CF-Justice Center Fence-SP060120/'`
GEOTECHNICAL EXPLORATION
on
COPPELL TOWN CENTER PLAZA
Off Town Center near Parkway Boulevard
Coppell, Texas
ALPHA Report No. G051198
Prepared for:
HALFF ASSOCIATES, INC.
8616 Northwest Plaza Drive
Dallas, Texas 75225
Attention: Mr. Francois De Kock
January 20, 2006
Prepared By:
ALPHA TESTING, 1NC.
2209 Wisconsin Road, Suite 100
Dallas,l'exas 75229
~~,,.
ALPHA TESTING, INC.
2209 ~sconsir? St., Suite 1 Gb
DaNas Texas 75229
972/620-8911 - 972/263-4937 (Metro)
FAX: 972/408023
January 20, 2006
Halff Associates, Inc.
861E Northwest Plaza Drive
Dallas, Texas 75225
Attention: Mr. Francois De Kock
Re: Geotechnical Exploration
Coppell Town Center Plaza
Off Town Center near Parkway Boulevard
Coppell, Texas
ALPHA Report No. G051198
Attached is the report of the geotechnical exploration performed for the project referenced above.
This study has been authorized by Mr. Luny Hughes on December 1, 2005 and performed in
accordance with ALPHA Proposal No. GT 16854A dated November 1, 2005.
This report contains results of field explorations and laboratory testing and an engineering
interpretation of these with respect to available project characteristics. The results and analyses
have been used to develop recommendations to aid design and construction of foundations.
ALPHA TESTING, INC. appreciates the opportunity to be of service on this project. If we can
be of further assistance, such as providing materials testing services during construction, please
contact our office.
Sincerely yours,
ALPIIA TESTING, INC.
k ar, _.
Harsha Addula
Project Manager
. ow , P.E.
i
Vice President ~
HVA/BAP/har
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TABLE OF CONTENTS
On
ALPIIA REPORT NO. G051198
1.0 PURPOSE AND SCOPE .................................................................................................. ..1
2.0 PROJECT CHARACTERISTICS .................................................................................... ..1
3.0 IjIELD EXPLORATION .................................................................................................... ..2
4.0 LABORATORY TESTS .................................................................................................... ..2
5.0 GENERAL SUBSURFACE CONDI'TIONS ..................................................................... ..2
6.0 DESIGN RECOMMENDATIONS .......................................... . . . • - - - ......... - - - - - .. ..3
6.1 Piers ............................................................................................. .3
6.2 Slab-0n-Grade (Stage Area-Amphitheater) ............................................... .5
6.3 Pond ............................................................................................ ..6
6.4 Retaining and I3~low-Cmade Walls ......................................................... ..7
6.5 Footings -Retaining Walls ................................................................. ..8
6.6 Drainage ...................................................................................... ..9
7.0 GENERAL CONSTRUCTION PROCEDURES AND RECOMMENDATIONS............ 11
7.1 Site Preparation and Grading ................................................................. 11
7.2 Foundation Excavations ..................:.................................................. 12
7.3 Fill Compaction ................................................................................ 13
7.4 Groundwater .................................................................................. 14
8.0 LIlviTTATIONS ...... . . . ................................................................................ 14
i
APPENDIX
A-1 Methods of Field Exploration
Boring Location Plan -Figure 1
B-1 Methods of Laboratory Testing
Swell Test Data -Figure 2
Record of Subsurface Exploration
_ __
Classifications
Key to Soil Symbols and
_
_ _ _ _
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ALPHA Report No. 6051198 ~j~,
1.0 PURPOSE AND SCOPE
The purpose of this geotechnical exploraatian is to evaluate -some of the physical and engineering
properties of subsurface materials at the subject site with respect to formulation of appropriate
geotechnical design parameters for the proposed construction. The field exploration has been
accomplished by sec~.uing subsurface samples from widely spaced test borings performed at the
proposed site. Engineering analyses have been performed from results of the field exploration
and results of Laboratory tests performed on representative samples.
Also included are general comments pertaining to reasonably anticipated construction problems
and recommendations concerning earthwork and quality control testing during construction. This
information can be used to evaluate subsurface conditions and to aid in ascertaining construction
meets project specifications.
Recommendations provided in this report have been developed from information obtained in test
borings depicting subsurface conditions only at the specific boring locations and al the particular
time designated on the logs. Subsurface conditions at other locations may differ from those
observed at the boring locations. The scope of work may not fully define the variability of
subsurface materials that is present on the site.
The nature and extent of variations between borings may not become evident until construction.
If significant variations then appear evident, our office should be contacted to re-evaluate our
recommendations after performing on-site observations. and possibly other tests.
2.0 PROJECT C1iARA.CTERISTICS
It is proposed to construct a new amphitheater, a 70-ft high concrete/masonry tower, a pond and a
pond overlook for the planned Coppell Town Center Plaza on a site located east of the existing
Justice Cater located off Town Center Boulevard and south of the existing Coppell Town
Center in Coppell, Texas. A site plan illustrating the general outline of the property is provided
as Figure 1, the Boring Location Plan, in the Appendix of this report. At the time the field
exploration was performed, most of the site. was covered with grass. Some underground utilities
were noted in the southern portion of the site. According to the grading plan prepared by Halff
Associates, Inc. (Project No. 22831 dated 12/2!05; Sheet No. C2.01), the overall site slopes
downward generally to the southeast with a maximum change in surface elevation of about 5 ft
(Elev. 468 to 463).
Present plans provide for the construction of a new amphitheater, a 70-ft high concrete/masonry
tower, a pond and pond overlook. In addition, ancillary structures such as canopies, underground
vault, retaining walls, entry structures etc. are planned for the proposed projectr
ALPHA Report No. G051198 ~~~~
3.0 FIELD EXPLORATION
Subsurface conditions on the subject site have been explored by drilling a total of four (4) test
borings in general accordance with ASTM D 420 to a depth of up to 50 ft using standard rotary
drilling equipment. The approximate locations of each test boring aze shown on the Boring
Location Plan, Figure 1, enclosed in the Appendix of this report. Details of drilling and sampling
operations are briefly summarized in Methods of Field Exploration, Section A-1 of the
Appendix.
Subsurface types encountered during the field exploration aze presented on Record of Subsurface
Exploration sheets included in the Appendix of this report. The boring logs contain our Field
Technician's and Engineer's interpretation of conditions believed to exist between actual samples
retrieved_ Therefore, these boring logs contain both factual and interpretive information. Lines
delineating subsurface strata on the boring logs are approximate and the actual transition between
strata maybe gradual.
Fill and/or possible fill soils were observed to depths of about 6 to 8 fl in Borings 1, 3 and 4.
There may be fill in other borings or at other locations, but could not be readily identified.
Composition of the fill has been evaluated based on samples retrieved from 6-inch maximum
diameter boreholes. It is anticipated this fill was placed and compacted during development of
the existing facilities.
4.0 LABORATORY TESTS
Selected samples of the subsurface materials have been tested in the laboratory to evaluate their
engineering properties as a basis in providing recommendations for foundation design and
earthwork construction. A brief description of testing procedures used in the laboratory can be
found in Methods of Laboratory Testing, Section B-1 of the Appendix. Individual test results aze
presented on Record of Subsurface Exploration sheets or on summary data sheets also enclosed
in the Appendix.
5.0 GENERAL SUBSURFACE CONDITIONS,
Within the 54-ft maximum depth explored on the site, subsurface materials consist generally of
hard dry sandy clay (CL) underlain by clay shale and deeper shale. In addition, silty clay was
noted in Boring 2. However, shale was not encountered within the maximum 20-ft depth
explored in Boring 4. The upper 6 to 8 ft of subsurface material is fill or possible fill. The letters
in parenthesis represent the soils' classification according to the Unified Soil Classification
System (ASTM D 248. More detailed stratigraphic information is presented on the Record of
Subsurface Exploration Sheets attached to this report.
ALPHA Report No. G051198
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Most of the subsurface materials are relatively impermeable and are anticipated to have a
relatively slow response to water movement. However, the gravel and sand seams encountered
within the clayey soils are relatively permeable and are anticipated to have a relatively more rapid
response to water movement. Therefore, several days of observation will be required to evaluate
actual groundwater levels within the depflrs explored. Also, the groundwater level at the site is
anticipated to fluctuate seasonally depending on the amount of rainfall, prevailing weather
conditions and subsurface drainage characteristics.
During field explorations, groundwater was noted on drilling tools and in open boreholes upon
completion in all borings at depths of about 8 to 15 ft as measured from existing grade. It is
common to detect seasonal groundwater either from natural fractures within the clayey
matrix, near the soiVrock (shale) interface or from fractures in the rock, particularly after a wet
season.
Further details concerning subsurface materials and conditions encountered can be obtained from
the Record of Subsurface Exploration sheets provided in the Appendix of this report.
6.0 DESIGN RECOMMENDATIONS
The following design recommendations have been developed on the basis of the previously
described project Characteristics (Section 2.0) and General Subsurface Conditions (Section 5.0).
If project criteria should change, including location of proposed structures, our office should
conduct a review to determine if modifications to the recommendations are required. Further, it
is recommended our office be provided with a copy of the final plans and specifications for
review prior to construction.
The following design criteria given in this report have been developed assuming the planned
structures/pond are constructed at final grades as shown on the grading plan prepared by
Halff Associates, Inc. (Project No. 22831 dated 12/2/05; Sheet No. C2.01). Further cutting and
filling on the site beyond that indicated on the grading plan referenced above can alter the
recommended foundation design parameters. Therefore, it is recommended our office be
contacted before performing other cutting and filling on site to verify the appropriate design
parameters are utilized for final foundation_desiga.
6.1 Piers
Our findings indicate the proposed structures (70-ft tower, canopies, entry structures and
pond overlook) could be supported using a system of drilled, straight-shaft piers. Based
on subsurface conditions encountered in the borings, the gray shale is present in Borings
1-3 at depths varying from about 19 to 21 ft below existing grade. Gray shale was not
encountered within the 20 ft depth explored in Boring 4, but is expected near the boring
termination depth.
Straight-shaft piers should be brought to bear at least 3 ft into the underlying gray shale.
Piers bearing at least 3 ft into the gray shale can be dimensioned using a net allowable
end-bearing pressure of 18 kips per sy ft and skin friction (in compression) of 1.8 kips per
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ALPHA Report No. G051198
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sq ft. The skin friction component should be applied only to the portion of the shaft
located in the gray shale (neglecting the upper 3 ft of gray shale) and below any
temporary casing. The above bearing capacity contains a factor of safety of at least 3
considering a general bearing capacity failure and the skin friction value has a factor of
safety of at least 2. Normal elastic settlement of the pier under loading is estimated at
less than about 1 inch.
Each pier should be designed to resist the uplift pressure (soil-to-pier adhesion) due to
potential soil swell along the shaft from post construction heave and other uplift forces
applied by structural loadings. The magnitude of uplift adhesion due to soil swell along
the pier shaft cannot be defined accurately and can vary according to the actual in-place
moisture content of the soils during construction. It is estimated this uplift adhesion
will not exceed about 1.25 kips per sq ft. This soil adhesion is approximated to act
uniformly over the upper 10 ft of the pier shaft in contact with clayey soils.
The uplift resistance of each pier can be computed using an allowable skin fi-iction value
of 1.5 kips per sq ft acting uniformly over the portion of the shaft bearing in the gray
shale. The top 3 ft of gray shale should be neglected in computing the uplift resistance of
each pier. This uplift resistance value has a factor of safety of at least 2.
Lateral loads imposed on pier foundations for the structures can be resisted by passive
resistance in the underlying clayey soils and gray shale. An ultimate passive resistance of
4 ksf can be considered for the overburden clayey soils, with an ultimate passive
resistance of 12 ksf can be considered for the gray shale. These values are ultimate values
and the structural engineer should incorporate the appropriate factor of safety during
design (minimum of 2). Further, the above resistance values could be applied uniformly
over the face of the drllled pier shaft. The lateral resistance of the top portion of the pier
shafts (portion within 6 ft of final grade) should be neglected due to disturbance.
Foundation elements in contact with the site clayey soils between piers will be subjected
to upward movements on the order of about 1.5 to 3 inches. If this level of movement is
considered excessive, a minimum 6-inch void space should be provided beneath the
bottom of the foundation elements.or any pier caps. Commercially available cardboazd
box forms (cartons) aze made for this purpose. The cardboard cartons should extend the
full length and width of the pier cap. Prior to concrete placement, the cartons should be
inspected to verify they are firm, properly placed, and capable of supporting wet concrete.
Some type of permanent soil retainer, such aspre-cast concrete panels, must be provided
to prevent soils adjacent to the pier cap from sloughing into the void space.
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ALPHA Report No. G051198 ~j~,
6.2 Slab-on-grade (Stake Area -Amphitheater)
Our Endings indicate the stage area in the vicinity of Boring 2 could be designed with
exterior and interior grade beams adequate to provide sufficient rigidity to the foundation
system. A net allowable bearing pressure of 2 kips per sq ft may be used for design of all
grade beams bearing on either natural undisturbed soil or new fill soil placed as
recommended in Section 7.3 of this report. Grade beams should bear a minimum depth
of 12 inches below final grade and should have a minimum width of 10 inches.
