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GFA INTERNATIONAL
FLORIDA'S LEADING ENGINEERING SOURCE
Report of Geotechnical Exploration
Proposed Harbour Ridge Lifestyle Center
13400 Gilson Road
St. Lucie County, Florida SCANNED
BY
St. Lucie County
January 7, 2015
GFA Project No.: 14-2920.00
For: Harbour Ridge Property Owners Association, Inc.
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Florida's Leading Engineering Source
Environmental • Geotechnical • Construction Materials Testing • Threshold and Special Inspections • Plan Review& Code Compliance
January 7, 2015
Harbour Ridge Homeowners Association, Inc.
Attention: Peter Cavitt
12600 Harbour Ridge Blvd.
Palm City, Florida 34990
Site: Proposed Harbour Ridge Lifestyle Center
13400 Gilson Road
St. Lucie County, Florida
GFA Project # 14-2920.00
Dear Mr. Cavitt:
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 (14-2920.00) dated November 21,
2014, 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 a site plan prepared by Masteller & Moler, Inc. dated 6/23/2014 (reproduced in
Appendix B - Test Location Plan) and conversations with the client, the project consists of
constructing a 1-story clubhouse, swimming pool, frrlairitenance building,. -future sales center,
new hard courts, and new pavement areas. Several existing structures will be demolished and
removed including an existing clubhouse and several tennis courts. 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 70 kips and the maximum wall loading will
be 4 kips per linear foot. GFA estimates that up to 1 foot of fill will be required to bring the
foundation pad to design 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 four (4) standard penetration test (SPT) borings to depths of approximately fifteen (15)
and twenty (20) feet, and six (6) Auger Borings (AB) to approximately ten (10) feet, below
ground surface (BGS) were completed for this study.
521 NW Enterprise Drive • Port St. Lucie, Florida 34986 • (772) 924-3575 • (772) 924.3580 (fax) • www.teamgfa.com
OFFICES THROUGHOUT FLORIDA
Proposed Harbour Ridge Li,�atyle Center Geotechnical Report
St. Lucie County, Florida January 7, 2015
GFA Project No. 14-2920.00 Page 2 of 12
The subsurface soil conditions encountered at this site generally consist of medium dense sand
(SP) to a depth of 5'/2 feet, and then medium dense sand (SP) with slightly silty/clayey to silty
layers (SP-SM,SM) to the boring termination depths. Please refer to Appendix D Record of
Test Borings for a detailed account of each boring and sounding.
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.
The subgrade soils should be improved with compaction from the stripped grade prior to
constructing the foundation pads. The top 2 feet below stripped grade should be compacted to
a minimum of density prior to placing fill to achieve final grade. Fill (including stemwall
backfill) should be placed in 12-inch lifts and compacted to achieve a minimum 95% density.
After excavation for footings, the subgrade to a depth of 2 feet below bottom of footings should
be compacted to achieve a minimum 95% density.
We appreciate the opportunity to be of service to you on this project and look forward to a
continued association. Please do not hesitate to contact us if you have any questions or
comments, or if we may further assist you as your plans proceed.
Number 4930
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(I FA
Proposed Harbour Ridge L;,w lyle Center Geotechnical Report
St. Lucie County, Florida January 7, 2015
GFA Project No. 14-2920.00 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....................................................................................................6
2.5
Hydrogeological Conditions .................. :...........................................................................
