GEOTECHNICAL ENGINEERING REPORT

Transcription

1 GEOTECHNICAL ENGINEERING REPORT Crews Park at Peace River 130 Park Drive Wauchula, FL PREPARED FOR: Kimley-Horn and Associates 116 South Kentucky Avenue Lakeland, FL NOVA Project Number: June 23, 2017

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3 EXECUTIVE SUMMARY The following information is provided as a brief summary of details contained in the attached report. The report should be read in its entirety prior to the implementation into design and construction. 1. The site is located on the existing Crews Park and Peace River Park in Wauchula, Florida. A new recreation area is proposed to be constructed at the Crews Park including picnic pavilions, modified boat ramp, kayak storage pavilion, and paved surface parking and drive areas. Additionally, the proposed Peace River Park development will include picnic pavilions, a refurbished bridge, trailhead kiosk, and paved surface parking and drive areas. 2. Five (5) soil borings were drilled at the site, including one (1) within the proposed pavilion footprint, one (1) within the proposed storm water pond, and three (3) borings within the proposed paved parking areas. The soil borings encountered predominantly sandy except in borings B-2, B-3, and B-4 drilled in Crews Park. In B-2, B-3 and B-4, organic sand/silt with wood and other debris were encountered, extending to depths of about 7, 3, and 3 feet (bgs), respectively. Depths to groundwater table were measured to be between 2 and 8 feet (bgs) in Crews Park and about 10 feet (bgs) in Peace River Park. The depths to seasonal high water table were estimated to be ranging from 0 to 6 feet (bgs) in Crews Park and about 8 feet (bgs) in Peace River Park. 3. Before construction the site should be cleared. This will primarily include stripping of any topsoil, vegetation, organics, trash, and other unsuitable materials. Unsuitable materials detected in borings B-2 through B-4 should be excavated and removed from the site. To help detect near surface soft unsuitable/unstable materials, the site should then be proof-rolled using a heavy roller. Extreme caution should be used when operating a vibratory roller within 75 feet of any existing structure. 4. Structural fill for the building area should consist of clean sands (SP, SP-SM) and should be compacted to at least 95 percent of the Modified Proctor maximum dry density. In general, based upon the boring results, the near surface sands such as those encountered in the borings within the top 2 feet of the subsurface can be used as a structural fill, provided that the material is free of debris, clay, rock, roots and organics. 5. After site preparations as recommended, including an intensive compaction program, the proposed building structures can be supported using conventional spread footings designed for a net allowable bearing pressure of 2,500 pounds per square feet. 6. We recommend using a flexible pavement system for the construction of the paved parking areas and access roadways. For standard duty traffic, a flexible pavement section consisting of 1.5 inches of asphaltic concrete underlain by 6 inches of crushed concrete/limerock base over 12 inches of stabilized subgrade is recommended. For heavy-duty traffic, a flexible pavement section consisting of 2.0 inches of asphaltic concrete underlain by 8 inches of crushed concrete/limerock base over 12 inches of stabilized subgrade is recommended. ii

4 TABLE OF CONTENTS LETTER OF TRANSMITTAL i EXECUTIVE SUMMARY ii 1.0 PROJECT OVERVIEW INTRODUCTION SITE AND PROJECT DESCRIPTION PURPOSE AND SCOPE OF SERVICES EXPLORATION PROCEDURES SUBSURFACE EXPLORATION OPEN HOLE PERCOLATION TEST LABORATORY TESTING SUBSURFACE CONDITIONS CURRENT SITE CONDITIONS COUNTY SOIL SURVEY SUBSURFACE CONDITIONS GROUNDWATER OBSERVATIONS HYDRAULIC CONDUCTIVITY GENERALIZED SOIL PROFILE CONCLUSIONS AND RECOMMENDATIONS GENERAL FOUNDATIONS FLOOR SLAB DESIGN EARTHWORK OPERATIONS BORROW AND ON-SITE SOIL SUITABILITY PAVEMENT CONSIDERATIONS APPENDIX Appendix A Figures Appendix B Test Boring Records Appendix C Percolation Test Data Appendix D Laboratory Test Data Appendix E Qualifications of Recommendations iii

5 1.1 INTRODUCTION 1.0 PROJECT OVERVIEW In accordance with your request and authorization, NOVA has completed a subsurface exploration and geotechnical engineering evaluation for the above referenced project. We explored the general subsurface conditions in order to evaluate their suitability for the support of the proposed construction, to obtain a measure of pertinent engineering properties of subsurface materials and to provide recommendations for site preparation and foundation design. Our work included five (5) soil borings, one (1) percolation test, laboratory testing, and engineering analyses. This report describes our exploration and tests, reports our findings, and summarizes our conclusions and recommendations. 1.2 SITE AND PROJECT DESCRIPTION Our understanding of the project is based on a review of the following documents: Overall Master Plan prepared by Kimley-Horn and dated February 24, The subject site is divided by State Road 64 with Crews Park to the north and Peace River Park to the south. Crews Park is bounded by SR 64 to the south, Peace River to the east, residential developments to the north, and Riverside Drive, Palmetto Street, and Park Drive to the west. Peace River Park is bounded by SR 64 to the north, Griffin Road to the south, Peace River to the east, and residential developments to the west. According to the information provided to us, a new recreation area will be constructed in Crews Park, including picnic pavilions, modified boat ramp, kayak storage pavilion, and paved surface parking and drive areas. A storm water pond is proposed to be constructed west of the Crews Park parking area. Additionally, the proposed Peace River Park development will include picnic pavilions, a refurbished bridge, trailhead kiosk, and paved surface parking and drive areas. It is our understanding that the proposed pavilion to be constructed on site will be the only building structure to be addressed in this study. No structural load data was provided to us for the proposed structure at the time of this report. 1.3 PURPOSE AND SCOPE OF SERVICES The purpose of this study was to obtain information on the general subsurface conditions at the proposed project site. The subsurface materials encountered were evaluated with respect to the available project characteristics. In this regard, engineering assessments for the following objectives were formulated: Page 1

