Geotechnical_Engineering_Services_Report_.pdf

PDF 3 MB Posted Sep 4, 2025

Attached to: 7th St N, 50th Ave N and Vicinity Storm Drainage Improvements Part 1 (Project No. 19045-110)
Solicitation number: IFB- 25 - 289
Issued by: Pinellas County, Florida

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Written by GovTribe AI · Sep 23, 2025

This document is a Preliminary Geotechnical Engineering Services Report prepared by Tierra, Inc. for Land & Water Engineering Science, Inc. regarding storm drainage improvements for the City of St. Petersburg in Pinellas County, Florida. The project involves preparing construction plans to address flooding issues along 7th Street North from 50th Avenue to the 54th Avenue Canal and on 50th Avenue North from 7th Street to 4th Street. Specific improvements include adding 66-inch or larger conduits, a box culvert, sediment removal sumps, and replacing an existing 48-inch conduit with a larger pipe.

Tierra conducted a comprehensive geotechnical investigation that included six Standard Penetration Test (SPT) borings to depths of 20-35 feet, two hand auger borings, six pavement cores, and sediment probing in the 54th Avenue Canal. The study examined soil conditions, groundwater levels, and pavement characteristics, with groundwater tables measured at 4¼ to 7 feet below existing grades. The soil strata consisted primarily of sand and silty sand with occasional shell fragments. The report provides detailed recommendations for site preparation, excavation, backfill, and structure foundations, emphasizing the need for proper soil compaction, utility clearance, and protection of existing residential structures during construction.

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TIERRA

7351 Temple Terrace Highway • Tampa, FL 33637 Phone (813) 989-1354 • Fax (813) 989-1355

December 14, 2020

Land & Water Engineering Science, Inc.

8950 N. Martin Luther King Street Suite 205 St. Petersburg, Florida 33702

Attn: Mr. Dikran Kalaydjian, P.E. – Principal

RE: Preliminary Geotechnical Engineering Services Report

City of St. Petersburg 7th Street North, 50th Avenue North and Vicinity Storm Drainage Improvements Pinellas County, Florida Tierra Project No. 6511-20-160

Mr. Kalaydjian:

Tierra, Inc. (Tierra) has completed the geotechnical engineering study for the above referenced project. The results of the study are provided herein.

Should there be any questions regarding the preliminary report, please do not hesitate to contact our office at (813) 989-1354. Tierra would be pleased to continue providing geotechnical services throughout the implementation of the project. We look forward to working with you and your organization on this and future projects.

Respectfully Submitted, TIERRA, INC.

William P. Rovira IV, P.E. Erick M. Frederick, P.E.

Geotechnical Engineer Senior Geotechnical Engineer Florida License No. 74586 Florida License No. 63920

TABLE OF CONTENTS

PROJECT DESCRIPTION

Project Information

Scope of Services/Objectives

SITE AND SUBSURFACE CONDITIONS

General Site Information

USGS Quadrangle Maps

Pinellas County Soil Survey

Subsurface Conditions

Groundwater Information

EVALUATION AND RECOMMENDATIONS

General

Potentiometric Surface

Protection of Existing Structures

On-Site Soil Suitability

Site Preparation

Drainage Structures Recommendations

Drainage and Groundwater Concerns

Backfill

Excavations

REPORT LIMITATIONS

APPENDIX

USDA Soil Survey & USGS Quadrangle Map Summary of USDA Soil Survey Boring Location Plan Soil Profile Sheets Sediment Probing Plan Recommended Soil Parameters Pavement Data Table Representative Photographs of Pavement Cores

Preliminary Geotechnical Engineering Services Report City of St. Petersburg 7th Street North, 50th Avenue North and Vicinity Storm Drainage Improvements Pinellas County, Florida Tierra Project No. 6511-20-160

PROJECT DESCRIPTION

Project Information

The proposed project consists of preparing construction plans for storm drainage improvements to address flooding issues on 7th Street North from 50th Avenue to the 54th Avenue Canal and on 50th Avenue North from 7th Street to 4th Street. The storm water improvements include the addition of 66-inch or larger conduits along 7th Street North and 50th Avenue, a box culvert and sediment removal sumps at the 54th Avenue Canal. An existing 48-inch conduit is also anticipated to be replaced by a larger pipe along 7th Street North.

Scope of Services/Objectives

The objective of our study was to evaluate existing soils with respect to the proposed force main and water main pipelines. In order to meet this preceding objective, we provided the following services:

1. Reviewed the “Saint Petersburg, Florida” Quadrangle Map published by the United States Geological Survey (USGS), as well as the Soil Survey of Pinellas County, Florida, published by the United States Department of Agriculture (USDA) Natural Resources Conservation Service (NRCS).

2. Conducted a visual reconnaissance of the project site and coordinated utility clearance.

3. Coordinated and obtained the appropriate Right-of-Way use permit for performing SPT borings/pavement cores within the travel lanes along the proposed pipe alignments.

