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Geotechnical Engineering ReportTampa Convention Center – Elevator Addition

Tampa, Hillsborough County, FloridaMay 25, 2018

Terracon Project No. H4185065

Prepared for:ADS | SKY

Tampa, Florida

Prepared by:Terracon Consultants, Inc.

Tampa, City

Terracon Consul tants, Inc. 5463 W. Waters Avenue, Sui te 830 Tampa, F lor ida 33634P [813] 221 0050 F [813] 221 0051 terracon.com

REPORT COVER LET TER T O SIGN

May 25, 2018

ADS | SKY1240 East 5th AvenueTampa, Florida 33605

Attn: Mr. John Curran, AIAP: 813.341.6810E: [email protected]

Re: Geotechnical Engineering ReportTampa Convention Center – Elevator AdditionTampa, FloridaTerracon Project No. H4185065

Dear Mr. Curran:

We have completed the Geotechnical Engineering services for the above referenced project. Thisstudy was performed in general accordance with Terracon Proposal No. PH4185065R dated April24, 2018. This report presents the findings of the subsurface exploration and provides geotechnicalrecommendations concerning earthwork and the design and construction of foundation options. Wepreviously provided a letter report which presented the findings of our two Double Ring Infiltration(DRI) tests, provides our estimate for a seasonal high groundwater table at the subject sites. Inaddition, the letter report provided the results of our hand augers which were performed adjacentto our DRI tests.

We appreciate the opportunity to be of service to you on this project. If you have any questionsconcerning this report, or if we may be of further service, please contact us.

Sincerely,Terracon Consultants, Inc.

James K. Nesbitt, P.E. Keith D. Bennett, P.E.Geotechnical Project Engineer Senior EngineerFL Registration No. 74603 FL Registration No. 33075

This report has been electronically signed and sealed by James K. Nesbitt, P.E. on 5/25/18 using a Digital Signature.Printed copies of this document are not considered signed and sealed and the signature must be verified on any electronic copies.

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REPORT TOPICSREPORT TOPICS

REPORT SUMMARY ....................................................................................................... IINTRODUCTION ............................................................................................................. 1SITE CONDITIONS ......................................................................................................... 1PROJECT DESCRIPTION .............................................................................................. 2GEOTECHNICAL CHARACTERIZATION ...................................................................... 2GEOTECHNICAL OVERVIEW ....................................................................................... 4EARTHWORK................................................................................................................. 4AUXILIARY SHALLOW FOUNDATIONS ....................................................................... 7SPECIALTY DEEP FOUNDATION SYSTEMS............................................................... 8SEISMIC CONSIDERATIONS ...................................................................................... 10LATERAL EARTH PRESSURES ................................................................................. 10GENERAL COMMENTS ................................................................................................. 1

Note: This report was originally delivered in a web-based format. Orange Bold text in the report indicates a referencedsection heading. The PDF version also includes hyperlinks which direct the reader to that section and clicking on the

logo will bring you back to this page. For more interactive features, please view your project online atclient.terracon.com.

ATTACHMENTS

EXPLORATION AND TESTING PROCEDURESSITE LOCATION AND EXPLORATION PLANSEXPLORATION RESULTS (Boring Log and Double Ring Infiltration Results)SUPPORTING INFORMATION (General Notes and Unified Soil Classification System)

Geotechnical Engineering ReportTampa Convention Center – Elevator Addition ■ Tampa, Hillsborough County, FloridaMay 25, 2018 ■ Terracon Project No. H4185065

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REPORT SUMMARY

Topic 1 Overview Statement 2

ProjectDescription Addition of a service elevator to the existing convention center.

Double RingInfiltration (DRI)Test

Two DRI tests were performed at the requested locations (see Exploration Plan).The northernmost DRI revealed an infiltration rate of 4.8 in/hr and the southernmostinfiltration rate revealed an infiltration rate of 40.5 in/hr.

Seasonal HighGroundwaterTable

The hand augers encountered sandy soils and were terminated at 7 feet below theground surface. The groundwater table was encountered between 6.6 and 7 feetbelow the ground surface at the time of our borings. Based on our experience in thearea, and the depth to the groundwater table at the time of our testing, is our opinionthat the SHWT is at approximately 4 to 5 feet below the ground surface.

