Report of Geotechnical Engineering Investigation OIA … Project No. 3956G 1 Report of Geotechnical...

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


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


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…



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.



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.



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.



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



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)…



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…



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…



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:



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:



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.



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.



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)



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



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.



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.



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.



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.



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.



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

&<

&<

&<

&<

&<

&<

&<

&<

&<

&<

&<

&<

&<&<

HA-9

HA-10

TB-2TB-1

HA-8

HA-7

HA-6

HA-5

HA-4

HA-3

HA-2

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


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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HA-9

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HA-8

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HA-6

HA-5

HA-4

HA-3

HA-2

B-2B-1

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


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

&<

&<

&<

&.

&.HA-10 5.5 | 0.0 | 1.0

5.5 | 0.0 | 1.0

&<

&<

&.&.

&.

&.

&.

&.

&.

&.

B-2

B-1

&.

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)

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