DRAFT Geotechnical Technical Memorandum

Transcription

1 DRAFT Geotechnical Technical Memorandum US 19 (SR 55) Reevaluation from 66 th Avenue North to SR 690/118 th Avenue North Work Program Item Segment No Project Development and Environment Study Florida Department of Transportation District Seven September 20 TIERRA, Inc Temple Terrace Highway Tampa, Florida Phone (813) Fax (813) Florida Certificate No. 6486

2 September 6, 20 H.W. Lochner, Inc W. Cypress Street, Suite 800 Tampa, FL Attn: RE: Mr. William G. Howell, P.E. Geotechnical Technical Memorandum US 19 (SR 55) from from 66 th Avenue to 118 th Avenue North Tierra Project No Mr. Howell: Tierra, Inc. (Tierra) has completed Geotechnical Engineering Services for the referenced project. The results of the study are enclosed herein. Tierra appreciates the opportunity to provide our services to H.W. Lochner, Inc (Lochner) and the Florida Department of Transportation (FDOT) on this project. If you have any questions regarding this report, please contact us at (813) Respectfully Submitted, TIERRA, INC. Susan E. Fries Geotechnical Engineer Intern Larry P. Moore, P.E. Principal Geotechnical Engineer Florida License No TIERRA, Inc Temple Terrace Highway Tampa, Florida Phone (813) Fax (813) Florida Certificate No. 6486

3 Table of Contents 1.0 INTRODUCTION Need for Improvement Purpose of Report PROJECT DESCRIPTION Existing Conditions Alternatives Considered SUBSURFACE CONDITIONS Pinellas County Soil Survey Anclote Fine Sand (Unit 3) Felda Soils and Urban Land (Unit ) Felda Fine Sand (Unit ) Manatee Loamy Fine Sand (Unit ) Matlacha and St. Augustine Soils and Urban land (Unit ) Myakka Soils and Urban Land (Unit ) Okeechobee Muck (Unit 18) Pineda Soils and Urban Land (Unit ) Pinellas Soils and Urban Land (Unit ) Urban Land (Unit 30) Wabasso Soils Urban Land (Unit ) General Soil Properties Groundwater Conditions PRELIMINARY ENGINEERING EVALUATIONS General Shallow Groundwater Near Surface Clayey Soils Organic Soils Roadway Construction LIMITATIONS List of Tables 3-1 & 3-2 Pinellas County USDA NRCS Soil Survey Information List of Figures Project Location Map USDA Soil Survey i

4 Tierra Project No Page 1 of INTRODUCTION The Florida Department of Transportation (FDOT) is conducting a reevaluation of the Finding of No Significant Impact (FONSI) environmental document approved by the Federal Highway Administration (FHWA) on May 7, for the Project Development and Environment (PD&E) Study for US 19 (State Road (SR) 55) from Gandy Boulevard (SR 694) in Pinellas County to Alternate US 19 (SR 595) in Pasco County, Florida. The project limits for this reevaluation will extend south of the original PD&E study limits to 66th Avenue North and north to 118th Avenue North (SR 690), a distance of approximately 3.8 miles shown in Figure 1. The objective of the PD&E reevaluation study is to provide documented environmental and engineering analyses that will assist the FDOT in reaching a decision on the location and conceptual design for improvements to US 19. This Study will also comply with the requirements of the National Environmental Policy Act (NEPA) and other Federal laws to qualify the proposed project for Federal-aid funding. This reevaluation is required to maintain eligibility for future federal funding due to the length of time that has passed since the original environmental document was approved. The reevaluation will document what changes have occurred within the project limits, to determine whether the environmental document remains valid or additional analysis is needed. These may include: changes in the design or scope of the project; new or modified laws and regulations, circumstances or project area changes; or other new information affecting the project. To support the reevaluation, Tierra has completed this Geotechnical Memorandum to summarize the soil and groundwater conditions along the limits of the project.

