100% Report of Geotechnical Engineering Investigation CENTRAL FLORIDA COMMUTER RAIL TRANSIT SUNRAIL PHASE 2 SOUTH Poinciana Vehicle Storage & Light

Transcription

1 100% Report of Geotechnical Engineering Investigation CENTRAL FLORIDA COMMUTER RAIL TRANSIT SUNRAIL PHASE 2 SOUTH Poinciana Vehicle Storage & Light Maintenance Facility (VSLMF) Osceola County, Florida Financial Project ID GEC Project No. 2135G6

2 December 22, 2014 AECOM 300 Colonial Center Parkway, Suite 130 Lake Mary, Florida Attention: Subject: Mr. George Gault, P.E. Project Manager 100% Report of Geotechnical Engineering Investigation CENTRAL FLORIDA COMMUTER RAIL TRANSIT SUNRAIL PHASE 2 SOUTH Poinciana Vehicle Storage and Light Maintenance Facility (VSLMF) Financial Project No Osceola County, Florida GEC Project No. 2135G6 Dear Mr. Gault: Geotechnical and Environmental Consultants, Inc. (GEC) is pleased to present this 100% Report of Geotechnical Investigation for the above referenced project. The purpose of this study was to explore subsurface conditions at the proposed Poinciana Vehicle Storage and Light Maintenance Facility (VSLMF) location and to use the information obtained to develop geotechnical engineering recommendations to guide design of the proposed track, structures and paved drive and parking areas. This report presents the results of our field investigation and includes our recommendations regarding the geotechnical engineering aspects of the project. The recommendations in this report are based on the project information provided by AECOM to date, and should be re-evaluated if project plans change. GEC appreciates the opportunity to be of service to you on this project. If you should have any questions concerning the contents of this report, or if we may be of further assistance to you, please contact us.

3 Very truly yours, GEOTECHNICAL AND ENVIRONMENTAL CONSULTANTS, INC Michigan Avenue, Suite D Kissimmee, Florida Certificate of Authorization No Craig G. Ballock, P.E. Senior Geotechnical Engineer Gary L. Kuhns, P.E. President cc: Mr. Tharwat Hannadawod FDOT Geotechnical Project Manager GEC Project No. 2135G6 ii 100% Report of Geotechnical Engineering Investigation SunRail Phase 2 South Poinciana VSLMF

4 TABLE OF CONTENTS 1.0 SITE AND PROJECT DESCRIPTION NRCS SOIL SURVEY AND POTENTIOMETRIC SURFACE MAPS REVIEW SUBSURFACE EXPLORATION SPT Borings Machine Auger Borings Hand Auger Borings Groundwater Measurement LABORATORY TESTING DESCRIPTION OF SUBSURFACE CONDITIONS Pavement and Track Auger Boring Results Track SPT Boring Results VSLMF Building SPT Boring Results Groundwater Levels ANALYSIS AND DESIGN RECOMMENDATIONS Site Preparation Track Embankment Pavements Foundations Temporary Excavations Temporary Dewatering USE OF THIS REPORT GEC Project No. 2135G6 iii 100% Report of Geotechnical Engineering Investigation SunRail Phase 2 South Poinciana VSLMF

5 FIGURES Figure 1: USGS Quadrangle and NRCS Soil Survey Maps Figures 2A 2D: Boring Location Plan Figure 3: Soil Survey Figure 4 5: Track Auger Boring Results Figure 6: Track SPT Boring Results TABLES Table 6: Summary of Laboratory Test Results GEC Project No. 2135G6 iv 100% Report of Geotechnical Engineering Investigation SunRail Phase 2 South Poinciana VSLMF

