6283C - Construction of Denton Regional Public Safety Training Facility, Addendum 1GEOTECHNICAL ENGINEERING
SERVICES REPORT
For the proposed
PUBLIC TRAINING FACILITY
4111 VINTAGE BOULEVARD
DENTON, TEXAS
Prepared for
Mr. Herman Lawson
City of Denton – Facilities Management
869 S Woodrow Lane
Denton, Texas 76205
Prepared by
Professional Service Industries, Inc.
310 Regal Row, Suite 500
Dallas, Texas 75247
Telephone (214) 330-9211
PSI Project No. 03421219
September 2, 2016
TABLE OF CONTENTS
Page No.
1.0 PROJECT INFORMATION ............................................................................... 1
1.1 Project Authorization ............................................................................................ 1
1.2 Project Description ............................................................................................... 1
1.3 Purpose and Scope of Services ........................................................................... 1
2.0 SITE AND SUBSURFACE CONDITIONS ........................................................ 3
2.1 Site Location and Description ............................................................................... 3
2.2 Field Exploration .................................................................................................. 3
2.3 Laboratory Testing ............................................................................................... 4
2.4 Site Geology ......................................................................................................... 4
2.5 Subsurface Conditions ......................................................................................... 4
2.6 Groundwater Information...................................................................................... 5
3.0 EVALUATION AND RECOMMENDATIONS ................................................... 6
3.1 Soil Shrink-Swell Potential ................................................................................... 6
3.2 Geotechnical Discussion ...................................................................................... 6
3.3 Site Preparation and Fill Materials ....................................................................... 7
3.4 Straight Shaft Drilled Pier Recommendations ...................................................... 8
3.5 Drilled and Underreamed Piers Foundation Recommendations. ....................... 11
3.6 Shallow Foundations Recommendations ........................................................... 12
3.7 Floor Slab Recommendations ............................................................................ 13
3.8 Seismic Design .................................................................................................. 15
4.0 PAVEMENT RECOMMENDATIONS ............................................................. 16
4.1 Subgrade Soil Preparation ................................................................................. 16
4.2 Pavement Section .............................................................................................. 16
5.0 CONSTRUCTION CONSIDERATIONS.......................................................... 18
5.1 Secondary Design Considerations ..................................................................... 18
5.2 Construction Materials Testing ........................................................................... 19
5.3 Moisture Sensitive Soils/Weather Related Concerns ......................................... 19
5.4 Drainage and Groundwater Concerns................................................................ 19
5.5 Excavations ........................................................................................................ 19
6.0 REPORT LIMITATIONS ................................................................................. 21
APPENDIX A
Site Vicinity Map
Aerial Plan with Boring Location
Boring Location Plan
Boring Logs
Key to Terms and Symbols Used on Logs
APPENDIX B
PSI Project No. 0342-85019
PSI Project No. 0342-85019 Addendum I
DENTON PUBLIC TRAINING FACILITY PSI REPORT NO. 03421219
4111 VINTAGE BOULEVARD, DENTON, TEXAS SEPTEMBER 2, 2016
PROFESSIONAL SERVICE INDUSTRIES, INC. PAGE 1 OF 21
1.0 PROJECT INFORMATION
1.1 Project Authorization
Professional Service Industries, Inc. (PSI) has completed the geotechnical exploration for the
proposed Public Training Facility to be located at the northeast corner of 4111 Vintage Boulevard in
Denton, Texas. This geotechnical engineering study was authorized by Mr. Herman with The City of
Denton on July 18, 2016 by signing the Proposal Acceptance. The scope of the study was
performed in general accordance with PSI Proposal No. 184505-R dated July 18, 2016.
1.2 Project Description
Project information was provided to PSI by Mr. Brett Atchison with PGAL. The information provided
included the project site plan, location, and brief description of the project.
Based on the information provided, the proposed development consists of:
A burn tower;
Flash chamber;
Outdoor classroom;
Propane tank area;
Future Roof Building; and
Parking and drive areas
Based on the planned improvements, this proposal is based on the assumed structural loading as
follows:
Column Load: 360 kips or less
Wall Load: Less than 3 kips per linear foot
Floor Slab: Less than 150 psf
PSI previously performed a geotechnical exploration for the proposed development and provided
recommendations in PSI report No. 0342-85019, dated April 11, 2008 and PSI report No. 0342-
85019 Addendum I dated June 24, 2008. It is understood that the project was put on hold since then.
Based on Google Earth information, the site is covered with grass and scattered trees. It is
anticipated that boring locations are accessible to the truck mounted drill rig. The report is based on
the assumption that finished grades within the building area will be within 4 feet of the existing grades.
The geotechnical recommendations presented in this report are based on the available project
information, site location, laboratory testing, and the subsurface materials described in this report.
If any of the noted information is incorrect, please inform PSI in writing so that we may amend the
recommendations presented in this report if appropriate and if desired by the client. PSI will not
be responsible for the implementation of its recommendations when it is not notified of changes
in the project.
1.3 Purpose and Scope of Services
The purpose of this study was to explore the subsurface conditions at the site and to provide
geotechnical evaluation and recommendations for the proposed construction. The scope of work for
this project included drilling five borings extending to a depth of approximately 25 and 60 feet
below the existing grade. The scope also included performing laboratory testing and preparing
DENTON PUBLIC TRAINING FACILITY PSI REPORT NO. 03421219
4111 VINTAGE BOULEVARD, DENTON, TEXAS SEPTEMBER 2, 2016
PROFESSIONAL SERVICE INDUSTRIES, INC. PAGE 2 OF 21
this geotechnical report containing geotechnical recommendations as well as a review of previous
reports and incorporating the previous analysis into the current study.
This report briefly outlines the testing procedures, presents available project information,
describes the site and subsurface conditions, and presents recommendations regarding the
following:
Site preparation recommendations;
Estimated potential soil movements associated with moisture induced volume changes;
Foundation types, depths, allowable bearing capacities, and an estimate of potential
movement;
General pavement section design criteria and pavement subgrade preparation;
Definition of the seismic site class using the International Building Code (IBC) 2012
edition; and
Comments regarding factors that may impact construction and performance of the
proposed construction.
The scope of services did not include an environmental assessment for determining the presence or
absence of wetlands, or hazardous or toxic materials in the soil, bedrock, surface water,
groundwater, or air on or below, or around this site. Any statements in this report or on the boring
logs regarding odors, colors, and unusual or suspicious items or conditions are strictly for
informational purposes. A geologic fault study to evaluate the possibility of surface faulting at this site
was beyond the scope of this investigation. Should you desire a detailed fault study, please contact
us.
DENTON PUBLIC TRAINING FACILITY PSI REPORT NO. 03421219
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2.0 SITE AND SUBSURFACE CONDITIONS
2.1 Site Location and Description
The project site is located at 4111 Vintage Boulevard in Denton, Texas. Based on the available aerial
photos and the provided survey, the project site is generally flat and the ground cover is grass with
scattered trees. Based on the site layout, it appears that within the plan area of the proposed
development anticipated cuts and fills will be less than 4 feet to achieve the finished grade. The truck
mounted drill rig experienced no difficulties in moving around the site during the field exploration.
2.2 Field Exploration
Subsurface conditions at the site were explored by drilling ten borings at the approximate locations
shown on the Aerial Plan with Boring Locations included in the Appendix A. The borings were located
using available landmarks and hand-held GPS and were drilled to the depths given in Table 2.1
below.
TABLE 2.1: BORING LOCATIONS AND DEPTHS
Boring Number Boring Location Depth Drilled
B-101 Administration Building
Area* 25 feet
B-102 Residential Burn Building
Area* 25 feet
B-103 Burn Tower Area 25 feet
B-201 Burn Tower Area 55 feet
B-202 Outdoor Classroom Area 55 feet
Note: * denotes a building referenced that has since been removed from the
scope of the project.
The boring location plan also shows the locations of borings B-01 through B-11 performed in 2008
during the previous study.
Elevations of the ground surface at the boring locations were not provided to PSI and should be
determined by others prior to construction. Therefore, the references to depth of the various materials
encountered are from the existing grade at the time of drilling (August, 2016).
The borings were drilled and sampled in general accordance with ASTM standards. Drilling
equipment utilized for this project included truck-mounted rotary drilling equipment with appropriate
support vehicles. Field activities were accomplished in accordance with PSI’s safety manual. The
borings were drilled using continuous flight auger drilling techniques.
The borings were sampled continuously to a depth of ten-feet and at five-foot intervals thereafter.
Soil formations were sampled using a three-inch O.D. seamless steel tube sampler (ASTM D
1587) and a two-inch O.D. split barrel sampler (ASTM D 1586). A hand penetrometer was used
as an aid in evaluating the relative shear strength of the soils encountered during drilling. The
hand penetrometer readings are shown on the boring logs at the corresponding sample depths.
In addition, rock formations were tested at five-foot intervals using Texas Cone Penetrometer in
general accordance with TEX-132 E.
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Groundwater level measurements were recorded at boring locations during the field operations
and were noted on the boring logs. The borings were backfilled with soil cuttings after the drilling
operations were completed.
The subsurface conditions during drilling were monitored, logged and visually classified in the
field by a geotechnical technician. Field notes were maintained for soil types and description,
water levels, changes in subsurface conditions, and drilling conditions. After completion of field
activities, the samples were transported to the laboratory in general accordance with ASTM D
4220. The soil samples were sealed in plastic bags and placed in secured containers prior to
being transported to the geotechnical laboratory.
Boring logs, which include soil descriptions, water level information, laboratory test data,
stratifications, classifications based on the ASTM D 2487 and D2488, and sample types and
depths are included in the Appendix. A key to descriptive terms and symbols used on the boring
logs is also presented in the Appendix.
2.3 Laboratory Testing
Laboratory testing of soils was performed in general accordance with applicable ASTM
procedures. The laboratory testing program was established so that the engineering design
parameters produced from the tests are appropriate for use in the engineering analyses and in
support of the conclusions and recommendations.
The geotechnical laboratory testing included the following tests:
1. Classification (ASTM D 2487 / 2488)
2. Moisture Content (ASTM D 2216)
3. Atterberg Limits (ASTM D 4318)
4. Percent Soil Particles Finer than No. 200 Sieve (ASTM D1140)
5. Unconfined Compression Test (ASTM D 2166)
The samples not tested in the laboratory will be stored for a period of 60 days subsequent to
submittal of this report and will be discarded after this period, unless other arrangements are
made prior to the disposal period.
2.4 Site Geology
As shown on the Sherman Sheet of the Geologic Atlas of Texas published by the Bureau of
Economic Geology of the University of Texas at Austin, the site is located in an area where
Quaternary Age terraced alluvial deposits are located at the surface. The terraced alluvial
deposits generally consist of clays, silts, sands, and gravels deposited within the floodplain of the
river areas and their tributaries
2.5 Subsurface Conditions
The subsurface conditions identified at the boring locations are shown on the boring logs included
in the Appendix section of this report. A key to terms and symbols used on the logs is also included
in the Appendix. Based on the subsurface conditions identified by the exploratory borings,
generalized subsurface profiles at this site is shown in Table 2.2.