5 Tierra Project No Page 2 of 13 Figure 1: Project Location Map

6 Tierra Project No Page 3 of Need for Improvement The primary purpose of this project is to increase capacity and improve operations and safety along US 19 (SR 55) from 66 th Avenue North to 118 th Avenue North (SR 690) in Pinellas County, Florida, to accommodate the projected increase in future traffic volumes, including the large number of commuters traveling within the corridor. The project includes increasing the capacity and improving the operations of the interchange at US 19 and Gandy Boulevard / Park Boulevard (SR 694). This project will also improve the accessibility, mobility and safety of US 19 for non-motorized users, including pedestrians, bicyclists and transit patrons. Several factors contribute to the need to examine capacity and other improvements along this corridor. US 19 is the only continuous north-south, general land service highway serving the populous Pinellas / Pasco County area. US 19 also serves the western edge of the Gateway Business District, which is a large employment and activity center within Pinellas County. As such, this facility has been identified as having a key role in providing mobility for people and goods traveling through Pinellas County, and it provides key linkages to major and minor cities within the County (Clearwater, St. Petersburg, Pinellas Park, Largo, Tarpon Springs, etc.) and to Pasco and Manatee Counties to the north and south, respectively. The proposed improvements will improve traffic operations now and in the future to allow this facility to operate safely and reduce delays. Additionally, US 19 is designated as an evacuation route by the Florida Division of Emergency Management and is an important south to north connector that will provide mobility for the evacuation of people and emergency service responders in a time of need. 1.2 Purpose of Report The purpose of the geotechnical portion of the PD&E study is to obtain information on the existing subsurface conditions along the project alignment to assist in the preparation of the PD&E Report for the project. The following services were provided to achieve the preceding objective: 1. Reviewed published soils information. This published information was obtained from the Web Soil Survey of published by the USDA NRCS. 2. Prepared this Geotechnical Technical Memorandum for the project. 2.1 Existing Conditions 2.0 PROJECT DESCRIPTION The US 19 corridor is a north/south facility with a functional classification of urban principal arterial. The project is located within Sections, 21,, 26, 27, 34 and 35 of Township 30 South, Range East in Pinellas County. In its existing condition, US 19 includes four typical sections within the project limits: US 19 from 66 th Avenue North to Gandy Boulevard is a six-lane divided facility with three -foot lanes in each direction, Type-F curb and gutter, and five-foot sidewalks. US 19 from Gandy Boulevard to 78 th Street North is a six-lane divided facility with three 11-foot lanes in each direction, four-foot bike lanes, Type-F curb and gutter, and five-foot sidewalks.

7 Tierra Project No Page 4 of 13 US 19 from 78 th Avenue North to 49 th Street North is a six-lane divided facility with a raised curbed median, three -foot lanes in each direction, -foot outside shoulders (5-foot paved), and five-foot sidewalks. US 19 from 49 th Street North to 118 th Avenue North is a six-lane divided facility with twolane frontage roads in both directions. The mainline includes a concrete median barrier, three 11-foot travel lanes in each direction with 8-foot inside shoulders and -foot outside shoulders. The roadway becomes elevated with retaining wall and grade separated overpasses and bridges at 1 th Avenue North, and 118 th Avenue North. The frontage roads provide one -foot lane, one 11-foot lane, a 3-foot undesignated bike lane and a 6-foot sidewalk. The posted speed limit along the southern portion of the corridor is 45 miles per hour (mph), increasing to 50 mph at 82 nd Avenue North, and then increasing again to 55 mph at Gateway Center Boulevard for the remainder of the study area. Existing frontage roads are posted at 35 mph. The existing right-of-way (ROW) is generally 0 feet wide from 66 th Avenue North to 78 th Avenue North and then 200 feet wide to the north. At the 49 th Street North interchange, the ROW widens to a maximum of 440 feet within the interchange. There is a diverse mixture of existing land uses along and adjacent to US 19 within the project limits. The majority of the area within a one-mile buffer surrounding the corridor is fully developed; and consists primarily of commercial land uses with a few residential areas scattered throughout. Residential land use is primarily offset from the roadway except for the section north of Mainlands Boulevard where the residential communities are located closer to the mainline. 2.2 Alternatives Considered No-Build Alternative The No-Build Alternative assumes that no action will be taken to improve US 19 within the project limits. This involves leaving the existing roadway as it is, with only routine maintenance as required. Advantages of the No-Build Alternative include: No construction costs; No disruption to traffic due to construction; No disruption to the adjacent property owners due to construction; No ROW acquisitions or relocations; and No degradation or disruption of natural and other environmental resources due to construction. Disadvantages of the No-Build Alternative include: Increased traffic congestion causing increased road user costs due to travel delay; Not consistent with the local transportation plans; Increased potential for vehicular crashes due to congested lanes and intersections; Increased emergency vehicle response times; Increased potential for crashes between vehicles and pedestrians / bicycles due to inadequate sidewalks and bicycle lanes; and Increased vehicle emission pollutants due to higher levels of traffic congestion. The No-Build Alternative will remain a viable alternative throughout this PD&E Reevaluation Study.