6 1.0 SITE AND PROJECT DESCRIPTION Geotechnical and Environmental Consultants, Inc. (GEC) has been retained by AECOM, on behalf of the Florida Department of Transportation (FDOT), to provide geotechnical services for the Central Florida Commuter Rail Transit (CFCRT), SunRail Phase 2 South Project. The overall project (Phases 1 and 2) begins at the proposed Debary Saxon Road Station and ends at the proposed Poinciana Station, a total distance of about 54 miles. GEC performed the geotechnical engineering investigation for the SunRail Phase 1 segment, beginning at the proposed Debary Station and ending at the Sand Lake Road Station, and our geotechnical results and recommendations regarding the Phase 1 segment are included under separate cover. The Phase 2 South segment will begin at the proposed Sand Lake Road Station and end at the Poinciana Station, a distance of about 22 miles. There are four stations proposed along the SunRail Phase 2 South alignment: Meadow Woods, Osceola Parkway, Kissimmee and Poinciana. Additionally, there is a Vehicle Storage and Light Maintenance Facility (VSLMF) located to the east of the proposed Poinciana Station. This report documents the geotechnical investigation for the proposed Poinciana VSLMF. This report documents the geotechnical investigation for the proposed Poinciana VSLMF. Specifically, this report provides geotechnical engineering recommendations to guide design of the proposed track, office building and paved parking and drive areas within the limits of the proposed Poinciana VSLMF. The Poinciana VSLMF is located in Section 2, Township 26 South, Range 28 East in Poinciana, Osceola County, Florida. More specifically, the site is located between the existing CSX alignment and Old Tampa Highway between South Poinciana Boulevard and Dolores Drive. The VSLMF occupies an approximately 2,800 LF portion of the SunRail Phase 2 South alignment between stations and The Poinciana VSLMF site includes the right-of-way between the existing CSX alignment and Old Tampa Highway, which is undeveloped with heavy vegetation. According to the USGS Kissimmee, Florida Quadrangle map (Figure 1), the existing ground surface elevation across the subject site grades from approximately +71 to +65 feet NAVD east to west. GEC Project No. 2135G % Report of Geotechnical Engineering Investigation SunRail Phase 2 South Poinciana VSLMF

7 project plans include two track siding alignments for vehicle storage and maintenance, paved parking and drive areas and a single-story office building Based on our review of the VSLMF plans provided by AECOM, the project plans include the construction of two track siding alignments for vehicle storage and maintenance, paved parking and drive areas and a singlestory office building. In addition, we understand a retaining wall is proposed on the south side of the proposed office building; however, geotechnical recommendations regarding design of the proposed retaining wall are included under separate cover in the 100% Report of Geotechnical Engineering Investigation for the SunRail Phase 2 South mainline. A plan view of the Poinciana VSLMF layout is depicted on Figures 2A through 2D in the Appendix. 2.0 NRCS SOIL SURVEY AND POTENTIOMETRIC SURFACE MAPS REVIEW The Natural Resources Conservation Service (NRCS) (formerly SCS) Soil Survey of Osceola County, Florida was reviewed to obtain near-surface soil and groundwater information within the vicinity of the subject site. An excerpt from the NRCS Soil Survey Map of Osceola County is shown on Figure 1 in the Appendix. According to the NRCS, the following soils are present within the project limits: Table 1 NRCS Soil Survey Summary Soil Unit No. Soil Name 22 Myakka fine sand 24 Narcoossee fine sand 38 Riviera fine sand 39 Riviera fine sand, depressional Depth (in) Description Fine sand, sand Fine sand, loamy fine sand Fine sand, sand Fine sand, loamy fine sand Fine sand Fine sand Fine sand, sand Fine sand, sand Fine sand, sand Sandy clay loam, sandy loam Sandy clay loam, sandy loam Fine sand, loamy sand Fine sand, sand Sandy clay loam, sandy loam Sandy clay loam, sandy loam Fine sand, loamy sand USCS Classification Symbol SP, SP-SM SP-SM, SM SP, SP-SM SP-SM, SM SP-SM SP, SP-SM SP-SM SP, SP-SM SP, SP-SM SM, SC-CM, SC SC-SM, SC SP, SP-SM SP, SP-SM SM, SC-SM, SC SC-SM, SC SP, SP-SM AASHTO Classification Symbol A-3 A-3, A-2-4 A-3 A-3, A-2-4 A-3 A-3 A-3, A-2-4 A-3 A-3, A-2-4 A-2-4 A-2-4, A-2-6 A-3, A-2-4 A-3, A-2-4 A-2-4 A-2-4, A-2-6 A-3, A-2-4 Depth to Seasonal High Groundwater (feet) GEC Project No. 2135G % Report of Geotechnical Engineering Investigation SunRail Phase 2 South Poinciana VSLMF