DENTON PUBLIC TRAINING FACILITY PSI REPORT NO. 03421219
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PROFESSIONAL SERVICE INDUSTRIES, INC. PAGE 5 OF 21
TABLE 2.2 GENERALIZED SUBSURFACE PROFILE
Stratum Depth Range
(feet) Description
I 0 to 4.5 Fat Clay (CH), stiff to hard, dark brown
II 2 to 33 Lean Clay (CL), very stiff to hard, brown and light brown,
with calcareous deposits
III 30 to 50 Shale, soft to hard, gray
IV 50 to 55 Limestone, hard to very hard, gray
2.6 Groundwater Information
The initial water levels were measured in the open boreholes during drilling and attempts were
made to measure final water levels. At boring location B-103, groundwater was encountered
during drilling at a depth of 22 feet and at the completion of drilling activities at a depth of 22 feet.
At boring location B-202 groundwater was encountered during drilling at a depth of 30.5 feet and
at the completion of drilling activities at a depth of 29.5 feet. The remaining borings appeared dry
at completion.
Groundwater levels fluctuate seasonally as a function of rainfall, proximity to creeks, rivers and lakes,
the infiltration rate of the soil, seasonal and climatic variations and land usage. Water seepage will
largely depend on the permeability of the soils. If more detailed water level information is required,
observation wells or piezometers could be installed at the site, and water levels could be monitored.
The groundwater levels presented in this report are the levels that were measured at the time of
our field activities. It is recommended that the contractor determine the actual groundwater levels
at the site at the time of the construction activities to determine the impact, if any, on the
construction procedures.
DENTON PUBLIC TRAINING FACILITY PSI REPORT NO. 03421219
4111 VINTAGE BOULEVARD, DENTON, TEXAS SEPTEMBER 2, 2016
PROFESSIONAL SERVICE INDUSTRIES, INC. PAGE 6 OF 21
3.0 EVALUATION AND RECOMMENDATIONS
3.1 Soil Shrink-Swell Potential
The resu lts of laboratory plasticity tests indicate that moderate to high plasticity clay soils are
present at this site. The soils have a tendency to swell when soil moisture increases and shrink
when the soil moisture decreases. The amount of potential soil movement due to shrinking and
swelling with soil moisture variations is represented or indicated by Potential Vertical Rise (PVR). In
designing the soil-supported structures, the structural/civil engineer should take movements
associated with shrinking-swelling soils into account.
PVR estimates are based on an assumed depth known as “Active Depth” to which the soil moisture
variations could occur due to seasonal variations. It is noted that the active depth assumed herein
may not represent the moisture variations that can occur at greater depths due to the presence of
large tree root systems that could desiccate the soils, the presence of other heating units, or soil
wetting due to pipe leaks, poor drainage, etc. It is very difficult to predict the moisture variations
under the structure during its service life. The PVR estimates provided herein should be
considered approximate probable estimates based on industry standard practice and experience,
and the movements predicted herein should not be construed as absolute values that could occur
in the field.
Using the Texas Department of Transportation (TXDOT) TEX-124-E method, the estimated PVR
value is on the order of 1 to 2½ inches.
Poor drainage and water infiltration into the foundation soils can be detrimental to the ground
supported structures. Excessive wetting of soil (due to accumulation of water), or, excessive drying
(due to the presence large trees, etc) could possibly result in greater PVR values than those
estimated herein. It is recommended that the moisture-related problems be corrected immediately.
It is important to help reduce the possibility of moisture changes by following the precautions
shown below:
1. Direct surface runoff away from structures by sloping the subgrade away from the slabs.
2. Extend paving or other impervious coverings, such as sidewalks, to the slab edge.
3. Extend roof drain downspouts so that the discharge is at least 5 feet from the slab.
4. Avoid placing trees or shrubs adjacent to slab.
5. Avoid excessive drying of soil around the slab.
3.2 Geotechnical Discussion
Based on the project information as well as field and laboratory results, the proposed
developments will be supported by straight shaft pier foundation system. Both grade supported
and structurally suspended floor slab systems can be considered for the building.
For any ground supported structures, it will be necessary to perform modifications to the subgrade
in order to reduce the movement associated with shrinking and swelling soils. Detailed
geotechnical recommendations are presented below.
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3.3 Site Preparation and Fill Materials
The following site preparations apply to the proposed building areas. It is recommended that
existing vegetation be removed from the proposed construction area. The removal depth of
organics could be 6 inches. A PSI representative should witness the earthwork activities.
After stripping of deleterious materials and excavating to the desired grade, the exposed soil
should be proof-rolled to locate any soft or loose areas. Proof-rolling shall be performed in
accordance with Item 216 of Texas Department of Transportation (TxDOT), Standard
specification for construction of highways, streets and bridges (TxDOT Spec) or equivalent
procedure. Soils that are observed to rut or deflect excessively under the moving load should be
undercut and replaced with properly compacted fill materials. A PSI representative should witness
the proof-rolling and undercutting activities. It is advisable to perform the earth-work activities
during a period of dry weather. The proof rolled subgrade shall be scarified to a depth of 6-inches
and compacted as shown in Table 3.1. After the completion of proof-rolling and undercutting
activities, necessary fill placement may commence.
Fill materials should be free of organics, miscellaneous debris and of particles greater than 3
inches. If water must be added, it should be uniformly applied and thoroughly mixed into the soil
by disking or scarifying. Care should be taken to apply compaction throughout the fill areas. The
moisture content and degree of compaction of the fill should be maintained until the construction
of structures. Each lift of fill should be tested by a representative of the geotechnical engineer
prior to placement of subsequent lifts. Lift thicknesses and compaction requirements are shown
in Table 3.1 Compaction Specifications.
Common Fill: Common fill should be cohesive soils with a plasticity index of less than 30.
Common fill may consist of on-site/imported materials and may be used in structural and non-
structural areas of the site. The first layer of common fill material should be placed in a relatively
uniform horizontal lift and be adequately keyed into the prepared subgrade soils. Common fill
should be placed and compacted to the specifications as shown in Table 3.1.
Select Fill: Select fill materials shall be sandy lean clay or lean clay (CL) soils that have a liquid
limit not greater than 35 and a plasticity index between 8 and 18. Select fill should be placed and
compacted to the specifications as mentioned in Table 3.1.
Moisture Conditioned Clay Fill: Moisture conditioned fill is on-site or imported cohesive soil
that is pre-swelled by mechanically mixing water during the compaction process which is also
referred as Moisture Treated Subgrade (MTS). The first layer of moisture conditioned fill should
be placed in a relatively uniform horizontal lift and be adequately keyed into the prepared
subgrade soils. Moisture Conditioned Fill shall have a clay lump size of less than 2-inches.
Moisture Conditioned Fill should be placed and compacted to the specifications as shown in as
shown in Table 3.1.
Lime Treated Soils: The lime treated soils are soils that are treated with 6 to 8% of lime
expressed as percent of the dry weight of the soil to be treated. In order to determine the
percentage of lime addition, lime series testing should be performed in accordance with ASTM
D6276 or TxDOT test method TEX-112-E (pH-Series). In addition, the soils should be checked
for sulfates (TEX-145-E) prior to the use of lime. Lime treatment should be performed in
accordance with the applicable provisions of Item 260 of the TxDOT Specification. Lime Treated
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soils can be used as Select Fill materials. Lime treated soil should be placed and compacted to
the specifications as shown in Table 3.1.
TABLE 3.1: COMPACTION SPECIFICATIONS
FILL TYPE LOOSE LIFT
THICKNESS
MINIMUM PERCENT
OF MAXIMUM DRY
DENSITY (MDD)
RANGE OF
COMPACTION
MOISTURE FROM
OPTIMUM MOISTURE
CONTENT (OMC)
PROCTOR
TEST
METHOD
Common Fill or
Moisture Treated
Soils
8 inches 95 or greater +2% or greater ASTM D 698
Select Fill 8 inches 95 or greater 0% to +4% ASTM D 698
Lime Treated Soils 8 inches 95 or greater 0% to +4% ASTM D 698
3.4 Straight Shaft Drilled Pier Recommendations
The column and wall loads for the proposed structure may be supported on drilled straight shafts.
The axial load carrying capacity of a drilled shaft can be computed using the static method of
analysis. According to this method, axial capacity, Q, at a given penetration is taken as the sum
of the skin friction on the side of the shaft, Qs, and the end or point bearing at the shaft tip, Qp, so
that:
Q = Qs + Qp = fAs + qAp
where As and Ap represent, respectively, the embedded surface area and the end area of the
shaft; f and q represent, respectively, the unit skin friction and the unit end or point bearing.
The total allowable axial capacity in compression will be the summation of the allowable frictional
capacity and the allowable end bearing capacity. The total allowable axial capacity in tension will
be the allowable frictional capacity alone neglecting end bearing component.
3.4.1 Axial Capacity: For this site, based on the evaluation of the subsurface conditions, field
and laboratory test results, it is recommended that straight drilled shafts bear in the shale or
limestone. The drilled shafts should extend at least 3 feet or 2-diameters into shale/rock.
Allowable unit skin friction and allowable end bearing values are shown in Table 3.2. Skin friction
in the overburden soils should be neglected. A factor of safety of at least 2.0 is included for both
the unit skin friction and end bearing to arrive at the allowable values.
Based on the final grade at the foundation locations, the length of the shaft and the penetration into
the bearing stratum should be determined using the recommended allowable side friction and end
bearing values. After the design is finalized, PSI should be given the opportunity to check the final
length, embedment depth and bearing elevation.
Table 3.2. Recommended Allowable Unit Skin Friction and End Bearing Values
STRATUM TOP OF ROCK DEPTH (FEET) SKIN FRICTION (TSF) END BEARING (TSF)
Gray Shale Encountered between 30 and
35 feet 1.25 12
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3.4.2 Expansive Soil Considerations: Drilled shafts extending through potentially expansive
soils are subjected to vertical uplift loads should the soils become moist or wet and swell against
the shaft. For this reason, each drilled shaft should be designed with sufficient steel reinforcement
to resist the tensile stresses caused by the expansive soil uplift.
Drilled shafts placed within swelling soils and should be checked for an expansive soil uplift load of
38d kips; where d is the diameter of the shaft in feet. The reinforcement in the shaft should be
checked for this uplift load alone neglecting any dead loads on the shaft. The uplift load is calculated
based on 1,000 pounds per square foot of uplift friction due to swelling soils along the shaft surface
area to a depth of 12 feet. The drilled shaft should be extended to a minimum of 3 feet into the gray
limestone layer to provide resistance to the swelling uplift load alone. This penetration is calculated
using a factor of safety of 1.3 for friction resistance in the limestone.
Wall loads and Grade Beams: Wall loads should be transmitted to the drilled shafts by grade beams
and the grade beam should be structurally connected to the shafts. Void boxes can be provided
under the grade beams to avoid movements associated with shrinking and swelling soils. A minimum
of 6-inch void space is recommended beneath the grade beams.
