H4185018_Collins_St_Mast_Arms_S&S.pdf

REPORT COVER PAGE

Geotechnical Engineering Report

Collins Street Mast Arms Plant City, Hillsborough County, Florida

October 30, 2019 Terracon Project No. PH4185018

Prepared for:

City of Plant City

Plant City, Florida

Prepared by:

Terracon Consultants, Inc.

Tampa, Florida

Terracon Consul tants, Inc. 5463 W. Waters Ave. , Suite 830 Tampa, FL 33634 P (813) 221-0050 F (813) 221-0051 terracon.com

REPORT COVER LETTER TO SIGN

October 30, 2019

City of Plant City 302 W Reynolds Street Plant City, Florida 33564

Re: Geotechnical Engineering Report Collins Street Mast Arms Intersection of Collins Street and Alabama Street Plant City, Hillsborough County, Florida Terracon Project No. PH4185018

Dear Ms. Austin:

We have completed the Geotechnical Engineering services for the above referenced project. This study was performed in general accordance with Terracon Proposal No. PH4185018 dated February 2, 2018. This report presents the findings of the subsurface exploration and provides geotechnical recommendations concerning soil parameters for the design of two mast arms at the referenced intersection.

We appreciate the opportunity to be of service to you on this project. If you have any questions concerning this report or if we may be of further service, please contact us.

Sincerely, Terracon Consultants, Inc.

Certificate of Authorization Number 8830

Stephen C. Knauss, P.E., D.GE Keith D. Bennett, P.E.

Senior Engineer Senior Geotechnical Engineer Florida Registration No.: 28202 Florida Registration No.: 33075

This report has been digitally signed and sealed by Stephen C. Knauss, P.E. on date adjacent to the seal.

Printed copies of this document are not considered signed and sealed and the signature must be verified on any electronic copies

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REPORT TOPICS

INTRODUCTION

SITE CONDITIONS

PROJECT DESCRIPTION

GEOTECHNICAL CHARACTERIZATION

GEOTECHNICAL OVERVIEW

SOIL PARAMETERS

CONSTRUCTION CONSIDERATIONS

GENERAL COMMENTS

FIGURES

Note: This report was originally delivered in a web-based format. Orange Bold text in the report indicates a referenced section heading. The PDF version also includes hyperlinks which direct the reader to that section and clicking on the GeoReport logo will bring you back to this page. For more interactive features, please view your project online at client.terracon.com.

ATTACHMENTS

EXPLORATION AND TESTING PROCEDURES

SITE LOCATION AND EXPLORATION PLANS

EXPLORATION RESULTS

SUPPORTING INFORMATION

Note: Refer to each individual Attachment for a listing of contents.

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INTRODUC TION

Geotechnical Engineering Report Collins Street Mast Arms

Intersection of Collins Street and Alabama Street Plant City, Hillsborough County, Florida

Terracon Project No. PH4185018 October 30, 2019

INTRODUCTION

This report presents the results of our subsurface exploration and geotechnical engineering services performed for the proposed mast arms to be located at Intersection of Collins Street and Alabama Street in Plant City, Hillsborough County, Florida. The purpose of these services is to provide information and geotechnical engineering relative to:

■ Subsurface soil conditions

■ Groundwater conditions

■ Soil Parameters for mast arm design

The geotechnical engineering Scope of Services for this project included the advancement of two test borings to approximately 25 feet below existing site grades.

Maps showing the site and boring locations are shown in the Site Location and Exploration Plan sections, respectively.

SITE CONDITIONS

The following description of site conditions is derived from our site visit in association with the field exploration and our review of publicly available geologic and topographic maps.

Item Description

Site Information The site is at the intersection of South Collins Street and Alabama Avenue.

Latitude/Longitude 28.0110°/-82.1222° See Site Location

Existing Improvements

Collins Street is a 4-lane urban roadway and Alabama Street is a 2-lane urban roadway.

Current Ground Cover

The ground cover includes asphalt and concrete pavement as well as limited areas of grass.

Existing Topography The area of the site is relatively level at about elevation +130 feet.

