Coppell, Texas
April 26, 2018 ■ Terracon Project No. 95145008
Responsive ■ Resourceful ■ Reliable 15
Pavement Section
Pavement Thickness, Inches
Light Duty
45,000 18-kip
ESALs
Medium Duty
100,000 18-kip
ESALs
Dumpster
Area
Full Depth
Asphaltic Concrete
Asphaltic Concrete
TxDOT Item 340
TxDOT Type D
2 2 -
Asphaltic Concrete
TxDOT Item 340
TxDOT Type A or B
3 4 -
Cement Modified Subgrade
TxDOT Item 275 6 6 -
*All materials should meet the TxDOT Standard Specifications for Highway Construction.
The concrete should have a minimum 28 -day compressive strength of 3,000 psi in Light Duty
areas and 3,500 psi in Medium Duty and dumpster areas. It should contain a minimum of 4.5±1.5
percent entrained air. As a minimum, the section should be reinforced with No. 3 bars on 18 -inch
centers in both directions. Refer to ACI 330 “Guide for Design and Construction of Concrete
Parking Lots” for additional information concerning joint spacing, joint depth, joint location, etc..
Pavements will be subject to differential movement due to heave in the site soils. Flat grades
should be avoided with positive drainage provided away from the pavement edges. Backfilling of
curbs should be accomplished as soon as practical to prevent ponding of water.
Openings in pavement, such as landscape islands, are sources for water infiltration into
surrounding pavements. Water collects in the islands and migrates into the surround ing subgrade
soils thereby degrading support of the pavement. This is especially applicable for islands with
raised concrete curbs, irrigated foliage, and low permeability near -surface soils. The civil design
for the pavements with these conditions shoul d include features to restrict or to collect and
discharge excess water from the islands. Examples of features are edge drains connected to the
storm water collection system or other suitable outlet and impermeable barriers preventing lateral
migration of water such as a cutoff wall installed to a depth below the pavement structure.
5.0 GENERAL COMMENTS
Terracon should be retained to review the final design plans and specifications so comments can
be made regarding interpretation and implementation of our geotechnical recommendations in the
design and specifications. Terracon also should be retained to provide observation and testing
services during grading, excavation, foundation construction and other earth -related construction
phases of the project.
Geotechnical Engineering Report
Proposed Capital One Bank ■ Coppell, Texas
April 26, 2018 ■ Terracon Project No. 95145008
Responsive ■ Resourceful ■ Reliable 16
The analysis and recommendations presented in this report are based upon the data obtained
from the borings performed at the indicated locations and from other information discussed in this
report. This report does not reflect variations that may occur be tween borings, across the site, or
due to the modifying effects of weather. The nature and extent of such variations may not become
evident until during or after construction. If variations appear, we should be immediately notified
so that further evaluation and supplemental recommendations can be provided.
The scope of services for this project does not include either specifically or by implication any
environmental or biological (e.g., mold, fungi, bacteria) assessment of the site or identification or
prevention of pollutants, hazardous materials or conditions. If the owner is concerned about the
potential for such contamination or pollution, other studies should be undertaken.
This report has been prepared for the exclusive use of our client for specific application to the
project discussed and has been prepared in accordance with generally accepted geotechnical
engineering practices. No warranties, either express or implied, are intended or made. Site
safety, excavation support, and dewatering requirements are the responsibility of others. In the
event that changes in the nature, design, or location of the project as outlined in this report are
planned, the conclusions and recommendations contained in this report shall not be considered
valid unless Terracon reviews the changes and either verifies or modifies the conclusions of this
report in writing.
