22-E3.2 Geotechnical Report.pdf

5911 Breckenridge Parkway, Suite G, Tampa, Florida 33610 Phone: (813) 623-3399, Fax: (813) 623-6636 www.mc2engineers.com

MC Squared, LLC

Geotechnical Engineering Services Report

Fort King Sidewalk LAP – Box Culvert Extension

Dade City, Florida

Prepared for: Ayres Associates, Inc.

8875 Hidden River Parkway, Suite 200

Tampa, Florida 33637

Prepared by: MC Squared, LLC

5911 Breckenridge Parkway, Suite G

Tampa, Florida 33610

MC2 Project No. T022403.017_G

November 1, 2024

5911 Breckenridge Parkway, Suite G, Tampa, Florida 33610 Phone: (813) 623-3399, Fax: (813) 623-6636 www.mc2engineers.com

November 1, 2024

Mr. Jeffrey Siewert, P.E.

Ayres Associates, Inc.

8875 Hidden River Parkway, Suite 200

Tampa, Florida 33637

Subject: Geotechnical Engineering Services Report

Fort King Sidewalk LAP – Box Culvert Widening

MC2 Project Number T022403.017_G

Dear Mr. Siewert:

MC Squared LLC (MC2) has completed our Geotechnical Engineering Services associated with the proposed box culvert widening along Fort King Road, south of Poinsettia Avenue, in Dade City, Florida. This report presents our understanding of the project, outlines our exploratory procedures, documents the field data obtained, and includes our recommendations for site preparation and foundation design.

We trust that this report will assist you with design development and construction of the proposed project. We appreciate the opportunity to be of service on this project. Should you have any questions, please do not hesitate to contact us.

Respectfully submitted, MC Squared, LLC

Kristina LaCava, P.E. Jeffery C. Sizemore, P.E.

Geotechnical Project Manager Chief Engineer

Florida PE License No. 77594

Fort King Sidewalk LAP – Box Culvert

MC2 Proposal No. T022403.017_G i

TABLE OF CONTENTS

1 PROJECT INFORMATION

1.1 Project Authorization

1.2 Project Description

1.3 Scope of Services

2 FIELD EXPLORATION & LABORATORY TESTING

2.1 Field Exploration

2.2 Laboratory Testing

3 GENERAL SUBSURFACE CONDITIONS

3.1 Site Features

3.2 USGS Topographic Map

3.3 Pasco County Soil Survey

3.4 Subsurface Conditions

3.5 Groundwater Information

4 EVALUATIONS AND RECOMMENDATIONS

4.1 General

4.2 Excavation

4.3 Dewatering

4.4 Box Culvert - Mat Foundation and Subsoil Compaction

4.5 End Walls - Spread Footings and Subsoil Compaction

4.6 Backfill

4.7 Uplift Resistance

4.8 Lateral Earth Pressure on Shoring and Bracing

4.9 Lateral Earth Pressure on the Box Culvert

5 REPORT LIMITATIONS

Appendix

Project Location Map – Sheet 1

USGS Topographic Map - Sheet 2

USDA Soil Survey Map – Sheet 3

Boring Location Map – Sheet 4

Soil Boring Profile – Sheet 5

Summary of Laboratory Test Results – Table 1

Summary of Corrosion Test Results – Table 2

Summary of Soil Parameters – Table 3

Test Procedures

MC2 Proposal No. T022403.017_G

1 PROJECT INFORMATION

1.1 PROJECT AUTHORIZATION

The project was authorized by Task Order No. 26 entered between Ayres Associates, Inc. (Ayres) and MC Squared, LLC (MC2) on August 2, 2024. Our geotechnical engineering services were performed in general accordance with MC2 Proposal T022403.017_G dated February 16, 2024, and the Master Subconsultant Agreement dated December 4, 2008, between Ayres and MC2.

1.2 PROJECT DESCRIPTION

Project information was provided by Mr. Jeffrey Siewert of Ayres through e-mail correspondence dated February 16, 2024. Based on our understanding, Pasco County is planning a sidewalk, drainage improvements, and a culvert extension along Fort King Road from Hester Road to

Coleman Avenue in Dade City, Florida. An existing culvert currently crosses under Fort King Road between Dixie Avenue and Poinsettia Avenue, as shown on the Project Location Map, Sheet 1 in the Appendix. As a part of the improvements, it is proposed to extend the existing 60-foot-long culvert approximately 12 feet on the east side of Fort King Road to accommodate the new sidewalk.

The existing culvert is a double barrel concrete pre-cast structure. The cross-sectional dimensions of the box culvert will remain the same at 6 feet wide and 5 feet high per barrel. It is assumed that thickness on the top and bottom of the culvert is 1.5 feet, and the thickness of the side(s)/between the barrels is ½ foot. Based on correspondence with Ayres, the bottom of the culvert is buried approximately 2 feet from the existing ground. Therefore, we assume the invert of the new culvert will be no more than 12 feet below the top of existing pavement. Ayres has requested our geotechnical engineering services in support of the design and construction of box culvert.

If any of this project’s description is incorrect or has changed, please inform MC2 so that we may amend, if appropriate, the information presented in this report.

1.3 SCOPE OF SERVICES

Our scope of services consisted of the following:

1. Conducted a visual reconnaissance of the project site. Reviewed the USDA Soil Survey for Pasco County and the USGS Topographic map of the project site.

