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Report of Geotechnical Engineering Investigation OIA SOUTH CELL LOT (W340)
AID Project No. GOA16001 Orange County, Florida GEC Project No. 3956G
July 6, 2017 American Infrastructure Development, Inc. 37 North Orange Avenue Suite 500 Orlando, Florida 32801 Attention: Mr. Mark Jansen, P.E., LEED BD+C Subject: Report of Geotechnical Engineering Investigation
OIA SOUTH CELL LOT (W340) AID Project No. GOA16001 Orange County, Florida GEC Project No. 3956G
Dear Mr. Jansen: Geotechnical and Environmental Consultants, Inc. (GEC) is pleased to present this Report of Geotechnical Engineering Investigation for the above-referenced project. This study was performed in general accordance with our Proposal No. 8583G dated March 15, 2016. The purpose of this study was to explore soil and groundwater conditions at the subject site and to use the information obtained to develop geotechnical engineering recommendations regarding site preparation and design of the structure foundations and pavement areas. This report describes our exploration procedures, exhibits the data obtained and presents our conclusions and recommendations regarding the geotechnical engineering aspects of the project. GEC appreciates the opportunity to be of service to you on this project and trusts that the information contained herein is sufficient for your current needs. Should you have any questions concerning the contents of this report, or if we may be of further assistance, please contact us.
GEC Project No. 3956G iii Report of Geotechnical Engineering Investigation
OIA South Cell Lot (W430)
TABLE OF CONTENTS
1.0 SITE AND PROJECT DESCRIPTION ........................................................................................... 1
2.0 NRCS SOIL SURVEY .................................................................................................................. 1
3.0 USGS POTENTIOMETRIC MAP DATA ...................................................................................... 2
4.0 SUBSURFACE EXPLORATION ................................................................................................... 3
4.1 Standard Penetration Test Borings .............................................................................. 3 4.2 Hand Auger Borings ..................................................................................................... 4 4.3 Manual Muck Probes ................................................................................................... 4 4.4 Groundwater Measurement ........................................................................................ 4
5.0 LABORATORY TESTING ............................................................................................................ 4
6.0 DESCRIPTION OF SUBSURFACE CONDITIONS ......................................................................... 5
6.1 Boring Results .............................................................................................................. 6 6.2 Groundwater Levels ..................................................................................................... 7
7.0 ANALYSIS AND DESIGN RECOMMENDATIONS....................................................................... 8
7.1 Foundations ................................................................................................................. 8 7.2 Pavements .................................................................................................................... 9 7.3 Unpaved Access Road for Pond SAR-D ...................................................................... 12 7.4 Stormwater Pond Weir Structure .............................................................................. 12 7.5 Lateral Earth Pressures .............................................................................................. 13 7.6 Uplift Resistance ........................................................................................................ 14
8.0 CONSTRUCTION ISSUES ......................................................................................................... 15
8.1 General Site Preparation ........................................................................................... 15 8.2 Fill Selection, Placement and Compaction ................................................................ 17 8.3 Foundation Subgrade Preparation ............................................................................ 18 8.4 Pavement Subgrade Preparation............................................................................... 18 8.5 Temporary Dewatering .............................................................................................. 19 8.6 Temporary Excavations .............................................................................................. 19
9.0 USE OF THIS REPORT ............................................................................................................. 20
GEC Project No. 3956G iv Report of Geotechnical Engineering Investigation
OIA South Cell Lot (W430)
APPENDIX
Figure 1: USGS Quadrangle and NRCS Soil Survey Maps
Figure 2: Boring Location Plan
Figures 3 - 4: Boring Results
Figure 5: Muck Probe Location Plan and Results
TABLES
Table 7: Summary of Laboratory Test Results
Table 8: Summary of Corrosion Series Test Results
GEC Project No. 3956G 1 Report of Geotechnical Engineering Investigation
OIA South Cell Lot (W430)
1.0 SITE AND PROJECT DESCRIPTION
The project site is located in south Orange County in Orlando, Florida. More specifically the site is
located near the northeast corner of the intersection of Jeff Fuqua Boulevard and South Park Place
approximately 2,500 feet south of the OIA Mid-Cross Field Taxiway. The project site is
approximately 6-acres in area and is currently mostly undeveloped with dense tree coverage. The
site is bordered to the east by the existing Red Lot, to the west by the new South Terminal
currently under construction and to the south by an existing stormwater pond.
The approximate site vicinity is shown on an excerpt of the United States Geological Survey (USGS)
Pine Castle, Florida Quadrangle map on Figure 1 in the Appendix. Based on our review of the
USGS Quadrangle map, the ground surface elevation across the site ranges from approximately
+81 to +90 feet NGVD.
GEC understands that the project will consist of the
construction of a new cell phone parking lot with space for
approximately 200 vehicles. In association with the new
parking lot, approximately 1,200 feet of new paved access
roads are planned. Also planned is the reconstruction of
the existing toll booths for the adjacent Red Lot. The new
toll booths will be reconstructed approximately 500 feet
east of their current locations. In addition, a new weir structure and shell access road to the weir
is planned at the southern end of the existing stormwater pond (SAR-D) south of South Park Place.
The weir structure will be an approximately 48-foot long concrete structure bearing on stabilized
subgrade soils in the southern portion of the existing pond. The structure will include skimmer
poles anchored into the existing pond bottom.
