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�' GFA INTERNATIONAL
FLORIDA'S LEADING ENGINEERING SOURCE
Report of Geotechnical Exploration
i
Proposed Two -Story Residence
2001 Nettles Boulevard
St! I. Lucie County, Florida
; i August 29, 2013
GFA Project No.: 13-1849.00
For: JWN Construction
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Environmental - Geotechnical • Construction Materials Testing - Threshold and Special Inspections - Plan Review & Code Compliance
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JWN Construction
Attention: Mr. James Newman
1701 SE Carvalho Street
Port St. Lucie, Florida 34982
Site: Proposed Two -Story Residence
2001 Nettles Boulevard
St. Lucie County, Florida
GFA Project # 13-1849.00
Dear Mr. Newman:
August 29, 2013
GFA International, Inc. (GFA) has completed the subsurface exploration and geotechnical
engineering evaluation for the above -referenced project in accordance with the geotechnical
and engineering service agreement for this project. The scope of services was completed in
accordance with our geotechnical engineering proposal dated August 23, 2013, planned in
conjunction with and authorized by you.
EXECUTIVE SUMMARY
The purpose of our subsurface exploration was to classify the nature of the subsurface soils and
general geomorphic conditions and evaluate their impact upon the proposed construction. This
report contains the results of our subsurface exploration at the site and our engineering
interpretations of these, with respect to the project characteristics described to us including
providing recommendations for site preparation and the design of the foundation system.
Based on conversations with the client, the project consists of constructing a two-story
residence. GFA was informed that piles or a shallow foundation is desired to be used for
support of the structure. We have not received any information regarding structural loads. For
the foundation recommendations presented in this report we assumed the maximum column
load will be 40 kips and the maximum wall loading will be 4 kips per linear foot. GFA estimates
the site is at or near final grade.
The recommendations provided herein are based upon the above considerations. If the project
description has been revised, please inform GFA International so that we may review our
recommendations with respect to any modifications.
A total of two (2) standard penetration test (SPT) borings to depths of approximately fifteen (15)
and forty (40) feet below ground surface (BGS) were completed for this study.
The subsurface soil conditions encountered at this site generally consist of medium dense sand
(SP) to a depth of 4 feet, loose to medium dense sand (SP) from 4 to 131/z feet, medium dense
to dense sand (SP) from 13'/z to 23% feet, silt and clay (ML) from 23% to 28'/z feet, silty/clayey
sand (SM) from 28'/z to 33'/2, and then sand (SP) with trace cemented sand from 33'/z to the
521 NW Enterprise Drive - Port St. Lucie, Florida 34986 - (772) 924.3575 - (772) 924.3580 (fax) - www.teamgfa.com
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j
Proposed Two -Story Residence Geotechnical Report
2001 Nettles Boulevard, St. Lucie County, FL August 29, 2013
GFA Project No. 13-1849.00 Page 2 of 12
boring termination depths. Please refer to Appendix D - Record of Test Borings for a detailed
account of each boring.
GFA was informed that a pile or shallow foundation are desired to be used for support of the
structure.
GFA recommends the deep foundation to consist of augered cast -in -place piles (ACIP). The
ground floor slabs may be supported directly on the existing grade or on granular fill following
the foundation site preparation and fill placement procedures outlined in this report. Based on
our analysis, GFA has estimated that a 14-inch-diameter ACIP pile installed to a depth of 19
feet can provide a maximum allowable axial compressive capacity of 20 tons and a maximum
tension capacity of 6 tons, and a 14-inch-diameter ACIP pile installed to a depth of 32 feet can
provide a maximum allowable axial compressive capacity of 30 tons and a maximum tension
capacity of 9 tons. The pile installation length is based on installing the piles at site grade (grade
even with the adjacent roadway) existing at time of drilling. If additional fill will be required to
raise the site to achieve final grade, the piles will be longer according to the depth of fill added.
The subsurface soil conditions at' the project site are generally favorable for the support of the
proposed structures on shallow foundations. An allowable bearing capacity of 2,500 psf may be
used for foundation design.
For piles and shallow foundation
the stripped grade. The top 2 fe
95% density prior to placing fill tc
placed in 12-inch lifts and comp
footings, the subgrade to a dep
achieve a minimum 95% density
, the subgrade soils should be improved with compaction from
:t below stripped grade should be compacted to a minimum of
achieve final grade. Fill (including stemwall backfill) should be
cted to achieve a minimum 95% density. After excavation for
i of 2 feet below bottom of footings should be compacted to
We appreciate the opportunity to be of service to you on this
continued association. Please do not hesitate to contact us
comments, or if we may further assist you as your plans proceed.
Respectful
GFA Int"
Florida.