6 General location and description of potentially deleterious materials encountered in the borings which may interfere with construction progress or structure performance, including existing fills or surficial/subsurface organics. Identification of the existing ground water levels and estimated normal seasonal high ground water fluctuations. Evaluation of the feasibility of using a conventional shallow foundation system for support of the proposed structure. Develop recommendation of foundation design parameters, including allowable load capacities. Recommend soil subgrade preparation operations, including stripping, grubbing, and compaction. Recommended engineering criteria for placement and compaction of approved structural fill materials. Evaluation of the suitability and availability of materials on-site that may be moved during site grading for use as structural fill in the building area, as pavement subgrade fill, and as general backfill. Presentation of construction recommendations, including expected ground water control measures, temporary slope stability recommendations, and unsuitable soil removal guidelines. The following specific tasks were performed in the geotechnical exploration: Reviewed readily available published geologic and topographic information. This information will be obtained from Quadrangle Maps published by the United States Geological Survey (USGS) and Soil Survey of Hardee County, Florida" published by the United States Department of Agriculture (USDA) Natural Resources Conservation Service (NRCS). Executed a program of subsurface exploration consisting of subsurface sampling and field testing. We performed five (5) soil test borings, including the following: o One (1) boring to 20 feet below existing ground surface (bgs) within/near the footprint of the proposed building; o One (1) boring to 20 feet (bgs) within the area of the proposed storm water pond; and o Three (3) borings to 10 feet (bgs) within the proposed paved parking areas and driveways. Page 2

7 Our Field Exploration Plan is attached in Appendix A. SPT s were performed and split-spoon soil samples were collected continuously in the first 10 feet of the test borings, and every five (5) feet thereafter. Visually classified and stratified representative soil samples in the laboratory using the Unified Soil Classification System (USCS). Conducted a limited laboratory-testing program. Identified soil conditions at each boring location and formed an opinion of the site soil stratigraphy. Groundwater level measurements in the borings were collected at the time drilling. Performed one (1) Open-Hole Percolation/Hydraulic Conductivity test east of the Peace River Park new parking lot. The results of the field exploration and laboratory tests were used in the engineering analysis and in the formulation of geotechnical recommendations. The results of the subsurface exploration, including the recommendations and the data upon which they are based, are presented in this formal written report prepared by a Professional Geotechnical Engineer. The scope of this exploration did not include an evaluation of potential deep soil problems, such as sinkholes. A sinkhole evaluation may be performed at your request and with authorization. In order to perform such an evaluation, it is expected that Ground Penetrating Radar (GPR) in conjunction with deep soil test borings drilled into limestone formation will be required. The scope of our services did not include any environmental assessment or investigation for the presence or absence of hazardous or toxic materials in the soil, ground water, or surface water within or beyond the site studied. Any statements in the report regarding odors, staining of soils, or other unusual conditions observed are strictly for the information of our client. Page 3

8 2.1 SUBSURFACE EXPLORATION 2.0 EXPLORATION PROCEDURES To explore subsurface conditions at the site, five (5) soil borings were performed at the site. The approximate locations of the borings are shown on Figure 1 Field Exploration Plan, presented in Appendix A. Our field exploration was conducted on June 12, The boring locations illustrated in the Appendix should be considered accurate only to the degree implied by the method used. If more precise locations are desired, we suggest that you contact a Registered Surveyor. It is important to note that ground surface elevations at the boring locations were neither furnished nor determined. The Standard Penetration Test (SPT) borings were performed using the guidelines of ASTM Designation D-1586, "Penetration Test and Split-Barrel Sampling of Soils". A mud rotary drilling process was used to advance the borings. At regular intervals, the drilling tools were removed and soil samples were obtained with a standard 1.4-inch I.D., 2.0- inch O.D., split-tube sampler. The sampler was first seated six inches and then driven an additional foot with blows of a 140-pound hammer falling 30 inches. The number of hammer blows required to drive the sampler the final foot is designated the "Penetration Resistance". The penetration resistance, when properly interpreted, is an index to the soil strength and density. Representative portions of the soil samples, obtained from the sampler, were placed in glass jars and transported to our laboratory for further evaluation and laboratory testing. 2.2 OPEN HOLE PERCOLATION TEST One (1) open-hole percolation (hydraulic conductivity) test was performed at the site. The percolation test was performed in general accordance with the Southwest Florida Water Management District (SWFWMD) Constant Head Open-Hole Test procedure. A 3-inch diameter hole was augered from the ground surface to approximately one foot below ground water table. An open-ended 2-inch diameter perforated PVC pipe was installed in the augered borehole. Water was added to the pipe through a metering system. The water level in the pipe was maintained at a constant level (at the ground surface level) until steady state flow is achieved. Three trial runs were performed for each percolation test. For each trial the water level was maintained at the ground surface for a period of 10 minutes, and water quantities added to the pipe/casing in every 1-minute period was recorded. 2.3 LABORATORY TESTING The recovered soil samples were transported to our Tampa soils laboratory from the Page 4