2.0 NRCS SOIL SURVEY
The Natural Resources Conservation Service (NRCS) Soil Survey of Orange County, Florida was
reviewed to obtain surficial soil and groundwater information in the vicinity of the subject site. An
excerpt of the NRCS Soil Survey map showing the approximate site area is presented on Figure 1 in
the Appendix. The NRCS soils near the project site are summarized in the following Table 1:
…the project will consist of… a new
cell phone parking lot… new paved
access roads… reconstruction of
the existing toll booths… a new
weir structure and shell access
road…
GEC Project No. 3956G 2 Report of Geotechnical Engineering Investigation
OIA South Cell Lot (W430)
Table 1
Orange County NRCS Soil Units Summary
Soil
Unit Soil Name
Depth
(in) Soil Description
Unified Soil
Classification
Depth to
Seasonal High
Groundwater
(ft)
Hydrologic
Group
3 Basinger fine sand, depressional,
0 to 1 percent slopes 0 - 80 Fine sand SP-SM +2.0 - 0.0 A/D
26 Ona fine sand
0 - 6
6 - 15
15 - 80
Fine sand
Fine sand, sand
Fine sand, sand
SP, SP-SM
SM, SP-SM
SP, SP-SM
0.5 - 1.0 B/D
34 Pomello fine sand, 0 to 5 percent
slopes
0 - 65
65 - 80
Fine sand
Fine sand
SP-SM
SP 2.0 - 3.5 A
44 Smyrna fine sand, 0 to 2 percent
slopes
0 - 17
17 - 27
27 - 80
Fine sand
Loamy fine sand, fine sand
Fine sand
SP, SP-SM
SP-SM, SM
SP, SP-SM
0.5 - 1.5 A/D
The soils depicted on the NRCS Soil Survey across the majority of project site are Ona fine sand
(Soil Unit 26) and Smyrna fine sand, 0 to 2 percent slopes (Soil Unit 44). In general the soil types
across the project site are classified as fine sand with varying silt content (SP, SP-SM, SM) and are
generally suitable for construction. The NRCS predicts seasonal high groundwater levels to range
from 2 feet above the ground surface to 3.5 feet below the natural ground surface within the
project vicinity.
Information contained in the NRCS Soil Survey is very general and may be outdated. It may not,
therefore, be reflective of actual soil and groundwater conditions, particularly if recent
development in the site vicinity has modified soil conditions or surface/subsurface drainage. The
information obtained from the soil borings provides a better characterization of actual site
conditions.
3.0 USGS POTENTIOMETRIC MAP DATA
Based on our review of the USGS map entitled “The Potentiometric Surface of the Upper Floridan
Aquifer in the St. Johns River Water Management District and Vicinity, Florida, September, 2008”
the potentiometric level of the Floridan aquifer in the vicinity of the subject site is approximately
+49 feet NGVD. Since the existing ground surface elevations in the vicinity of the subject site
ranges from approximately +81 to +90 feet NGVD, artesian flow conditions are not anticipated at
this site. Artesian conditions were not encountered in our soil borings.
GEC Project No. 3956G 3 Report of Geotechnical Engineering Investigation
OIA South Cell Lot (W430)
4.0 SUBSURFACE EXPLORATION
In addition to consulting the sources of information previously discussed for regional and site-
specific soils data, GEC conducted a subsurface exploration to evaluate soil and groundwater
conditions. GEC explored subsurface conditions at the subject site by performing borings at the
locations listed in the following Table 2.
Table 2
Summary of Field Investigation Program
Project Element
*Boring
Type
Boring
No.
Depth
(ft)
Figure
No.
Paved Parking/Drive Areas AB HA-1 to HA-10 1.5 to 5.5 3
Toll Booth Structures SPT TB-1 and TB-2 15 4
Weir Structure SPT B-1 and B-2 30 4
* AB – Auger boring, SPT – Standard Penetration Test boring.
In addition to the borings listed above, manual muck probes were performed along the proposed
weir structure on an approximate 5-foot by 10-foot grid. Also, as requested two manual muck
probes were performed within the existing triangular stormwater pond to help evaluate any
organic removal needed for the stormwater pond expansion and backfilling.
The approximate locations of the borings performed for this study are shown on Figure 2 in the
Appendix. These locations were not surveyed, but rather by using a handheld, sub-meter accuracy
global positioning satellite (GPS) unit (Trimble Geo XH Series). Although these locations are given
only approximately, the methods used to locate them are, in GEC’s opinion, sufficient to meet the
intent of our study. If greater accuracy is desired, a registered Professional Land Surveyor should
be retained to survey these locations.
4.1 Standard Penetration Test Borings
SPT borings were drilled in general accordance with ASTM Procedure D-1586. The boreholes were
advanced by the rotary wash method with bentonite-based mud used as the circulating fluid to
stabilize the borehole. GEC’s field crew obtained SPT samples continuously in the borings to a
depth of 10 feet and at 5-foot depth intervals thereafter. A GEC engineering technician monitored
the drilling operation, and collected, examined and visually classified each sample. He then
packaged representative portions of each sample for transport to our laboratory for further
examination and laboratory testing.
GEC Project No. 3956G 4 Report of Geotechnical Engineering Investigation
OIA South Cell Lot (W430)
4.2 Hand Auger Borings
Our engineering technician performed standard barrel hand auger borings, ASTM D-4700, by
manually turning a 3-inch diameter, 6-inch long sampler into the soil until it was full. He then
retrieved the sampler and visually examined and classified the soil. This procedure was repeated
until the desired termination depth was achieved. Our technician collected representative
samples for further visual examination and classification in our laboratory.
4.3 Manual Muck Probes
Manual muck probes were performed by pushing a slender metal rod into the surficial soil and
evaluating the relative resistance of the soil to manual penetration. Highly organic soils, such as
muck and/or peat, are characteristically very soft and will easily yield to the manual probe.
Manual probes, however, cannot detect peat or muck layers which are present beneath layers of
sand or dense soils which cannot be penetrated by the probe. The probes can also penetrate to
some extent in very loose sands which may be present beneath peat or muck layers. No soil
samples are obtained for visual examination or laboratory testing when using this exploratory
technique. The soil type being penetrated is inferred solely by evaluating the relative resistance of
the soil to penetration. These limitations can lead to some
under-estimation or over-estimation of peat or muck layer
thicknesses. The probe data presented in this report should
be evaluated with these limitations in mind.
