HomeMy WebLinkAboutENGINEERINGRECEIVED
APR 112018
ST. Lucie County, Permitting
SUBSURFACE SOIL EXPLORATION AND
GEOTECHNICAL ENGINEERING EVALUATION
SEDONA RESIDENTIAL DEVELOPMENT - PHASE 1
3182-3192 MORNINGDEw LANE (BUILDING T-15)
ST. LUCIE COUNTY, FLORIDA
AACE FILE No.17-249
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ANDERSEN ANDRE CONSULTING ENGINEERS, INC.
834 SW Swan Avenue
Port St. Lucie, Florida 34983
Ph:772-807-9191 Fx:772-807-9192
www.aaceinc.com
TABLE OF CONTENTS
SUBSURFACE SOIL EXPLORATION AND
GEOTECHNICAL ENGINEERING EVALUATION
SEDONA RESIDENTIAL DEVELOPMENT - PHASE 1
3182-3192 MORNINGDEw LANE (BUILDING T-15)
ST. LUCIE COUNTY, FLORIDA
AACE FILE No.17-249
PAGE #
1.0 INTRODUCTION............................................................... 1
2.0 SITE INFORMATION AND PROJECT UNDERSTANDING ..................................... 1
3.0 FIELD EXPLORATION PROGRAM...................................................2
4.0 OBSERVED SUBSURFACE CONDITIONS...............................................2
4.1 General Soil Con ditions.............................................2
4.2 Measured Groundwater Level......................................3
5.0 LIMITED LABORATORY TESTING PROGRAM...........................................3
6.0 GEOTECHNICAL ENGINEERING EVALUATION...........................................3
6.1 General..........................................................3
6.2 Site Preparation Recommendations .................................. 3
6.3 Foundation and Slab Design........................................4
7.0 QUALITY ASSURANCE...........................................................5
8.0 CLOSURE....................................................................5
• Sheet No. 1 • Site Vicinity Maps
• Sheet No. 2 • Boring Location Plan and Soil Boring Profiles
• Appendix I • USDA Soil Survey Information
• Appendix II • General Notes (Soil Borings, Sampling and Testing Methods)
• Appendix 11 • AACE Project Limitations and Conditions
ANDERSEN ANDRE CONSULTING ENGINEERS, INC.
WWW.AACEINC.COM
ANDERSEN ANDRE CONSULTING ENGINEERS, INC
Geotechnical Engineering
Construction Materials Testing
Environmental Consulting
Edwards Landing, LLC
2324 South Congress Avenue, Suite 2E
West Palm Beach, FL 33406
Attention: Mr. Gregg Wexler
SUBSURFACE SOIL EXPLORATION AND
GEOTECHNICAL ENGINEERING EVALUATION
SEDONA RESIDENTIAL DEVELOPMENT - PHASE 1
3182-3192 MORNINGDEw LANE (BUILDING T-15)
ST. LUCIE COUNTY, FLORIDA
1.0 INTRODUCTION
AACE File No. 17-249
March 1, 2018
In accordance with your authorization, Andersen Andre Consulting Engineers, Inc. (AACE) has
completed a subsurface exploration and geotechnical engineering analyses for the above
referenced project. The purpose of performing this exploration was to explore shallow soil types
and groundwater levels as they relate to the proposed single -story residential building
construction, and restrictions which these soil and groundwater conditions may place on the
proposed site development. Our work included Standard Penetration Test (SPT) borings, solid -
stem auger borings, limited laboratory testing, and engineering analysis. This report documents
our explorations and tests, presents our findings, and summarizes our conclusions and
recommendations.
2.0 SITE INFORMATION AND PROJECT UNDERSTANDING
The Sedona Phase 1 project covers approximately 10 acres of land within an approximately 35-acre
parent tract located on the southwest corner of Edwards Road and 25th Street (St. James Drive) in
St. Lucie County, Florida (within Section 29, Township 35 South, Range 40 East). The location of
the subject site (i.e. the 10-acre Phase 1 portion) is graphically depicted on the Site Vicinity Map
(2016 aerial photograph) as well as on a reproduction of the 1983 USGS Quadrangle Map of "Fort
Pierce, Florida", both presented on Sheet No. 1. The USGS Quadrangle Map depicts the subject
property as being relatively level with an average surface elevation of about 10 feet relative to the
National Geodetic Vertical Datum of 1929.
The infrastructure installation for the Phase 1 site is currently on -going and the proposed T-15
building site is roughly outlined and slightly elevated when compared to the surrounding grades.
According to the USDA NRCS Web Soil Survey, the predominant surficial soil type within the
subject site is the Winder loamy sand (Map Unit ID 55). This soil type is noted to consist of sandy
and loamy marine deposits found on flats within historic marine terraces. The approximate
location of the subject site is shown superimposed on an aerial photograph on Sheet No. 1, along
with a more specific description of the soil type. Further, the USDA Web Soil Survey summary
report is included in Appendix I.
