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FLORIDA'S LEADING ENGINEERING SOURCE
Report of Geotechnical Exploration
Roaf Residence
7683 Pelican Pointe Drive
Jensen Beach, Florida
August 21, 2019
GFA Project No. 19-4195.00
For: Oakmont Custom Homes, Inc.
00. Since 1988
Florida's
Source
Environmental • Geotechnical • Construction Materials Testing • Threshold and Special Inspections • Plan Review & Code Compliance
August 21, 2019
Mr. Bud Cordaro
Oakmont Custom Homes, Inc.
900 E. Ocean Blvd, Suite 340E
Stuart, Florida 34994
Subject: Report of Geotechnical Exploration
Roaf Residence
7683 Pelican Pointe Drive, Jensen Beach, Florida
GFA Project No. 19-4195.00
Dear Mr. Cordero:
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 No. 19-4195.00 dated June 19, 2019,
planned in conjunction with and authorized by Oakmont Custom Homes, Inc.
EXECUTIVE SUMMARY
The purpose of our subsurface exploration was to classify the nature of the subsurface soils and
general geomorphic conditions at the site and evaluate their impact upon the proposed
construction. This report contains the results of our subsurface exploration and our engineering
interpretations of these with respect to the project characteristics described to us, including
providing recommendations for foundation design and site preparation.
Per our recent conversations and email correspondence with you, GFA understands the project
consists of a new three-story residence located at 7683 Pelican Pointe Drive in Jensen Beach,
Florida. GFA was provided a Boundary & Topographic Survey prepared by Velcon Engineering
& Surveying, LLC dated June 12, 2019 showing the layout of the proposed building footprint on
the property.
Specific design loads have not been provided to GFA. For the foundation recommendations
presented in this report, we assumed a maximum wall loading of 10 kips per linear foot and a
maximum column load of 100 kips.
The recommendations provided herein are based upon the above considerations. If the stated
conditions are incorrect or if the project description is revised, please inform GFA so that we
may review our recommendations with respect to any modifications.
Three (3) standard penetration test (SPT) borings, advanced to an approximate depth of 45 feet
below the existing ground surface, were completed for this study. Most of the soils encountered
in the borings generally consisted of medium dense to dense fine sand (SP), fine sand with clay,
607 NW Commodity Cove • Port St. Lucie, Florida 34986 • (772) 924.3575 • (772) 9243580 (fax) • www.teamgfa.com
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Roaf Residence Geotechnical Exploration Report
7683 Pelican Pointe Drive, Jensen Beach, Florida August 21, 2019
GFA Project No. 19-4195.00 Page 2 of 12
(SP-SC), fine sand with silt (SP-SM), clayey fine sand (SC), and silty fine sand (SM) within the
upper 30 feet of the soil profile. These soils were underlain by very loose to dense layers of fine
sand (SP), fine sand with silt (SP-SM), silty fine sand (SM), and silty clayey fine sand (SC-SM)
to the boring termination depths. As an exception, very loose to loose fine sand and fine sand
with silt (SP, SP-SM) containing few organics were present within the upper 6 feet of boring B-3,
which was performed on the east side of the drainage swale. Please refer to Appendix D -
Record of Test Borings for a detailed account of each boring.
The relatively loose soils containing some organics encountered within the upper six (6)
feet of the soil profile in boring B-3 are not suitable to remain in place due to their
potential for contributing to excessive total and/or differential structure foundation
settlements. Therefore, GFA recommends that the six (6) feet of loose soils below the
proposed building footprint be excavated and replaced with controlled, compacted fill. The
loose soils should be removed from below the building footprint and to a distance of five (5) feet
beyond the building perimeter.
Prior to backfilling, the upper one (1) foot of soils along the excavation bottom should be
compacted to at least 95 percent of modified Proctor (ASTM D 1557) maximum dry density.
The over -excavation should then be backfilled to design grade using suitable portions of the
excavated soils and/or other available fill material. The fill should be placed in lifts having a
maximum thickness of 12-inches and compacted to at least 95 percent of modified Proctor
(ASTM D 1557) maximum dry density.
Following the removal and replacement of the loose soils and considering the results of our field
exploration program, the subsurface soil conditions at the site will be favorable for support of the
proposed residential structure upon shallow foundations. A maximum allowable soil bearing
pressure of 2,500 psf may be used for foundation design.
Within other portions of the site, the subgrade soils should be improved (densified) with
compaction from the stripped grade prior to constructing the building pad. Prior to placing fill to
achieve final grade, the upper 2 feet of soil below stripped grade should be compacted to a
minimum of 95 percent maximum dry density as determined by the modified Proctor test (ASTM
D 1557). Fill (including stem wall backfill) should be placed in 12-inch thick lifts and compacted
to achieve a minimum 95 percent modified Proctor maximum dry density. After completing the
footing excavations, the bearing subgrade to a depth of 2 feet should be compacted to not less
than 95 percent modified Proctor maximum dry density.