4. Performed Maintenance of Traffic (MOT) services for borings/pavement cores performed within the travel lanes in accordance with the appropriate FDOT Standard Plans Indices.

5. Coordinated with the owner of the property located at 697 53rd Terrace North to obtain access to the proposed outfall culvert structure at 54th Avenue Canal.

6. Performed site clearing/trimming of vegetation in the vicinity of the proposed outfall culvert structure to allow access to our drilling equipment.

7. Performed a total of six (6) Standard Penetration Test (SPT) borings as follows:

• Three (3) SPT borings to a depth of 20 to 25 feet along the project corridor (2 borings along 7th Street and 1 along 50th Avenue).

7th Street North, 50th Avenue North and Vicinity Storm Drainage Improvements Pinellas County, Florida

• Two (2) SPT borings on the banks of 54th Avenue Canal (near each end of the culvert crossing under 4th Street) to a depth of 20 feet for proposed sediment removal sumps.

• One (1) SPT boring to a depth of 35 feet at the proposed outfall canal structure.

8. Performed two (2) hand auger borings to depths of 4½ and 5½ feet along the project corridor.

9. Measured the groundwater level at the boring locations. Estimated the Seasonal High Groundwater Table (SHGWT) levels at select boring locations.

10. Performed six (6) pavement cores within paved areas to identify the pavement type/thickness and base type/thickness at each location.

11. Patched each pavement core/boring location performed through the pavement upon completion.

12. Performed sediment probing within the 54th Avenue Canal in the areas of the proposed sediment removal sumps to determine the thicknesses of sediment present in the canal.

13. Visually classified the samples in the laboratory using the Unified Soil Classification System (USCS). Identified soil conditions at each boring location and conducted laboratory classification testing to confirm visual review.

14. Prepared a preliminary engineering report, in accordance with the scope of services herein, which summarizes the course of study pursued, the field data generated, subsurface conditions encountered and our engineering recommendations in each of the pertinent topic areas. The analyses include an evaluation of temporary side slopes and alternate excavation methods including trench boxes and sheet pile walls.

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 this site. The scope of our services did not include determination of the potential for sinkhole activity. Any statements in this preliminary report or on the boring logs regarding odors, colors, unusual or suspicious items or conditions are strictly for the information of our client.

7th Street North, 50th Avenue North and Vicinity Storm Drainage Improvements Pinellas County, Florida

SITE AND SUBSURFACE CONDITIONS

General Site Information

Land use in the project area consists primarily of residential and commercial developments.

USGS Quadrangle Maps

Based on the “Saint Petersburg, Florida” USGS Quadrangle Map, the natural ground elevation along the project alignment is on the order of +5 to +10 feet, National Geodetic Vertical Datum of 1929 (NGVD).

Pinellas County Soil Survey

Based on a review of the Pinellas County Soil Survey published by the USDA NRCS, it appears that there are three (3) primary soil-mapping units noted within the vicinity of the project limits. The general soil descriptions are presented in the Appendix, as described in the Soil Survey.

It should be noted that information contained in the USDA NRCS Soil Survey may not be reflective of current subsurface conditions, particularly if recent development in the project vicinity has modified existing soils or surface/subsurface drainage.

Subsurface Conditions

Prior to commencing our subsurface explorations, a boring location plan was developed based on project information provided by the design team. The subsurface conditions within the vicinity of the proposed pipe alignments and structures were explored using six

(6) Standard Penetration Test (SPT) borings drilled to depths ranging from 20 to 35 feet below the ground surface.

The borings were located in the field using a Garmin eTrex® hand-held Global Positioning System (GPS) unit with a reported accuracy of ±10 feet. The approximate boring locations are presented on the Boring Location Plan sheet in the Appendix.

The SPT borings were performed with the use of a drill rig using Bentonite Mud drilling procedures. The soil sampling was performed in general accordance with American Society for Testing and Materials (ASTM) Test Designation D-1586. Within the SPT borings, the initial 4 to 6 feet were advanced by manually auger to verify utility clearance.

SPT resistance N-values were then recorded continuously to a depth of 10 feet and on intervals of 5 feet thereafter to the boring termination depth. The soil samples were classified in the field and transported to our laboratory for review.

7th Street North, 50th Avenue North and Vicinity Storm Drainage Improvements Pinellas County, Florida

Tierra performed six (6) pavements cores within the 50th Avenue N and 7th Street N roadway travel lanes to identify the pavement type/thickness along with a hand auger boring to identify the base type/thickness present. The pavement cores were performed with the use of a 4-inch outside diameter core bit. The asphalt pavement was visually classified using standard FDOT nomenclature. The hand auger borings were performed by manually twisting and advancing a bucket auger into the ground, typically in 6-inch increments. The soil sampling was performed in general accordance with the American Society for Testing and Materials (ASTM) test designation D-1586. The results of the pavement cores are provided in the Pavement Data Table in the Appendix.