GeotechnicalCharacterization

It was proposed to perform a soil boring to 80 feet below the ground surface. It maybe of merit to first note that during our exploration at the sampling depth of 65 feet,approximately 40 foot of drilling rod was lost in the hole. We were unable to recoverthe rod, we grouted the 65-foot-deep hole with the lost rod and moved over slightlyand predrilled down to a depth of 65 feet to complete the sampling to 80 feet. Theresults of the two adjacent boreholes are contained in this single log.

The boring revealed sandy soils with varying amounts of clayey sands underlain bylimestone. The top of limestone formation was at the approximate depth of 18 feetbelow the ground surface. Competent (refusal) limestone conditions wereencountered starting at about a depth of 29 feet below the ground surface.

Earthwork

Considering the proposed elevator shaft, it is likely that the proposed structure willinclude a below grade aspect to the design. During our utility clearance we weremade aware of a 54-inch force main that runs parallel to the existing building in thevicinity of the proposed structure. We also encountered other minor buried utilitiesin the general area. Vegetation and buried utilities that will not be used should beremoved or relocated. Construction methods should consider any utilities that are toremain. The contractor should provide a plan for protection of those utilities.

AuxiliaryShallowFoundations(if applicable)

Shallow foundations can be used to support the auxiliary structures.Allowable bearing pressure = 2,500 psfExpected settlements: < 1 inch total, < ½ inch differential

Specialty DeepFoundationSystems

It is our understanding that the elevator shaft will be designed/constructedindependent of the existing structure. This will require a deep or specialty foundation.We recommend considering the following options: Helical Piles/Anchors, Micropilesor Driven Ductile Iron Piles.

Below GradeStructures The elevator shaft will likely contain some below grade components.

GeneralComments

This section contains important information about the limitations of this geotechnicalengineering report.

1. If the reader is reviewing this report as a pdf, the topics above can be used to access the appropriate sectionof the report by simply clicking on the topic itself.

2. This summary is for convenience only. It should be used in conjunction with the entire report for designpurposes.

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INTRODUCTION

Geotechnical Engineering ReportTampa Convention Center – Elevator Addition

333 South Franklin StreetTampa, Hillsborough County, Florida

Terracon Project No. H4185065May 25, 2018

INTRODUCTIONThis report presents the results of our subsurface exploration and geotechnical engineeringservices performed for the proposed elevator addition at the Tampa Convention Center to belocated at 333 South Franklin Street in Tampa, Hillsborough County, Florida. The purpose ofthese services is to provide information and geotechnical engineering recommendations relativeto:

■ Subsurface soil conditions ■ Foundation design options■ Groundwater conditions ■ Infiltration Results■ Site preparation and earthwork ■ Lateral earth pressures

The geotechnical engineering scope of services for this project included the advancement of onetest boring to a depth of approximately 80 feet below existing site grades.

Maps showing the site and boring locations are shown in the Site Location and ExplorationPlan sections, respectively.

SITE CONDITIONS

The following description of site conditions is derived from our site visit in association with thefield exploration and our review of publicly available geologic and topographic maps.

Item Description

Parcel Information

We understand that a service elevator is to be added to the existing TampaConvention Center along the north side.Latitude: 27.942053°, Longitude: -82.456511°See Site Location



ExistingImprovements The existing multi-story Tampa Convention Center is located on the site

Current GroundCover

The subject site is covered by pavement, landscaped areas and the existingconvention center.

Existing Topography

The site appears to be relatively flat. The Selmon Expressway isimmediately to the north of the site and the Hillsborough River is on the westand south sides of the site. The convention center “bridges” overChannelside Dr. South Franklin Ave. is located to the east.

PROJECT DESCRIPTION

Our initial understanding of the project was provided in our proposal and was discussed in theproject planning stage, our final understanding of the project conditions is as follows:

Item DescriptionBuilding Construction Addition of a service elevator to the existing convention center.Finished Floor Elevation Assumed to be within 1 to 2 feet of the existing elevation.Maximum Loads(assumed) Columns: 500 kips.

Grading/Slopes Assumed to be within 1 to 2 feet of existing grade.

Below Grade Structures It is our understanding that the proposed elevator may have a belowgrade component.