8 Soil Unit No. Soil Name 45 Wabasso fine sand Depth (in) Description Fine sand Fine sand, loamy fine sand Sandy loam, sandy clay loam Sandy loam, sandy clay loam Sandy loam, sandy clay loam Sandy loam, sandy clay loam, loamy fine sand USCS Classification Symbol SP-SM, SM SM SC-SM, SC SM, SC-SM, SC SC-SM, SC SP, SP-SM AASHTO Classification Symbol A-3, A-2-4 A-2-4 A-2-4, A-2-6 A-2-4 A-2-4, A-2-6 A-3, A-2-4 Depth to Seasonal High Groundwater (feet) Information contained in the NRCS Soil Survey is very general and may be outdated. It may not, therefore, be reflective of actual soil and groundwater conditions, particularly if recent development in the site vicinity has modified soil conditions or surface/subsurface drainage. The information obtained from the soil borings provides a better characterization of actual site conditions. the potentiometric surface of the Floridan aquifer is estimated to be approximately +62 ft NGVD. Based on our review of the USGS map entitled Potentiometric Surface of the Upper Floridan Aquifer in the St. Johns River Water Management District and Vicinity, Florida, September 2008, the potentiometric surface of the Floridan aquifer in the vicinity of the subject site is estimated to be approximately +62 ft NGVD. Since ground surface elevations are higher than the potentiometric level at this location, artesian conditions are not anticipated. Artesian conditions were not encountered in our borings. 3.0 SUBSURFACE EXPLORATION during the 90% design phase the proposed VSLMF layout was modified and some previously performed borings are no longer located within the revised site footprint. In addition to consulting the sources of information previously discussed for regional and site-specific soils data, GEC conducted a subsurface exploration to evaluate soil and groundwater conditions at the proposed VSLMF. The subsurface exploration was performed in February 2013 utilizing preliminary project plans. However, during the 90% design phase the proposed VSLMF layout was modified and some previously performed borings are no longer located within the revised site footprint. GEC performed additional borings during the 100% design phase to address changes to the proposed site layout. The following Table 2 summarizes the subsurface exploration performed for each project element: GEC Project No. 2135G % Report of Geotechnical Engineering Investigation SunRail Phase 2 South Poinciana VSLMF

9 Table 2 Summary of Subsurface Exploration Program Project Element Boring No. *Boring Type Boring Depth (ft) Office Building VB-5 SPT 15 Paved Access Drives & Parking Areas VAB-1, -2, -4, -6, & -8 AB-146 AB HAB VAB-1, -3, -5, -7, -8, -9, -10, -11, -12, & -15 through -24 AB 10 VSLMF Tracks AB-133, -259, -134, -260, -136, -137, -261, -139, -140, -262, -142, -143, -145, & -263 HAB VB-1, VB-2 & VB-3 SPT 20 ** VAB-13 & VAB-14 AB 10 VB-4 SPT 15 * HAB Hand Auger Boring, AB Machine Auger Boring, SPT Standard Penetration Test Boring ** Due to changes in the proposed site layout these borings are no longer located within the footprint of proposed project elements for the Poinciana VSLMF. The approximate locations of the borings performed for this study are shown on Figures 2A through 2D in the Appendix. Boring locations were not established by survey, but rather by using a site plan provided by AECOM and a handheld, sub-meter accuracy, Global Positioning System (GPS) unit (Trimble GeoXH Series). Although the boring locations are given only approximately, the methods used to locate the borings are, in GEC s opinion, sufficient to meet the intent of our study. 3.1 SPT Borings SPT borings were drilled in general accordance with ASTM Procedure D The boreholes were advanced by the rotary wash method with bentonite-based mud used as the circulating fluid and to stabilize the borehole. GEC s field crew obtained SPT samples continuously in the borings to a depth of 10 feet and at 5-foot depth intervals thereafter. A GEC engineering technician monitored the drilling operation, and collected, examined and visually classified each sample. He then packaged representative portions of each sample for transport to our laboratory for further examination and laboratory testing. GEC Project No. 2135G % Report of Geotechnical Engineering Investigation SunRail Phase 2 South Poinciana VSLMF

