PCN_98985_Geotechnical_Report.pdf

MEMBERS:

A.S.F.E.

American Concrete Institute ASTM International

Florida Institute of Consulting Engineers

Subsurface Soil Exploration and Geotechnical Engineering Evaluation

LH2 System Upgrade Design Kennedy Space Center, Florida

Ardaman & Associates, Inc.

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Ardaman & Associates, Inc.

Geotechnical, Environmental and Materials Consultants

File No. 16-23-5258

January 10, 2017

Revised January 30, 2017

BRPH

5700N. Harbor City Boulevard, Suite 400

Melbourne, Florida 32940

Attention: Ms. Diana Cheung, P.E.

Subject: Subsurface Soil Exploration and

Geotechnical Engineering Evaluation

LH2 System Upgrade Design

Kennedy Space Center, Florida

BRPH Project No. 7077.003

PO #15057

Dear Ms. Cheung:

As requested and authorized by you, we have completed a shallow subsurface soil exploration and geotechnical engineering evaluation for the subject project. The purposes of performing this exploration were to evaluate the general subsurface conditions within the proposed structure areas and to provide recommendations for site preparation and foundation support. In addition, we have estimated the normal seasonal high groundwater level at the boring locations. This report documents our findings and presents our engineering recommendations.

SITE LOCATION AND SITE DESCRIPTION

The site of the proposed LH2 System improvements is located on the northeast quadrant of the

LC 39B facility on Kennedy Space Center in Brevard County, Florida. This site is located in

Section 28, Township 21 South, Range 37 East. The general project site location is shown superimposed on the Wilson, Florida USGS quadrangle map presented on Figure 1.

A few small structures exists primarily on the northeast portion of the project area based on our site observations. The majority of the project site is grassed.

SOIL SURVEY REVIEW

The 1974 Soil Survey for Brevard County, Florida, as prepared by the U.S. Department of

Agriculture (USDA) Soil Conservation Service, was reviewed during our evaluation. Based on review of the Soil Survey, the project site is mapped as the “Urban Land” soil series. A description of this soil type, as obtained from the Soil Survey, is presented below.

Urban land (Ur):

The “Urban land” (Ur) soil consists of areas that are 60 to more than 75 percent covered with

File No. 16-23-5258 -2-streets, buildings, large parking lots, shopping centers, industrial parks, airports, and related facilities. Unoccupied areas, mostly lawns, parks, vacant lots, and playgrounds; are Astatula, Paola, Myakka, St. Lucie, Immokalee, Pomello, Cocoa, and Canaveral soils in tracts too small to be mapped separately.

PROPOSED CONSTRUCTION AND GRADING

It is our understanding that the proposed construction includes the following:

An 84-foot diameter LH2 Dewar Structure (LH2 Sphere) - supported on a 100-foot wide mat foundation or on auger cast piles.

LH2 Flare Stack - supported on a shallow mat foundation with guy wires.

Flare Stack piping - supported on shallow strip foundations and stem walls.

One-story electrical equipment building - supported on shallow spread foundations.

Grading plans are not complete at this time; therefore, we have assumed that approximately 1 to

2 feet of fill is required to raise the structure areas to final elevation(s). Typical loading conditions for the strip foundations to support the new flare stack piping are assumed to be on the order of

5 to 6 kips per lineal foot (klf). Typical loading conditions for the one-story electrical equipment building are assumed to be on the order of 2 to 3 klf for wall foundations and 30 to 40 kips for individual column foundations.

Information regarding the potential mat foundations for the LH2 Dewar and Flare Stack structures was provided by Mr. Stephen Thomas, P.E. with BRPH on January 5, 2017. Based on the provided information, the LH2 Dewar structure mat foundation will be an octagonal shaped mat with a width of approximately 100 feet and a depth of embedment of 3’-4”. The Flare Stack mat foundation will be approximately 10 feet square with a similar depth of embedment.

