Appendix_E_-_Geotechnical_Report.pdf

Appendix E Geotechnical Report

Report Geotechnical Engineering Services

Relocation of Lift Station C-17 SE Corner of N. Courtenay Parkway and Catalina Isle Drive Merritt Island, Florida

PSI Project No. 07573106

Project Number: 07573106 February 14, 2024

Updated February 16, 2024

Engineering Certificate of Authorization 3684 www.intertek.com/building

Professional Service Industries, Inc.

1748 33rd Street, Orlando, FL 32839

Phone: (407) 304-5560 Fax: (407) 304-5561

Mr. Tucker Hunter, P.E.

Kimley-Horn & Associates, Inc.

7341 Office Park Place Suite 102 Melbourne, FL 32940

RE: Report Geotechnical Engineering Services

Relocation of Lift Station C-17 SE Corner of N. Courtenay Parkway and Catalina Isle Drive Merritt Island, Florida

Dear Mr. Hunter:

In general accordance with PSI Proposal No. 0757-400851, Professional Service Industries, Inc. (PSI), an Intertek Company, has completed a subsurface exploration program at the site of the referenced project.

The subsurface exploration was conducted to provide geotechnical engineering recommendations to guide design and construction of the proposed relocation of Lift Station C-17. The following report presents the results of our work effort on the project plus it provides our recommendations pertaining to the geotechnical aspects of the project. This updated report incorporates corrected site-specific topographic data recently provided to PSI.

PROJECT INFORMATION

The project under consideration herein is the replacement and relocation of existing lift station C-17 that is presently located on a property at the southeast corner of North Courtenay Parkway and Catalina Isle Drive in Merritt Island, Florida. The current lift station is located in the southeast corner of a former carwash business that has been closed for a few years. The existing groundcover at the site comprises concrete and asphalt pavement associated with the former car wash and Catalina Isle Drive.

From the information provided, we understand the lift station will be replaced (new construction) and relocated into a 40 foot by 40 foot easement north of its current location and in the northeast of the subject property. The project will also include a new rerouted gravity main sewer line below Catalina Isle Drive that will tie into the relocated lift station. The rerouted gravity sewer will most likely be installed via jack and bore. We further understand that the new lift station and rerouted gravity main will be on the order of 30 feet deep and 20 feet deep, respectively.

If any of the stated information is incorrect or has changed, PSI should be notified so appropriate changes to our recommendations can be incorporated into this report.

February 16, 2024

REVIEW OF PUBLISHED INFORMATION

USGS Topographic Map

The topographic survey map published by the USGS entitled “Cocoa, Florida” was reviewed for ground surface features in the area of the project. Based on this review, the natural ground surface elevation is reported to be on the order of +10 feet National Geodetic Vertical Datum of 1929 (NGVD 1929). A review of topographic data contained in the provided site plan indicates the existing ground surface in the vicinity of the proposed upgrades to be in the general range +8 to +10 feet North American Datum of 1983 (NAD83), 2012 adjustment.

SCS Soil Survey

The “Soil Survey of Brevard County, Florida”, as contained on the NRCS Web Soil Survey was reviewed for general near-surface soil information within the general project vicinity. This information indicates that the project site is underlain by one soil mapping unit. The general information provided by the NRCS for the mapped soil unit is summarized in the following table.

Soil Series Depth (inches)

Unified Classification

USDA Seasonal High Groundwater Table

Depth (feet)

36 – Myakka sand, 0 to 2 percent slopes 0 to 80 SP-SM 0.5 to 1.5

It should be noted that the listed information from the Soil Survey is based on pre-development conditions.

FIELD EXPLORATION

General

To evaluate subsurface conditions at the site, PSI drilled/sampled one Standard Penetration Test (SPT) boring to a depth of 50 feet below the existing ground surface at the planned replacement lift station location, plus one SPT boring to a depth of 30 feet below grade for the planned gravity main sewer line. The SPT borings were drilled/sampled following Standard Penetration Test (SPT) procedures in general accordance with ASTM D-1586. The upper 4 feet of the SPT borings was augered by hand to confirm clearance from shallow buried utilities. Below this depth, SPT samples were collected at 5, 7 and 9 feet with the sampling frequency being at 5-foot centers thereafter to boring termination. The approximate locations at which the SPT borings were drilled are shown on Sheet 1. The boring for the planned gravity main was offset to an accessible grass area on the south side of Catalina Isle Drive and within the former car wash property. Prior to drilling the borings, PSI engaged the services of a specialty subcontractor to perform private utility locates for avoidance at the boring locations.