6
3.0 ENGINEERING EVALUATION AND RECOMMENDATIONS..............................................6
3.1
General............................................................................................................................6
3.2
Site Preparation...............................................................................................................7
3.3
Design of Footings...........................................................................................................8
3.4
Ground Floor Slabs..........................................................................................................8
3.5
Pool Construction Recommendations..............................................................................9
3.6
Excavation Conditions......................................................................................................9
4.0 PARKING AND ROADWAY CONSTRUCTION RECOMMENDATIONS ............................10
4.1 General Components.....................................................................................................10
4.2 Effects of Water.............................................................................................................10
4.3 Construction Traffic........................................................................................................10
4.4 P9vement Site Preparation............................................................................................11
5.0 REPORT LIMITATIONS.....................................................................................................12
6.0 BASIS FOR RECOMMENDATIONS..................................................................................12
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
Proposed Harbour Ridge Ln'tyle Center Geotechnical Report
St. Lucie County, Florida January 7, 2015
GFA Project No. 14-2920.00 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 is provided
within this report:
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 a site plan prepared by Masteller & Moler, Inc. dated 6/23/2014 (reproduced in
Appendix B - Test Location Plan) and conversations with the client, the project consists of
constructing a 1-story clubhouse, swimming pool, maintenance building, future sales center,
new hard courts, and new pavement areas. Several existing structures will be demolished and
removed including an existing clubhouse and several tennis courts. 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 70 kips and the maximum wall loading will
be 4 kips per linear foot. GFA estimates that up to 1 foot of fill will be required to bring the
foundation pad to design 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 site was an existing operating clubhouse complex with
several 1-story buildings, tennis courts, and paved parking areas. The grade at the site was
estimated to be 2 feet above the adjacent road at the time of drilling.
(I FA
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Proposed Harbour Ridge L"' lyle Center Geotechnical Report
St. Lucie County, Florida January 7, 2015
GFA Project No. 14-2920.00 Page 5 of 12
2.2 Field Exploration
A total of four (4) standard penetration test (SPT) borings to depths of approximately fifteen (15)
and twenty (20) feet, and six (6) Auger Borings (AB) to approximately ten (10) 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
The geology of the site as mapped on the USDA Soil Survey website consists of Jonathan
sand, 0 to 5 percent slopes (19) and Salerno and Punta sands (39). These are sandy soils
and organic soils are not indicated. It should be noted that the Soil Survey generally extends
to a maximum depth of 80 inches (approximately 6% feet) below ground surface and is not
indicative of deeper soil conditions.
C,FA
Proposed Harbour Ridge "tyle Center
St. Lucie County, Florida
GFA Project No. 14-2920.00
Geotechnical Report
January 7, 2015
Page 6 of 12
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
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 5%2 feet, and then medium dense sand (SP) with slightly silty/clayey to silty
layers (SP-SM,SM) to the boring termination depths. Please refer to Appendix D - Record of
Test Borings for a detailed account of each boring and sounding.
2.5 Hydrogeological Conditions
On the dates of our field exploration, the groundwater table was encountered at depths ranging
from approximately 4 to 7%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.
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 General
A foundation system for any structure must be designed to resist bearing capacity failures, have
settlements that are tolerable, and 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.
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 %2 inch differential.
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Proposed Harbour Ridge L3>�sigle Center Geotechnical Report
St. Lucie County, Florida January 7, 2015
GFA Project No. 14-2920.00 Page 7 of 12
3.2 Site Preparation
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........................................................................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 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 for use of shallow foundation systems are
presented below. This approach to improving and maintaining the site soils has been found to
be successful on projects with similar soil conditions.
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.
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.
6FA
Proposed Harbour Ridge L �yle Center
St. Lucie County, Florida
GFA Project No. 14-2920.00
Geotechnical Report
January 7, 2015
Page 8 of 12
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. If compaction cannot be attained due to persistent wetness or the water table near
the bottom of the footing excavation, or due to silty/clayey soil 'pumping' during compaction,
GFA recommends undercutting below bottom of footing and replacement with No. 57 stone,
or rock/sand fill for subgrade that cannot be compacted per recommendations (upper 2
feet). The rock/sand fill should be compacted and tamped into the excavation and inspected
and verified by a representative from GFA, and tested with hand cone penetrometers, probe
rods, or density tests.
6. 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.
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.
3.3 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 12 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 16 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 %-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.
3.4 Ground Floor Slabs
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.
Excessive moisture vapor transmission through floor slabs -oh -grade can result in damage to
floor coverings as well as cause other deleterious affects. An appropriate moisture vapor
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Proposed Harbour Ridge L.�;yle Center Geotechnical Report
St Lucie County, Florida January 7, 2015
GFA Project No. 14-2920.00 Page 9 of 12
retarder should be placed beneath the floor slab to reduce moisture vapor from entering the
building through the slab. The retarder should be installed in general accordance with
applicable ASTM procedures including sealing around pipe penetrations and at the edges of
foundations.