To reduce cracking as normal movements occur in foundation soils, all grade beams and
the slab should be adequately reinforced with steel (conventional reinforcing steel). It is
common to experience some minor cosmetic distress to structures with slab-on-grade
foundation systems due to normal ground movements. A properly designed and
constructed moisture barrier should be placed between the slab and subgrade soils to
retard moisture migration through the slab.
The slab-on-grade foundation for the new stage area could experience soil-related
potential seasonal movements on the order of up to about 3 inches if constructed at the
proposed final grade as shown on the grading plan prepared by Halff Associates, Inc.
(Project No. 22831 dated 12/2!05; Sheet No. C2.01) while foundations for the
underground vault planned at the southwest comer of the existing Town Center building
constructed at a depth ~of about 5 to 8 ft below existing grade could experience soil-
related potential seasonal movements of up to about i inch If 3 inches of movement is
considered excessive for the stage area, movement of the slab~n-grade can be reduced to
about 1 inch by placing a minimum 3 ft of select non-expansive material beneath the slab.
In choosing this method of movement reduction, the Owner is accepting some post
construction movement (about 1 inch).
1. All non-expansive material or replacement soil should consist of a select
material having a liquid limit less than 35 and a plasticity index (PI) not less
than about 4 nor greater than 15.
2. Select material should be compacted to at least 95 percent of standard Proctor
maximum dry density (ASTM D 698) and within the range of 1 percentage
point below to 3 percentage points above the material's optimum moisture
content.
3. Slab constructed on at least 3 ft of select, non-expansive material could
experience potential movements of about 1 inch.
Should new non-select material be placed, the potential seasonal movements indicated
above may increase and a re-evaluation of the recommendations will be required by our
office. Therefore, it is preferable any new fill material be select, non-expansive material
as described in Section 7.3 of this report.
ALPHA Report No. G051198
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The above potential seasonal movements have been estimated using results of absorption
swell tests, in general accordance with methods outlined by Texas Highway Department
Test Method Tex-124-E and engineering judgement and experience. Estimated
movements have been calculated assuming the moisture content of the in-situ soil within
the normal zone of seasonal moisture content change varies between the "dry" condition
and a "wet" condition as defined by Tex-124-E. Also, it was assumed a 1 psi surcharge
load from the floor slabs acts on the subgrade soils. Movements excc~ding those
predicted above could occur if positive drainage of surface water is not maintained or if
soils are subject to an outside water source, such as leakage from a utility line or
subsurface moisture migration from ofd=site locations.
6.3 Pond
Current plans provide for the pond to be up to about 14 ft deep. The existing soils in the
pond areas are composed of sandy clay with gravel and sand, and seepage through these
soils in the bottom and sides of the pond could be significant. Therefore, it is
recommended a clay liner (soils with a plasticity index of 30 or greater and a liquid limit
of at least 50) be placed over all exposed soils to reduce seepage losses: The clay liner
should be at least 2 ft thick.
The plasticity index and liquid limit of material used as a liner should be routinely
verified during placement using laboratory tests. Visual observation and classification
should not be solely relied upon to confirm the material to be used as a liner satisfies the
above Atterberg-limit cxiteria. Based on conditions encountered in the widely spaced
borings, the liner material would not generally be presart on-site and materials used for
the liner would need to be imported. A plastic or polyethylene loner could also be
considered in lieu of a clay liner.
Following excavation and prior to placement of any liner material, it is recommended the
exposed sandy clay material in the pond bottom and sides be scarified to a depth of at
least 8 inches and re-compacted (re-processed) prior to placing a clay liner. The
re-processed sandy clay soil and clay liner materials should be compacted to at least
90 percent of standard Proctor maximum dry density (ASTM D 698). The compacted
moisture content of the sandy clay and clay liner materials during placement should be
within the range of 2 to 5 percentage points above optimum. Liner materials should be
processed such that the largest particle or clod is less than 3 inches prior to compaction.
Following placement of the clay liner, the liner should not be allowed to dry excessively.
The clay liner should be maintained in a moist condition (even during periods when the
pond is drained for maintenance) to prevent development of shrinkage cracks in the liner
material. Past problems have occurred with clay liners when shrinkage cracks were
allowed to form and the cracks became filled with fine sand. The sand prevented
resealing of the shrinkage cracks and significant seepage occurred through the liner.
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ALPHA Report No. G051198
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Groundwater was encountered at depths of about 7 to 13 ft in the vicinity of the proposed
pond. Well points or other conventional de-watering equipment may be required to
de-water the pond excavations.
Detailed slope stability analysis for the planned side slopes was beyond the scope of the
study, however, based on our previous experience with similar soils, typically side slopes
of 3 (horizontal) to 1 (vertical) should be considered stable long-term for embankment
heights up to 10 ft. Higher embankments would require flatter slopes of about
4 (horizontal) to 1 (vertical). ALPHA Testing, Inc. should be contacted for slope stability
of the planned slopes prior to construction.
6.4 Retaining and Below-Grade Walls
Retaining walls and below-grade walls for the proposed vault at this site should be
designed to resist the expected lateral earth pressures. The magnitude of lateral earth
pressure against retaining and underground walls is dependent on the method of backfill
placement, type of backfill soil, drainage provisions, and type of wall (rigid or yielding)
after placement of the backfill. Experience demonstrates when a wall is held rigidly
against horizontal movement (restrained at the top), the lateral pressure (at-rest lateral
earth pressure) against the wall is greater than the normally assumed active pressure_
Yielding walls (rotation at the top of the wall on the order of 0.1 to 0.4 percent of the wall
height) can be designed for active earth pressures (k,) but rigid walls should be designed
for higher at-rest lateral earth pressures (ko). Walls associated with the structures should
be considered rigid. Walls should be designed using the equivalent fluid pressures
provided in Table A, considering a triangular distribution and assuming a level ground
surface behind the wall. The equivalent fluid pressures provided do not include a factor
of safety.
TABLE A
LATERAL EARTH PRESSURE
Equivalent Fluid Pressure,
cf
Undrained
Material Condition Drained Including
Hydrostatic
Pressure
At-Rest, lca=fl.45 59 93
Frce Draining Granular Soil
' Active, ka~.3 39 83
435
, YT =130 pcf Passive, kP=3.7 480 312
Site Sandy Clays, At-Rest, ka~.75 -- 106
Q}=16', YT =120 pcf Active, ka~.6 -- 97
Passive, kP=1.8 -- 166
ALPHA Report No. G051198 ~~~~
Notes: Free Draining Granular Ball
This material should be a clean, relatively well-graded granulaz soil consisting of either a
' ~ sand or a sand and gravel mixture (less than 10 percent finer than the No. 200 sieve size).
To reduce surface water seepage into the free draining backfill, the top 1-ft of the backfill
• should consist of on-site clay soil with a plasticity index of at least 25. The granular
backfill should extend upward and outward from the base of the wall on a 1 (horizontal)
to 1 (vertical) slope. The granular ball should be separated from the adjacent native
soils using a filter fabric (Mirafi 140N, or equivalent) to prevent intrusion of native soils
into the granulaz backfill.
Complete drainage of the frce draining material could be provided to prevent the
development of hydrostatic pressures behind the wall. Atypical drainage system could
consist of perforated plastic PVC pipes placed in filter trenches excavated pa_ra11e1 to the
base of the walls for their entire •length. The drain pipes should be positioned at a depth
lower than the bottom elevation of the wall and should also be wrapped with filter fabric
(Mirafi 140N, or equivalent). A drainage system is beneficial regardless of the type of
backfill used. As a minimum, weep holes should be provided for freestanding site walls.
Settlement of backfill behind the walls should be anticipated. Even though backfill is
properly compacted as recommended in Section 7.3 of this report, the fill is still subject
to settlements over time of up to about 1 to 2 percent of the total fill thiclrness.
The effects of surcharge loading must also be considered. The applicable coefficient of
earth pressure should also be assumed for this case. Lightweight, hand-controlled
vibrating plate compactors are recommended for compaction of backfill adjacent to walls
to reduce the possibility of increases in lateral pressures due to over-compaction. Heavy
compaction equipment should not be operated near the walls. Also, compaction of
backfill soils behind walls should not exceed 100 percent standard Proctor maximum dry
density (ASTM D 698) to further limit lateral earth pressures against walls.
As a minimum a properly designed and constructed moisture bamer should be placed
betwcen the slab and subgrade to retard moisture migration through the slab.
6.5 Footings - Retaining Walls
The retaining walls could be supported using a shallow footing foundation system.
Footings can be designed using a net allowable bearing pressure of 2 kips per sq ft for
wall (strip type) footings bearing in either natural undisturbed soil or new fill soil placed
as outlined in Section 7.3. In using net pressures,-the weight of the footing and backfill
over the footing need not be considered. All footings for retaining walls should be
located at a depth of at least 1.5 ft below final exterior grade as measured adjacent to the
bottom of the retaining wall. _Wall footings should have a least dimension of 18 inches in
width for bearing capacity considerations.
ALPHA Report No. G051198
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It is estimated the resulting total foundation movements could experience movements of
about 1.5 to 3 inches. These potential movements have been estimated in general
accordance with methods outlined by Texas Highway Department Test Method Tex-124-
E and engineering judgment and experience. Estimated movements have been calculated
assuming the moisture content of the in-situ soil within the normal zone of seasonal
moisture content change varies between the "current" condition and a "wet" condition as
defined by Tex-124-E. ~ Also, it was assumed a 1 psi surchazge load from the floor slab
acts on the subgrade soils. Movements exceeding those predicted above could occur if
positive drainage of surface water is not maintained or if soils are subject to an outside
water source, such as leakage from a utility line or subsurface moisture nugration from
off-site locations. Differential movements should not exceed about 75 percent of the
predicted total movement. Careful field inspection of footing excavations will contribute
substantially to reducing foundation movements.
Careful monitoring during construction is necessary to locate any pockets or seams of
unsuitable materials, which might be encountered in excavations for footings. These
materials, if found, should be removed and replaced with lean concrete (about 2,000 psi
strength at 28 days).
Resistance to sliding will be developed by friction along the base of the footings and
passive earth pressure ailing on the vertical face of the footing and a key installed in the
base of the footings, if required. It is recommended a coefficient of base friction of
0.35 be used along the bottom of the footing. The available passive earth resistance on
the vertical face of the footing and a key constructed in the base of the footing may be
calculated using an allowable passive earth pressure of 750 psf.
6.6 Drainage
Adequate draiaage should be provided to reduce seasonal variations in moisture content
of foundation soils. All pavement and sidewalks within 5 ft of the structures should be
sloped away from the residences to prevent goading of water around the foundations.
Final grades within 5 ft of the structures should be adjusted to slope away from the
structures at a minimum slope of 2 percent. Maintaining positive: surface drainage
throughout the life of the structures is essential.
hi areas with pavement or sidewalks adjacent to the new structures, a positive seal must
be maintained between the structures and the pavement or sidewalk to minimize seepage
of water into the underlying supporting soils. Post-construction movement of pavement
and flat-work is common. Normal maintenance should include examination of all joints
in paving and sidewalks, etc. as well as resealing where necessary.
Several factors relate to civil and architectural design and/or maintenance, which can
significantly affect future movements of the foundation and floor slab systems:
1. Preferably, a complete system of gutters and downspouts should carry runoff
water a minimum of S feet from the completed structures.
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ALPHA Report No. G051198
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2. Large trees and shrubs should not be allowed closer to the foundations than a
1 horizontal distance equal to roughly one-half of their mature height due to
,' their significant moisture demand upon maturing.
3. Moisture conditions should be maintained "constant" around the edge of the
slabs. Pending of water in planters, in unpaved areas, and around joints in
paving and sidewalks can cause slab movements beyond those predicted in
this report.
4. Planter box structures placed adjacent to buildings should be provided with a
means to assure concentrations of water are not available to the subsoil
stratigraphy.
~ S. Finally, architectural design of the floor slabs should avoid additional features
such as wing walls as extensions of the slabs.
j Trench backfill for utilities should be properly placed and compacted as outlined in
Section 7.3 of this report and in accordance with requirements of local City standards.
~ Since granular bedding backfill is used for most utility lines, the backf~lled trench should
not become a conduit and allow access for surface or subsurface water to travel toward
the new structures. Concxete cut-0ff collars or clay plugs should be provided where
I utility lines cross building lines to prevent water from traveling in the trench backf~ll and
i entering beneath the structures.
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ALPHA Report No. GO51 198 ~~~~
7.0 GENERAL CONSTRUCTION PROCEDURES AND RECOMMENDATIONS
Variations in subsurface conditions could be encountered during construction. To pemut
correlation between test boring data and actual subsurface conditions encountered during
construction, it is recommended a registered Professional Engineering firm be retained to observe
construction procedures and materials.
Some construction problems, particularly degree or magnitude, cannot be anticipated until
the course of construction. The recommendations offered in the following paragraphs are
intended, not to limit or preclude other conceivable solutions, but rather to provide our
observations based on our experience and understanding of the project characteristics and
' subsurface conditions encountered in the borings.
7.1 Site Preparation and Grading
All areas supporting the foundations or areas to receive fill should be properly prepared.
After completion of the necessary stripping, clearing, and excavating and prior to
placing any required fill, the exposed subgrade should be carefully evaluated by
probing and testing. Any undesirable material (organic material, wet, soft., or
loose soil) still in place should be removed.
