REPORT OF GEOTECHNICAL EXPLORATION TEMPLE TERRACE …

REPORT OF GEOTECHNICAL EXPLORATION

TEMPLE TERRACE LIFT STATION SA TEMPLE TERRACE, FLORIDA

AREHNA PROJECT NO. B-19-018.03-Rev1 March 29, 2019

Revised January 17, 2020

Prepared For: Kimley-Horn and Associates, Inc. 100 2nd Avenue South, Suite 300S St. Petersburg, Florida 33701

Prepared By: AREHNA Engineering, Inc. 5012 West Lemon Street Tampa, Florida 33609

www.arehna.com

5012 West Lemon Street Tampa, Florida 33609 Ph 813.944.3464 │ Fax 813.944.4959

Revised January 17, 2020 March 29, 2019 Mr. W. Wade Wood III, P.E. Kimley-Horn and Associates, Inc. 100 2nd Avenue, Suite 300S St. Petersburg, Florida 33701 E-mail: [email protected]

Subject: Report of Geotechnical Exploration City of Temple Terrace Lift Station SA 6002 E Fowler Avenue Temple Terrace, Florida AREHNA Project B-19-018.03 Rev1 Dear Mr. Wood, AREHNA Engineering, Inc. (AREHNA) is pleased to submit this report of our geotechnical exploration for the proposed project. Services were conducted in general accordance with AREHNA Proposal B.Prop-18-141 dated November 15, 2018. This report presents our understanding of the project, outlines our exploratory procedures, documents the field data obtained and includes our recommendations for the lift station design. AREHNA appreciates the opportunity to have assisted on this project. Should you have any questions with regards to this report, or if we can be of any further assistance, please contact this office. Best Regards, AREHNA ENGINEERING, INC. FLORIDA BOARD OF PROFESSIONAL ENGINEERS CERTIFICATE OF AUTHORIZATION NO. 28410 This item has been digitally signed and sealed by:

Annabella C. Hullen, E.I. Kristina LaCava, P.E. Staff Geotechnical Engineer Geotechnical Engineer Florida Registration 77594 On the date adjacent to the seal.

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

Distribution: 1 – Addressee - Electronic 1 – File

Report of Geotechnical Exploration January 17, 2020 Lift Station SA AREHNA Project B-19-018.03 Rev

ii

TABLE OF CONTENTS

Page

1.0 PROJECT INFORMATION AND SCOPE OF WORK .............................................................. 1 1.1 Site Description and Project Characteristics .................................................................... 1 1.2 Scope of Work ................................................................................................................. 1

2.0 FIELD EXPLORATION AND LABORATORY TESTING ....................................................... 2 2.1 Field Exploration ............................................................................................................. 2 2.2 Laboratory Testing ........................................................................................................... 2

3.0 SUBSURFACE CONDITIONS ...................................................................................................... 3 3.1 USGS Topographic Data ................................................................................................. 3 3.2 USDA Natural Resources Conservation Service Data .................................................... 3 3.3 Subsurface Conditions ..................................................................................................... 3 3.4 Groundwater Conditions .................................................................................................. 3 3.5 Estimated Seasonal High Groundwater Level ................................................................. 4

4.0 DESIGN RECOMMENDATIONS ................................................................................................ 5 4.1 General ............................................................................................................................. 5 4.2 Lift Station Design ........................................................................................................... 5 4.3 Settlement ........................................................................................................................ 5 4.4 Pavement .......................................................................................................................... 6

5.0 GENERAL SITE PREPARATION ............................................................................................... 7 5.1 General ............................................................................................................................. 7 5.2 On-Site Soil Suitability .................................................................................................... 7 5.3 Lift Station Construction ................................................................................................. 7

6.0 BASIS FOR RECOMMENDATIONS ........................................................................................... 8

LIST OF APPENDICES

APPENDIX A

Project Location Map – Figure 1 Boring Location Plan – Figure 2 Boring Profile – Figure 3 USGS Topographic Map – Figure 4 USDA Soil Survey Map – Figure 5