3.5 Pool Construction Recommendations
The pool can be ground supported. During the pool excavation, soils that are suitable for use as
fill should be stockpiled separately. Most of the sand soils observed from the borings will provide
good fill material. Soils with high silt or organic "contents should not be used for structural fill
under the pool deck (or beneath any other structure).
The excavated surface (bottom of the pool) should be compacted so that the upper 1 foot of the
subgrade soil achieve a density of at least 95% of the modified Proctor maximum dry density
(ASTM D 1557).
The backfill around the pool should be placed in 6 to 8 inch lifts and compacted to 95% of the
modified Proctor maximum dry density (ASTM D 1557). The backfill soil should be "clean" sand
with less than 5% fines (% of dry weight passing a U.S. No. 200 sieve). Higher fine contents can
be used but more construction control is necessary.
If the water table is above the bottom of the proposed pool, dewatering will be necessary during
the construction. Furthermore, the pool structure should be anchored to resist hydraulic uplift
when it is empty or hydrostatic pressure relief valves should be installed in the bottom of the
pool.
3.6 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
regulation that all excavations, whether they be utility trenches, basement, excavations or footing
excavations, be constructed in accordance with the OSHA guidelines.
The contractor is solely responsible for designing and constructing stable, temporary
excavations and should shore, slope, or bench the sides of any excavations deeper than 4 feet
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.
GFA is providing this information solely as a service to our client. GFA is not assuming
responsibility for construction site safety or the contractor's activities; such responsibility is not
being implied and should not be inferred.
6FA
Proposed Harbour Ridge L'''Iv�&iyle Center Geotechnical Report
St. Lucie County, Florida January 7, 2015
GFA Project No. 14-2920.00 Page 10 of 12
4.0 PARKING AND ROADWAY CONSTRUCTION RECOMMENDATIONS
4.1 General Components
Because projected traffic loadings are commonly unavailable at the time of project conception,
GFA has generalized our pavement recommendations. GFA recommends a flexible pavement
section consisting of three -layers for this project. Flexible pavements combine the strength and
durability of several layers to produce an appropriate and cost-effective combination of available
materials. These pavements may be placed directly on top of the compacted subgrade or
embankment fill.
GFA recommends that light duty roadways and parking areas have at least 12 inches of
stabilized subbase (LBR 40 minimum), 6 inches of base course, and 1.5 inches of surface
course. Light duty pavement sections are usually used for auto parking areas with an average
gross weight of 4,000 pounds contributed by cars and light pickup trucks. These materials
should yield a structural number of approximately 2.7 if properly constructed.
GFA recommends a heavy duty pavement section consisting of at least 12 inches of stabilized
subgrade (LBR 40 minimum), 8 inches of base course, and 2 inches of surface course. Heavy-
duty pavement sections are usually used for shopping/office center and commercial driveways.
These materials should yield a structural number of approximately 3.3, if properly constructed.
Rigid pavement sections (concrete) may be constructed directly over the granular site
leveling/subgrade fill soils. For design, we recommend using a modulus of subgrade reaction of
150 pci for the well compacted granular fill. GFA recommends rigid pavements for zones
traversed by heavy trucks as well as dumpster pads.
4.2 Effects of Water
Many roadways and parking areas have prematurely deteriorated due to intrusion of the wet
seasonal high groundwater table or surface runoff mitigation.
GFA recommends the roadways and parking areas be constructed with a minimum separation
of 1'/z feet between the wet seasonal high groundwater table and the base course, independent
of the type of base material used. In addition, the parking areas should be constructed with full -
depth curb sections. Using extruded curb sections, which lie directly on top of the final surface
course or eliminating the curbing entirely, may allow migration of runoff and/or irrigation water to
migrate between the base and surface course. This migration can result in separation of the
surface course from the base course causing a rippling effect, which result in an increase
deterioration of the pavement.
4.3 Construction Traffic
Incomplete pavement sections or areas of pavement designed for light duty traffic will not
perform satisfactory under construction traffic loadings. GFA recommends all construction
traffic (i.e. construction equipment, etc.) be re-routed away from these areas or the pavement
sections be designed to support these loading conditions.