These voids can be produced using compressible cardboard carton forms manufactured
specifically for this purpose. Care should be exercised so that the forms are not crushed, damaged
or allowed to become saturated prior to placement of the concrete. In addition, barriers that will
not rapidly decay should be placed or constructed along the sides of the cardboard carton forms
to prevent soil intrusion into the void after the carton forms decay. Galvanized steel or aluminum
sheet metals are two examples of materials that can be used for this purpose.
3.4.3 Settlement: An isolated drilled shaft having a diameter of less than 60 inches designed as
discussed, the foundation settlement should be about ½ inch. A detailed group settlement
analysis was not performed, as the actual group configurations are unknown at this time.
However, for a shaft group bearing in limestone, large settlements are not anticipated. If a group
settlement analysis is desired, PSI should be contacted to perform such a settlement analysis.
3.4.4 Lateral Capacity: For drilled shafts, the soils as well as the rigidity of the shaft will resists
the lateral loads applied to the shaft. After the location, loads, and other pertinent information are
provided, PSI can assist in performing lateral load analyses based on methods ranging from chart
solutions to the ‘p-y’ approach utilizing computer programs such as LPILE or COM 624. The lateral
loads on the shaft can also be designed based on the criteria provided in the FHWA-Drilled Shaft
Manual.
The lateral design information regarding the ‘p-y’ data is provided in Table 3.3. This relationship
between the soil resistance (p) and pile deflection (y) is commonly referred to as ‘p-y’. Along the
depth of the shaft, soil resistance (p) is expressed as a non-linear function of lateral shaft
deflection (y). Various researchers developed ‘p-y’ criteria for different types of soils. The ‘p-y’
curves can be automatically generated using the computer program LPILE. The program LPILE
was developed by Lymon Reese and Shin-Tower Wang, Ensoft, Inc.
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TABLE 3.3: SOIL PARAMETERS TO BE USED IN THE LATERAL LOAD ANALYSES
SOIL TYPE ‘P-Y’ CRITERIA
EFFECTIVE
UNIT WEIGHT,
(PCF)
SU OR QU
KS (PCI) OR
KC(PCI) OR
E (PSI)
50 OR KRM RQD
In-Situ
Clays
Stiff Clay w/o
Free Water
Criteria
125 Su: 1,250 psf Ks = 500
Kc = 200 50 = 0.007 --
Moisture
Conditioned
Clays
Soft Clay 125 Su: 750 psf -- 50 = 0.010 --
Gray Shale Weak Rock
Criteria 75 Qu = 150 psi Er = 30,000 krm = 0.0005 70
Note: Su-Undrained Shear Strength (psf); Qu-Unconfined Compressive Strength (psi); Er- Initial Modulus
(psi); 50 – strain corresponding to one-half the principle stress; krm – a constant for overall stiffness. RQD-
Rock Quality Designation.
3.4.5 Group Action: A group of drilled shafts subjected to vertical or lateral loads may not
necessarily have the same capacity as the sum of the capacities of the individual shafts. For axially
or laterally loaded drilled shafts, published results indicate that the ratio of capacity per shaft in a
group to that of a single isolated shaft typically ranges from 0.5 to 1.0.
For axially loaded shafts, this efficiency factor depends on the spacing or distance between each
shaft. In planning groups of drilled shafts embedded in rock, a minimum center-to-center spacing of
2D (where D is the diameter or the width) is recommended to avoid the reduction in capacity.
For laterally loaded shafts, the efficiency factor depends on the shaft spacing (distance between
each shaft) and on the direction of loading with respect to the orientation of the shaft group.
Research indicates a minimum spacing of 3 diameters to 6 diameters is required depending on
the direction of loading with respect to the orientation of the shafts in a group.
Group action should be checked after the actual shaft spacing is determined. Further, if the shaft
spacing is designed to be closer, construction sequence and other installation issues must be
addressed. PSI should be contacted, after the shaft group orientation, spacing and loading direction
is determined.
3.4.6 Groundwater and Construction: Groundwater was encountered during drilling operations
at B-103 at a depth of 22 feet and at B-202 at a depth of 29.5 feet. Therefore, drilled shaft
excavations are likely to experience groundwater infiltration. Temporary casing may be used
where necessary to stabilize pier holes and to reduce water inflow. If more than 4 inches of water
collects in the shaft excavation in less than one-half hour a temporary casing is recommended.
The successful completion of drilled pier excavations will depend, to a large extent, on the
suitability of the drilling equipment together with the skill of the operator. The sequence of
operations should be scheduled so that each pier can be drilled, reinforcing steel placed, and the
concrete poured in a continuous, rapid, and orderly manner to reduce the time that the excavation
is open.
Shafts should be clean and be free of all loose materials prior to placement of concrete. The
drilled shafts should be installed in accordance with Item 416 of TxDOT specifications, ACI 336.1
specifications, or FHWA-NHI-10-016 guidelines. We recommend a PSI representative be present
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to verify the bearing stratum, bearing depth, bearing soil condition, bearing area and that the pier
installation procedures meet the specifications.
3.5 Drilled and Underreamed Piers Foundation Recommendations.
It is recommended that the development foundations be supported on drilled and underreamed
piers. The piers should be placed at a depth of about 12 feet below the existing ground surface
bearing on stiff clay soils. Individual piers bearing in the clays can be designed for a maximum
allowable net bearing pressure of 6,000 psf for dead plus live loads and 4,000 psf for dead plus
sustained live loads, whichever results in the larger underream.
Piers extending through expansive soils are potentially subjected to vertical uplift loads should
the soils become moist and swell. For this reason, each pier should be designed with sufficient
steel reinforcement to resist the tensile stresses. Piers placed within natural swelling soils at this
site should be checked for reinforcement with a tension loads of 38d kips; where d is the diameter
of the piers in feet. The reinforcement of the pier should be checked for this tension load alone
neglecting any dead loads on the pier.
A single isolated pier with a bell diameter of about 8 feet or less and designed as discussed should
experience a settlement on the order of one-half inch or less. However, if a cluster of closely
spaced piers is planned, PSI should be contacted to calculate the estimated amount of settlement.
After the foundation sizes and configuration are finalized, PSI should be contacted in estimating
the amount of settlement.
Wall loads should be transmitted to the drilled piers by grade beams and the grade beam should
be structurally connected to the piers. Void boxes should be provided under the grade beams to
avoid movements associated with shrinking and swelling soils. A minimum 4-inch void space is
recommended beneath the grade beams and pier caps.
These voids can be produced using compressible cardboard carton forms manufactured
specifically for this purpose. Care should be exercised that that the forms are not crushed,
damaged, or allowed to become saturated prior to placement of the concrete. In addition, barriers
that will not rapidly decay should be placed or constructed along the sides of the cardboard carton
forms to prevent soil intrusion into the void after the carton forms decay. Galvanized steel or
aluminum sheet metals are two examples of materials that can be used for this purpose.
For the construction of the underream or bell, a bell diameter to pier diameter ratio of 2 to 1 is
recommended. We believe that a bell to pier diameter ratio of up to 3 to 1 can be achieved at this
site, if the bell angle to the horizontal is 60˚.
The uplift capacity of drilled and underreamed piers can be determined from the following semi-
empirical relationship:
Qu = Nu *Su **(D2 – d2)/4
Where: Qu = ultimate uplift capacity, tons
Nu = 3.5*(H/D) 9
Su = Undrained Shear Strength, tons per square feet
D = diameter of underream or bell, feet
d = diameter of shaft, feet
DENTON PUBLIC TRAINING FACILITY PSI REPORT NO. 03421219
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PROFESSIONAL SERVICE INDUSTRIES, INC. PAGE 12 OF 21
H = depth to base of bell below ground surface, feet
For bells excavated within the natural clay, the value of Undrained Shear Strength, “Su” in the
above equation can be taken as 0.75 tons per square foot. The ultimate value should be reduced
by a factor of safety of 2.0 for transient and wind loads and 3.0 for sustained loads.
The lateral loads on shallow drilled and underreamed piers can be resisted by passive resistance
of the soil. The allowable passive resistance of soil may be taken as 1,000 psf. The value includes
a factor of safety of 2.0. Determination of the lateral load carrying capacity using the passive earth
pressure does not predict the lateral pier-head load versus pier-head deflection behavior of the
drilled pier. It is recommended that the passive resistance from the upper two feet of soil be
neglected and the passive resistance from any uncompacted fill material be neglected.
The successful completion of drilled and underreamed excavations will depend, to a large extent,
on the suitability of the drilling and underreaming equipment together with the skill of the operator.
The sequence of operations should be scheduled so that each underream can be completed,
reinforcing steel placed and the concrete poured in a continuous, rapid and orderly manner to
reduce the time that the excavation is open.
Groundwater was not encountered during drilling operations. Therefore, drilled pier excavations
are not likely to experience groundwater infiltration. Due to the fluctuations of the groundwater
table with the season and amount of precipitation, the possibility of encountering groundwater
during field operations cannot be dismissed. Temporary casing may be used where necessary to
stabilize pier holes and to reduce water inflow. If more than 4 inches of water collects in the pier
excavation in less than one-half hour a temporary casing is recommended.
Underream excavations and the bearing area should be clear and free of loose materials prior to
placement of concrete. Placement of concrete in the excavations should commence immediately
after the underream excavation is complete. A PSI representative should verify that the
underream installation procedures meet specifications. Installation of the piers can be carried out
in accordance with ACI 336.1, Item 416 of TxDOT specifications, or the guidelines provided in the
Drilled Shaft Manual, Publication No. FHWA-IS-99-025.
3.6 Shallow Foundations Recommendations
The proposed building may be supported on shallow spread footings/grade beams or monolithic,
steel reinforced stiffened slab-on-grade foundation system (i.e., a waffle type grade beam
configuration), provided that some differential movement can be tolerated and provided the
recommended subgrade preparation activities are performed.
For the support of isolated columns using conventional spread footings or continuous
footings or grade beams, structural fill option (Option 1) is recommended; and, moisture
conditioning (Option 2) should not be performed. The subgrade should be prepared as
mentioned in Section 3.7.2, Option 1: Select Fill.
For monolithic, steel reinforced stiffened slab-on-grade foundation system (i.e., a waffle type
grade beam configuration), structural fill option or moisture conditioning should be performed
and the subgrade should be prepared as mentioned in Section 3.7.2.
DENTON PUBLIC TRAINING FACILITY PSI REPORT NO. 03421219
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PROFESSIONAL SERVICE INDUSTRIES, INC. PAGE 13 OF 21
Shallow foundations could be placed at least two feet below the finished grade on properly
compacted structural fill soils and can be designed for a net allowable bearing pressure of 2,400 psf
for dead load plus live loads, and 1,600 psf for dead plus sustained live loads, whichever results in
a larger bearing area.
The grade beams should have a minimum width of 10 inches even if the actual bearing pressure
is less than the design value. The perimeter grade beams should bear at least 24 inches below
adjacent surface grades (i.e. bottoms of beams and pads should bear at least 24 inches below
the adjacent ground surface). If soft or loose soils are encountered at the design bearing level,
they should be undercut to stiff or dense soils and the excavation back-filled with concrete.