The anticipated average mat foundation soil contact pressures for the LH2 Dewar structure are

1,400 pounds per square foot (psf) for a 14-foot wide strip along the perimeter of the foundation and less than 700 psf for the remaining with the interior portion of the foundation based on the information provided by Mr. Thomas. The provided average mat foundation soil contact pressure for the LH2 Flare Stack structure is 800 psf.

If actual structure foundation loads or fill height exceed our assumptions or the provided values, then the recommendations in this report may not be valid.

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FIELD EXPLORATION PROGRAM

SPT Borings

The field exploration program included performing seven Standard Penetration Test (SPT) borings within the areas of the proposed improvements. A summary of where the SPT borings were conducted, as well as the boring depths, is presented in the following table.

Boring ID Location Boring Depth

(ft)

TH-1, TH-2

LH2 Dewar Structure and Vicinity of

Electrical Equipment Building

TH-3 LH2 Flare Stack 80

TH-4, TH-5, and TH-6 Possible Guy Wire Anchor and Flare

Stack Piping Locations 20 and 30

TH-7

Possible Guy Wire Anchor Location and Vicinity of Electrical Equipment

Building

The borings were advanced using the methodology outlined in ASTM D-1586. A summary of this field procedure is included in Appendix I. Split-spoon soil samples recovered during performance of the borings were visually classified in the field and representative portions of the samples were transported to our laboratory in sealed sample jars.

The groundwater level at each of the boring locations was measured during drilling. Upon completion, SPT Borings TH-1 through TH-3 were grouted with neat cement grout and Borings

TH-4 through TH-7 were backfilled with soil cuttings.

Test Locations

The approximate locations of the borings are schematically illustrated on a site plan shown on

Figure 2. These locations were determined in the field by wheel measurements and estimating distances from existing site features and should be considered accurate only to the degree implied by the method of measurement used.

LABORATORY PROGRAM

Representative soil samples obtained during our field sampling operation were packaged and transferred to our laboratory for further visual examination and classification. The soil samples were visually classified in general accordance with the Unified Soil Classification System (ASTM

D-2488). The resulting soil descriptions are shown on the soil boring profiles presented in

Appendix II.

In addition, we conducted one organic content test (ASTM D2974-87), four natural moisture content tests (ASTM D2216), 10 percent fines analyses (ASTM D1140), and one Atterberg limits

File No. 16-23-5258 -4-test (ASTM D4318) on selected soil samples obtained from the borings. The results of these tests are presented adjacent to the sample depth on the soil boring profiles in Appendix II.

GENERAL SUBSURFACE CONDITIONS

General Soil Profile

The results of the field exploration and laboratory programs are graphically summarized on the soil boring profiles presented in Appendix II. The stratification of the boring profiles represents our interpretation of the field boring logs and the results of laboratory examinations of the recovered samples. The stratification lines represent the approximate boundary between soil types. The actual transitions may be more gradual than implied.

The results of the borings indicate the following general soil profile at the project site:

Depth Below Ground

Surface (feet) Description (Unified Soil Classification)

0 to 17.5

Very loose to very dense fine sand (SP), fine sand with silt (SP-SM), silty fine sand (SM), and clayey fine sand

(SC)

17.5 to 37.5 Medium dense to dense fine sand (SP)

37.5 to 47.5 Very loose to dense fine sand (SP), silty fine sand (SM), and clayey fine sand (SC)

47.5 to 57.5 Medium dense to very dense fine sand (SP) and fine sand with silt (SP-SM)

57.5 to 80

Loose to medium dense clayey fine sand (SC) and silty/clayey fine sand (SM-SC), with partially-cemented sand and shell from 62.5 to 72.5 feet

Various amounts of shell were noted in many of the soil samples collected from the borings. The above soil profile is outlined in general terms only. Please refer to the soil boring profiles in

Appendix II for soil profile details.