6FA
Proposed Harbour Ridge L,esyle Center Geotechnical Report
St. Lucie County, Florida January 7, 2015
GFA Project No. 14-2920.00 Page 11 of 12
4.4 Pavement Site Preparation
Upon review of the site soil data, GFA's recommendations of site preparation for pavements are
noted below. This approach to improving and maintaining the site soils has been found to be
successful with similar soil conditions.
1. Initial site preparation should consist of performing dewatering operations if necessary prior
to any earthwork.
2. The proposed construction limits should be cleared, stripped and grubbed of all construction
debris, trees, and vegetation and associated root systems to a depth of their vertical reach.
This should be done within and to a distance of 5 feet beyond the road perimeter.
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.
3. Prior to any fill operations, the existing ground surface should be compacted. GFA
recommends a medium weight roller be used to prepare the site for the proposed pavement
section. Upon completion of the proof -rolling, density tests should be performed at a
frequency of one test per 5,000 square feet, or at a minimum of two test locations,
whichever is greater, to confirm a minimum compaction compliance of 98% of modified
proctor maximum density (AASHTO T-180).
4. Place fill material, as required. The fill material should be inorganic (classified as SP/GW)
containing not more than 5% (by weight) organic materials. Fill materials with silt -size
soil fines in excess of 10% should not be used, this includes cyclone sand material.
Place fill in maximum 12-inch lifts and compact each lift to a minimum density of 98% of the
Modified Proctor maximum dry density (AASHTO T-180) with a roller as mentioned
previously.
5. .Perform compliance tests within the fill at a frequency of not less than one test per 5,000
square feet per lift in the pavement areas, or at a minimum of two test locations, whichever
is greater.
6. The appropriate pavement section should be constructed in accordance to specification
presented earlier in this report.
7. The contractor shall take into account the final contours and grades as established by the
paving and drainage plan when executing any backfilling and / or compaction operations.
Using vibratory compaction equipment at this site may disturb adjacent structures. GFA
recommends that you monitor nearby structures before and during proof -compaction
operations. If disturbance is noted, halt vibratory compaction operations and inform GFA
immediately. GFA will review the compaction procedures and evaluate if the compactive effort
resulted in a satisfactory subgrade, complying with design specifications.
6FA
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Proposed Harbour Ridge L;,eyle Center Geotechnical Report
St Lucie County, Florida January 7, 2015
GFA Project No. 14-2920.00 Page 12 of 12
5.0 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 Harbour Ridge Lifestyle Center located at
13400 Gilson Road, 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.
6.0 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.
Any third party reliance of our geotechnical 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.
(I FA
Appendix A - Vicinity Map
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Appendix B - Test Location Plan
6FH
,`!!!,.. Test Location Plan: Proposed Harbour Ridge Lifestyle Center, 13400 Gilson Road, St. Lucie County, FL
a�n
\ J y�� i �4
\ r�✓� P .✓ , �� :I yb �1� ° :�+n—S-•,v �'`t�. _ SPT- ✓ tv I
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\ \ \ ... �^•J v ;�., �� *�G � � ,.� SPT_2,.
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NEEDTOWORKOUT
STAIRS vs SIDEWALK
N ELEVATION OF PATIO ' CJ.•� _______ ;'tr
AROUND PRO SHOP
✓
r
Approximate Standard Penetration Test (SPT) Boring & Auger Boring (AB) Locations
Appendix C - Notes Related to Borings
GfP
NOTES RELATED TO
RECORDS OF TEST BORING AND
GENERALIZED SUBSURFACE PROFILE
1. 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.
3. The borehole was backfilled to site grade following boring completion, and patched with asphalt cold patch mix
when pavement was encountered.
4. The Record of Test Boring represents our interpretation of field conditions based on engineering examination of
the soil samples.
S. 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 blows 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.
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 vary 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/CM
RELATIVE DENSITY
BLOWS/FOOT
KG/CM4
CONSISTENCY
04
0-16
Very loose
0-1
0-3
Very soft
5-10
1740
Loose
24
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
Very stiff
>30
>50
Hard
10. Grain size descriptions are as 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 '/. 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
I 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 Y."
Small roots
12%to 30%
Some
W, to F.