Single isolated footing, with width no larger than eight feet, designed as discussed above, should
experience a settlement of less than one inch. If a cluster of closely spaced footings (i.e., if the center
to center spacing of the footings is less than two times the width of the footing) are planned, PSI
should be contacted to calculate the amount of settlement.
The base adhesion/frictional resistance and the passive soil resistance will resist the horizontal
loads on shallow foundations. For a footing cast against natural clay soil or compacted soil, the
adhesion/frictional resistance and the passive soil resistance values for both transient and
sustained loading conditions are given herein. For transient loading conditions, an ultimate base
adhesion resistance of 440 psf and an ultimate passive resistance of 1,600 psf can be used. For
sustained loading conditions, a frictional co-efficient of 0.36 and an ultimate passive resistance of
240 psf per foot depth is recommended. A factor of safety of 2.0 is recommended to arrive at the
allowable values. Passive resistance from the upper two feet of soil should be neglected. Also,
the passive resistance of any un-compacted fill material should be neglected.
The uplift resistance of a shallow foundation formed in an open excavation will be limited to the
weight of the foundation concrete and the soil above it. For design purposes, the ultimate uplift
resistance should be based on effective unit weights of 120 and 150 pcf for soil and concrete,
respectively. This value should then be reduced by an appropriate factor of safety to arrive at the
allowable uplift load. If there is a chance of submergence, the buoyant unit weights should be
used.
The foundation excavations should be observed by a representative of PSI prior to steel or concrete
placement to assess that the foundation materials are capable of supporting the design loads and
are consistent with the materials discussed in this report. Soft or loose soil zones encountered at
the bottom of the footing or grade beam excavations should be removed and replaced with properly
compacted fill as directed by the geotechnical engineer.
After opening, footing or grade beam excavations should be observed and concrete placed as
quickly as possible to avoid exposure of the footing or grade beam bottoms to wetting and drying.
Surface run-off water should be drained away from the excavations and not be allowed to pond. If
possible, the foundation concrete should be placed during the same day the excavation is made. If
it is required that footing or grade beam excavations be left open for more than one day, they should
be protected to reduce evaporation or entry of moisture.
3.7 Floor Slab Recommendations
Based on the subsurface conditions at this site, the soil movements associated with shrink-swell
potential will govern the design of the floor slab. The use of a structurally suspended floor slab
DENTON PUBLIC TRAINING FACILITY PSI REPORT NO. 03421219
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PROFESSIONAL SERVICE INDUSTRIES, INC. PAGE 14 OF 21
system is one appropriate means to isolate the proposed building structure from the underlying
subgrade. If a grade supported floor slab system is desired, remedial earthwork measures should
be performed as described in this section. Detailed geotechnical recommendations are present
below.
3.7.1 Structurally Supported Floor Slab Systems
In order to mitigate the movements associated with soil shrink-swell, it is recommended that the
slab system be structurally suspended above grade on appropriate deep foundation system with
a minimum of 6-inch of void space between the structures (grade beams, pier caps and floor slab
system) and the soil. For structurally suspended slab system, no significant site preparation is
anticipated other than general site grading.
These voids can be produced using compressible cardboard carton forms manufactured
specifically for this purpose. Care should be exercised so that the forms are not crushed, damaged
or allowed to become saturated prior to placement of the concrete. In addition, barriers that will
not rapidly decay should be placed or constructed along the sides of the cardboard carton forms
to prevent soil intrusion into the void after the carton forms decay. Galvanized steel or aluminum
sheet metals are two examples of materials that can be used for this purpose.
3.7.2 Grade Supported Floor Slab Systems
A slab-on-grade floor slab can be constructed provided the site is prepared in accordance with
the recommendations mentioned herein. Based on the subsurface conditions at this project site,
the estimated PVR is on the order of 1 to 2½ inches. Typically, it is the industry practice to consider
1-inch soil movement as the tolerable level for structures of this type. In order to reduce the soil
movements, the following options for subgrade preparation should be followed:
Option 1: Select Fill
In order to reduce the PVR to about one inch and provide uniform support to the floor slab
system, it is recommended that at least 5 feet of low-expansive select fill should be placed below
the floor-slab. The select fill should be placed within the plan area of the structure and to a
distance of at least 5 feet beyond the perimeter of the structure including areas sensitive to
movement such as building entrances and flatwork. Plasticity and compaction requirements for
the select fill are provided in Section 3.3 Site Preparation and Fill Materials of this report.
Option 2: Select Fill and Moisture Conditioned Clay
For this option, in order to reduce the PVR to about one inch and provide uniform support to the
floor slab system, the engineered soil layers are given in Table 3.5.
TABLE 3.5: MOISTURE CONDITION CLAY RECOMMENDATIONS
PVR MATERIAL TYPE LAYER THICKNESS,
FEET
ELEVATION RANGE BELOW
FINISHED GRADE, FEET
1 inch
Select Fill or Flexible Base or
Lime Treated Clay Cap 1 +0 to -1
Moisture Conditioned Clay 6 -1 to -7
Note: Finished Grade Elevation is assumed to be +0 feet.
DENTON PUBLIC TRAINING FACILITY PSI REPORT NO. 03421219
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PROFESSIONAL SERVICE INDUSTRIES, INC. PAGE 15 OF 21
The moisture conditioned soil should be placed within the plan area of the structure and to a
distance of at least five feet beyond the perimeter of the structure and include building entrances
and flatwork sensitive to movements. Placement and compaction requirements are provided in
the Section 3.3 Site Preparation and Fill Materials of this report.
For this option, moisture levels must be maintained throughout the life of the project. It is noted
that if the moisture conditioned clay dries there is possibility for shrinking movements to occur.
Keeping the soils moist can be accomplished by the addition of landscape irrigation and
construction of impermeable surfaces such as the floor and site paving to limit moisture loss.
Larger vegetation should be placed at least the mature height of the vegetation away from the
structure to limit the impact of the root system on the soils supporting the floor slab.
An allowable net bearing pressure of 600 psf can be used for slab-on-grade provided the
subgrade is prepared as recommended above. For the recommended subgrade preparation below
floor slab, a total estimated settlement of less than one inch should be expected under the floor slab.
A vapor retarder such as polyethylene sheeting should be provided directly beneath the ground
supported slab. Adequate construction joints and reinforcement should be provided to reduce the
potential for cracking of the floor slab due to differential movement.
3.8 Seismic Design
The International Building Code (IBC) 2012 edition was used in this report. As part of this code,
the design of structures must consider dynamic forces resulting from seismic events. These forces
are dependent upon the magnitude of the earthquake event, as well as, the properties of the soils
that underlie the site.
Part of the IBC code procedure to evaluate seismic forces requires the evaluation of the Seismic
Site Class, which categorizes the site based upon the characteristics of the subsurface profile
within the upper 100 feet of the ground surface. To define the Seismic Site Class for this project,
we have interpreted the results of our test borings drilled within the project site and estimated
appropriate soil properties below the base of the borings, as permitted by the code. The estimated
soil properties were based upon data available in published geologic reports as well as our
experience with subsurface conditions in the general site area. Based upon the evaluation, the
subsurface conditions within the site are consistent with the characteristics of the Specific Site
Class C as defined in the building code.
DENTON PUBLIC TRAINING FACILITY PSI REPORT NO. 03421219
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PROFESSIONAL SERVICE INDUSTRIES, INC. PAGE 16 OF 21
4.0 PAVEMENT RECOMMENDATIONS
4.1 Subgrade Soil Preparation
Based on subsurface soil information, PSI recommends that at least the top 8 inches of the surficial
soils be lime stabilized. It is important to note that increasing the depth of lime treatment to 12 inches
below the surface will cause significant improvements in the pavement life. Lime treatment should
extend at least one foot outside the perimeter of the pavement. Lime treatment of subgrade soils is
described in Section 3.3 Site Preparation and Fill Materials. If lime stabilization is not desired, 12
inches of select fill can be provided below the pavement materials.
4.2 Pavement Section
AASHTO design methodology can be used to design the pavements. According to AASHTO
design methodology, the pavement design thickness primarily depends on strength of the
subgrade soils and type of traffic. Traffic includes several types of vehicles with various
magnitudes of axle loads that may be subjected to the pavement during its service life. The
design involves a traffic analysis that converts various types of vehicles with various magnitudes
axle loads to a number of 18-kip equivalent single axle load (ESAL) repetitions. The design
engineer should perform the traffic analyses to compute the number of ESALs repetitions that
would be subjected to the pavement during its service life or design life. Based on the computed
ESALs, an economical and appropriate pavement can be designed accordingly.
AASHTO low volume design methodology can also be used to design pavements. The low
volume design methodology depends on typical subgrade conditions for 6 different U.S climatic
zones and provides minimum thickness for 3 different levels of traffic.
Based on AASHTO low volume design and our previous experience, we have provided pavement
thickness for both flexible pavement and rigid pavement systems in tables 4.1 and 4.2 below. The
tables include thickness design corresponding to 3 levels of traffic (low, medium and high). It is
recommended that the pavement design thicknesses correspond to following:
Low traffic condition: Parking areas expected to receive only car traffic.
Medium traffic condition: Secondary drive areas and/or parking areas expected to receive
delivery vans, light trucks, and busses.
High traffic condition: Parking and drive areas with heavy or frequent traffic, fire lanes, trash
pickup areas, main access drive ways, and 18-wheeler loading/unloading.
TABLE 4.1: MINIMUM RIGID PAVEMENT SECTION
PAVEMENT MATERIAL(S) DESIGN THICKNESS
LOW MEDIUM HIGH
Portland Cement Concrete 5.0 inches 6.0 inches 7.0 inches
Pavement Subgrade As Discussed in Section 4.1
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TABLE 4.2: MINIMUM FLEXIBLE PAVEMENT SECTION
PAVEMENT MATERIAL(S) DESIGN THICKNESS
LOW MEDIUM HIGH
Hot Mix Asphalt Concrete
Item 340 TXDOT-Type D 2.0 inches 2.0 inches 3.0 inches
Granular Base Material
Item 247. TXDOT-Type A or D, Grade 1 or 2 6.0 inches 8.0 inches 8.0 inches
Pavement Subgrade As Discussed in Section 4.1
Large front-loading garbage trucks frequently impose concentrated front-wheel loads on
pavements during loading. This type of loading typically results in rutting of the pavement and
ultimately, pavement failures. Therefore, it is recommended that the pavement in trash pickup
areas consist of a minimum 7-inch thick, reinforced concrete slab.
During the construction phase of this project, site grading should be kept in such a way that the
water drains freely off the construction areas.
Proper finishing of concrete pavements requires the use of sawed and sealed joints. Construction
joints should be designed in accordance with current Portland Cement Association guidelines.
Joints should be sealed to reduce the potential for water infiltration into pavement joints and
subsequent infiltration into the supporting soils. Joint spacing is recommended at 15-foot intervals
for plain concrete. Dowel bars should be used to transfer loads at the transverse joints. Normal
periodic maintenance will be required.