Groundwater Level

The groundwater level was measured in the boreholes on the day drilled. As shown on the soil boring profiles in Appendix II, groundwater was encountered at depths that ranged from 2.6 to 4.2 feet below the existing ground surface on the date indicated. Fluctuations in groundwater levels should be anticipated throughout the year primarily due to seasonal variations in rainfall and other factors that may vary from the time the borings were conducted.

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NORMAL SEASONAL HIGH GROUNDWATER LEVEL

The normal seasonal high groundwater level each year is the level in the August-September period at the end of the rainy season during a year of normal (average) rainfall. The water table elevations associated with a higher than normal rainfall and in the extreme case, flood, would be higher to much higher than the normal seasonal high groundwater level. The normal high water levels would more approximate the normal seasonal high groundwater levels.

The seasonal high groundwater level is affected by a number of factors. The drainage characteristics of the soils, the land surface elevation, relief points such as drainage ditches, lakes, rivers, swamp areas, etc., and distance to relief points are some of the more important factors influencing the seasonal high groundwater level.

In addition to evaluating the conditions above, we have reviewed annual precipitation data available from the Melbourne Office of the National Weather Service. Based on this data, the rainfall to date in Brevard County upon completion of the field exploration program is approximately 59.5 inches, which is approximately 8.2 inches above normal for this time of year.

Based on our interpretation of the site conditions using our boring logs, we estimate the normal seasonal high groundwater level at the boring locations to be approximately 1½ feet above the groundwater levels measured at the time of our field exploration. The groundwater level may temporarily perch at higher levels during or after heavy or prolonged rainfall due to the shallow silty and clayey fine sand soils present at the site.

ENGINEERING EVALUATION AND RECOMMENDATIONS

General

The results of our exploration will indicate that, with proper site preparation as recommended in this report, the existing soils are suitable for supporting the proposed structures on conventional shallow foundation systems (i.e. spread footings and/or a mat foundation). These recommendations for shallow foundations are applicable provided that the calculated settlements, as presented in the following report sections, are deemed acceptable. If so, spread footings and/or a mat foundation should provide an adequate support system for the structures. If the calculated settlements are deemed unacceptable, then an alternative deep foundation system (i.e. piles) or deep soil improvement may be required. Recommendations for deep pile foundations for the LH2 Dewar Structure have been included in a subsequent section of this report.

The following are our recommendations for overall site preparation and foundation support which we feel are best suited for the proposed facilities and existing soil conditions. The recommendations are made as a guide for the design engineer, parts of which should be incorporated into the project's specifications.

Stripping and Grubbing

The "footprints" of the proposed structure areas, plus a minimum margin of 5 feet, should be stripped of all surface vegetation, stumps, debris, asphalt, concrete, organic topsoil or other deleterious materials, as encountered. Buried utilities should be removed or plugged to eliminate conduits into which surrounding soils could erode.

File No. 16-23-5258 -6-

After stripping, the site should be grubbed or root-raked such that roots with a diameter greater than ½ inch, stumps, or small roots in a dense state, are completely removed. The actual depth(s) of stripping and grubbing must be determined by visual observation and judgment during the earthwork operation.

All existing foundations, slabs and any other underground structures should be removed from the proposed construction areas. If pipes or any collapsible or leak prone utilities are not removed or completely filled (with grout or concrete), they might serve as conduits for subsurface erosion resulting in excessive settlements. Over-excavated areas resulting from the removal of underground structures and unsuitable materials should be backfilled in accordance with the fill soils section of this report.

It has been our experience that soils surrounding existing structures sometimes contain pockets of construction debris or other deleterious materials requiring removal and replacement with compacted clean fine sands. Therefore, we strongly recommend that the stripped surface be inspected by Ardaman & Associates, Inc.

Proof-rolling

We recommend proof-rolling the cleared surface to locate any unforeseen soft areas or unsuitable surface or near-surface soils, to increase the density of the upper soils, and to prepare the existing surface for the addition of the fill soils (as required). Proof-rolling of the structure areas should consist of at least 10 passes of a compactor capable of achieving the density requirements described in the next paragraph. Each pass should overlap the preceding pass by 30 percent to achieve complete coverage. If deemed necessary, in areas that continue to "yield", remove all deleterious material and replace with clean, compacted sand backfill. The proof-rolling should occur after cutting and before filling.