....- i
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Copies: 2,
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Number 4930
project and look forward to a
if you have any questions or
David Alker
Project Manager
GF
9
Proposed Two -Story Residence Geotechnical Report
2001 Nettles Boulevard, St. Lucie County, FL August 29, 2013
GFA Project No. 13-1849.00 Page 3 of 12
TABLE OF CONTENTS
1.0 INTRODUCTION.................................................................................................................4
1.1 -Scope of Services............................................................................................................4
1.2 Project Description...........................................................................................................4
2.0 OBSERVATIONS.................................................................................................................4
2.1 Site Inspection.................................................................................................................4
2.2 Field Exploration ...................................... :....................................................................... 5
2.3 Laboratory Analysis.........................................................................................................5
2.4 Geomorphic Conditions....................................................................................................5
2.5 Hydrogeological Conditions..............................................................................................6
3.0 ENGINEERING EVALUATION AND RECOMMENDATIONS..............................................6
3.1
Foundation Recommendations........................................................................................6
3.2
Pile Foundation................................................................................................................6
3.3
Pile Installation.................................................................................................................7
3.4
Shallow Foundation ..............:..... ........8
3.5
General Site Preparation (Piles and Shallow Foundations)..............................................8
3.6
Design of Footings.........................................................................................................10
3.7
Ground Floor Slab..........................................................................................................10
3.8
Vibration Monitoring.......................................................................................................10
3.9
Excavation Conditions ...................................... .................................. I ...........................
10
4.0 REPORT LIMITATIONS..............................................................:......................................11
5.0 BASIS FOR RECOMMENDATIONS..; ............................................................................... 11
Appendix A - Vicinity Map
Appendix B - Test Location Plan
Appendix C - Notes Related to Borings
Appendix D - Record of Test Borings
Appendix E - Discussion of Soil Groups
GF�
Proposed Two -Story Residence Geotechnical Report
2001 Nettles Boulevard, St. Lucie County, FL August 29, 2013
GFA Project No. 13-1849.00 Page 4 of 12
1.0 INTRODUCTION
1.1 Scope of Services
The objective of our geotechnical services was to collect subsurface data for the subject project,
summarize the test results, and discuss any apparent site conditions that may have
geotechnical significance for building construction. The following scope of services are provided
within this report:
1. Prepare records of the soil boring logs depicting the subsurface soil conditions encountered
during our field exploration.
2. Conduct a review of each soil sample obtained during our field exploration for classification
and additional testing if necessary.
3. Analyze the existing soil conditions found during our exploration with respect to foundation
support for the proposed structure.
4. Provide recommendations with respect to foundation support of the structure, including
allowable soil -bearing capacity, bearing elevations, and foundation design parameters.
5. Provide criteria and site preparation procedures to prepare the site for the proposed
construction.
1.2 Project Description
Based on conversations with Ithe client, the project consists of constructing a two-story
residence. GFA was informed that piles or a shallow foundation is desired to be used for
support of the structure. We have not received any information regarding structural loads. For
the foundation recommendation, s presented in this report we assumed the maximum column
load will be 40 kips and the maximum wall loading will be 4 kips per linear foot. GFA estimates
the site is at or near final grade.)
The recommendations provided herein are based upon the above considerations. If the project
description has been revised,) please inform GFA International so that we may review our
recommendations with respect to any modifications.
2.0 OBSERVATIONS
2.1 Site Inspection
The project site was generally flat. The grade at the site was estimated to be even with the
adjacent road at the time of drilling. A one-story mobile home occupied the site. Residential
structures were adjacent to the property. The Intracoastal Waterway (Indian River) bordered the
south side of the property.
60
Proposed Two -Story Residence Geotechnical Report
2001 Nettles Boulevard, St. Lucie County, FL August 29, 2013
GFA Project No. 13-1849.00 Page 5 of 12
2.2 Field Exploration
A total of two (2) standard penetration test (SPT) borings to depths of approximately fifteen (15)
and forty (40) feet below ground surface (BGS) were completed for this study. The upper 4 feet
of the SPT borings were drilled with a hand auger in order to avoid damaging utilities. Hand
Cone Penetrometer (HCP) tests were conducted at one -foot intervals in the auger borings. The
HCP test, in conjunction with information about the soil type, is empirically correlated to the
relative density of subsurface soils. The locations of the borings performed are illustrated in
Appendix B: "Test Location Plan". The Standard Penetration Test (SPT) and HCP methods
were used as the investigative tools within the borings. SPT tests were performed in substantial
accordance with ASTM Procedure D-1586, "Penetration Test and Split -Barrel Sampling of Soils"
and the auger borings in substantial accordance with ASTM Procedure D-1452, "Practice for
Soil Investigation and Sampling by Auger Borings". The SPT test procedure consists of driving
a 1.4-inch I.D. split -tube sampler into the soil profile using a 140-pound hammer falling 30
inches. The number of blows per foot, for the second and third 6-inch increment, is an
indication of soil strength.