9 project site. Each soil sample was then examined by a Geotechnical Engineer using the Unified Soil Classification System using the guidelines of American Society of Testing and Materials (ASTM) Test Designations D-2487 and D Due to the structural characteristics of the proposed facility and the nature of the soils encountered, representative soil samples were selected for moisture, fines content, and organic content testing. The laboratory test results are presented in Appendix D of this report. It should be noted that all soil samples would be properly disposed of 30 days following the submittal of this NOVA subsurface exploration report unless you request otherwise Soil Classification Soil classifications provide a general guide to the engineering properties of various soil types and enable the engineer to apply past experience to current problems. In our explorations, samples obtained during drilling operations are observed in our laboratory and visually classified by an engineer. The soils are classified according to consistency (based on number of blows from standard penetration tests), color and texture. These classification descriptions are included on our "Test Boring Records". The classification system discussed above is primarily qualitative; laboratory testing is generally performed for detailed soil classification. Using the test results, the soils were classified using the Unified Soil Classification Systems. This classification system and the in-place physical soil properties provide an index for estimating the soil's behavior. The soil classification and physical properties obtained are presented in this report Moisture Content The moisture content is the ratio expressed as a percentage of the weight of water in a given mass of soil to the weight of the solid particles. This test was conducted in general accordance with ASTM D Particle Size Analysis The particle size analysis consists of passing a soil sample through a series of standard sieve openings. The percentage of soil, by weight, passing the individual sieves is then recorded and generally presented in a graphical format. The percentage of fines passing through the No. 200 sieve is generally considered to represent the amount of silt and clay of the tested soil sample. The particle size analysis test was conducted in general accordance with ASTM Designation D Page 5

10 2.3.4 Organic Content The organic content is the ratio, expressed as a percentage, of the mass of organic matter in a given mass of soil to the mass of the dry soil solids. Standard Reference: ASTM D 2974 Standard Test Methods for Moisture, Ash, and Organic Matter of Peat and Organic Soils. Page 6

11 3.1 CURRENT SITE CONDITIONS 3.0 SUBSURFACE CONDITIONS A NOVA geotechnical engineer conducted a site reconnaissance during the exploration. At the time of the exploration, approximately two-thirds of the Crews Park area was massgraded and prepared as a drainage pond. This area, which will be used as a storm water pond and a portion of the new paved surface parking, appears to be frequently flooded. Multiple pavilions over concrete slabs, a restroom facility, and gravel drive path were present with the remainder of the Crews Park site being grassed and vacant. The Peace River Park area is mostly undeveloped and grassed with a small limerock parking area. The Crews Park site estimated elevation ranges between El. 46 and El. 59 feet MSL while the Peace River site estimated elevation ranges between El. 55 and El. 63 feet MSL. Topographic survey information provided by a review of the 7.5-minute topographic map of the Wauchula Florida Quadrangle indicated that the overall site previously ranged between El. 50 to El. 55 feet MSL. 3.2 COUNTY SOIL SURVEY The Soil Survey of Hardee County, Florida, published by the United States Department of Agriculture (USDA) National Resources Conservation Service (NRCS), was reviewed for general near-surface soil information within the general vicinity of the subject project. This information indicates that the site is covered with three primary soil-mapping units. The soil map unit characteristics are tabulated below: SOIL SERIES DEPTH UNIFIED SOIL CLASSIFICATION Felda fine sand, 0 to 2 percent slopes (11) Wabasso fine sand, 0 to 2 percent slopes (29) Bradenton-Felda- Chobee association, frequently flooded (27) (INCH) HYDRO- LOGIC GROUP USDA SEASONAL HIGH GROUNDWATER TABLE DEPTH MONTHS (FEET) 0 80 Fine sand A/D 0 to 0.5 Jun - Sep 0 80 Fine sand A/D 0.5 to 1.5 Jun - Sep 0 80 Fine sand A/D 0 to 1.0 Jun - Sep Page 7

12 3.3 SUBSURFACE CONDITIONS Subsurface conditions within the project site were evaluated using five soil test borings drilled to 10 to 20 feet (bgs). The subsurface conditions encountered at the boring locations are described on the Test Boring Records in Appendix B of this report. These records represent our interpretation of the subsurface conditions based on the field logs and visual observations of samples by an engineer. The lines designating the interface between various strata on the Boring Records represent the approximate interface locations and elevation. The actual transition between strata may be gradual. Groundwater levels shown on the Boring Records represent the conditions only at the time of our exploration. It should be understood that soil and rock conditions may vary between boring locations. The five (5) borings drilled at the site penetrated a layer of topsoil with a thickness on the order of 3 inches. Underneath these surficial materials, the soil/rock materials encountered in the soil borings within the top 20 feet of the subsurface are briefly discussed below for different areas of the site Pavilion in Crews Park Boring B-1 was drilled in the footprint of the proposed pavilion in the Crews Park. The soil boring encountered a layer of dark brown silty fine sand with trace of roots to about 2 feet (bgs), a layer of dark brown to brown clayey sand to about 7 feet (bgs), a layer of medium dense fine sand to 10 feet (bgs), a layer of medium dense clayey sand to 14 feet (bgs), followed by limestone to the boring termination depth of 20 feet (bgs) Pond in Crews Park Boring B-2 was drilled in the footprint of the proposed storm water pond in Crews Park. The soil boring encountered a layer of dark brown silty fine sand with trace of roots to about 2 feet (bgs), a layer of organic silt or sand with wood and other debris to about 7 feet (bgs), followed by a layer of very loose sand to about 19 feet (bgs), which is underlain by a layer of limestone extending to the boring termination depth of 20 feet (bgs) Parking in Crews Park Borings B-3 and B-4 were drilled in proposed parking area in Crews Park. The soil borings encountered a layer of loose sand to about 2 feet, followed by a layer of organic silt with wood debris. A sample from boring B-4 was tested for organic and fines contents, Organic and fines contents were measured to be 33.5 and 19.8%, respectively. Underneath the organic layer, the soil borings encountered a layer of Page 8