Representative photographs of the pavement cores are also provided in the Appendix.

Tierra measured the thickness of sediment in the 54th Avenue Canal in the vicinity of the proposed sediment removal sumps and outfall structure using a total of five (5) probes.

The probes were performed by advancing a probe rod through the sediment and recording the thickness. The approximate locations and results of the probes are presented on the Sediment Probing Plan sheet in the Appendix.

The soil strata encountered in the borings performed at the project site are summarized in the following table:

Stratum Number Soil Description USCS

Classification

1 Gray to Pale Brown SAND to SAND with Silt with Occasional Shell Fragments SP/SP-SM

2 Gray Silty Sand SM 3 Dark Gray Sandy SILT with Shell Fragments ML

The subsurface soil stratification is of a generalized nature to highlight the major subsurface stratification features and material characteristics. The soil profiles included in the Appendix should be reviewed for specific information at individual boring locations.

These profiles include soil descriptions, stratifications, and penetration resistances. The stratifications shown on the boring profiles represent the conditions only at the actual boring location. Variations did occur and should be expected between boring locations. The stratifications represent the approximate boundary between subsurface soils and the actual transition may be gradual.

Groundwater Information

The groundwater table was measured at depths ranging from 4¼ to 7 feet below existing grades within the borings performed. The Soil Profiles sheets should be reviewed for specific groundwater information at each boring location.

7th Street North, 50th Avenue North and Vicinity Storm Drainage Improvements Pinellas County, Florida

It should be noted that groundwater levels tend to 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 are normally recorded during rainy seasons.

EVALUATION AND RECOMMENDATIONS

General

The results of the borings performed along the proposed pipe alignments are presented on the Soil Profiles sheets in the Appendix.

Tierra recommends utilizing the current FDOT Standard Specifications and applicable Pinellas County Specifications as guidelines for construction of the proposed storm water improvements.

Potentiometric Surface

Based on a review of the “Potentiometric Surface of the Upper Floridan Aquifer, West- Central Florida” maps published by the USGS, the potentiometric surface in the vicinity of the pipe alignments is on the order approximately +5 to +10 feet, NGVD. As previously noted, the natural ground surface elevations along the project locations are on the order of approximately +5 to +10 feet, NGVD. Artesian flow conditions were not encountered within the borings performed during the field exploration. However, the contractor should be prepared to handle a potentiometric condition of up to +10 feet, NGVD, at no additional cost to the city.

Protection of Existing Structures

Residential homes are located within close proximity of the proposed improvements.

Depending on the means and methods of construction/installation of the drainage structures, vibration concerns may become critical to the project. Heavy vibratory equipment should not be used to compact soils along the project alignment. In areas adjacent to residential structures, non-vibratory equipment may be required to prevent vibration damage.

Tierra recommends that the structures adjacent to the proposed project areas be monitored during construction. A pre-condition survey and a post-condition survey are recommended for these structures. Tierra recommends addressing the protection of existing structures within the plans by stating that it is the responsibility of the Contractor to take necessary precautions to protect existing structures and that it is the Contractor’s responsibility to repair any damage to adjacent structures caused at his expense.

7th Street North, 50th Avenue North and Vicinity Storm Drainage Improvements Pinellas County, Florida

On-Site Soil Suitability

The suitability of the soil for reuse along the project should be evaluated against the project engineering fill requirements. Variations in the subsurface stratifications should be expected between borings. Fill should be placed in accordance with current City requirements.

In general, the soils of Stratum 1 (SP/SP-SM) may be moved and used for grading purposes, site leveling, general engineering fill, and trench backfill, provided the fill is free of organic materials, clay, debris or any other material deemed unsuitable for construction and evaluated against engineering fill requirements.

Site Preparation

Prior to construction, the location of any existing underground utilities within the construction area should be established. Material suitable for re-use may be stockpiled;

however, any material stockpiled for re-use shall be tested for conformance to material specifications as indicated in the following sections of this preliminary report. Provisions should then be made to relocate any interfering utility lines within the construction area to appropriate locations and backfilling the resulting excavations with compacted structural fill.

In this regard, it should be noted that if abandoned underground pipes are not properly removed or plugged, they might serve as conduits for subsurface erosion, which subsequently may result in excessive settlement.

Drainage Structures Recommendations

Tierra has created a table of recommended soil parameters for use by the design engineer in his/her design and analysis of the proposed structures. The recommended parameters are included in the Appendix.

It is our understanding that sheet pile walls may be required to install the proposed structure. Temporary sheet piling may be utilized during excavation activities associated with construction of the outfall/culvert structure and associated endwall.

Structure foundations should bear on compacted natural sandy soils or properly placed and compacted cohesionless (sand) structural fill in accordance with City requirements.