Collins Street Mast Arms ■ Plant City, Hillsborough County, Florida October 30, 2019 ■ Terracon Project No. PH4185018

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PROJECT DESCRIPTION

Our initial understanding of the project was provided in our proposal and was discussed during project planning. A period of collaboration has transpired since the project was initiated, and our final understanding of the project conditions is as follows:

Item Description

Information Provided Information was provided by Kimley-Horn in a series of emails at the time that the proposal was prepared in February 2018.

Proposed Structures Mast Arms are to be constructed on the northeast and southwest corners of the intersection of Collins Street and Alabama Street

Finished Grade Within 2 feet of existing grade.

Estimated Start of Construction 2020

GEOTECHNICAL CHARACTERIZATION

Subsurface Conditions

We have developed a general characterization of the subsurface conditions based upon our review of the subsurface exploration and our understanding of the project. This characterization, termed GeoModel, forms the basis of our geotechnical parameters. Conditions encountered at each exploration point are indicated on the individual logs. The individual logs can be found in the Exploration Results section and the GeoModel can be found in the Figures section of this report.

As part of our analyses, we identified the following model layers within the subsurface profile. For a more detailed view of the model layer depths at each boring location, refer to the GeoModel.

Model Layer

Layer Name General Description Relative Density

Sand Poorly graded Sand (SP), Poorly graded Sand with silt (SP-SM) and Poorly graded Sand with clay (SP-SC)

Loose to medium dense

2 Clayey Sand

Clayey Sand (SC) Very loose to dense

It should be noted that the initial 8 feet of soil in boring B-1 may be fill based on some rocks that were found in the samples. In addition, boring B-2 initially encountered about 3 inches of concrete.

October 30, 2019 ■ Terracon Project No. PH4185018

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Groundwater

Groundwater was measured during drilling and the following table provides the depth to groundwater.

Boring Depth to Groundwater (feet)

B-1 Encountered but not measured

B-2 4

Based on the results of the field work, we estimate that the seasonal high groundwater level will be about 3 feet below the current ground surface.

GEOTECHNICAL OVERVIEW

With the exception of the possible fill encountered in boring B-1, the borings indicated similar soils are present at the two corners, but that the relative density of those soils varies significantly. As a result, the soil parameters for the foundation design of the mast arms will differ.

The General Comments section provides an understanding of the report limitations.

SOIL PARAMETERS

Tables providing the soil parameters that can used with the FDOT MATHCAD program to design the mat arm foundations are attached to this report in the Supporting Information.

CONSTRUCTION CONSIDERATIONS

As noted, the estimated seasonal high groundwater table will be on the order of 3 feet below the ground surface. As a result, the excavation for the foundations will require wet drilled shaft construction procedures be used. The very loose soil conditions encountered in boring B-1 may necessitate the use of full-length casing to maintain the excavation. It is also likely that additional concrete will be necessary to complete the shaft.

GENERAL COMMENTS

Our analysis and opinions are based upon our understanding of the project, the geotechnical conditions in the area, and the data obtained from our site exploration. Natural variations will

October 30, 2019 ■ Terracon Project No. PH4185018

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Our Scope of Services does not include either specifically or by implication any environmental or biological (e.g., mold, fungi, bacteria) assessment of the site or identification or prevention of pollutants, hazardous materials or conditions. If the owner is concerned about the potential for such contamination or pollution, other studies should be undertaken.

Our services and any correspondence or collaboration through this system are intended for the sole benefit and exclusive use of our client for specific application to the project discussed and are accomplished in accordance with generally accepted geotechnical engineering practices with no third-party beneficiaries intended. Any third-party access to services or correspondence is solely for information purposes to support the services provided by Terracon to our client.

Reliance upon the services and any work product is limited to our client and is not intended for third parties. Any use or reliance of the provided information by third parties is done solely at their own risk. No warranties, either express or implied, are intended or made.

Site characteristics as provided are for design purposes and not to estimate excavation cost. Any use of our report in that regard is done at the sole risk of the excavating cost estimator as there may be variations on the site that are not apparent in the data that could significantly impact excavation cost. Any parties charged with estimating excavation costs should seek their own site characterization for specific purposes to obtain the specific level of detail necessary for costing.