A density equivalent to or greater than 95 percent of the modified Proctor (ASTM D-1557) maximum dry density value for a depth of 2 feet in the structure areas must be achieved beneath the stripped and grubbed ground surface. Additional passes and/or overexcavation and recompaction may be required if these minimum density requirements are not achieved. The soil moisture should be adjusted as necessary during compaction.

Due to the relatively high groundwater level at this site, proof-rolling may cause upward movement or "pumping" of the groundwater. However, we recommend that the existing surface be level and firm prior to the addition of fill soils. Proof-rolling with a front-end loader may help achieve the desired surface and compaction condition before adding the fill soils. The site should be dewatered as necessary. Depending on the time of year, a 12- to 18-inch layer of clean fine sand

(SP) fill may be required prior to proof-rolling.

Care should be exercised to avoid damaging any neighboring structures while the compaction operation is underway. Prior to commencing compaction, occupants of adjacent structures should be notified and the existing condition (i.e. cracks) of the structures documented with photographs and survey (if deemed necessary). If requested, Ardaman & Associates could assist with pre- and post-construction surveys of existing structures and with vibration monitoring during construction.

Compaction should cease if deemed detrimental to adjacent structures, and Ardaman &

File No. 16-23-5258 -7-

Associates should be notified immediately. Heavy vibratory compaction equipment should not be used within 200 feet of existing structures.

Suitable Fill Material and the Compaction of Fill Soils

All fill soil should be free of organic materials, such as roots and vegetation. We recommend using fill with less than 12 percent by dry weight of material passing the U.S. Standard No. 200 sieve size. The fine sand and fine sand with silt (Strata Nos. 1 and 2 without roots, as shown on the soil boring profiles presented in Appendix II) are suitable for use as fill soil and, with proper moisture control, should densify using conventional compaction methods. Soils with more than 12 percent passing the No. 200 sieve can be used in some applications, but will be more difficult to compact due to their inherent nature to retain soil moisture.

All structural fill should be placed in level lifts not to exceed 12 inches in uncompacted thickness.

Each lift should be compacted to at least 95 percent of the modified Proctor (ASTM D-1557) maximum dry density value. The filling and compaction operations should continue in lifts until the desired elevation(s) is achieved. If hand-held compaction equipment is used, the lift thickness should be reduced to no more than 6 inches.

Foundation Support by Shallow Spread Footings and Foundation Compaction Criteria –

Electrical Equipment Building and Flare Stack Piping

Excavate the foundations to the proposed bottom of footing elevations and, thereafter, verify the in-place compaction for a depth of 2 feet below the footing bottoms. If necessary, compact the soils at the bottom of the excavations to at least 95 percent of the modified Proctor maximum dry density (ASTM D-1557) for a depth of 2 feet below the footing bottoms.

Based on the existing soil conditions and, assuming the above outlined proof-rolling and compaction criteria are implemented, an allowable soil bearing pressure of 2,000 pounds per square foot (psf) may be used in the foundation design for the one-story Electrical Equipment

Building and the Flare Stack Piping. This bearing pressure should result in foundation settlement within tolerable limits (i.e., 1 inch or less).

All continues foundations should be a minimum of 18 inches wide and column foundations 24 inches wide. A minimum soil cover of 18 inches should be maintained from the bottom of the shallow spread foundations to the adjacent finished grades.

Floor Slab Moisture Reducer and Slab Compaction Requirements

Compaction beneath all floor slabs should be verified for a depth of 12 inches and meet the 95 percent criteria (modified Proctor, ASTM D-1557). A modulus of subgrade reaction of 150 pounds per cubic inch (pci) may be used for slab design.