APPENDIX A
FIELD EXPLORATION
1
Geotechnical Engineering Report
Proposed Capital One Bank ■ Coppell, Texas
April 26, 2014 ■ Terracon Project No. 95145008
Responsive ■ Resourceful ■ Reliable Exhibit A-2
Field Exploration Description
Subsurface conditions were explored by drilling ten borings to depths of about 5 to 25 feet at the
approximate locations indicated on the Boring Location Plan on Exhibit A-1 in Appendix A. Borings
B-1 through B-6 were drilled in 2014 and B -101 through B-104 were drilled in 2018. The test
locations were established in the field by measuring from available reference features and
estimating right angles. The boring location s should be considered accurate only to the degree
implied by the methods employed to determine them.
The borings were performed using a truck-mounted drill rig. Samples of the soils encountered in
the borings were obtained using thin-walled tube and split-spoon sampling procedures. The
samples were tagged for identification, sealed to reduce moisture loss, and taken to the laboratory
for further examination, testing, and classification.
Field logs of the borings were prepared by the drill crew. These logs include visual classifications
of the materials encountered as well as interpretation of the subsurface conditions between
samples. The boring log s included with this report represent the engineer’s interpretation of the
field logs and include modifications based on visual evaluation of the samples and laboratory test
results. The boring logs are presented on Exhibit A-3 through A-12 in Appendix A. General notes
to log terms and symbols are presented on Exhibit C-1 in Appendix C.
68
76
15
19
12
19
26-14-12
29-15-14
1.0 (HP)
3.0 (HP)
4.5+ (HP)
4.5+ (HP)
4.5+ (HP)
3.25 (HP)
2.0
4.0
13.0
15.0
FILL - SANDY LEAN CLAY (CL), dark brown, medium stiff
to stiff
FILL - SANDY LEAN CLAY (CL), brown, very stiff
SANDY LEAN CLAY (CL), gray and tan, hard
SANDY LEAN CLAY (CL), gray, very stiff
Boring Terminated at 15 FeetGRAPHIC LOGHammer Type: AutomaticStratification lines are approximate. In-situ, the transition may be gradual.THIS BORING LOG IS NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GEO SMART LOG-NO WELL 95145008_1 - CAPITOL ONE BANK COPPELL.GPJ TERRACON_DATATEMPLATE.GDT 4/27/18COMPRESSIVESTRENGTH(tsf)STRAIN (%)TEST TYPEPERCENT FINESWATERCONTENT (%)DRY UNITWEIGHT (pcf)LL-PL-PI
ATTERBERG
LIMITS
WATER LEVELOBSERVATIONSDEPTH (Ft.)5
10
15 SAMPLE TYPESTRENGTH TEST
FIELD TESTRESULTS SWC of Sandy Lake Rd. & S. Denton Tap Rd.
Coppell, Texas
SITE:
Page 1 of 1
Advancement Method:
Dry Auger
Abandonment Method:
Backfilled with auger cuttings
Notes:
Project No.: 95145008
Drill Rig:
Boring Started: 02-26-2018
BORING LOG NO. B-101
Levinson Alcoser Associates, LPCLIENT:
Houston, Texas
Driller: StrataBore
Boring Completed: 02-26-2018
Exhibit:A-9
See Exhibit A-3 for description of field procedures.
See Appendix B for description of laboratory
procedures and additional data (if any).
See Appendix C for explanation of symbols and
abbreviations.
PROJECT: Proposed Capital One Bank
2501 E Loop 820 N
Fort Worth, TX
No water encountered during drilling
Dry upon completion of drilling
WATER LEVEL OBSERVATIONS
DEPTH
LOCATION See Exhibit A-1
Latitude: 32.9688° Longitude: -96.9943°
49
59
14
16
19
33-16-17
40-16-24
1.0 (HP)
1.0 (HP)
0.25 (HP)
1.0 (HP)
4.5+ (HP)
2.5 (HP)
2.0
8.0
12.0
15.0
FILL - CLAYEY SAND (SC), with gravel, brown, loose to
medium dense
FILL - SANDY LEAN CLAY (CL), brown, soft to stiff
SANDY LEAN CLAY (CL), gray and brown, hard
SANDY LEAN CLAY (CL), gray, very stiff
Boring Terminated at 15 FeetGRAPHIC LOGHammer Type: AutomaticStratification lines are approximate. In-situ, the transition may be gradual.THIS BORING LOG IS NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GEO SMART LOG-NO WELL 95145008_1 - CAPITOL ONE BANK COPPELL.GPJ TERRACON_DATATEMPLATE.GDT 4/27/18COMPRESSIVESTRENGTH(tsf)STRAIN (%)TEST TYPEPERCENT FINESWATERCONTENT (%)DRY UNITWEIGHT (pcf)LL-PL-PI
ATTERBERG
LIMITS
WATER LEVELOBSERVATIONSDEPTH (Ft.)5
10
15 SAMPLE TYPESTRENGTH TEST
FIELD TESTRESULTS SWC of Sandy Lake Rd. & S. Denton Tap Rd.