The exposed subgrade should be further evaluated by proof-rolling with a heavy
pneumatic tired roller, loaded dump thick or similar equipment weighing
approximately 10 tuns to check for pockets of soft or loose material hidden
beneath a thin crust of possibly better soil.
Proof-rolling procedures should be observed routinely by a Professional
Engineer, or his designated representative.
Any undesirable material (organic material, wet, soft, or loose soil) exposed
should be removed and replaced with well-compacted material as outlined in
Section 7.3.
Prior to placement of any fill, the exposed subgrade should then be scarified to a
minimum depth of 6 inches and recompacted as outlined in Section 7.3.
Slope stability analysis of embankments (natural or constructed) was not within the scope
of this study. Trench excavations should be braced or cut at stable slopes in accordance
with Occupational Safety and Health; Administration (OSHA) requirements, .Title
29, Items 1926.650-1926.653 and other applicable building codes.
Due to clayey soils found near the surface, traffic of heavy equipment (including heavy
compaction equipment) may create pumping and general deterioration of shallow soils.
Therefore, some construction difficulties should be anticipated during periods when these
soils are saturated.
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ALPHA Report No. GOS 1198
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7.2 Foundation Excavations
All foundation excavations should be monitored to verify foundations' bear on suitable
material. The bearing stratum exposed in the base of all foundation excavations
should be protected against any detrimental change in conditions. Surface runoff water
should be drained away from excavations and not allowed to collect. All concrete
for foundations should be placed as soon as practical after the excavation is made.
Preferably, drilled piers should be excavated and concrete placed within 8 hours after the
design penetration into the gray shale is begun.
Prolonged exposure of the bearing surface to air or water will result in changes in strength
and compressibility of the bearing stratum. Therefore, if delays occur, excavations
should be slightly deepened and cleaned, in order to provide a fresh bearing surface.
All pier shafts should be at least 1.5 ft in diameter to facilitate clean-out of the base
- and proper monitoring. Concrete placed in pier holes should be directed through a
tremie, hopper, or equivalent. Placement of concrete should be vertical through the
center of the shaft without hitting the sides of the pier or reinforcement to reduce the
possibility of segregation of aggregates. Concrete placed in piers should have a minimum
slump of S inches (but not greater than 7 inches) to avoid potential honey-combing.
Observations during pier drilling should include, but not necessarily be limited to, the
following items:
Verification of proper bearing strata and consistency of subsurface stratification
with regard to boring logs,
Confumation the minimum required penetration into the bearing strata is
achieved,
Complete removal of cuttings from bottom of pier holes,
Proper handling of any observed water seepage and sloughing of subsurface
materials,
No more than 2 inches of standing water should be permitted in the bottom of pier
holes prior to placing concrete, and
Verification of pier diameter and steel reinforcement.
According to subsurface conditions observed in the borings, casing will be necessary to
control water seepage during installation of the straight-shaft piers. As casing is
extracted, care should be taken to maintain a positive head of plastic concrete and
minimize the potential for intrusion of water seepage. Groundwater can also occur within
fractures of the bearing stratum and this may require extending the casing and deepening
the piers. If groundwater cannot be controlled by the use of casing, underwater placement
12
ALPHA Report No. GOS I 198
?\
of pier concrete may be required Special mix designs are usually required for tremied or
pumped concrete. Proper concreting procedures should include placement of concrete
from the bottom to the top of the pier using a sealed tremie or pumped concrete. The
tremie should be maintained at least S ft into the wet concrete during placement. It is
recommended a separate bid item be provided for casing and underwater concrete
placement on the contractors' bid schedule.
7.3 Fill Compaction
Materials used as select, non-expansive material in building pad areas should have a
liquid limit less than 35, a plasticity index (Pl) not less than about 4 nor greater
than 1 S and contain no more than 0.5 percent fibrous organic materials, by weight. All
select material should contain no deleterious material and should be compacted to a dry
density of at least 95 pecrexit standard Proctor maximum dry density (ASTM D 698) and
within the range of 1 percentage point below to 3 percentage points above the material's
optimum moisture content. (Note: The plasticity index and liquid linut of material used
as select non-expansive material should be routinely verified during placement using
laboratory tests. Visual observation and classification should not be relied upon to
confirm the material to be used as select, non-expansive material satisfies the above
Atterbc:rg-limit criteria.)
Sandy materials with a plasticity index below 25 should be compacted to a dry density of
at least 95 percent of standard Proctor maximum dry density (ASTM D 698) and within
the range of 1 percentage point below to 3 percentage points above the material`s
optimum moisture content.
Clay soils with a plasticity index equal to or greater than 25 should be compacted to a dry
density betwcen 93 and 98 percent of standard Proctor maximum dry density
(ASTM D 698). The compacted moisture content of the clays during placement should
be within the range of 2 to 5 percentage points above optimum. Clay 611 should be
processed and the largest particle or clod should be less than 6 inches prior to
compaction.
Compaction should be accomplished by placing fill in about 8-inch thick loose lifts and
compactutg each Lift to at least the specified minimum dry density. Field density and
moisture content tests should be performed oa each lift. As a guide, one test per
2,500 sq ft per lift is recommended in building areas. In lazger site areas, a test frequency
of one test per 5,000 sq ft or greater per lift maybe used. Utility trench backfill should be
tested at a rate of one test per lift per each 3001ineal feet of trench.
t~
ALPHA, Report No. G051198
7_4 Groundwater
As previously discussed temporary casing will be required during installation of the
straight-shaft piers. Groundwater can also occur within fractures of the bearing stratum
and this may require extending the casing and deepeiring the piers. If groundwater cannot
be controlled by the use of casing, underwater placement of pier concrete may be
required.
8.0 LIMITATIONS
Professional services provided in this geoterhnical exploration have been performed, findings
obtained, and recommendations prepared in accordance with generally accepted geotechnical
engineering principles and practices. The scope of services provided herein does not include an
environmental assessment of the site or investigation for the presence or absence of hazardous
materials in the soil, surface water or groundwater.
ALPHA TESTING, INC. is not responsible for conclusions, opinions or recommendations made
by others based on this data. Information contained in this report is intended for exclusive use of
the Client (and their design representatives) and design of specific structures outlined in
Section 2.0. Recommendations presented in this report should not be used for design of any
other structure except that specifically described in this report. Further, subsurface conditions can
change with passage of time. Recommendations contained herein arc not considered applicable
for an extended period of time after the completion date of this report. It is recommended our
office be contacted for a review of the contents of this report for construction commencing more
than one (1) year after completion of this report.
Recommendations provided in this report are based on our understanding of information
provided by the Client about characteristics of the project. If the Client notes any deviation from
the facts about project characteristics, our office should be contacted immediately since this may
materially alter the recommendations. Further ALPHA TESTING, INC. is not responsible for
damages resulting from workmanship of designers or contractors and it is recommended the
Owner retain qualified personnel, such as a Geotechnical Engineering firm, to verify construction
is performed in accordance with plans and specifications.
r\
(4
~"\
APPENDIX
ALPHA Report No. 6451198 ~~~~
A-1 METHODS OF FIELD EXPLORATION
Using standard rotary drilling .equipment, a total of four (4) test borings have been performed
for this geotechnical exploration at the approximate locations shown on the Boring Location
Plan, Figure 1. The test boring locations have been staked by either pacing or taping and
estimating right angles from landmarks which could be identified in the field and as shown on
the site plan provided during this study. The Iocation of test borings shown on the Boring
Location Plan is considered accurate only to the degree implied by the method used to locate the
borings.
Relatively undisturbed samples of the cohesive subsurface materials have been obtained by
hydraulically pressing 3-inch O.D. thin-wall sampling tubes into the underlying soils at selected
depths (ASTM D 1587). These samples have bear removed from the sampling tubes in the field
and examined visually. One representative portion of each sample has been sealed in a plastic
bag for use in future visual examinations and possible testing in the laboratory.
Modified Texas Cone Penetration (TCP) tests have also been completed in the field to
determine the apparent in-place strength characteristics of the rock type materials. A 3-inch
diameter steel cone driven by a 170-pound hammer dropped 24 inches is the basis for Texas
State Department of Highways and Public Transportation strength correlations. In this
case, ALPHA TESTING, INC. has modified the procedure allowing the use of a 140~ouad
hammer dropping 30-inches for completion of the field test. Depending on the resistance
(strength) of the materials, either the number of blows of the hammer required to provide
12 inches of penetratian, ar the inches of penetration of the cone due to 100 blows of the hammer
are recorded on the field logs and are shown on the Reeord of Subsurface Exploration sheets as
TCP (reference: Texas State Department of Highways and Public Transportation, Bridge Design
Manual), using the modified procedure.
Logs of all borings have been included in the Appendix of this report. The logs show visual
descriptions of all subsurface strata encountered using the Unified Soil Classification System.
Sampling information, pertinent field data, and field observations are also included. Samples not
consumed by testing will be retained in our laboratory for at least 30 days and then discarded
unless the Client requests otherwise.
ALPHA Report No. GOS 1 I98
B-1 1VIETHODS OF LABORATORY TESTING
Representative samples are examined and classified by a qualified member of the Geotechnical
Division and the boring logs aze edited as necessary. To aid in classifying the subsurface
materials and to determine the general engineering characteristics, natural moisture content
tests (ASTM D 2216), Atterberg-limit tests {ASTM D 43 i 8) -and dry unit weight determinations
are performed on selected samples. In addition, unconfined compression (ASTM D 2166) and
_ pocket-penetrometer tests are conducted on selected soil samples to evaluate the soil shear
strength. Results of all laboratory tests described above aze provided on the accompanying
Record of Subsurface Exploralion sheets.
In addition to the Atterberg-limit tests, the expansive properties of the clay layer are further
_ analyzed by absorption swell tests. The swell test is performed by placing a selected sample in
the consolidation machine and applying either the approximate current or expected overburden
' pressure and then allowing the sample to absorb water. When the sample exhibits very little
tendency for further expansion, the height incxease is recorded and the percent free swell and
total moisture gain calculated. Results of the absorption swell test are provided on the Swell Test
' Data sheet, Figure 2 included in this appendix.
ABSORPTION SWELL TEST
Boring No. 2 3 4
Average Depth, ft 3 3 3
Dry Unit Weight, pcf 113 117 102
Liquid Limit 36 39 36
Plastic Limit 17 18 18
Plasticity Index 19 21 18
Initial Moisture Content, % 14 10 7
Final Moisture Content, % 20 16 21
Percent Free Swelt 5.6 0 0
Halff Associates, Inc.
Dallas, Texas
~~-
Coppell Town Cegter Plaza
Copped, Texas
5wed Test Data
Figure 2
GA51198 1 1/20/OG
ALPHA TESTING, INC. RECORD OF
2209 VYisconsin St, Suite 100
~~-~, Dallas, Texas 75229 SUBSURFACE EXPLORATION
(972) 620$911
Client HALFF & ASSOCIATES INC. Boring No. B-1 (2-PAGES) 70' HIGH TOWER
Archited/Engineer Job No. G051198
Project Name COPPELL TOFTL•I CENTER PLAZA Drawn By HC
Project Location COPPELL, TEXAS Approved BY HAR
nRn I ING ANn SAMPLING INFORMATION
TEST DATA
Date Started 1-OQ-06 Hammer Wt 140 Ibs_
Date Completed 1-OQ-06 Hartuner Drop 30 in.
Drill Foreman EDI Spoon Sample OD ~• o L
1 nspedor Rods ('.one Dia. in- O o
Boring Method CFA Shelby Tube OD 3 in. u, °o m a in
N r- a
O ~
~
O
F
C
°
O ~
a
°
a
o
~ -
a° -~
°
U 0
Q
~
c
E n v
SOIL CLASSIFICATION ~
- o -
m o ~ ~
~
~
W
J a
nq/. oa
o a
V a ~
°
~ as
~ ~ ~~
a0 ~
~ C
o
U ~~
~ ~ „
w
SURFACE ELEVATION ~ r=- ~ ~ ~- .
~- w c
~, a ~ ~_ ~~
~ a rp
~ ~ c j
~ ~ a
m J ¢_
°-
r n q
H W W U Q~ Q} O O «O O C O O O
2 ~~
~ n
~ J-J-
J d 4
N ~ ~ V) y Z rn F-- d I-- (n !n ~ F- {- .
Tan and Brown SANDY CLAY xith
5+
4
gravel and aalaareous nodules - 1 ST .
FILL.
2 ST d_5+ 13 LL=47
PL=19
PI=28
5 3 ST 4.5+ 9
4 ST 3.2 12
8'
Brown SANDY CLAY with silt
5
ST
2.2
15
LL=28
PL=15
10 PI=13
-gravel seams below 13'.
6 ST 0.5 13
15
18'
Gray CLAY SHALE.
7
1
7 ST .
20
21'
Gray SHALE.