2. Cleared utilities in the vicinity of the project site through Sunshine811.

3. Performed two (2) Standard Penetration Test (SPT) borings to depths of 40 and 50 feet north and south of the existing box culvert. The borings were performed as close as possible to the culvert extension. The SPT borings were performed in general accordance with ASTM D1586. The SPT borings were initiated with a hand auger in the uppermost 4 feet to avoid potentially unmarked shallow utilities. The SPT borings were then advanced continuously to a depth of 10 feet, then at five-foot intervals

MC2 Proposal No. T022403.017_G thereafter. Split spoon samples were collected at each SPT interval. Representative soil samples obtained from the SPT borings were sealed in clean, airtight containers and transported to our Tampa, Florida office for further classification.

4. Performed one (1) hand auger boring extending to a depth of 5 feet below the existing ground surface just east of the existing culvert, within the creek crossing.

5. Measured the depth to groundwater at the boring locations, where encountered.

6. Upon completion of the drilling operations, the boreholes were backfilled with bentonite slurry. Excess cuttings were disposed of in the boreholes. Any remaining drill cuttings and drilling fluid was spread on the ground surface near each borehole.

7. All recovered soil samples were visually examined in the laboratory. Lab tests were conducted on selected representative soil samples using the Unified Soil Classification

System (USCS). The USCS classification was determined through various laboratory testing including percent passing the No. 200 sieve, natural moisture content, and organic content tests.

8. Corrosion series tests were conducted on one (1) composite soil sample from the SPT borings. A water sample was not obtained due to no water being present in the creek at the time of our exploration.

MC2 presents the following data and recommendations in our report:

1. General assessment of subsurface conditions in the project area based on our experience, study of USDA soil survey data, and information from SPT borings.

2. Summary of field and laboratory data generated.

3. General location and description of potentially deleterious materials encountered in the borings, which may interfere with the proposed construction or performance, including existing fills or surficial organics.

4. Estimations of the Seasonal High Water Table (SHWT) at the locations of SPT borings.

5. Geotechnical engineering recommendations including soil bearing capacity, estimated settlement, soil parameters, and site preparations to assist with the foundation design of the culvert extension.

The scope of our services did not include an environmental assessment for determining the presence or absence of wetlands or hazardous or toxic materials in the soil, bedrock, groundwater, or air, on or below or around the project site. Any statements in this report, or on the boring profiles regarding odors, colors, unusual or suspicious items or conditions, are strictly for the information of our client. In addition, our scope of services did not include an evaluation of sinkholes or sinkhole activity, and none were performed.

Boring coordinates presented in this report are approximate and for information purposes only.

MC2 Proposal No. T022403.017_G

Coordinates are estimated from Google Earth (WGS 1984 coordinate system). A topographic survey must be performed by others to obtain accurate coordinate and elevation data.

2 FIELD EXPLORATION & LABORATORY TESTING

2.1 FIELD EXPLORATION

Our field exploration program consisted of performing two (2) Standard Penetration Test (SPT) borings extending to depths of 40 and 50 feet below the existing ground surface (bgs) and one

(1) hand auger (HA) extending to a depth of 5 feet bgs at the project site. The SPT and HA borings were performed on August 16, 2024, and were monitored and documented by a qualified staff geotechnical engineer of MC2. The field exploration was overseen by a Florida-licensed professional geotechnical engineer of MC2.

The SPT borings were performed with the use of a Power Drill Rig using Bentonite “Mud” drilling procedures. Samples were collected and Standard Penetration Test resistances were measured continuously for the upper 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 was manually hand augered to avoid potential unmarked underground utilities. SPT borings were backfilled with soil cuttings and bentonite chips after completion of the boring.

The HA boring was completed at the site in general accordance with ASTM D1452 (Standard

Practice for Soil Exploration and Sampling by Auger Borings) using a 3 ¼-in. diameter auger bucket. Samples were collected at every soil change, classified, and logged in the field. The HA boring was backfilled with soil cutting after completion of the boring.

Soil samples, recovered during the field exploration program, were placed into air-tight glass jars labeled with the project number, boring number, sample number and date drilled and delivered to our Tampa, Florida office to confirm field classification and perform laboratory testing, as required. All soil samples collected will be retained in house for 60 days from the date of release of this report and will subsequently be discarded without further notice unless requested otherwise in writing.

Groundwater, if encountered, was measured during the advancement of the boring and prior to the introduction of drilling slurry. Once slurry is added, an accurate groundwater level is difficult to measure at the time of drilling. The groundwater condition encountered in our borings is presented in Section 3.5 herein.

The location of the borings are shown on the attached Boring Location Map, Sheet 4 in the

Appendix. They were located in the field by Global Positioning System (GPS) using a hand-held

WAAS enabled GPS unit and coordinates obtained from Google Earth Pro. If a more precise location of the borings is desired, then it is recommended that a registered land surveyor be employed to locate the borings on site. GPS coordinates and approximate elevations of the boring locations are provided on the Soil Boring Profile, Sheet 5 in the Appendix.

MC2 Proposal No. T022403.017_G

2.2 LABORATORY TESTING

The soil samples were visually classified by one of our geotechnical engineers. Representative soil samples were selected to be tested in the laboratory to assist in the classification and determination of engineering characteristics of the soils based on their mechanical and physical behavior.

Laboratory testing was accomplished in general accordance with applicable ASTM and FDOT standards. Laboratory tests completed on soil samples retrieved for this project were as follows:

• Five (5) moisture content determinations (ASTM D-2216)

• Five (5) percent passing the No. 200 US standard sieve tests (ASTM D-1140)

• One (1) organic content determination (ASTM D-2974)

• Visual classification in general accordance with applicable procedures (ASTM D-2488).

Results of the laboratory tests completed on soil samples collected from this project site are provided on Table 1 in the Appendix.