834 Swan Avenue, Port St. Lucie, Florida 34983 Ph: 772.807.9191 Fx: 772-807.9192 www.aaceinc.com
SEDONA RESIDENTIAL DEVELOPMENT- PHASE 1 Page -2-
3182-3192 IVIORNINGDEw LANE (BUILDING T-15)
AACE FILE No.17-249
Based on our conversations and on our cursory review of the project civil engineering plans
(prepared by Culpepper & Terpening, Inc), we understand that Phase I of the Sedona project
consists of constructing thirteen (13) single -story, multi -unit residential dwellings and a
clubhouse/swimming pool complex. Additional project features include roadway construction, as
well as drainage and utility improvements.
Based on your request and after briefly discussing the project with your architect, we understand
that at this point in time it is desired to only have a subsurface exploration and geotechnical
engineering evaluation performed for the T-15 buildingsite. We have not been provided with any
specific structural or architectural information relative to this single -story multi -unit structure.
However, we expect that they will be constructed with load -bearing masonry walls and possibly
isolated columns. For construction of this type we expected maximum wall loads of 1-2 kips per
lineal foot and maximum column loads (if any) of 100 kips. Following our site visit, we expect that
1-2 feet of fill will be placed across the site to raise the general building grades.
3.0 FIELD EXPLORATION PROGRAM
To explore subsurface conditions at theT-15 building site, one (I)Standard Penetration Test (SPT)
boring (ASTM D1586) and two (2) solid -stem auger borings were completed to depths of 10-15
feet below the existing grades. This work was completed on February 24, 2018. The field work
locations shown on Sheet No. 2 were determined in the field by our field crew using the provided
site plan, and tape/wheel measurements and the roughly outlined building pads as reference. The
locations should be considered accurate only to the degree implied by the method of
measurement used. We preliminarily anticipate that the actual locations are within 15 feet of
those shown on Sheet No. 2.
Summaries of AACE's field procedures are included in Appendix II and the individual boring profiles
are presented on the attached Sheet No. 2. Samples obtained during performance of the borings
were visually classified in the field, and representative portions of the samples were transported
to our laboratory in sealed sample jars for further classification. The soil samples recovered from
our explorations will be kept in our laboratory for 60 days, then discarded unless you specifically
request otherwise.
4.0OBSERVED SUBSURFACE CONDITIONS
4.1 General Soil Conditions
Detailed subsurface conditions are illustrated on the soil boring profiles presented on Sheet No.
2. The stratification of the boring profiles represents our interpretation of the field boring logs and
the results of laboratory examinations of the recovered samples. The stratification lines represent
the approximate boundary between soil types. The actual transitions may be more gradual than
implied.
In general, at the locations and depths explored, our borings encountered loose to moderately
dense fine sands (SP), slightly clayey fine sands (SP-SC), and clayey fine sands (SC) to depths of
about 13 feet, followed by soft clay (CL) reaching the termination depth of our deepest borings.
The above soil profile is outlined in general terms only; please refer to Sheet No. 2 for individual
soil profile details.
SEDONA RESIDENTIAL DEVELOPMENT - PHASE 1 Page -3-
3182-3192 MORNINGDEw LANE (BUILDINGT-15)
AACE FILE No.17-249
4.2 Measured Groundwater Level
The groundwater table depth as encountered in the borings during the field investigations is
shown adjacent to the soil profiles on the attached Sheet No. 2. As can be seen, the groundwater
table was generally encountered at depth of about 5.0 feet to about 6.0 feet below the existing
ground surface, with this range likely attributed to similar, localized variations in site topography.
Overall, fluctuations in groundwater levels should be anticipated throughout the year primarily
due to seasonal variations in rainfall and other factors that may vary from the time the borings
were conducted.
5.0 LIMITED LABORATORY TESTING PROGRAM
Our drillers observed the soil recovered from the SPT sampler and augers, placed the recovered
soil samples in moisture proof containers, and maintained a log for each boring. The recovered
soil samples, along with the field boring logs, were transported to our PortSt. Lucie soils laboratory
where they were visually examined by AACE's project engineer to determine their engineering
classification. The visual classification of the samples was performed in accordance with the
Unified Soil Classification System, USCS.
6.0 GEOTECHNICAL ENGINEERING EVALUATION
6.2 General
Based on the findings of our site exploration, our evaluation of subsurface conditions, and
judgment based on our experience with similar projects, we conclude that the soils underlying this
site are generally satisfactory to support the proposed single -story residential building on
conventional spread foundations ora thickened -edge (monolithic) slab. Regardless, in our opinion,
the bearing capacity of the loose near -surface soils should be improved in order to reduce the risk
of unsatisfactory foundation performance. The general soil improvementwe recommend includes
proofrolling the building with a heavy vibratory roller.
Following are specific recommendations for site preparation procedures and foundation design
for the project.
6.2 Site Preparation Recommendations
The existingT-15 building pad should be leveled and compacted with a heavy vibratory roller; any
soft, yielding soils detected should be excavated and replaced with clean, compacted backfill that
conforms with the recommendations below. Sufficient passes should be made during the
proofrolling operations to produce dry densities not less than 98 percent of the modified Proctor
(A5TM D1557) maximum dry density of the compacted material to depths of 2 feet below the
compacted surface, -or 2 feet below the bottom of footings, whichever is lower. In any case, the
building pad should receive not less than 10 overlapping passes, half of them in each of two
perpendicular directions.