10 3.2 Machine Auger Borings Machine auger borings were performed in accordance with ASTM Procedure D Machine auger borings were made by hydraulically turning a 4-inch wide continuous flight, solid-stem, auger into the ground in 5-foot increments until the desired boring termination depth was achieved. The auger flights were retrieved in 5-foot increments and examined by our technician prior to collection of representative soil samples. The samples were placed in sealed jars and transported to GEC s laboratory for further examination and limited laboratory testing. 3.3 Hand Auger Borings Our engineering technician performed standard barrel hand auger borings, ASTM D-4700, by manually turning a 3-inch diameter, 6-inch long sampler into the soil until it was full. He then retrieved the sampler and visually examined and classified the soil. This procedure was repeated until the desired termination depth was achieved. Our technician collected representative samples for further visual examination and classification in our laboratory. 3.4 Groundwater Measurement A GEC engineering technician measured the depth to groundwater in the boreholes at the time of drilling and again after approximately 24 hours. Once the 24-hour groundwater measurements were recorded, the boreholes were then backfilled with soil cuttings to prevailing ground surface. 4.0 LABORATORY TESTING Selected soil samples retrieved from the borings were tested in accordance with Florida Standard Testing Methods (FM). Florida Standard Testing Methods are adaptations of recognized standard methods, e.g., ASTM and AASHTO, which have been modified to accommodate Florida s geological conditions. The GEC laboratory has been reviewed by the Construction Materials Engineering Council, Inc. (CMEC) to verify compliance with FM. Our laboratory testing program is summarized in Table 3: Table 3 Summary of Laboratory Testing Program Type of Test Number of Tests Auger Borings SPT Borings Percent Fines (FM 1-T88) 0 4 Grain Size Analysis (FM 1-T88) 19 0 GEC Project No. 2135G % Report of Geotechnical Engineering Investigation SunRail Phase 2 South Poinciana VSLMF

11 Type of Test Number of Tests Auger Borings SPT Borings Atterberg Limits (FM 1-T89/90) 7 1 Natural Moisture Content (FM 1-T265) 11 1 Organic Content (FM 1-T267) 4 0 The results of the auger boring laboratory testing are summarized on the Soil Survey sheet (Figure 3), the Summary of Laboratory Test Results Table (Table 6) in the Appendix. In addition, the results of the SPT boring laboratory testing are shown adjacent to the soil profiles on Figure 6 in the Appendix. 5.0 DESCRIPTION OF SUBSURFACE CONDITIONS Detailed records of subsurface conditions encountered at our auger and SPT boring locations are presented on Figures 4 through 6 in the Appendix. The soils encountered in the SPT borings were classified using the Unified Soil Classification System (USCS) symbol (e.g., SP-SM). The soils encountered in the auger borings were classified using the American Association of State Highway and Transportation Officials (AASHTO) Soil Classification System symbol (e.g., A-3). Both SPT and auger borings were also classified using the ASTM soil descriptions (e.g., sand with silt). We based our soil classifications and descriptions on visual examination and the limited laboratory soil classification testing shown on the Boring Results sheets in the Appendix. The boring logs indicate subsurface conditions only at the specific boring locations at the time of our field exploration. Subsurface conditions, including groundwater levels, at other locations of the subject site may differ from conditions we encountered at the boring locations. Moreover, conditions at the boring locations can change over time. Groundwater levels fluctuate seasonally, and soil conditions can be altered by earthmoving operations. The depths and thicknesses of the subsurface strata indicated on the boring logs were interpolated between samples obtained at different depths in the borings. The actual transition between soil layers may be different than indicated. These stratification lines were used for our analytical purposes. Earthwork quantity estimates based on the results of the borings will vary from the actual quantities measured during construction. 5.1 Pavement and Track Auger Boring Results In general, the auger borings performed for the paved parking and drive areas and track siding alignments encountered fine sand with varying silt content (A-3, A-2-4) (Strata Nos. 1 and 2) to the GEC Project No. 2135G % Report of Geotechnical Engineering Investigation SunRail Phase 2 South Poinciana VSLMF