8 Tierra Project No Page 5 of 13 Build Alternatives Considered Three Build alternatives were considered as part of this reevaluation study: Alternative 1: Modified FONSI. This alternative updates the preferred alternative from the original approved FONSI and the 2005 reevaluation (for reconstruction of the segment from north of 49 th Street North to south of 6 th Avenue North under Financial Project Number ), to accommodate forecasted 2045 traffic volumes, and takes into account development and changed conditions that have occurred since the FONSI was approved. The alternative also addresses deficiencies at the Gandy Boulevard interchange in its current configuration and addresses capacity needs along US 19 south of the interchange and along the Gandy/Park Boulevard approaches to the interchange. Alternative 2: US 19 over Gandy Boulevard. This alternative updates the preferred alternative from the original approved FONSI and the 2005 reevaluation with new overpasses at Gateway Center Boulevard and Mainlands Boulevard and additionally develops a new interchange at Gandy/Park Boulevard by extending the expressway/frontage road concept further south through the Gandy interchange. The existing Gandy Boulevard bridge is removed and replaced with a new bridge carrying US 19 over Gandy Boulevard. Alternative 3: Gandy Boulevard over US 19. This alternative addresses deficiencies at the Gandy Boulevard interchange in its current configuration and addresses capacity needs along US 19 south of the interchange and along Gandy/Park Boulevard. The existing atgrade configuration is retained along US 19 between Gandy Boulevard and the existing 49 th Street North interchange. One additional new traffic signal at Gateway Center Drive is proposed. Proposed Improvements The proposed improvements address the anticipated future capacity needs along US 19 within the project limits and at the Gandy Boulevard interchange, including the Gandy Boulevard/Park Boulevard approaches and existing frontage roads. The expressway/frontage road concept included in the approved FONSI () from 78 th Avenue North to the 49 th Street North interchange is not included in this alternative and that section of roadway is proposed to remain at-grade. The proposed improvements tie into the previously reconstructed segment from north of 49 th Street North to south of 6 th Avenue North under Financial Project Number , and include the following: From 66 th Avenue North to 70 th Avenue North, the existing 6-lane roadway is widened to an 8- lane typical section (three (3) 11-foot travel lanes plus one 11-foot auxiliary lane in each direction), with 7-foot buffered bicycle lanes and 6-foot sidewalks in each direction. From Gandy Boulevard to 80 th Avenue North, there are three 11-foot travel lanes in each direction, plus a southbound auxiliary lane, with 7-foot buffered bike lanes and 6-foot sidewalks. Proposed improvements at the Gandy/Park Boulevard interchange, include the following features: o Construction of one additional westbound auxiliary lane from 40 th Street North to 43 rd Street North. The bridge over US 19 will accommodate six (6) 11-foot travel lanes (three (3) in each direction).