4.4 Groundwater Measurement
A GEC engineering technician measured the depth to groundwater in the boreholes at the time of
drilling and again after approximately 24 hours. Once the 24-hour groundwater measurement was
recorded, the boreholes were then backfilled with soil cuttings to prevailing ground surface.
5.0 LABORATORY TESTING
Selected soil samples retrieved from the borings were tested in accordance with Florida Standard
Testing Methods (FM). Florida Standard Testing Methods are adaptations of recognized standard
methods, e.g., ASTM and AASHTO, which have been modified to accommodate Florida’s geological
conditions. The GEC laboratory is reviewed annually by the Construction Materials Engineering
Council, Inc. (CMEC) to verify compliance with FM. Our laboratory testing program is summarized
on the following table:
The probe data presented in this
report should be evaluated with
these limitations in mind.
GEC Project No. 3956G 5 Report of Geotechnical Engineering Investigation
OIA South Cell Lot (W430)
Table 3
Summary of Laboratory Testing Program
Type of Test
Number of
Tests
Grain Size Analysis (FM 1-T 088) 5
Percent Fines (FM 1-T88) 8
Natural Moisture Content (FM 1-T 265) 1
Atterberg Limits (FM 1-T 89/90) 1
Corrosion Series (FM 5-550/551/552/553) 2
The results of our laboratory tests for the SPT borings are shown adjacent to the soil profiles on
the SPT Boring Results sheet. The results of our laboratory testing for the auger borings are
summarized on the Summary of Laboratory Test Results Table (Table 7) in the Appendix.
Corrosion series tests were performed on representative soil and water samples obtained at the
proposed weir structure to evaluate the substructure environmental classification. In accordance
with the FDOT Structure Design Guidelines and the results of our corrosion series test results, the
detailed corrosion test results are presented in Table 8 in the Appendix.
6.0 DESCRIPTION OF SUBSURFACE CONDITIONS
Detailed records of subsurface conditions encountered in our auger and SPT borings are shown on
Figures 3 and 4 in the Appendix. The boring logs describe the soil layers using the Unified Soil
Classification System (USCS) symbol (e.g., SP-SM) and ASTM soil descriptions (e.g., sand with silt).
We based our soil classifications and descriptions on visual examination and the limited laboratory
soil classification testing shown on the Boring Results sheets in the Appendix.
The boring logs indicate subsurface conditions only at the specific boring locations at the time of our
field exploration. Subsurface conditions, including groundwater levels, at other locations of the
subject site may differ from conditions we encountered at the boring locations. Moreover,
conditions at the boring locations can change over time. Groundwater levels fluctuate seasonally,
and soil conditions can be altered by earthmoving operations.
The depths and thicknesses of the subsurface strata indicated on the boring logs were interpolated
between samples obtained at different depths in the borings. The actual transition between soil
layers may be different than indicated. These stratification lines were used for our analytical
GEC Project No. 3956G 6 Report of Geotechnical Engineering Investigation
OIA South Cell Lot (W430)
purposes. Earthwork quantity estimates based on the results of the borings will vary from the
actual quantities measured during construction.
6.1 Boring Results
In general, the SPT borings performed for the toll booth and weir structures typically encountered
the following generalized subsurface profile.
Table 4
Generalized Subsurface Profile for SPT Borings
Soil Borings TB-1, TB-2, B-1 and B-2
Approximate
Layer Depth
(feet) Typical Soil Description
Typical Range
of N-Values
(blows/foot)
0 to 27 Loose to medium dense fine sand with silt to silty fine sand (SP-SM, SM)
with occasional trace organic material and roots 8 to 20
27 to 30 Stiff to very stiff sandy lean clay (CL) 8 to 16
Notable exceptions to the generalized subsurface profile detailed in Table 4 include the following:
Borings TB-1 and TB-2 were terminated at a depth of 15 feet below the existing ground
surface.
Boring TB-1 encountered dense to very dense (N-value of 29 to 54) fine sand with silt to
silty fine sand (SP-SM, SM) from the ground surface to 13 feet below the existing ground
surface.
The auger borings performed within the paved parking/drive areas (HA-1 to HA-10) typically
encountered sands with varying silt content (SP, SP-SM, SM) with occasional trace organic material
and roots to the boring termination depths of 1.5 to 5.5 feet below the existing ground surface.
The manual probes performed for the weir structure and stormwater pond expansion/backfilling
encountered 0 to 5.5 feet of standing water underlain by 0.2
to 1-foot of loose sands/soft sediments. One of the manual
probes encountered 0.5 feet of surficial deleterious material
(muck); however the remainder of the probes did not
One of the manual probes
encountered 0.5 feet of surficial
deleterious material (muck)…
GEC Project No. 3956G 7 Report of Geotechnical Engineering Investigation
OIA South Cell Lot (W430)
encounter any surficial deleterious organic material. The manual probes, however, cannot detect
peat or muck layers which may be present beneath layers of sand or dense soils which cannot be
penetrated by the probe.
Please refer to the Boring Results sheets (Figures 3 and 4) and the Muck Probe Location Plan with
Results (Figure 5) in the Appendix for the specific subsurface profiles at the boring and probe
locations.
6.2 Groundwater Levels
Groundwater levels were encountered at the SPT and auger boring locations at depths ranging
from approximately 0.3 to 3.3 feet below existing ground surface. However, at boring location HA-
1 groundwater was encountered at approximately 1-foot above the existing ground surface. At
boring locations TB-1 and TB-2, groundwater was encountered at approximately 6 feet below the
existing ground surface.
Groundwater levels can vary seasonally and with changes in subsurface conditions between boring
locations. Alterations in surface and/or subsurface drainage brought about by site development
can also affect groundwater levels. Therefore, groundwater depths measured at different times or
at different locations on the site can be expected to vary from those measured by GEC during this
investigation.
For purposes of this report, estimated seasonal high groundwater levels are defined as
groundwater levels that are anticipated at the end of the wet season during a “normal rainfall”
year under pre-development site conditions. We define a “normal rainfall” year as a year in which
rainfall quantity and distribution were at or near historical averages.