Precautions should be taken during the slab construction to reduce moisture entry from the underlying subgrade soils. Moisture entry can be reduced by installing a membrane between the subgrade soils and floor slab. Care should be exercised when placing the reinforcing steel (or mesh) and slab concrete such that the membrane is not punctured. We note that the membrane alone does not prevent moisture from occurring beneath or on top of the slab.

File No. 16-23-5258 -8-

If interior columns are isolated from the floor slab, an expansion joint should be provided around the columns and sealed with a water-proof sealant.

Mat Foundation Support and Foundation Compaction Criteria – Option for LH2 Dewar Structure and for LHS Flare Stack Structure

It is our understanding that consideration is being given to founding the LH2 Dewar structure and the LH2 Flare Stack structure on mat foundations. The following recommendations are contingent upon the magnitude of calculated settlement being acceptable to the design team. If not acceptable, then pile foundations or deep soil improvement may be required.

Excavate the structure foundations to the proposed bottom of mat elevation and, thereafter, verify the in-place compaction for a depth of 2 feet below the bottom of the mat. If necessary, compact the bottom of the excavation to achieve a minimum dry density equivalent to 95 percent of the modified Proctor maximum dry density (ASTM D-1557) for a depth of 2 feet below the bottom of the mat.

Settlement analyses for the proposed mat foundations were performed using the computer program Settle 3D, the provided mat dimensions for both structures, the provided average mat soil contact pressures, and the results of our field exploration. For the purpose of performing the settlement analysis using the software, the LH2 Dewar structure foundation was modeled as a circular foundation with a diameter of 100 feet. For the sandy soils encountered, published correlations relying on the SPT N-values were used to estimate the elastic moduli. The Westergard stress distribution method was used for calculating the stress changes caused by the estimated weight of the proposed structure in the underlying foundation soils.

The results of the mat foundation settlement analyses for the two structures are summarized in the following table.

Structure

Average Mat Foundation Contact

Pressure (psf)

Estimated Total Mat Settlement

(inches)

Estimated Differential Mat

Settlement (inches)

LH2 Dewar Structure 1,400 (perimeter “ring”), 700 for remainder 1½ (at perimeter

“ring”) ¾

LH2 Flare Stack

800 <1 (at center) <½

It is estimated that the majority (approximately 70 percent) of the calculated settlement will occur during construction as the loads are applied.

Foundation Support by Deep Auger Cast Pile Foundations – Option for LH2 Dewar

When considering the installation of auger cast piles, the designer should realize that the load capacity of the completed pile is dependent upon the skill and care exercised by the Contractor.

We recommend a detailed specification be developed for their installation.

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We have analyzed allowable compressive capacities for 16- and 18-inch augered cast-in-place piles (auger cast or ACIP). Static pile capacities were estimated utilizing SPT N-values from

Borings TH-1 and TH-2 for this study. Specifically, the computer software program “FB-Deep”, which utilizes procedures developed by Dr. Schmertman. A summary of the results of the axial pile capacities analyses versus tip depths are presented in the table below.

Pile Type Pile Tip Depth

(feet below existing grade)

Allowable Axial Compressive

Capacity (tons)

16” ACIP

25 16

30 23

35 29

40 37

45 44

50 50

55 58

60 65

18” ACIP

25 19

30 26

35 33

40 41

45 50

50 57

55 65

60 73

The calculated allowable capacities presented in the table above are based on a factor of safety of 2, and are developed by skin friction along the length of the pile plus end bearing. A factor of safety of 2 is typically used when static load compression testing is performed to verify capacity.

Minimum pile spacing should be 3.0 pile diameters from center to center of the piles in a group to prevent group interaction which could result in a loss of some of the capacity of an individual pile.

Capacities must be verified in the field by actual load tests, and pile size and length adjusted, if necessary. Allowable tension capacities per individual pile are calculated to be at least 35 percent of the calculated axial capacities presented in the preceding table.

Care should be taken to maintain the vertical and horizontal alignment of the piles. We recommend that the concrete grout used to form the piles reach a compressive strength of at least 5,000 psi in 28 days.