The soil samples recovered from the soil borings were visually classified and their stratification
is illustrated in Appendix D: 'Record of Test Borings". It should be noted that soil conditions
might vary between the strata interfaces, which are shown. The soil boring data reflect
information from a specific test location only. Site specific survey staking for the test locations
was not provided for our field exploration. The indicated depth and location of each test was
approximated based upon existing grade and estimated distances and relationships to obvious
landmarks. The boring depths were confined to the zone of soil likely to be stressed by the
proposed construction and knowledge -of vicinity soils.
2.3 Laboratory Analysis
Soil samples recovered from our field exploration were returned to our laboratory where they
were visually examined in general accordance with ASTM D-2488. Samples were evaluated to
obtain an accurate understanding of the soil properties and site geomorphic conditions. After a
thorough visual examination of the recovered site soils, no laboratory testing was deemed
necessary. Bag samples of the soil encountered during our field exploration will be held in our
laboratory for your inspection for 30 days and then discarded unless we are notified otherwise in
writing.
The recovered samples were not examined, either visually or analytically, for chemical
composition or environmental hazards. GFA would be pleased to perform these services for an
additional fee, if required.
2.4 Geomorphic Conditions
Boring logs derived from our field exploration are presented in Appendix D: 'Record of Test
Borings". The boring logs depict the observed soils in graphic detail. The Standard Penetration
Test borings indicate the penetration resistance, or N-values, and the auger borings the HCP
values logged, during the drilling and sampling activities. The classifications and descriptions
shown on the logs are generally based upon visual characterizations of the recovered soil
samples. All soil samples reviewed have been depicted and classified in general accordance
with the Unified Soil Classification System, modified as necessary to describe typical Florida
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Proposed Two -Story Residence Geotechnical Report
2001 Nettles Boulevard, St. Lucie County, FL August 29, 2013
GFA Project No. 13-1849.00 Page 6 of 12
conditions. See Appendix E: "Discussion of Soil Groups", for a detailed description of various
soil groups.
The subsurface soil conditions encountered at this site generally consist of medium dense sand
(SP) to a depth of 4 feet, loose to; medium dense sand (SP) from 4 to 13'/2 feet, medium dense
to dense sand (SP) from 13'/2 to 231/ feet, silt and clay (ML) from 23'/z to 28'/z feet, silty/clayey
sand (SM) from 28'/z to 33'/2, and then sand (SP) with trace cemented sand from 33'/2 to the
boring termination depths. Please refer to Appendix D - Record of Test Borings for a detailed
account of each boring.
2.5 Hydrogeological Conditions
On the dates of our field exploration, the groundwater table was encountered at depths of
approximately 4 and 4%2 feet below the existing ground surface. The groundwater table will
fluctuate seasonally depending upon local rainfall and other site specific and/or local influences
including the water levels in the nearby Intracoastal Waterway (Indian River) with tidal
influences. Brief ponding of stormwater may occur across the site after heavy rains.
No additional investigation was. included in our scope of work in relation to the wet seasonal
high groundwater table or any existing well fields in the vicinity. Well fields may influence water
table levels and cause significant fluctuations. if a more comprehensive water table analysis is
necessary, please contact our office for additional guidance.
3.0 ENGINEERING EVALUATION AND RECOMMENDATIONS
3.1 Foundation Recommen
A foundation system for any structure must be designed to resist bearing capacity failures, have
settlements that are tolerable, land resist the environmental forces that the foundation may be
subjected to over the life of the structure. The soil bearing capacity is the soil's ability to support
loads without plunging into the soil profile. Bearing capacity failures are analogous to shear
failures in structural design and are usually sudden and catastrophic.
The amount of settlement that a structure may tolerate is dependent on several factors
including: uniformity of settlement, time rate of settlement, structural dimensions and properties
of the materials. Generally, total or uniform settlement does not damage a structure but may
affect drainage and utility connections. These can generally tolerate movements of several
inches for building construction. In contrast, differential settlement affects a structure's frame
and is limited by the structural flexibility.
GFA was informed that a pile or shallow foundation are desired to be used for support of the
structure.
3.2 Pile Foundation
At this time, GFA recommends the deep foundation to consist of augered cast -in -place piles
(ACIP). ACIP pile installation procedures should be performed in accordance with the
guidelines presented in the latest edition of the Deep Foundations Institute's Augered Cast-In-
Proposed Two -Story Residence
2001 Nettles Boulevard, St. Lucie County, FL
GFA Project No. 13-1849.00
Geotechnical Report
August 29, 2013
Page 7 of 12
Place Pile Manual. The lateral capacity and pile top deflection were calculated using the
commercially available L-pile 4.0 software. A summary of pile capacities for a 14-inch diameter
ACIP piles is presented in the following table.