8 TCP 100
25 2.8"
SAMPLER TYPE GROUNDWATER OBSERVATIONS BORING MET71vu
SS -STANDARD PENETRATION TEST AT COMPLETION 15 FT. NSA -HOLLOW STEM AUGERS
ST -SHELBY TUBE CFA -CONTINUOUS FLIGHT AUGERS
rn _ ~+ nrntirc AFTER HRS- FT- DG -DRIVEN CASINGS
ALPHA TESTING, INC. RECORD OF
2209 V1/iscOnsin St, Suite 100
/~~' (972) 62091175229 SUBSURFACE EXP LO RATI O N
Client HAI.FF 6 ASSOCIATES, ZNC. Boring No. B-1 (2-PAGES) 70' HIGH TOWER
ArchftecUEngineer Job No. G051198
Project Name COPPELL TOFiTT CENTER PLAZA Drawn By HC
-- ---
Project Location - - C'OI?r 4~IJ~_ TE~CAS Approved By HAR
DRILLING ANO SAMPLING INFORMATION
TEST DATA
uate Started 1- V Q -U b rtarrtnter wt. tau fvs.
Date Completed 1-04-06 Hanxner Drop 30 in.
Drill Foreman EDZ Spoon Sample 00 in. ~ L
Inspector Rods Core Oia. in.
~ w
o ~
o
t3oring Metfiod CFA Shetby Tube OD 3 in. r° ° m a ~;
o
o
cv ~ a
~
~ f
.-;
~ o
~
a
t'
O _
~
O O
~ ~
o X
a
Z
o o
c°
a ~ a
° n
E E
o o
SOiL CLASSIFICATION
h
~ f
- v ~ ~ J J
~ a p
ca o pti oiL ~ ~ -° a«
a o o ~ .,
SURFACE ELEVATION ~ ~ ~ ~ a a u, q~ pro a'~ ~ ~ Y ~ ~ o a =' p a
~W WU QO Q} ~
+
o o ° 0 80 00 ~'~' ~ M u
tno om fnz rnF- a f-tn ~n ter- aH an ~ ~aa
Gray SHALE. 9 TCp 100
30 2"
10 TCP 100
35 1.5"
11 TCP 100
40 1.2"
12 TCp 100
45 1"
13 TCP 100
50 0.8"
BOTTOM OF TEST BORING AT 50'.
55
SAMPLER TYPE
SS -STANDARD PENETRATION TEST
S7 -SHELBY TUBE
CA -CUTTINGS
T!'~~ TCYAC /"nNC DCIJCTOATI(1!J TGCT
GROUNDWATER OBSERVATIONS
AT COMPLETION 15 FT
AFTER HRS. FT
BORING METHOD
HSA -HOLLOW STEM AUGERS
CFA -CONTINUOUS FLIGHT AUGERS
DC -DRIVEN CASINGS
~~n _~su fn nR^ I INC;
ALPHA TESTING, INC.
2209 Wisconsin 5t., Suite 100 RECORD OF
/~'' 972) 620-891175 SUBSURFACE EXPLORATION
Client HALFF ~ ASSOCIATES , INC. Boring No. B-2 AMPHITIiEATER
Architect/Engineer Job No. G051198
Project Name COPPELL TtiG7N CENTER PLAZA Drawn By HC
Project Location COPPELL, TEXAS Approved By AAR
DRILLING AND SAMPLING INFORMATION TEST DATA
Date Started 12-19-05 Fianuix~r W'L 140
Date Completed 12-19-05 Ftarruner Drop 30 in .
Drill Foreman EDI Spoon Sample 00 in . '
'
Inspector Rode Core Dia in . _
Boring Method _
CFA Shelfiy Tube OD 3
in o
_ o o
a m
N F, n
a
r ° F a
o >4 0 ° w o
Z c° ~ t a a ._ v°
SOIL CLASSIFICATION a° ~ F° o Q t '~ E E I
~ O O ~ J ~`
a C d O O lL OIL ~ C ~ w V
SURFACE ELEVATION ~ ~ ~ ~ " ~ ~ ~ r ~ a Q ~ c " ~-° °
~W WU tL ~a °< rn c~« ~°c« iii `o ~4-d
~~ ?}. ~ raw 8~0 ~o ~a ~ ~ ~ ~
h~ ~~ rQnz ran F- a° I°vl v°> >cn1-- a-- ~~ p ~aa
Brown and Tan SANDY CLAY with
gyhavel and calcareous nodules. 1 ST 4.5+ 10
2 ST 4.5+ 113 ld LL=36
PL-=17
PI=19
5 3 ST 4.5+ 12
Dark Brown and Gray SILTY CLAY.~7,~ ~ 4 ~ ST 1 ~ ~ I f 1.7 ~ I15
10 -~---{ ST I I I I 1 2.2 I ~ 17 I Pi'18
-tannish brown with gravel and
calcareous nodules below 13'. 6 ST 0.5 15
15
_ _ _ _ _ 19 '
7 ST 4.5+
Gray CLAY SHALE ~ ~ 20•
Gray SHALE. ~ - ~ - 20
BOTTOM OF TEST BORING AT 25' . I I 25 ~ TCPI IO 3"
SAMPLER TYPE GROUNDWATER OBSERVATIONS BORING METHOD
SS -STANDARD PENETRATION TEST HSA -HOLLOW STEM AUGERS
AT COMPLETION 14 FT.
ST -SHELBY TUBE CFA - CONT1N110US FUGHT AUGERS
CA -CONTINUOUS FI..IGHT AUGER AFTER HRS. FI". DC -DRIVEN CASINGS
2A2osws~s sN surtNCoo RECORD OF
/~~ 972)620-891175229 SUBSURFACE EXPLORATION
Client HALFF ~ ASSOCIATES, INC. Boring No_ B-3 PODID AREA
Archftect/Engineer Job No. G051198
Project Name COPPELL TOWN CENTER PLASH Drawn By HC
Project Location COPPELL, TEXAS Approved By HAR
DRI LLING AND SAMPLING INFORMATION TEST DATA
Oate Started 12-19-05 Harrxner WL 140 Ibs.
Date Completed 12-19-05 Hammer Drop 30 in.
Drill Foreman EDI Spoon Sample 00 in. ~
Inspector
Rock Core Dia.
in.
a ~
a i
Boring Method CFA Shelby Tube OD 3 in. ~
r° c m a ~ I
~
N ~ N
C O
oF- _
~
O b
>
„
C
p
o _
V
O ~ O H O
O K
a
~~
a
E
E
o ~
SOIL CLASSIFICATION `„ a ~ ~ ~
p a ~
~ E j
J ~'
Q. U '
° C W
SURFACE ELEVATION ~
'QQ- t=-.
K d ~ ~
d Q J
a-
~ j
a w
~ a
~ E
,«, ~
x ~
rn' ~~
o b
p c - O
Y n
u c --
om` ~ U
o Q
A n a
^ w
~- W W U Q U Q~ V O q O C p~ O O Z' a ~
~
~a
rno ov> viz m a f-~n v> >F-- a-- o~ a
Broxn and Tan CLAY xith sand
and gravel -FILL. 1 ST 4.5+
2 ST 4.5+ 117 10 LL=39 '.
PL=18
PI=21
5 3 ST 4.5+ 8
6'
Dark Broxn SANDY CLAY. - -
4 ST 3.5 9 LL=34
PL=17
PZ=17
5 ST 2.5 15
10
i
-with gravel below 13'_ ~
6 ST 0.5 16
15
17'
Gray CLAY SHALE.
19'
- - - - - -
Gray SHALE 7 TCP 100
. 20 0.8"
BOTTOM OF TEST BORING AT 25'. ~ ~ 25 ~ TCPI IO 20'
SAMPLER Tl(PE
SS - STANDARD PENETRATION TEST
ST -SHELBY TUBE
GA -CUTTINGS
TCP- TEXAS C',ONE PENETRATION TEST
GROUNDWATER OBSERVATIONS
AT COMPLETION 7 FT.
AFTER HRS. FT.
u~nrco n~~ onnc i ~ cr
BORING METHOD
HSA -HOLLOW STEM AUGERS
CFA -CONTINUOUS FLIGHT AUGER°
DC -DRIVEN CASINGS
MD -MUD Dft1LL1NG
ALPHA TESTING, INC. RECORD OF
2209 Wisconsin St., Suite 100
~~~' 75229
6 SUBSURFACE EXP LO RATIO N
20-8911
(972)
gient HALFF & ASSOCIATES , INC. Boring No. B-4 POND OVERLOOK
Architect/Enginee r ,lob No. G051198
Project Name COPPELL TOWN CENTER PLAZA Drawn By HC
project Location COPPELL, TEXAS Approved By HAR
GRILLING ANO SAMPLING INFORMATION TEST DATA
Date Started 1-04-06 Hammer WL Ib
Gate Completed 1-OQ-06 Hammier Drop in.
Drill Foreman EDI Spoori Sample 00 im. ,~
Imspector Rode Core Dia. in- ~ i;
Boring Method CFA Shelby Tube OD 3 in. s
~ m -
a
J
SOIL CLASSIFICATION
SURFACE ELEVATION
Tan SANDY CLAY with gravel and
calcareous nodules.
-possible fill.
Dark Brown SANDY CLAY.
-tan and gray below 12'
Gray CLAY SHALE
BOTTOM OF TEST BORING AT 20'.
F- ., o
° b ~+
° o F- w ~
N ~ ° ~ O
Z ~ O t-.. n X
p C~ a ~ ~ e ~- C
a a c F~ U ~ a c E
p r J ~.
~ M cLL p $ li OU.. ~ C VT..~
W w °- °E ~ ctQ av rC ° ~a°
U G .. U v- o
r- 4J ~ n- W C r' C H C C w Y~ 7~ O N~ d
~~ W U ~~ Q?- ~ O O C~ O ~ O Z' a '0 JJ N
rno om wz 4S F- a F-v~ a> >Fiir- ai-- o~ ~ Jaa
1 ST 4.5+
2 ST 4.5+ 102 7 LL=36
PL=18
PI=18
5 3 ST 4.5+ 11
6'
4 ST 1.5 41 LL=39
PL=19
PI=20
5 ST 0.7 20
10
6 ST 1.5 18 LL=31
15 PI 16
18'
7 I ST
3.2
20
25
SAMPLER TYPE
SS -STANDARD PENETRATION TEST
ST -SHELBY TUBE
CA -CONTINUOUS FLIGHT AUGER
Ti+rf T'CVAO !~/11.1C OC~ICT°AT1M1 TCCT
GROUNDWATER OBSERVATIONS
AT COMPLETION 8 FT.
AFTER HRS. FT.
BORING METHOD
HSA -HOLLOW STEM AUGERS
CFA -CONTINUOUS FLIGHT AUGERS
DC -DRIVEN CASINGS
Mn -rug m nRa i w~
KEY TO SOIL SYMBOLS AND CLASSIFICATIONS
THE ABBREVIATIONS COMMONLY EMPLOYED ON EACH'"RECORD OF SUBSURFACE EXPLORATION',
. ON THE FIGURES ANO IN THE TEXT OF THE REPORT, ARE AS FOLLOWS:
I. SOIL DESCRIPTION
(A) COHESIONL.ESS SOILS
RELATIVE DENSITY
VERY LOOSE
LOOSE
MEDIUM
DENSE
VERY DENSE
(B) COHESIVE SOILS
CONSISTENCY
VERY SOFT
SOFT
FIRM
snFF
VERY STIFF
HARD
II. PLASTICITY
DEGREE OF
PLASTICITY
NONE TO LOW
LOW
MEDIUM
HIGH TO VERY HIGH
N, BLOWS/FT
0 TO 4
5 TO 10
11 TO 30
31 TO 50
OVER 50
Qu, TSF
LESS THAN 025
025 TO 0.50
0.50 TO 1.00
1.00 TO 2.00
2.00 TO 4.00
OVER 4.00
ISTICC
INDEX
0 TO 4
5 TO 15
16 TO 30
OVER 30
III. TYPICAL SOIL CLASSIFICATIONS
USCS SYMBOL DESCRIPTION
CH HIGH PLASTICRY CLAY
CL MEDIUM TO IOW PLASTICITY CLAY
SP POORLY GRADED SANG
SW WELL GRADED SANG
SM SILTY SAND
S C CLAYEY SAND
NOTE: ALL SOILS CIASSIFIEO ACCORDING TO THE UNIFIED SOIL
CIASSIFiCAT10N SYSTEM (USCS) (ASTM D-2487)
IV. RELATIVE PROPORTIONS
DESCRIf'T1VE TERM PERCENT
TRACE 1 TO 10
LITTLE 11 TO 20
SOME 21 TO 35
ANO 36 TO 50
V: PARTICLE SIZE IDENTIFICATION
8 INCH OWMETER OR MORE
COBBLES 3 TO 8 INCH DIAMETER
GRAVEL COARSE: 3/4 TO 3 INCH
FINE: 5.0 MM TO 3/41NCH
SAND COARSE: 2.0 MM TO 5.0 MM
MEDIUM: 0.4 MM TO 2.0 MM
FINE 0.07 MM TO 0.4 MM
SILT 0.002 MM TO 0.07 MM
CLAY 0.002 MM, OR LESS
VI. DRILLING AND SAMPLING SYMBOLS
CA CONTINUOUS AUGER SAMPLE
RC - ROCK CORE
TCP TEXAS CONE PENETRATION TEST
SS STANDARD PENETRATION TEST,
sPLar-SPOON: r o.o. ExcEPr
WHERE NOTEo
ST SHELBY TUBE: 3" O.D. EXCEPT
WHERE NOTED
WS WASHED SAMPLE
HSA HOLLOW STEM AUGERS
CFA CONTINUOUS FLIGHT AUGERS
MD MUD DRILLING
Qatxnn~car EhpiwNifg~CaKheA'on ,vaaras r«~-e~~cronrvrthy
'~""'°"°°"`~ ~ KEY TO SOIL SYMBOLS
/~,.