9 Tierra Project No Page 6 of 13 o Frontage roads approaching and departing the Single Point Urban Interchange (SPUI) are widened to accommodate the additional turn lanes at the SPUI intersection. o Additional turn lanes along the US 19 approaches. Additional minor improvements are also recommended at several intersections throughout the project limits including US 19 at 70 th Avenue North, and 80 th Avenue North; a new signal is proposed at Gateway Center Boulevard. The following sections evaluate the contamination/hazardous material impacts of the proposed improvements. 3.1 Pinellas County Soil Survey 3.0 SUBSURFACE CONDITIONS Based on a review of the Pinellas County Soil Survey published by the USDA-NRCS, it appears that there are eleven (11) soil-mapping units noted within the project limits. A detailed soil survey map is shown on the USDA Soil Survey in the attachments. The general soil descriptions are presented in the sub-sections below, as described in the Web Soil Survey Anclote Fine Sand (Unit 3) The Anclote component makes up 95 percent of the map unit. Slopes are 0 to 1 percent. This component is on drainageways on marine terraces on coastal plains, depressions on marine terraces on coastal plains. The parent material consists of sandy marine deposits. Depth to a root restrictive layer is greater than 60 inches. The natural drainage class is very poorly drained. Water movement in the most restrictive layer is high. Available water to a depth of 60 inches is low. Shrink-swell potential is low. This soil is not flooded. It is frequently ponded. A seasonal zone of water saturation is at 0 inches during June, July, August, September, October, November, and December. Organic matter content in the surface horizon is about 6 percent Felda Soils and Urban Land (Unit ) The EauGallie component makes up 50 percent of the map unit. Slopes are 0 to 2 percent. This component is on flatwoods on marine terraces on coastal plains. The parent material consists of sandy and loamy marine deposits. Depth to a root restrictive layer is greater than 60 inches. The natural drainage class is poorly drained. Water movement in the most restrictive layer is moderately low. Available water to a depth of 60 inches is moderate. Shrink-swell potential is low. This soil is not flooded. It is not ponded. A seasonal zone of water saturation is at inches during June, July, August, September, and October. Organic matter content in the surface horizon is about 5 percent Felda Fine Sand (Unit ) The Felda component makes up 75 percent of the map unit. Slopes are 0 to 2 percent. This component is on depressions on marine terraces on coastal plains. The parent material consists of sandy and loamy marine deposits. Depth to a root restrictive layer is

10 Tierra Project No Page 7 of 13 greater than 60 inches. The natural drainage class is very poorly drained. Water movement in the most restrictive layer is moderately high. Available water to a depth of 60 inches is low. Shrink-swell potential is low. This soil is not flooded. It is frequently ponded. A seasonal zone of water saturation is at 0 inches during June, July, August, and September. Organic matter content in the surface horizon is about 2 percent Manatee Loamy Fine Sand (Unit ) The Manatee component makes up 90 percent of the map unit. Slopes are 0 to 1 percent. This component is on drainageways on marine terraces on coastal plains, depressions on marine terraces on coastal plains. The parent material consists of sandy and loamy marine deposits. Depth to a root restrictive layer is greater than 60 inches. The natural drainage class is very poorly drained. Water movement in the most restrictive layer is moderately high. Available water to a depth of 60 inches is moderate. Shrink-swell potential is low. This soil is not flooded. It is not ponded. A seasonal zone of water saturation is at 1 inches during June, July, August, September, and October. Organic matter content in the surface horizon is about 7 percent Matlacha and St. Augustine Soils and Urban land (Unit ) The Matlacha component makes up 32 percent of the map unit. Slopes are 0 to 2 percent. This component is on fills on ridges on marine terraces on coastal plains. The parent material consists of sandy mine spoil or earthy fill. Depth to a root restrictive layer is greater than 60 inches. The natural drainage class is somewhat poorly drained. Water movement in the most restrictive layer is high. Available water to a depth of 60 inches is low. Shrink-swell potential is low. This soil is not flooded. It is not ponded. A seasonal zone of water saturation is at 30 inches during June, July, August, September, and October. Organic matter content in the surface horizon is about 0 percent. The St. Augustine component makes up 32 percent of the map unit. Slopes are 0 to 2 percent. This component is on ridges on marine terraces on coastal plains. The parent material consists of sandy mine spoil or earthy fill. Depth to a root restrictive layer is greater than 60 inches. The natural drainage class is somewhat poorly drained. Water movement in the most restrictive layer is high. Available water to a depth of 60 inches is low. Shrink-swell potential is low. This soil is not flooded. It is not ponded. A seasonal zone of water saturation is at 27 inches during June, July, August, September, and October. Organic matter content in the surface horizon is about 2 percent Myakka Soils and Urban Land (Unit ) The Myakka component makes up 50 percent of the map unit. Slopes are 0 to 2 percent. This component is on flatwoods on marine terraces on coastal plains. The parent material consists of sandy marine deposits. Depth to a root restrictive layer is greater than 60 inches. The natural drainage class is poorly drained. Water movement in the most restrictive layer is moderately high. Available water to a depth of 60 inches is low. Shrink-swell potential is low. This soil is not flooded. It is not ponded. A seasonal zone of water saturation is at inches during June, July, August, September, October, and November. Organic matter content in the surface horizon is about 4 percent.