In addition to the lab soil testing to determine their index properties, corrosion series tests were conducted as per FDOT test designations FM 5-550, FM 5-551, FM 5-552, and FM 5-553. These tests were performed on a composite soil sample obtained from the HA boring performed within the creek. It should be noted that a water sample could not be obtained at the time of our field exploration due to there being no water within the creek. Corrosion tests measured pH, resistivity, sulfate content, and chloride content. Results of the corrosion series test are presented on Table 2 in the Appendix.

Based on the corrosion series test results and Section 1.3.2 of the FDOT Structures Design

Guidelines, dated January 2024, the subsurface conditions for soil should be classified as slightly aggressive for steel and concrete. We recommend using the applicable provisions in the FDOT

Structures Design Guidelines and FDOT Standard Specifications to ensure corrosion protection and selection of appropriate grades of steel and concrete.

3 GENERAL SUBSURFACE CONDITIONS

3.1 SITE FEATURES

The existing box culvert is located on Fort King Road, approximately 40 feet south of Poinsettia

Avenue in Dade City, Florida. Fort King Road serves as a two-way, two-lane undivided paved road and is open to vehicular traffic. The project site consists of the existing box culvert area and is surrounded by wooded areas, commercial businesses, and residential areas. The culvert crosses over a creek, which at the time of our investigation did not have any water.

The approximate project location is shown on an aerial photograph, obtained from Google Earth

Pro, presented as Project Location Map, Sheet 1 in the Appendix.

MC2 Proposal No. T022403.017_G

3.2 USGS TOPOGRAPHIC MAP

Based on our review of the Dade City, Florida USGS Topographic map, the ground surface elevation at the site is approximately +80 feet NAVD88. A portion of the USGS Topographic

Quadrangle Map is provided on Sheet 2 in the Appendix for information and reference.

3.3 PASCO COUNTY SOIL SURVEY

The USDA Soil Conservation Service (SCS) Soil Survey for Pasco County, Florida, was obtained and reviewed for general information on the shallow soils existing within the project limits. The survey data is Version 22 dated September 6, 2023, with aerial images taken between January 6, 2022, and January 30, 2022. The USDA SCS Soil Survey outlines approximate areas dominated by a shallow soil type. Small areas of other soils may occur within the mapping unit. The project site is located within one (1) mapping unit, Tavares sand, 0 to 5 percent slopes (6).

Tavares sand, 0 to 5 percent slopes (6) has a parent material of Eolian or sandy marine deposits and a typical profile of fine sand from 0 to 80 inches below the natural ground surface. The material is moderately well drained and has a moderately high to very high capacity to transmit water. The depth to the groundwater table is about 3.5 to 6 feet below the natural ground surface.

The USDA Soil Survey is not necessarily an exact representation of the soils on the site. The mapping is based on interpretation of aerial maps with scattered shallow borings for confirmation. Accordingly, borders between mapping units are approximate and the change may be transitional. Variations may also occur from the typical stratigraphy, and small areas of other similar and dissimilar soils may occur within the soil-mapping unit. As such, there may be differences between the mapped description and the boring descriptions obtained for this report. Development/urbanization can also cause variations in the typical stratigraphy.

The survey is, however, a good basis for evaluating the shallow soil conditions of the area. A portion of the USDA Soil Survey Map illustrating the soil mapping units for the project area can be found on Sheet 3 in the Appendix.

3.4 SUBSURFACE CONDITIONS

The descriptions of the subsurface conditions discussed herein are of a generalized nature and highlight the major stratification features and material characteristics. The Soil Boring Profile, Sheet

5 included in the Appendix should be reviewed for specific information for the individual boring location. The soil boring profiles include soil description, stratification, penetration resistances and laboratory test results. The stratifications shown on the boring profiles represent the conditions only at the actual boring locations. Stratifications can be gradual, and variations may occur and should be expected.

In general, the subsurface soils encountered in boring B-01 consisted of loose to medium dense poorly graded fine SAND (SP) to clayey fine sand (SC) from the existing ground surface to the termination depth of 40 feet. N-values ranged between 5 to 27 blows per foot (bpf).

The subsurface soils encountered in boring B-02 generally consisted of loose to medium dense poorly graded sands of various fines (SP, SP-SM, and SC) from the existing ground surface to the termination depth of 50 feet. N-values for the sandy soils ranged between 5 and 24 bpf. A 10-foot interbedded layer of firm to stiff high plasticity clay (CH) was penetrated from 33 to 43 feet.

N-values of 7 and 10 bpf were recorded for the clay soils.

In general, the subsurface soils encountered in the hand auger boring consisted of poorly graded organic fine sand with silt (SP-SM) from the existing ground surface to a depth of 6 inches. The hand auger boring then penetrated poorly graded fine sand with silt (SP-SM) to fine sand (SP) to the termination depth of 5 feet. The upper 6-inches encountered in the hand auger boring appears to be sediment soils.

3.5 GROUNDWATER INFORMATION

Groundwater was not apparent in the upper 10 feet of the SPT borings performed. This is not an indication that groundwater was not encountered within the vertical reaches of the borehole, but rather that groundwater was not encountered prior to the introduction of drilling slurry which prevented an accurate measurement of the groundwater depth. The groundwater depth for the borings is labeled GNA (groundwater not apparent) on the soil profiles presented on the

Soil Boring Profile sheet in the Appendix. Further, the groundwater was not encountered within the explored depth of the hand auger boring.

Based on the information collected from the borings performed and from the USDA soil survey, we estimate the SHWT level to be greater than 10 feet below the existing ground surface at the locations of the SPT borings, and at an approximate depth of 3 feet below the existing ground surface at the location of the HA boring performed in the creek. This estimate is based on the color and texture of the soil samples collected, and the USDA Soil Survey information for the project site. It should be noted that flood stage water levels and creek water levels are different from the SHWT.