AND CLASSIFICATIONS
.ac~ta ~, rv~.
w
N
A
a
P~ ~
-~ ~ 'a
~ ~°
o .r 3 K
~F d u~
V H
Y,
°° v
° ~
o a.
w
~ ~ a '^
v
~ Cd „
a°.
0
V
' ~
.-r
.i
g w
-.. ~
n vii
U
O H
~~,,.
ALPHA TESflNG, INC.
2209 Wisconsin St., Suite 100
Dallas, Texas 75229
972/620-8911 - 972/263,4937 (Metro)
FAX: 972/620-1302
April 12, 2006
Ha1tY'Associates, Inc.
8616 Northwest Plaza Drive
Dallas, Texas 75225
Attention: Mr. Francois De Kock
Re: Pavement Recommendations
Coppell Town Center Plaza
Off Town Center near Parkway Boulevard
Coppell, Texas
ALPHA Report No. G051198-A
ALPHA previously completed a Geotechnical Exploration for the above referenced project as
ALPHA Report No. G051198 dated January 20, 2006. As requested by Iv1r. Francois De Kock,
paving recommendations for the proposed sidewalks/walkways are provided below. We
understand the sidewalks/walkways will be subject to occasional light vehicular traffic.
Sidewalks/Walkway Pavement
Sandy clay soils encountered at this site will probably constitute the subgrade for the planned
sidewalks/walkways. To permit correlation between information from the test borings and actual
subgrade conditions exposed during construction, a qualified Geotechnical Engineer should be
retained to provide subgrade monitoring and testing during construction. If there is any change
in project criteria, the recommendations contained in this report should be reviewed by our
office.
After final subgrade elevation along the sidewalks/walkways is achieved, the exposed surface of
the pavement subgrade soils should be scarified to a depth of at least 6 inches. Then, the
scarified soils should be compacted to at least 95 percent of standard Proctor maximum dry
density (ASTM D 698) and within the range of 1 percentage point below to 3 percentage points
above the material's optimum moisture content.
Pavement can then consist of at least 4.5 inches of adequately reinforced concrete. The above
pavement section will sustain wheel loads of light automobile vehicles. Portland-cement
concrete should have a minimum compressive strength of 3,000 lbs per sq inch (psi) at 28 days.
Concrete should be designed with 5 ± 1 percent entrained air. Joints in concrete paving should
not exceed I S ft. Reinforcing steel should consist of No. 3 bars placed at 24 inches on-center in
two directions.
ALPHA Report No. G051198-A
/i.
All other recommendations provided in the Geotechnical Exploration (ALPHA Report No.
GOS 1198 dated January 20, 2006) remain unchanged. ALPHA TESTING, INC. appreciates the
opportunity to be of service on this project. If we can be of further assistance, such as providing
materials testing services during construction, please contact our office.
Sincerely yours,
ALPHA TESTING, INC.
H a Addula
Project I~.ax3ager
HVABAP/har
Copies: (1) Client
..................:...
BRlANq, POK+~LL
GEOTECHNICAL ENGINEERING STUDY
COPPELL FIRE STATION #3 AND
POLICE STATION ADDITION
COPPELL,TEXAS
Presented To:
The City of Coppell
November 2005
PROJECT N0.687-05-01
~~„^,nM~ ENGINEERING, INC.
7636 Pebble Drive
Fort Worth, Tezas 76118
wvvw cmjengr.com
November 2, 2005
Report No. 687-05-01
City of Coppell
255 Parkway Boulevard
Goppefl, Texas 75019
Attn: Ms. Sheri Moino, Facilities Manager
GEOTECHNICAL ENGINEERING STUDY
COPPELL FIRE STATION #3 AND
POLICE STATION ADDITION
COPPELL, TEXAS
Dear Ms. Moino:
Submitted here are the results of a geotechnical engineering study for the referenced project.
This study was performed in general accordance with CMJ Proposal 05-1176 dated September
14, 2005. The geotechnical services were authorized by Mr. Jim Witt, City Manager of the City
of Coppell, on September 27, 2005.
Engineering analyses and recommendations are contained in the text section of the report.
Results of our field and laboratory services are included in the appendix of the report. We
would appreciate the opportunity to be considered for providing the materials engineering and
geotechnical observation services during the construction phase of this project.
We appreciate the opportunity to be of service to you and your consultants. Please contact us if
you have any questions or if we may be of further service at this time.
Respectfully submitted.,
CMJ ENGINEERING, I
li,~..f
~~•~'~,
James appington, IV, E.I.T.
Project anager
Texas o. ET-31361
~~
arrett E. Williams, P.E.
Senior Vice President
Texas No. 52525
copies submitted: (3) Ms. Sheri Moino; The City of Coppell
(1) Mr. Gary Beeman, AIA; Brinkley Sargent Architects
Phone (817) 284-9400 Fu (817) 589-9993 Metro (817) 589-9992
~~.2.05
1.0INTRODUCTION
1.1 Project Description
The project site is located at the existing Fire Station No. 3 at '133 E. Parkway Boulevard and the
existing Police Station at 130 Town Center Boulevard in Coppell, Texas. Proposed construction,
as currently planned, will consist of additions to the existing structures, each with building footprints
less than about 3,000 square feet. No new paving is planned for either structure. Plate A.1, Plan
of Borings, presents the approximate locations of the exploration borings.
1.2 Purpose and Scope
The purpose of this geotechnical engineering study has been to determine the general subsurface
conditions, evaluate the engineering characteristics of the subsurface materials encountered, and
develop recommendations for the type or types of foundations suitable for the project.
To accomplish its intended purposes, the study has been conducted in the following phases: (1)
drilling sample borings to determine the general subsurface conditions and to obtain samples for
testing; (2) performing laboratory tests on appropriate samples to determine pertinent engineering
properties of the subsurface materials; and (3) performing engineering analyses, using the field
and laboratory data to develop geotechnical recommendations for the proposed construction.
The design is currently in progress and the locations and/or elevations of the structure could
change. Once the final design is near completion (80-percent to 90-percent stage), it is
recommended that CMJ Engineering, Inc. be retained to review those portions of the construction
documents pertaining to the geotechnical recommendations, as a means to determine that our
recommendations have been interpreted as intended.
1.3 Report Format
The text of the report is contained in Sections 1 through 11. All plates and large tables are
contained in Appendix A. The alpha-numeric plate and table numbers identify the appendix in
which they appear. Small tables of less than one page in length may appear in the body of the text
and are numbered according to the section in which they occur.
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Units used in the report are based on the English system and may include tons per square foot
(tsf), kips (1 kip = 1,000 pounds), kips per square foot (ksf), pounds per square foot (psf), pounds
per cubic foot (pcf), and pounds per square inch (psi).
2.0 FIELD EXPLORATION AND LABORATORY TESTING
2.1 Field Exploration
Subsurface materials at the project site were explored by four (4) vertical soil borings. Borings B-1
and B-2 were drilled to 25 feet below existing grade in association with the addition at the existing
Fire Station. Borings 6-3 and B-4 also were drilled to depths of 25 feet for the addition at the
existing Police Station. The borings were drilled using continuous flight augers at the approximate
locations shown on the Plan of Borings, Plate A.1. The boring logs are included on Plates A.4
through A.7 and keys to classifications and symbols used on the logs are provided on Plates A.2
and A.3.
Undisturbed samples of cohesive soils were obtained with nominal 3-inch diameter thin-walled
(Shelby) tube samplers at the locations shown on the logs of borings. The Shelby tube sampler
consists of athin-walled steel tube with a sharp cutting edge connected to a head equipped with a
ball valve threaded for rod connection. The tube is pushed into the soil by the hydraulic pulldown
of the drilling rig. The soil specimens were extruded from the tube in the field, logged, tested for
consistency with a hand penetrometer, sealed, and packaged to limit loss of moisture.
The consistency of cohesive soil samples was evaluated in the field using a calibrated hand
penetrometer.. In this testa 0.25-inch diameter piston is pushed into the relatively undisturbed
sample at a constant rate to a depth of 0.25 inch. The results of these tests, in tsf, are tabulated at
respective sample depths on the logs. When the capacity of the penetrometer is exceeded, the
value is tabulated as 4.5+.
Disturbed samples of the noncohesive granular or stiff to hard cohesive materials were obtained
utilizing a nominal 2-inch O.D. split-barrel (split-spoon) sampler in conjunction with the Standard
Penetration Test (ASTM D 1586). This test employs a 140-pound hammer that drops a free fall
vertical distance of 30 inches, driving the split-spoon sampler into the material. The number of
blows required for 18 inches of penetration is recorded and the value for the last 12 inches, or the
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penetration obtained from 50 blows, is reported as the Standard Penetration Value (N) at the
appropriate depth on the logs of borings.
To evaluate the relative density and consistency of the harder formations, a modified version of the
Texas Cone Penetration test was performed at selected locations. Texas Department of
Transportation (TXDOT) Test Method Tex-132-E specifies driving a 3-inch diameter cone with a
170-pound hammer freely falling 24 inches. This results in 340 foot-pounds of energy for each
blow. This method was modified by utilizing a 140-pound hammer freely falling 30 inches. This
results in 350 foot-pounds of energy for each hammer blow. In relatively soft materials, the
penetrometer cone is driven 1 foot and the number of blows required for each 6-inch penetration is
tabulated at respected test depths, as blows per 6 inches on the log. In hard materials (rock or
rock-like), the penetrometer cone is driven with the resulting penetrations, in inches, recorded for
the first and second 50 blows, a total of 100 blows. The penetration for the total 100 blows is
recorded at the respective testing depths on the boring logs.
2.2 Laboratory Testing
Laboratory soil tests were performed on selected representative samples recovered from the
borings. In addition to the classification tests (liquid limits and plastic limits), moisture content, unit
weight, and unconfined compressive strength tests were performed. Results of the laboratory
classification tests, moisture content, unit weight, and unconfined compressive strength tests
conducted for this project are included on the boring logs.
Swell testing was performed on specimens from selected sample of the clays. These tests were
performed to help in evaluating the swell potential of soils in the area of the proposed additions.
The results of the swell test are presented on Plate A.8.
The above laboratory tests were performed in general accordance with applicable ASTM
procedures, or generally accepted practice.
3.OSUBSURFACE CONDITIONS
3.1 Site Geology
According to the Dallas Sheet of the Geologic Atlas of Texas, the project sites are geologically
located in the Alluvium and Fluviatile Terrace Deposits overlying the Eagle Ford Formation. The
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alluvial and terrace deposits are generally a mixture of fine-grained and coarse materials, which
are typically layered with grain sizes increasing with depth. At the surface the clay portions of
these deposits can be moderately to highly active. Ground-water is typically present in these
deposits, especially in the proximity of a river or creek.
3.2 Soil Conditions
Specific types and depths of subsurface strata encountered at the boring locations are shown on
the boring logs in Appendix A. The generalized subsurface stratigraphies encountered in the
borings are discussed below. Note that depths on the borings refer to the depth from the existing
grade or ground surface present at the time of the investigation, and the boundaries between the
various soil types are approximate.
Near surface soil consists of fill materials and extend to depths of 6.5 to 8 feet. Concrete was
present at the surface in Boring B-4 and is 7.25 inches in thickness. The fill materials consist of
dark brown, brown, gray, dark gray, and reddish brown clays, sandy clays, and silty clays of
moderate to high plasticity. Abundant calcareous nodules are present within the fill materials and
brick fragments were present from 2 to 3 feet in Boring B-3.
Natural soils consist of dark brown, gray, dark gray, reddish brown, and light reddish brown sandy
clays overlying brown, light brown, reddish brown, light reddish brown, and gray clays. Gravel and
ironstone gravel was present within the sandy clays typically below depths. of 12.5 to 15 feet. The
various clays encountered in the borings. had tested Liquid Limits (LL) ranging from 32 to 66 and
Plasticity, Indices (PI) ranging from 16 to 44 and are classified as CL and CH by the USCS. The
various clayey soils were generally firm to hard (soil basis) in consistency with pocket penetrometer
readings of 1.25 to over 4.5 tsf. Tested unit weight values ranged from 104 to 122 pcf and
unconfined compressive strengths were 2,620 to 4,160 psf.
Dark gray shale was encountered in Borings B-1 through B-4 at depths of 20 to 21 feet. The .dark
gray shale is hard to very hard (sedimentary rock basis) with Texas Cone Penetration (THD)
values of 0.5 to 2 inches per 100 blows.
The Atterberg Limits tests indicate the surficial clays encountered at this site are moderately active
to highly active with respect to moisture induced volume changes. Active clays can experience
volume changes (expansion or contraction) with fluctuations in their moisture content. The results
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of the swell test from Boring B-1 indicate a significant swell potential from present in-situ moisture
levels.