GFA
Roaf Residence Geotechnical Exploration Report
7683 Pelican Pointe Drive, Jensen Beach, Florida August 21, 2019
GFA Project No. 19-4195.00 Page 3 of 12
r
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.
Respectfully Submitted,
GFA International, Inc.
Florida Certificate of Authorization No. 4930
John)bDY'9i'0tah'n'Y
signed
Kent
KentDate., 2019.08.21
09.53.39-04'00'
John Kent, P.E.
Senior Project Engineer
Florida Registration No. 63218
This item has been digitally signed and sealed by John Kent, P.E. on the date
adjacent to the seal. Printed copies of this document are not considered signed
and sealed and the signature must be verified on any electronic copies.
Erik Soderstrom, E.I.
Geotechnical Department Manager
Distribution: Mr. Bud Cordaro — Oakmont Custom Homes, Inc.
1 pdf
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Roaf Residence Geotechnical Exploration Report
7683 Pelican Pointe Drive, Jensen Beach, Florida August 21, 2019
GFA Project No. 19-4195.00 Page 4 of 12
,
TABLE OF CONTENTS
1.0 INTRODUCTION................................................................................................................. 5
1.1 Scope of Services........................................................................................................... 5
1.2 Project Description.......................................................................................................... 5
3.0 ENGINEERING EVALUATION AND RECOMMENDATIONS ..............................................
8
3.1
General...........................................................................................................................8
3.2
Site Preparation..............................................................................................................
8
3.3
Vibration Monitoring........................................................................................................
9
3.4
Design of Footings.........................................................................................................10
3.5
Settlement Estimates.....................................................................................................10
3.6
Ground Floor Slabs........................................................................................................11
3.7
Site Excavations.............................................................................................................11
4.0 REPORT LIMITATIONS...............................................................................I.....................11
5.0 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
0
GfA
Roaf Residence Geotechnical Exploration Report
7683 Pelican Pointe Drive, Jensen Beach, Florida August 21, 2019
GFA Project No. 19-4195.00 Page 5 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 boring logs depicting the subsurface soil conditions encountered during our field
exploration.
2. Review the soil samples obtained during our field exploration for classification and additional
testing if necessary.
3. Evaluate 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
foundation type, maximum allowable soil bearing capacity, and bearing elevations.
5. Provide site preparation criteria for the proposed construction.
1.2 Project Description
Per our recent conversations and email correspondence with you, GFA understands the project
consists of a new three-story residence located at 7683 Pelican Pointe Drive in Jensen Beach,
Florida. GFA was provided a Boundary & Topographic Survey prepared by Velcon Engineering
& Surveying, LLC dated June 12, 2019 showing the layout of the proposed building footprint on
the property.
Specific design loads have not been provided to GFA. For the foundation recommendations
presented in this report, we assumed a maximum wall loading of 10 kips per linear foot and a
maximum column load of 100 kips.
The recommendations provided herein are based upon the above considerations. If the stated
conditions are incorrect or if the project description is revised, please inform GFA so that we
may review our recommendations with respect to any modifications.
2.0 OBSERVATIONS
2.1 Site Description
The project site was generally flat and consisted of a grass covered vacant lot at the time of our
field exploration. The site was bordered by other residential properties to the north, a fence, a
stormwater drainage swale (which is part of the property), and S Ocean Drive to the east,
vacant property to the south, and the Jensen Beach to Jupiter Inlet Aquatic Preserve to the
west.
GfH
Roaf Residence
7683 Pelican Pointe Drive, Jensen Beach, Florida
GFA Project No. 19-4195.00
2.2 Field Exploration
Geotechnical Exploration Report
August 21, 2019
Page 6 of 12
Three (3) standard penetration test (SPT) borings, advanced to an approximate depth of 45 feet
below the existing ground surface, were completed for this study. The locations of the borings
are illustrated in Appendix B - Test Location Plan.
The Standard Penetration Tests (SPT) were performed in general accordance with ASTM D
1566, 'Penetration Test and Split -Barrel Sampling of Soils." The SPT test procedure consists of
driving a 1.4-inch I.D. split -barrel 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 referred
to as the N-value. The N-value has been empirically correlated with various soil properties and
provides an indication of soil strength.
The upper 4 feet of boring B-3 was advanced using hand augering methods due to potential
utility line conflicts. The augered portion of this boring was performed in substantial accordance
with ASTM D 1452, "Practice for Soil Investigation and Sampling by Auger Borings." Hand Cone
Penetrometer (HCP) tests were conducted at one -foot depth intervals in the auger boring. The
HCP test, in conjunction with information about the soil type, is empirically correlated to the
relative density of subsurface soils
The soil samples recovered from the borings were visually classified and their stratification is
illustrated on the boring logs in Appendix D. Note that the soil boring data reflect information
from a specific test location only and the soil conditions may vary between the strata interfaces
indicated on the logs. The boring depths were established based upon our knowledge of vicinity
soils and confined to the zone of soil likely to be influenced by the planned construction.