After the existing pad surfaces have been compacted and tested to verify that the desired dry
density has been obtained, the building area may be filled to the desired grades. All fill material
should conform to the recommendations below. It should be placed in uniform layers not
exceeding 12 inches in loose thickness. Each layer should be compacted to a dry density not less
than 98 percent of its modified Proctor (ASTM D1557) maximum value.
SEDONA RESIDENTIAL DEVELOPMENT- PHASE 1 Page -4-
3182-3192 MORNINGDEw LANE (BUILDING T-15)
AACE FILE No.17-249
After completion of the general site preparations discussed above, the bottom of foundation
excavations dug through the compacted natural ground, fill or backfill, should be compacted so
as to density soils loosened during or after the excavation process, or washed or sloughed into the
excavation prior to the placement of forms. A vibratory, walk -behind plate compactor can be used
forthisfinal densification immediately prior to the placement of reinforcing steel, with previously
described density requirements to be maintained below the foundation level.
Following removal of foundation forms, backfill around foundations should be placed in lifts six
inches or less in thickness, with each lift individually compacted with a plate tamper. The backfill
should be compacted to a dry density of at least 95 percent of the modified Proctor (ASTM
D-1557) maximum dry density.
All fill material under the buildings should consist of clean sands free of organics and other
deleterious materials. The fill material should have not more than 12 percent by dry weight
passing the U.S. No. 200 sieve, and no particle larger than 3 inches in diameter. Backfill behind
walls, if any, should be particularly pervious, with not more than 4 percent by dry weight passing
the U.S. #200 sieve.
6.3 Foundation and Slab Design
Afterthe foundation soils have been prepared as recommended above, the site should be suitable
forsupporting the proposed single -story residential building construction on conventional shallow
foundations or a thickened -edge (monolithic) slab proportioned for an allowable bearing stress
of 1,500 pounds per square foot [psf], or less. To provide an adequate factor of safety against a
shearing failure in the subsoils, all continuous foundations should be at least 18 inches wide, and
all individual column footings should have a minimum width of 36 inches. Exterior foundations
should bear at least 18 inches below adjacent outside final grades.
Based upon the boring information and the assumed loading conditions, we estimate that the
recommended allowable bearing stress will provide a minimum factor of safety in excess of two
against bearing capacity failure. With the site prepared and the foundations designed and
constructed as recommended, we anticipate total settlements of one inch or less, and differential
settlement between adjacent similarly loaded footings of less than one -quarter of an inch.
Because of the granular nature of the subsurface soils, the majority of the settlements should
occur during construction; post -construction settlement should be minimal.
We recommend that representatives of AACE inspect all footing excavations in order to verify that
footing bearing conditions are consistent with expectations. Foundation concrete should not be
cast over a foundation surface containing topsoil or organic soils, trash of any kind, surface made
muddy by rainfall runoff, or groundwater rise, or loose soil caused by excavation or other
construction work. Reinforcing steel should also be clean at the time of concrete casting. If such
conditions develop during construction, the reinforcing steel must be lifted out and the foundation
surface reconditioned and approved by AACE.
After the ground surface is proofrolled and filled, if necessary, as recommended in this report, the
floor slab can be placed directly on the prepared subgrade. For design purposes, we recommend
using a subgrade reaction modulus of 200 pounds per cubic inch (pci) for the compacted shallow
sands. In our opinion, a highly porous base material is not necessary. We recommend to use a
minimum of 10 mil polyolefin film as the main component of a vapor barrier system.
SEDONA RESIDENTIAL DEVELOPMENT - PHASE 1 Page -5-
3182-3192 MORNINGDEw LANE (BUILDING T-15)
AACE FILE No.17-249
7.0 QUALITY ASSURANCE
We recommend establishing a comprehensive quality control program to verify that all site
preparation and foundation and pavement construction is conducted in accordance with the
appropriate plans and specifications. Materials testing and inspection services should be provided
by Andersen Andre Consulting Engineers, Inc.
An experienced engineering technician should monitor all stripping and grubbing, on a full-time
basis to verify that deleterious materials have been removed. The technician should observe the
proof -rolling operation to verify that the appropriate number of passes are applied to the
subgrade. In -situ density tests should be conducted during filling activities and below all footings,
floor slabs, pavement areas, and within utility/drainage installations to verify that the required
densities have been achieved. In -situ density values should be compared to laboratory Proctor
moisture -density results for each of the different natural and fill soils encountered.
8.0 CLOSURE
The geotechnical evaluation submitted herein is based on the data obtained from the soil boring
profiles presented on Sheets No 2 and 3, and our understanding of the project as described in the
previous. Limitations and conditions to this report are presented in Appendix III.
This report has been prepared in accordance with generally accepted soil and foundation
engineering practices for the exclusive use of Edwards Landing,LLC. No other warranty, expressed
or implied, is made.
We are pleased to be of assistance to you on this phase of your project. When we may be of
further service to you or should you have any questions, please contact us.
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