3.3 Ground-Water Observations
The borings were drilled using continuous flight augers in order to observe ground-water seepage
during drilling. Ground-water seepage was encountered during drilling in Borings B-3 and B-4 at
10.5 to 12.5 feet below existing grade. Ground-water was observed at completion of drilling
operations at 10 and 20 feet in Borings B-3 and B-4, respectively. Cave-in also was observed at
20 feet in Boring 6-4 at completion. Ground-water also was observed in these borings at the end
of the day at 15 feet in Boring B-3 and 9 feet in Boring B-4, with associated borehole cave-in at 18
to 20 feet. Borings B-1 and B-2 were dry during drilling and at the completion of drilling. Table 3.3-
1 summarizes the observed water level data. While it is not possible to accurately predict the
magnitude of subsurface water fluctuation that might occur based upon these short-term
observations, it should be recognized that ground-water conditions will vary with fluctuations in
rainfall. Seepage near the observed levels should be anticipated throughout the year.
TABLE 3.3-1
Ground-Water Observations
Boring Seepage During Water at Water at End of
No. Drilling (ft.) Completion (ft.) Day (ft.)
B-1 ' Dry Dry -
B-2 Dry Dry -
B-3 12.5 20 15
w/ cave-in at 20-
6-4 10.5 10 9
w/ cave-in at 20 w/ cave-in at 18
Fluctuations of the ground-water level can occur due to seasonal variations in the amount of
._ rainfall; site topography and runoff; hydraulic conductivity of soil strata; and other factors not
evident at the time the borings were performed.
Due to the variable subsurface conditions, long-term observations would be necessary to more
accurately evaluate the ground-water level. Such observations would require installation of
piezometer or observation wells which are sealed to prevent the influence of surface water.
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4.0 EXISTING FILLS
Existing fills were encountered to depths of 6.5 to 8 feet in the borings. Samples of the fills were
reasonably dense and free of significant voids. However, in the absence of documented density
control, the possibility of undercompacted zones or voids exists. Removal and replacement of all
the fill following the recommendations in subsequent sections of this report is the only method
eliminating the risk of unusual settlement.
Complete removal is discussed in the Floor Slabs section of this report. These methods are
intended to represent a reasonable approach for construction of slabs on-grade, however, they will
not eliminate the risk of unexpected movements in some areas.
5.0 FOUNDATION RECOMMENDATIONS
5.1 General Foundation Considerations
Two independent design criteria must be satisfied in the selection of the type of foundation to
support the proposed additions. First, the ultimate bearing capacity, reduced by a sufficient factor
of safety, must not be exceeded by the bearing pressure transferred to the foundation soils.
Second, due to consolidation or expansion of the underlying soils during the operating life of the
structure, total and differential vertical movements must be within tolerable limits. The
recommended foundation alternatives for the proposed additions are discussed below.
The moisture induced volume changes associated with the moderately active to highly active clays
present at this site and possible indeterminate settlement in the fills indicate that shallow or near
surface footings could be subject to differential movements of a potentially detrimental magnitude.
The most positive foundation .system for the proposed additions would be situated below the fills
and below the zone of most significant seasonal moisture variations. A deep foundation system
transferring column loads to a suitable bearing stratum is considered the most positive foundation
system. Straight drilled reinforced concrete shafts penetrating the gray shale is considered the
most positive foundation system and is recommended
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5.2 Straight Drilled Shafts
Recommendations and parameters for design of the piers are outlined below, while specific
recommendations for the construction and installation of the piers are included in the following
section.
Bearing Stratum Gray SHALE
Depth of Bearing Stratum: Approximately 20 to 21 feet below existing grades
Required Penetration: All piers should penetrate into the bearing stratum a
minimum of 2 feet.
Allowable End Bearing Capacity: 22,000 psf
Allowable Skin Friction: Applicable below temporary casing; 2,600 psf for
compressive loads and 1,700 psf for tensile loads.
Adjacent (both new and existing) shafts should have a minimum center-to-center spacing of 3
times the diameter of the larger shaft.
At the Police Station addition, it should be anticipated that ground-water seepage will be
encountered during installation of the straight shafts penetrating the gray shale and that seepage
rates and/or caving will be sufficient to require the use of temporary casing for installation of the
straight shafts. Seepage could also be encountered at the Fire Station addition. The casing
should be seated in the bearing stratum with all water and most loose material removed prior to
beginning the design penetration. Care must then be taken that a sufficient head of plasfic
concrete is maintained within the casing during extraction. Shaft excavations should be performed
with equipment suitable to perform this work by a contractor experienced in this area.
Settlement of properly constructed shafts should be primarily elastic and are estimated to be less
than 1.0 inch.
5.3 Soil Induced Uplift Loads
The drilled shafts could experience tensile loads as a result of post construction heave in the site
soils. The magnitude of these loads varies with the shaft diameter, soil parameters, and
particularly the in-situ moisture levels at the time of construction. In order to aid in the structural
design of the reinforcement, the reinforcement quantity should be adequate to resist tensile forces
based on soil adhesion equal to 1,500 psf acting over the upper 10 feet of the pier shaft. This load
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must be resisted by the dead load on the shaft, continuous vertical reinforcing steel in the shaft,
and a shaft adhesion developed within the bearing strata as previously discussed.
5,4 Drilled Shaft Construction Considerations
Care must be taken not to disturb the existing foundation system.
During construction one of the more important responsibilities of the pier excavation contractor and
the construction materials inspection laboratory will be to verify the presence of the bearing
materials encountered during construction, and that the pier excavation has not caved prior to
concrete placement.
Drilled pier construction should be monitored by a representative of the geotechnical engineer to
observe, among other things, the following items:
• Identification of bearing material
• Adequate penetration of the shaft excavation into the bearing layer
• The base and sides of the shaft excavation are clean of loose cuttings
• If seepage is encountered, whether it is of sufficient amount to require the use of temporary
steel casing. If casing is needed it is important that the field representative observe that a
high head of plastic concrete is maintained within the casing at all times during their
extraction to prevent the inflow of water
Precautions should be taken during the placement of reinforcing steel and concrete to prevent
loose,. excavated soil from falling into the- excavation. Concrete should be placed as soon as
practical after completion of the drilling, cleaning, and observation. Excavation for a drilled pier
should be filled with concrete before the end of the workday, or sooner if required to prevent
deterioration of the bearing material. Prolonged exposure or inundation of the bearing surface with
water will result in changes in strength and compressibility characteristics. If delays occur, the
drilled pier excavation should be deepened as necessary and cleaned, in order to provide a fresh
bearing surface.
The concrete should have a slump of 6 inches plus or minus 1 inch. The concrete should be
placed in a manner to prevent the concrete from striking the reinforcing cage or the sides of the
excavation. Concrete should be tremied to the bottom of the excavation to control the maximum
free fall of the plastic concrete to less than 10 feet.
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In addition to the above guidelines, the specifications from the Association of Drilled- Shaft
Contractors Inc. "Standards and Specifications for the Foundation Drilling Industry" as Revised
1999 or other recognized specifications for proper installation of drilled shaft foundation systems
should be followed.
5.5 Grade Beams
All grade beams should be supported by the drilled shafts. A minimum 8-inch void space should
be provided beneath all grade beams to prevent contact with the swelling clay soils. This void will
serve to minimize distress resulting from swell pressures generated by the clays.
Grade beams may be cast on cardboard carton forms or formed above grade. If cardboard carton
forms are used, care should be taken to not crush the carton forms, or allow the carton forms to
become wet prior to or during concrete placement operations. A soil retainer or trapezoidal void
forms should be provided to help prevent in-filling of this void.
Backfill against the exterior face of grade beams or panels should be properly compacted on-site
clays. Compaction should be a minimum of 93 percent of ASTM D 698; at a minimum of 2
percentage points above the optimum moisture content determined by that test. This clay fill is
intended to reduce surface water infiltration beneath'the structure.
6.0 FLOOR SLABS
6.1 Potential Vertical Movements
lightly loaded floor slabs placed on-grade will be subject to movement as a result of moisture
induced volume changes in the moderately active to highly active clays present at this site. The
clays expand (heave) with increases in moisture and contract (shrink) with decreases in moisture.
The movement typically occurs as post construction heave. The potential magnitude of the
moisture induced movements is rather indeterminate. It is influenced by the soil properties,
overburden pressures, and to a great extent by soil moisture levels at the time of construction. The
greatest potential for post-construction movement occurs when the soils are in a dry condition at
the time of construction. Based on the conditions encountered in the borings, potential moisture
induced movements for soils in a dry condition are estimated to be on the order of 4 inches at the
Fire Station and on the order of 2 to 2.5 inches at the Police Station.
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6.2 Structurally Suspended Floor Slab
The most positive method of preventing slab distress due to swelling soils is to structurally suspend
the interior slab. Support of the structural floor is provided by the drilled piers. Due to the
expansion potential of the site clays, it is recommended that the suspended floor slab be
constructed on carton forms with a minimum 12-inch void space.
Care should be taken to assure that the void boxes are not allowed to become wet or crushed prior to
or during concrete placement and finishing operations. Corrugated steel, placed on the top of the
carton forms, could be used to reduce the risk of crushing of the carton forms during concrete
placement and finishing operations. As a quality control measure during construction, "actual"
concrete quantities placed should be checked against "anticipated" quantities. Significant concrete
"overage" would be an early indication of a collapsed void.
Provision should be made to provide drainage of the crawl space below the slab, in the event water
becomes trapped or seeps into this area. Drain inlets which are tied into the storm sewer or a
sump and pump system may be necessary. Also, because of capillary moisture buildup, proper
ventilation should be provided in the crawl space below the slab. Ventilation of the void below the
floors should be provided if high humidity can cause problems with floor the adhesives.
Vehicle or pedestrian ramps leading up to the building should be structurally connected to the
building grade beams to avoid abrupt differential movement between the building slab and the
ramps. Transitioning details will be required at the points where ramps connect with paving and
slab on grade elements. In addition, ramp slabs should be constructed so that slopes sufficient for
effective drainage of surface water are still provided after potential differential movements.
6.3 Interior Floor Slabs
to conjunction with drilled shafts, interior slabs can be placed on a prepared subgrade. Slab-on-
grade construction should only be considered if stab movement can be tolerated. The level of
acceptable movement varies with the user, but methods are normally selected with the goal of
limiting slab movements to about one inch or less. Reductions in anticipated movements can be
achieved by using methods developed in this area to reduce on-grade slab movements. The more
commonly used methods consist of placing non-expansive select fill beneath the slab and moisture
conditioning the soils. The use of these methods will not eliminate the risk of unacceptable
movements.
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Readers should understand that aground-supported floor slab can heave considerably if placed on
dry, expansive clays.
Based on the conditions encountered at the Fire Station site, the installation of a minimum of 1 foot
of non-expansive select fill over a minimum of 8 feet of moisture conditioned clays should reduce
potential movements to on the order of one inch. Based on the conditions at the Police Station
site, the installation of a minimum of 1 foot of non-expansive select fll over a minimum of 5 feet of
moisture conditioned soils should reduce potential movements to on the order of one inch.
Mechanically reworking the clays, as discussed below, is the preferred method of moisture
conditioning. Reworking the clays will also serve to rework a portion of the existing fills. Slabs not
capable of tolerating movement should be structurally suspended.
Care must be taken not to disturb the existing foundation system and interior floor slab support of
the existing structures. Differential slab movements should be anticipated between the existing
slab and the addition unless the floor slab in both structures is structurally suspended. This office
should be contacted for additional recommendations relative to excavation adjacent to the existing
structures if these subgrade preparation measures are used. A structurally suspended floor
system may be more economically feasible for the additions as opposed to an interior slab-on-
grade due to construction issues relating to excavating adjacent to the existing structure.
Consideration should be given to extending the moisture conditioning process beyond the building
line to include entrances or other areas sensitive to movement. Outside the building, a single lift of
select fill (6 to 8 inches) is ~eeommended to minimize drying during construction.
Soil treatments presented in this section are referenced as an alternative to the use of a
structurally suspended floor slab. The owner must fully understand that if the floor slab is placed
on-grade, some movement and resultant cracking within the floor and interior wall partitions may
occur. This upward slab movement and cracking is usually difficult and costly to repair, and may
require continued maintenance expense.
It should be noted these methods of treatment are presented as an option for the owner's
consideration. The options may or may not be practical or economically feasible, depending on the
expected performance of the proposed structure. The owner should be aware that this method will
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not prevent movement of soil-supported foundation elements, and can only reduce the magnitude
of the movement. Placement. of the floor slab on-grade represents a compromise between
construction cost and risk of floor distress.
A properly engineered and constructed vapor barrier should be provided beneath slabs-on-grade
which will be carpeted or receive moisture sensitive coverings or adhesives.
6.3.1 Mechanical Reworking of Near-Surface Clays with 1' Select Fill Cap
In general, the procedure is performed as follows:
1. Remove all existing pavements, surface vegetation, trees and associated root mats, organic
topsoil and any other deleterious material.
2. Excavate sunlcial clays to a minimum of 8.5 feet below finished grade at the Fire Station and
4.5 feet below finished grade at the Police Station. As previously stated, care must be taken
not to disturb the existing foundation and subgrade beneath existing floor slabs. Scarify the
exposed clay subgrade to a depth of 8 inches, adjust the moisture, and compact at a minimum
of 3 percentage points above optimum moisture to between 93 and 98 percent of Standard
Proctor density (ASTM D 698). Over-compaction should not be allowed.
3. Fill pad to 1 foot below final grade using site excavated or similar clay soils. Compact in
maximum 9-inch loose lifts at a minimum of 3 percentage points above optimum moisture to
between 93 and 98 percent of Standard Proctor density (ASTM D 698). Over-compaction
should not be allowed.