2.3 Laboratory Testing
Soil samples recovered from our field exploration were returned to our laboratory where they
were visually classified by a geotechnical engineer in general accordance with the Unified Soil
Classification System (ASTM D 2487). Selected samples obtained from boring B-3 were tested
in the laboratory for moisture content (ASTM D 2216) and fines content, or percent dry weight
passing the U.S. No. 200 sieve (ASTM D 1140). The lab test results are summarized in Table
2.3.1 below and are also contained on the B-3 boring log.
Table 2.3.1 - Laboratory Test Results
Boring
No.
Sample
Depth
feet
Sample Description
Organic
Content
N
Moisture
Content
%
Fines
Content
%
B-3
3.5 - 4
Brown fine sand, few organics (SP)
6.3
54.5
4.6
B-3
4-6
Brown fine sand with silt (SP-SM)
-
57.9
6.2
B-3
33.5 - 35
Gray silty, clayey fine sand (SC-SM)
51.3
41.8
GFA
Roaf Residence Geotechnical Exploration Report
7683 Pelican Pointe Drive, Jensen Beach, Florida August 21, 2019
GFA Project No. 19-4195.00 Page 7 of 12
The recovered samples were not evaluated, either visually or analytically, for chemical
composition or environmental hazards. GFA will be pleased to perform these services for an
additional fee, if required. The soil samples will be retained in our laboratory for 30 days and
then discarded unless we are notified otherwise in writing.
2.4 Geomorphic Conditions
The geology of the site as mapped on the USDA Soil Survey website consists of Canaveral fine
sand, 0 to 5 percent slopes (10). 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
below ground surface and is not indicative of deeper soil conditions.
Boring logs resulting from our field exploration are presented in Appendix D - Record of Test
Borings. The boring logs contain the soil descriptions, the standard penetration test (SPT) N-
values, and the hand cone penetrometer (HCP) values logged during the drilling and sampling
activities. The soil classifications and descriptions shown on the logs are generally based upon
visual characterizations of the recovered samples using the Unified Soil Classification System.
See Appendix E - Discussion of Soil Groups, for a detailed description of various soil groups.
Most of the soils encountered in the borings generally consisted of medium dense to dense fine
sand (SP), fine sand with clay (SP-SC), fine sand with silt (SP-SM), clayey fine sand (SC), and
silty fine sand (SM) within the upper 30 feet of the soil profile. These soils were underlain by
very loose to dense layers of fine sand (SP), fine sand with silt (SP-SM), silty fine sand (SM),
and silty clayey fine sand (SC-SM) to the boring termination depths. As an exception, very
loose to loose fine sand and fine sand with silt (SP, SP-SM) containing few organics were
present within the upper 6 feet of boring B-3, which was performed on the east side of the
drainage swale.
2.5 Hydrogeological Conditions
On the dates of our field exploration (August 2, 6, and 7, 2019), the groundwater table was
encountered at depths of approximately 3.3 to 5.5 feet below ground surface at the boring
locations. Note that the groundwater table will fluctuate seasonally depending upon local rainfall
and other site specific and/or local factors, including tidal influences from the adjacent Jensen
Beach to Jupiter Inlet Aquatic Preserve. Brief ponding of stormwater may occur across the site
after heavy or extended rainfall events.
No additional evaluation 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.
GFf�
Roaf Residence Geotechnical Exploration Report
7683 Pelican Pointe Drive, Jensen Beach, Florida August 21, 2019
GFA Project No. 19-4195.00 Page 8 of 12
3.0 ENGINEERING EVALUATION AND RECOMMENDATIONS
3.1 General
Our geotechnical engineering evaluation of the site and subsurface conditions at the property,
with respect to the planned construction, and our recommendations for site preparation and
foundation support, are based upon (1) our site observations, (2) the field data obtained, and (3)
our understanding of the project information and structural conditions as presented in this
report. If the stated conditions are incorrect, or if the project description is revised, please
inform GFA so that we may review our recommendations with respect to any modifications.
We note that the applicability of geotechnical.recommendations is very dependent upon project
characteristics, specifically (1) improvement locations, (2) grade alterations, (3) and actual
applied structural loads. For that reason, GFA must be provided with and review the preliminary
and final site and grading plans, and structural design loads to validate all recommendations
provided in this report. Without performing this review, our recommendations should not be
relied upon for final design or construction of any site improvements.
3.2 Site Preparation
GFA recommends the following compaction requirements for this project:
➢ Proof Roll...............................................................95 percent of modified Proctor
➢ Building Pad Fill......................................................95 percent of modified Proctor
➢ Footings.................................................................95 percent of modified Proctor
The compaction percentages presented above are based upon the maximum dry density as
determined by the modified Proctor test (ASTM D 1557). All density tests should be
performed to a depth of 2 feet below stripped surface and the bottom of foundation
excavations. Density testing should be performed using either the nuclear method (ASTM D
6938) or the sand cone method (ASTM D 1556). Hand Cone Penetrometer (HCP) tests can
also be performed to evaluate compaction.