The lower five feet of the pile borehole should be double-reamed and double-pumped. That is, once the auger reaches the specified depth, the grout pumping should commence, and the auger should be retrieved a height of 3 to 5 feet, and then reinserted to the bottom of the pile while the grout is being pumped. Once the auger is reinserted to the bottom of the pile, it may be retrieved slowly to the ground surface as the grout is being pumped.

The amount of concrete grout used to form each pile should be at least 1.2 times the theoretical pile volume. At a minimum, this calculated volume of grout is to be pumped per foot of pile as the auger is retrieved. The Contractor will need to install each pile such that an adequate cross section is maintained.

Piles should not be installed within 10 pile diameters, center to center, of a pile filled with grout

File No. 16-23-5258 -10-that is less than 24 hours old. If grout heave occurs at a nearby pile, this distance must be increased to a sufficient distance so that the installation of adjacent piles does not affect grout set or pile geometry.

If grout pumping and/or auger retrieval operations are stopped at any time during the formation of a given pile, the borehole is to be reaugered and the pile formed anew. If the concrete level in any completed pile drops, the pile shall be rejected and replaced. If there is difficulty in placing the reinforcement steel in any pile, the pile shall be redrilled and replaced. All reinforcement steel should be fitted with spacers including a spacer at its lower tip to allow easier installation into the pile and assure its centering. Reinforcement must extend the full depth of the pile through which tension resistance is needed. However, deep reinforcement should consist of 1 or 2 bars clustered in the center of the pile. Steel reinforcement cages, if needed, should be limited in size and depth.

Any modification to these procedures is to be approved by the Geotechnical Engineer based on observations during pile installation.

We recommend conducting a minimum of one static load compression test in accordance with ASTM D-1143 (Quick Load Test Method) at a non-production pile location prior to commencing production pile installation to finalize the load capacity and pile length requirement. The test load should be at least twice the design load. The contractor should supply the load test set up and jacking equipment. Ardaman & Associates, Inc. will provide the gauges and reference beams and monitor pile vertical movements. The contractor’s jack and pump must be calibrated just prior to the load test, by a certified laboratory and the results of the calibration must be provided to Ardaman prior to the pile load test.

The results of the load test along with the load test pile installation methodology will be used to establish the methodology of pile installation for production piles. Actual production pile lengths may be longer than those presented in the axial capacity table presented above pending the results of the load test.

In addition, we recommend that low strain pile integrity testing be conducted on some of the auger cast piles prior to acceptance. The number of piles to be tested will depend on the contractor’s installation and site operation procedures, but at a minimum, 20 percent of the piles should be tested.

Dewatering

If the control of groundwater is required to achieve the necessary stripping, excavation, proof-rolling, filling, compaction, and any other earthwork, sitework, and/or foundation subgrade preparation operations required for the project, the actual method(s) of dewatering should be determined by the contractor. Dewatering should be performed to lower the groundwater level to depths that are adequately below excavations and compaction surfaces. Adequate groundwater level depths below excavations and compaction surfaces vary depending on soil type and construction method, and are usually 2 feet or more. Dewatering solely with sump pumps may not achieve the desired results.

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Resistance to Horizontal Forces on Guy Wire Anchors

Horizontal forces which act on structures (such as the guy wire anchors) can be resisted to some extent by the earth pressures that develop in contact with the buried vertical face (bearing vertical face is perpendicular and in front of the applied horizontal load) of the structure and by shearing resistance mobilized along the base of the structure and subgrade interface. Allowable earth pressure resistance may be determined using equivalent fluid densities for moist and submerged soils determined using the formulas presented below 1 . The passive earth pressures are developed from ground surface to the bottom of the structure (assuming there is no excavation in the vicinity of the structure that would reduce the available passive pressure).