Seasonal high groundwater depths were estimated at borings
where groundwater was encountered and typically range
from the ground surface to approximately 1-foot below
existing ground at our boring locations. However, the
seasonal high groundwater depth for borings HA-1, HA-2 and
B-1 is estimated to be above the ground surface, indicated by “AGS” shown adjacent to the boring
profile. Additionally, the seasonal high groundwater depth for borings TB-1 and TB-2 is estimated
to be 4 feet below the existing ground surface. The encountered and estimated seasonal high
groundwater levels are presented on the Boring Results sheets (Figures 3 and 4) in the Appendix.
Seasonal high groundwater
depths… typically range from the
ground surface to approximately
1-foot below existing ground…
GEC Project No. 3956G 8 Report of Geotechnical Engineering Investigation
OIA South Cell Lot (W430)
7.0 CONCLUSIONS AND DESIGN RECOMMENDATIONS
The conclusions and design recommendations contained in this report are based in part on the
data obtained from a limited number of soil samples and the groundwater measurements
obtained from widely-spaced borings. The sampling methods used indicate subsurface conditions
only at the specific boring locations where samples were obtained, only at the time they were
obtained, and only to the depths penetrated. Borings cannot be relied upon to accurately reflect
the variations that usually exist between boring locations and these variations may not become
evident until construction.
If variations from the subsurface conditions described in this report do become evident during
construction or if the project characteristics described in this report change, GEC should be
retained to reevaluate this report’s conclusions and recommendations in light of such changes.
7.1 Foundations
On the basis of the data obtained for this study, in our opinion the site is suitable for support of
the proposed toll structures upon a system of conventional shallow isolated spread footings
and/or continuous strip footings or thickened edge monolithic slabs. This conclusion is contingent
upon the design engineer’s and contractor's adherence to the following recommendations:
Prepare the structure area in accordance with the recommendations in the General Site
Preparation and Fill Selection, Placement and Compaction sections of this report after
final site grading has been performed.
Prepare footing subgrade soils in accordance with the recommendations presented in the
Foundation Subgrade Preparation section of this report.
Use a maximum net allowable soil bearing pressure of
3,000 pounds per square foot in footing design.
Use minimum footing dimensions of 24 inches for isolated spread footings and 18 inches
for strip footings even though the maximum net soil bearing pressure may not be fully
developed in all cases.
Use a maximum net allowable
soil bearing pressure of 3,000
pounds per square foot…
GEC Project No. 3956G 9 Report of Geotechnical Engineering Investigation
OIA South Cell Lot (W430)
Design spread and/or strip foundations so that footings bear at least 18 inches below the
adjacent finished exterior grades.
Design monolithic slabs so that the bottom of thickened slab sections bear at least 12
inches below the adjacent finished exterior grade.
Support floor slabs constructed on-grade on a compacted sand base (95% modified Proctor
for 12 inches).
Overexcavate excessively loose or disturbed soils encountered in the floor slab areas and
replace with sands selected and compacted in accordance with the Fill Selection,
Placement and Compaction section of this report.
Our evaluation of the encountered subsurface conditions indicates that shallow foundations
designed and constructed in accordance with the above recommendations, assuming supporting
loads no heavier than those typical of a one-story building, will experience total settlements of less
than approximately 1 inch and differential settlements between footings of less than ½ inch.
7.2 Pavements
Our study results indicate that the site is suitable for support of conventional flexible or rigid
pavement sections. Flexible pavements can incorporate a limerock base material if at least 2 feet
of vertical separation is provided between the bottom of the limerock base and the seasonal high
groundwater level. A soil-cement base, reclaimed concrete aggregate (RCA) base or asphalt base
material (black base) should be used if this vertical clearance cannot be provided. Furthermore,
pavement underdrains will be needed if seasonal high groundwater levels are within 1-foot of the
bottom of base.
These conclusions are contingent upon preparation of proposed pavement areas in accordance
with GEC’s recommendations in the General Site Preparation; Fill Selection, Placement and
Compaction; and Pavement Subgrade Preparation sections of this report. This includes removing
and replacing any organic soils, if encountered within 2 feet of the bottom of the pavement base.
No deleterious organic soils were encountered at our boring locations shown on Figure 2.
The following recommended minimum pavement sections are typical of similar projects in this
area and are not based on any traffic loading information or formal pavement design, since such
information is not available:
GEC Project No. 3956G 10 Report of Geotechnical Engineering Investigation
OIA South Cell Lot (W430)
For light duty usage, such as automobile parking stalls, we recommend the following
minimum pavement section:
1.5 inches of Structural Asphalt Surface Course.
6 inches of limerock (minimum LBR 100) or 8 inches of soil-cement (minimum 300
psi) or 6 inches of RCA (minimum LBR 150) base course.
12 inches of stabilized subgrade (LBR=40) if limerock or RCA is used.
For heavy duty usage, such as interior parking lot driveways and perimeter roads, we
recommend the following minimum pavement section:
2 inches of Structural Asphalt Surface Course.
8 inches of limerock (minimum LBR 100) or 10 inches of soil-cement (minimum 300
psi) or 8 inches of RCA (minimum LBR 150) base course.
12 inches of stabilized subgrade (LBR=40) if limerock or RCA is used.
For heavy duty usage requiring a concrete pavement section, such as loading docks, we
recommend the following:
6 inches of concrete, 4,000 psi (28-day minimum).
Compact the 12-inch subgrade beneath the concrete to a minimum of 98% of ASTM
D-1557 maximum density.
Concrete pavement design, including jointing of the pavement, should comply with
the specifications of the Portland Cement Association (PCA).
Well-drained soils (unified classification SP) must be utilized beneath the concrete
pavement.
A minimum clearance of 18 inches must be maintained between the bottom of
concrete pavement and the seasonal high water table.