Our recommendations for preparation of the site for use of shallow foundation systems are
presented below. This approach to improving and maintaining site soils has been found to be
successful on projects having similar soil conditions.
Initial site preparation should consist of removing vegetation, topsoil, near surface roots, and
other miscellaneous debris within and to a distance of 5 feet beyond of the planned
construction limits. Foundations and the below grade remains of former structures within the
footprint of the new construction should also be removed. Similarly, utility lines within the
limits of the proposed construction should be removed or properly abandoned so that they
will not adversely impact overlying structures.
Roaf Residence Geotechnical Exploration Report
7683 Pelican Pointe Drive, Jensen Beach, Florida August 21, 2019
GFA Project No. 19-4195.00 Page 9 of 12
2. Relatively loose soils containing some organics were encountered within the upper
six (6) feet of the soil profile in boring B-3 which was performed on the eastern side of
the fence near the drainage swale. These soils are unsuitable to remain in place due
to their potential for contributing to excessive total and/or differential structure
foundation settlements. Therefore, GFA recommends that the six (6) feet of loose soils
below the proposed building footprint be excavated and replaced with controlled, compacted
fill. The loose soils should be removed from below the building footprint and to a distance of
five (5) feet beyond the building perimeter.
Prior to backfilling, the upper one (1) foot of soils along the excavation bottom should be
compacted to at least 95 percent of modified Proctor (ASTM D 1557) maximum dry density.
The over -excavation should then be backfilled to design grade using suitable portions of the
excavated soils and/or other available fill material. The fill should be placed in lifts having a
maximum thickness of 12-inches and compacted to at least 95 percent of modified Proctor
(ASTM D 1557) maximum dry density.
3. Within other portions of the property following site stripping and prior to the placement of fill,
areas of surficial sand 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.
4. Fill material may then be placed for the building pad and general site grading, as required.
The fill 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. GFA does not
recommend using fill materials having slit/clay-size soil fines contents exceeding 12
percent. Fill should be placed in lifts having a maximum thickness of 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 building areas, or a minimum of three (3) tests per lift, whichever is greater.
5. For foundations placed on structural fill or compacted native granular soils, the bearing
subgrade should be tested for compaction and observed by an engineer or geologist or
his/her 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
footing.
6. The contractor should consider the final grading contours contained in the project plans
when executing backfilling and compaction operations.
3.3 Vibration Monitoring
Using vibratory compaction equipment at this site may disturb adjacent residences and other
nearby structures. We recommend that these structures be monitored by GFA both before and
during compaction operations. A proposal for providing, vibration monitoring services during
earthwork construction will be provided upon request.
GfP
Roaf Residence Geotechnical Exploration Report
7663 Pelican Pointe Drive, Jensen Beach, Florida August 21, 2019
GFA Project No. 19-4195.00 Page 10 of 12
. .
3.4 Design of Footings
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.
Considering the results of our field exploration program, the subsurface soil conditions at the
project site are generally favorable for support of the proposed structure on shallow foundations.
A maximum allowable soil bearing pressure of 2,500 psf may be used for foundation design.
This design value is contingent upon performing the initial site preparation in the area of
boring B-3 requiring the over -excavation of loose soils followed by replacement' with
controlled, compacted fill.
Shallow foundations should be embedded a minimum of 12 inches below final grade measured
from the lowest adjacent grade. Isolated column footings should be at least 24 inches in width.
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 presented
in this report, the soils should readily support the proposed structure bearing upon a properly
designed and constructed shallow foundation system. Footings and columns should be
structurally separated from the ground floor slab, as they will be loaded differently and at
different times, unless a monolithic slab foundation is designed.
3.6 Settlement Estimates
Post construction settlements of the structure will be influenced by several interrelated factors,
including (1) subsurface soil stratification and the strength/compressibility characteristics, (2)
footing size, bearing level, applied loads, and resulting bearing pressure beneath the footings,
and (3) the site preparation and earthwork construction techniques used by the contractor. Our
settlement estimates for the proposed construction are based on the use of the site preparation
and earthwork construction methods as recommended in this report. Any deviation from these
recommendations could result in an increase in the estimated post -construction settlements of
the proposed construction.
We expect the majority of settlement to occur in an elastic manner and fairly rapidly during
construction. Using the recommended maximum bearing pressure, the assumed maximum
structural loads, and the field test data that we have correlated geotechnical strength and
compressibility characteristics of the subsurface soils, we estimate that total settlements of the
structure could be on the order of one (1) inch or less.
Differential settlements result from differences in applied bearing pressures and variations in the
compressibility characteristics of the subsurface soils. Because of the general uniformity of the
subsurface conditions and the recommended site preparation and earthwork construction
methods presented in this report, we anticipate that differential settlements of the structure
should be within tolerable magnitudes (0.5 inch or less).