APPENDIX B Laboratory Test Results – Table 1

Field and Laboratory Test Procedures


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1.0 PROJECT INFORMATION AND SCOPE OF WORK

1.1 Site Description and Project Characteristics The project site is located North of E Fowler Avenue and East of N 60th Street in Temple Terrace, Florida as indicated on the Project Location Map, Figure 1 in Appendix A. The project consists of a new 19-foot deep lift station. Structural plans were not available at the time of this report. However, we have assumed that the new design will be similar to the existing wet well. The existing wet well is 12 feet in diameter with a 12 inch thick top slab. We also assumed a 12-inch thick bottom slab and 12-inch thick walls. Based on the dimensions stated previously and assuming the wet well is full of water, a load of 1,200 psf was used in our analysis. 1.2 Scope of Work The purpose of our geotechnical study was to obtain information on the general subsurface conditions at the proposed project site. The subsurface materials encountered were evaluated with respect to the available project characteristics. In this regard, engineering assessments for the following items were formulated:

Identification of the existing ground water levels and estimated normal seasonal high ground water fluctuations.

General site preparation recommendations including the suitability of existing soils for structural fill.

General location and description of potentially deleterious materials encountered in the borings, which may have impact on the proposed construction.

Engineering properties of the soils.

The following services were performed to achieve the above-outlined objectives:

Requested utility location services from Sunshine811. Performed one Standard Penetration Test (SPT) boring to a depth of 45 feet. Samples

were collected, and Standard Penetration Test resistances measured at approximate intervals of two feet for the top ten feet, and at approximate intervals of five feet, thereafter.

Visually classified and stratified soil samples in the laboratory using the Unified Soil Classification System (USCS).

Reported the results of the field exploration and engineering analysis. The results of the subsurface exploration are presented in this report, signed and sealed by a professional engineer specializing in geotechnical engineering.


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2.0 FIELD EXPLORATION AND LABORATORY TESTING

2.1 Field Exploration Our scope included one Standard Penetration Test (SPT) boring extending to a depth of 45 feet below the existing ground surface. The SPT boring was performed with the use of a Drill Rig using Bentonite “Mud” drilling procedures. Samples were collected and Standard Penetration Test resistances were measured at approximate intervals of two feet for the top ten feet and at approximate intervals of five feet thereafter. The soil sampling was performed in general accordance with ASTM Test Designation D-1586, entitled “Penetration Test and Split-Barrel Sampling of Soils.” The upper four feet drilled using manual hand augers to encounter potential utilities. Representative portions of these soil samples were sealed in glass jars, labeled and transferred for appropriate classification. Figure 2 in Appendix A provides a boring location site plan showing the relationship of existing features to the boring. The boring was located in the field by measuring from existing features. 2.2 Laboratory Testing The soil samples were transported to AREHNA’s soil laboratory and were classified by a Geotechnical Engineer using the USCS in general accordance with the ASTM Test Designation D-2488. Laboratory tests included single sieve -200 analysis, Atterberg Limit, and natural moisture content. The test results are presented on Table 1, Appendix B.


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3.0 SUBSURFACE CONDITIONS 3.1 USGS Topographic Data The topographic survey map published by the United States Geological Survey was reviewed for ground surface features at the proposed project location (Figure 4, Appendix A). Based on this review, the natural ground surface elevations at the project site is approximately +30 to +35 feet. 3.2 USDA Natural Resources Conservation Service Data The United States Department of Agriculture (USDA) Natural Resources Conservation Service (NRCS) survey for Hillsborough County indicates that the soils at the project site consist of the following soil unit:

Soil Unit Number

Soil Name Depth Below Natural Grade

to High Water Table (feet)