In general, groundwater levels tend to fluctuate during periods of prolonged drought and extended rainfall and are affected by man-made influences such as drainage conveyance systems. In addition, a seasonal effect will occur in which higher groundwater levels are normally recorded in rainy seasons. Fluctuation of the groundwater levels should be anticipated, and we recommend that the Contractor determine the actual groundwater levels at the time of the construction to determine groundwater impact on the construction procedure.

4 EVALUATIONS AND RECOMMENDATIONS

4.1 GENERAL

The results of our exploration indicate that, with proper site preparation as recommended in this report, the existing soils are suitable for supporting the proposed culvert extension. However, it is recommended that the culvert extension be supported on a bedding layer consisting of at least

12-inches of No. 57 Stone, or equivalent.

The following are our recommendations for overall site preparation and foundation support which we feel are best suited for the proposed construction and existing soil conditions. The recommendations are made as a guide for the design engineer, parts of which should be incorporated into the project’s specifications.

Section 4 presents our recommendations for the design, site preparation, and construction of this box culvert extension project. The geotechnical properties (soil parameters), which we prepared in due consideration of the existing subsurface soil conditions, are presented on Table

3 in the Appendix. The recommendations are made as a guide for the design engineer, and for incorporation into the project’s specifications, as needed.

4.2 EXCAVATION

Based on the conditions encountered during the field exploration, we anticipate that most of the sandy soils that were encountered in the SPT borings, can be excavated with standard earth moving equipment (i.e., front-end loaders and backhoes).

It is recommended that the soils below the bottom of the foundation elevations be over-excavated approximately 12-inches. The over-excavated areas should then be backfilled with No.

57 Stone or equivalent, ultimately supporting the culvert extension on a bedding layer.

The actual methods of excavation should be determined by the Contractor; however, the excavation should be safely braced to prevent injury to personnel or damage to equipment.

4.3 DEWATERING

The groundwater table was not apparent in the upper 10 feet of the SPT borings performed and not encountered within the explored depth of the hand auger boring. However, depending on the time of construction the control of groundwater may be required to achieve the necessary depths of excavation and subsequent backfilling/compaction requirements presented in the following sections. The actual method(s) of dewatering should be determined by the contractor;

however, regardless of the method(s) used, water levels should be maintained at least 1-foot below the foundation bearing elevation. The dewatering should be accomplished in advance of the excavation.

Caution must be exercised by the Contractor to prevent unnecessary dewatering for prolonged periods of time in order to prevent ground settlement and/or settlement of any nearby structures, utilities, or roadway as a result of the added overburden pressure resulting from lowering of the groundwater table. All structures and/or utilities located adjacent to the proposed excavation shall be surveyed as well as monitored for settlements during dewatering operations in accordance with FDOT Standard Specifications.

MC2 Proposal No. T022403.017_G

4.4 BOX CULVERT - MAT FOUNDATION AND SUBSOIL COMPACTION

After the excavation and prior to placing the bedding stone, the existing sandy soils should be compacted to at least 95 percent of the Modified Proctor maximum dry density (ASTM D1557).

The bedding stone should be compacted until the area is unyielding. A geotechnical technician working under the direction of the Geotechnical Engineer, should be present at the time of compaction.

Based on the existing soil conditions, and assuming the above outlined excavation and compaction criteria are implemented, a factored bearing resistance of up to 5,800 pounds per square foot (psf) across the bottom of foundation should result in total settlement of less than

1-inch, and differential settlement up to ½-inch. A modulus of subgrade reaction of 25 pounds per cubic inch (pci) may be used for box culvert design. A minimum cover of 12 inches should be maintained above the bottom of the mat foundation to the top of adjacent finished grades on creek bed.

4.5 END WALLS - SPREAD FOOTINGS AND SUBSOIL COMPACTION

After the excavation and prior to placing the bedding stone, the existing sandy soils should be compacted to at least 95 percent of the Modified Proctor maximum dry density (ASTM D1557).

The bedding stone should be compacted until the area is unyielding. A geotechnical technician working under the direction of the Geotechnical Engineer, should be present at the time of compaction.

Based on the existing soil conditions, and assuming the above outlined excavation and compaction criteria are implemented, a factored bearing resistance of up to 2,500 psf may be across the bottom of foundation should result in total settlement within tolerable limits (i.e., 1 inch or less). The spread footings of culvert end walls should be 3-ft wide at the minimum. A minimum cover of 12 inches should be maintained above the bottom of the foundations to the top of adjacent finished grades. Foundations may be designed using 0.4 as the coefficient of sliding along the base.

4.6 BACKFILL

As a general guide to aid the contractor, we recommend using fill with less than 12 percent by dry weight of material passing the U.S. Standard No. 200 sieve size. Soils with more than 12 percent passing the No. 200 sieve will be more difficult to compact due to their inherent nature to retain soil moisture. Based on the soil samples obtained during our subsurface investigation, the fine SAND to fine SAND with silt (SP and SP-SM) appear to be suitable for use as structural backfill for box culvert and end wall structures. In addition, any soil with an organic content greater than 5% is unsuitable as backfill. We note that material removed from below the groundwater table will be wet and require time to dry sufficiently.

The final backfill above and around the box culverts must extend all the way to the trench walls and should be placed in loose lifts not exceeding 12 inches. Each lift should be compacted to at least 95 percent of the maximum dry density, as determined by the modified Proctor (ASTM

MC2 Proposal No. T022403.017_G

D1557). Care should be taken not to damage the culvert by compacting directly above the culvert where there is insufficient cover material present. Minimum cover criteria should be in accordance with FDOT standard specifications.