GF�
Roaf Residence Geotechnical Exploration Report
7683 Pelican Pointe Drive, Jensen Beach, Florida August 21, 2019
GFA Project No. 19-4195.00 Page 11 of 12
3.6 Ground Floor Slabs
The ground floor slab may be constructed upon either existing grade or granular fill following
completion of the foundation site preparation and fill placement procedures outlined in this
report. We recommend that a modulus of subgrade reaction (k) of 150 pounds per cubic inch
(pci) be considered during design. The floor slab should be structurally separated from walls
and columns to allow for differential vertical movement, unless a monolithic slab foundation is
.designed.
Excessive moisture vapor transmission through foundation slabs can result in damage to floor
coverings as well as cause other deleterious affects. An appropriate moisture vapor barrier
should be placed beneath the slab to reduce moisture vapor from entering the structure through
the slab. The barrier should be installed in general accordance with applicable ASTM
procedures including sealing around pipe penetrations and at the foundation edges.
3.7 Site Excavations
In Federal Register, Volume 54, No. 209 (October 1989), the United States Department of
Labor, Occupational Safety and Health Administration (OSHA) amended its "Construction
Standards for Excavations, 29 CFR, part 1926, Subpart P." This document was issued to better
ensure the safety of workers 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.
4.0 REPORT LIMITATIONS
This consulting report has been prepared for the exclusive use of Oakmont Custom Homes, Inc.
and the project design team for the proposed residence located at 7683 Pelican Pointe Drive in
Jensen Beach, 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 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 location of the proposed structure, the evaluation
(FP-
Roaf Residence Geotechnical Exploration Report
7683 Pelican Pointe Drive, Jensen Beach, Florida August 21, 2019
GFA Project No. 19-4195.00 Page 12 of 12
and opinions contained in this report should not be considered valid unless the changes are
reviewed, and conclusions modified or verified in writing by GFA.
GFA should be provided the opportunity to review the final foundation plans and specifications
to determine if GFA's recommendations have been properly interpreted, communicated, and
implemented. If GFA is not afforded the opportunity to participate in construction related
aspects of foundation installation as recommended in this report or any report addendum, GFA
cannot accept responsibility for the interpretation of our recommendations made in this report or
in a report addendum for foundation performance.
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 Test Location Plan 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 boring logs is
approximate and the descriptions represent our interpretation of the subsurface conditions at
the designated boring locations on the specific dates drilled.
Any third -party reliance of this geotechnical report or parts thereof is strictly prohibited without
the expressed written consent of GFA International, Inc. The applicable SPT methodology
(ASTM D 1586) and Auger Boring methodology (ASTM D 1452) used in performing our borings,
and for determining penetration resistance, is specific to the sampling tools utilized and does not
reflect the ease or difficulty to advance other tools or materials.
GfA
Appendix A - Vicinity Map
N
Appendix B - Test Location Plan
GfR
Test Location Plan: 7683 Pelican Pointe Drive, Jensen Beach, FL
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NOTVALID v21NOVTlHE OpiOLJAL GTCNATUPE AND MISED
SEAL OPAFLORIDALTCENSED ANYEYOP AND ALVPE0.
I}'EE%PECTEDV5EOFTIIESNVEYANDMAPESRESIDENfl.14
AL D15TANCES AND FLEVATICA9 SNONNARETN ACLTRD
WITH lryF U1VIlE0 ]TATESSTANDARp WLJi FftT.
ALLDIREC7IONALAIEASWEMENTS5HO1WNARE W THE
FORIAAT OF DEOREEs, MINJaIFSANDSEQIMS:
aGFT DIRLOpNOFOpK 2M5,1PAo�BIZCCCOpDS aF
ST LUCIF LOUNIY. fIIINIM.
NATTEDLOTCONTANS209ASQUAIZFEE7,
PUBLIC VlAlE0. d5EWERAYAiLARLE I�
BCJI:NDARYd RIPOLRAPHICALStipI£Y FIE10 DAIFi RG/05/19.
CERTIFIED TO: ROAD
Approximate Standard Penetration Test Boring Locations
Appendix C - Notes Related to Borings
GfH
NOTES RELATED TO BORING RECORDS AND
GENERALIZED SUBSURFACE PROFILES
1. Groundwater levels (if encountered) were recorded either during or following the boring completion on
the date indicated. Fluctuations in groundwater levels are common - see the report text for a discussion.
2. The boring locations were identified in the field by estimated distances and offsets from existing reference
marks and/or other site landmarks.
3. The completed boreholes were backfilled to adjacent site grade using drilling spoils and patched with
asphalt cold mix in pavement areas.
4. The Log of Boring records represent our interpretation of soil conditions based on visual classification of
the soil samples recovered from the borings.
5. The Log of Boring records are subject to the limitations, conclusions, and recommendations presented in
the report text.
6. The Standard Penetration Test (SPT) N-values contained on the Log of Boring records refer to the total
blow counts of a 140-pound drop hammer falling 30 inches required to drive a split -barrel sampler a total
distance of 12 inches into soil strata at specific depth intervals.