Site safety, and cost estimating including, excavation support, and dewatering requirements/design are the responsibility of others. If changes in the nature, design, or location of the project are planned, our conclusions and recommendations shall not be considered valid unless we review the changes and either verify or modify our conclusions in writing.

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FIGURES

Contents:

GeoModel

D

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TH

B

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W G

R A

D E

(F ee

t) City of Plant City Roadway Improvements Plant City, FL Terracon Project No. H4185018

Layering shown on this figure has been developed by the geotechnical engineer for purposes of modeling the subsurface conditions as required for the subsequent geotechnical engineering for this project.

Numbers adjacent to soil column indicate depth below ground surface.

NOTES:

B-1 B-2

GEOMODEL

This is not a cross section. This is intended to display the Geotechnical Model only. See individual logs for more detailed conditions.

First Water Observation

LEGEND

Poorly-graded Sand with Silt

Poorly-graded Sand

Clayey Sand

Concrete

Poorly-graded Sand with Clay

Model Layer General DescriptionLayer Name

Poorly graded Sand (SP), Poorly graded Sand with silt (SP-SM) and Poorly graded Sand with clay (SP-SC)1

Clayey Sand (SC)2

SAND

CLAYEY SAND

ATTACHMENTS

October 30, 2019 ■ Terracon Project No. PH4185018

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EXPLORATION AND TESTING PROCEDURES

Field Exploration

Number of Borings Boring Depth (feet) Planned Location

2 25 Mast arm locations

Boring Layout and Elevations: Unless otherwise noted, Terracon personnel provided the boring layout. Coordinates were obtained with a handheld GPS unit (estimated horizontal accuracy of about ±10 feet). The borings were located to avoid existing marked underground utilities as well as overhead utilities. If elevations and a more precise boring layout are desired, we recommend borings be surveyed.

Subsurface Exploration Procedures: We advanced the borings with a track-mounted rotary drill rig using slurry drilling methods. Initially, a hand auger was used to advance the boring to minimize the potential for damaging underground utilities. Five samples were obtained in the upper 10 feet of each boring and at intervals of 5 feet thereafter. In the split-barrel sampling procedure, a standard 2-inch outer diameter split-barrel sampling spoon was driven into the ground by a 140-pound automatic hammer falling a distance of 30 inches. The number of blows required to advance the sampling spoon for each six-inch penetration is recorded. The 2nd and 3rd six-increments are added together and reported as the Standard Penetration Test (SPT) resistance value. The SPT resistance values, also referred to as N-values, are indicated on the boring logs at the test depths. We observed and recorded groundwater levels during drilling and sampling. For safety purposes, all borings were backfilled with bentonite chips after their completion.

Pavements were patched with pre-mixed concrete.

The sampling depths, penetration distances, and other sampling information was recorded on the field boring logs. The samples were placed in appropriate containers and taken to our soil laboratory for testing and classification by a Geotechnical Engineer. Our exploration team prepared field boring logs as part of the drilling operations. These field logs included visual classifications of the materials encountered during drilling and our interpretation of the subsurface conditions between samples. Final boring logs were prepared from the field logs. The final boring logs represent the Geotechnical Engineer's interpretation of the field logs and include modifications based on observations and tests of the samples in our laboratory.

Laboratory Testing

The project engineer reviewed the field data to understand the engineering properties of the various soil strata, as necessary, for this project. The laboratory testing program included visual classification of soil samples by an engineer. Based on the material’s texture and plasticity, we

October 30, 2019 ■ Terracon Project No. PH4185018

Responsive ■ Resourceful ■ Reliable EXPLORATION AND TESTING PROCEDURES 2 of 2 described and classified the soil samples in accordance with the Unified Soil Classification System.

SITE LOCATION AND EXPLORATION PLANS

Contents:

Site Location Plan Exploration Plan

SITE LOCATION

October 30, 2019 ■ Terracon Project No. PH4185018

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SITE LOCA TION

DIAGRAM IS FOR GENERAL LOCATION ONLY, AND IS NOT INTENDED FOR CONSTRUCTION PURPOSES MAP PROVIDED BY MICROSOFT BING MAPS

EXPLORATION PLAN

October 30, 2019 ■ Terracon Project No. PH4185018

Note to Preparer: This is a large table with outside borders. Just click inside the table above this text box, then paste your GIS Toolbox image.