GEOTECHNICAL CHARACTERIZATION

Double Ring Infiltration (DRI) Test

Two double ring infiltration tests, designated DRI-1and DRI-2, were conducted as indicated onthe attached Test Location Plan. The results of the tests are included in the following table:

Test Location Area Function Vertical InfiltrationRate (in/hr)

InterpolatedHorizontal Rate

(in/hr)Porosity

DRI-1 Stormwater Mgmt 4.8 9.6 0.20

DRI-2 Stormwater Mgmt 40.5 60.8 0.20

The values presented in the table are actual un-factored measured values. We recommend thata factor of safety be applied to these values when designing the stormwater management systemfor this project.



Subsurface Profile

We have developed a general characterization of the subsurface soil and groundwater conditionsbased upon our review of the data and our understanding of the geologic setting and plannedconstruction. The following table provides our geotechnical characterization.

The geotechnical characterization forms the basis of our geotechnical calculations and evaluationof site preparation, foundation options and pavement options. As noted in General Comments,the characterization is based upon widely spaced exploration points across the site, and variationsare likely.

Stratum Approximate Depth toBottom of Stratum (feet) Material Description Consistency/Density

1 13 Poorly graded sand (SP) Loose2 18 Clayey Sand (SC) Loose

3 78.9 Weathered to UnweateredLimestone

--

It was proposed to perform a soil boring to the termination depth of 80 feet below the groundsurface. It may be of merit to note that during our exploration at the sampling depth of 65 feet,approximately 40 foot of drilling rod was lost in the original borehole. We were unable to recoverthe rod, we grouted the 65-foot-deep hole with the lost rod and moved over slightly and predrilleddown to a depth of 65 feet to complete the sampling to 80 feet. The results of the two adjacentboreholes are contained in this single log.

Conditions encountered at each boring location are indicated on the individual boring logs shownin the Exploration Results section and are attached to this report. Stratification boundaries onthe boring logs represent the approximate location of changes in native soil types; in situ, thetransition between materials may be gradual.

Groundwater Conditions

The boring was observed during drilling for the presence and level of groundwater. Groundwaterwas observed at a depth of 8.5 feet during our boring. However, the groundwater table wasencountered between 6.6 and 7 feet below the ground surface at the time of our hand augerborings (performed adjacent to the DRI tests). Based on our experience in the area, and the depthto the groundwater table at the time of our testing, is our opinion that the SHWT is at approximately4 to 5 feet below the ground surface.Groundwater level fluctuations occur due to seasonal variations in the amount of rainfall, runoffand other factors not evident at the time the borings were performed. Therefore, groundwaterlevels during construction or at other times in the life of the structure may be higher or lower than



the levels indicated on the boring logs. The possibility of groundwater level fluctuations shouldbe considered when developing the design and construction plans for the project.

GEOTECHNICAL OVERVIEW

The soil conditions at the subject site are suitable for the construction of the proposed serviceelevator. It is our understanding that the proposed elevator will likely not be structurally attached tothe existing building, therefore the proposed structure will require a specialty foundation anchoringit. We have evaluated the site conditions and it is our opinion that the following foundation optionsare feasible:

■ Helical Piles/Anchors■ Micropiles■ Driven Ductile Iron Piles

The General Comments section provides an understanding of the report limitations.

EARTHWORK

Site Preparation

Site preparation should begin with the removal of existing vegetation and pavement on the site.In addition, any utilities that will not be used in the new construction should be removed andtrenched backfilled and compacted per the specifications in this Earthwork section. Abandonedutilities that are not to be removed may be filled with an inert material, as long as the utilities donot affect the construction of the proposed structure. Tree removal should include roots down tofinger sized roots and topsoil should be removed from the construction areas. Wet or dry materialshould either be removed or moisture conditioned and re-compacted. The exposed surfaceshould then be proof-rolled to aid in locating loose or soft areas and to densify the exposed soils

Due to the proximity to the existing structure and possible issues with equipment accessibility,hand held compaction equipment may be used in conjunction with smaller lifts of fill placement (ifapplicable). The soils should be compacted sufficiently to obtain a minimum compaction asdefined in this report. Unstable soil should be removed or moisture conditioned and compactedin place prior to placing additional fill.Fill Material Types

Engineered fill should meet the following material property requirements:



Fill Type USCS Classification Acceptable Location for Placement

Structural 1SP, SP-SM or SP-SC (fines content< 12 percent, maximum particle size <2 inches, organic content < 5 percent)

All locations and elevations

1. Stratum 1 sands at this site appear to meet this criterion. Soils with fines content > 5 percent may retain moistureand be difficult to compact and achieve specified density and stability. These soils may need to be maintained dryof optimum to properly compact.