7. The Hand Cone Penetrometer (HCP) values contained on Log of Boring records and the Cone
Penetration Test (CPT) values contained on the Cone Penetration Sounding logs refer to the cane tip
resistance recorded when pushing the cone tip into the soil strata at specific depth intervals.
8. The soil and/or rock strata interfaces shown on the Log of Boring records are approximate and may vary
from those shown on the logs. The soil and/or rock descriptions shown on the Log of Boring records refer
to conditions at the specific location tested. Soil/rock conditions may vary between test locations.
9. Relative density for coarse -grained soils (sands/gravels) and consistency for fine-grained soils (silts/clays)
are described as follows:
Coarse Grained Soils (Sands and Gravels)
Fine Grained Soils (Silts and Clays)
SPT
N-Value
HCP Value
(kg/cm2)
CPT Value
(tsf)
Relative
Density
SPT
N-Value
HCP Value
(kglcm2)
CPT Value
(tsf)
Consistency
0-4
0-16
0-20
Very Loose
-20
0-3
Very Soft
5-10
17-36
21-40
Loose
3-4
21-35
4-6
Soft
1130
37-116
41-120
Med. Dense
5-8
>35
7-12
Finn
31-50
117-196
121-200
Dense
9-15
13-25
Stiff
>50
> 196
>200
Very Dense
16-30
26-50
very Stiff
>30
>50
Hard
10. Grain size descriptions areas follows:
Description
Particle Size Limits
Boulder
Greater than 12 inches
Cobble
3 to 12 inches
Coarse Gravel
3/4 to 3 inches
Fine Gravel
No. 4 sieve to 314 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 SiIUCla)
Smaller than No. 200 sieve
11. Definitions for modifiers used in soil/rock descriptions:
Proportion
Modifier
Approximate Root Diameter
Modifier
<5%
Trace
Less than /32"
Fine roots
5%to12%
Little
/3i'to'/4°
Small roots
12% to 30%
Some
Va to 1"
Medium roots
30% to 50%
And
Greater than V
Large roots
Organic Soils: Soils containing vegetative tissue in various stages of decomposition having a fibrous to amorphous
texture. Usually having a dark brown to black color and an organic odor.
Organic Content Modifiers: <25%: Slightly to Highly Organic; 25%to 75%: Muck; >75%: Peat
GfP
Appendix D - Record of Test Borings
GfA
GFA International, Inc. LOG OF BORING B-1
Nt. Commodity Cove
PAGE 1 OF 2
Port St. Lucie, Florida 34986
Part
1r
\�/ 1 L772) 924 - 3575
P
�RNRT��
CLIENT Oakmont Custom Homes Inc. PROJECT NAME Rost Residence
PROJECT NUMBER 19-4195.00 PROJECT LOCATION 7683 Pelican Pointe Drive, Jensen Beach, FL
DRILLING CONTRACTOR GFA International Inc. HOLE DEPTH 45 It HOLE DIAMETER 3 in
DRILLER PM/ES DATE STARTED 8/2/19 COMPLETED 8/2119
DRILLRIG CME-45 GROUNDWATER LEVEL: SAT TIME OF DRILLING 5.40ft
METHOD SPT LATITUDE LONGITUDE
NOTE: HAMMER TYPE
w
♦ SPT N VALUE
Z
0�
U_
Q- w
rn
w
Lu
:3
U
20 40 60 80
PL MC LL
F—�—�
��
o_ c
¢ c
=C9
°' O
MATERIAL DESCRIPTION
m
3z
OJ O
?
a
y w
Zz
w
ww �""
��
<J
Q.
m0
U
>
z
Oz
�Z
20 40 60 80
❑ FINES CONTENT (%) ❑
w
c0
z
n oo
0 0
20 40 60 80
Broom fine sand with silt (SPSM)
2
..
1
6
6
11
5
4
,:..;
2
6
11
....
._.............. _.............
4
3
5
Q
3
4
e
4
..
6
11
Gray fine sand with clay (SPSC)
2
9.0
5
4
18 10
14
Gray clayey fine sand With shell (SC)
10
13.5
Gray silty fine sand, trace shell (SM)
6
15
18
3
3
15
:. :::•.
7
s
18
20—
(Continued Next Page)
GFA International, Inc. LOG OF BORING B-1
Nt. Commodity Cove
Port St. Lucie, Florida 34986 PAGE 2 OF 2
Port
_ (772) 924 - 3575
P
NNPT9�
CLIENT Oakmont Custom Homes, Inc. PROJECT NAME Road Residence
PROJECT NUMBER 19-4195.00 PROJECT LOCATION 7683 Pelican Pointe Drive, Jensen Beach, FL
w
A SPT N VALUE
0
U
o:
y
w
°
U °
20 40 60 80
PL MC LL
x
(L
¢
x
a 0
w
3 �
=1
¢
z
w
o`"
c
�`�
��
MATERIAL DESCRIPTION
��
o_x
��
>
w
0
I • i
20 40 60 80
w
O
z
030
U
z
�z
� 0
of
0 0
❑ FINES CONTENT (%) ❑
20 40 60 80
Gray silty fine sand, trace shell (SM) (continued)
23.5
Gray fine sand, trace shell (SP)
8
e
16
25
128.5
..............