13 loose to medium dense sand to 6 to 8 feet (bgs), which is underlain by a layer of clayey sand or sandy clay to the maximum boring termination depth of 10 feet (bgs), Parking in Peace River Park Boring B-5 was drilled in the proposed parking area in the Peace River Park. The soil boring encountered a layer of loose sand to about 2 feet (bgs), a layer of firm dark brown silty clay to about 3 feet (bgs), which is underlain by a layer of loose sand to about 4 feet, followed by a layer of medium dense sand to the boring termination depths of 10 feet (bgs). 3.4 GROUNDWATER OBSERVATIONS Depths to the groundwater table were measured at each soil test boring and open-hole percolation test location and recorded at the time of drilling. Measured groundwater table and estimated seasonal high water table depths and elevations for each are recorded along with an overall average for the site in the table below. Boring Location Estimated Ground Surface Elevation Fluctuations in groundwater level should be anticipated throughout the year due to a variety of factors, the most important of which are recharge from rainfall. As can be observed in the above table, depth to seasonal high water table in the proposed storm water pond in Crews Park is estimated to be at approximately 3 feet (bgs). The depths to seasonal high water table in the proposed parking area in Crews Park were estimated to be between 0 and 2 feet (bgs), averaging about 1 foot (bgs). The depths to seasonal high water table in the proposed parking area in Peace River Park were estimated to be between 7.5 and 8.0 feet (bgs). 3.5 HYDRAULIC CONDUCTIVITY GROUNDWATER OBSERVATIONS Depth to Groundwater Table Elevation of Groundwater Table Estimated Seasonal High Water Table Elevation of Seasonal High Water Table (FT-BGS) (FT-MSL) (FT-BGS) (FT-MSL) B B B B B P The open-hole percolation test measures average horizontal hydraulic conductivity of the Page 9

14 aquifer materials between the ground surface and the testing depths. The hydraulic conductivity was measured to be 2.1x10-5 cfs/ft 2 -ft of head. Detailed test results are presented in Appendix C. 3.6 GENERALIZED SOIL PROFILE To facilitate discussion, a generalized soil profile is presented in the following table for the subject site. The generalized soil profile represents the average conditions within the top 20 feet of the subsurface encountered in the soil test borings. GENERALIZED SOIL PROFILE SOIL MATERIAL USCS DEPTH TO TOP THICK. SPT N UNIT DESCRIPTION SURFACE VALUE (FT-BGS) (FT) (blow/ft) 1 Loose fine sand SP, SP-SM, SM 2 Organic silt/sand with wood debris OL Loose clayey fine sand SP-SC, SC Medium dense fine sand SP Very loose to medium dense fine SP, SP-SC, sand with phosphates SC 6 Soft to moderately hard limestone >50 Ground Surface Elevation (feet-navd88) = 53.2 Depth to Ground Water Table (ft-bgs) = 6.4 Depth to Seasonal High Water Table (ft-bgs) = 4.4 Page 10

15 4.1 GENERAL 4.0 CONCLUSIONS AND RECOMMENDATIONS Our understanding of the project is based on the project information provided to us. The development of the project site will include the construction of a new recreation area at Crews Park, including picnic pavilions, modified boat ramp, kayak storage pavilion, and paved surface parking and drive areas. A storm water pond is proposed to be constructed west of the Crews Park parking area. The proposed Peace River Park development will include picnic pavilions, a refurbished bridge, trailhead kiosk, and paved surface parking and drive areas. The following design recommendations have been developed on the basis of the previously described project characteristics and subsurface conditions encountered during this exploration. The test boring data was evaluated utilizing correlations between the measured standard penetration test resistances and the engineering performance characteristics of similar subsurface conditions. Subsurface conditions in unexplored locations or at other times may vary from those encountered at specific boring locations. If such variations are noted during construction, we request the opportunity to review the changes and amend our recommendations, if necessary If there is any change in these project criteria, it is considered essential that a review be made by NOVA to determine if any modifications to the recommendations will be required. After final design plans and specifications are available, a general review by NOVA is strongly recommended as a means to check that the evaluations made in preparation of this report are correct, and that earthwork and foundation recommendations are properly interpreted and implemented. 4.2 FOUNDATIONS After the recommended site and subgrade preparation and fill placement, including an intensive compaction program, we recommend a conventional shallow foundation be used to support the proposed pavilions. The shallow foundations should be designed using a maximum allowable soil bearing pressure of 2,500 pounds per square foot (psf). The aforementioned bearing pressure is based on the foundation bottoms being compacted to 95% of a Modified Proctor value to a minimum depth of one (1) foot below the foundation bearing surface. The foundations should bear on properly improved natural subgrade or on properly placed and compacted cohesionless (slightly silty sand) fill soils. Page 11