Fill Compaction Requirements

Structural fill should meet the following compaction requirements.

Item Structural Fill

Maximum Lift Thickness

12 inches or less in loose thickness when heavy vibratory compactionequipment is used. Maximum particle size should not exceed 2 inches in a12-inch lift.4 to 6 inches in loose thickness when hand-guided equipment (i.e. jumpingjack or plate compactor) is used. Maximum particle size should not exceed1 inch in a 4- to 6-inch lift.

Minimum CompactionRequirements

Beneath the building footprint should be compacted to at least 95 percent ofthe maximum dry density as determined by the modified Proctor Test(ASTM D-1557). The upper one foot of pavement subgrades should becompacted to at least 98 percent of the maximum dry density asdetermined by the modified Proctor Test (ASTM D-1557).

Water ContentRange As needed to achieve the minimum required density.

We recommend that engineered fill be tested for compaction during placement. Should the results of the in-placedensity tests indicate compaction limits have not been met, the area represented by the test should be reworked andretested as required until the compaction requirements are achieved.

Utility Trench Backfill

All trench excavations should be made with sufficient working space to permit construction includingbackfill placement and compaction. During utility excavation operations, the excavations couldencounter clayey soils within the excavations. These soils should be removed and replaced withsuitable material as previously defined when backfilling underground utility excavations.

Grading and Drainage

All grades must provide effective drainage away from the elevator during and after constructionand should be maintained throughout the life of the structure. Water retained next to the elevatorcan result in soil movements greater than those discussed in this report. Greater movements canresult in unacceptable differential floor slab and/or foundation movements, cracked slabs andwalls, and roof leaks. The roof should have gutters/drains with downspouts that discharge ontosplash blocks at a distance of at least 10 feet from the elevator.



Earthwork Construction Considerations

Trees or other vegetation whose root systems have the ability to remove excessive moisture fromthe subgrade and foundation soils should not be planted next to the structure. Trees andshrubbery should be kept away from the exterior edges of the foundation element a distance atleast equal to 1.5 times their expected mature height.

As a minimum, all temporary excavations should be sloped or braced as required by OccupationalHealth and Safety Administration (OSHA) regulations to provide stability and safe workingconditions. Temporary excavations will probably be required during grading operations. Thegrading contractor, by his contract, is usually responsible for designing and constructing stable,temporary excavations and should shore, slope or bench the sides of the excavations as required,to maintain stability of both the excavation sides and bottom. All excavations should comply withapplicable local, state and federal safety regulations, including the current OSHA Excavation andTrench Safety Standards.

Construction site safety is the sole responsibility of the contractor who controls the means,methods, and sequencing of construction operations. Under no circumstances shall theinformation provided herein be interpreted to mean Terracon is assuming responsibility forconstruction site safety, or the contractor's activities; such responsibility shall neither be impliednor inferred.

Construction Observation and Testing

The earthwork efforts should be monitored under the direction of Terracon. Monitoring shouldinclude documentation of adequate removal of vegetation and top soil, proof-rolling and mitigationof areas delineated by the proof-roll to require mitigation.

In areas of foundation excavations, the bearing subgrade should be evaluated under the directionof Terracon. In the event that unanticipated conditions are encountered, Terracon shouldrecommend mitigation options.

In addition to the documentation of the essential parameters necessary for construction, thecontinuation of Terracon into the construction phase of the project provides the continuity tomaintain Terracon’s evaluation of subsurface conditions, including assessing variations andassociated design changes.



AUXILIARY SHALLOW FOUNDATIONS

If the site has been prepared in accordance with the requirements noted in Earthwork, thefollowing design parameters are applicable for shallow foundations.