Gray silty, clayey fine sand (SCSM)
a........;
......:.......: ......:.......
y
a
6
30
. .
............. j...... :....... j......
0
10 L, 0WOH
u
35
1138.5
'
Gray fine sand Wth silt (SPSM)
'
112042
is
40
43.5
Gray silty, dayey fine sand with shell (SC-SM)
,.
..._ .. ;.......:......:.......:.....
12
5
8
45.0
Bottom of borehole at 45.0 feel.
GFA International, Inc. LOG OF BORING B-2
Nt. Commodity Cove
G
Port St. Lucie, Florida 34986 PAGE 1 OF 2
Port
(772) 924 - 3575
�RNIit10�'
CLIENT Oakmont Custom Homes, Inc. PROJECT NAME Rcaf Residence
PROJECT NUMBER 19-4195.00 PROJECT LOCATION 7683 Pelican Pointe Drive, Jensen Beach, FL
DRILLING CONTRACTOR GFA International Inc. HOLE DEPTH 45It HOLE DIAMETER 3 in
DRILLER JB/LB DATESTARTED 8/6/19 COMPLETED 8/6/19
DRILLRIG CME-45 GROUNDWATER LEVEL: SAT TIME OF DRILLING 5.50ft
METHOD SPT LATITUDE LONGITUDE
NOTE: HAMMERTYPE
w
♦ SPT N VALUE
=
0
U
w
F
?
of F
U
20 40 60 80
PL MC LL
0�
~
ac
~
¢x
a o
MATERIAL DESCRIPTION
g
a
N w
(9w
ui ..
0
>"
¢�
a�
z
030
0
>
z
Lnz
o:Z
20 40 60 80
❑ FINES CONTENT (%) El
w
0
m
0
O 0
20 40 60 80
opsoil (2')
Brown fine sand with silt (SPSM)
3
.
s
71
17
..... .......... .....:..............
3
10
.:
.....
..
2
16
72
29
.......:.. .........._..............
12
?. ..
.
4.0
.......:...... L.....:..............
Gray fine sand with silt, trace organics (SPSM)
10
5
3
is
29
jZ
11
;.':.
6.0
Gray fine sand with silt (SPSM)
a
:....
.•'
4
10
1z
22
_..... ............ ...............
9
12
16
17
33
is
10
6
zo
39
15
18.5
•
Gray fine sand with silt and shell (SPSM)
'
7
ie
30
20
(Continued Next Page)
'a
U'
0
a
0
z
GFA International, Inc. LOG OF BORING B-2
Nt. Commodity Cove
Port St. Lucie, Florida 34986 PAGE 2 OF 2
Port
1f
.1�. q72) 924 - 3575
'ERNPT0�4
CLIENT Oakmont Custom Homes, Ina PROJECT NAME Road Residence
PROJECT NUMBER 19-4195.00 PROJECT LOCATION 7683 Pelican Pointe Drive, Jensen Beach, FL
w
♦ SPT N VALUE
=
ZO
v
w
F
?
F
0----
20 40 60 80
PL MC LL
I • i
do
~ "�
~ E
<�
o_ 00
MATERIAL DESCRIPTION
=
¢
w
w
w �"
Wv
-�
o_
m O
U
>
Z
U)
z
o: z
20 40 60 80
El FINES CONTENT (%)❑
Co
NZ
2O
OO
20 40 60 80
Gray fine sand with silt and shell (SPSM) (continued)
(•.:.
23.5
........: .............:...... .......
:'•"':'
..:..:
Gray fine sand with shell (SP)
'
....:
13
.......:......:...... _......:.......
8
1a
3
23
25
28.5
Gray silty fine sand with shell (SM)
0
...... v.......:......:.......
9
o
WOH
30
33.5
......_.......
Gray silty fine sand ISM)
10
0
u
WOH
35
ti
ILI31
is
40
:
12
1
u
IWO
4 5. 0
Bottom of borehole at 45.0 teeL
GFA International, Inc. LOG OF BORING B-3
A607 NW Commodity Cove
Port St. Lucie, Florida 34986 PAGE 1 OF 2
V72) 924 - 3575
CLIENT Oakmont Custom Homes, Inc. PROJECT NAME Roaf Residence
PROJECT NUMBER 194195.00 PROJECT LOCATION 7683 Pelican Pointe Drive, Jensen Beach, FL
DRILLING CONTRACTOR GFA Intemational Inc. HOLE DEPTH 45 it HOLE DIAMETER 3 in
DRILLER JB/LB DATESTARTED 817119 COMPLETED 8f7/19
DRILLRIG CME-45 GROUNDWATER LEVEL: -VAT TIME OF DRILLING 3.30 ft
METHOD SPT LATITUDE LONGITUDE
NOTE: HAMMER TYPE
w
♦ SPT N VALUE A
p
U
o:
rn
w
°
U °
20 40 60 80
PL MC LL
• ii
o_x
~ "-'
v
¢c
v
=
o
MATERIAL DESCRIPTION
w
� M
��
� z
O
¢
7~
y w
z�
C¢7 w
W
O
>
>
�
a O
m 0
O
>
z
z0
rr
20 40 60 80
❑ FINES CONTENT (%) ❑
W
C7
z
O p
20 40 60 80
Gray fine sand vrith silt, little shell (SPSM)
so
2.0
Gray fine sand, trace shell (SP)
.. :::.