Reclaimed concrete aggregate base material should meet the specifications of the state or local
jurisdiction. If a specification for reclaimed concrete aggregate base is not available, GEC
recommends the following minimum specifications be included in the project specifications:
Reclaimed concrete aggregate base material should meet the following gradation
requirement:
GEC Project No. 3956G 11 Report of Geotechnical Engineering Investigation
OIA South Cell Lot (W430)
Sieve Size Percent by
Weight Passing
2 inch 100
3/4 inch 65 to 95
3/8 inch 40 to 85
No. 4 25 to 65
No. 10 20 to 50
No. 50 5 to 25
No. 200 0 to 10
The reclaimed concrete aggregate base should consist of crushed concrete material derived
from the crushing of hard Portland cement concrete.
Reclaimed concrete aggregate base should not contain plastic soils (i.e.; the minus 0.425
mm (No. 40) sieve material should be non-plastic).
Reclaimed concrete aggregate base should have a minimum limerock bearing ratio (LBR) of
120.
Reclaimed concrete aggregate base should be free of all materials that fall under the
category of solid waste or hazardous materials as defined by the state or local jurisdiction
and should meet all Department of Environmental Protection (DEP) permit requirements
which pertain to construction, demolition and recycling of these materials. Reclaimed
concrete aggregate base should also be substantially free from other deleterious materials
which are not classified as solid waste or hazardous materials and be asbestos free. The
following limits should not be exceeded:
Deleterious Material Percent by
Weight
Bituminous Concrete 1
Bricks 1
Wood and other Organic Substances 0.1
Heavy Metals (except Lead) 0.1
Lead 5 ppm
Reinforcing Steel and Welded Wire Fabric 0.1
Plaster and Gypsum Board 0.1
The reclaimed concrete aggregate base supplier should have DEP permit requirements
section 62-701.730 or be qualified as a clean debris source under DEP rules.
GEC Project No. 3956G 12 Report of Geotechnical Engineering Investigation
OIA South Cell Lot (W430)
7.3 Unpaved Access Road for Pond SAR-D
Our study results indicate that the site can be made suitable for the proposed unpaved driveway
that is located along the southern end of Pond SAR-D. Our conclusions are contingent upon
preparation of proposed pavement areas in accordance with GEC’s recommendations in the
General Site Preparation; Fill Selection, Placement and Compaction; and Pavement Subgrade
Preparation sections of this report.
We understand that the following section will be used for the unpaved driveway.
4 inches of sand stabilized with limerock, shell and/or clay (LBR 100) compacted to 98% of
the modified proctor (ASTM D-1557) maximum density.
12 inches of stabilized subgrade (LBR=40).
A minimum vertical clearance of 18 inches between the bottom of the stabilized layer and
the seasonal high groundwater level is recommended.
Provide adequate grading for positive surface drainage to promote drainage of surface
water from the roadway to reduce water ponding.
Unpaved roadways will likely need more maintenance (i.e.; regrading, leveling, etc.).
7.4 Stormwater Pond Weir Structure
GEC understands the proposed 48-foot long concrete weir structure will be constructed on 12
inches of stabilized subgrade (LBR 40). We recommend that the weir “footprint” area be prepared
in accordance with GEC’s recommendations in the General Site Preparation; Fill selection,
Placement and Compaction; and Foundation Subgrade Preparation section of this report. Soil
and groundwater corrosion series test results at the weir structure are presented in Table 8 in the
Appendix.
GEC understands the skimmer poles will be designed using subsurface data and soil strength
parameters provided in this report. Based on our boring results, the soils appear appropriate for
construction of the skimmer poles. The soil parameters shown below can be used in designing the
skimmer poles.
GEC Project No. 3956G 13 Report of Geotechnical Engineering Investigation
OIA South Cell Lot (W430)
Table 5
Soil Parameters for Design of Skimmer Poles
Soil
Type
Depth Below
Existing Ground
Surface
(feet)
Soil Unit Weight
(pcf)
Soil Angle of
Internal
Friction
(φ)
Cohesion
(psf)
General
N-Value
Range
Average “N”
Value
(blows/foot)
1Estimated Seasonal
High Groundwater
Table Depth
(feet) Moist Saturated Effective
Sand 0 - 27 110 115 55 32 0 8 - 20 13 AGS
Clay 27 - 30 115 120 60 0 1,500 8 - 16 12
1. AGS denotes the groundwater level is estimated to be above the existing ground surface. The height to which water may rise above the ground
surface should be determined by the drainage engineer.
7.5 Lateral Earth Pressures
This section is for use in design of the proposed below ground structures included in the site
design. These recommendations are applicable for structures embedded in the surficial sandy soils
encountered above about 20 feet deep at the site.
Lateral earth pressure for design of below grade structures can be calculated using a hydrostatic
pressure distribution from an equivalent fluid having varying densities for various conditions.
These values assume sandy soil with an angle of internal friction of about 30 degrees, a moist unit
weight of 110 pcf and a saturated unit weight of 115 pcf. The table below summarizes the
recommended equivalent fluid densities for active, passive and at-rest conditions and drained or
undrained conditions. The actual lateral earth pressure will be a function of both the soil unit
weight (submerged or moist) and the depth below ground surface.
Table 6
Lateral Earth Pressures
Lateral Earth Pressure
Condition
Equivalent Fluid Density
Undrained (pcf)
Equivalent Fluid Density
Drained (pcf)
Active 79 36
Passive* 158 330
At-Rest 87 55
*Note – This value is a recommended conservative Equivalent Fluid Density that does not allow
the hydrostatic pressure to contribute to passive earth pressure.
Undrained conditions assume that full water pressure can develop behind the structure, in
addition to the retained earth pressure. This condition should be used if groundwater can occur at
the elevation of the top of the structure. Drained conditions assume no hydrostatic (water)
GEC Project No. 3956G 14 Report of Geotechnical Engineering Investigation
OIA South Cell Lot (W430)
pressure can develop due to positive drainage behind the structure, and includes only the moist
soil earth pressure.