16 The exterior foundations should be embedded so that the bottom of the foundations are at least 16 inches below the adjacent compacted grades on all sides to allow for proper confinement; interior grade beam foundations may be located at nominal depths below the floor slab elevations. It is also recommended that any grade-beam foundations be a minimum of 36 inches wide to provide adequate load bearing area to develop overall bearing capacity and account for minor variations in the bearing materials. All footings should be constructed in a "dry" fashion, that is, it is recommended that the groundwater levels be maintained at least one (1) foot below the footing bottoms. It is important that the structural elements be centered on the footings such so that loads are transferred evenly, unless the footings are adequately proportioned for eccentric loads. Settlement of individual footings designed in accordance with the recommendations outlined above is expected to be less than one (1) inch with differential settlements per 30 feet of wall footing expected to be on the order of 0.5 inches or less. These settlement estimates are based on our engineering experience with these soils and are provided to guide the structural design. Total and differential settlements of these magnitudes are usually considered tolerable for the anticipated construction; the tolerance of the proposed structure to the predicted total and differential settlements should be confirmed by the Structural Engineer. 4.3 FLOOR SLAB DESIGN The slab on grade may be designed based on a subgrade modulus (K 1 ) of 125 pci for the analysis of concrete slab thickness, provided that 4-inch thick layer of compacted crushed stone is placed beneath the floor slab, which in turn is supported on structural fill compacted to density no less than 95% of Maximum Modified Proctor Dry Density. The design should include joint preparation in accordance with ACI recommended practices. The value (K 1 ) is for a unit footing dimension of 1 foot by 1 foot (for situations such as wheels of a forklift); for larger foundations, the k-value should be reduced in accordance with the following equation: K = K1 ( B+1 ) 2 2B Where B is the foundation width in feet. Page 12

17 It should be noted that for a large foundation width B for situations such as areal loading for warehouses, K approaches K 1 /4 or approximately 30 pci for this case. It is recommended that the floor slab bearing soils be covered by a lapped polyethylene sheeting of at least 6-mil thickness in order to reduce the potential for floor dampness which can affect the performance of glued tile and carpet, if any are used. This membrane should consist of a 6-mil single layer of non-corroding, non-deteriorating polyethylene sheeting material placed so as to minimize seams and to cover all of the soil below the building floor slab. This membrane should be cut in a cross shape to allow for pipes or other penetrations and the membrane should extend to within ½ inch of all such pipes or penetrations. All seams of the membrane should be lapped at least 12 inches. Punctures or tears in the membrane should be repaired with the same or comparable material and sealed in a waterproof manner. The performance of concrete floor slabs is also affected by the concrete mix that is used. A relatively high water-cement ratio of the concrete can cause aesthetic disruptions, such as unsightly slab curling and shrinkage cracking. Also, an additional waiting period may be required prior to installing moisture-sensitive floor covering because of the moisture loss from the concrete floor slab. In order to reduce slab curling it is suggested that the vapor barrier be covered with a 2-inch thick layer of clean sand or approved suitable granular material. 4.4 EARTHWORK OPERATIONS Subgrade Preparation Prior to construction, the location of any existing underground utility lines within the construction area should be established. Provision should then be made to relocate interfering utility lines from the construction area to appropriate locations. In this regard, it should be noted that if underground pipes are not properly removed or plugged, they may serve as conduits for subsurface erosion, which subsequently may result in excessive settlements. The site should be cleared before construction. This will primarily include stripping of existing vegetation, root systems, and topsoil. If encountered, trash and other unsuitable materials should also be removed from the construction area. It is recommended a minimum stripping depth of 6 inches. The stripping within the proposed construction area should be extended at least 5 feet, where possible, beyond the planned construction limits. Any roots with diameters greater than one (1) inches should be removed. Page 13

18 4.4.2 Excavation of Unsuitable Materials After site clearing, unsuitable materials should be removed from the site. Unsuitable materials in the form of organic soils with wood and other debris were encountered in borings B-2, B-3 and B-4, extending to depths of 7, 3, and 3 feet (bgs), respectively. Excavation should start at each of the three boring locations, extending laterally and vertically until unsuitable soils are completely removed in the area around each of the three boring locations. To help detect near surface soft unsuitable/unstable materials, the site should then be thoroughly proof-rolled using a heavy compactor such as a fully-loaded double axle dump truck, or a heavy (10-12 tons) roller. Any soft, yielding soils detected during the proof-rolling operations should be excavated and replaced with approved fill conforming to the specifications below. Sufficient passes should be made during the proof-rolling operations to produce minimum dry densities of 95 percent of the Modified Proctor (ASTM D-1557) maximum dry density value of the compacted subgrade soils to depths of one (1) foot below the compacted surface. The proof-rolled areas should receive no less than 8 overlapping passes, half of them in each of two perpendicular directions. If a vibratory roller is used, extreme caution should be used when operating the vibratory compactor near existing structures (within 75 feet) to avoid the transmission of vibration that could cause settlement damage, cracking or disturbance of occupants. The contractor shall be responsible for any damages to existing structures due to vibration Fill Placement All fill to be placed on site should consist of clean, granular, inorganic sandy soils with less than 12 percent passing the US No. 200 sieve. Structural fill materials should be placed in lifts not exceeding 12 inches in loose thickness and should be compacted to at least 95 percent of the maximum dry density as determined by the Modified Proctor Test Method (ASTM D-1557). Fill placed in non-structural areas (e.g. grassed areas) should be compacted to at least 90 percent of the maximum dry density according to ASTM D-1557, in order to avoid significant subsidence. The upper one foot of soils supporting slabs-on-grade and pavements should also be compacted to a minimum of 98 percent of the maximum dry density obtained in accordance with the ASTM Specification D-1557, Modified Proctor Method discussed above. Compliance tests should be performed at a rate of 1 test per 2,500 square feet per foot of improvement (depth) in the structural areas Page 14