53 Tavares-Millhopper complex, 0 to 5 percent

slopes 3.5 - 6

The soil survey also indicates that the average annual precipitation is 45 to 53 inches. The soils encountered in our borings are consistent with the soil unit described above. The USDA Soil Survey map for the project site is attached as Figure 5. 3.3 Subsurface Conditions A pictorial representation of the subsurface conditions encountered in the boring is shown on the Boring Profiles, Figure 3 in Appendix A. This profile and the following soil conditions highlight the general subsurface stratification. Soil conditions may vary between, and away from, boring locations. The SPT boring generally encountered loose to medium dense fine sands (SP, SP-SM, SM, SC) from the ground surface to a depth of approximately 28 feet. Standard Penetration Test Resistances (N-values) ranged between 4 and 21 blows per foot. Beneath the sandy soils a layer of soft to stiff clay (CH) was encountered to a depth of 38 feet below the existing ground surface; N-values of 4 and 10 blows per foot were recorded. The boring terminated at a depth of 45 feet in limestone. The limestone had N-Values of 7 and 26 blows per foot indicating soft to medium hard consistency. 3.4 Groundwater Conditions The groundwater level was encountered at a depth of 5 feet below the existing ground surface in the SPT boring performed. Fluctuation in ground water levels should be expected due to seasonal climatic changes, construction activity, rainfall variations, surface water runoff, and other site-specific factors. Since ground


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water level variations are anticipated, design drawings and specifications should accommodate such possibilities and construction planning should assume that variations will occur. 3.5 Estimated Seasonal High Groundwater Level Based on the mapping performed by the USDA, the seasonal high water table is 3.5 to 6 feet below natural grades. Based on the soil information obtained from the site, and our experience in the area, we estimate that the seasonal high ground water level will be encountered at a depth of approximately 3.5 feet below the existing ground surface.


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4.0 DESIGN RECOMMENDATIONS

4.1 General Our geotechnical evaluation is based upon the field data obtained during this geotechnical exploration and previous experience in the project vicinity. If the final structure location is significantly different from those described or if the subsurface conditions during construction are different from those revealed by our boring, we should be notified immediately so that we might review our recommendations presented in this report. After complete removal of all existing topsoil, roots, debris, and other deleterious materials from beneath the lift station and to a minimum of five feet beyond the development perimeter, the area should be sheeted. Our recommended site preparation is presented in Section 6.0, General Site Preparation. 4.2 Lift Station Design Based on the provided as-built, the existing lift station is supported on 12-inch concrete filled steel pipe piles. Four No. 5 bars were embedded approximately 1.7 feet into each pile and were connected to the bottom slab of the lift station. It should be noted that a building was constructed on top of the existing wet well. Our previous analysis of the soil conditions in the SPT boring revealed excessive long-term settlement could occur after constructing the proposed lift station if built on shallow foundations. Since our original report, dated March 29, 2019, the proposed wet well was shortened to 19 feet and AREHNA was made aware that there is an existing odor control system currently occupying the area where the proposed wet well will be going. The odor control system is on a 23.7 by 39.9 square feet slab with a total weight of 31,600 pounds. Therefore, the long-term settlement significantly decreases due to the shortened wet well and existing odor control system present. We anticipate the proposed lift station will be installed in a sheeted excavation with a concrete plug placed at the bottom of the lift station structure. The lift station should be designed to resist hydrostatic lateral and uplift pressure and earth pressures. An allowable bearing pressure of 2,000 psf should be available, using the site preparation recommended in Section 6.0, General Site Preparation. The lift station area should be sheeted to properly retain the soil and groundwater. 4.3 Settlement The immediate settlement of the lift station supported on sandy soils should occur rapidly during construction as dead loads are imposed on the bottom slab of the lift station. Due the existing loading conditions imposed by the odor control system; the long-term consolidation settlement of the proposed wet well will be minimized. Provided that the recommended subsurface preparation operations are properly performed, the total immediate settlement and long term settlement of the lift station should be approximately ½ inch, with differential settlements on the order of 50 percent of the total settlements.