Pile Recommendations For All Pile Supported Structures
Maximum
Nominal
Pile Top
Recommended
Pile
Pile
Pile
Pile Lateral
Pile
Elevation
Pile Tip
Lengths
Compression
Tension
Capacity
Recommended
Diameter
NGVD
Elevation
(ft)*
Capacity
Ca aci
(Tons)'
Grout Strength
3 Tons
-
(Free Head)
8 Tons
14"
Unknown
Unknown
19
20 Tons
6 Tons
Fixed Head
5000 psi
3 Tons
(Free Head)
8 Tons
14"
Unknown
Unknown
32
30 Tons
9 Tons
Fixed Head
5000 psi
*Based on existing site grade.
**For calculated pile top deflection of % inches at ground surface/top of pile elevation.
The pile installation length is based on installing the piles at site grade (grade even with
the adjacent roadway) existing at time of drilling. If additional fill will be required to raise
the site to achieve final grade, the piles will be longer according to the depth of fill added.
GFA assumed that the piles will have a minimum of 1% steel reinforcement for the analyses.
Augercast piles should be reinforced over their entire length for tension capacity. The
reinforcement shall be as designed by the Structural Engineer.
If piles of lesser or greater capacities than those mentioned in the table above are required,
GFA would be pleased to provide further recommendations upon request.
The following additional notes are applicable to the pile design:
Structural stresses in the piles may impose a more severe limitation on the
design capacity; therefore, we recommend the allowable stresses be verified for
the selected pile section.
The pile reinforcement is sufficiently embedded in the pile cap so as to afford a
fixed end connection if required.
3.3 Pile Installation
Pile design and installation shall be in accordance with the applicable sections of the Florida
Building Code and other applicable federal, state and local requirements. In addition, piles
should be installed in accordance with the following:
1. Pile Length: The proposed 14-inch-diameter piles should be installed as determined by
the inspecting Geotechnical Engineer.
GV
Proposed Two -Story Residence Geotechnical Report
2001 Nettles Boulevard, St. Lucie County, FL August 29, 2013
GFA Project No. 13-1849.00 Page 8 of 12
2. Spacing - Piles installed in groups should be spaced at a center -to -center distance of not
less than 3 pile diameters.
3. Plan Location - The center of the top of any pile at cut-off should be displaced laterally
no more than 3 inches from the position shown on the plans. This applies to both single
piles and piles installed in groups.
4. Vertical Alignment - The I vertical alignment of the piling should not deviate from the
plumb by more than 1 /4 inch per foot of length.
5. Reinforcing Cage Positioning - The top of the reinforcing cages installed in the piling
should not be more than 6 inches above and no more than 3 inches below the positions
shown in the plans. The reinforcing cages should be positioned concentrically within the
grouted pile shaft. The grout cover over longitudinal reinforcing bars should not be less
than 3 inches. Reinforcing centralizers shall be placed at maximum spacing of 15 feet at
the lower portion of the pile and at 5 feet from the cage's top.
6. Adjacent Piles - A mi9limum time period of 12 hours should be specified for the
installation of piles located within 5 feet, center -to -center, of each other.
7. Grout Factor - The minimum acceptable grout factor (i.e. actual grout volume divided by
theoretical grout volume) should be 1.1.
3.4 Shallow Foundation
The subsurface soil conditions at the project site are generally favorable for the support of the
proposed structure on shallow foundations. An allowable bearing capacity of 2,500 psf may be
used for foundation design. Expected settlement of the structure. is 1 inch or less total and less
than '/z inch differential.
3.5 General Site Preparation! (Piles and Shallow Foundations)
GFA recommends the following compaction requirements for this project:
➢ Proof Roll ................... 95% of a Modified Proctor
➢ Building Pad Fill............................................................95% of a Modified Proctor
➢ 'Footings .................... I .................................................. 95% of a Modified Proctor
The compaction percentages presented above are based upon the maximum dry density as
determined by a "modified proctor" test (ASTM D-1557). All density tests should be
performed to a depth of 2 feet below stripped surface and 2 feet below bottom of
footings. All density tests should be performed using the nuclear method (ASTM D-2922), the
sand cone method (ASTM D-.1556), or Hand Cone Penetrometer (HCP) tests.
Our recommendations for preparation of the site are presented below. This approach to
improving and maintaining the site soils has been found to be successful on projects with similar
soil conditions.