12 maximum boring termination depth of 10 feet below existing ground surface. However, boring AB- 259 encountered a 0.5-foot thick, buried layer of organic soil (A-8) (Stratum No. 3) at a depth of 1.5 feet. In addition, a 0.5-foot thick layer of clayey fine sand (A-2-6) (Stratum No. 4) was encountered at boring locations AB-260 at a depth of 4.5 feet. Surficial layers of ballast to ballast with sand (Stratum No. 5) were encountered at boring locations performed in close proximity to the existing rail embankment. The soil descriptions and stratum numbers used for the auger borings and the stratum utilization based on FDOT Standard Index 505 are summarized in the following table. Table 4 Summary of Soil Stratigraphy Stratum No. Soil Description AASHTO Soil Classification Symbol Embankment Fill Material Utilization (FDOT Index 505) 1 Light gray to brown to dark brown fine sand to fine sand with silt, occasional trace organic material, roots, and trace to A-3 Select (S) some ballast rock 2 Light brown to dark brown to orange fine sand with silt to silty fine sand, occasional trace organic material, roots, clay, A-2-4 Select (S) and trace to some ballast rock 3 Dark brown mucky fine sand A-8 Muck (M) 4 Light brown clayey fine sand A-2-6 Plastic (P) 5 Ballast rock to ballast rock with sand - - Please refer to Figures 4 through 5 in the Appendix for the specific subsurface profiles at the individual boring locations. 5.2 Track SPT Boring Results In general, the SPT borings performed along the track alignments encountered loose fine sand with silt to silty fine sand (SP-SM, SM) to a depth of 4 feet underlain by medium dense silty fine sand (SM) with trace clay to the maximum boring termination depth of 20 feet below existing ground surface. Please refer to Figure 6 in the Appendix for the specific subsurface profile at the individual boring locations. GEC Project No. 2135G % Report of Geotechnical Engineering Investigation SunRail Phase 2 South Poinciana VSLMF

13 5.3 VSLMF Building SPT Boring Results In general, the SPT boring VB-5 performed within the proposed footprint of the VSLMF building encountered loose to medium dense fine sand with silt to silty fine sand (SP-SM, SM) to the boring termination depth of 15 feet below existing ground surface. However, from a depth of 2 to 4 feet a layer for very loose silty fine sand was encountered at the proposed VSLMF building location. Please refer to Figure 6 in the Appendix for the specific subsurface profile at the individual boring locations. 5.4 Groundwater Levels Groundwater levels were typically encountered at depths ranging from 2.8 to 7.3 feet Groundwater levels were measured at least 24 hours after completion of the borings. Groundwater levels were typically encountered at depths ranging from 1.3 to 7.3 feet below the existing ground surface. However, at boring location AB-134, groundwater was encountered at a depth of 0.4 feet below the existing ground surface. Groundwater levels can vary seasonally and with changes in subsurface conditions between boring locations. Alterations in surface and/or subsurface drainage brought about by site development can also affect groundwater levels. Therefore, groundwater depths measured at different times or at different locations on the site can be expected to vary from those measured by GEC during this investigation. For the purposes of this report, estimated seasonal high groundwater levels are defined as groundwater levels that are anticipated at the end of the wet season of a normal rainfall year under current site conditions. We define a normal rainfall year as a year in which rainfall quantity and distribution were at or near historical rainfall averages. temporary, perched groundwater levels may occur after large rainfall events above the shallow silty and clayey sand layers encountered at the boring locations. GEC estimates that seasonal high groundwater levels will typically range from 0 to 3 feet below the existing ground surface. However, at boring locations AB-134, VAB-3, VAB-5 and VAB-15 the estimated seasonal high groundwater level is estimated to be above the existing ground surface, indicated by AGS on the boring profiles. In addition, temporary, perched groundwater levels may occur after large rainfall events above the shallow silty and clayey sand layers GEC Project No. 2135G % Report of Geotechnical Engineering Investigation SunRail Phase 2 South Poinciana VSLMF