11 Tierra Project No Page 8 of Okeechobee Muck (Unit 18) The Okeechobee component makes up 95 percent of the map unit. Slopes are 0 to 1 percent. This component is on depressions on marine terraces on coastal plains, drainageways on marine terraces on coastal plains. The parent material consists of herbaceous organic material. Depth to a root restrictive layer is greater than 60 inches. The natural drainage class is very poorly drained. Water movement in the most restrictive layer is high. Available water to a depth of 60 inches is very high. Shrink-swell potential is low. This soil is not flooded. It is frequently ponded. A seasonal zone of water saturation is at 0 inches during June, July, August, and September. Organic matter content in the surface horizon is about 80 percent Pineda Soils and Urban Land (Unit ) The Pineda component makes up 45 percent of the map unit. Slopes are 0 to 2 percent. This component is on flats on marine terraces on coastal plains. The parent material consists of sandy and loamy marine deposits. Depth to a root restrictive layer is greater than 60 inches. The natural drainage class is poorly drained. Water movement in the most restrictive layer is moderately low. Available water to a depth of 60 inches is low. Shrink-swell potential is low. This soil is not flooded. It is not ponded. A seasonal zone of water saturation is at 0 inches during July, August, and September. Organic matter content in the surface horizon is about 3 percent Pinellas Soils and Urban Land (Unit ) The Pinellas component makes up 50 percent of the map unit. Slopes are 0 to 2 percent. This component is on flats on marine terraces on coastal plains. The parent material consists of sandy and loamy marine deposits. Depth to a root restrictive layer is greater than 60 inches. The natural drainage class is poorly drained. Water movement in the most restrictive layer is moderately high. Available water to a depth of 60 inches is low. Shrink-swell potential is low. This soil is not flooded. It is not ponded. A seasonal zone of water saturation is at inches during June, July, August, September, and October. Organic matter content in the surface horizon is about 2 percent Urban Land (Unit 30) Generated brief soil descriptions are created for major soil components. The Urban land is a miscellaneous area Wabasso Soils Urban Land (Unit ) The Wabasso component makes up 50 percent of the map unit. Slopes are 0 to 2 percent. This component is on flatwoods on marine terraces on coastal plains. The parent material consists of sandy and loamy marine deposits. Depth to a root restrictive layer is greater than 60 inches. The natural drainage class is poorly drained. Water movement in the most restrictive layer is moderately low. Available water to a depth of 60 inches is low. Shrink-swell potential is low. This soil is not flooded. It is not ponded. A seasonal zone of water saturation is at inches during June, July, August, September, and October. Organic matter content in the surface horizon is about 2 percent.