Backfill placed adjacent to the walls should consist of granular soils that are free draining and relatively free of fines. The backfill within 5 feet of the walls should be placed in thin lifts and compacted with hand-held compactors to at least 95 percent of the modified Proctor (ASTM D-

1557) maximum dry density value. Over-compaction of the backfill should be avoided since it could cause excessively large earth pressures to develop against the walls. Heavy equipment should be kept at least 5 feet away from the walls.

4.7 UPLIFT RESISTANCE

Permanent structures submerged below the groundwater 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 unit shearing resistance may be determined by the following formula:

Unit Shearing Resistance, F = K0γmh (⅔ tan φ) (above groundwater table)

Unit Shearing Resistance, F = K0 [γmhw + γb(h - hw)] (⅔ tan φ) (below groundwater table)

Where:

F = unit shearing resistance (psf)

K0 = coefficient of earth pressure at rest = 0.5 γm = unit weight of moist soil = 110 pcf γb = buoyant unit weight of soil = 48 pcf h = vertical depth (feet) below grade at which shearing resistance is determined hw = vertical depth (feet) below grade to groundwater table φ = angle of internal friction of the soil = 30 degrees

The values given for the above parameters assume that the permanent structures are covered by clean, well compacted granular backfill that extends horizontally at least 2 feet beyond the structures. An appropriate safety factor should be applied to the unit shearing resistance calculated using the preceding equations.

4.8 LATERAL EARTH PRESSURE ON SHORING AND BRACING

If temporary shoring and bracing is required for any excavations, the system should be designed to resist lateral earth pressure. The design earth pressure will be a function of the flexibility of the shoring and bracing system. For a flexible system restrained laterally by braces placed as the excavation proceeds, the design earth pressure for shoring and bracing can be computed using a uniform earth pressure distribution with depth. It is recommended that soils be de-watered around the excavations. For such de-watered excavations, we recommend using the following uniform pressure distribution over the full braced height as follows:

Uniform Soil Pressure Distribution, p = 0.65KaγsH

Where:

p = uniform pressure distribution for design of braced excavation

Ka = coefficient of active earth pressure = 0.33 γs = unit weight of saturated soils = 125 pcf

H = depth of excavation

An appropriate factor of safety should be applied for the design of the braced excavations.

Lateral pressure distributions determined in accordance with the above do not take hydrostatic pressures or surcharge loads into account. To the extent that such pressures and forces may act on the walls, they should be included in the design.

Construction equipment and excavated fill should be kept a minimum distance of 5 feet from the edge of the braced or shored excavation. Backfill material placed adjacent to (maintaining a minimum 5-foot horizontal clearance) the braced or shored excavation should have a minimum slope of 2.0H:1.0V, or flatter if required by site specific conditions and/or to meet OSHA requirements.

Means and methods of excavation and bracing should be the responsibility of the Contractor;

however, excavation and/or bracing should at a minimum adhere to the requirements of the

Occupational Safety Health Administration (OSHA).

4.9 LATERAL EARTH PRESSURE ON THE BOX CULVERT

Lateral loads acting on the embedded structures will include at-rest earth pressures as well as hydrostatic pressures and surcharge loads. The lateral earth pressure will be a function of both the soil unit weight (submerged or moist) and the depth below ground surface. The following equations can be used to determine the lateral at-rest earth pressure:

σh = K0 γm h (above groundwater table) σh = K0 [γm hw + γb (h - hw)] (below groundwater table)

Where:

σh = lateral earth pressure (psf)

K0 = coefficient of at rest earth pressure (0.5) (this value assumes that the backfill is lightly compacted yet not overcompacted) γm = moist unit weight of compacted soil above the water table = 110 pcf γb = buoyant unit weight of compacted soil below the water table = 48 pcf h = vertical depth (feet) below grade at which lateral earth pressure is determined hw = vertical depth (feet) below grade to groundwater table

For design, an appropriate factor of safety should be applied to the lateral earth pressure calculated using the above equation. Lateral pressure distributions determined in accordance with the above do not include hydrostatic pressures or surcharge loads. Where applicable, hydrostatic pressures and/or surcharge loads should be incorporated in the design.

5 REPORT LIMITATIONS

The evaluations and recommendations submitted herein are based on the data obtained from soil borings performed at the locations indicated. Regardless of the thoroughness of a geotechnical exploration, there is always a possibility that conditions at other locations will be different from those at the specific boring locations and that conditions will not be as anticipated by the designers or contractors. MC2 is not responsible for the conclusions, opinions, and recommendations made by others based on the data presented in this report.

This report has been prepared for the exclusive use of Ayres and Pasco County in accordance with generally accepted geotechnical engineering practices for the specific application to the proposed box culvert extension at Fort King Road, in Pasco County, Florida. No other warranty expressed or implied is made.

APPENDIX

Project Location Map – Sheet 1

USGS Topographic Map - Sheet 2

USDA Soil Survey Map – Sheet 3

Boring Location Map – Sheet 4

Soil Boring Profile – Sheet 5

Summary of Laboratory Test Results – Table 1

Summary of Corrosion Test Results – Table 2

Summary of Soil Parameters – Table 3

Test Procedures

Project Location MapNAMEDATE APPROVED BY:REVISION

SUPERVISED BY:

CHECKED BY:

DRAWN BY:

DESIGNED BY:

SHEET NO.MC PROJ. NO.2 DATENAME

KF

KF

KL

9/5/2024 9/5/2024 9/10/2024 T022403.017

Fort King Sidewalk LAP - Box Culvert Pasco County, Florida

5911 Breckenridge Parkway, Suite G Tampa, FL 33610 Ph:813-623-3399 Fax:813-623-6636

Geotechnical Consultants

MC SQUARED, LLC

KL

FLORIDA ENGINEERING CERTIFICATE OF

AUTHORIZATION No. 9191

Kristina LaCava, P.E.