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4.4 Pavement AREHNA was informed that a concrete drive will be constructed adjacent to the proposed wet well. It is recommended that prior to the construction of the concrete drive, that the subgrade soils supporting rigid pavement be compacted to 98 percent of the Modified Proctor maximum dry density (ASTM D-1557) to a minimum depth of 12 inches. If the wet well is planned to be installed prior to the concrete drive, care should be taken during compaction. Compaction can be achieved by using a walk behind vibratory roller with a 12-inch diameter double drum and a static weight of at least 900 pounds. The vibratory mechanism should be turned off when compacting directly adjacent to the proposed wet well. We suggest that concrete with an unconfined compressive strength of at least 4,000 lb/in2 be placed over properly compacted subgrade soils. We recommend that a minimum thickness of 6 inches be utilized. The maximum spacing between control joints should be limited to 12 feet.


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5.0 GENERAL SITE PREPARATION

5.1 General Prior to constructing the lift station, the complete removal of all existing topsoil, roots, debris, and other deleterious materials from beneath the lift station and to a minimum of five feet beyond the development perimeter should be performed. The lift station area should then be sheeted. 5.2 On-Site Soil Suitability The boring indicates that fine sand classified as SP and SP-SM was encountered to a depth of approximately 18 feet and is suitable for use as backfill. Suitable backfill materials should consist of fine to medium sand with less than 12 percent passing the No. 200 sieve and be free of rubble, organics, clay, debris and other unsuitable material. Any off-site materials used as fill should be approved by AREHNA prior to acquisition. 5.3 Lift Station Construction We recommend that steel sheet piles be placed. After excavation inside the sheets to the desired depth without dewatering, tremie methods should be used to form a concrete plug that will resist uplift pressures. After the concrete tremie plug has hardened, the inside of the lift station should be dewatered and the required lift station equipment installed. We have included soil parameters for use in below grade construction. The table below presents recommended lateral earth pressure parameters for use in design.

Recommended Soil Parameters

Boring No.

Depth range, ft

Average SPT “N”

Value

Unified Soil Classification

Soil Unit Weight (pcf) Soil Angle of Internal

Friction (degrees)

Soil Cohesion/ Unit Skin Friction

(psf)

Soil Earth Pressure Coefficients

Total Submerged Active (Ka)

At-rest (Ko)

Passive (Kp)

B-01

0 – 28 10 SP, SP-SM, SM,

SC 105 42.6 30 - 0.33 3.0 0.45

28 – 38 7 CH 110 47.6 - 875 1.0 1.0 1.0

38 – 45 17 WLS, LS 125 62.6 - 2,125 1.0 1.0 1.0


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6.0 BASIS FOR RECOMMENDATIONS

The analysis and recommendations submitted in this report are based upon the data obtained from the soil borings performed at the locations indicated. Regardless of the thoroughness of a geotechnical exploration, there is always a possibility that conditions between borings will be different from those at specific boring locations and that conditions will not be as anticipated by the designers or contractors. In addition, the construction process itself may alter soil conditions. AREHNA is not responsible for the conclusions, opinions or recommendations made by others based on the data presented in this report.

APPENDIX A

Project Location Map – Figure 1

Boring Location Plan – Figure 2

Boring Profile – Figure 3

USGS Topographic Map – Figure 4

USDA Soil Survey Map - Figure 5

FIG NO.

PROJECT LOCATION MAP

PROJECT NO.

Engineering,Inc.AREHNA5012 West Lemon Street, Tampa, FL 33609Phone 813.944.3464 Fax 813.944.4959

Certificate of Authorization No. 28410

PROJECT NAME

1

DATE

B-19-018.0303/2019

CITY OF TEMPLE TERRACE LIFT STATION SA

TEMPLE TERRACE, FLORIDA

SITE LOCATION

AutoCAD SHX Text

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B-01

DATE

03/2019

APPROVED

REVISIONS

ASC

BRH

BRH

DATENAME

SUPERVISED BY:

CHECKED BY:

DRAWN BY:

DESIGNED BY:

FIGURE NO.PROJECT NO.