The design of steel reinforcement should be in accordance with accepted codes. The concrete
should have a minimum compressive strength of 3,500 psi at 28 days. The concrete should also
be designed with 5 1 percent entrained air to improve workability and durability. Pavement
materials and construction procedures should conform to TXDOT or appropriate city and county
requirements.
Surface water infiltration to the pavement subgrade layers may soften the subgrade soils.
Considering several factors in the pavement design can reduce surface infiltration. The following
are some of the factors that need to be emphasized in order to maintain proper drainage.
1) Appropriate slopes should be provided to drain the water freely away from the pavement
surface.
2) Joints should be properly sealed and maintained.
3) Side drains or sub drains along a pavement section may be provided.
4) Proper pavement maintenance programs such as sealing surface cracks, and immediate
repair of distressed pavement areas should be adopted.
5) If a curb and gutter system is used, the curb should extend through the base and at least
3 inches into the subgrade. This will help reduce migration of subsurface water into the
pavement base course from adjacent areas.
DENTON PUBLIC TRAINING FACILITY PSI REPORT NO. 03421219
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PROFESSIONAL SERVICE INDUSTRIES, INC. PAGE 18 OF 21
5.0 CONSTRUCTION CONSIDERATIONS
5.1 Secondary Design Considerations
The following information has been developed after review of numerous problems concerning
foundations throughout the area. It is presented here for your convenience. If these features are
incorporated in the overall design and specifications for the project, performance of the project
will be improved.
1. Prior to construction, the area to be covered by building should be prepared so that water
will not pond beneath or around the building after periods of rainfall. In addition, water
should not be allowed to pond on or around pavements.
2. Roof drainage should be collected and transmitted by pipe to a storm drainage system or
to an area where the water can drain away from buildings and pavements without entering
the soils supporting buildings and pavements.
3. Sidewalks should not be structurally connected to buildings. They should be sloped away
from buildings so that water will be drained away from structures.
4. Paved areas and the general ground surface should be sloped away from buildings on all
sides so that water will always drain away from the structures. Water should not be allowed
to pond near buildings after the floor slabs and foundations have been constructed.
5. Backfill for utility lines that are located in pavement, sidewalk and building areas should
consist of on-site fill. The backfill should be compacted as described in the Site Preparation
and Fill Materials section of this report. Lesser lift thicknesses may be required to obtain
adequate compaction.
6. Care should be exercised to make sure that ditches for utility lines do not serve as conduits
that transmit water beneath structures or pavements. The top of the ditch should be sealed
to inhibit the inflow of surface water during periods of rainfall.
7. Flower beds and planting areas should not be constructed along building perimeters.
Constructing sidewalks or pavements adjacent to buildings would be preferable. If
required, flower beds and planting areas could be constructed beyond the sidewalks away
from the buildings. If it is desired to have flower beds and planting areas adjacent to a
building, the use of above grade concrete box planters, or other methods that reduce the
likelihood of large changes in moisture content of soils adjacent to or below structures
should be considered.
8. Water sprinkling systems should not be located where water will be sprayed onto building
walls and subsequently drain downward and flow into the soils beneath foundations.
9. Trees in general should not be planted closer to a structure than the mature height of the
tree. A tree planted closer to a structure than the recommended distance may extend its
roots beneath the structure, allowing removal of subgrade moisture and/or causing
structural distress.
10. Utilities that project through slab-on-grade floors should be designed with some degree of
flexibility and/or with a sleeve to reduce the potential for damage to the utilities should
movement occur.
DENTON PUBLIC TRAINING FACILITY PSI REPORT NO. 03421219
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PROFESSIONAL SERVICE INDUSTRIES, INC. PAGE 19 OF 21
11. Soil supported floor slabs are subject to vertical movements. This often causes distress to
interior wall partitions supported on soil supported floor slabs. This should be considered
in the design of soil supported floor slabs.
5.2 Construction Materials Testing
It is recommended that PSI be retained to provide observation and testing of construction
activities involved in the foundations, earthwork, and related activities of this project. PSI cannot
accept any responsibility for any conditions that deviates from those described in this report, nor
for the performance of the foundations if not engaged to also provide construction observation
and testing for this project.
Observation of all foundation bearing materials, peir construction activities, structural steel and
subgrade treatment operations should be performed by a representative of PSI. Density testing
should be performed at a rate of one per 2,500 square feet per 8-inch lift in building areas, one
test per 10,000-square feet per 8-inch lift in paved areas and 1 per 100 linear feet per 8-inch lift
in utility trench backfill. A moisture-density relationship (Proctor), Atterberg’s limit and minus 200
sieve test should be performed for each material encountered at finished subgrade elevation.
5.3 Moisture Sensitive Soils/Weather Related Concerns
The upper fine-grained soils discovered at this site could be sensitive to disturbances caused by
construction traffic and changes in moisture content. During wet weather periods, increases in
the moisture content of the soil can cause significant reduction in the soil strength and support
capabilities. In addition, soils that become wet may be slow to dry and thus significantly retard the
progress of grading and compaction activities. Construction schedules should account for these
conditions during wetter times of the year.
5.4 Drainage and Groundwater Concerns
Water should not be allowed to collect in the foundation excavation, on floor slab areas, or on
prepared subgrades of the construction area either during or after construction. Undercut or
excavated areas should be sloped toward one corner to facilitate removal of any collected
rainwater, ground water, or surface runoff. Positive site surface drainage should be provided to
reduce infiltration of surface water around the perimeter of the building and beneath the floor
slabs. The grades should be sloped away from the building and surface drainage should be
collected and discharged such that water is not permitted to infiltrate the backfill and floor slab
areas of the building.
PSI recommends that the contractor determine the actual ground water levels at the site at the
time of the construction activities. It may be expedient to drill auger holes or excavate test pits
adjacent to the building area immediately prior to construction to determine the prevailing water
level elevation. Any water accumulation should be removed from excavations by pumping. Should
excessive and uncontrolled amounts of seepage occur, the geotechnical engineer should be
consulted.
5.5 Excavations
In Federal Register, Volume 54, No. 209 (October 1989), the United States Department of Labor,
Occupational Safety and Health Administration (OSHA) amended its "Construction Standards for
DENTON PUBLIC TRAINING FACILITY PSI REPORT NO. 03421219
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PROFESSIONAL SERVICE INDUSTRIES, INC. PAGE 20 OF 21
Excavations, 29 CFR, part 1926, Subpart P". This document was issued to better insure the safety
of workmen entering trenches or excavations. It is mandated by this federal regulation that
excavations, whether they be utility trenches, basement excavation or footing excavations, be
constructed in accordance with the new OSHA guidelines. It is our understanding that these
regulations are being strictly enforced and if they are not closely followed the owner and the
contractor could be liable for substantial penalties.
The contractor is solely responsible for designing and constructing stable, temporary excavations
and should shore, slope, or bench the sides of the excavations as required to maintain stability of
both the excavation sides and bottom. The contractor's "responsible person", as defined in 29
CFR Part 1926, should evaluate the soil exposed in the excavations as part of the contractor's
safety procedures. In no case should slope height, slope inclination, or excavation depth,
including utility trench excavation depth, exceed those specified in local, state, and federal safety
regulations.
We are providing this information solely as a service to our client. PSI does not assume
responsibility for construction site safety or the contractor's or other party’s compliance with local,
state, and federal safety or other regulations.
DENTON PUBLIC TRAINING FACILITY PSI REPORT NO. 03421219
4111 VINTAGE BOULEVARD, DENTON, TEXAS SEPTEMBER 2, 2016
PROFESSIONAL SERVICE INDUSTRIES, INC. PAGE 21 OF 21
6.0 REPORT LIMITATIONS
The recommendations submitted in this report are based on the available subsurface information
obtained by PSI and design details furnished by the client for the proposed developments at
Denton Public Training Facility in Denton, Texas. If there are any revisions to the plans for this
project, or if deviations from the subsurface conditions noted in this report are encountered during
construction, PSI should be notified immediately to determine if changes in the foundation
recommendations are required. If PSI is not notified of such changes, PSI will not be responsible
for the impact of those changes on the project.
The geotechnical engineer warrants that the findings, recommendations, specifications, or
professional advice contained herein have been made in accordance with generally accepted
professional geotechnical engineering practices in the local area. No other warranties are implied
or expressed. This report may not be copied, except in the entirety, without expressed written
permission from PSI. PSI is not responsible for any claims, damages, or liability associated with
the interpretation or re-use of the subsurface data or engineering analysis or the conclusions or
recommendations of others based on the findings and recommendations presented herein.
After the plans and specifications are more complete, the geotechnical engineer should be
retained and provided the opportunity to review the final design plans and specifications to check
that our engineering recommendations have been properly incorporated into the design
documents. At that time, it may be necessary to submit supplementary recommendations. If PSI
is not retained to perform these functions, PSI will not be responsible for the impact of those
conditions on the project. This geotechnical report has been prepared for the exclusive use of the
City of Denton and their representatives for the specific application of the proposed Denton Public
Training Facility in Denton, Texas.
DENTON PUBLIC TRAINING FACILITY PSI REPORT NO. 03421219
4111 VINTAGE BOULEVARD, DENTON, TEXAS SEPTEMBER 2, 2016
PROFESSIONAL SERVICE INDUSTRIES, INC.