19 and 1 test per 5,000 square feet in paved areas. If any problems are encountered during the earthwork operations, or if site conditions deviate from those encountered during our subsurface exploration, the Geotechnical Engineer should be notified immediately Groundwater Control Groundwater levels should be determined immediately prior to excavations and construction. Shallow groundwater should be kept at least one foot below the lowest working area to facilitate proper material placement and compaction. Depending upon groundwater levels at the time of construction, some form of dewatering may be required to achieve the required compaction and to prevent seepage from entering the bottom and/or sides of the excavations. Groundwater can normally be controlled in shallow excavations with a pump-and sump system or a system of well points. Soils exposed in the bases of all satisfactory foundation excavations should be protected against any detrimental change in conditions, such as physical disturbance or rainwater. Surface runoff water should be drained away from the excavations and not be allowed to pond. If possible, all footing concrete should be placed the same day that the excavations are made. If this is not possible, the footing excavations should be adequately protected in the interim. At the time of this subsurface exploration, groundwater table was measured to be at depths ranging from 2 to 8 feet (bgs) in Crews Park and about 10 feet (bgs) in the area explored in Peace River Park. It is our estimate that the seasonal high groundwater table in Crews Park is at depths ranging from 0 to 6 feet (bgs) and at about 8 feet (bgs) in the area explored in Peace River Park. It is likely that dewatering measures will be needed for the project during construction, depending on design elevation and the time of construction. However, we expect a pump-and-sump system to be sufficient for controlling groundwater at the site, if necessary Temporary Side-slopes All open-cut excavation areas should be properly dewatered, if required, for a period of at least 24 hours prior to the initiation of excavation operations. Following the proper dewatering operations, if required, side slopes for temporary excavations may stand near 1½ horizontal to one (1) vertical (1½H:1V) for short dry periods of time to a maximum excavation depth of six feet. Where restrictions do not permit slopes to be constructed as recommended above, the excavation should be shored and braced in accordance with current OSHA requirements. Furthermore, open-cut excavations up to Page 15

20 a maximum depth of ten (10) feet should be sloped to 2H: 1V or flatter slopes or be braced using an approved bracing plan. Excavated materials should not be stockpiled at the top of any slope within a horizontal distance equal to the excavation depth Foundation Excavation and Final Compaction It is considered essential that all foundation excavations be observed by a geotechnical engineer or an approved representative to ensure that footings are placed on suitable load bearing materials. If unsuitable materials are encountered in the footing excavations, the materials should be removed and the footings placed at lower elevations. This backfilling may be done with a very lean concrete or with a wellcompacted, suitable fill such as clean sand, gravel, or crushed FDOT No. 57 or FDOT No. 67 stones. Exposure to the environment may weaken the soils at the footing bearing level if the foundation excavations remain open for too long a time. Therefore, foundation concrete should be placed the same day that excavations are dug during the rainy season or if rain is anticipated. If the bearing soils are softened by surface water intrusion or exposure, the softened soils must be removed from the foundation excavation bottom immediately prior to placement of concrete. If the excavation must remain open overnight, or if rainfall becomes imminent while the bearing soils are exposed, we recommend that a 1- to 3-inch thick "mud-mat" of "lean" concrete be placed on the bearing soils before the placement of reinforcing steel. The bottom of the foundation excavations should be compacted to densify soils loosen during or after the excavation process and washed or sloughed into the excavation prior to the placement of forms. A heavy-duty vibratory rammer should be used for this final compaction, immediately prior to the placement of reinforcing steel, with previously described minimum dry density requirements to be maintained below the foundation level. After foundation forms are removed, backfill around foundations should be placed in lifts six inches or less in thickness, with each lift individually compacted with a plate tamper. The backfill should be compacted to a dry density of at least 95% of the modified Proctor (ASTM D-1557) maximum dry density Additional Recommendations All erosion and sedimentation shall be controlled in accordance with sound engineering practice and current state and local requirements. In a dry and undisturbed state, the upper one foot of the majority of the soil at the site will provide good subgrade support for fill placement and construction operations. However, when wet, these soils will degrade quickly with disturbance from contractor operations. Therefore, good site Page 16