Design Parameters – Compressive Loads

Description Column Footing Wall FootingMonolithic Slab

Foundation 4

Net allowable bearing pressure 1 2,500 psf 2,500 psf 2,500 psf

Minimum width 30 inches 18 inches 12 inchesMinimum embedment below finishedgrade 2 18 inches 18 inches 12 inches

Compaction requirements 95 percent of the materials maximum modified Proctor drydensity for a depth of 12 inches below footing.

Minimum Testing Frequency

One field densitytest per footing fora minimum depthof 1 foot below thefooting subgrade.

One field densitytest per 50 linear

feet for a minimumdepth of 1 foot

below the footingsubgrade.

One field densitytest per 50 linear

feet for aminimum depth of1 foot below the

footing subgrade.

Approximate total settlement 3 <1 inch <1 inch <1 inch

Estimated differential settlement 3 <¾ inch betweencolumns

<¾ inch over 40feet

<¾ inch over 40feet

1. The recommended net allowable bearing pressure is the pressure in excess of the minimum surroundingoverburden pressure at the footing base elevation. Assumes any unsuitable fill or soft soils, if encountered,will be undercut and replaced with engineered fill.

2. For erosion protection.3. The foundation settlement will depend upon the variations within the subsurface soil profile, the structural

loading conditions, the embedment depth of the footings, the thickness of compacted fill, and the quality ofthe earthwork operations.

4. Turned-down portion of slab. For slab requirements see Section 4.5.1.

Foundation Construction Considerations

As noted in Earthwork, the footing excavations should be evaluated under the direction ofTerracon. The base of all foundation excavations should be free of water and loose soil, prior toplacing concrete. Concrete should be placed soon after excavating to reduce bearing soildisturbance. Footings should not be left open overnight. Care should be taken to prevent wettingor drying of the bearing materials during construction. Excessively wet or dry material or any



loose/disturbed material in the bottom of the footing excavations should beremoved/reconditioned before foundation concrete is placed.

If unsuitable bearing soils are encountered at the base of the planned footing excavation, theexcavation should be extended deeper to suitable soils, and the footings could bear directly onthese soils at the lower level or on lean concrete backfill placed in the excavationsas illustrated inthe sketch below.

Over-excavation for structural fill placement below footings should be conducted as shown below.The over-excavation should be backfilled up to the footing base elevation, with granular materialplaced, as recommended in the Earthwork section.

SPECIALTY DEEP FOUNDATION SYSTEMS

It is our understanding that the proposed elevator addition will not be structurally attached to theexisting Tampa Convention Center building. Therefore, the proposed elevator structure willrequire a deep foundation system to help support the loading conditions. At the time of this report,final loads had not been provided to us, below are foundation options we believe would be



appropriate taking into account the proposed structure and access limitations. It maybe of meritto note that construction methods should consider any utilities that are to remain. The contractorshould provide a plan for protection of those utilities. In addition, construction methods shouldalso consider protection to the existing structure.

Helical Piles/Anchors:

Helical piles are deep foundation underpinning elements constructed using steel shafts withhelical flights. There are several manufactures of the helical style foundations. The piles areadvanced to bearing depth by twisting them into the soil while monitoring torque to estimate thepile capacity. To properly estimate the torque conversion a detailed understanding of the soilconditions is necessary. Once the capacity is reached the top of the shafts can be connected tothe proposed structures shallow foundation. Some potential limitations for helical style piles couldbe related to whether it can penetrate the limestone to a sufficient depth to provide the requiredcapacity. Secondarily, the site is adjoining to the Hillsborough River which is likely brackish, sosome corrosion should be considered.

Micropiles:

Micropiles are deep foundation elements constructed using high-strength, small-diameter steelcasing and/or threaded bar. Capacities vary depending on the micropile size and subsurfaceprofile. The micropile casing generally has a diameter in the range of 3 to 10 inches. Typically,the casing is advanced to the design depth using a drilling technique. Reinforcing steel in the formof an all-thread bar is typically inserted into the micropile casing. High-strength cement grout isthen pumped into the casing. The casing may extend to the full depth or terminate above the bondzone with the reinforcing bar extending to the full depth.