FLORIDA LICENSE No. 77594

LEGEND:LEGEND:

Project Location

Approximate Project Location

Source: Google Earth Image Date: 1/29/2024

Graphic Scale (feet)

0' 1000'500'

SUPERVISED BY:

CHECKED BY:

DRAWN BY:

DESIGNED BY:

DATENAME

KL

KF

9/5/2024 9/5/2024

9/10/2024

KF

KL

SHEET NO.MC PROJ. NO.2

Fort King Sidewalk LAP - Box Culvert Pasco County, Florida T022403.017 2

USGS Topographic Map

Approximate Project Alignment

SUPERVISED BY:

CHECKED BY:

DRAWN BY:

DESIGNED BY:

DATENAME

KL

KF

9/5/2024 9/5/2024

9/10/2024

KF

KL

SHEET NO.MC PROJ. NO.2

Fort King Sidewalk LAP - Box Culvert Pasco County, Florida T022403.017 3

Source: Natural Resources Conservation Service The survey data is Version 22 dated Sep 6, 2023, with aerial images taken Jan 6, 2022 - Jan 30, 2022.

USDA Soil Survey Map

B-02

B-01

HA-01

Boring Location MapNAMEDATE APPROVED BY:REVISION

SUPERVISED BY:

CHECKED BY:

DRAWN BY:

DESIGNED BY:

SHEET NO.MC PROJ. NO.2 DATENAME

KF

KF

KL

5911 Breckenridge Parkway, Suite G Tampa, FL 33610 Ph:813-623-3399 Fax:813-623-6636

Geotechnical Consultants

MC SQUARED, LLC

KL

FLORIDA ENGINEERING CERTIFICATE OF

AUTHORIZATION No. 9191

Kristina LaCava, P.E.

FLORIDA LICENSE No. 77594

9/5/2024 9/5/2024 9/10/2024 T022403.017

Fort King Sidewalk LAP - Box Culvert Pasco County, Florida

LEGEND:

Approximate Boring Location

Graphic Scale (feet)

0' 100'50'

Source: Google Earth Image Date: 1/29/2024

BORING TERMINATED AT 40'

N

BORING NO.

DATE

LATITUDE

LONGITUDE

B-01 8/16/2024 28.354828° -82.199985°

DE

PT

H (F

EE

T)

DE

PT

H (F

EE

T)

AUGER TERMINATED AT 5'

NMC: 47

OC: 19

LIGHT GRAY FINE SAND (SP)

BORING TERMINATED AT 50'

N

BORING NO.

DATE

LATITUDE

LONGITUDE

B-02 8/16/2024 28.354989° -82.199959°

BORING NO.

DATE

LATITUDE

LONGITUDE

HA-01

8/16/2024 28.354933° -82.199899°

GNA GNA

HA

HA

NMC: 7

-200: 2

NMC: 21

-200: 13

YELLOWISH BROWN TO GRAYISH

BROWN FINE SAND (SP)

GRAY TO YELLOWISH BROWN TO

PALE BROWN CLAYEY SAND (SC)

HA

HA

YELLOWISH BROWN TO

BROWN TO PALE BROWN

FINE SAND (SP)

GRAY TO YELLOWISH BROWN TO PALE

BROWN CLAYEY SAND (SC)

PALE BROWN SANDY CLAY (CH)

PALE BROWN SAND WITH SILT (SP-SM)

NMC: 25

-200: 52

NMC: 17

-200: 22

GNE DARK GRAY ORGANIC SAND WITH SILT (SP-SM)

GRAYISH BROWN SAND WITH SILT (SP-SM)

LEGEND:

CLAY (HIGH PLASTICITY)

SAND

CLAYEY FINE SAND UNIFIED SOIL CLASSIFICATION SYSTEM(SP)NMC=0

OC=0

-200=0

NATURAL MOISTURE CONTENT (%)

ORGANIC CONTENT (%)

FINES PASSING No. 200 SIEVE (%)

STANDARD PENETRATION RESISTANCE IN

BLOWS PER FOOT UNLESS OTHERWISE NOTED N

SAND WITH SILT

GROUNDWATER NOT APPARENTGNA

GROUNDWATER NOT ENCOUNTEREDGNE

ORGANIC SAND WITH SILT

1) LAYER BOUNDARIES ARE APPROXIMATE AND REPRESENT SOIL LAYERS AT THE

TEST LOCATION ONLY. SUBSURFACE VARIATIONS SHOULD BE ANTICIPATED.

NOTES:

2) BASED ON A REVIEW OF THE SOUTHWEST FLORIDA WATER MANAGEMENT

DISTRICT POTENTIOMETRIC MAPS OF THE UPPER FLORIDAN AQUIFER FOR THIS

PROJECT AREA, THE POTENTIAL ARTESIAN HEAD ELEVATION IS ESTIMATED TO

BE +70 FEET NGVD29. THE CONTRACTOR SHALL BE PREPARED TO HANDLE

ARTESIAN WATER LEVELS UP TO ELEVATION +70 FEET NGVD29.

SAFETY HAMMER:

STANDARD PENETRATION TEST DATA

SPOON INSIDE DIA. 1 38 in.

SPOON OUTSIDE DIA. 2 in.

ASTM STANDARD DROP SAFETY HAMMER

AVG. HAMMER DROP 30in.

HAMMER WEIGHT 140 lbs.