Gfi�
Proposed Two -Story Residence Geotechnical Report
2001 Nettles Boulevard, St. Lucie County, FL August 29, 2013
GFA Project No. 13-1849.00 Page 9 of 12
1. Initial site preparation should consist of performing stripping (removing surface vegetation,
near surface roots, and other deleterious matter) and clearing operations. This should be
done within, and to a distance of five (5) feet beyond, the perimeter of the proposed building
footprint (including exterior isolated columns). Foundations and any below grade remains of
any structures that are within the footprint of the new construction should be removed, and
utility lines should be removed or properly abandoned so as to not affect structures. If the
demolished residence had a pile foundation, GFA must be notified as the recommendations
may change.
2. Following site stripping and prior the placement of any fill, areas of surficial sand (not
exposed limestone) should be compacted ("proof rolled") and tested. We recommend using
a steel drum vibratory roller with sufficient static weight and vibratory impact energy to
achieve the required compaction. Density tests should be performed on the proof rolled
surface at a frequency of not less than one test per 2,500 square feet, or a minimum of three
(3) tests, whichever is greater. Areas of exposed intact limestone shall be visually confirmed
by the project geotechnical engineer prior to fill placement, in lieu of proof rolling.
3. Fill material may then be placed in the building pad as required. The fill material should be
inorganic (classified as SP, SW, GP, GW, SP-SM, SW-SM, GW-GP, GP -GM) containing not
more than 5 percent (by weight) organic materials. Fill materials with silt/clay-size soil
fines in excess of 12% should not be used. Fill should be placed in lifts with a maximum
lift thickness not exceeding 12-inches. Each lift should be compacted and tested prior to the
placement of the next lift. Density tests should be performed within the fill at a frequency of
not less than one test per 2,500 square feet per lift in the building areas, or a minimum of
three (3) tests per lift, whichever is greater.
4. For any footings bearing on a limestone formation, the bottom of all footing excavation shall
be examined by the engineer / geologist or his representative to determine the condition of
the limestone. The limestone shall be probed for voids and loose pockets of sand. Such
areas shall be cleaned to depth of 3 times the greatest horizontal dimension and backfilled
with lean concrete.
5. For footings placed on structural fill or compacted native granular soils, the bottom of all
footings shall be tested for compaction and examined by the engineer / geologist or his
representative to determine if the soil is free of organic and/or deleterious material. Density
tests should be performed at a frequency of not less than one (1) density test per each
isolated column footing and one (1) test per each seventy five (75) lineal feet of wall
footings.
6. Upon completion of production pile installation and pile cap construction, the pile caps
should be backfilled in 6 to 8 inch thick lifts and compacted to at least 95% of the modified
Proctor maximum dry density (ASTM D 1557).
7. The contractor should take into account the final contours and grades as established by the
plan when executing his backfilling and compaction operations.
Using vibratory compaction equipment at this site may disturb adjacent structures. We
recommend that you monitor nearby structures before and during proof -compaction operations.
60
i
Proposed Two -Story Residence Geotechnical Report
2001 Nettles Boulevard, St. Lucie County, FL August 29, 2013
GFA Project No. 13-1849.00 Page 10 of 12
A representative of GFA International can monitor the vibration disturbance of adjacent
structures. A proposal for vibration monitoring during compaction operations can be supplied
upon request.
3.6 Design of Footings
Footings may be designed using an allowable soil bearing pressure of 2,500 psf. Shallow
foundations should be embedded, a minimum of 18 inches below final grade. This embedment
shall be measured from the lowest adjacent grade. Isolated column footings should be at least
24 inches in width and continuous strip footings should have a width of at least 18 inches
regardless of contact pressure.
Once site preparation has been performed in accordance with the recommendations described
in this report, the soil should readily support the -proposed structure resting on a shallow
foundation system. Settlements have been projected to be less than 1-inch total and '/z-inch
differential. All footings and columns should be structurally separated from the floor slab, as
they will be loaded differently and at different times, unless a monolithic mat foundation is
designed.
3.7 Ground Floor Slab
The ground floor slabs may be supported directly on the existing grade or on granular fill
following the foundation site preparation and fill placement procedures outlined in this report.
For purposes of design, a coefficient of subgrade modulus 150 pounds per cubic inch may be
used. The ground floor slab should be structurally separated from all walls and columns to
allow for differential vertical movement.
Water vapor is likely to rise thr I ugh the granular fill and condense beneath the base of the floor
slab. If moisture entry into the floor slab is not desirable, an impermeable membrane should be
installed at the slab bottom - sbgrade interface.