Medium roots
30% to 50%
And
Greater than 1"
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
GfP
Appendix D - Record of Test Borings
GFP
GFA INTERNATIONAL
521 N.W. ENTERPRISE DRIVE, PORT ST. Luc1E, FLORmA 34986
PHONE: (772) 924-3575 - FAx: (772) 924-3580
STANDARD PENETRATION TEST BORING (ASTM D-1586)
Client: Harbour Ridge Property Owners Association Inc. Project No.:14-2920.00
Lab No.:
Project: Proposed Harbour Ridge Lifestyle Center Page: 1 of 1
13400 Gilson Rd, St. Lucie County, Florida Date: 12/22/2014
Elevation: Existing Grade Drill Rig: Simco-24
Water Level: 5 feet after 0 hours Drilling Fluid commenced at depth of 8 feet Field Party: PW/WN/GL
Hand Auger with Hand Cone Pentrometer Test (HCP in ksf) performed in top 4 feet
TEST LOCATION: SPT - 1 N27.2199I W80.29487°
Laboratory Tests
Depth
Blows/
N
Sample
Layer:
USCS
Description
Passing
Moisture
Organic
(feet)
6 in.
Value
No.
From/to
No.200
Content
Content
0
Asphalt (2 3/8 inches)
HCP=
80+
Base (6.1/8 inches)
1
1-2
SP
Gray fine sand
HCP
80+
1
2 - 5%2
SP
Light gray fine sand
HCP=
80+
4
HCP=
_ 80+
2
5
5
7
12
8
3
5%2 - 8
SP-SM,SM
Dark brown organically stained fine sand,
6
14
little/some silt
--- 7------
15
29
4
8
••16--
5
......
8- 13'/2
SP-SM
Light gray fine sand, little silt and clay
7
9
--- •7--•
--1--•
4-
8.........
5
10
.'
11
-------
------
12
.............
13
-------
------
5
13%2 - 15
SP
Light gray fine sand
14
6
---15
7
13
6
Boring Terminated at 15 feet
16
-------
------
17
-------
------
18
-------
------
19
-------
------
,_,)
GFA INTERNATIONAL
521 N.W. ENTERPRISE DRIVE, PORT ST. Luci4 FLORIDA 34986
PnoNE:(772)924-3575 - FAx:(7721924-3580
I STANDARD PENETRATION TEST BORING (ASTM D-1586) I
Client: Harbour Ridge Property Owners Association Inc. Project No.:14-2920.00
Lab No.:
Project: Proposed Harbour Ridge Lifestyle Center Page: 1 of 1
13400 Gilson Rd, St. Lucie County, Florida Date: 12/22/2014
Elevation: Existing Grade Drill Rig: Simco-24
Water Level: 5 feet after 0 hours Drilling Fluid commenced at depth of 10 feet Field Party: PW/WN/GL
Hand Auger with Hand Cone Pentrometer Test (HCP in ksi) performed in top 4 feet
TEST LOCATION: SPT - 2 N27.219407° W80.295408°
Laboratory Tests
Depth
Blows/
N
Sample
Layer:
DSCS
Description
Passing
Moisture
Organic
(feet)
6in.
Value
No.
From/to
No. 200
Content
Content
0
Asphalt (3 inches)
1
HCP=
80+
Base (5 3/4 inches)
1-2
SP
Gray fine sand
2
HCP=
80+
1
2 - 5%
SP
Light gray fine sand
4
HCP=
80+
2
6
5
6
7
13
8
3
5%2 - 9
SP-SM,SM
Dark brown organically stained fine sand,
6
5
little/some silt
7
6
8
14
11
4
8
--
---
�..
8
13
21
9 - 13'/z
SP-SM,SM
Light gray fine sand, little/some clay
13........
5
10
11
------
------
12.
------
------
13
------
------
13'/2 - 20
SP
Light gray fine sand
t4
..A
8
15
__!I--
19
6
16
------
------
17
............
18
............
--- 19
"4........
5
9
7
Boring Terminated at 20 feet
GFA INTERNATIONAL
521 N.W. ENTERPRISE DRIVE, PORT ST. LocnE, FLORIDA 34986
PHONE: (772) 924-3575 - FAx: (772) 924-3580
STANDARD PENETRATION TEST BORING (ASTM D-1586)
Client: Harbour Ridge Property Owners Association Inc.