03/2019

03/2019


PROJECT NAME



PREPARED BY:

NO. DESCRIPTIONS


2B-19-018.03

BORING LOCATION PLAN

APPROXIMATE PLAN SCALE

0 100'

Approximate Location of Standard Penetration

Test (SPT) Boring

LEGEND

E FOWLER AVE

N 60T

H S

T

B-X

Kristina LaCava, P.E.

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LEGEND

Groundwater Level at Time of Drilling

SAFETY HAMMER

MEDIUM DENSE

GRANULAR MATERIALS-

SPT N-VALUE

GREATER THAN 24

LESS THAN 3

(BLOWS/FT.)

SPT N-VALUE

(BLOWS/FT.)

GREATER THAN 40

3 to 8

16 to 30

8 to 15

LESS THAN 1

3 to 6

1 to 3

6 to 12

24 to 40

8 to 24

12 to 24

CONSISTENCY

FIRM

SOFT

VERY STIFF

STIFF

SILTS AND CLAYS

VERY SOFT

4 to 8

2 to 4

RELATIVE DENSITY

LOOSE

DENSE

VERY DENSE

(BLOWS/FT.)

SPT N-VALUE

(BLOWS/FT.)

30 to 50

10 to 30

4 to 10

SPT N-VALUE

LESS THAN 2

VERY LOOSE

HARD GREATER THAN 30

LESS THAN 4

GREATER THAN 50

LEGEND

Groundwater Level at Time of Drilling

AUTOMATIC HAMMER

GRANULAR MATERIALS-

(BLOWS/FT.)

SPT N-VALUE

RELATIVE DENSITY (BLOWS/FT.)

SPT N-VALUE

Soil Profile Notes:

1. The profiles depicted are of a generalized nature to highlight the major subsurface

stratification features and material characteristics. The soil profiles include soil

description, stratifications and penetration resistances. The stratifications shown on the

boring profiles represent the conditions only at the actual boring location. Variations may

occur and should be expected between boring locations. The stratifications represent the

approximate boundary between subsurface materials and the actual transition may be

gradual.

2. Groundwater levels generally fluctuate during periods of prolonged drought and extended

rainfall and may be affected by man-made influences. In addition, a seasonal effect will

also occur in which higher groundwater levels or temporary perched conditions are

normally recorded in rainy seasons.

3. The Boring Locations Presented are Approximate and Based on Hand Held GPS with an

Accuracy of +/- 10 Feet.

N SPT N-Value In Blows/Foot For 12 Inches Of

Penetration Utilizing Automatic Hammer

(unless otherwise noted)

Silty Sand (SM)

Fine Sand (SP/SP-SM)

MEDIUM

HARD

VERY HARD

SOFT

51 to 50/3"

20 to 50

LESS THAN 20

GREATER THAN 50/3"

SPT N-VALUE

(BLOWS/FT.)CONSISTENCY (BLOWS/FT.)

SPT N-VALUE

CONSISTENCY

LIMESTONE

(BLOWS/FT.)

SPT N-VALUE

42 to 50/6"

17 to 41

GREATER THAN 50/6"

LESS THAN 17

Clayey Sand (SC)

Clay (CH)

SP Unified Soil Classification System (ASTM D 2488)

Group Symbol As Determined By Visual Review

And/Or Laboratory Testing

N

8

21

HA

HA

7

B-01

N

3-8-19

25

20

0

5

DE

PT

H IN

F

EE

T

10

15

20

10

4

LIGHT BROWN FINE SAND WITHTRACE CEMENTED SAND (SP)

LIGHT BROWN TO LIGHT GRAYFINE SAND (SP)

LIGHT GRAY SILTY FINE SAND (SM)

30

35

4

7

LIGHT GRAY FINE SAND WITHSILT (SP-SM)

40

10

LIGHT GRAY CLAY WITH TRACELIMESTONE FRAGMENTS (CH)