The foundation excavations which encounter debris will require a minimum of being over-excavated to a depth of 2 to 3 feet below the proposed bottom of foundation bottom elevation and backfilled with crushed stone (FDOT No. 57 or No. 67 stone). The crushed stone should be seated to provide a relatively firm and unyielding surface. The stone shall be placed in accordance with County specifications.

7th Street North, 50th Avenue North and Vicinity Storm Drainage Improvements Pinellas County, Florida

The settlement of the proposed outfall/culvert supported on firm and unyielding crushed stone or properly compacted sand fill or natural sandy soils should occur rapidly after loading. Thus, the expected settlement should occur during construction as dead loads are imposed. Provided recommended site preparation operations are properly performed and the recommendations presented in the following sections are utilized, the total settlement of the outfall/culvert should not exceed approximately ½ inch. Differential settlement is estimated to be on the order of ½ of the total settlement. Differential settlement of this magnitude is usually considered tolerable for the anticipated construction. However, the Structural Engineer should compare the anticipated settlement to the allowable settlement of the structure to ensure that it is acceptable.

It should be noted that the recommendations provided herein were based on limited/preliminary design information provided by Land & Water Engineering. Once final design information for the box culvert/outfall structure becomes available, Tierra will revise the recommendations provided herein, as appropriate.

Drainage and Groundwater Concerns

The groundwater levels presented in this preliminary report are the levels that were measured at the time of our field activities. Fluctuation should be anticipated. We recommend that the Contractor determine the actual groundwater levels at the time of the construction to determine groundwater impact on his construction procedure. Care should be given to open excavations and site grading to minimize ponding of surface water.

Backfill

The suitability of the soil for reuse along the project should be evaluated against project requirements. Variations in the subsurface stratifications should be expected between borings. Materials to be used for fill or backfill should be evaluated and, if necessary, tested by Tierra prior to placement to determine if they are suitable for the intended use.

Excavations

Temporary side slopes and excavations should comply with the Occupational Safety and Health Administration’s (OSHA) trench safety standards, 29 C.F.R., s. 1926.650, Subpart P, subsequent revisions or updates of OSHA’s referenced standard adopted by the Department of Labor and Employment Security and Florida’s Trench Safety Act, Section 553.62, Florida Statutes. Excavated materials should not be stockpiled at the top of the slope within a horizontal distance equal to the excavation depth.

7th Street North, 50th Avenue North and Vicinity Storm Drainage Improvements Pinellas County, Florida

REPORT LIMITATIONS

The conclusions and recommendations contained in this preliminary report are opinions based on the site conditions and project layout described herein and further assume that the conditions observed in the exploratory borings are representative of the subsurface conditions throughout the site, i.e., the subsurface conditions elsewhere on the site are the same as those disclosed by the borings. If, during construction, subsurface conditions different from those encountered in the exploratory borings are observed or appear to be present beneath excavations, we should be advised at once so that we can review these conditions and reconsider our recommendations where necessary.

If there is a substantial lapse in time between the submittal of this preliminary report and the start of work at the site, or if conditions or project layout are changed due to natural causes or construction operations at or adjacent to the site, we recommend that this preliminary report be reviewed to determine the applicability of conclusions and recommendations considering the changed conditions and time lapse.

This preliminary report was prepared for the exclusive use of Land and Water Engineering Science, Inc. and their clients for evaluating the design of the project as it relates to the geotechnical aspects discussed herein. It should be made available to prospective contractors for information on factual data only and not as a warranty of subsurface conditions included in this preliminary report. Unanticipated soil conditions may require that additional expense be made to attain a properly constructed project. Therefore, some contingency fund is recommended to accommodate such potential extra costs.

Appendix

USDA Soil Survey & USGS Quadrangle Map Summary of USDA Soil Survey

Boring Location Plan Soil Profile Sheets

Sediment Probing Plan Recommended Soil Parameters

Pavement Data Table Representative Photographs of Pavement Cores

54TH AVE. N

53RD TER. N

54TH AVE. N

53RD AVE. N

54TH AVE. N

52ND AVE. N

51ST AVE.N

54TH AVE. N

52ND AVE. N

PLAN SCALE

0 1000'

CHECKED BY:

DRAWN BY:

DATE:

SCALE: PROJECT NUMBER:

ENGINEER OF RECORD:

WPR

DEC 2020

WPR

NOTED 6511-20-160

PINELLAS COUNTY, FLORIDA

GEOTECHNICAL ENGINEERING SERVICES

SHEET 1TIERRA

7351 Temple Terrace Highway Tampa, Florida 33637 Phone: 813-989-1354 Fax: 813-989-1355 FL Cert. No.: 6486

TOWNSHIP:

RANGE:

SECTION:

REFERENCE: USDA SOIL SURVEY OF PINELLAS COUNTY, FLORIDA

30S & 31 S 17 E

APPROVED BY:

APPROXIMATE

PROJECT

LOCATION

REFERENCE: "SAINT PETERSBURG, FLORIDA" USGS QUADRANGLE MAP

USDA SOIL SURVEY MAP USGS QUADRANGLE MAP

WILLIAM P. ROVIRA IV, P.E.