Based on our boring logs the limestone is at about 18 feet below the ground surface and hardlimestone is encountered at about 28.5 feet below the ground surface. Frictional resistance thatcan be developed in this “hard” limestone will be on the order of 4 ksf, allowable. Assuming pileswith a diameter of 8 inches and a frictional skin resistance of 4 ksf, we determined that theapproximate resistance to the buoyant uplift forces per linear foot of pile would be 8 kips per linearfoot installed into the limestone. Potential corrosion is less likely for the micropiles as the groutwill provide cover for the steal.

Driven Ductile Iron Piles:

Driven Ductile Iron Pile is a driven pile system, utilizing high strength ductile cast iron pipe. Pilesections are connected together by a spigot and socket joint, which offers speed of connectiontogether with a high degree of stiffness. The piles are installed in a quick succession using anexcavator with a hydraulic hammer, to both pitch and drive each pile section.



The low mass of the individual pile sections means that piles can be driven with a light andversatile hydraulic excavator using a rapid stroke hydraulic hammer. This permits pile foundationsto be constructed where site conditions are difficult or space is limited. High bearing capacitiescan be obtained with a rapid-stroke hammer operated at very low impact energies. This results insmoother operations and almost vibration-free pile-driving in the immediate vicinity of existingstructures. Pile placement is possible to within 13 in. of existing structures, and the use ofexcavators means that inclined piles can be placed at almost any angle.

The use of a ductile iron pipe system results in relatively low material wastage. When a pileexperiences refusal, it is cut off at the foundation level and the cut off pile can become the leadsection for the next location.

The piles can range between 3 to 5 inches in diameter and can typically be designed for a 25-toncapacity, and be driven to refusal within the limestone formation. After driving, we recommendthat the piles be filled with grout. If tensile capacity is needed, a reinforcing bar can be installedafter the pile is driven.

Load Testing:

The finished piles will resist compressive, uplift/tension and lateral loads and when test ASTM D1143 (compressive), ASTM D 3689 (uplift/tension), and ASTM D 3966 (lateral) are used. Thetechnique has been used to support most types of structures. It may be prudent to perform loadtests on the controlling loading conditions for the subject structure.

SEISMIC CONSIDERATIONS

The Florida Building code indicates that seismic loading is not to be considered in the design ofstructures. Therefore, we do not consider seismic effects to be a concern at this site.

LATERAL EARTH PRESSURES

Design Parameters

Should it be necessary to construct retaining walls, we provide the following recommendationsfor their design and construction.



The lateral earth pressure recommendations herein are applicable to the design of rigid retainingwalls subject to slight rotation, such as cantilever, or gravity type concrete walls. Theserecommendations are not applicable to the design of modular block - geogrid reinforced backfillwalls. Recommendations covering these types of wall systems are beyond the scope of servicesfor this assignment. However, we would be pleased to develop recommendations for the designof such wall systems upon request.

Reinforced concrete walls with unbalanced backfill levels on opposite sides should be designedfor earth pressures at least equal to those indicated in the following table. Earth pressures will beinfluenced by structural design of the walls, conditions of wall restraint, methods of constructionand/or compaction and the strength of the materials being restrained. Two wall restraintconditions are shown. Active earth pressure is commonly used for design of free standingcantilever retaining walls and assumes wall movement. The "at rest" condition assumes no wallmovement. The recommended design lateral earth pressures do not include a factor of safetyand do not provide for possible hydrostatic pressure on the walls.

EARTHPRESSURE

CONDITIONS

COEFFICIENT FORBACKFILL TYPE

EQUIVALENTFLUID DENSITY

(pcf)

SURCHARGEPRESSURE, p1

(psf)

EARTHPRESSURE,

p2 (psf)Active (Ka) Granular - 0.29

Sandy silt/Silty Sand -0.36

3545

(0.29)S(0.36)S

(35)H(45)H

At-Rest (Ko) Granular - 0.46Sandy silt/Silty Sand -0.53

5565

(0.46)S(0.53)S

(55)H(65)H

Passive (Kp) Granular - 3.4Sandy silt/Silty Sand –2.8

400330

------

------

Applicable conditions to the above include:



n For active earth pressure, wall must rotate about base, with top lateral movements of about0.002 H to 0.004 H, where H is wall height

n For passive earth pressure to develop, wall must move horizontally to mobilize resistancen Uniform surcharge, where S is surcharge pressuren In-situ soil backfill weight a maximum of 120 pcfn Horizontal backfill, compacted between 95 and 98 percent of modified Proctor maximum dry

densityn Loading from heavy compaction equipment not includedn No hydrostatic pressures acting on walln No dynamic loadingn No safety factor included in soil parameters