14 encountered at the boring locations. The encountered and estimated seasonal high groundwater levels at the boring locations are presented on the Boring Results sheets (Figures 4 through 6) in the Appendix. 6.0 ANALYSIS AND DESIGN RECOMMENDATIONS The analyses and recommendations contained in this report are based in part on the data obtained from a limited number of soil samples and groundwater measurements obtained from widelyspaced borings. The sampling methods used indicate subsurface conditions only at the specific boring locations where samples were obtained, only at the time they were obtained, and only to the depths penetrated. Borings cannot be relied upon to accurately reflect the variations that usually exist between boring locations and these variations may not become evident until construction. If variations from the subsurface conditions described in this report do become evident during construction or if the project characteristics described in this report change, GEC should be retained to reevaluate this report's conclusions and recommendations in light of such changes. 6.1 Site Preparation Stratum 3 (Muck) should be completely removed in any structure or pavement locations unless shown as to remain in the plans. The results of our geotechnical investigation indicate that the majority of the near-surface soils encountered at the site are generally appropriate for structure and pavement construction. Standard site preparation procedures including topsoil stripping and proofrolling should be adequate in these areas. However, organic soils (Stratum 3) will need to be removed prior to construction. Stratum 3 (Muck) should be completely removed in any structure or pavement locations and backfilled with acceptable, compacted material unless shown as to remain in the plans. The buried organic material (Stratum 3) encountered at boring locations AB- 259 may remain in place, as depicted on the project cross-sections, based on the relatively low organic content and depth of the encountered material. The soils encountered on this project should be utilized as follows: GEC Project No. 2135G % Report of Geotechnical Engineering Investigation SunRail Phase 2 South Poinciana VSLMF

15 Table 5 Soil Utilization Stratum No. AASHTO Classification Embankment Soil Utilization 1 A-3 Select (S) 2 A-2-4 Select (S) 3 A-8 Muck (M) 4 A-2-6 Plastic (P) 5 * - * Stratum 5 is ballast rock to ballast rock with sand The soils utilized in construction should be selected in accordance with Index 505 of the FDOT Design Standards. The encountered soils identified as fine sand with variable silt content (Strata 1 and 2) should be considered Select (S) in accordance with FDOT Index 505. However, the silty fine sands (A-2-4/Stratum 2) may retain excess moisture and may be difficult to dry and compact. Therefore, the contractor should be prepared to manipulate the moisture content of unstable subgrade soils as necessary to achieve stability and compaction requirements. Backfill soils should consist of relatively clean sands, with no more than 12 percent (by weight) finer than the No. 200 sieve Backfill soils should consist of relatively clean sands, with no more than 12 percent (by weight) finer than the No. 200 sieve (A-3, A-2-4). Any plastic materials (Stratum 4) encountered on the project site are not suitable for use as fill and should be removed in accordance with Index 500 of the FDOT Design Standards. All backfill should be placed and compacted in accordance with the FDOT Standard Specifications for Road and Bridge Construction. In-place density tests should be performed on fill soils to verify the specified degree of compaction. The minimum test frequency should be in accordance with the FDOT Materials, Sampling, Testing and Reporting Guide. 6.2 Track Embankment The results of our geotechnical investigation indicate that the majority of the near-surface soils along the track siding alignments are Select (S) sands that are suitable for track construction. All fill soils placed for rail embankment construction should be selected in accordance with Index 505 of the FDOT Design Standards. The soils encountered in our borings classified as fine sand with silt (A-3) (Stratum 1) and silty fine sand (A-2-4) (Stratum 2) should be treated as Select (S) material. The A-2-4 material may retain excess moisture and may be difficult to dry and compact. GEC Project No. 2135G % Report of Geotechnical Engineering Investigation SunRail Phase 2 South Poinciana VSLMF