Coppell, Texas
SITE:
Page 1 of 1
Advancement Method:
Dry Auger
Abandonment Method:
Backfilled with auger cuttings
Notes:
Project No.: 95145008
Drill Rig:
Boring Started: 02-26-2018
BORING LOG NO. B-102
Levinson Alcoser Associates, LPCLIENT:
Houston, Texas
Driller: StrataBore
Boring Completed: 02-26-2018
Exhibit:A-10
See Exhibit A-3 for description of field procedures.
See Appendix B for description of laboratory
procedures and additional data (if any).
See Appendix C for explanation of symbols and
abbreviations.
PROJECT: Proposed Capital One Bank
2501 E Loop 820 N
Fort Worth, TX
Water encountered at 6' during drilling
Dry upon completion of drilling
WATER LEVEL OBSERVATIONS
DEPTH
LOCATION See Exhibit A-1
Latitude: 32.9689° Longitude: -96.9941°
44
57
40
11
14
15
30-15-15
4.25 (HP)
0 (HP)
3.25 (HP)
3.5 (HP)
4.5+ (HP)
4.5+ (HP)
2.0
4.0
6.0
12.0
15.0
FILL - CLAYEY SAND (SC), with gravel, brown, dense
FILL - CLAYEY SAND (SC), brown, very loose
FILL - CLAYEY SAND (SC), brown and tan, medium dense
SANDY LEAN CLAY (CL), gray and brown, very stiff to hard
SANDY LEAN CLAY (CL), gray, hard
Boring Terminated at 15 FeetGRAPHIC LOGHammer Type: AutomaticStratification lines are approximate. In-situ, the transition may be gradual.THIS BORING LOG IS NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GEO SMART LOG-NO WELL 95145008_1 - CAPITOL ONE BANK COPPELL.GPJ TERRACON_DATATEMPLATE.GDT 4/27/18COMPRESSIVESTRENGTH(tsf)STRAIN (%)TEST TYPEPERCENT FINESWATERCONTENT (%)DRY UNITWEIGHT (pcf)LL-PL-PI
ATTERBERG
LIMITS
WATER LEVELOBSERVATIONSDEPTH (Ft.)5
10
15 SAMPLE TYPESTRENGTH TEST
FIELD TESTRESULTS SWC of Sandy Lake Rd. & S. Denton Tap Rd.
Coppell, Texas
SITE:
Page 1 of 1
Advancement Method:
Dry Auger
Abandonment Method:
Backfilled with auger cuttings
Notes:
Project No.: 95145008
Drill Rig:
Boring Started: 02-26-2018
BORING LOG NO. B-103
Levinson Alcoser Associates, LPCLIENT:
Houston, Texas
Driller: StrataBore
Boring Completed: 02-26-2018
Exhibit:A-11
See Exhibit A-3 for description of field procedures.
See Appendix B for description of laboratory
procedures and additional data (if any).
See Appendix C for explanation of symbols and
abbreviations.