Backfill placed against structures should consist of granular soils or low plasticity cohesive soils.Strata 1 soils satisfy this requirement. For the granular values to be valid, the granular backfillmust extend out from the base of the wall at an angle of at least 45 and 60 degrees from verticalfor the active and passive cases, respectively. To calculate the resistance to sliding, a value of0.35 should be used as the ultimate coefficient of friction between the footing and the underlyingsoi



GENERAL COMMENTS

Our analysis and opinions are based upon our understanding of the project, the geotechnicalconditions in the area, and the data obtained from our site exploration. Natural variations will occurbetween exploration point locations or due to the modifying effects of construction or weather.The nature and extent of such variations may not become evident until during or after construction.Terracon should be retained as the Geotechnical Engineer, where noted in the final report, toprovide observation and testing services during pertinent construction phases. If variationsappear, we can provide further evaluation and supplemental recommendations. If variations arenoted in the absence of our observation and testing services on-site, we should be immediatelynotified so that we can provide evaluation and supplemental recommendations.

Our scope of services does not include either specifically or by implication any environmental orbiological (e.g., mold, fungi, bacteria) assessment of the site or identification or prevention ofpollutants, hazardous materials or conditions. If the owner is concerned about the potential forsuch contamination or pollution, other studies should be undertaken.

Our services and any correspondence or collaboration through this system are intended for thesole benefit and exclusive use of our client for specific application to the project discussed andare accomplished in accordance with generally accepted geotechnical engineering practices withno third party beneficiaries intended. Any third party access to services or correspondence issolely for information purposes to support the services provided by Terracon to our client. Relianceupon the services and any work product is limited to our client, and is not intended for third parties.Any use or reliance of the provided information by third parties is done solely at their own risk. Nowarranties, either express or implied, are intended or made.

Site characteristics as provided are for design purposes and not to estimate excavation cost. Anyuse of our report in that regard is done at the sole risk of the excavating cost estimator as theremay be variations on the site that are not apparent in the data that could significantly impactexcavation cost. Any parties charged with estimating excavation costs should seek their own sitecharacterization for specific purposes to obtain the specific level of detail necessary for costing.Site safety, and cost estimating including, excavation support, and dewateringrequirements/design are the responsibility of others. If changes in the nature, design, or locationof the project are planned, our conclusions and recommendations shall not be considered validunless we review the changes and either verify or modify our conclusions in writing.

13

ATTACH MENTS

ATTACHMENTS



EXPLORATION AND TESTING PROCEDURES

Field Exploration

Number/Type of Test Boring Depth (feet) Planned Location

1 SPT 80 Proposed Elevator Location

2 DRI 2Proposed Elevator

Location/Assumed StormwaterManagement Area

Boring Layout and Elevations: Unless otherwise noted, Terracon personnel provided the boringlayout. Coordinates are obtained with a handheld GPS unit (estimated horizontal accuracy ofabout ±10 feet). If elevations and a more precise boring layout are desired, we recommendborings be surveyed following completion of fieldwork.

Subsurface Exploration Procedures: The SPT soil borings were drilled with a truck-mounted,rotary drilling rig equipped with an automatic hammer. A significantly greater efficiency isachieved with the automatic hammer compared to the conventional safety hammer operated witha cathead and rope. This higher efficiency has an appreciable effect on the SPT-N value. Theeffect of the automatic hammer's efficiency has been considered in the interpretation and analysisof the subsurface information for this report. The boreholes were advanced with a cutting headand stabilized with the use of bentonite (drillers’ mud). Soil samples were obtained by the splitspoon sampling procedure in general accordance with the Standard Penetration Test (SPT)procedure. In the split spoon sampling procedure, the number of blows required to advance thesampling spoon for each six-inch penetration by means of a 140-pound hammer with a free fallof 30 inches is recorded. the sum of the second and third six-inch increments is the standardpenetration resistance value (N). This value is used to estimate the in-situ relative density ofcohesionless soils and the consistency of cohesive soils. The sampling depths and the standardpenetration resistance values are shown on the boring logs.