The soil samples recovered from the borings were returned to our Orlando laboratory for visual stratification and select testing. Subsoils were visually stratified following the guidelines contained in the Unified Soil Classification System (USCS). Laboratory testing comprised several natural moisture content determinations and No. 200 wash sieve analyses (percent fines passing the U.S. Standard No. 200 sieve). Records of the materials encountered in the borings are presented as soil profiles on Sheet 2. Sheet 2 includes a legend describing the subsoils in USCS format as well as presenting the results of the laboratory tests.

The stratification presented is based on visual observation of the recovered soil samples, laboratory testing and interpretation of the field log by a geotechnical engineer. It should be noted that variations in the subsurface conditions are expected and may be encountered between and away from the boring. Also, whereas the individual boring logs indicate distinct strata breaks, the actual transition between the soil layers may be more gradual than shown on the soil profiles.

Soil Conditions

Based on the results of the borings completed for the project, subsoils beneath the existing ground cover (grass or concrete pavement) generally comprise a varying sequence of fine sands from the ground surface to depths of 30 to 50 feet below grade (terminal limits of the borings). The sands grade relatively clean to slightly silty and occasionally silty in composition (i.e. SP, SP-SM and SM materials). Intermixed with some of the sands at varying depths were trace amounts of small shell and shell fragments. The upper sands in boring B-2 (drilled in a grassed swale-type area adjacent to the roadway) contained trace small roots and organic debris likely associated with the surface vegetation and frequent saturated conditions from stormwater runoff.

Recorded SPT blow counts indicate the sands for the most part to be in a loose to medium dense condition, with an isolated zone of very loose sands around 25 feet below existing grade.

A more detailed description of the soils observed in the borings is shown on the soil profiles on Sheet 2.

Groundwater Conditions

Groundwater was encountered in the borings at depths of 2.2 to 2.4 feet below grade at the time of drilling (January 2024). Water levels will fluctuate seasonally in response to rainfall or lack thereof. Additionally, water levels will to some degree be influenced by irrigation practices and drainage improvements in the area.

The estimated normal seasonal high groundwater levels presented herein are based on the observed soil stratigraphy, measured groundwater levels in the borings, USDA Soil Survey information, and our past experience in the project vicinity. In this regard, we estimate the normal seasonal high groundwater table will occur within 0.5 to 1.5 feet of the natural predevelopment ground surface consistent with the Web Soil Survey.

In general, the normal seasonal high groundwater level is not intended to define a limit or ensure that future seasonal fluctuations in groundwater levels will not exceed the estimated levels. Post-development groundwater levels could exceed the normal seasonal high groundwater level estimate as a result of a series of rainfall events, changed conditions at the site that alter surface water drainage characteristics, or variations in the duration, intensity, or total volume of rainfall.

SITE PREPARATION CONSIDERATIONS

Based on the results of the borings and laboratory testing, subsoil conditions are generally considered suitable for construction of the proposed replacement lift station and gravity sewer line from a geotechnical engineering perspective. The following recommendations have been developed on the basis of the previously described project characteristics and subsurface conditions encountered. If there is any change in the project criteria, a review must be made by PSI to determine if additional fieldwork and/or any modifications to our recommendations will be required.

Once final design plans and specifications are available, a general review by PSI is strongly recommended as a means to check that the evaluations made in preparation of this report are correct and that the noted recommendations are properly interpreted and implemented.

Site Clearing/Stripping

At the outset of construction, clearing and grubbing including root raking and removal of any organic-laden topsoil that may remain on site should be completed. This normally includes removing the surface vegetation and trees, grubbing major root systems, stripping topsoil, and removing any miscellaneous debris, organic soils and/or deleterious materials. Site clearing should also include the demolition/removal of existing conflicting construction as appropriate, including the complete removal of foundations, pavements and buried utilities/pipes associated with the same (if any). The excavations resulting from the removal of the below ground construction should be backfilled with clean sand that is placed and compacted in lifts. Material generated during stripping/clearing operations should be disposed of off-site in a proper manner as directed by the Owner.

The limits of clearing should extend at least 10 feet beyond the outside edges of the proposed construction whenever practical. The exposed subgrade following these operations should comprise suitable sand soils consisting of either engineered fill material or the native sands. Care should be exercised during initial site clearing and site preparation activities so as not to disturb existing construction that is to remain.

Initial site clearing and preparation work should be carried out under the observation of a representative of the geotechnical engineer.