21 drainage should be maintained during earthwork operations, which will help maintain the integrity of the soil. The surface of the site should be kept properly graded in order to enhance drainage of the surface water away from the proposed structural areas during the construction phase. We recommend that an attempt be made to enhance the natural drainage without interrupting its pattern. Care must be exercised prior to, during and after construction to prevent erosion effects or undermining of foundations. The integrity of the raised building "pad" must hence be maintained for a distance of at least five feet beyond the foundation edges, with gutters disposing of rainfall runoff beyond the pad limits. Foundation concrete should not be cast over a foundation surface containing topsoil or organic soils, trash of any kind, surface made muddy by rainfall runoff, or groundwater rise, or loose soil caused by excavation or other construction work. Reinforcing steel should also be clean at the time of concrete casting. If such conditions develop during construction, the reinforcing steel must be lifted out and the foundation surface reconditioned and approved by the Foundation Engineer Quality Control In order to verify the contractor's compliance with the above recommendations, we should be requested to inspect earthwork operation in order to verify that foundation bearing conditions are consistent with our expectations. 4.5 BORROW AND ON-SITE SOIL SUITABILITY Fine sand (SP) can be utilized as structural and pavement subgrade fill material provided that the natural moisture content is within a desirable range to obtain compaction. Fine sand with silt (SP-SM) or fine sand with clay (SP-SC) can be utilized as structural and pavement subgrade fill material provided that the natural moisture content is within a desirable range to obtain compaction. It should be noted that due to higher fine content, soil may be more sensitive to moisture changes and may require more handling. Clayey fine sand (SC) and silty fine sand (SM) are more difficult to use as fill because they are more moisture sensitive. These soils may be utilized under the building and pavement areas with a minimum of 3 feet of fine sand (SP) topping over the silty/clayey soil. All materials to be used for backfill or compacted fill construction should be evaluated and, if necessary, tested by NOVA prior to placement to determine if they are suitable Page 17

22 for the intended use. In general, based upon the boring results, the near surface sands such as those encountered in the borings within the top 2 feet of the subsurface can be used as a structural fill as well as general subgrade fill and backfill, provided that the fill material is free of rubble, clay, rock, roots and organics. In the proposed storm water pond area in the Crews Park, soils encountered in the top 20 feet of the subsurface are suitable for the use of structural fill as well as general purpose fill except the organic soils encountered between 2 and 7 feet (bgs). Any off-site materials used as fill should be approved by NOVA prior to acquisition. Suitable structural fill materials should generally consist of fine to medium sand with less than 12 percent passing the No. 200 sieve, and be free of rubble, organics, clay, debris and other unsuitable material. 4.6 PAVEMENT CONSIDERATIONS Both flexible and rigid pavement sections are suitable for the site. We recommend using a flexible pavement system (asphaltic concrete) for the construction of the paved parking areas and access roadways. We recommend using rigid pavement in dumpster, storage, and service court areas or other areas where truck traffic will be accelerating, decelerating, and turning. Our pavement section recommendations are presented in this section. It should be realized that the pavement recommendations presented below are considered minimum for the site, soil and limited traffic conditions expected. The final pavement thickness design should be determined by the project Civil Engineer using information obtained from the subsurface exploration program and an analysis of anticipated traffic conditions Flexible Pavement The following flexible pavement sections have been established using the Flexible Pavement Design Manual as published by the Florida Department of Transportation. Please note that flexible pavement sections are not recommended for areas where truck traffic will be accelerating, decelerating or turning. Pavement Area Standard Duty (Parking) Heavy Duty (Driveway and Access Road) FLEXIBLE PAVEMENT SECTION Stabilized Limerock/ Subbase Type Crushed Concrete B Base Asphaltic Concrete (SP-12.5 and/or FC- 9.5) 12 inches 6 inches 1.5 inches 12 inches 8 inches 2.0 inches Page 18

23 The preceding flexible pavement section recommendations are based on an assumed Limerock Bearing Ratio (LBR) value for the compacted subgrade of 20. LBR test was not performed in the current study. Based on our experience with similar materials in the general area of the site, the on-site sandy soils should have a LBR value of at least 20% after compaction/densification. This LBR value should be confirmed through testing during the construction stage of the project. The asphaltic concrete should be constructed using structural course of Type SP-12.5 and/or friction course of Type FC-9.5. The asphaltic concrete should meet standard FDOT material requirements and placement procedures as outlined in the current FDOT Standard Specifications for Road and Bridge Construction. The asphalt should be compacted to a minimum range of 95% of the Marshall maximum laboratory unit weight. The following recommendations are provided for pavement construction: 1. Proofroll the exposed stripped natural subgrade and compact to at least 95% of the Modified Proctor maximum dry density (ASTM D1557). 2. Provide the recommended Type B stabilized subgrade section. The stabilized soils should be compacted to at least 95% density (ASTM D1557), and should possess a Limerock Bearing Ratio of at least 40 percent. 3. Provide the recommended thickness base section consisting of limerock or crushed concrete base course materials (minimum LBR of 100 percent). Compact in-place to a minimum 98% density (ASTM D1557). Install per Florida Department of Transportation specifications. 4. Provide the recommended thickness of asphalt pavement. A qualified soil engineering technician under the direction of a registered professional geotechnical engineer should observe placement and compaction of the pavement materials and perform density tests to confirm that the materials have been placed in accordance with our recommendations. The natural soils, stabilized base, and limerock/crushed concrete materials should conform to applicable sections of the State of Florida, Department of Transportation Standard Specifications for Road and Bridge Construction. In addition, all asphalt material and paving operations should meet applicable specifications of the Asphalt Institute and Florida Department of Transportation. The following sections are referenced: Type B Stabilization: Section 160 Stabilizing, Section 914 Materials for Subgrade Stabilization Page 19