When paragraph markers are turned on you may notice a line of hidden text above and outside the table – please leave that alone. Limit editing to inside the table.

The line at the bottom about the general location is a separate table line. You can edit it as desired, but try to keep to a single line of text to avoid reformatting the page.

EXPLORATION P LAN

DIAGRAM IS FOR GENERAL LOCATION ONLY, AND IS NOT INTENDED FOR CONSTRUCTION PURPOSES MAP PROVIDED BY MICROSOFT BING MAPS

EXPLORATION RESULTS

Boring Logs (B-1 and B-2)

4-6-5-8 N=11

12-12-16-31 N=28

5-7-4-4 N=11

WOH/18"

WOH/6"-3-2

N=5

4-5-4 N=9

FILL - POORLY GRADED SAND WITH SILT (SP-SM), fine grained, dark brown

FILL - POORLY GRADED SAND (SP), fine grained, light brown with rocks, light gray, medium dense

FILL - CLAYEY SAND (SC), with rocks, fine grained, light gray, dense

CLAYEY SAND (SC), wirh shell fragments, fine grained, light gray, medium dense very loose

VERY CLAYEY SAND (SC), fine grained, light gray, loose

CLAYEY SAND (SC), fine grained, light gray, medium dense

Boring Terminated at 25 Feet

3.0

6.0

8.0

18.0

21.0

25.0

Hammer Type: AutomaticStratification lines are approximate. In-situ, the transition may be gradual.

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LL-PL-PI

LOCATION See Exploration Plan

Latitude: 28.0112° Longitude: -82.1221°

G R

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M O

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DEPTH

Advancement Method:

Mud rotary

Abandonment Method:

Boring backfilled with soil cuttings and bentonite chips upon completion.

Notes:

Project No.: H4185018

Drill Rig: D-25

BORING LOG NO. B-1

Kimley-Horn and Associates IncCLIENT:

Tampa, FL

Driller: C. Hicks

Boring Completed: 09-11-2019

PROJECT: City of Plant City Roadway Improvements

See Exploration and Testing Procedures for a description of field and laboratory procedures used and additional data (If any).

See Supporting Information for explanation of symbols and abbreviations.

Collins Street Plant City, FL

SITE:

Boring Started: 09-11-2019

5463 W Waters Ave, Ste 830 Tampa, FL

Groundwater encountered but not measured

WATER LEVEL OBSERVATIONS

SA

M

PL

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TY

PE

5-6-10-8 N=16

4-3-5-5 N=8

11-4-3-6 N=7

3-4-4 N=8

4-6-6 N=12

4-4-5 N=9

3 INCHES CONCRETE

POORLY GRADED SAND WITH SILT (SP-SM), fine grained, dark brown

POORLY GRADED SAND (SP), with minor roots, fine grained, light brown no roots, light gray/brown

CLAYEY SAND (SC), fine grained, light gray/brown, medium dense

POORLY GRADED SAND WITH CLAY (SP-SC), fine grained, light gray/brown, loose with trace shell, fine grained, tan

CLAYEY SAND (SC), fine grained, tan, medium dense

POORLY GRADED SAND WITH CLAY (SP-SC), fine grained, light gray, medium dense orange and gray

Boring Terminated at 25 Feet

0.3

2.0

4.0

6.0

16.0

19.0

25.0

Hammer Type: AutomaticStratification lines are approximate. In-situ, the transition may be gradual.

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ATTERBERG

LIMITS

LL-PL-PI

LOCATION See Exploration Plan

Latitude: 28.011° Longitude: -82.1224°

G R

AP

H

IC

LO

G

M O

D

EL

LA

YE

R

DEPTH

Advancement Method:

Mud rotary

Abandonment Method:

Boring backfilled with bentonite Surface capped with concrete

Notes:

Project No.: H4185018

Drill Rig: D-25

BORING LOG NO. B-2

Kimley-Horn and Associates IncCLIENT:

Tampa, FL

Driller: C. Hicks

Boring Completed: 09-11-2019

PROJECT: City of Plant City Roadway Improvements

See Exploration and Testing Procedures for a description of field and laboratory procedures used and additional data (If any).