The equivalent fluid density values determined using the formulas presented below presume that the structure is surrounded by well compacted sand backfill extending at least 5 feet horizontally beyond the vertical bearing face. In addition, it is presumed that the structure can withstand horizontal movements on the order of one-quarter (¼) to three-eighths (⅜) inch before mobilizing full passive resistance. Appropriate factors of safety for passive pressure with moist and submerged (saturated) conditions should be selected by the design engineer and applied to the equivalent fluid density formulas presented below. If requested, Ardaman & Associates can assist with the evaluation of appropriate factors of safety.

The shearing resistance mobilized along the base of the structure may be determined by the following formula:

Shearing Resisting Force, P=V tan(2/3Φ)

Where:

P = Shearing Resistance Force (pounds) V = Net Vertical Force (total weight of structure and soil overlying the structure minus uplift forces including buoyancy forces) (pounds) Φ = Angle of Internal Friction of Soil = 32 degrees

The vertical earth pressures developed by the overburden weight of soil can be calculated using the following unit weights:

● Compacted moist soil = 110 pcf

● Saturated soil = 120 pcf

1Equivalent fluid density (moist soil) = Kp γm/S.F.

Equivalent fluid density (submerged soil) = Kp(γs- γw)/S.F.

Where:

Kp = effective coefficient of passive earth pressure = 2.7 S.F. = safety factor (as directed by client, an appropriate safety factor to be selected by design engineer) γm= unit weight of moist soil = 110 pcf γs = unit weight of saturated soils = 120 pcf γw = unit weight of water = 62 pcf

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For design, an appropriate safety factor should be applied to the shearing resistance force calculated using the preceding Shearing Resisting Force equation.

Vertical pressure distributions in accordance with the above do not take into account vertical forces from construction equipment, wheel loads or other surcharge loads.

At-Rest Earth Pressures Acting on Buried Structures

At-rest pressures acting on embedded or buried structures include lateral loading due to soil, water and surcharge, if any. The lateral earth pressure will be a function of both the soil unit weight (submerged) and the depth below the ground surface. The following equation can be used to determine the lateral at-rest earth pressure:

Ph = Koγh

Where:

Ph = lateral at-rest earth pressure (psf)

Ko = coefficient of at-rest earth pressure (0.5) (this value assumes that the backfill is lightly compacted yet not overcompacted) γ = unit weight of soil (γm for moist soil above the water table and γb for saturated soil below the water table) γm = effective moist unit weight of soil = 110 pcf for compact moist soil above the water table γb = buoyant unit weight of soil = 60 pcf for compacted saturated soil below the water table h = depth (feet) below grade at which lateral earth pressure is determined

For design, an appropriate safety factor should be applied to the lateral at-rest earth pressure determined in accordance with the above equation.

In addition, lateral pressure distributions determined in accordance with the above equation do not include hydrostatic pressures or surcharge loads. Where applicable, they should be incorporated in the design.

QUALITY ASSURANCE

We recommend establishing a comprehensive quality assurance program to verify that all site preparation and foundation construction is conducted in accordance with the appropriate plans and specifications. Materials testing and inspection services should be provided by Ardaman &

Associates.

As a minimum, an on-site engineering technician should monitor all stripping and grubbing to verify that all deleterious materials have been removed and should observe the proof-rolling operation to verify that the appropriate number of passes are applied to the subgrade. In-situ density tests should be conducted during filling activities and below all foundations and floor slabs to verify that the required densities have been achieved. In-situ density values should be compared to laboratory Proctor moisture-density results for each of the different natural and fill soils encountered.

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The installation of test and production piles should be monitored full-time by a representative of

Ardaman & Associates. Finally, we recommend inspecting and testing the construction materials for the foundations and other structural components.

IN-PLACE DENSITY TESTING FREQUENCY

In Central Florida, earthwork testing is typically performed on an on-call basis when the contractor has completed a portion of the work. The test result from a specific location is only representative of a larger area if the contractor has used consistent means and methods and the soils are practically uniform throughout. The frequency of testing can be increased and full-time construction inspection can be provided to account for variations. We recommend that the following minimum testing frequencies be utilized.