Frictional resistance at the bottom of the structures to limit sliding can be calculated by multiplying
the bottom contact pressure by a coefficient of friction of 0.5. We note that the values for earth
pressure and frictional resistance do not contain a factor of safety. We have conservatively
assumed that hydrostatic pressure does not contribute to passive earth pressure. Appropriate
factors of safety should be selected by the structural engineer providing the structural design.
7.6 Uplift Resistance
Permanent structures submerged below the water table will be subjected to uplift forces caused
by buoyancy. The components resisting this buoyancy include: 1) the total weight of the structure
divided by an appropriate factor of safety; 2) the buoyant weight of soil overlying the structure;
and 3) the shearing forces that act on shear planes that radiate vertically upward from the edges of
the structure to the ground surface. The allowable unit shearing resistance may be determined by
the following formula:
Allowable Unit Shearing Resistance, F = Koγmh (2/3 tanΦ)/S.F. (Above groundwater table)
Allowable Unit Shearing Resistance, F = Ko(γs - γW) h (2/3 tanΦ)/S.F. (Below groundwater
table)
Where:
F = unit shearing resistance (psf)
Ko = coefficient of earth pressure at rest = 0.5
γm = unit weight of moist soil = 110 pcf
γs = saturated unit weight of soil = 115 pcf
γW = unit weight of water = 62.4 pcf
h = vertical depth below grade at which shearing resistance is determined
Φ = angle of internal friction of the soil = 30 degrees
S.F. = safety factor = 1.5
GEC Project No. 3956G 15 Report of Geotechnical Engineering Investigation
OIA South Cell Lot (W430)
The values given for the above parameters assume that the
permanent structure is covered by clean, well compacted
granular backfill that extends horizontally at least 5 feet
beyond the structures. For this uplift design we
recommend a worst case scenario of assuming
groundwater at the ground surface. An appropriate safety factor should also be included in the
design of the structure.
8.0 CONSTRUCTION ISSUES
The following sections of this report include comments on issues related to the geotechnical
aspects of the proposed construction. These recommendations are not intended to dictate
construction methods or sequences. Instead, they are furnished as an aid to design professionals
and to identify important construction issues related to foundation and earthwork plans and
specifications. These recommendations may also be useful to personnel who observe construction
activity.
Prospective contractors for this project should evaluate potential construction problems on the
basis of their review of the contract documents, their own knowledge and experience in the local
area, and on the basis of similar projects in other localities, taking into account their own proposed
means and methods.
8.1 General Site Preparation
Our recommendations regarding routine site preparation of the structure and pavement areas can
be summarized as follows:
Remove all vegetation, organic topsoil, major root systems, buried utilities, and other
deleterious materials from beneath and to a minimum of 5 feet beyond the proposed
structure and pavement limits. Standard clearing, grubbing, and topsoil stripping
procedures should be appropriate for most of this site.
Perform temporary dewatering as required to achieve proper site preparation, fill
placement and compaction.
Allow a Geotechnical Engineer to inspect the site after it has been stripped to verify
adequate topsoil and vegetation removal and also to observe subsequent proofrolling.
For this uplift design we
recommend… assuming
groundwater at the ground
surface.
GEC Project No. 3956G 16 Report of Geotechnical Engineering Investigation
OIA South Cell Lot (W430)
In structure and pavement areas where fill is required, proofroll the stripped ground
surface using a large vibratory roller (Dynapac CA-25 or equivalent). Proofroll cut areas
after excavation to proposed grade to allow adequate compaction of the exposed subsoil.
Exercise extreme caution when operating vibratory equipment near existing structures.
Nearby structures may be adversely affected by vibratory rolling operations. Provisions
should be made to monitor adjacent buildings for excessive vibrations. Operate roller in
static mode if excessive vibrations are experienced by any nearby structures or if the soil
subgrade becomes unstable.
Proofroll the structure and pavement areas with a minimum of 10 overlapping passes in
each of two perpendicular directions. Allow a Geotechnical Engineer, or his representative,
to observe proofrolling operations. The purposes of the proofrolling will be to detect
unstable soils that yield when subjected to compaction and to densify the near-surface
loose sands for support of shallow foundations, soil supported floor slabs, and new
pavements.
Remove material that yields excessively during proofrolling and replace with fill selected
and compacted as described in the next section of this report. The Geotechnical Engineer,
based on his observations, should recommend the nature and extent of any remedial work.
If the soil subgrade is saturated, or if the fill is at a moisture content over “optimum”, then
instability may occur and the contractor will be required to implement remedial measures
to successfully place and compact the fill.
Silty sand (SM) may be exposed at the compaction surface during site preparation. These
soils can be unstable during proofrolling if they contain excess moisture. The contractor
should be prepared to manipulate the moisture content of unstable subgrade soils as
necessary to achieve stability and compaction requirements.
Continue proofrolling until the soil at a depth of 12 inches below the compaction surface
has attained a minimum of 95% of the soil's modified Proctor maximum dry density as
determined by ASTM Standard D-1557.
Allow an Engineering Technician, working under the direction of a Geotechnical Engineer
registered in the State of Florida, to perform in-place density tests to verify that the
required degree of compaction has been achieved.
GEC Project No. 3956G 17 Report of Geotechnical Engineering Investigation
OIA South Cell Lot (W430)
8.2 Fill Selection, Placement and Compaction
After the contractor proofrolls the site in accordance with the above recommendations, the
contractor should place and compact fill required to bring the site to final grade. We recommend
that all fill be selected, placed and compacted as follows:
Use fill material comprised of non-plastic sands with less than about 12% fines content. The
fill should not contain any significant amount of organic soil (less than 3% by weight) and
should be substantially free from roots or other organic or deleterious materials.
Sands excavated above the water table may have to be wetted to attain the moisture
content needed to achieve the required degree of compaction.
Place fill in level lifts no thicker than 12 inches. Thinner lifts may be needed to achieve
compaction in the silty sand.