See Supporting Information for explanation of symbols and abbreviations.

Collins Street Plant City, FL

SITE:

Boring Started: 09-11-2019

5463 W Waters Ave, Ste 830 Tampa, FL

While drilling

WATER LEVEL OBSERVATIONS

SA

M

PL

E

TY

PE

SUPPORTING INFORMATION

Soil Parameters Unified Soil Classification System

UNIFIED SOIL CLASSIFICATION SYSTEM

UNIFIED SOI L CLASSI FICATI ON SYSTEM

Criteria for Assigning Group Symbols and Group Names Using Laboratory Tests A Soil Classification

Group Symbol Group Name B

Coarse-Grained Soils:

More than 50% retained on No. 200 sieve

Gravels:

More than 50% of coarse fraction retained on No. 4 sieve

Clean Gravels:

Less than 5% fines C

Cu ³ 4 and 1 £ Cc £ 3 E GW Well-graded gravel F

Cu < 4 and/or [Cc<1 or Cc>3.0] E GP Poorly graded gravel F

Gravels with Fines:

More than 12% fines C

Fines classify as ML or MH GM Silty gravel F, G, H

Fines classify as CL or CH GC Clayey gravel F, G, H

Sands:

50% or more of coarse fraction passes No. 4 sieve

Clean Sands:

Less than 5% fines D

Cu ³ 6 and 1 £ Cc £ 3 E SW Well-graded sand I

Cu < 6 and/or [Cc<1 or Cc>3.0] E SP Poorly graded sand I

Sands with Fines:

More than 12% fines D

Fines classify as ML or MH SM Silty sand G, H, I

Fines classify as CL or CH SC Clayey sand G, H, I

Fine-Grained Soils:

50% or more passes the No. 200 sieve

Silts and Clays:

Liquid limit less than 50

Inorganic:

PI > 7 and plots on or above “A” line J

CL Lean clay K, L, M

PI < 4 or plots below “A” line J ML Silt K, L, M

Organic:

Liquid limit - oven dried

< 0.75 OL Organic clay K, L, M, N

Liquid limit - not dried Organic silt K, L, M, O

Silts and Clays:

Liquid limit 50 or more

Inorganic:

PI plots on or above “A” line CH Fat clay K, L, M

PI plots below “A” line MH Elastic Silt K, L, M

Organic:

Liquid limit - oven dried

< 0.75 OH Organic clay K, L, M, P

Liquid limit - not dried Organic silt K, L, M, Q

Highly organic soils: Primarily organic matter, dark in color, and organic odor PT Peat A Based on the material passing the 3-inch (75-mm) sieve.

B If field sample contained cobbles or boulders, or both, add “with cobbles or boulders, or both” to group name.

C Gravels with 5 to 12% fines require dual symbols: GW-GM well-graded gravel with silt, GW-GC well-graded gravel with clay, GP-GM poorly graded gravel with silt, GP-GC poorly graded gravel with clay.

D Sands with 5 to 12% fines require dual symbols: SW-SM well-graded sand with silt, SW-SC well-graded sand with clay, SP-SM poorly graded sand with silt, SP-SC poorly graded sand with clay.

E Cu = D60/D10 Cc =

DxD

)(D

F If soil contains ³ 15% sand, add “with sand” to group name.

G If fines classify as CL-ML, use dual symbol GC-GM, or SC-SM.

H If fines are organic, add “with organic fines” to group name.

I If soil contains ³ 15% gravel, add “with gravel” to group name.

J If Atterberg limits plot in shaded area, soil is a CL-ML, silty clay.

K If soil contains 15 to 29% plus No. 200, add “with sand” or “with gravel,” whichever is predominant.

L If soil contains ³ 30% plus No. 200 predominantly sand, add

“sandy” to group name.

MIf soil contains ³ 30% plus No. 200, predominantly gravel, add

“gravelly” to group name.

NPI ³ 4 and plots on or above “A” line.

OPI < 4 or plots below “A” line.

P PI plots on or above “A” line.

QPI plots below “A” line.

UNIFIED SOIL CLASSIFICATION SYSTEM