FLORIDA LICENSE NO.:

74586

7TH STREET NORTH, 50TH AVENUE

NORTH & VICINITY DRAINAGE IMPROVEMENTS

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SUMMARY OF USDA SOIL SURVEY

PINELLAS COUNTY, FLORIDA

USCS AASHTO Depth (feet) Months

0-42 SP, SP-SM A-3 2.0 - 6.0 6.1-8.4

42-80 SP, SP-SM A-3 6.0 - 20.0 6.1-8.4

0-8 SP, SP-SM A-3 6.0 - 20.0 6.1-8.4

8-33 SP-SM A-2-4 2.0 - 20.0 6.1-8.4

33-48 SP, SP-SM A-3 6.0 - 20.0 6.1-8.4

48-63 SM, SP-SM A-2-4 2.0 - 20.0 6.1-8.4

63-80 SP, SP-SM A-3 6.0 - 20.0 6.1-8.4

(30)

Urban land --- --- --- --- - --- --- --- ---

0-5 SP, SP-SM A-3 6.0 - 20.0 3.5-6.5

5-26 SP, SP-SM A-3 6.0 - 20.0 3.5-6.5

26-36 SM, SP-SM A-2-4, A-3 0.6 - 2.0 4.5-7.3

36-50 SC, SC-SM A-2-4, A-2-6 0.1 - 0.2 4.5-8.4

50-80 SM, SP-SM A-2-4, A-3 6.0 - 20.0 7.4-8.4

7TH STREET AND 50TH AVENUE NORTH DRAINAGE IMPROVEMENTS

(16) Matlacha- St.

Augustine- Urban land

June-Oct2.0-3.0

June-Oct1.5-3.0

(31) Wabasso- Urban land

0.5-1.5 June-Oct

USDA Map Unit and Soil

Name

Seasonal High Water Table pHDepth

(in) Permeability

(in/hr)

Soil Classification

B-3

B-1

B-2 B-2A

54TH AVE. N

53RD TER. N

54TH AVE. N

53RD AVE. N

54TH AVE. N

52ND AVE. N

51ST AVE.N

54TH AVE. N

52ND AVE. N

AB-2

AB-1

C-6

C-4

C-3

C-2

C-1

C-5

B-6

B-5

B-4

ENGINEER OF RECORD:

PROJECT NUMBER:

DATE:

SCALE:

APPROVED BY:

CHECKED BY:

DRAWN BY:

NOTE: BASE MAP PROVIDED BY LAND & WATER ENGINEERING LEGEND

PLAN SCALE

0 200'

BORING LOCATION PLAN

APPROXIMATE LOCATION OF AUGER BORING

APPROXIMATE LOCATION OF SPT BORING

TIERRA

7351 Temple Terrace Highway Tampa, Florida 33637 Phone: 813-989-1354 Fax: 813-989-1355 FL Cert. No.: 6486

WPR

DEC 2020

WPR

NOTED 6511-20-160

PINELLAS COUNTY, FLORIDA

GEOTECHNICAL ENGINEERING SERVICES

SHEET 2

WILLIAM P. ROVIRA IV, P.E.

FLORIDA LICENSE NO.:

74586

APPROXIMATE LOCATION OF PAVEMENT CORE

7TH STREET NORTH, 50TH AVENUE

NORTH & VICINITY DRAINAGE IMPROVEMENTS

AutoCAD SHX Text S

AutoCAD SHX Text D

AutoCAD SHX Text 12" Palm

AutoCAD SHX Text 12" Ear

AutoCAD SHX Text 12" Palm

AutoCAD SHX Text 6" Oak

AutoCAD SHX Text S

AutoCAD SHX Text D

AutoCAD SHX Text T

AutoCAD SHX Text S

AutoCAD SHX Text D

AutoCAD SHX Text

PBOX

AutoCAD SHX Text

PBOX

AutoCAD SHX Text D

AutoCAD SHX Text T

AutoCAD SHX Text 4" Palm

AutoCAD SHX Text

PBOX

AutoCAD SHX Text

PBOX

AutoCAD SHX Text

PBOX

AutoCAD SHX Text 4" Palm

AutoCAD SHX Text S

AutoCAD SHX Text

PBOX

AutoCAD SHX Text D

AutoCAD SHX Text

PBOX

AutoCAD SHX Text 12" Oak

AutoCAD SHX Text 3" Ficus

AutoCAD SHX Text 4" Palm

AutoCAD SHX Text D

AutoCAD SHX Text 36" Oak

AutoCAD SHX Text 14" Palm

AutoCAD SHX Text D

AutoCAD SHX Text

PBOX

AutoCAD SHX Text 14" Palm

AutoCAD SHX Text 24" Maple

AutoCAD SHX Text 60FT" Oak

AutoCAD SHX Text 12" Oak

AutoCAD SHX Text 18" Maple

AutoCAD SHX Text 5" Palm

AutoCAD SHX Text 3" Palm

AutoCAD SHX Text 3" Willow

AutoCAD SHX Text 48" Oak

AutoCAD SHX Text 6" Palm

AutoCAD SHX Text 2" Palm

AutoCAD SHX Text 12" Palm

AutoCAD SHX Text 2" Palm

AutoCAD SHX Text 18" Palm

AutoCAD SHX Text 12" Palm

AutoCAD SHX Text 24" Oak

AutoCAD SHX Text 12" Oak

AutoCAD SHX Text 6" Palm

AutoCAD SHX Text 18" Palm

AutoCAD SHX Text 24" Oak

AutoCAD SHX Text 12" Palm

AutoCAD SHX Text 2" Oak

AutoCAD SHX Text 6" Ficus

AutoCAD SHX Text 24" Oak

AutoCAD SHX Text 2" Citrus

AutoCAD SHX Text 6" Palm

AutoCAD SHX Text 4" Palm

AutoCAD SHX Text 2" Palm

AutoCAD SHX Text

FO02

AutoCAD SHX Text

FO02

AutoCAD SHX Text 24" Oak

AutoCAD SHX Text 28" Palm

AutoCAD SHX Text 18" Palm

AutoCAD SHX Text 2" Maple

AutoCAD SHX Text 7" Citrus

AutoCAD SHX Text 4" Palm

AutoCAD SHX Text " Citrus

AutoCAD SHX Text 5" Carrotwood

AutoCAD SHX Text 12 Myrtle

AutoCAD SHX Text 12" Carrotwood

AutoCAD SHX Text 6 Myrtle

AutoCAD SHX Text 36" Oak

AutoCAD SHX Text 4" Avocado

AutoCAD SHX Text 3" Maple

AutoCAD SHX Text 20" Oak

AutoCAD SHX Text 48" Oak

AutoCAD SHX Text 18" Oak

AutoCAD SHX Text 24" Brazillian Pepper

AutoCAD SHX Text 18" Oak

AutoCAD SHX Text 12" Oak

AutoCAD SHX Text 14" Ear

AutoCAD SHX Text 3" Maple

AutoCAD SHX Text 18" Palm

AutoCAD SHX Text 18" Oak

AutoCAD SHX Text 30" Oak

AutoCAD SHX Text 40" Oak

AutoCAD SHX Text 30" Oak

AutoCAD SHX Text 36" Oak

AutoCAD SHX Text D

AutoCAD SHX Text

RIM=103.67

AutoCAD SHX Text

SND

AutoCAD SHX Text T

AutoCAD SHX Text S

AutoCAD SHX Text W

ENGINEER OF RECORD:

PROJECT NUMBER:SCALE:

APPROVED BY:

DATE:

DRAWN BY:

CHECKED BY:

SOIL PROFILES

TIERRA

7351 Temple Terrace Highway Tampa, Florida 33637 Phone: 813-989-1354 Fax: 813-989-1355 FL Cert. No.: 6486

LEGEND

OF PENETRATION (UNLESS OTHERWISE NOTED)

SPT N-VALUE IN BLOWS/FOOT FOR 12 INCHES

HA HAND AUGERED TO VERIFY UTILITY CLEARANCES

12 to 24 6 to 12

24 to 40 8 to 24

(BLOWS/FT.)

SPT N-VALUE

(BLOWS/FT.)

SPT N-VALUE

GREATER THAN 24

LESS THAN 3

GREATER THAN 40

LESS THAN 1

3 to 6 1 to 3

3 to 8

15 to 30 8 to 15

30 to 50 10 to 30 4 to 10

(BLOWS/FT.)

SPT N-VALUE

(BLOWS/FT.)

SPT N-VALUE

GREATER THAN 30

LESS THAN 4

GREATER THAN 50

LESS THAN 2

VERY LOOSE

HARD

VERY STIFF

STIFF

SILTS AND CLAYS

CONSISTENCY

FIRM

SOFT

VERY SOFT

LOOSE

DENSE

VERY DENSE

4 to 8 2 to 4

RELATIVE DENSITY

GRANULAR MATERIALS-

SAFETY HAMMER

MEDIUM DENSE

AUTOMATIC HAMMER

GRAY SILTY SAND (SM)

DARK GRAY SANDY SILT WITH SHELL FRAGMENTS (ML)