APPENDIX A
N
Site Vicinity Map
PSI Project No.: 03421219
Project Site
Denton Public Training Facility
4111 Vintage Boulevard
Denton, Texas310 Regal Row, Suite 500
Dallas, Texas 75247
PHONE: (214) 330-9211 –FAX: (214) 333-2853
310 Regal Row, Suite 500
Dallas, Texas 75247
PHONE: (214) 330-9211 –FAX: (214) 333-2853
Aerial Plan
with Boring Location
PSI Project No.: 03421219
N
2015 Aerial Photo
Denton Public Training Facility
4111 Vintage Boulevard
Denton, Texas
310 Regal Row, Suite 500
Dallas, Texas 75247
PHONE: (214) 330-9211 –FAX: (214) 333-2853
Aerial Plan
with Boring Location
PSI Project No.: 03421219
N
2015 Aerial Photo
Denton Public Training Facility
4111 Vintage Boulevard
Denton, Texas
25
21
16
17
18
16
6
15
25
27
28
113
95
97
78
FAT CLAY (CH), very stiff to hard, dark brown
LEAN CLAY (CL), hard, brown, with calcareous
deposits
-with sand and gravel seams below 18.5 feet
8.39
20
56
24
53
46
45
28
19
17
LL UNIT DRY WT.(PCF)COMPRESSIVESTRENGTH (tsf)LOG OF BORING B-101
GROUND WATER DURING DRILLING: Not Encountered
GROUND WATER AFTER DRILLING: Dry
DELAYED GROUND WATER: N/A
DATE DRILLED: 8/22/16
DEPTH TO GROUND WATERPLASTICITY INDEXPL PI
UUUCSOIL TYPE% PASSING#200 SIEVEDESCRIPTION
DEPTH OF BORING: 25 FEET PLASTICLIMITCOORDINATE (X) OR EASTING:
COORDINATE (Y) OR NORTHING:
LATITUDE:
LONGITUDE:
APPROX. SURFACE ELEVATION:
TYPE OF BORING: SOLID FLIGHT AUGER
LOCATION: See Boring Location Plan PSI Project No.: 03421219
Denton Public Training Facility4111 Vintage Boulevard, Denton, Texas
LIQUIDLIMITGeotechnical Consulting Services
310 Regal Row, Suite 300Dallas, TX 75247 SPT - NTCP - T(BLOWS/FT.)0 1 2 3 4 5SAMPLES
NOTES:
HP
COMPRESSIVE
STRENGTHTONS/SQ.FT.MOISTURECONTENT (%)DEPTH, FT.BL_DALLAS - PSIHOUSTON.GDT - 9/2/16 15:47 - P:\0342 DALLAS GEO\2016 GEO PROJECTS\03421219 DENTON PUBLIC TRAINING FACILITY, DENTON, TX - CITY OF DENTON - FACILITIES MANAGEMENT\APPENDIX\03421219.GPJ0
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24
121
78
98
FAT CLAY (CH), stiff to hard, dark brown
LEAN CLAY (CL), very stiff to hard, brown, with
calcareous deposits
-with sand seams at 17 feet
8.84
22
16
32
42
41
17
17
LL UNIT DRY WT.(PCF)COMPRESSIVESTRENGTH (tsf)LOG OF BORING B-102
GROUND WATER DURING DRILLING: Not Encountered
GROUND WATER AFTER DRILLING: Dry
DELAYED GROUND WATER: N/A
DATE DRILLED: 8/22/16
DEPTH TO GROUND WATERPLASTICITY INDEXPL PI
UUUCSOIL TYPE% PASSING#200 SIEVEDESCRIPTION
DEPTH OF BORING: 25 FEET PLASTICLIMITCOORDINATE (X) OR EASTING:
COORDINATE (Y) OR NORTHING:
LATITUDE:
LONGITUDE:
APPROX. SURFACE ELEVATION:
TYPE OF BORING: SOLID FLIGHT AUGER
LOCATION: See Boring Location Plan PSI Project No.: 03421219
Denton Public Training Facility4111 Vintage Boulevard, Denton, Texas
LIQUIDLIMITGeotechnical Consulting Services
310 Regal Row, Suite 300Dallas, TX 75247 SPT - NTCP - T(BLOWS/FT.)0 1 2 3 4 5SAMPLES
NOTES:
HP
COMPRESSIVE
STRENGTHTONS/SQ.FT.MOISTURECONTENT (%)DEPTH, FT.BL_DALLAS - PSIHOUSTON.GDT - 9/2/16 15:47 - P:\0342 DALLAS GEO\2016 GEO PROJECTS\03421219 DENTON PUBLIC TRAINING FACILITY, DENTON, TX - CITY OF DENTON - FACILITIES MANAGEMENT\APPENDIX\03421219.GPJ0
5
10
15
20
25
30
35
40
45
50
19
13
13
12
12
21
20
9
20
12
106
112
72
57
FAT CLAY (CH), very stiff, dark brown
LEAN CLAY (CL), very stiff to hard, brown, with
calcareous deposits
SANDY LEAN CLAY (CL), stiff to very stiff, tan,
with calcareous deposits
LEAN CLAY (CL), firm to stiff, tan, with calcareous
deposits
POORLY GRADED GRAVEL WITH CLAY
(GP-GC), hard
0.88
0.93
50
36
25
16
13
LL UNIT DRY WT.(PCF)COMPRESSIVESTRENGTH (tsf)LOG OF BORING B-103
GROUND WATER DURING DRILLING: 22 Feet
GROUND WATER AFTER DRILLING: 22 Feet
DELAYED GROUND WATER: N/A
DATE DRILLED: 8/22/16
DEPTH TO GROUND WATERPLASTICITY INDEXPL PI
UUUCSOIL TYPE% PASSING#200 SIEVEDESCRIPTION
DEPTH OF BORING: 25 FEET PLASTICLIMITCOORDINATE (X) OR EASTING:
COORDINATE (Y) OR NORTHING:
LATITUDE:
LONGITUDE:
APPROX. SURFACE ELEVATION:
TYPE OF BORING: SOLID FLIGHT AUGER
LOCATION: See Boring Location Plan PSI Project No.: 03421219
Denton Public Training Facility4111 Vintage Boulevard, Denton, Texas
LIQUIDLIMITGeotechnical Consulting Services
310 Regal Row, Suite 300Dallas, TX 75247 SPT - NTCP - T(BLOWS/FT.)0 1 2 3 4 5SAMPLES
NOTES:
HP
COMPRESSIVE
STRENGTHTONS/SQ.FT.MOISTURECONTENT (%)DEPTH, FT.BL_DALLAS - PSIHOUSTON.GDT - 9/2/16 15:47 - P:\0342 DALLAS GEO\2016 GEO PROJECTS\03421219 DENTON PUBLIC TRAINING FACILITY, DENTON, TX - CITY OF DENTON - FACILITIES MANAGEMENT\APPENDIX\03421219.GPJ0
5
10
15
20
25
30
35
40
45
50
16
16
16
5
FAT CLAY (CH), dark brown, very stiff
LEAN CLAY (CL), brown, very stiff to hard, with
calcareous deposits
SANDY LEAN CLAY (CL), tan, stiff to very stiff,
with calcareous deposits
LEAN CLAY (CL), tan, firm to stiff, with calcareous
deposits
SANDY LEAN CLAY (SC), hard, gray and tan
-gravel at 30 feet
FAT CLAY (CH), hard, gray and tan, shaley, with
gravel
SHALE, hard, gray
136.50
135.60
T:100(1.5")
T:100(1")
T:100(0.75")
LL UNIT DRY WT.(PCF)COMPRESSIVESTRENGTH (tsf)LOG OF BORING B-201
GROUND WATER DURING DRILLING: Not Encountered
GROUND WATER AFTER DRILLING: Dry
DELAYED GROUND WATER: N/A
DATE DRILLED: 8/31/16
DEPTH TO GROUND WATERPLASTICITY INDEXPL PI
UUUCSOIL TYPE% PASSING#200 SIEVEDESCRIPTION
DEPTH OF BORING: 55 FEET PLASTICLIMITCOORDINATE (X) OR EASTING:
COORDINATE (Y) OR NORTHING:
LATITUDE:
LONGITUDE:
APPROX. SURFACE ELEVATION:
TYPE OF BORING: SOLID FLIGHT AUGER
LOCATION: See Boring Location Plan PSI Project No.: 03421219
Denton Public Training Facility4111 Vintage Boulevard, Denton, Texas
LIQUIDLIMITGeotechnical Consulting Services
310 Regal Row, Suite 300Dallas, TX 75247 SPT - NTCP - T(BLOWS/FT.)0 1 2 3 4 5SAMPLES
NOTES:
HP
COMPRESSIVE
STRENGTHTONS/SQ.FT.MOISTURECONTENT (%)DEPTH, FT.BL_DALLAS - PSIHOUSTON.GDT - 9/2/16 15:47 - P:\0342 DALLAS GEO\2016 GEO PROJECTS\03421219 DENTON PUBLIC TRAINING FACILITY, DENTON, TX - CITY OF DENTON - FACILITIES MANAGEMENT\APPENDIX\03421219.GPJ0
5
10
15
20
25
30
35
40
45
50
LIMESTONE, very hard, gray
156.00T:100(0.50")
LL UNIT DRY WT.(PCF)COMPRESSIVESTRENGTH (tsf)LOG OF BORING B-201
GROUND WATER DURING DRILLING: Not Encountered
GROUND WATER AFTER DRILLING: Dry
DELAYED GROUND WATER: N/A
DATE DRILLED: 8/31/16
DEPTH TO GROUND WATERPLASTICITY INDEXPL PI
UUUCSOIL TYPE% PASSING#200 SIEVEDESCRIPTION
DEPTH OF BORING: 55 FEET PLASTICLIMITTYPE OF BORING: SOLID FLIGHT AUGER
LOCATION: See Boring Location Plan PSI Project No.: 03421219
Denton Public Training Facility4111 Vintage Boulevard, Denton, Texas
LIQUIDLIMITGeotechnical Consulting Services
310 Regal Row, Suite 300Dallas, TX 75247 SPT - NTCP - T(BLOWS/FT.)0 1 2 3 4 5SAMPLES
NOTES:
HP
COMPRESSIVE
STRENGTHTONS/SQ.FT.MOISTURECONTENT (%)DEPTH, FT.BL_DALLAS - PSIHOUSTON.GDT - 9/2/16 15:47 - P:\0342 DALLAS GEO\2016 GEO PROJECTS\03421219 DENTON PUBLIC TRAINING FACILITY, DENTON, TX - CITY OF DENTON - FACILITIES MANAGEMENT\APPENDIX\03421219.GPJ50
55
60
65
70
75
80
85
90
95
100
24
21
24
13
14
14
10
11
11
17
21
127
FILL - FAT CLAY, very stiff, brown
LEAN CLAY (CL), hard, light brown and gray
-with calcareous deposits above 10 feet
-with sand below 20 feet
SHALE, soft to hard, gray
9.43
T:100(1.25")
T:100(5.5")
LL UNIT DRY WT.(PCF)COMPRESSIVESTRENGTH (tsf)LOG OF BORING B-202
GROUND WATER DURING DRILLING: 30.5 Feet
GROUND WATER AFTER DRILLING: 29.5 Feet
DELAYED GROUND WATER: N/A
DATE DRILLED: 8/31/16
DEPTH TO GROUND WATERPLASTICITY INDEXPL PI
UUUCSOIL TYPE% PASSING#200 SIEVEDESCRIPTION
DEPTH OF BORING: 40 FEET PLASTICLIMITCOORDINATE (X) OR EASTING:
COORDINATE (Y) OR NORTHING:
LATITUDE:
LONGITUDE:
APPROX. SURFACE ELEVATION:
TYPE OF BORING: SOLID FLIGHT AUGER
LOCATION: See Boring Location Plan PSI Project No.: 03421219
Denton Public Training Facility4111 Vintage Boulevard, Denton, Texas
LIQUIDLIMITGeotechnical Consulting Services
310 Regal Row, Suite 300Dallas, TX 75247 SPT - NTCP - T(BLOWS/FT.)0 1 2 3 4 5SAMPLES
NOTES:
HP
COMPRESSIVE
STRENGTHTONS/SQ.FT.MOISTURECONTENT (%)DEPTH, FT.BL_DALLAS - PSIHOUSTON.GDT - 9/2/16 15:47 - P:\0342 DALLAS GEO\2016 GEO PROJECTS\03421219 DENTON PUBLIC TRAINING FACILITY, DENTON, TX - CITY OF DENTON - FACILITIES MANAGEMENT\APPENDIX\03421219.GPJ0
5
10
15
20
25
30
35
40
45
50
CONSISTENCY N-VALUE
(Blows/Foot)
SHEAR STRENGTH
(tsf)
HAND PEN VALUE
(tsf)
Very Soft 0 TO 2 0 TO 0.125 0 TO 0.25
Soft 2 TO 4 0.125 TO 0.25 0.25 TO 0.5
Firm 4 TO 8 0.25 TO 0.5 0.5 TO 1.0
Stiff 8 TO 15 0.5 TO 1.0 1.0 TO 2.0
Very Stiff 15 TO 30 1.0 TO 2.0 2.0 TO 4.0
Hard >30 >2.0 OR 2.0+ >4.0 OR 4.0+
KEY TO TERMS AND SYMBOLS USED ON LOGS
CONSISTENCY OF COHESIVE SOILS
DESCRIPTION OF ROCK
QUALITY RQD
Very Poor (VPo) 0 TO 25
Poor (Po) 25 TO 50
Fair (F) 50 TO 75
Good (Gd) 75 TO 90
Excellent (ExInt) 90 TO 100
ROCK QUALITY DESIGNATION
(RQD)
DESCRIPTION OF
RECOVERY
% CORE
RECOVERY
Incompetent < 40
Competent 40 TO 70
Fairly Continuous 70 TO 90
Continuous 90 TO 100
RECOVERY
ROCK CLASSIFICATION
DENSITY (GRANULAR) CONSISTENCY (COHESIVE) THD (BLOWS/FT) FIELD IDENTIFICATION
Very Loose (VLo) Very Soft (VSo) 0 TO 8 Core (height twice diameter) sags under own weight
Loose (Lo) Soft (So) 8 TO 20 Core can be pinched or imprinted easily