Boring Terminated

at 45 Feet

Latitude: 28.0548353

Longitude: -82.3892339

26

45

LIMESTONE

LIGHT GRAY CLAYEY FINE SAND WITHTRACE LIMESTONE FRAGMENTS (SC)

WEATHERED LIMESTONE

Limestone (LS)

Highly Weathered

Limestone (HWLS)

25

0

5

DE

PT

H IN

F

EE

T

10

15

20

30

35

40

45

HA Hand Augered To Avoid Utility Conflicts

and Safety Reasons

BORING PROFILE

DATE

03/2019

APPROVED

REVISIONS

ASC

BRH

BRH

DATENAME

SUPERVISED BY:

CHECKED BY:

DRAWN BY:

DESIGNED BY:

FIGURE NO.PROJECT NO.

03/2019

03/2019


BORING PROFILE



PREPARED BY:

NO. DESCRIPTIONS


3B-19-018.03

Kristina LaCava, P.E.

NMC=44

-200=59

LL=67

PL=21

PI=46

Fines Passing The #200 Standard Sieve (%)

Liquid Limit (%)

Plasticity Index (%)

Natural Moisture Content (%)

Plasticity Limits (%)

200

LL

PI

NMC

PL

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0 N.T.S.

FIG NO.

USGS TOPOGRAPHIC MAP

PROJECT NO.

Engineering,Inc.AREHNA


PROJECT NAME

4

DATE

5012 West Lemon Street, Tampa, FL 33609Phone 813.944.3464 Fax 813.944.4959

SITE LOCATION

B-19-018.0303/2019



AutoCAD SHX Text

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FIG NO.

USDA SOIL SURVEY MAP

PROJECT NO.



PROJECT NAMEDATE

SOIL MAPPING UNITS

53—Tavares-Millhopper complex, 0 to 5 percent slopes


0 N.T.S.

SITE LOCATION

53

B-19-018.0303/2019



5

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APPENDIX B

Summary of Laboratory Test Results – Table 1 Field and Laboratory Procedures

TABLE 1 SUMMARY OF LABORATORY DATA

Lift Station SA

Temple Terrace, Florida AREHNA Project B-19-018.03

Boring No. Sample Depth

(feet) Percent Moisture

Content Percent Finer (-200 sieve)

Liquid Limit

Plastic Limit

Plasticity Index

B – 01 28.5 – 30 44 59 67 21 46

FIELD PROCEDURES Standard Penetration Test (SPT) Borings The SPT borings are performed in general accordance with ASTM D-1586, "Penetration Test and Split-Barrel Sampling of Soils." A rotary drilling process is used and bentonite drilling fluid is circulated in the boreholes to stabilize the sides and flush the cuttings. At regular intervals, the drilling tools are removed and soil samples are obtained with a standard 2-feet long, 2-inch diameter split-tube sampler. The sampler is first seated 6 inches and then driven an additional foot with blows of a 140-pound hammer falling under its own weight a distance of 30 inches. The number of hammer blows required to drive the sampler the final foot is designated the "Penetration Resistance." The penetration resistance, when properly interpreted, is an index to the soil strength and density.

LABORATORY PROCEDURES Water Content The water content is the ratio, expressed as a percentage, of the weight of water in a given mass of soil to the weight of the solid particles. This test is conducted in general accordance with FM 1-T265. Atterberg Limits (Plasticity) A soil's Plasticity Index (PI) is the numerical difference between the Liquid Limit (LL) and the Plastic limit (PL). The LL is the moisture content at which the soil will flow as a heavy viscous fluid and is determined in general accordance with ASTM D-4318. The PL is the moisture content at which the soil begins to crumble when rolled into a small thread and is also determined in general accordance with FM 1-T 90. Fines Content In this test, the sample is dried and then washed over a No. 200 mesh sieve. The percentage of soil by weight passing the sieve is the percentage of fines or portion of the sample in the silt and clay size range. This test is conducted in general accordance with ASTM D-1140.

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