24 Asphalt Structural Course: Section 334 Superpave Asphalt Concrete Asphalt Friction Course: Section 337 Asphalt Concrete Friction Courses Rigid Pavement Based on assumed low volume, traffic loading and the assumed estimated subgrade modulus (k) of 125 pci for traffic or wheel loading where slabs bear upon at least 4 inches of compacted GAB, we recommend a 5-inch for standard duty and a 6-inch concrete slab for heavy duty concrete pavement sections. All concrete joints should conform to applicable FDOT specifications. We recommend that a non-woven geo-textile (about 3 feet wide) be placed beneath the construction joints to prevent upward "pumping movement of soil fines through the joints. Rigid Pavement Subgrade: For a rigid (concrete) pavement subgrade, the following stipulations should apply: The surface of the subgrade soils must be smooth, and any disturbances or wheel rutting corrected prior to placement of concrete. The subgrade soils must be moistened prior to placement of concrete. Concrete pavement thickness should be uniform throughout, with exception to thickened edges (curb or footing). The bottom of the pavement should be separated from the estimated typical wet season groundwater level by at least 18 inches. STANDARD DUTY RIGID PAVEMENT SECION (AUTO PARKING/DRIVE) Minimum Pavement Thickness Maximum Control Joint Spacing Recommended Saw- Cut Depth 5 Inches 10 feet x 10 feet 1½ Inches HEAVY DUTY RIGID PAVEMENT SECION (TRUCK PARKING/DRIVE) Minimum Pavement Thickness Maximum Control Joint Spacing 6 Inches 12 feet x 12 feet 2 Inches Recommended Saw- Cut Depth We recommend using concrete with a minimum compressive strength of 4000 psi and a minimum 28-day flexural strength (modulus of rupture) of at least 600 pounds per Page 20

25 square inch, based on 3 rd point loading of concrete beam test samples. Layout of the saw-cut control joints should form square panels, and the depth of saw-cut joint should be ¼ of the concrete slab thickness. The joints should be sawed within six hours of concrete placement or as soon as the concrete has developed sufficient strength to support workers and equipment. We recommend allowing NOVA to review and comment on the final concrete pavement design, including section and joint details (type of joints, joint spacing, etc.), prior to the start of construction. For further details on concrete pavement construction, please reference the Guide to Jointing on Non-Reinforced Concrete Pavements published by the Florida Concrete and Products Associates, Inc., and Building Quality Concrete Parking Areas, published by the Portland Cement Association. Please note that the recommended pavement section is based on assumed postconstruction traffic loading. If the pavement is to be constructed and utilized by construction traffic, the above pavement section will likely prove insufficient for heavy truck traffic, such as concrete trucks or tractor-trailers used for construction delivery. Unexpected distress, reduced pavement life and /or pre-mature failure of the pavement section could result if subjected to heavy construction traffic and the owner should be made aware of this risk. If the assumed traffic loading stated herein is not correct, NOVA should review actual pavement loading conditions to determine if revisions to these recommendations are warranted. Page 21

26 APPENDIX A. FIGURES FIGURE 1: FIELD EXPLORATION PLAN

27 B-1 B-4 B-3 B-2 B-5 P-1 B-1 Soil Test Borings B1 B2 to 20, B3 B5 to 10 P-1 Open-Hole Percolation Test N Scale: As Shown Figure 1. Field Exploration Plan Date Drawn: 05/22/2017 Crews Park at Peace River Drawn By: TM 130 Park Drive Wauchula, FL Checked By: JJC NOVA Project Number:

28 APPENDIX B. TEST BORING RECORDS UNIFIED SOIL CLASSIFICATION SYSTEM FIELD CLASSIFICATION FOR SOIL EXPLORATION TEST BORING RECORDS

29 KEY TO SYMBOLS AND CLASSIFICATIONS DRILLING SYMBOLS Split Spoon Sample Undisturbed Sample (UD) Standard Penetration Resistance (ASTM D ) Water Table at least 24 Hours after Drilling Water Table 1 Hour or less after Drilling 100/2 Number of Blows (100) to Drive the Spoon a Number of Inches (2) NX, NQ Core Barrel Sizes: 2⅛ and 2 Inch Diameter Rock Core, Respectively REC Percentage of Rock Core Recovered RQD Rock Quality Designation Percentage of Recovered Core Segments 4 or more Inches Long Loss of Drilling Water MC Moisture Content Test Performed CORRELATION OF PENETRATION RESISTANCE WITH RELATIVE DENSITY AND CONSISTENCY SANDS SILTS and CLAYS Number of Blows, N Approximate Relative Density 0 4 Very Loose 5 10 Loose Medium Dense Dense Over 50 Very Dense Number of Blows, N Approximate Consistency 0 2 Very Soft 3 4 Soft 5 8 Firm 9 15 Stiff Very Stiff Hard Over 50 Very Hard DRILLING PROCEDURES Soil sampling and standard penetration testing performed in accordance with ASTM D The standard penetration resistance is the number of blows of a 140 pound hammer falling 30 inches to drive a 2 inch O.D., 1⅖inch I.D. split spoon sampler one foot. Core drilling performed in accordance with ASTM D T. The undisturbed sampling procedure is described by ASTM D Soil and rock samples will be discarded 60 days after the date of the final report unless otherwise directed.