12 Tierra Project No Page 9 of General Soil Properties Additional information regarding the soils and groundwater conditions for the above soil mapping units was obtained from the Pinellas County Soil Survey published by USDA-NRCS and the Web Soil Survey and is presented in Tables 3-1 and 3-2 as follows: Table 3-1 Pinellas County USDA NRCS Soil Survey Information Map No. Soil Name Hydrologic Soil Group Depth to High Water Table (ft) Typical Soil Types (Profile from Ground Surface to depth of approximately 80 inches) 3 Anclote Fine Sand D 0.0 Fine Sand EauGallie Soils Fine Sand to Sandy Clay Loam to B/D and Urban Land Sand Felda Fine Sand D Fine Sand to Fine Sandy Loam to Loamy Fine Sand Manatee Loamy Fine Loamy Fine Sand to Fine Sandy Loam B/D Sand to Fine Sand Matlacha and Sand to Fine Sand, , St. Augustine Soils C Sand to Loamy Sand to Fine Sand to and Urban Land Sandy Loam Myakka Soils and Urban Land B/D Fine Sand 18 Okeechobee Muck B/D Black Muck to Brown Mucky Peat Pineda Soils and Urban Land Pinellas Soils and Urban Land B/D Fine Sand to Fine Sandy Loam B/D Fine Sand to Fine Sandy Loam to Sand 30 Urban Land Wabasso Soils Urban Land D Fine Sand to Fine Sandy Clay Loam to Fine Sand

13 Tierra Project No Page of 13 Table 3-2 Pinellas County USDA NRCS Soil Survey Information USDA Map Symbol and Soil Name (3) Anclote () EauGallie-Urban Land () Felda () Manatee () Matlacha- St. Augustine- Urban land () Myakka-Urban Land (18) Okeechobee Depth (in) USCS Soil Classification AASHTO Permeability (in/hr) 0- SP, SP-SM A-2-4, A SM, SP, SP-SM A-2-4, A SP, SP-SM A SM, SP-SM A-2-4, A SP, SP-SM A-2-4, A SM, SP-SM A-2-4, A SC, SC-SM, SM A-2-4, A SM, SP-SM A-2-4, A SP, SP-SM A SP, SP-SM A SC, SC-SM, SM A SC-SM, SM A-2-4, A SM, SP-SM A-2-4, A SM, SP-SM A-2-4, A SC, SC-SM A SC, SC-SM, SM A SC, SC-SM, SM A SP, SP-SM A SP, SP-SM A SP, SP-SM A SP-SM A SP, SP-SM A SM, SP-SM A SP, SP-SM A SP, SP-SM A SP, SP-SM A SM, SP-SM A-2-4, A SP, SP-SM A PT A PT A

14 Tierra Project No Page 11 of 13 Table 3-2 (Continued) Pinellas County USDA NRCS Soil Survey Information USDA Map Symbol and Soil Name () Pineda-Urban Land () Pinellas-Urban Land (30) Urban land () Wabasso-Urban land Depth (in) USCS Soil Classification AASHTO Permeability (in/hr) 0-4 SP, SP-SM A SP, SP-SM A SC, SC-SM, SM A-2-4, A SM, SP, SP-SM A-2-4, A SP A SP A SP-SM A-2-4, A SC, SC-SM A-2-4, A SP, SP-SM A-2-4, A SP, SP-SM A SP, SP-SM A SM, SP-SM A-2-4, A SC, SC-SM A-2-4, A SM, SP-SM A-2-4, A Groundwater Conditions According to the USDA-NRSC Soil Survey, much of the project corridor consists of somewhat poorly to very poorly drained soils. Developed land consisting of commercial land uses with few residential areas scattered throughout exist along the project corridor. The natural seasonal high groundwater table is near the ground surface to a depth of about one to two feet throughout much of the corridor. 4.1 General 4.0 PRELIMINARY ENGINEERING EVALUATIONS Based upon the USDA-NRCS Soil Survey for Pinellas County, sandy soils and clayey sands are reported along the majority of the project corridor to depths of 80 inches below the natural ground surface. In general, the sandy soils are suitable for supporting proposed roadway embankments after proper subgrade preparation and removal of unsuitable materials. Areas along the project corridor where clay, muck and/or groundwater conditions may impact the project are detailed below.