Compact fill to a minimum of 95% of the soil's modified Proctor maximum dry density as
determined by ASTM Standard D-1557 for each lift of fill placed.
Allow an Engineering Technician, working under the direction of a registered Geotechnical
Engineer, to perform in-place density tests to verify that the recommended degree of
compaction has been achieved.
Extend fill a minimum of 10 feet beyond building limits to prevent possible erosion or
undermining of footing bearing soils.
Provide fill slopes no steeper than 2 horizontal to 1 vertical.
Compact fill placed in utility trenches to the specifications stated above. However, in
restricted working areas, where use of a large vibratory roller is not feasible, compact fill
with lightweight, hand-guided compaction equipment and limit lift thicknesses to a
maximum of 6 inches.
All excavations including utility trenches, should comply with the recommendations
included in the Temporary Excavations section of this report.
GEC Project No. 3956G 18 Report of Geotechnical Engineering Investigation
OIA South Cell Lot (W430)
8.3 Foundation Subgrade Preparation
We recommend the following steps be taken during footing excavation and subgrade preparation:
Excavate footings in accordance with the recommendations presented in the Temporary
Excavations section of this report.
Compact footing subgrade soils to a depth of 12 inches below footing/structure bearing
elevations to a minimum of 95% of the soil's modified Proctor maximum dry density as
determined by ASTM Standard D-1557.
Perform in-place density tests at 12 inches below the footing bearing elevation to verify
footing subgrade density.
Allow a Geotechnical Engineer, or his representative, to observe footing excavation
conditions prior to placement of reinforcing steel or concrete.
On the basis of the Geotechnical Engineer's observations, remove any unsuitable material
encountered in the footing excavations and replace with sand selected and compacted in
accordance with the Fill Selection, Placement and Compaction section of this report.
8.4 Pavement Subgrade Preparation
Our general recommendations for the pavement subgrade are as follows:
Prepare pavement areas in accordance with the General Site Preparation and Fill
Selection, Placement and Compaction sections of this report.
Compact the 12-inch subgrade beneath the base to a minimum of 98% of ASTM D-1557
maximum density. Perform in-place density tests to verify pavement subgrade density.
Stabilize the subgrade beneath a limerock or RCA base to a minimum Limerock Bearing
Ratio (LBR) of 40.
Stabilization is not required beneath a soil-cement base or rigid (concrete) pavement.
However, the lack of subgrade stabilization should be considered in the pavement design.
GEC Project No. 3956G 19 Report of Geotechnical Engineering Investigation
OIA South Cell Lot (W430)
8.5 Temporary Dewatering
Depending on groundwater levels at the time of construction, excavation depths and final design
grades, temporary dewatering may be required to facilitate stable excavations and placement and
compaction of fill. The contractor should be required to provide a dewatering system which
maintains groundwater levels at least 2 feet below compaction surfaces, including the bottom of
all excavations. A system of ditches and sumps may be sufficient in some instances to achieve
adequate dewatering, but the contractor should be prepared to install wellpoint dewatering
systems as necessary.
Additionally, the contractor must provide positive site drainage during the site preparation and fill
placement. Surface runoff should not be allowed to accumulate. Temporary rim ditches may be
required to facilitate site preparation.
8.6 Temporary Excavations
The owner and the contractor should be familiar with local, state and federal safety regulations,
including current Occupational Safety and Health Administration (OSHA) excavation and trench
safety standards. Construction site safety is the responsibility of the contractor. The contractor
should also be responsible for the means, methods, techniques, sequences, and operations of the
construction.
The contractor should be aware that slope height, slope inclination, and excavation depths
(including utility trench excavations) should not exceed those specified in local, state, or federal
safety regulations; e.g., OSHA Health and Safety Standards for Excavations, 29 CFR Part 1926. OSHA
regulations are strictly enforced and, if not followed, the owner, contractor, earthwork
subcontractor or utility subcontractor could be liable for substantial penalties.
The soil encountered in the borings performed by GEC at this site is primarily sand with varying
amounts of silt. We anticipate that OSHA will classify these materials as Type C. OSHA
recommends a maximum temporary slope inclination of 1.5 horizontal to 1 vertical for this soil
type. Soils encountered in the construction excavations may vary significantly across the site. Our
soil classifications are based on the materials encountered in widely-spaced borings. The
contractor should verify that similar conditions exist throughout the proposed excavation area. If
different subsurface conditions are encountered at the time of construction, GEC should be
contacted immediately to evaluate the conditions encountered.
GEC Project No. 3956G 20 Report of Geotechnical Engineering Investigation
OIA South Cell Lot (W430)
9.0 USE OF THIS REPORT
GEC has prepared this report for the exclusive use of our client, American Infrastructure
Development, Inc., and for specific application to our client’s project. GEC will not be held
responsible for any third party’s interpretation or use of this report’s subsurface data or
engineering analysis without our written authorization.
The sole purpose of the borings performed by GEC at this site was to obtain indications of
subsurface conditions as part of a geotechnical exploration program. GEC has not subjected any
soil samples to analysis for contaminants.
GEC has strived to provide the services described in this report in a manner consistent with that
level of care and skill ordinarily exercised by members of our profession currently practicing in
Central Florida. No other representation is made or implied in this document.
The conclusions or recommendations of this report should be disregarded if the nature, design, or
location of the facilities is changed. If such changes are contemplated, GEC should be retained to
review the new plans to assess the applicability of this report in light of proposed changes.