4. Complete pad fill using a minimum of 1 foot of sandy claylclayey sand non-expansive select fill
with a Liquid Limit less than 35 percent and a Plasticity Index (PI) between 5 and 16. The
select fill should be compacted in maximum 9-inch loose lifts at minus 2 percent to plus 3
percentage points of the soil's optimum moisture content at a minimum of 95 percent of
Standard Proctor density (ASTM D 698). The select fill should be placed within 48 hours of
completing the installation of the moisture conditioned soils.
7.0 EXPANSIVE SOIL CONSIDERATIONS
7.1 Site Drainage
An important feature of the project is to provide positive drainage away from the proposed
buildings. If water is permitted to stand next to or below the structure, excessive soil movements
(heave) can occur. This could result in differential floor slab or foundation movement.
A well-designed site drainage plan is of utmost importance and surface drainage should be
provided during construction and maintained throughout the life of the structure. Consideration
should be given to the design and location of gutter downspouts, planting areas, or other features
which would produce moisture concentration adjacent to or. beneath the structure or paving.
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Consideration should be given to the use of self-contained, watertight planters. Joints next to the
structure should be sealed with a flexible joint sealer to prevent infiltration of surface water. Proper
maintenance should include periodic inspection for open joints and cracks and resealing as
necessary.
Rainwater collected by the gutter system should be transported by pipe to a storm drain or to a
paved area. 1f downspouts discharge next to the structure onto flatwork or paved areas, the area
should be watertight in order to eliminate infiltration next to the building.
7.2 Additional Design Considerations
The following information has been assimilated after examination of numerous projects constructed
in active soils throughout the area. It is presented here for your convenience. 1f these features are
incorporated in the overall design of the project, the performance of the structure should be
improved.
• Special consideration should be given to completion items outside the building area, such
as stairs, sidewalks, signs, etc. They should be adequately designed to sustain the
potential vertical movements mentioned in the report.
• Roof drainage should be collected by a system of gutters and downspouts and
transmitted away from the structure where the water can drain away without entering the
building subgrade.
• Sidewalks should not be structurally connected to the building. They should be sloped
away from the building so that water will drain away from the structure.
• The paving and the general ground surface should be sloped away from the building on
all sides so that water will always drain away from the structure. Water should not be
allowed to pond near the building after the stab has been placed.
• Every attempt should be made to limit the extreme wetting or drying of the subsurface
soils since swelling and shrinkage will result. Standard construction practices of providing
good surface water drainage should be used. A positive slope of the ground away from
the foundation should be provided to carry off the run-off water both during and after
construction.
• Backfill for utility lines or along the perimeter beams should consist of on-site material so
that they will be stable. If the backfill is too dense or too dry, swelling may form a mound
along the ditch line. If the backfill is too loose or too wet, settlement may form a sink along
the ditch line. Either case is undesirable since several inches of movement is passible
and floor cracks are likely to result.- The soils should be processed using the previously
discussed compaction criteria.
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8.OSEISMIC CONSIDERATIONS
Based on the conditions encountered in the borings for the above referenced project the IBG2000
site classification is TYPE C for seismic evaluation.
9.0 EARTHWORK
9.1 Site Preparation
The subgrade should be firm and able to support the construction equipment withouf displacement.
Soft or yielding subgrade should be corrected and made stable before construction proceeds. The
subgrade should be proof rolled to detect soft spots, which if exist, should be excavated to provide
a firm and otherwise suitable subgrade. Proof rolling should be performed using a heavy
pneumatic tired roller, loaded dump truck, or similar piece of equipment. The proof rolling
operations should be observed by the project geotechnical engineer or his/her representative.
9.2 Placement and Compaction
Fill material should be placed in loose lifts not exceeding 8 inches in uncompacted thickness. The
uncompacted lift thickness should be reduced to 4 inches for structure backfill zones requiring
hand-operated power compactors or small self-propelled compactors. The fill material should be
uniform with respect to material type and moisture content. Clods and chunks of material should
be broken down and the fill material mixed by disking, blading, or plowing, as necessary, so that a
material of uniform moisture and density is obtained for each lift. Water required for sprinkling to
bring the fill material to the proper moisture content should be applied evenly through each layer.
The on-site soils are suitable for use in site grading. Imported fill material should be clean soil with
a Liquid Limit less than 60 and no rock greater than 4 inches in maximum dimension. The fill
materials should. be free of vegetation and debris.
The fill material should be compacted to a density ranging from 95 to 100 percent of maximum dry
density as determined by ASTM D 698, Standard Proctor. In conjunction with the compacting
operation, the fill material should be brought to the proper moisture content. The moisture content
for general earth fill should range from 2 percentage points below optimum to 5 percentage points
above optimum (-2 to +5). These ranges of moisture contents are given as maximum
recommended ranges. For some soils and under some conditions, the contractor may have to
Report No. 687-05-01
cNtJ ~rcuv~uNC, uvc
14
maintain a more narrow range of moisture content (within the recommended range) in order to
consistently achieve the recommended density.
Field density tests should be taken as each lift of fill material is placed. As a guide, one field
density test per lift for each 5,000 square feet of compacted area is recommended. For small areas
or critical areas the frequency of testing may need to be increased to one test per 2,500 square
feet. A minimum of 2 tests per lift should be required. The earthwork operations should be
observed and tested on a continuing basis by an experienced geotechnician working in conjunction
with the project geotechnical engineer.
Each lift should be compacted, tested, and approved before another lift is added. The purpose of
the field density tests is to provide some indication that uniform and adequate compaction is being
obtained. The actual quality of the fill, as compacted, should be the responsibility of the contractor
and satisfactory results from the tests should not be considered as a guarantee of the quality of the
contractor's filling operations.
9.3 Trench Backfill
Trench backfill for pipelines or other utilities should be properly placed and compacted. Overly
dense or dry backfill can swell and create a mound along the completed trench line. Loose or wet
backfill can settle and form a depression along the completed trench line. Distress to overlying
structures, pavements, etc. is likely if heaving or settlement occurs. On-site soil fill material is
recommended for trench backfill. Care should be taken not to use free draining granular material,
to prevent the backfilled trench from becoming a french drain and piping surface or subsurface
water beneath structures, pipelines, or pavements. If a higher class bedding material is required
for the pipelines, a lean concrete bedding will limit water intrusion into the trench and will not
require compaction after placement. The soil backfill should be placed in approximately 4 to 6-
inch loose lifts. The density and moisture content should be as recommended for fill in Section 9.2,
Placement and Compaction, of this report. A minimum of one field density test should be taken per
lift for each 150 linear feet of trench, with a minimum of 2 tests per lift.
9.4 Excavation
The side slopes of excavations through the overburden soils should be made in such a manner to
provide for their stability during construction. Existing structures, pipelines or other facilities, which
Report No. 687-05-01
c~vtJ Errcnv~xu~rc, uvc.
15
are constructed prior to or during the currently proposed construction and which require
excavation, should be protected from loss of end bearing or lateral support.
Temporary construction slopes and/or permanent embankment slopes should be protected from
surface runoff water. Site grading should be designed to allow drainage at planned areas where
erosion protection is provided, instead of allowing surface water to flow down unprotected slopes.
Trench safety recommendations are beyond the scope of this report. The contractor must comply
with all applicable safety regulations concerning trench safety and excavations including, but not
limited to, OSHA regulations.
9.5 Acceptance of Imported Fill
Any soil imported from off-site sources should be tested for compliance with the recommendations
for the particular application and approved by the project geotechnical engineer prior to the
materials being used. The owner should also require the contractor to obtain a written, notarized
certification from the landowner of each proposed off-site soi} borrow source stating that to the best
of the landowner's knowledge and belief there has never been contamination of the borrow source
site with hazardous or toxic materials. The certification should be famished to the owner prior to
proceeding to furnish soils to the site. Soil materials derived from the excavation of underground
petroleum storage tanks should not be used as fill on this project.
9.6 Soil Corrosion Potential
Specific testing for soil corrosion potential was not included in the scope of this study. However,
based upon past experience on other projects in the vicinity, the soils at this site maybe corrosive.
Standard construction practices for protecting metal pipe and similar facilities in contact with these
soils should be used.
9.7 Erosion and Sediment Control
All disturbed areas should be protected from erosion and sedimentation during construction, and
all permanent slopes and other areas subject to erosion or sedimentation should be provided with
permanent erosion and sediment control facilities. All applicable ordinances and codes regarding
erosion and sediment control should be followed.
Report No. 687-05-01
c~tJ ~rvc~xuvc, uvc
16
10.0 CONSTRUCTION OBSERVATIONS
In any geotechnical investigation, the design recommendations are based on a limited amount of
information about the subsurface conditions. {n the analysis, the geotechnical engineer must
assume the subsurface conditions are similar to the conditions encountered in the borings.
However, quite often during construction anomalies in the subsurface conditions are revealed.
Therefore, it is recommended that CMJ Engineering, Inc. be retained to observe earthwork and
foundation installation and perform materials evaluation during the construction phase of the
project. This enables the geotechnical engineer to stay abreast of the project and to be readily
available to evaluate unanticipated conditions, to conduct additional tests if required and, when
necessary, to recommend alternative solutions to unanticipated conditions. Until these
construction phase services are performed by the project geotechnical engineer, the
recommendations contained in this report on such items as final foundation bearing elevations,
proper soil moisture condition, and other such subsurface related recommendations should be
considered as preliminary.
It is proposed that construction phase observation and materials testing commence by the project
geotechnical engineer at the outset of the project. Experience has shown that the most suitable
method for procuring these services is for the owner or the owner's design engineers to contract
directly with the project geotechnical engineer. This results in a clear, direct line of communication
between the owner and the owner's design engineers and the geotechnical engineer.
11.0 REPORT CLOSURE
The boring logs shown in this: report contain information related to the types of soil encountered at
specific locations and times and show lines delineating the interface between these materials. The
logs also contain our field representative's interpretation of conditions that are believed to exist in
those depth intervals between the actual samples taken. Therefore, these boring logs contain both
factual and interpretive information. Laboratory soil classification tests were also performed on
samples from selected depths in the borings. The results of these tests, along with visual-manual
procedures were used to generally classify each stratum. Therefore, it should be understood that
the classification data on the logs of borings represent visual estimates of c{assifications for those
portions of each stratum on which the full range of laboratory soil classification tests were not
performed. It is not implied that these logs are representative of subsurface conditions at other
locations and times.
Report No. 687-05-01 CMJ ENGINEERING, ING
17
Wth regard to ground-water conditions, this report presents data on ground-water levels as they
were observed during the course of the field work. In particular, water level readings have been
made in the borings at the times and under conditions stated in the text of the report and on the
boring logs. It should be noted that fluctuations in the level of the ground-water table can occur
with passage of time due to variations in rainfall, temperature and other factors. Also, this report
does not include quantitative information on rates of flow of ground water into excavations, on
pumping capacities necessary to dewater the excavations, or on methods of dewatering
excavations. Unanticipated soil conditions at a construction site are commonly encountered and
cannot be fully predicted by mere soil samples, test borings or test pits. Such unexpected
conditions frequently require that additional expenditures be made by the owner to attain a properly
designed and constructed project. Therefore, provision for some contingency fund is
recommended to accommodate such potential extra cost.
The analyses, conclusions and recommendations contained in this report are based on site
conditions as they existed at the time of our field investigation and further on the assumption that
the exploratory borings are representative of the subsurface conditions throughout the site; that is,
the subsurface conditions everywhere are not significantly different from those disclosed by the
borings at the time they were completed. If, during construction, different subsurface conditions
from those encountered in our borings are observed, or appear to be present in excavations, we
must be advised promptly so that we can review these conditions and reconsider our
recommendations where necessary. If there is a substantial lapse of time between submission of
this report and the start of-the work at the site, if conditions have changed due either to natural
causes or to construction operations at or adjacent to the site, or if structure locations, structural
loads or finish grades are changed, we urge that we be promptly informed and retained to review
our report to determine the applicability of the conclusions and recommendations, considering the
changed. conditions and/or time lapse.
Further, it is urged that CMJ Engineering, Inc. be retained to review those portions of the plans and
specifications for this particular project that pertain to earthwork and foundations as a means to
determine whether the plans and specifications are consistent with the recommendations
contained in this report. In addition, we are available to observe construction, particularly the
compaction of structural fill, or backfill and the construction of foundations as recommended in the
report, and such other field observations as might be necessary.
Report No. 687-05-01 CMJ ENGINEERING, INC
18
The scope of our services did not include any environmental assessment or investigation for the
presence or absence of wetlands or hazardous or toxic materials in the soil, surface water, ground
water or air, on or below or around the site.
This report has been prepared for use in developing an overall design concept. Paragraphs,
statements, test results, boring logs, diagrams, etc. should not be taken out of context, nor utilized
without a knowledge and awareness of their intent within the overall concept of this report. The
reproduction of this report, or any part thereof, supplied to persons other than the owner, should
indicate that this study was made for design purposes only and that verification of the subsurface
conditions for purposes of determining difficulty of excavation, trafficability, etc. are responsibilities
of the contractor.
This report has been prepared for the exclusive use of The City of Coppell and their consultants for
specific application to design of this project. The only warranty made by us in connection with the
services provided is that we have used that degree of care and skill ordinarily exercised under
similar conditions by reputable members of our profession practicing in the same or similar locality.