Fill Placement and Subgrade Preparation

Following the clearing/stripping operations, the exposed subgrade should be evaluated as directed by the Geotechnical Engineer or his representative to confirm that all unsuitable materials have been removed. New development areas should then be proof-rolled to provide a stable/unyielding subgrade prior to placing fill.

Proof rolling should consist of compaction with a large diameter, vibratory drum roller. The roller should have a drum weight of at least ten tons. Proof rolling should consist of a minimum of ten overlapping coverages of the roller in a criss-cross pattern with a maximum travel speed of 2 feet per second.

Compaction can be completed in the vibratory or static mode in order to meet the minimum density requirements stated below. Based on past experience, we recommend compaction equipment be operated in the static mode within 75 feet of existing structures to reduce vibrations that could cause structural distress or disturb building occupants. Careful observations should be made during proof rolling to help identify any areas of soft/yielding soils that may indicate the presence of unsuitable soils that require over-excavation and replacement filling.

It is recommended that the subgrade, to a minimum depth of one foot below stripped grade, be compacted to at least 95 percent of the soil’s modified Proctor (ASTM D-1557) maximum dry density within new development areas (pavements, hardscape and the like). Following satisfactory completion of initial compaction of the stripped subgrade, the proposed development area may be brought up to finished grades as required. Pipe bedding soils should similarly be compacted to at least 95 percent of the material’s modified Proctor (ASTM D-1557) maximum dry density to a minimum depth of 12 inches below the bottom of the pipe.

Pipe backfill should be placed in lifts no thicker than 12 inches. Due to the confined work area, it may be necessary to use a light, jumping jack or vibratory plate compactor. If light compaction equipment is used, backfill lifts may need to be limited to 6 inches to achieve the required compaction. Compact the pipe backfill material to at least 95 percent of the material’s modified Proctor (ASTM D-1557) maximum dry density.

Density tests should be performed to confirm the required compaction is being achieved prior to placing the next lift. Where utility lines will traverse roadways or other permanent structures such as sidewalks and driveways, the backfill should be compacted to at least 98 percent of the material’s modified Proctor (ASTM D-1557) maximum dry density for a depth of 2 feet below the bottom of the pavement section.

Engineered Fill

Any off-site fill imported for the project should consist of clean fine sand with less than 10 percent by dry weight passing the U.S. Standard No. 200 sieve and be free of rubble, organics, clay, debris and other deleterious material. Fill should be tested and approved prior to import and placement. Each lift should have a loose thickness not exceeding 12 inches. Density tests should be performed to confirm the required compaction is being achieved prior to placing the next lift.

Prior to beginning compaction, soil moisture conditioning may be required. Soil moisture contents should be controlled in order to facilitate proper compaction. A moisture content within two percentage points of the material’s optimum indicated by the modified Proctor test (ASTM D-1557) is recommended prior to compaction of the natural ground and fill. All engineered fill should be compacted to at least 95 percent of the material’s modified Proctor (ASTM D-1557) maximum dry density.

Wet Well Construction Considerations

It is anticipated that the excavation for the replacement lift station/wet well will extend to depths up to 30 feet below existing grade. Based on PSI’s understanding of the proposed construction and encountered subsoil conditions, traditional open excavation construction with associated dewatering activities may not be feasible for installation of the new wet well given the built-up nature of the site and the relatively shallow groundwater conditions as disclosed in PSI’s boring. All excavations required for the installation of the wet well and associated below grade elements should be performed in accordance with the appropriate Occupational Safety and Health Administration (OSHA) standards.

As an alternative to conventional open excavation installation methods, the Caisson method or temporary sheeting may be considered to construct the wet well. In general, the Caisson method of construction involves using precast sections of the wet well to support the excavation. The precast sections are placed in a starter excavation and sunk by gravity as the soils are excavated from inside the precast sections.

Consecutive sections are added on top of the previously installed section until the desired depth is obtained.

The subgrade of the wet well base slab should be in a firm and unyielding condition prior to construction. If this method of installation is selected, the contractor should provide a list of successful projects constructed within the last 5 years utilizing the Caisson method for review by the Owner. Temporary sheeting/shoring, if used in construction, should be designed by a licensed professional engineer.

Based on the anticipated construction and soil conditions, the wet well foundation/base slab may be designed for a net allowable bearing pressure of 2,500 pounds per square foot (psf). All below grade elements should be constructed to withstand uplift forces resultant from hydrostatic/buoyancy conditions. It may be necessary to provide uplift resistance beyond that of the weight of the backfill and deadweight of the structure to prevent buoyancy problems. All foundation excavations should be observed by the Geotechnical Engineer or his representative to explore the extent of any fill, excessively loose, soft, or otherwise undesirable materials.