PAVEMENT AND BASE MATERIAL

UNIFIED SOIL CLASSIFICATION SYSTEM (ASTM D 2488) GROUP

SYMBOL AS DETERMINED BY VISUAL REVIEW AND LABORATORY

TESTING ON SELECTED SAMPLES FOR CONFIRMATION OF VISUAL

REVIEW

ESTIMATED SEASONAL HIGH GROUNDWATER TABLE

GROUNDWATER LEVEL ENCOUNTERED DURING

INVESTIGATION

GRAY TO PALE BROWN SAND TO SAND WITH SILT WITH

OCCASIONAL SHELL FRAGMENTS (SP/SP-SM)

NOTE: BORING LOCATIONS WERE ESTIMATED BY TIERRA, INC. IN THE

FIELD USING A HAND-HELD GPS AND THEREFORE SHOULD BE

CONSIDERED APPROXIMATE

BORING TERMINATED PRIOR TO A DEPTH OF 5 FEET DUE TO

AUGER REFUSAL

EASTING

NORTHING

EASTING COORDINATE REFERENCED TO THE FLORIDA STATE

PLANE COORDINATE SYSTEM, FLORIDA WEST ZONE, N.A.D. 83

DETERMINED USING HAND-HELD GARMIN ETREX GPS EQUIPMENT

WITH A REPORTED ACCURACY OF +/- 10 FEET

NORTHING COORDINATE REFERENCED TO THE FLORIDA STATE

PLANE COORDINATE SYSTEM, FLORIDA WEST ZONE, N.A.D. 83

DETERMINED USING HAND-HELD GARMIN ETREX GPS EQUIPMENT

WITH A REPORTED ACCURACY OF +/- 10 FEET

D E

P T

F E

E T

BOR # B-1

EASTING 448965

NORTHING 1266940

DATE 12/2/2020

DRILLER K. CAUDILL

HAMMER AUTOMATIC

RIG D-25

BOR # AB-1

EASTING 448719

NORTHING 1266955

DATE 12/2/2020

BOR # B-2

EASTING 448424

NORTHING 1267307

DATE 12/2/2020

DRILLER K. CAUDILL

HAMMER AUTOMATIC

RIG D-25

BOR # B-2A

EASTING 448434

NORTHING 1267297

DATE 11/10/2020

BOR # AB-2

EASTING 448437

NORTHING 1267678

DATE 12/2/2020

D E

P T

F E

E T

BOR # B-3

EASTING 448457

NORTHING 1268127

DATE 11/10/2020

DRILLER K. CAUDILL

HAMMER AUTOMATIC

RIG D-25

BOR # B-4

EASTING 448449

NORTHING 1268206

DATE 11/10/2020

DRILLER K. CAUDILL

HAMMER AUTOMATIC

RIG D-25

BOR # B-5

EASTING 448458

NORTHING 1268357

DATE 11/10/2020

DRILLER K. CAUDILL

HAMMER AUTOMATIC

RIG D-25

BOR # B-6

EASTING 450143

NORTHING 1268200

DATE 11/10/2020

DRILLER K. CAUDILL

HAMMER AUTOMATIC

RIG D-25

D E

P T

F E

E T

D E

P T

F E

E T

WPR

DEC 2020

WPR

NOTED 6511-20-160

PINELLAS COUNTY, FLORIDA

GEOTECHNICAL ENGINEERING SERVICES

SHEET 3

WILLIAM P. ROVIRA IV, P.E.

FLORIDA LICENSE NO.:

74586

NMC

-200

LIQUID LIMIT (%)

PLASTICITY INDEX (%)

NATURAL MOISTURE CONTENT (%)

PERCENT PASSING #200 SIEVE

-200 = 9

-200 = 21

-200 = 8

-200 = 11

-200 = 5

NMC =

PI =

LL =

-200 = 57

NP NON PLASTIC

7TH STREET NORTH, 50TH AVENUE

NORTH & VICINITY DRAINAGE IMPROVEMENTS

SPT BORING B-2A

TERMINATED DUE TO

PRESENCE OF

CONCRETE

AT A DEPTH OF 6

FEET.

2, 2.5

4, 4.5

3, 5

3, 3.5 3, 5.5

ENGINEER OF RECORD:

PROJECT NUMBER:

DATE:

SCALE:

APPROVED BY:

CHECKED BY:

DRAWN BY:

LEGEND

PLAN SCALE

0 50'

SEDIMENT PROBING PLANS

TIERRA

7351 Temple Terrace Highway Tampa, Florida 33637 Phone: 813-989-1354 Fax: 813-989-1355 FL Cert. No.: 6486

WPR

DEC 2020

WPR

NOTED 6511-20-160

PINELLAS COUNTY, FLORIDA

GEOTECHNICAL ENGINEERING SERVICES

SHEET 4

WILLIAM P. ROVIRA IV, P.E.