40 Brown fine sand, few organics, trace silt (SP)
oisture=54.Fines =4.6%,Organic =6.3%)
Brown fine sand with silt (SP-SM)
1
5
;.
(Moisture = 57.9%, Fines = 6.2%)
3
0
u
1
:.:.
..:
6.0
Gray fine sand, trace shell (SP)
4
:.:.
..:.:
4
8
13
21
12
5
5
20
38
15
10
?>
13.5
Gray fine sand (SP)
JL6
12
22
15
::.
18.5
Gray fine sand, trace shell and silt (SP)
[201TTI
7
2,80,
41
(Continued Next Page)
GFA International, Inc. LOG OF BORING B_3
Nt. Commodity Cove
Gf�
Port St. Lucie, Florida 34986 PAGE 2 OF 2
Pori
., q72) 924 - 3575
RNPr�N
CLIENT Oakmont Custom Homes, Inc. PROJECT NAME Roaf Residence
PROJECT NUMBER 19-4195.00 PROJECT LOCATION 7683 Pelican Pointe Drive, Jensen Beach, FL
w
♦ SPT N VALUE
ZO
U
rn
w
U
20 40 60 80
PL MC LL
1 • i
H .-.
o- c
F=,-,
<r
x0
a 0
MATERIAL DESCRIPTION
m
3z
of 0
¢
�z
N w
Zz
w
wv
0
<�
a0
m0
U
Z
Oz
�z
20 40 60 80
❑ FINES CONTENT ("/o)❑
wv
C7
<Z
200
00
20 40 60 80
Gray fine sand, trace shell and silt (SP) (continued)
:'.
23.5
... .,
Gray silty fine sand with shell (SM)
7
...... :......::......_...............
8
a
7
25
28.5
.. .:
Gray fine sand, trace shell (SP)
18
L9_
22
42
2
30
.:
33.5
.'
Gray silty, clayey fine sand(SCSM)
.'
1
................. ..;.......;......
(Moisture = 51.3%, Fines = 41.6%)
Ll
1
2
35
38.5
................... ................
.:
Gray fine sand with shell (SP)
11
iu
22
40
43.5
Gray silty fine sand (SM)
L12
a
16
.13
45.0
45 Bottom of borehole at 45.0 feet.
Appendix E - Discussion of Soil Groups
GfP
DISCUSSION OF SOIL GROUPS
COARSE GRAINED SOILS
General. A soil is classified as coarse -grained if more than 50 percent of a representative
sample of the material is retained on the No. 200 sieve.
GW and SW Groups. These groups comprise well -graded gravelly and sandy soils
containing little or no plastic fines (less than 5 percent passing the No. 200 sieve). The low
fines content does not noticeably change the shear strength characteristics of these soils
and does not interfere with their free -draining characteristics.
GP and SP Groups. Poorly graded gravels and sands containing little or no plastic fines
(less than 5 percent passing the No. 200 sieve) are in the GP and SP groups. The
materials can 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 passing the No. 200 sieve) having little or no plasticity. The
plasticity index and liquid limit of soils in these groups 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
containing fines (more than 12 percent passing the No, 200 sieve) having plasticity
characteristics. The plasticity index and liquid limit of soils in these groups plot above the
"A" line on the plasticity chart.
FINE GRAINED SOILS
General. A soil is classified as fine-grained if more than 50 percent of a representative
sample of the material passes the No. 200 sieve.
ML and MH Groups. These groups comprise inorganic silts (ML) and elastic silts (MH)
having either low (L) or high (H) liquid limits, respectively. ML soils have a liquid limit of
less than 50 while MH soils have a liquid limit of 50 and greater. Silts and elastic silts can
also contain varying amounts of sand and gravel. Also included in this group are loess
sediments and rock flours.
CL and CH Groups. These groups comprise low plasticity (lean) clays (CL) and medium
to high plasticity (fat) clays (CH) having either low (L) or high (H) liquid limits, respectively.
CL soils have a liquid limit of less than 50 while CH soils have a liquid limit of 50 and
greater. The low plasticity clays can also be sandy clays or silty clays. The moderate to
high plasticity clays can also be sandy clays and include some volcanic clays.
GFA
OL and OH Groups. These groups comprise organic silts and clays. The soils are
characterized by the presence of organic odor and/or dark color. The OL and OH soils
are differentiated by determining and comparing their liquid limit values before and after
oven drying representative soil samples.
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
vegetative 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.
GFA