GRANULAR MATERIALS

RELATIVE SPT

DENSITY (BLOWS/FOOT)

VERY LOOSE LESS THAN 4

LOOSE 5-10

MEDIUM DENSE 11-30

DENSE 31-50

VERY DENSE GREATER THAN 50

SILTS AND CLAYS

RELATIVE SPT

CONSISTENCY (BLOWS/FOOT)

VERY SOFT LESS THAN 2

SOFT 3-4

FIRM 5-8

STIFF 9-15

VERY STIFF 16-30

HARD GREATER THAN 30

ENVIRONMENTAL CLASSIFICATION

SUPERSTRUCTURE STEEL CONCRETE

SUBSTRUCTURE

SLIGHTLY

AGGRESSIVE

SLIGHTLY

AGGRESSIVE

SLIGHTLY

AGGRESSIVE

REVISIONS

DATE BY DESCRIPTION DATE BY DESCRIPTION

DRAWN BY

CHECKED BY:

DESIGNED BY:

CHECKED BY:

KL

KF

KF

KL

PASCO COUNTY, FLORIDA

ROAD NO. COUNTY

PASCO

PROJECT NAME:

FORT KING SIDEWALK LAP - BOX CULVERT

SHEET TITLE:

SOIL BORING PROFILE SHEET

NO.

T H E O

F F

IC

IA

L R

E C O R D O

F T

H

IS

S H E E T I S T

H E E

L E C T R O N

IC

F

IL

E D

IG

IT

A L L Y S

IG

N E D A

N D S

E A L E D U

N D E R R

U L E

1G

-2 .0

F .A

.C

KRISTINA LACAVA, P.E.

5911 BRECKENRIDGE PARKWAY, SUITE G

P.E. LICENSE NUMBER 77594

MC SQUARED, LLC

TAMPA, FLORIDA 33610

Grain Size

Distribution

#200

B-01 6.0 - 8.0 2 -- 7 SP

B-01 23.5 - 25.0 13 -- 21 SC

B-02 18.5 - 20.0 22 -- 17 SC

B-02 38.5 - 40.0 52 -- 25 CH

HA-01 0.0 - 0.5 -- 18.5 47

-- = Property Not Measured

TABLE 1

SUMMARY OF LABORATORY TESTING

FORT KING SIDEWALK LAP - BOX CULVERT

PASCO COUNTY, FLORIDA

MC

PROJECT NO. T022403.017_G

Organic Content

USCS

Classification Boring Depth (ft)

Natural

Moisture

Content

Steel Concrete

HA-01 1.0 - 5.0 7.87 35 0 25,256 Slightly Aggressive Slightly Aggressive

Water

(2) - - - - - - -

Notes:

(1) Per FDOT Structures Design Guidelines (2024), Section 1.3.2, Table 1.3.2-1

(2) There was no water present in the Creek at the time of our exploration. Therefore, a water sample was not obtained.

TABLE 2

FORT KING SIDEWALK LAP - BOX CULVERT

MC

PROJECT NO. T022403.017_G

PASCO COUNTY, FLORIDA

SUMMARY OF CORROSION TESTING

Boring ID pH

Individual Environmental Classification (1)

Depth

(ft)

Chlorides

(ppm)

Sulfates

(ppm)

Resistivity

(ohm-cm)

0-13 HA, 5-20 SP 105 42.6 30 0.34 2.98 0

13-40 8-27 SC 110 47.6 31 0.32 3.15 0

0-13 HA, 8-24 SP 105 42.6 30 0.33 3.00 0

13-33 5-18 SC 105 42.6 30 0.33 3.02 0

33-43 7-10 CH 115 52.6 - 1.00 1.00 1,125

43-50 10-17 SP-SM 105 42.6 31 0.32 3.10 0

*Reported SPT N values are field values

** Based on emprical correlation

*** Values are for level (non-sloping) backfill; no surchage loads on backfill

TABLE 3

NOTE: Hand augers were performed in the top 4 feet at all test boring locations to avoid utilities. We assumed that the soils within the top 4 feet have a loose relative density with N-Value of 5.

Passive Kp

Earth Pressure Coefficients*** N Value

Range*

Soil

Classification

Depth

(ft) Saturated

(pcf)

Submerged

(pcf)

Average Unit Weight (γ)** Ø**

(degrees) Active Ka

B-02

SUMMARY OF SOIL PARAMETERS

FORT KING SIDEWALK LAP - BOX CULVERT

PASCO COUNTY, FLORIDA

MC

PROJECT NO. T022403.017_G

B-01

Average

Cohesion***

(psf)

TEST PROCEDURES

The general field procedures employed by MC Squared, LLC (MC2) are summarized in the American Society for Testing and Materials (ASTM) Standard D420 which is entitled "Standard Guide for Site Characterization for Engineering Design and Construction Purposes.” This recommended practice lists recognized methods for determining soil and rock distribution and groundwater conditions. These methods include geophysical and in-situ methods as well as borings.

STANDARD DRILLING TECHNIQUES

To obtain subsurface samples, borings are drilled using one of several alternate techniques depending upon the subsurface conditions. Some of these techniques are:

In Soils:

a) Continuous hollow stem augers.

b) Rotary borings using roller cone bits or drag bits, and water or drilling mud to flush the hole.

c) "Hand" augers.

d) Sonic drilling.

In Rock:

a) Core drilling with diamond-faced, double or triple tube core barrels.

b) Core boring with roller cone bits.

The drilling methods used during this exploration are presented in the following paragraphs.

Rotary Borings: The rotary drilling method is advantageous where the stability of the borehole wall in drilling unconsolidated formations is not possible. In this case the introduction of a bentonite slurry is used to provide a buildup of filter cake on the wall, preventing collapse. The disadvantage of using this method is the filter cake may alter the hydraulic characteristic of the borehole resulting in accurate groundwater readings to be difficult. This method uses a core barrel and rotary bit to advance through the soil along with a mud pit as a reservoir for the drilling fluid.