Due to the anticipated modest increase in stresses within the wet well support soils, total settlement of the wet well should be on the order of one inch or less. The settlement of the wet well supported on sandy soils should occur relatively quickly after initial loading. Thus, the majority of the expected settlement should occur during construction as deadloads are imposed.

Earth Pressures on Walls

The wet well for the project should be designed to resist pressures exerted by the adjacent soils and hydrostatic head. For walls that are not restrained during backfilling but are free to rotate at the top, active earth pressure should be used in design. Walls that are restrained should be designed assuming at-rest pressures. Recommended soil parameters for the near-surface granular soils encountered at the site are presented in the following.

Total Unit Weight, T = 120 lb/ft3

Angle of Internal Friction, = 30 Coeff. of Sliding Friction = 0.40 Active Soil Pressure coeff., Ka = 0.33 At-rest Soil Pressure coeff., Ko = 0.50 Passive Soil Pressure coeff., Kp = 3.00

OTHER CONSIDERATIONS

Pavement Support

We understand the new lift station will include a concrete paved driveway/parking area (for the occasional service/maintenance vehicle). We recommend a minimum separation of 18 inches is maintained between the bottom of the pavement base/granular pavement subgrade and the estimated normal seasonal high groundwater table. Based on experience, we recommend the following minimum concrete pavement section for heavy-duty uses such as driveway areas and areas to receive heavy truck traffic.

Heavy-Duty (Rigid Pavement)

7.0 inches Portland cement concrete, minimum 28-day compressive strength of 4000 psi.

12.0 inches Well-draining granular subgrade compacted to 98 percent of the material’s ASTM D-1557 maximum dry density.

Pavement joints and reinforcing for concrete pavement should be in accordance with American Concrete Institute (ACI) standards. The recommended pavement sections are based on past experience with similar projects and the encountered subsurface conditions at the site. All pavement materials and construction should meet the more stringent of the Florida Department of Transportation (FDOT) and local city/county requirements. The noted pavement section should be considered a recommended minimum based on anticipated traffic loadings and our past experience. The project civil engineer should provide the pavement design using actual traffic loads, design criteria provided by the Owner, and the soil/groundwater conditions noted herein.

Site Dewatering

Excavations that are only a few feet below the water table can typically be dewatered with a sump pump.

Deeper excavations will most likely require well pointing or sock drains to achieve adequate drawdown. The dewatering process may have an effect on nearby infrastructure, as lowering the groundwater table will cause an increase of effective stress in the soils. A qualified dewatering contractor should be used to develop a dewatering plan that will avoid impacts on nearby infrastructure. The discharge from the dewatering system should be handled in accordance with current regulatory criteria.

Excavations

In Federal Register, Volume 54, No. 209 (October 1989) the United States Department of Labor, Occupational Safety and Health Administration (OSHA) amended its “Construction Standards for Excavations, 29 CFR, part 1926, Subpart P”. This document was issued to better ensure the safety of workmen entering trenches or excavations. It is mandated by this federal regulation that excavations, whether they be utility trenches, general construction excavations or footing excavations, be constructed in accordance with the new OSHA guidelines. It is our understanding that these regulations are being strictly enforced and if they are not closely followed the Owner and the contractor could be liable for substantial penalties.

The contractor is solely responsible for designing and constructing stable, temporary excavations and should shore, slope, or bench the sides of the excavations as required to maintain stability of both the excavation sides and bottom. The contractor’s “responsible person”, as defined in 29 CFR Part 1926, should evaluate the soil exposed in the excavations as part of the contractor’s safety procedures. In no case should slope height, slope inclination, or excavation depth, including utility trench excavation depth, exceed those specified in local, state, and federal safety regulations.

PSI is providing this information solely as a service to our client. PSI does not assume responsibility for construction site safety or the contractor’s or other parties’ compliance with local, state, and federal safety or other regulations.

REPORT LIMITATIONS

Our professional services have been performed, our findings obtained, and our recommendations prepared in accordance with generally accepted geotechnical engineering principles and practices. This company is not responsible for the conclusions, opinions or recommendations made by others based on these data.