PROJECT: Proposed Capital One Bank
2501 E Loop 820 N
Fort Worth, TX
No water encountered during drilling
Dry upon completion of drilling
WATER LEVEL OBSERVATIONS
DEPTH
LOCATION See Exhibit A-1
Latitude: 32.969° Longitude: -96.9943°
22
60
73
15
10
16
20
37-16-21
0 (HP)
0 (HP)
0 (HP)
0 (HP)
6-6-9
N=15
2.25 (HP)
6.0
8.0
12.0
15.0
FILL - CLAYEY SAND (SC), brown and orange, very loose
FILL - CLAYEY SAND (SC), with gravel, orange, very loose
SANDY LEAN CLAY (CL), gray, stiff to very stiff
SANDY LEAN CLAY (CL), tan and gray, very stiff
Boring Terminated at 15 FeetGRAPHIC LOGHammer Type: AutomaticStratification lines are approximate. In-situ, the transition may be gradual.THIS BORING LOG IS NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GEO SMART LOG-NO WELL 95145008_1 - CAPITOL ONE BANK COPPELL.GPJ TERRACON_DATATEMPLATE.GDT 4/27/18COMPRESSIVESTRENGTH(tsf)STRAIN (%)TEST TYPEPERCENT FINESWATERCONTENT (%)DRY UNITWEIGHT (pcf)LL-PL-PI
ATTERBERG
LIMITS
WATER LEVELOBSERVATIONSDEPTH (Ft.)5
10
15 SAMPLE TYPESTRENGTH TEST
FIELD TESTRESULTS SWC of Sandy Lake Rd. & S. Denton Tap Rd.
Coppell, Texas
SITE:
Page 1 of 1
Advancement Method:
Dry Auger
Abandonment Method:
Backfilled with auger cuttings
Notes:
Project No.: 95145008
Drill Rig:
Boring Started: 02-26-2018
BORING LOG NO. B-104
Levinson Alcoser Associates, LPCLIENT:
Houston, Texas
Driller: StrataBore
Boring Completed: 02-26-2018
Exhibit:A-12
See Exhibit A-3 for description of field procedures.
See Appendix B for description of laboratory
procedures and additional data (if any).
See Appendix C for explanation of symbols and
abbreviations.
PROJECT: Proposed Capital One Bank
2501 E Loop 820 N
Fort Worth, TX
No water encountered during drilling
Dry upon completion of drilling
WATER LEVEL OBSERVATIONS
DEPTH
LOCATION See Exhibit A-1
Latitude: 32.9687° Longitude: -96.9942°
APPENDIX B
LABORATORY TESTING
Geotechnical Engineering Report
Proposed Capital One Bank ■ Coppell, Texas
April 26, 2014 ■ Terracon Project No. 95145008
Responsive ■ Resourceful ■ Reliable Exhibit B-1
Laboratory Testing
The boring logs and samples were reviewed by a geotechnical engineer who selected soil
samples for testing. Tests were performed by technicians working under the direction of the
engineer. A brief description of the tests performed follows.
Liquid and plastic limit te sts, gradation tests and moisture content measurements were made to
aid in classifying the soils in accordance with the Unified Soil Classification System (USCS). The
USCS is summarized on Exhibit C-2 in Appendix C. Absorption swell tests were performed on
selected samples of the cohesive materials. These tests were used to quantitatively evaluate
volume change potential at in -situ moisture levels. Strength and consistency of cohesive soils
was determined by unconfined compression and hand penetrometer tests, respectively.
The results of the swell tests are presented in the following table. The gradation test results are
included in Appendix B-2. The results of the other laboratory tests are presented on the boring
logs in Appendix A.
Boring
No.