No other warranty, expressed or implied, is made or intended. These recommendations should be
reviewed once a grading plan is finalized.
t .
Report No. 687-05-01
CMJ ENGINEERING, INC
19
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~1~1 JENGINEERING, iNC. COPPELL FIRE STATION #3 PLATE
AND POLICE STATION ADDITION ,L~, ~
CMJ PROJECT No. 687-05-01 COPPELL, TEXAS
Major Divisions Sym. Typical Names Laboratory Classification Criteria
H ~ Well-graded gravels, gravel- ~ o to z
~
m ~, c GW sand mixtures, little or no ~, c~= 60 greater than 4: C~ '
between 1 and 3
'~ o fines 'y C+o D1u x D~
c me a iLC~ H
m ~ y ~ m
~ w Poorly graded gravels, gravel •~
GP
°' ~ ~ ~
N ~-- a, c sand mixtures, little or no cn N y Not meeting all gradatio n requirements for GW
> ~~ fines y n.'~~
°
m >
m o .a ~ C9 a
o° ~ ° z° ° o
c Silty gravels, gravel-sand-si lt N ~ C? = Liquid and Plastic limits
"
"
Liquid and plastic limits
cv
d =
~,_, ~
t ~ L ro ~,
L .r GM
mixtures h
Z ~ ~
~ below
A
line or P.I.
greater than 4
Plotting in hatched zone
°' °' ~ N between 4 and 7 are
N~
'o w w H~ `F-
~' > ~ ° N p
'N N ~
~
Liquid and Plastic limits
borderline cases
N ~ o ~ a Cla a ravels, ravel-sand
GC y y g g -
c o m above "A" line with P
I requiring use of dual
,
~v rn
~ ~ ~ ~ Q
~- day mixtures
~ ~
; ~ .
.
greater than 7 y
s mbols
y ~ r
O) ~
y ~ ~
m H c
SW Well-graded sands, gravelly O ~-
~ ~ O
' m
D~
to,~~
o ~ E ~ v- sands, little or no fines ~ N ~~ o„ 9neater than 6: Cc D x D between ~ and 3
U ~ h N C ~ c
O 10 60
~
w C ~-
° N a~~i a°i
Poorly graded sands; 'p r
cca ;~
.~ U v SP gravelly sands, little or no c m ~ ~ Not meeting all gradation requirements for SW
t y N m fines °~ m o..s
~
L C ~ M
l4 ~ `cr O O O
N m aN ~
1t~ ~
.
-~
o ~ o z° ~ ~ Silty sands
sand-silt ~ ~° c °1
s Liquid and Plastic limits
~ ~ ~ ~ ~ ,
SM mixtures ~ ~ 3 .
~, ~, ~ below A line or P.I. less Liquid and plastic limits
,t w ~ ~ y ` a o ~ ° ° than 4 plotting between 4 and 7
cco ~ ~ c a o y '-' ~ ~ are borderline cases
m ~ 'v ~
`
~'
Clayey sands
sand-clay ~ ~' a
~ Liquid and Plastic limits requiring use of dual
o
f°
~ ~ Q ,
SC
mixtures ~ ~?
m ~ 'N above "A" line with P.I. symbols
Q a, m ~ greater than 7
v O O U
Inorganic silts and very fine
o ML sands, rock flour, silty or
u~ clayey fine sands, or clayey
~ = silts with slight plasticity
m ~ ~ Inorganic days of low to
y = ~ medium plastidty, gravelly
CL
o y '~ days, sandy days, silty days,
~`'
o = =
~ ~ and lean days
Z ~
Q
s -'
`'' Organic silts and organic silty
OL
N ` days of low plastidty x
•y ~
f~ c
N -. Inorganic silts, micaceous or
~~ `~ '~ MH diatomaceous fine sandy or
c ~ c silty soils, elastic sifts a
it ~ y .
r~6 ~
U ~
° ~ `
' CH Inorganic days of high
L ° °
y plasticity, fat days
~
L in =
~_
F
4 CH
.P OH a d MH
2
CL
~ ML a d OL
4
0
>n Q Organic days of medium to
g° v OH high plastidty, organic silts o ~0 20 so ao so so ~0 8o so goo
Liquid Limit
~ U
O 'N Pt Peat and other highly organic Plasticity Chart
soils
UNIFIED SOIL CLASSIFICATION SYSTEM PLATE A.2
SOIL OR ROCK TYPES
ma
m ~ GRAVEL LEAN CLAY LIMESTONE
.• ••
• • SAND . •
• • • SANDY - SHALE
• • ••
SILT SILTY s. SANDSTONE
CLAYEY HIGHLY CONGLOMERATE Shelby Auger
PLASTIC CLAY Tube Split
Spoon Rodc
Core Cone
Pen No
Recovery
TERMS DESCRIBING CONSISTENCY, CONDITION, AND STRUCTURE OF SOIL
Fine Grained Soils (More than 50°~ Passing No. 20o sieve>
Descriptive Item Penetrometer Reading, (tsf)
Soft 0.0 to 1.0
Firm 1.0 to 1.5
Stiff 1.5 to 3.0
Very Stiff 3.0 to 4.5
Hard 4.5+
COarSe Grained SOIIS (More than 50°~ Retained on No. 200 Sleve)
Penetration Resistance Oescttiptive Item Relative bensity
(blows/foot)
0 to 4 Very Loose 0 to 20%
4 to 10 Loose 20 to 40%
10 to 30 Medium Dense 40 to 70%
30 to 50 Dense 70 to 90%
Over 50 Very Dense 90 to 100%
Soil Structure
Calcareous Contains appreciable deposits of calcium carbonate; generally nodular
Slickensided Having inclined planes of weakness that are slick and glossy in appearance
Laminated Composed of thin. layers of varying color or texture
Fissured Containing cracks, sometimes filled with fine sand or silt
Interbedded Composed of alternate layers of different soil types, usually in approximately equal proportions
TERMS DESCRIBING PHYSICAL PROPERTIES OF ROCK
Hardness and Degree of Cementation
Very Soft or Plastic Can be remolded in hand; corresponds in consistency up to very stiff in soils
Soft Can be scratched with fingemail
Moderately Hard Can be scratched easily with knife; cannot be scratched with fingemail
Hard Difficult to scratch with knife
Very Hard Cannot be scratched with knife
Poorly Cemented or Friable Easily crumbled
Cemented Bound together by chemically precipitated material; Quartz, calcite, dolomite, siderite,
and iron oxide are common cementfig materials. and iron oxide are common cementing materials.
Degree of Weathering
Unweathered Rock in its natural state before being exposed to atmospheric agents
Slightly Weathered Noted predominantly by color change with no disintegrated zones
Weathered Complete color change with zones of slightly decomposed rock
ExtremT y Weathered Complete color change with consistency, texture, and general appearance approaching soil
KEY TO CLASSIFICATION AND SYMBOLS PLATE A.3
!'~71.! T
Project No.
687-OS-Ol Boring No. Project Coppell Police and Fire Station Vl~'1J '"""""""~"""""'
B-1 Co ell, Texas
Location Water Observations
See Plate A.1 Dry during drilling; dry at completion
Completiaa Completion
Depth 25.0' Date 10-8-OS
Surface Elevation Type
N/A Ri : B-53, w/ 6" CFA
Ls.
a
A p u
~ -'
~~
~ ~
tratum Description
o
~`3a
~
a
u:
L ~Q
o a
~ ~
o~~
maE~ ~
°
o
~o
~.~
am
~
~~
:a :a
~
~~
a:-1
~
~~
a~
~
~ c
oo
~U
w
a a
a~;
a..a
a w
~',•y c
~ ~ ~
~o~
~Ua;
CLAY. SILTY CLAY, AND SANDY CLAY, dark 4.5+
brown and brown, w/ calcareous nodules, very stiff to 4.5+
hard ~~~ 4.5+ 66 22 44 19 104
4.5+
3.25
5
25
3
iff .
SANDY CLAY, dark brown, fum to st
2.5
1
12
l
5'
17'
/
.
grave
,
to
-grades gray and reddish brown, w
1.25 32 13 19 16 118 2620
15
CLAY, brown and gray, w/shale seams, hard
100/1.5"
2 - - SHALE. dark gray, hard to very hard
- 100/0.5"
25 -- -----------------------
LOG OF BORING NO. B-1 _ PLATE A.4
!`I l ! T
Project No.
687-OS-Ol _ - _ _. _ l_.1V1J c,wuvncna,w uv~. -
Boring No. Project Coppell Police and Fire Station
$-2 Co ell, Texas
Location Water Observations
See Plate A.1 Dry during drilling; dry at completion
Completion Completion
em'u' 25.0' Date 10-8-OS
Surface Elevation Type
N/A Ri : B-53, w/ 6" CFA
F`'
p,
A ~ .=
~ ~
Stratum Description
o
W~
r~
e
a
t>~
oa
~ ~
o ~ ~
CGaH S
o
m~
~~ ~
a.v~
~ ~
.~"~
.a .a
~ o
~~ '~
a..l
.~
~ ~
a~
e
~ ~
.o o
~U
A ~
[ ~
~«.1 -
vcw
~ ~ ~
~ o
~Ua
CLAY AND SANDY CLAY dark brown, brown, 4.5+
gray, and reddish brown, w/ calcareous nodules, very 4.5+
stiff to hard (fill) 4.5+
3.5 15
4.5+
5
SANDY CLAY
d
k b
tiff t
e
tiff
ar
rown, s
o v
ry s
, 4.0
2.25 52 17 35 21
1
-grades gray and reddish brown, w/gravel, 13' to 16'
3.0 20 111 2670
15
CLAY, light brown and reddish brown, hard
00/0.75
2
- - SHALE, dark gray, hard to very hard
~ 100/1"
25
z
s
i
i
i -----------------------
.
LOG OF BORING NO. B-2 PLATE A.5
CMJ FNGIIJEERING wC
Project No. Boring No.
.
Project Coppell Police and Fire Station
687-OS-Ol $-3 Co ell, Tezas
Location Water Observations
See Plate A.1 Seepage at 12.5' during drilling; water at 20' at completion; water at 15'
Completion Completion and cave-in at 20' at end of day
D~ilr 25.0' Date 10-8-OS
Surface Elevation Type
N/A Ri : B-53, w/ 6" CFA
w
rte..-
a ~ ~
~
T
N
~~
o g o
~°,
°
0
w
a w
a~i .q r;,.
~'
A N Stratum Description ~ a ~ ~ mo o ~_ ~ ~ ~ a ~ w ~
a4 n: GO a. FH a. v~ :..~ ;.7 w .a a .° ~ U a ..a ~ U w
CLAY AND SILTY CLAY dark brown and dark 3.0
gray, stiffto very stiff (fill)
'
' 4.5+
-hard, 1
to 2 2
75
-w/brick fra
ments
2' to 3' .
g
, 2.75
-w/ calcareous nodules, 4' to 5' 2.0 31
5
2.75
SANDY CLAY, dark brown, w/calcareous nodules,
very stiff 3.5 34 13 21 16 109
1
12
d li
h
ddi
h b
fi
tiff
5'
d
.
-gra
es gray an
g
t re
rown,
rm to s
,
s
to 18'
1.5 38 15 122 3070
15 -w/ abundant ironstone gravel, 15' to 18'
CLAY, brown, light brown, and gray, w/shale seams,
very stiff 4.0
- - SHALE, dark gray, hard
- 00/1.75'
2S -----------------------
~_
~_
o ,
U
a'
z
0
m
LL
o
J
LOG OF BORING NO. B-3 PLATE A.6
/'ll ! T
Project No.
687-OS-Ol Bonin No. Pro'ed _ ~'1V1J u.~u,~~~ "~~~ -
S ~ Coppell Police and Fire Station
B-4 Co ell, Tezas
Location Water Observations
See Plate A.1 Seepage at 10.5' during drilling; water at 10' and cave-in at 20' at
Completion Completion completion; water at 9' and cave-in at 18' at end of day
Dail' 25.0' Date 10-8-OS
Surface Elevation Type
N/A Ili : I3-53, w/ 6" CFA
~,
'~ ~
a.
A N °~
~
~ Stratum Description
o
W~W
cx
~
o.
u:
o c
w ~
o~~
Gga.fF o
o
m~
~.~
a.v~
~
a~
:a ::a
_
~~
a~
~
~~
a.~
0
~ -
'oo
~U
3w
~~
•Ep
~.a
~•y d'
~ N~
~a~
~Ua
` '"~ CONCRETE 7.25 inches thick 3.0
CLAY AND STi,TY CLAY dark browq w/ 3.5
calcareous nodules, stiff (fill) 3.0 50 18 32 21
4.25
.1.5
5
3.25
SANDY CLAY, dark gay, w/ calcareous nodules,
stiff 2.75 17 116 4160
1
l
12
/i
5'
,
.
to
-gades light reddish brown, w
ronstone gave
18'
34
15
CLAY, light reddish brown and gray, hard
100/2"
2 - - SHALE, dark gran hard
100/1.5"
25 -----------------------
LOG OF BORING NO. B-4 PLATE A.7
FREE SWELL TEST RESULTS
Project: Coppell Police and Fire Station
Coppell, Texas
Project No.: 687-05-01
Free swell tests performed at approximate overburden pressure
CMJ ENGINEERING, INC. PLATE A.8