16 Therefore, the contractor should be prepared to manipulate the moisture content of unstable subsoil as necessary to achieve stability and compaction requirements. Any plastic materials (Stratum 4) encountered along the track alignments should be removed in accordance with the project plans and Index 500 of the FDOT Design Standards. organic soils should be excavated as depicted on the project cross-sections Any organic soils (Stratum 3) encountered along the track alignments should not be used in embankment construction. These organic soils should be excavated in accordance with Index 500 of the FDOT Design Standards as depicted on the project cross-sections unless shown as to remain in the plans. Embankment fill should be placed and compacted in accordance with the FDOT Standard Specifications for Road and Bridge Construction. In-place density tests should be performed on fill soils to verify the specified degree of compaction. The minimum test frequency should be in accordance with the FDOT Materials, Sampling, Testing and Reporting Guide. Ballast and subballast should be placed and compacted in accordance with AREMA guidelines. Groundwater levels are relatively shallow along the majority of the track alignments Groundwater levels are relatively shallow along the majority of the track alignments and providing adequate separation between the rail sub-ballast and the seasonal high groundwater level will be an important criterion in track design. 6.3 Pavements Flexible pavements can incorporate limerock base material if at least 2 feet of vertical separation is provided between the bottom of base and the seasonal high groundwater level. Our study results indicate that the site is suitable for support of conventional flexible pavement sections assuming that organic soils are removed as recommended in this report. Flexible pavements can incorporate limerock base material if at least 2 feet of vertical separation is provided between the bottom of base and the seasonal high groundwater level. An asphalt base material should be used if this vertical clearance cannot be provided. Furthermore, pavement underdrains will be needed if seasonal high groundwater levels are anticipated within 1 foot of the bottom of the pavement base. These conclusions are contingent upon preparation of proposed pavement areas in accordance with FDOT Standard Specifications. GEC Project No. 2135G % Report of Geotechnical Engineering Investigation SunRail Phase 2 South Poinciana VSLMF

17 The following recommended pavement section is typical of similar projects in this area and is not based on any traffic loading information or formal pavement design, since such information is not available. All pavement design should be conducted in accordance with the FDOT Flexible Pavement Manual and all pavement construction should be conducted with FDOT Standard Specifications. For light duty usage, such as automobile parking stalls and driveways, we recommend the following minimum pavement section. 1.5 inches Structural Asphalt Surface Course. 6 inches of limerock base course. 12 inches of stabilized subgrade (LBR=40). For heavy duty usage, such as driveways, delivery and dumpster access routes and perimeter roads, we recommend the following minimum pavement section: 2 inches Structural Asphalt Surface Course. 8 inches of limerock base course. 12 inches of stabilized subgrade (LBR=40). If traffic loading information becomes available, we should review it to confirm the suitability of these pavement sections in accordance with the FDOT Flexible Pavement Manual. 6.4 Foundations On the basis of the data obtained for this study, in our opinion the site can be made suitable for support of the proposed station platform on a system of conventional shallow isolated spread footings and/or continuous strip footings. This conclusion is contingent on the design engineer s and contractor s adherence to the following recommendations: Use a maximum net soil bearing pressure of 2,000 pounds per square foot in footing design. Use minimum footing dimensions of 24 inches for isolated spread footings and 18 inches for strip footings even though the maximum net soil bearing pressure may not be fully developed in all cases. GEC Project No. 2135G % Report of Geotechnical Engineering Investigation SunRail Phase 2 South Poinciana VSLMF

18 Design foundations so that all exterior footings bear at least 18 inches below finished exterior grades. Support floor slabs constructed on-grade on a compacted sand base. Prepare site and compact foundation subsoils in accordance with FDOT Standard Specifications. Our evaluation of site soils indicates that shallow foundations designed and constructed in accordance with the above recommendations, assuming footing loads no heavier than those typical for a one-story structure, will experience total settlements of less than about 1 inch and differential settlements between footings less than about 0.5 inches. 6.5 Temporary Excavations The owner and the contractor should be familiar with local, state and federal safety regulations, including current Occupational Safety and Health Administration (OSHA) excavation and trench safety standards. Construction site safety is the responsibility of the contractor. The contractor should also be responsible for the means, methods, techniques, sequences, and operations of the construction. The contractor should be aware that slope height, slope inclination, and excavation depths (including utility trench excavations) should not exceed those specified in local, state, or federal safety regulations; e.g., OSHA Health and Safety Standards for Excavations, 29 CFR Part OSHA regulations are strictly enforced and, if not followed, the owner, contractor, earthwork subcontractor or utility subcontractor could be liable for substantial penalties. The soil encountered in the borings performed by GEC at this site is primarily sand with varying amounts of silt. We anticipate that OSHA will classify these materials as Type C. OSHA recommends a maximum temporary slope inclination of 1.5 horizontal to 1 vertical for this soil type. Soils encountered in the construction excavations may vary significantly across the site. Our soil classifications are based on the materials encountered in widely-spaced borings. The contractor should verify that similar conditions exist throughout the proposed excavation area. If different subsurface conditions are encountered at the time of construction, GEC should be contacted immediately to evaluate the conditions encountered. GEC Project No. 2135G % Report of Geotechnical Engineering Investigation SunRail Phase 2 South Poinciana VSLMF