with finger
Slightly Compact
(SICmpt) Stiff (St) 20 TO 40 Core can be imprinted with considerable
pressure
Compact (Cmpt) Very Stiff (VSt) 40 TO 80 Core can only be imprinted slightly with fingers
Dense (De) Hard (H) 80 TO 5”/100 Core cannot be imprinted with fingers but
can be penetrated with pencil
Very Dense (VDe) Very Hard (VH) 5”/100 to 0”/100 Core cannot be penetrated with pencil
SOIL DENSITY OR CONSISTENCY
DEGREE OF PLASTICITY PLASTICITY INDEX (PI) SWELL POTENTIAL
None or Slight 0 to 4 None
Low 4 to 20 Low
Medium 20 to 30 Medium
High 30 to 40 High
Very High >40 Very High
DEGREE OF PLASTICITY OF COHESIVE SOILS
MORHS’ SCALE CHARACTERISTICS EXAMPLES APPROXIMATE THD PEN TEST
5.5 to 10 Rock will scratch knife Sandstone, Chert, Schist, Granite, Gneiss, some Limestone Very Hard (VH) 0” to 2”/100
3 to 5.5 Rock can be scratched
with knife blade
Siltstone, Shale, Iron Deposits, most
Limestone Hard (H) 1” to
5”/100
1 to 3 Rock can be scratched with fingernail Gypsum, Calcite, Evaporites, Chalk, some Shale Soft (So) 4” to 6”/100
BEDROCK HARDNESS
DESCRIPTION CONDITION
Absence of moisture, dusty, dry to touch DRY
Damp but no visible water MOIST
Visible free water WET
MOISTURE CONDITION OF COHESIVE SOILS
U.S. STANDARD SIEVE SIZE(S)
6"3"3/4"4 10 200
GRAVEL SAND
152 76.2 19.1 4.76 2.0 0.42 0.074 0.002
GRAIN SIZE IN MM
SILT OR CLAY CLAYFINE
40
COARSE FINE COARSE MEDIUMCOBBLESBOULDERS
SAMPLER TYPES SOIL TYPES
APPARENT DESNITY SPT (BLOWS/FT)
CALIFORNIA
SAMPLER
(BLOWS/FT)
MODIFIED CA.
SMAPLER
(BLOWS/FT)
RELATIVE DENSITY (%)
Very Loose 0 to 4 0 to 5 0 to 4 0 to 15
Loose 4 to 10 5 to 15 5 to 12 15 to 35
Medium Dense 10 to 30 15 to 40 12 to 35 35 to 65
Dense 30 to 50 40 to 70 35 to 60 65 to 85
Very Dense >50 >70 >60 85 to 100
RELATIVE DENSITY FOR GRANULAR SOILS
ABBREVIATIONS
CLASSIFICATION OF GRANULAR SOILS
PL –Plastic Limit
LL –Liquid Limit
WC –Percent Moisture
QP –Hand Penetrometer
QU –Unconfined Compression Test
UU –Unconsolidated Undrained Triaxial
Note: Plot Indicates Shear Strength as Obtained By Above TestsINITIAL GROUND WATER
FINAL GROUND WATER
CONSISTENCY OF ROCK CORES
CONSISTENCY UNCONF. COMP.
STRENGTH IN TSF
Very Soft 10 TO 250
Soft 250 TO 500
Hard 500 TO 1000
Very Hard 1000 TO 2000
Extra Hard >2000
DENTON PUBLIC TRAINING FACILITY PSI REPORT NO. 03421219
4111 VINTAGE BOULEVARD, DENTON, TEXAS SEPTEMBER 2, 2016
PROFESSIONAL SERVICE INDUSTRIES, INC.
APPENDIX B
Jff Information M[To Build On m Engineering • Consulting • Testing
June 24, 2008
City of Denton
215 E. McKinney Street
Denton, Texas 76201
Attention: Mr. Herman Lawson
RE: Addendum to Geotechnical Engineering Services Report
Proposed Public Training Facility
4111 Vintage Boulevard
Denton, Texas PSI Project No.: 342-85019 Addendum 1
Dear Mr. Lawson:
As requested by Mr. Roger LeBoeuf of Elliott, LeBoeuf & McElwain Engineering,
Professional Service Industries, Inc. (PSI) is pleased to submit this addendum to our
original geotechnical report for the above referenced project. This addendum report
should be read in conjunction with our original geotechnical report dated April 8, 2008,
and PSI report number 342-85019. Based on the new information provided by Mr. Roger
LeBoeuf, maximum wall loads are 15 kips per linear foot, with typical wall loads between 4
laps per linear foot and 10 kips per linear foot. Maximum column loads are understood to be
360 kips. The structural systems are reinforced concrete slabs supported on load bearing
masonry walls. Also, Mr. Roger LeBoeuf requested PSI to provide:
• A straight shaft driller pier recommendation
® The lateral load design parameters
® Pier uplift force resisting capacity to resist overturning loads
® Earth pressure and other design criteria for retaining walls
• A reduced pier cluster spacing
Straight Shaft Drilled Pier Recommendations
Consideration may be given to supporting the building loads on straight shaft drilled piers
as requested by Mr. Roger LeBoeuf. We understand that maximum column loads are 360
kips. Based on the subsurface conditions encountered, weathered gray shale was not
present at all the boring locations and PSI strongly recommends verifying the depth to the
weathered gray shale by performing two (2) additional deep borings to a minimum depth
of 15 feet into the weathered gray shale or to a total depth of 55 feet. A minimum
penetration of 15 feet into the weathered gray shale is recommended verify the bearing
capacity of the weathered gray shale below the calculated pier penetrations.
Public Training Facility
PSI Project No.: 342-85019 Addendum 1 June 24, 2008
Page 1 of 8
Professional Service Industries, Inc. • 4087 Shilling Way • Dallas, TX 75237 * Phone 214/330-9211 • Fax 214/333-2853
The straight shaft piers should extend to and penetrate a minimum of 2 feet or 1.5 times
the pier diameter, whichever is more, into gray shale. Deeper penetrations may be
required to develop skin friction for support of the structure loads. Skin friction resistance
and shaft reinforcement will also be required to resist any uplift loads that may be exerted
on the shafts due to live loads and due to swelling of overburden clays. The piers will
utilize a combination of end bearing and skin friction within the gray shale to develop
load carrying capacity.
Piers founded in the referenced materials may be proportioned assuming a maximum
allowable end bearing pressure of 23,000 pounds per square foot based on dead load plus
design live load considerations. The piers may also be designed for an allowable skin
friction value of 2,500 pounds per square foot based on dead load plus design live load
considerations for that portion of the pier in contact with gray shale. In no case should
piers be designed with a shaft diameter less than 12 inches. Piers should have a minimum
clear spacing at least equal to or larger than twice the diameter of the largest adjacent
pier. Settlements of properly constructed shafts situated in the referenced bearing
materials are expected to be less than 1/4 inch.
The design values provided are intended to provide a minimum factor of safety of three
or greater. Slightly lower factors of safety may be considered for temporary loading
conditions such as wind loads. The piers should be reinforced for their full depth to resist
potential tensile forces that may develop due to swelling of the site soils and due to
structural loads. Uplift forces due to swelling soils can be approximated by assuming an
uplift adhesion value of 1,500 pounds per square foot over the perimeter of the shaft for a
depth of 15 feet. The uplift force on each pier will be resisted by the dead load on the pier
and side friction on the portion of the pier in contact with the gray shale.
It is recommended that the design and construction of drilled piers should generally
follow methods outlined in the manual titled Drilled Shafts: Construction Procedures and
Design Methods (Publication No: FHWA-IF-99-025, August 1999).
Detailed inspection of pier construction should be made to verify that the piers are
vertical and founded in the proper bearing stratum, and to verify that all loose materials
have been removed prior to concrete placement. Sandy material is encountered in the site
and can be causing of pier holes caving during pier construction. Temporary casing,
although not anticipated, must be used where necessary to stabilize pier holes and to
reduce water inflow. Any accumulated water must be removed prior to the placement of
concrete. A hopper and tremie should be utilized during concrete placement to control the
maximum free fall of the wet concrete to less than five feet unless the mix is designed so
that it does not segregate during free fall and provided the pier excavation is dry.
Shafts should be clean and be free of all loose materials prior to placement of concrete.
The drilled shafts should be installed in accordance with Item 416 of TxDOT
specifications or in accordance with the guidelines provided in FHWA-IF-99-025. A PSI
representative should verify the bearing stratum, bearing depth, bearing soil condition,
bearing area and that the pier installation procedures meet the specifications.
Public Training Facility
PSI Project No.: 342-85019 Addendum 1
June 24, 2008
Page 2 of 8
During our field operations, ground water was found at a depth of 16 feet below the
ground surface. Therefore, drilled shaft excavations installed below 16 feet depth will
experience ground water infiltration. If more than four inches of water is collected in the
open shaft excavation in less than one-half hour, we recommend casing to minimize the
seepage.
The successful completion of drilled pier excavations will depend, to a large extent, on
the suitability of the drilling equipment together with the skill of the operator. The
sequence of operations should be scheduled so that each pier can be drilled, reinforcing
steel placed, and the concrete poured in a continuous, rapid, and orderly manner to reduce
the time that the excavation is open.
Shafts should be clean and be free of all loose materials prior to placement of concrete.