Depth
(feet)
Liquid
Limit
(%)
Plasticity
Index
(%)
Initial
Moisture
(%)
Final
Moisture
(%)
Surcharge
(psf)
Swell
(%)
B-1 2-4 31 18 17.4 18.5 370 0.0
B-1 8-10 - - 15.9 17.0 1,130 0.0
B-2 4-6 27 14 17.9 17.8 620 0.0
B-2 8-10 - - 14.3 15.6 1,120 0.0
B-3 4-6 - - 15.1 16.4 620 0.0
B-3 8-10 38 24 16.3 18.1 1,120 0.0
B-4 2-4 - - 20.0 21.2 370 0.2
B-4 6-8 33 19 15.6 17.7 870 0.0
APPENDIX C
SUPPORTING DOCUMENTS
Exhibit C-1
Exhibit C-2
UNIFIED SOIL CLASSIFICATION SYSTEM
Criteria for Assigning Group Symbols and Group Names Using Laboratory Tests A
Soil Classification
Group
Symbol Group Name B
Coarse Grained Soils:
More than 50% retained
on No. 200 sieve
Gravels:
More than 50% of
coarse
fraction retained on
No. 4 sieve
Clean Gravels:
Less than 5% fines C
Cu 4 and 1 Cc 3 E GW Well-graded gravel F
Cu 4 and/or 1 Cc 3 E GP Poorly graded gravel F
Gravels with Fines:
More than 12% fines C
Fines classify as ML or MH GM Silty gravel F,G, H
Fines classify as CL or CH GC Clayey gravel F,G,H
Sands:
50% or more of coarse
fraction passes
No. 4 sieve
Clean Sands:
Less than 5% fines D
Cu 6 and 1 Cc 3 E SW Well-graded sand I
Cu 6 and/or 1 Cc 3 E SP Poorly graded sand I
Sands with Fines:
More than 12% fines D
Fines classify as ML or MH SM Silty sand G,H,I
Fines Classify as CL or CH SC Clayey sand G,H,I
Fine-Grained Soils:
50% or more passes the
No. 200 sieve
Silts and Clays:
Liquid limit less than 50
Inorganic: PI 7 and plots on or above “A” line J CL Lean clay K,L,M
PI 4 or plots below “A” line J ML Silt K,L,M
Organic: Liquid limit - oven dried 0.75 OL Organic clay K,L,M,N
Liquid limit - not dried Organic silt K,L,M,O
Silts and Clays:
Liquid limit 50 or more
Inorganic: PI plots on or above “A” line CH Fat clay K,L,M
PI plots below “A” line MH Elastic Silt K,L,M
Organic: Liquid limit - oven dried 0.75 OH Organic clay K,L,M,P
Liquid limit - not dried Organic silt K,L,M,Q
Highly organic soils: Primarily organic matter, dark in color, and organic odor PT Peat
A Based on the material passing the 3-in. (75-mm) sieve
B If field sample contained cobbles or boulders, or both, add “with cobbles
or boulders, or both” to group name.
C Gravels with 5 to 12% fines require dual symbols: GW -GM well-graded
gravel with silt, GW -GC well-graded gravel with clay, GP-GM poorly
graded gravel with silt, GP-GC poorly graded gravel with clay.
D Sands with 5 to 12% fines require dual symbols: SW -SM well-graded
sand with silt, SW -SC well-graded sand with clay, SP-SM poorly graded
sand with silt, SP-SC poorly graded sand with clay
E Cu = D60/D10 Cc =
6010
2
30
DxD
)(D
F If soil contains 15% sand, add “with sand” to group name.
G If fines classify as CL-ML, use dual symbol GC-G M, or SC-SM.
H If fines are organic, add “with organic fines” to group name.
I If soil contains 15% gravel, add “with gravel” to group name.
J If Atterberg limits plot in shaded area, soil is a CL-ML, silty clay.
K If soil contains 15 to 29% plus No. 200, add “with sand” or “with
gravel,” whichever is predominant.
L If soil contains 30% plus No. 200 predominantly sand, add “sandy”
to group name.
M If soil contains 30% plus No. 200, predominantly gravel, add
“gravelly” to group name.
N PI 4 and plots on or above “A” line.
O PI 4 or plots below “A” line.
P PI plots on or above “A” line.
Q PI plots below “A” line.