3.8 Vibration Monitoring I
The proposed construction will be within close proximity to residential structures and roadways
that maybe susceptible to damage from vibration generated at the site. We recommend that
during all aspects of construction, the bordering landmarks be monitored using a seismograph
to determine the extent of vibration absorption that these features will be subject to. The
seismograph used to monitor at this site should have the capability to measure ground velocities
along vertical, transverse, and longitudinal axes. The project structural engineer should
establish allowable ground velocities that the bordering facilities can safely withstand without
any damage.
3.9 Excavation Conditions
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 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
GF�
Proposed Two -Story Residence
2001 Nettles Boulevard, St. �ucie County, FL
GFA Project No. 13-1849.00
Geotechnical Report
August 29, 2013
Page 11 of 12
regulation that all excavations, whether they be utility trenches, basement excavations or footing
excavations, be installed in accordance with the 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.
4.0 REPORT LIMITATIONS
This consulting report has been prepared for the exclusive use of the current project owners and
other members of the design team for the Proposed Two -Story Residence located at 2001
Nettles Boulevard, St. Lucie County, Florida. This report has been prepared in accordance with
generally accepted local geotechnical engineering practices; no other warranty is expressed or
implied. The evaluation submitted in this report, is based in part upon the data collected during
a field exploration, however, the nature and extent of variations throughout the subsurface
profile may not become evident until the time of construction. If variations then appear evident,
it may be necessary to reevaluate information and professional opinions as provided in this
report. In the event changes are made in the nature, design, or locations of the proposed
structure, the evaluation and opinions contained in this report shall not be considered valid,
unless the changes are reviewed and conclusions modified or verified in writing by GFA
International.
Analysis of the foundation performance under hurricane conditions or other storm events,
including the effects of loss of soil support due to scour or other forces, is not within the scope of
this report, and the recommendations are valid only for normal conditions. Additional analysis
and options for foundation systems with scour conditions or other scenarios can be performed if
requested.
5.0 BASIS FOR RECOMMENDATIONS
The analysis and recommendations submitted in this report are based on the data obtained
from the tests performed at the locations indicated on the attached figure in Appendix B. This
report does not reflect any variations, which may occur between borings. While the borings are
representative of the subsurface conditions at their respective locations and for their vertical
reaches, local variations characteristic of the subsurface soils of the region are anticipated and
may be encountered. The delineation between soil types shown on the soil logs is approximate
and the description represents our interpretation of the subsurface conditions at the designated
boring locations on the particular date drilled.
GF�
Proposed Two -Story Residence Geotechnical Report
2001 Nettles Boulevard, St. Lucie County, FL August 29, 2013
GFA Project No. 13-1849.00 Page 12 of 12
Any third party reliance of our ge,otechnical report or parts thereof is strictly prohibited without
the expressed written consent of !GFA International. The applicable SPT methodology (ASTM
D-1586), CPT methodology (ASTM D-3441), and Auger Boring methodology (ASTM D-1452)
used in performing our borings' and sounding, and for determining penetration and cone
resistance is specific to the sampling tools utilized and does not reflect the ease or difficulty to
advance other tools or materials.)
GFi
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Appendix A - Vicinity Map
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Appendix B - Test Location Plan
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Appendix C - Notes Related to Borings
NOTES RELATED TO
RECORDS OF TEST BORING AND
GENERALIZED SUBSURFACE PROFILE
I. Groundwater level was encountered and recorded (if shown) following the completion of the soil test boring on
the date indicated. Fluctuations in groundwater levels are common; consult report text for a discussion.
2. The boring location was identified in the field by offsetting from existing reference marks and using a cloth tape
and survey wheel.
I
3. The borehole was backftlled to site grade following boring completion, and patched with asphalt cold patch mix
when pavement was encountered. i
4. The Record of Test Boring represents our interpretation of field conditions based on engineering examination of
the soil samples.
5. The Record of Test Boring is subject to the limitations, conclusions and recommendations presented in the Report
text.
6. "Field Test Data" shown on the Record of Test Boring indicated as 11/6 refers to the Standard Penetration Test
(SPT) and means 11 hammer blow s drove the sampler 6 inches. SPT uses a 140-pound hammer falling 30 inches.
7. The N-value from the SPT is the sum of the hammer blows required to drive the sampler the second and third 6-
inch increments. I
8. The soil/rock strata interfaces shown on the Records of Test Boring are approximate and may vary from those
shown. The soil/rock conditions shown on the Records of Test Boring refer to conditions at the specific location
tested; soil/rock conditions may ivary between test locations.