The scope of PSI’s geotechnical exploration was intended to evaluate soil conditions within the influence of the proposed lift station and pipe run and does not include an evaluation of potential deep soil problems such as sinkholes. The analysis and recommendations submitted in this report are based upon the data obtained from the soil borings performed at the locations indicated. If any subsoil variations become evident during the course of this project, a re-evaluation of the recommendations contained in this report will be necessary after we have had an opportunity to observe the characteristics of the conditions encountered. The applicability of the report should also be reviewed in the event significant changes occur in the design, nature or location of the proposed construction.

The scope of our services does not include any environmental assessment or investigation for the presence or absence of hazardous or toxic materials in the soil, groundwater, or surface water within or beyond the site studied. Any statements in this report regarding odors, staining of soils, or other unusual conditions observed are strictly for the information of our client.

CLOSURE

PSI appreciates the opportunity to provide our services to Kimley-Horn on this project and we trust the information presented herein is sufficient for your needs at this time. If you have any questions regarding the contents of this report, or if we may be of further service, please contact the undersigned.

Respectfully submitted, PROFESSIONAL SERVICE INDUSTRIES, INC.

Certificate of Authorization No. 3684

Max S. McGahan, P.E. Ian Kinnear, P.E.

Senior Project Engineer Chief Geotechnical Engineer Florida License No. 86580 Florida License No. 32614

07573106U1 (Replacement of Lift Station C-17, Merritt Island).doc

Attachments

• Sheet 1 – Boring Location Plan

• Sheet 2 – Boring Profiles

APPENDIX

B-1

B-2

N

APPROXIMATE LOCATION OF STANDARD PENETRATION TEST BORING

LEGEND

PROJECT NO.

1748 33rd Street

Orlando, FL 32839

(407)304-5560

(407)304-5561 fax

SCALE:

DATE CREATED:

07573106

1"=60'

1-18-24

SHEET:

DRAWN:

CHECKED:

DJW

MM

SE CORNER OF N. COURTENAY PARKWAY AND CATALINA ISLE DRIVE

RELOCATION OF LIFT STATION C-17

MELBOURNE, FLORIDA

GEOTECHNICAL ENGINEERING SERVICES

AutoCAD SHX Text REFERENCE: THE AERIAL PHOTOGRAPH WAS OBTAINED FROM GOOGLE EARTH. THE PRESENTED DATA IS FOR INFORMATION PURPOSES ONLY. IT IS NOT MEANT FOR DESIGN, LEGAL, OR ANY OTHER USES. INTERTEK-PSI ASSUMES NO RESPONSIBILITY FOR ANY DECISIONS MADE OR ANY ACTIONS TAKEN BY THE USER BASED UPON INFORMATION OBTAINED FROM THE ABOVE DATA.

PROJECT NO.

1748 33rd Street

Orlando, FL 32839

(407)304-5560

(407)304-5561 fax

SCALE:

DATE CREATED:

07573106

NOTED

1-18-24

SHEET:

DRAWN:

CHECKED:

DJW

MM

SE CORNER OF N. COURTENAY PARKWAY AND CATALINA ISLE DRIVE

RELOCATION OF LIFT STATION C-17

MELBOURNE, FLORIDA

GEOTECHNICAL ENGINEERING SERVICES

SOIL PROFILES

SCALE: 1"=10'

GRAY-BROWN FINE SAND TO SLIGHTLY SILTY

FINE SAND, (SP), (SP-SM)

BROWN FINE SAND TO SLIGHTLY SILTY FINE

SAND, (SP), (SP-SM)

GRAY TO GREEN-GRAY SLIGHTLY SILTY FINE

SAND TO SILTY FINE SAND, TRACE SMALL

SHELL, (SP-SM), (SM)

GREEN-BROWN SLIGHTLY SILTY FINE SAND TO

SILTY FINE SAND (SP-SM), (SM)

DARK GRAY FINE SAND TO SLIGHTLY SILTY FINE

SAND, TRACE ROOTS (TOPSOIL), (SP), (SP-SM)

DARK BROWN SILTY FINE SAND, TRACE ROOTS,

(SM)

UNIFIED SOIL CLASSIFICATION GROUP SYMBOL

STANDARD PENETRATION RESISTANCE IN

BLOWS PER FOOT USING AN AUTOMATIC

HAMMER

DEPTH TO GROUNDWATER LEVEL IN FEET WITH

DATE OF READING

NATURAL MOISTURE CONTENT IN PERCENT

FINES PASSING #200 SIEVE IN PERCENT

(SP)

N

W

-200

LEGEND

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6" CONCRETE

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PAVEMENT