APPENDIX
USGS QUADRANGLE AND
NRCS SOIL SURVEY MAPS
44
44
1
44
41
41
34
34
99
44
1
99
3
399
34
44
3
50
99
3
3
3
3
99
3
44
34
42
26
34
99
41
3
34
43
44
99
3
3
54
99
99
26
3
3
99
3
34
3
3
3
99
3
3
373
3
423
42
44
99
34
26
44
3
37
37
2099
37
3
26
9999
99
3
34
42
44
2634
34
415099
34
3
3
34
99
54
99
41
3
37
33
37
99
99
34
34
3
99
37
34
3
37
37
34
3
3
3
344
34
99
3 3
34
J:\Jobs - Drafting\3956G OIA Cell Lot\3956Gmaps.mxd 7/6/2017
Geotechnical and Environmental919 Lake Baldwin LaneOrlando, FL 32814PH (407) 898-1818 FAX (407) 898-1837Certificate of Authorization No. 00005882
CHRISTOPHER P. MEYER P.E. NO. 49328
PROJECT NO.3956G USGS QUADRANGLE AND NRCS SOIL SURVEY MAPS
OIA SOUTH CELL LOTConsultants, Inc.
FIGURENO.
17/6/2017
DATE
SKRDRAWN BY
VEW 82275CHECKED BY
CPM 49328CHECKED BY
0 2,0001,000
Feet:
USGS Pine Castle, FL Quadrangle MapSection: 10Township: 24 SouthRange: 30 East
NRCS Soil Survey of Orange County, FLOrange County Map Unit Legend 3 - Basinger fine sand, depressional, 0 to 1 percent slopes26 - Ona fine sand, 0 to 2 percent slopes34 - Pomello fine sand, 0 to 5 percent slopes44 - Smyrna-Smyrna, wet, fine sand, 0 to 2 percent slopes
ApproximateProject Site
ApproximateProject Site
GEC
BORING LOCATION PLAN
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HA-8
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HA-6
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HA-4
HA-3
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HA-1
B-2B-1
J:\Jobs - Drafting\3956G OIA Cell Lot\3956G.mxd 7/6/2017
Geotechnical and Environmental
: 919 Lake Baldwin LaneOrlando, FL 32814PH (407) 898-1818 FAX (407) 898-1837Certificate of Authorization No. 00005882
CHRISTOPHER P. MEYER P.E. NO. 49328GEC PROJECT NO.
3956G BORING LOCATION PLAN
OIA SOUTH CELL LOTConsultants, Inc.
FIGURENO.
27/6/2017
DATE
SKRDRAWN BY
VEW 82275CHECKED BY
CPM 49328CHECKED BY
0 200100
Feet
APPROXIMATE SPT BORING LOCATIONAPPROXIMATE AUGER BORING LOCATION
&<
&<
PROPOSED WEIR STRUCTURE
PROPOSED TOLL BOOTH
PROPOSED TOLL BOOTHSOUTH PARK PLACE
PROPOSED CELL LOT AREA
BORING RESULTS
MUCK PROBE LOCATION PLAN
WITH RESULTS
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J:\Jobs - Drafting\3956G OIA Cell Lot\3956Gprobe.mxd 7/6/2017
Geotechnical and Environmental
: 919 Lake Baldwin LaneOrlando, FL 32814PH (407) 898-1818 FAX (407) 898-1837Certificate of Authorization No. 00005882
CHRISTOPHER P. MEYER P.E. NO. 49328GEC PROJECT NO.
3956G MUCK PROBE LOCATION PLAN WITH RESULTS
OIA SOUTH CELL LOTConsultants, Inc.
FIGURENO.
57/6/2017
DATE
SKRDRAWN BY
VEW 82275CHECKED BY
CPM 49328CHECKED BY
0 200100
Feet
APPROXIMATE SPT BORING LOCATIONAPPROXIMATE AUGER BORING LOCATIONAPPROXIMATE LOCATION OF MUCK PROBE
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&.HA-10 5.5 | 0.0 | 1.0
5.5 | 0.0 | 1.0
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B-2
B-1
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0 5025
Feet
0 2010
Feet
MUCK PROBE LOCATION 'A' DETAIL
MUCK PROBE LOCATION 'B' DETAIL
STANDING WATER DEPTH (FT.)
SURFICIAL MUCK THICKNESS (FT.)
1.3 | 0.0 | 0.2
SEE MUCK PROBELOCATION 'A' DETAIL
SEE MUCK PROBELOCATION 'B' DETAIL
SOFT SEDIMENT / SAND
0.0 | 0.0 | 1.00.0 | 0.0 | 1.0
0.0 | 0.5 | 0.51.0 | 0.0 | 0.1
1.3 | 0.0 | 0.2
0.0 | 0.0 | 0.7
1.0 | 0.0 | 0.21.4 | 0.0 | 0.2
SUMMARY OF LABORATORY
TEST RESULTS
Table 7Summary of Laboratory Test Results
OIA South Cell Lot (W430)GEC Project No. 3956G
Page 1 of 1
Sample Moisture OrganicBoring Depth #10 #40 #60 #100 #200 Content Liquid Plasticity Content Unified
No. (feet) Sieve Sieve Sieve Sieve Sieve (%) Limit Index (%) Class.HA-2 0 - 3 100 96 85 30 8 --- --- --- --- SP-SMHA-3 2.5 - 3.5 100 96 84 30 7 --- --- --- --- SP-SMHA-6 0 - 2 100 97 85 30 9 --- --- --- --- SP-SMHA-7 0 - 5 100 95 82 26 7 --- --- --- --- SP-SMHA-8 3.5 - 5 100 97 87 34 18 --- --- --- --- SM
Percent Passing by Weight Atterberg Limits
SUMMARY OF CORROSION
SERIES TEST RESULTS
Table 8Summary of Corrosion Series Test Results
OIA South Cell Lot (W430)GEC Project No. 3956G
Page 1 of 1
Concrete SteelB-1 Water --- 7.0 5,200 25 17 Slightly Aggressive Slightly AggressiveB-2 SM 2 - 8 6.2 21,000 45 < 5 Slightly Aggressive Moderately Aggressive
Chlorides (ppm)
Sulfates (ppm)
Substructural Environmental ClassificationBoring
No.Unified Soil
Classification
Sample Depth (feet) pH
Minimum Resistivity (ohm-cm)