The drilled shafts should be installed in accordance with Item 416 of TxDOT
specifications or ACI 336.1 Specifications or in accordance with the guidelines provided
in FHWA-IF-99-025. We recommend a PSI representative should verify the bearing
stratum, bearing depth, bearing soil condition, bearing area and that the pier installation
procedures meet the specifications.
Lateral Load Design Parameter
For drilled shafts, the soil as well as the rigidity of the shaft resists the lateral loads on the
shaft. Once the locations, loads and other pertinent information are provided, PSI can
assist in performing lateral load analyses based on methods ranging from chart solutions
to the 'p-y' approach utilizing computer programs such as LPILE or COM 624. The
lateral loads on the shaft can also be designed based on the criteria provided in the
FHWA-Drilled Shaft Manual.
The lateral design information regarding the 'p-y' data is provided in Table 1. The
relationship between the soil resistance (p) and pile deflection (y) is commonly referred
to as 'p-y'. Along the depth of the shaft, soil resistance (p) is expressed as a non-linear
function of lateral shaft deflection (y). Various researchers developed 'p-y' criteria for
different kinds of soils. The 'p-y' curves can be automatically generated utilizing the
computer program LPILE. The program LPILE was developed by Lymon Reese and
Shin-Tower Wang, Ensoft, Inc. 'p-y' parameters for LPILE analyses are provided for the
analyses of individual shafts.
Public Training Facility
PSI Project No. : 342-85019 Addendum 1
June 24, 2008
Page 3 of 8
Table 1: Soil Parameters to be used in the Lateral Load Analyses
Effective Unit Su orQu
(psf), or Ks (pci) or
Kc (pci) or Ssoor Weight, y Stratum 'p-y' Criteria Km <j) (degrees) E (psi) (pcf)
Stiff Clay Ks = 500
Kc = 200 I* (Oto 15) Su = 2,000 Eso = 0.007 125 Criteria
Ks =1000
Kc = 400
Stiff Clay ES0 = 0.005 Su = 4,000 II (15 to 35) 125 Criteria
Soft Rock Qu = 23,000 E = 8,000 krm = 0.0005 145 III (35 to 40) Criteria
Note: Su-Undrained Shear Strength (tsf); Qu-Uneonfined Compressive Strength (tsf); <)),
Angle of Internal friction; ks-modulus of subgrade reaction (pci) for static loading
condition; lcc-modulus of subgrade reaction (pci) for cyclic loading condition; E-
Young's modulus (psi); 850- strain corresponding to one-half the principle stress.
krm _ a constant for overall stiffness.
* Neglect the upper 5 feet of Stratum I soils for the lateral load analysis.
Retaining Wall/Below Grade Wall Design and Construction
Below-grade walls may be required to resist lateral earth pressures. These may include
basement walls, loading dock walls and retaining or wing walls designed to
accommodate surface grade changes around the building and parking areas, adjacent to
truck ramps, or retaining walls.
Retaining walls such as deep grade beams or walls in depressed truck dock areas
constructed, as part of the building structure should be supported on foundations that
match the foundations used for the building. Any freestanding retaining walls not
associated with the building may be supported on either drilled pier or shallow
foundations. Recommendations provided for drilled pier and shallow foundations
supporting the building structure loads can be used for design of retaining wall
foundations.
Recommendations provided for shallow spread footings supporting the building structure
loads can be used for design of retaining wall foundations. The foundation excavations
should be observed by a representative of PSI prior to steel or concrete placement to
assess that the foundation materials are capable of supporting the design loads and are
consistent with the materials discussed in this report. After opening, footing excavations
should be observed and concrete placed as quickly as possible to avoid exposure of the
footing bottoms to wetting and (frying. Surface run-off water should be drained away
from the excavations and not be allowed to pond. The foundation concrete should be
Public Training Facility
PSI Project No.: 342-85019 Addendum 1 June 24, 2008 Page 4 of 8
placed during the same day the excavation is made. If it is required that footing
excavations be left open for more than one day, they should be protected to reduce
evaporation or entry of moisture.
Retaining walls may be supported on conventional spread footing foundations bearing on
existing soils or engineered fills at 24 inches below lower adjacent finish grade. Footings
should be designed for allowable soil bearing pressures of 2,500 psf. Movement of the
footings and walls should be anticipated. Solid concrete walls should be battered into the
soil to limit outward rotational movement caused by differential footing movement.
Lateral Earth Pressure
Below-grade walls will be required to resist lateral earth pressures. The actual earth
pressure on the walls will vary according to material types and backfill materials used
and how the backfill is compacted. The equivalent fluid unit weights tabulated below
provide recommended lateral earth pressures for design of these walls. This table
assumes that positive foundation drainage is provided to prevent buildup of hydrostatic
pressure.
TABLE 2 LATERAL EARTH PRESSURES IN TERMS OF EQUIVALENT FLUID PRESSURES
ACTIVE AT REST
BELOW ABOVE BELOW
THE
WATER
TABLE
(PCF)
ASSUMED ABOVE
THE THE THE $ WATER
TABLE*
(PCF)
WATER
TABLE
(PCF)
WATER
TABLE
(PCF)
MATERIAL VALUE
(DEGREES)
In-situ soils are classified as dark 90 45 75 37 15° brown to brown high plasticity clay
In-situ soils are classified as
yellowish brown moderate plasticity 80 40 60 30 20°
clay
Select fill consisting of clayey sand
as previously defined 65 33 45 23 28°
ASTM C33 Fine Aggregate (sub-55 28 35 18 35° angular concrete sand).
ASTM C33 Coarse Aggregate size
67consisting of crushed angular
limestone.
50 25 30 15 38°
In addition to hydrostatic pressure of 62.4 pcf
The coefficient of friction between the base of the concrete anchor blocks and the
subgrade soils of 0.30 is recommended. The ultimate passive earth pressure, in psf, can
be computed by using an equivalent fluid pressure of 240 psf/ft. Passive resistance should
be neglected in the top 5 feet depth due to the possibility of desiccation of the high
plasticity clays.
Public Training Facility
PS1 Project No.: 342-85019 Addendum 1
June 24, 2008
Page 5 of 8 \KSSU
The backfill should stop 2 feet below final grade where the surface is not paved. The
upper two feet should be backfilled with on site clays to reduce surface water inflows into
the backfill. The backfill should be sloped down away from the building.
The backfill materials should be placed in 8-inch thick loose layers and compacted to 95
percent of the standard Proctor maximum dry density according to ASTM D-698. The
backfill directly behind the walls should be compacted with light, hand-held compactors.
Heavy compactors and grading equipment should not be allowed to operate within 5 feet
of the walls during backfilling to avoid developing excessive temporary or long-term
lateral soil pressures. A representative of the geotechnical engineer should be present to
monitor all foundation excavations and fill placement.
The wall backfill limits should extend outward at least 3 feet from the base of the fill and
then upward on a 1H:2V slope. Surcharge loads should be included in the design of any
below grade walls, deep grade beams or retaining walls.
Settlement of the backfill soils should be anticipated. This settlement could affect
sidewalks, drives crossing over the fill soils and utilities. Properly compacted fill soils are
anticipated to settle between 1 to 2 percent of the fill depth. For example, 100 inches of
fill would be expected to settle in the range of 1 to 2 inches. This fill settlement could
result in some movement of flatwork supported on this fill. The fill settlement could also
increase the vertical load on and possible deflection of utilities crossing through the fill.
A vertical wall drainage layer is recommended to prevent hydrostatic pressures from
acting on below grade walls, or retaining walls. Either a 1-foot thick vertical drain or a
drainage panel can be used to control groundwater in select fill or on-site clay backfill.
Free draining sand and gravel backfill does not require a vertical drainage layer. Vertical
sand and gravel drainage layer should meet the requirements given above for wall
backfill. A filter fabric should be placed between the vertical drainage layer and the wall
backfill soils. Alternatively a drainage panel such as Mirafi's Miradrain can be used. A
perforated pipe drain should be installed at the base of the vertical wall drain and be
drained to a sump pump or a gravity drainage system. Weep holes can be used for area
retaining walls.
The above values do not include either factors of safety or the influence of foundation or
surface load in or adjacent to the wall backfill. Below grade walls should also be
designed to resist adjoining surcharge loads from foundations and/or equipment located
in the vicinity of the wall
Site Class and Site Coefficients
Please note that the project site is located within a municipality that employs the
International Building Code (IBC) 2003 edition. As part of this code, the design of
structures must consider dynamic forces resulting from seismic events. These forces are
dependent upon the magnitude of the earthquake event as well as the properties of the
soils that underlie the site.
Public Training Facility
PSI Project No.: 342-85019 Addendum 1
June 24, 2008
Page 6 of 8
Part of the IBC code procedure to evaluate seismic forces requires the evaluation of the
Seismic Site Class, which categorizes the site based upon the characteristics of the
subsurface profile within the upper 100 feet of the ground surface.
To define the Seismic Site Class for this project, we have performed:
® Interpreted the results of our soil test borings drilled within the project site and
estimated appropriate soil properties below the base of the borings to a depth of
100 feet, as permitted by Section 1615.1.1 of the code. The estimated soil
properties were based upon data available in published geologic reports as well as
our experience with subsurface conditions in the general site area.
Based upon our evaluation, it is our opinion that the subsurface conditions within the site
are consistent with the characteristics of the Specific Site Class C as defined in Table
1615.1.1 of the building code.
The USGS-NEHRP probabilistic ground motion values for the site which were obtained
from the USGS geohazards web page (http://eqdesign.cr.usgs.gov/html/design-
lookun.html') are as follows:
2% Probability of Event in
j; 50 years (%g)
Period
(seconds) Site Coefficient Fv Site Coefficient F.
0.109g 1.20 0.2 (Ss)
1.70 1.0 (SQ 0.048g
The Site Coefficients, Fa and Fv presented in the above table were interpolated from IBC
Tables 1615.1.2(1) and 1615.1.2 (2) as a function of the site classification and mapped
spectral response acceleration at the short (Ss) and 1 second (Si) periods.
This ends Addendum No. 1. All other recommendations provided in our original report
dated April 8, 2008 (PSI Project no. 342-85019) remain valid for the proposed
construction. PSI requests an opportunity to review the final plans to confirm our final
recommendations.
Public Training Facility
PSI Project No.: 342-85019 Addendum 1
June 24, 2008
Page 7 of 8 a
We at PSI look forward to working with you in future phases of this project. If you have
any questions concerning this letter, please do not hesitate to contact our office at (214)
330-9211.
Respectfully submitted,
Professional Service Industries, Inc.
0*/ \Vk Arthit Laikram, Ph.D., E.I.T.
$DANNY R,'^ANDERSdNl Graduate Engineer ifi'"*"'""""'"'"""""!-'''# arthit.laikram@psiusa.com %%\ d<£062 /> B
Danny R. Anderson, P.E.
Regional Engineer
danny.anderson@psiusa.com
Public Training Facility
PSi Project No.: 342-85019 Addendum 1
June 24, 2008
Page 8 of 8 ,/j^z