Project: Proposed Harbour Ridge Lifestyle Center
13400 Gilson Rd, St. Lucie County, Florida
Elevation: Existing Grade
Project No.:14-2920.00
Lab No.:
Page:
1 of 1
Date:
12/22/2014
Drill Rig:
Simco-24
Water Level:4 3/4 feet after 0 hours Drilling Fluid commenced at depth of 10 feet Field Party: PW/WN/GL
Hand Auger with Hand Cone Pentrometer Test (HCP in lest) performed in top 4 feet
TEST LOCATION: SPT - 3 N27.219660 W80.295100
Laboratory Tests
Depth
Blows/
N
Sample
Layer:
USCS
Description
Passing
Moisture
(feet)
6in.
,Value
No.
From/to
Na.
ContentCaotenc
0
0-2
SP
Light brown fine sand
2
HCP=
1
2-7
SP
Light gray fine sand
-- --
-80+-
----
--• 3
HCP=
80+
4
HCP=
80+
2
4
5
5
............
7
12
6
$•.
••••••
3
6
12
7 - 9Y2
SM
Dark brown organically stained fine sand,
12
24
13
4
some silt
8
--
7
-
8
9
••13 •
21
11
5
9'% - 13%2
SP-SM,SM
Brown fine sand, little/some silt and clw.
10
.
11
------
------
12
------
------
13
............
5
13'/2 - 20
SP
Light gray fine sand
14
8
--15-1..
16
6
16
-•---•
-•----
17
------
------
18
-----
......
--- 19
_.4 ..
......
4
5
9
7
Boling Terminated at 20 feet
GFA INTERNATIONAL
521 N.W. ENTERPRISE DRIVE, PORT ST.LucM FLORIDA34986
PHONE:(772)924-3575 - FAx: (772) 924-3580
STANDARD PENETRATION TEST BORING (ASTM D-1586)
Client: Harbour Ridge Property Owners Association Inc. Project No.:14-2920.00
Lab No.:
Project: Proposed Harbour Ridge Lifestyle Center Page: 1 of 1
13400 Gilson Rd, St. Lucie County, Florida Date: 12/22/2014
Elevation: Existing Grade Drill Rig: Simco-24
Water Level: 4 feet after 0 hours Drilling Fluid commenced at depth of 8 feet Field Party: PW/WN/GL
Hand Auger with Hand Cone Pentrometer Test (HCP in kst) performed in top 4 feet
TEST LOCATION: SPT - 4 N27.21970° W80.29519°
Laboratory Tests
Depth
Blows/
N
Sample
Layer:,
I1$CS
Description
P
Passing
Moisture
Organic
(feet)
6in.
Value
No.
From/to
No. 200
Content
Content
0
Asphalt (3 1/2 inches)
1
HCP=
............
80+
Base (4 inches)
1-2
SP
Gray fine sand
HCP=
80+
1
2
2-5
SP
Light gray fine sand
HCP.
80+
4
HCP=
80+
2
10
5
10__
- -
_
5 - 7'/2
SP-SM,SM
Dark brown organically stained fine sand,
20
30
12
3
little/some silt
6
-- _.
8
7
_ 8
10
18
20
4
7%2 - 13%2
SP-SM
Gray fine sand, little silt and clay
8
6
--•
8
9
••12•
•20•
5 .
10
..!0- .
......
11
------
.-----
12
------
------
13
------
.-----
8
13 %2 - 20
SP
Light gray fine sand
14
-- ........
_•
8
15
_ 13
21
6
16
------
------
17
............
3
4
-
3
7
7
Boring Terminated at 20 feet
sincelloe J'j_ A
Florida's Leading Engineering Source
AUGER BORING LOGS WITH HAND CONE PENETROMETER (HCP) TESTS
Client: Harbour Ridge Property Owners Association Inc.