19 The contractor or the specialty subcontractor should be responsible for the design of the temporary shoring in accordance with applicable regulatory requirements. Since excavations will be required in the vicinity of existing facilities, the contractor should be required to provide temporary support of pavements and structures adjacent to excavations. If any excavation, including a utility trench, is extended to a depth of more than 20 feet, OSHA requires that the side slopes of such excavation be designed by a Professional Engineer registered in the State of Florida. As an alternative to temporary slopes, vertical excavations can be temporarily shored. The contractor or the specialty subcontractor should be responsible for the design of the temporary shoring in accordance with applicable regulatory requirements. Since excavations will be required in the vicinity of existing facilities, the contractor should be required to provide temporary support of pavements and structures adjacent to excavations. A facility condition survey should be performed prior to construction and movements or vibrations should be monitored in nearby structures during construction activities. Prior to performing the work, the contractor should provide a plan to the Engineer of Record for temporary support of existing facilities and for condition monitoring during construction. 6.6 Temporary Dewatering Depending on groundwater levels at the time of construction and final design grades, temporary dewatering may be required to facilitate stable excavations and placement and compaction of fill. The contractor should be required to provide a dewatering system which maintains groundwater levels at least 2 feet below proofrolled and compaction surfaces, including the bottom of excavations. A system of ditches and sumps may be sufficient in some instances to achieve adequate dewatering, but the contractor should be prepared to install wellpoint dewatering systems as necessary. the contractor must provide positive site drainage during site preparation and fill placement. Additionally, the contractor must provide positive site drainage during site preparation and fill placement. Surface runoff should not be allowed to accumulate. Temporary rim ditches may be required to facilitate site preparation. GEC Project No. 2135G % Report of Geotechnical Engineering Investigation SunRail Phase 2 South Poinciana VSLMF

20 7.0 USE OF THIS REPORT GEC has prepared this report for the exclusive use of our client, AECOM, and the FDOT, and for specific application to our client s project. GEC will not be held responsible for any other party s interpretation or use of this report s subsurface data without our written authorization. The sole purpose of the borings performed by GEC at this site was to obtain indications of subsurface conditions as part of a geotechnical exploration program. GEC submitted our Contamination Screening Evaluation Report and Level II Contamination Assessment Report under separate cover. GEC has strived to provide the services described in this report in a manner consistent with that level of care and skill ordinarily exercised by members of our profession currently practicing in Central Florida. No other representation is made or implied in this document. GEC should be retained to review the new plans to assess the applicability of this report in light of proposed changes. The conclusions or recommendations of this report should be disregarded if the nature, design, or location of the facilities is changed. If such changes are contemplated, GEC should be retained to review the new plans to assess the applicability of this report in light of proposed changes. GEC Project No. 2135G % Report of Geotechnical Engineering Investigation SunRail Phase 2 South Poinciana VSLMF

21 APPENDIX

22 USGS QUADRANGLE AND NRCS SOIL SURVEY MAPS

23

24 BORING LOCATION PLAN

25

26

27

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29 SOIL SURVEY

30

31 TRACK AUGER BORING RESULTS

32

33

34 TRACK SPT BORING RESULTS

35

36 SUMMARY OF LABORATORY TEST RESULTS

37 Table 6 Summary of Laboratory Test Results SunRail Phase 2 South - Poinciana VSLMF FPID No GEC Project No. 2135G6 Page 1 of 1 Sample Percent Passing by Weight Moisture Atterberg Limits Organic Stratum Boring Depth #10 #40 #60 #100 #200 Content Liquid Plasticity Content AASHTO Number No. (feet) Sieve Sieve Sieve Sieve Sieve (%) Limit Index (%) Class. 1 AB A-3 1 VAB A-3 1 VAB A-3 1 VAB A-3 2 AB NP NP --- A AB NP NP --- A AB A VAB NP NP --- A VAB NP NP --- A VAB NP NP --- A VAB NP NP --- A VAB A VAB NP NP --- A VAB A VAB A VAB A VAB A VAB A AB A-8