FLORIDA LICENSE NO.:

74586

APPROXIMATE PROBE LOCATION

MEASURED WATER DEPTH OF 3 FEET, 7 FEET OF SOFT SEDIMENT BELOW MUDLINE

3, 7

NOTE:

PROBE LOCATIONS SHOULD BE CONSIDERED APPROXIMATE AND WERE BASED

ON HAND-HELD GPS DEVICES WITH A MANUFACTURER’S REPORTED ACCURACY

OF ± 10 FEET. WATER DEPTHS SHOULD BE CONSIDERED APPROXIMATE AND

REFLECT THE WATER LEVELS DURING FIELD ACTIVITIES IN DECEMBER 2020. PROBING

WAS PERFORMED BY MANUALLY PUSHING A PROBE ROD BELOW THE MUDLINE

THROUGH THE SOFT SEDIMENT LAYER UNTIL A FIRM LAYER WAS ENCOUNTERED.

THE THICKNESS OF THE SOFT SEDIMENT LAYER SHOULD BE CONSIDERED

QUALITATIVE.

7TH STREET NORTH, 50TH AVENUE

NORTH & VICINITY DRAINAGE IMPROVEMENTS

AutoCAD SHX Text S

AutoCAD SHX Text 12" Palm

AutoCAD SHX Text 12" Ear

AutoCAD SHX Text 12" Palm

6" Oak

Total Dry Total Wet Effective

0 to 13 SP/SP-SM/SM HA to 9 100 105 43 29 0

13 to 18 SP/SP-SM/SM 3 97 102 40 28 0

18 to 28 SP/SP-SM/SM 18 to 29 110 115 53 32 0

28 to 35 ML 5 to 9 110 115 53 29 0

(2) Assumes proper subgrade preparation in accordance with City Specifications and this geotechnical report

Depth (ft.) Soil Type SPT N Range Soil Total Unit Weight (pcf) Angle of

Internal Friction

(degrees)

Cohesion (Su) (psf)

(1) Pressure Coefficients based on flat/non-sloping ground

RECOMMENDED SOIL PARAMETERS - STORMWATER OUTFALL/CULVERT (BORING B-4)

Modulus of Subgrade

Reaction(2)

(pci)

Allowable Bearing

Capacity(2)

(psf)

25 2000

Top Layer

Bottom Layer

Top Layer

Bottom Layer

C-1 449559 1266942 1.4 -- SP-12.5 1.4 Soil Cement with Shell 4.3 0.6" Crack

C-2 448420 1267002 2.0 -- SP-12.5 2.0 Shell 4.0 Full Depth Crack

C-3 448392 1267228 0.6 0.9 SP-9.5 S-3 1.5 Shell 6.3 Full Depth Crack

C-4 448422 1267500 1.9 -- SP-12.5 1.9 Shell 5.1

C-5 448394 1267818 1.5 1.6 S-1 S-3 3.1 Shell 5.0 Full Depth Crack

C-6 448424 1268071 1.5 -- SP-12.5 1.5 Shell 4.8 Full Depth Crack

± 10 feet and therefore should be considered approximate. GPS coordinates provided are refrenced to the Florida State Plane West coordinate system.

Northing

(1) Pavement core locations were estimated in the field by a representative of Tierra using a non-survey grade GPS unit with a reported accuracy of

Comments

Type Thickness (inches)

Core No.

Base for Paved Roadway

Total Asphalt Core Length

(inches)

Pinellas County, Florida Tierra Project Number: 6511-20-160

Location(1)

(2) Pavement layer identification based on visual review using FDOT nomenclature. Actual pavement layer may be a local mix. Pavement layers are classified in decending order from the top of the core sample to the bottom.

Notes:

Pavement Data Table 7th Street and 50th Avenue North Drainage Improvements

Easting

Thickness (inches) Type(2)

Asphalt Layer

Photographs of Pavement Cores 7th Street and 50th Avenue North Drainage Improvements

Pinellas County, Florida Tierra Project No.: 6511-20-160

Pavement Core C-1

Pavement Core C-2

Pavement Core C-3

Pavement Core C-4

Pavement Core C-5

Pavement Core C-6

PROJECT DESCRIPTION

Project Information

Scope of Services/Objectives

SITE AND SUBSURFACE CONDITIONS

General Site Information

USGS Quadrangle Maps

Pinellas County Soil Survey

Subsurface Conditions

Groundwater Information

Soil Description

EVALUATION AND RECOMMENDATIONS

General

Potentiometric Surface

Protection of Existing Structures

On-Site Soil Suitability

Site Preparation

Drainage Structures Recommendations

Drainage and Groundwater Concerns

Backfill

Excavations

REPORT LIMITATIONS

6511-20-160.pdf

Sheets and Views

6511-20-160-USDA_USGS

6511-20-160-BLP

6511-20-160-SOIL PROFILE

6511-20-160-SEDIMENT PROBING PLAN

65654.pdf

Table

Pavement Data Sheet.pdf

PVT SURVEY SHEET

File details come from the government source that posted it. Updated Sep 23, 2025.