Project: Proposed Harbour Ridge Lifestyle Center
13400 Gilson Road, St. Lucie County, FL
Elevation: Existing Grade
Project No:
Lab No:
Test Date:
Technician:
14-2920.00
12/23/2014
PM/WN/GL
TEST LOCATION: AB —1 N27.21950 W80.294630
HCP
Depth (feet)
Description (color, texture, consistency, remarks)
Depth
Reading
0 — 6'/
Light brown fine sand SP
1
80+
6Y: — 10
Brown fine sand, some silt and clay SM,SC)
2
50
3
20
4
10
5
40
6
50
7
50
8
30
9
30
10
40
Water table at 7% feet below ground surface
TEST LOCATION: AB — 2 N27.21914° W80.29459°
HCP
Depth (feet)
Description (color, texture, consistency, remarks)
Depth
Reading
0-5
Light gray fine sand SP
1
80+
5 — 7%
Brown fine sand SP
2
80+
7'/z — 10
Brown fine sand, some silt and clay SM,SC)
3
80+
4
60
5
50
6
80+
7
80+
8
80+
9
80+
10
80+
Water table at 7'% feet below ground surface
Y
-,--r -- — r---
Since 1988 L
Florida's leading Engineering Source
AUGER BORING LOGS WITH HAND CONE PENETROMETER (HCP) TESTS I
Client: Harbour Ridge Property Owners Association Inc.
Project: Proposed Harbour Ridge Lifestyle Center
13400 Gilson Road, St. Lucie County, FL
Elevation: Existing Grade
Project No:
Lab No:
Test Date:
Technician:
14-2920.00
12/23/2014
PMNVN/GL
TEST LOCATION: AB — 3 N27.21908° W80.29508°
HCP
Depth (feet)
Description (color, texture, consistency, remarks)
Depth
Reading
0-3
Dark brown fine sand, little silt SP-SM
1
40
3-5
Grey fine sand SP
2
80+
5-8
Light gray fine sand SP
3
80+
8 —10
Light gray fine sand, little silt and clay SP-SM,SP-SC
4
80+
5
80+
6
80+
7
80+
8
80+
9
80+
10
Water table at 5'/ feet below ground surface
TEST LOCATION: AB — 4 N27.21973° W80.29660°
HCP
Depth (feet)
Description (color, texture, consistency, remarks)
Depth
Reading
0-2
Brown fine sand SP
1
80+
2-5
Light gray fine sand SP
2
80+
5-7
Dark brown organically stained fine sand, little/some silt SP-SM,SM
3
70+
7 — 8'/:
Brown fine sand SP
4
80+
8'/ —10
Brown fine sand, trace clay SP
5
80+
6
80+
7
80+
8
80+
9
80+
10
80+
Water table at 4% feet below ground surface
00- since]988 L
Florida's Leading Engineering Source
AUGER BORING LOGS WITH HAND CONE PENETROMETER (HCP) TESTS
Client: Harbour Ridge Property Owners Association Inc. Project No: 14-2920.00
Project: Proposed Harbour Ridge Lifestyle Center Lab No:
13400 Gilson Road, St. Lucie County, FL Test Date: 12/23/2014
Elevation: Existing Grade Technician: PM/WN/GL
TEST LOCATION: AB — 5 N27.21962° W80.29647°
HCP
Depth (feet)
Description (color, texture, consistency, remarks)
Depth
Reading
0 — 2
Grayish brown fine sand, trace silt SP
1
70
2 — 8'/:
Light gray fine sand SP
2
80+
8'/ —10
Brown fine sand SP
3
60
4
80+
5
80+
6
80+
7
60
8
80+
9
80+
10
80+
Water table at 4314feet below ground surface
TEST LOCATION: AB — 6
HCP
Depth (feet)
Description (color, texture, consistency, remarks)
Depth
Reading
0-1
Grayish brown fine sand SP
1
80+
1-5
Light Grey fine sand SP
2
80+
5-6
Dark brown organically stained fine sand, little/some silt SP-SM,SM
3
80+
6-9
Light brown fine sand, trace clay SP
4
40
9 —10
Light gray fine sand, little silt and clay SP-SM,SP-SC
5
80+
6
80+
7
80+
8
80+
9
80+
10
80+
r
Appendix E - Discussion of Soil Groups
GF
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 of 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.
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
ML 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 ML 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.
GfP
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.
GfH