In proposed structural areas, the minimum frequency of in-place density testing should be a minimum of three tests per structural area. In-place density testing should be performed at this minimum frequency for a depth of 2 feet below natural ground and for every 1-foot lift of fill placed in the structural area. In addition, density tests should be performed in each spread footing for a depth of 2 feet below the bearing surface. For continuous or wall footings, density tests should be performed at a minimum frequency of one test for every 50 linear feet of footing, and for a depth of 2 feet below the bearing surface.

Representative samples of the various natural ground and fill soils should be obtained and transported to our laboratory for Proctor compaction tests. These tests will determine the maximum dry density and optimum moisture content for the materials tested and will be used in conjunction with the results of the in-place density tests to determine the degree of compaction achieved.

CLOSURE

The analyses and recommendations submitted herein are based on the data obtained from the soil borings presented on Figure 2 and in Appendix II, as well as the provided and assumed loading conditions and fill heights. This report does not reflect any variations which may occur adjacent to or between the borings. The nature and extent of the variations between the borings may not become evident until during construction. If variations then appear evident, it will be necessary to re-evaluate the recommendations presented in this report after performing on-site observations during the construction period and noting the characteristics of the variations. This study does not include an evaluation of the environmental (ecological or hazardous/toxic material related) condition of the site and subsurface.

This report has been prepared for the exclusive use of BRPH in accordance with generally accepted geotechnical engineering practices. In the event any changes occur in the design, nature, or location of the proposed facility, we should review the applicability of conclusions and recommendations in this report. We recommend a general review of final design and specifications by our office to verify that earthwork and foundation recommendations are properly interpreted and implemented in the design specifications. Ardaman and Associates should attend the pre-bid and preconstruction meetings to verify that the bidders/contractor understand the recommendations contained in this report.

File No. 16-23-5258 -14-

We are pleased to be of assistance to you on this phase of the project. When we may be of further service to you or should you have any questions, please contact us.

Very truly yours, ARDAMAN & ASSOCIATES, INC.

Certificate of Authorization No. 5950

Dan J. Zrallack Jason P. Manning, P.E.

Senior Project Engineer Branch Manager

Florida License No. 63911 Florida License No. 53265

DJZ/JPM/cm

APPENDIX I

Standard Penetration Test Boring Procedures

STANDARD PENETRATION TEST

The standard penetration test is a widely accepted test method of in situ testing of foundation soils (ASTM D 1586). A 2-foot long, 2-inch O.D. split-barrel sampler attached to the end of a string of drilling rods is driven 18 inches into the ground by successive blows of a 140-pound hammer freely dropping 30 inches. The number of blows needed for each 6 inches of penetration is recorded. The sum of the blows required for penetration of the second and third 6-inch increments of penetration constitutes the test result or N-value. After the test, the sampler is extracted from the ground and opened to allow visual examination and classification of the retained soil sample.

The N-value has been empirically correlated with various soil properties allowing a conservative estimate of the behavior of soils under load.

The tests are usually performed at 5-foot intervals. However, more frequent or continuous testing is done by our firm through depths where a more accurate definition of the soils is required. The test holes are advanced to the test elevations by rotary drilling with a cutting bit, using circulating fluid to remove the cuttings and hold the fine grains in suspension. The circulating fluid, which is a bentonitic drilling mud, is also used to keep the hole open below the water table by maintaining an excess hydrostatic pressure inside the hole. In some soil deposits, particularly highly pervious ones, NX-size flush-coupled casing must be driven to just above the testing depth to keep the hole open and/or prevent the loss of circulating fluid.

Representative split-spoon samples from the soils at every 5 feet of drilled depth and from every different stratum are brought to our laboratory in air-tight jars for further evaluation and testing, if necessary. Samples not used in testing are stored for 30 days prior to being discarded. After completion of a test boring, the hole is kept open until a steady state groundwater level is recorded. The hole is then sealed, if necessary, and backfilled.

APPENDIX II

Soil Boring Profiles