9. Relative density for sands/gravels and consistency for silts/clays are described as follows:
SPT
CPT
SANDS/GRAVELS
SPT
CPT
SILTS/CLAYS
BLOWS/FOOT
KG/CM2
RELATIVE DENSITY
BLOWS/FOOT
KG/CM-
CONSISTENCY
0-4
0-16
Very loose
0-1
0-3
Very soft
5-10
17-40
Loose
2-4
4-6
Soft
11-30
41-120
Medium Dense
5-8
7-12
Firm
31-50
121-200
Dense
9-15
13-25
Stiff
50+
over 200
'Very Dense
16-30
25-50
Verystiff
>30
>50
Hard
10. Grain size descriptions areas follows:
NAME
SIZE LIMITS
Boulder
12 Inches or more
Cobbles
3 to 12 Inches
Coarse Gravel
'/ to 3 Inches
Fine Gravel
No. 4 sieve to Y4 inch
Coarse Sand
No. 10 to No. 4 sieve
Medium Sand
No. 40 to No. 10 sieve
Fine Sand
No. 200 to No. 40 sieve
Fines
Smaller than No. 200 sieve
11. Definitions related to adjectives used in soil/rock descriptions:
PROPORTION
ADJECTIVE
APPROXIMATE ROOT DIAMETER
ADJECTIVE
<5%
Trace
Less than 1/32"
Fine roots
5% to 12%
Little
1/32" to %"
Small roots
12% to 30%
Some
%" to V
Medium roots
30% to 50%
And
Greater than V
Large roots
Organic Soils: Soils containing vegetable tissue in various stages of decomposition that has a fibrous to amorphous texture,
usually a dark brown to black color, and an organic odor.
Organic Content <25%: Slightly to Highly Organic; 25% to 75%: Muck; >75%: Peat
Appendix D - Record of Test Borings
GFA INTERNATIONAL
521 N.W. ENTERPRISE DRIVE, PORT ST. LUCIE, FLORIDA 34986
PHONE: (772) 924-3575 - FAX: (772) 924-3580
I STANDARD PENETRATION TEST BORING (ASTM D-1586)
Client: JWN Construction, Inc. Project No.:13-1849.00
Lab No.:
Project: Proposed Two -Story Residence, 2001 Nettles Boulevard Page: 1 of 2
St. Lucie County, Florida Date: 8/27/2013
Elevation: Existing Grade Drill Rig: Simco-24
Water Level: 4 feet after 0 hours Drilling Fluid commenced at depth of 10 feet Field Party: MUCH
Hand Auger with Hand Cone Pentrometer Test (HCP in ksf) performed in top 4 feet
TEST LOCATION: SPT - 1 N27.285460 W80.215290
Laboratory Tests
Depth
Blows/
N
Sample
Layer:
USCS
Description
Passing
Moisture
Organic
(feet)
6 in.
Value
No.
From/to
No. 200
Content
Content
0 - 6%2
SP
Light brown fine sand, some shell fragments
2
HCP=
80+
--
3
HCP=
50
I
---
2
I
4
HCP=
30
4
5
4
9
3
6
4
i
6'Y2 - 13Y2
SP
Gray fine sand, trace silt and clay,
1
7
1
_
2
4
some shell fragments
8
-1 -
---
i
---
Z
3
i
9
---6....
_.9 --
5
8
I
---
11
12
---
----
---
13%2 - 23%2
SP
Gray fine sand, trace silt and clay,
14
--10 ---------
16
trace shell fragments
is
--22 --
-38--
6
16
..............
18
----
--
--- 19
. 6..........
10
1
13
23
7
GFA INTERNATIONAL
521 N.W. ENTERPRISE DRIVE, PORT ST. LuCIE, FLORIDA 34986
PHONE: (772) 924-3575 - FAX: (772) 924-3580
STANDARD PENETRATION TEST BORING (ASTM D-1586)
Client: JWN Construction, Inc. Project No.:13-1849.00
Lab No.:
Project: Proposed Two -Story Residence, 2001 Nettles Boulevard Page: 2 of 2
St. Lucie County, Florida Date: 8/27/2013
Elevation: Existing Grade Drill Rig: Simco-24
Water Level: 4 feet after 0 hours Drilling Fluid commenced at depth of 10 feet Field Party: PM/CH
TEST LOCATION: SPT -1 N27.285460 W80.215290
Laboratory
Tests
Depth
Blows/
N
Sample
Layer:
USCS
Description
Passing
Moisture
Organic
(feet)
6 in.
Value
No.
From/to
No. 200
Content
Content
20
--------------
21
-------
------
22
----
---
23
..............
2
23%2 - 28'/2
ML
Dark gray silt and clay, trace fine sand
24
1•- _
_
trace shell fragments
1
2
8
25
... ......
--
26
---
.--
27
..............
28
----
---
2----------
28%2 - 33'/2
SM
Light gray fine sand, some silt and clay
29
_
3
8_
11
9
30
.
31
..............
32
----
---
33
-------
------
33'/2 - 38'/2
SP
Light gray fine sand, trace silt and clay,
34
..14.........