Hand Auger Borings: Hand auger borings are conducted using a 3-inch diameter manual bucket auger to advance the boring in 4 to 6-inch in general accordance with ASTM D1452. Hand auger borings are limited in depth due to borehole collapse, which is common when manually advancing borings below the water table or auger refusal on an obstruction.

SAMPLING AND TESTING OF SOILS IN BOREHOLES

Several techniques are used to obtain samples and data in soils in the field; however, the most common methods in this area are:

a) Standard Penetration Testing and Split Barrel Sampling of Soils

b) Thin-walled Tube (Shelby Tube) Sampling

c) Static Cone Penetrometer Testing

d) Dynamic Cone Penetrometer (DCP) Testing

e) Water Level Readings

The procedures utilized for this project are presented below.

Standard Penetration Testing: At regular intervals, the drilling tools are removed, as required, and soil samples obtained with a standard 2-inch diameter split tube sampler connected to an A or N-size rod. The sampler is first seated 6 inches to penetrate any loose cuttings, then driven an additional 12 inches with blows of a 140-pound safety hammer falling 30 inches. Generally, the number of hammer blows required to drive the sampler the final 12 inches is designated the "penetration resistance" or "N" value, in blows per foot (bpf). The split barrel sampler is designed to retain the soil penetrated, so that it may be returned to the surface for observation. Representative portions of the soil samples obtained from each split barrel sample are placed in jars, or air-tight containers, labeled and transported to our laboratory.

The standard penetration test, when properly evaluated, provides an indication of the soil strength and compressibility. The tests are conducted according to ASTM Standard D1586. The depths and field “N”-values of standard penetration tests are shown on the boring logs. Samples obtained from split barrel samplers are suitable for visual observation and classification tests but are not sufficiently intact for quantitative laboratory testing.

Many times, an automatic hammer is used during drilling procedures. In this case, the field “N”-value is recorded on the Boring Log and a correction is made to the “N”-value based on the energy transfer ratio for the drill rig utilized on the project. The “N60” value is used in determining the strength and compressibility of the soil.

Water Level Readings: Water level readings are normally taken in the borings and are recorded on the boring logs. In sandy soils, these readings indicate the approximate location of the hydrostatic water level at the time of our field exploration. In clayey soils, the rate of water seepage into the borings is low and it is generally not possible to establish the location of the hydrostatic water level through short-term water level readings. Also, fluctuation in the water level should be expected with variations in precipitation, surface run-off, evaporation, and other factors. For long-term monitoring of water levels, it is necessary to install piezometers.

The water levels reported on the boring logs are determined by field crews immediately after the drilling tools are removed, and several hours after the borings are completed, if possible. The time lag is intended to permit stabilization of the groundwater level that may have been disrupted by the drilling operation.

Occasionally, the borings will cave-in or require immediate backfilling upon completion, preventing water level readings from being obtained or trapping drilling water above the cave-in zone.

BORING LOGS

The subsurface conditions encountered during drilling are reported on a field boring log prepared by the engineer or geologist. The log contains information concerning the drilling method, samples attempted and recovered, indications of the presence of coarse gravel, cobbles, deleterious material which may affect the project, rock quality including recovery and rock quality designation (RQD) percentages, observations of groundwater, and other pertinent core drilling information. It also contains the field engineer’s or geologist’s interpretation of the soil conditions between samples. Therefore, these boring records contain both factual and interpretive information. The field boring records are kept on file in our office. After the drilling is completed, a geotechnical professional reclassifies the soil and rock samples, if required, in a laboratory environment and prepares the final boring logs, which are the basis for our evaluations and recommendations.

SOIL CLASSIFICATION

Soil classifications provide a general guide to the engineering properties of various soil types and enable the engineer to apply his past experience to current problems. In our investigations, samples obtained during drilling operations are re-examined in our laboratory to confirm visual classification by a geotechnical engineer or geologist. The soils are classified according to relative density or consistency (based on number of blows from standard penetration tests), color and texture. These classification descriptions are included on our boring logs.

The classification system discussed above is primarily qualitative, and for detailed soil classification, two (2) geotechnical laboratory tests are necessary: grain size tests and plasticity tests. Using these test results, the soil was classified according to the Unified Classification Systems (ASTM D2487). Each of these classification systems and the in-place physical soil properties provides an index for estimating the soil's behavior. The soil classification and physical properties are presented in this report.

The following table presents criteria that are typically utilized in the classification and description of soil and rock samples for preparation of the boring logs.

Relative Density of Cohesionless Soils

From Standard Penetration Test Consistency of Cohesive Soils

Very Loose < 4 bpf

Loose 5 - 10 bpf

Medium Dense 11 - 30 bpf

Dense 31 - 50 bpf

Very Dense > 50 bpf

(bpf = blows per foot, ASTM D1586)

Very Soft < 2 bpf

Soft 3 - 4 bpf

Firm 5 - 8 bpf

Stiff 9 - 15 bpf

Very Stiff 16 - 30 bpf

Hard > 30 bpf

Relative Hardness of Rock Particle Size Identification

Very Soft disintegrates or easily compresses to touch; can be hard to very hard soil.

Soft May be broken with fingers.

Moderately Soft May be scratched with a nail, corners and edges may be broken with fingers.

Moderately Hard Light blow of hammer required to break samples.

Hard Hard blow of hammer required to break sample.

Boulders Larger than 12"

Cobbles 3" - 12"

Gravel

Coarse 3/4" - 3"

Fine 4.76 mm - 3/4"

Sand

Coarse 2.0 - 4.76 mm

Medium 0.42 - 2.00 mm

Fine 0.42 - 0.074 mm

Fines

(Silt or Clay) Smaller than 0.074 mm