15 Tierra Project No Page of Shallow Groundwater The SHGWT for the soil units presented above is reported to range from the predevelopment natural grade to a depth of 3 feet below the predevelopment natural grade within the project limits. Roadway base to groundwater clearance will need to be evaluated to ensure minimum separation between the base and the SHGWT is maintained or to determine if additional measures are required (ie, blackbase, underdrains, etc.). In areas where the existing SHGWT is above grade, the SHWGT will have to be established by the project biologist utilizing biological indicators Near Surface Clayey Soils The following soil mapping units noted plastic/clayey soils (A-2-6) at reported depths within 36 to 40 inches of natural grades: Pineda-Urban Land (Unit ) Pinellas-Urban Land (Unit ) Wabasso-Urban Land (Unit ) Plastic soils have limitations related to base clearance and are also poorly drained. Separation between plastic clayey soils and the roadway pavement sections should be in accordance with FDOT Standard Indices 500 and 505. As the project progresses beyond the PD&E stage, additional geotechnical services should be performed to determine the impact these materials will have to the proposed design Organic Soils Organic soils are reported in small pockets at an isolated area in the vicinity of the project alignment according to the USDA Soil Survey. The following soil mapping unit noted organic/muck (A-8) soils within 0 to 80 inches below the ground surface at an isolated area in the vicinity of the project alignment: Okeechobee Muck (Unit 18) Organic/muck (A-8) soil, if encountered during construction, should be removed in accordance with FDOT Standard Index 500 and replaced with backfill in accordance with Index 505. As the project progresses beyond the PD&E phase, delineation of the locations identified by the USDA Soil Survey as potentially containing organic soils will be required to determine the impact of the organic soils on the proposed design. Additional geotechnical services should be performed to identify the vertical and horizontal limits of the organic soils within the project limits.

16 Tierra Project No Page 13 of Roadway Construction Site preparation should consist of normal clearing and grubbing followed by compaction of subgrade soils. Subgrade preparation should include the removal of plastic soils, top-soils and organic soils in accordance with FDOT Design Standard Index 500. Backfill embankment materials should consist of materials conforming to FDOT Design Standard Index 505. Clearing and grubbing and compaction should be accomplished in accordance with the latest FDOT Standard Specifications. The overall site preparation and mechanical densification work for the construction of the proposed roadway improvements should be in accordance with the FDOT Standard Specifications and Standard Index requirements. In general, the existing subsurface soils appear capable of supporting the construction of the proposed roadway improvements subject to the above geotechnical considerations and after proper subgrade preparation. 5.0 LIMITATIONS Our professional services have been performed, our findings obtained and our preliminary evaluations prepared in accordance with generally accepted geotechnical engineering principles and practices at the time of this report. Tierra is not responsible for the conclusions, opinions or recommendations made by others based on this data. The scope of the geotechnical portion of the PD&E study is to provide information on the existing subsurface conditions along the project alignment based on a review of the Pinellas County Soil Survey published by the USDA-NRCS to assist in the preparation of the PD&E Report for the project. The preliminary evaluations submitted in this report are based upon the data obtained from the published information. Should subsoil variations become evident during the course of this project, a re-evaluation will be necessary after we have had an opportunity to observe the characteristics of the condition 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 roadway construction.

17 N 30 PROJECT LIMIT 3 GANDY BLVD. PROJECT LIMIT PROJECT LIMIT Feet BRYAN DAIRY RD TH AVE. PROJECT LIMIT US 19 (SR 55) TH STREET TH AVE. N REFERENCE: USDA SOIL SURVEY OF PINELLAS COUNTY, FLORIDA TOWNSHIP: RANGE: SECTION: 30S E, 21,, 26, 27, 34, 35 DATE DESCRIPTION REVISIONS DATE DESCRIPTION LAWRENCE P. MOORE, P.E. P.E. LICENSE NUMBER TIERRA, INC TEMPLE TERRACE HIGHWAY STATE OF FLORIDA DEPARTMENT OF TRANSPORTATION ROAD NO. COUNTY FINANCIAL PROJECT ID USDA SOIL SURVEY MAP SHEET NO. TAMPA, FLORIDA CERTIFICATE OF AUTHORIZATION NO SR 55 PINELLAS bsawaska 9/6/20 1:54:06 PM J:\6511\20 Files\ US 19 PDE\Microstation\USDA01.dgn