10
trace cemented sand
21
10
35
__11_
_
36
----
---
37
---•
---
38
..............
39
•9-
10
19
11
...Same
Boring terminated at 40 feet
GFA INTERNATIONAL
521 N.W. ENTERPRISE DRIVE, PORT ST. LUCIE, FLORIDA 34986
PHONE: (772) 924-3575 - FAX: (772) 924-3580
I STANDARD PENETRATION TEST BORING (ASTM D-1586)
Client: JWN Construction, Inc. Project No.:13-1849.00
Lab No.:
Project: Proposed Two -Story Residence, 2001 Nettles Boulevard Page: 1 of 1
St. Lucie County, Florida Date: 8/27/2013
Elevation: Existing Grade Drill Rig: Simeo-24
Water Level: 4 % feet after 0 hours Drilling Fluid commenced at depth of 10 feet Field Party: PM/CH
Hand Auger with Hand Cone PentrometeriTest (HCP in ksf) performed in top 4 feet
TEST LOCATION: SPT - 2 N27.28560° W80.21523°
Laboratory Tests
Depth
Blows/
N
Sample
Layer:
i
USCS
Description
Passing
Moisture
Organic
(feet)
6 in.
Value
No.
From/to
No. 200
Content
Content
0
SP
0 3%2
Brown fine sand, trace shell fragments
--•
HCP=
80+
1
1
2
HCP=
80+
I
I
----
HCP=
80+
3
2
4
HCP=
80+
SP
3'/2 - 9
Gray fine sand, trace silt and clay
6
trace shell fragments
15
23
3
16
7
- 4-
22
26
4
-15
___
8
-- --
'
9
--15 --
35
----
50
5
SP
1 9-15
Gray fine sand, some shell fragments
40
10
-------
------
12
..............
13
---•
---
14
-A ........
11
_
15
15
..............
26
6
Boring terminated at 15 feet
16
----
---
18
..............
19
..............
Appendix E - Discussion of Soil Groups
0
i
DISCUSSION OF SOIL GROUPS
COARSE GRAINED SOILS
GW and SW GROUPS. These groups comprise well -graded gravelly and sandy
soils having little or no plastic fines (less than percent passing the No. 200 sieve).
The presence of the fines must not noticeably change the strength characteristics
of the coarse -grained friction and must not interface with it's free -draining
characteristics.
GP and SP GROUPS. Poorly graded gravels and sands containing little of no
plastic fines (less than 5 percent passing the No. 200 sieve) are classed in GP
and SP groups. The materials may be called uniform gravels, uniform sands or
non -uniform mixtures ofl very coarse materials and very fine sand, with
intermediate sizes lacking (sometimes called skip -graded, gap graded or step -
graded). This last group often results from borrow pit excavation in which gravel
and sand layers are mixed.
GM and SM GROUPS. In general, the GM and SM groups comprise gravels or
sands with fines (more than 12 percent the No. 200 sieve) having low or no
plasticity. The plasticity index and liquid limit of soils in the group should plot
below the "A" line on the plasticity chart. The gradation of the material is not
considered significant and both well and poorly graded materials are included.
i
GC and SC GROUPS. In general, the GC and SC groups comprise gravelly or
sandy soils with fines (more than 12 percent passing the No, 200 sieve) which
have a fairly high plasticity. The liquid limit and plasticity index should plat above
the "A" line on the plasticity chart.
FINE GRAINED SOILS
MIL and MH GROUPS. In these groups, the symbol M has been used to
designate predominantly silty material. The symbols L and H represent low and
high liquid limits, respectively, and an arbitrary dividing line between the two set
at a liquid limit of 50. The soils in the MIL and MH groups are sandy silts, clayey
silts or inorganic silts with relatively low plasticity. Also included are loose type
soils and rock flours.
CL and CH GROUPS. In these groups the symbol C stands for clay, with L and
H denoting low or high liquid limits, with the dividing line again set at a liquid of
50. The soils are primarily organic clays. Low plasticity clays are classified as
CL and are usually lean clays, sandy clays or silty clays. The medium and high
plasticity clays are classified as CH. These include the fat clays, gumbo clays
and some volcanic clays.
Gf�
OL and OH GROUPS. The soil in the OL and OH groups are characterized by
the presence of organic odor or color, hence the symbol O. Organic silts and
clays are classified in these groups. The materials have a plasticity range that
corresponds with the ML and MH groups.
HIGHLY ORGANIC SOILS
The highly organic soils are usually very soft and compressible and have
undesirable construction characteristics. Particles of leaves, grasses, branches,
or other fibrous vegetable matter are common components of these soils. They
are not subdivided and are classified into one group with the symbol PT. Peat
humus and swamp soils with a highly organic texture are typical soils of the
group.