The samples are placed in appropriate containers and taken to our soil laboratory for testing andclassification by a geotechnical engineer. Our exploration team prepares field boring logs as partof the drilling operations. These field logs include visual classifications of the materialsencountered during drilling and our interpretation of the subsurface conditions between samples.Final boring logs are prepared from the field logs. The final boring logs represent the geotechnicalengineer's interpretation of the field logs and include modifications based on observations andtests of the samples in our laboratory.

Double Ring Infiltration (DRI) Test: Two Double Ring Infiltration tests, DRI-1 and DRI-2, wereperformed within the proposed site. The DRI test procedure consisted of installing a 12-inchdiameter steel ring and a 24-inch diameter steel ring concentrically into the ground. Water was



then added to a desired head level of approximately 12 inches in both casings and held constant.The amount of infiltration observed in the inner ring versus time was then recorded. Thisprocedure was repeated for a total of 3 hours or until a stabilized infiltration rate was achieved.

Hand Augers: The hand auger boring procedure consisted of manually turning a 3-inch diameter,6-inch long sampler into the soil until it was full. The sampler was then retrieved and the soils inthe sampler were visually examined and classified. This procedure was repeated until the desiredtermination depth was achieved. Groundwater levels were measured in the boreholes at the timeof our field exploration to evaluate the depth to groundwater. These borings were then backfilledwith soil cuttings upon completion.

Laboratory Testing

During the field exploration, a portion of each recovered sample was placed into a jar andtransported to our laboratory for further visual observation. The soil samples were classified ingeneral accordance with the appended General Notes and the Unified Soil Classification Systembased on the material's texture and plasticity. The estimated group symbol for the Unified SoilClassification System is shown on the boring logs and a brief description of the Unified SoilClassification System.

Laboratory tests were not deemed necessary for this project.

SITE LOCA TION AND EXPLORATI ON PLANS

SITE LOCATION AND EXPLORATION PLANS

SITE LOCATIONTampa Convention Center - Service Elevator ■ Tampa, FLMay 25, 2018 ■ Terracon Project No. H4185065

TOPOGRAPHIC MAP IMAGE COURTESY OF THE U.S. GEOLOGICAL SURVEYQUADRANGLES INCLUDE: TAMPA, FL (1/1/1995).

DIAGRAM IS FOR GENERAL LOCATION ONLY, AND ISNOT INTENDED FOR CONSTRUCTION PURPOSES

SITE

EXPLORATION PLANTampa Convention Center - Service Elevator ■ Tampa, FLMay 25, 2018 ■ Terracon Project No. H4185065

DIAGRAM IS FOR GENERAL LOCATION ONLY, AND ISNOT INTENDED FOR CONSTRUCTION PURPOSES

AERIAL PHOTOGRAPHY PROVIDEDBY MICROSOFT BING MAPS

EXPLORATION RESUL TS

EXPLORATION RESULTS(DRI-1 and DRI-2)

Terracon Project No.: H4185065

PROJECT: Tampa Convention Center PROJECT LOCATION: Downtown Tampa, FLDATE OF TEST: 5/14/2018 TEST LOCATION: DRI-1DEPTH OF TEST: 2' DEPTH TO WATER TABLE: 7'

TEST RESULTS:TEST TIME INFLITRATION RATE (Inches/Hour)

0:10 min 6.00:10 min 4.1 Depth Description0:10 min 6.0 0-1.5' brown sand0:10 min 6.0 1.5'-7' light brown sand0:10 min 6.00:10 min 6.0

Average 1st Hour 5.70:15 min 4.70:15 min 4.50:15 min 5.00:15 min 5.3

Average 2nd Hour 4.90:30 min 4.90:30 min 4.8

Average 3rd Hour 4.8

INFILTRATION RATE: Inches Per Hour

Double Ring Infiltration Test Results

Soil Profile

4.8

Elapsed Time vs. Infiltration Rate Graph

Infil

trat

ion

Rate

(in/h

r)

Elapsed Time (mins)

Terracon Project No.: H4185065

PROJECT: Tampa Convention Center PROJECT LOCATION: Downtown Tampa, FLDATE OF TEST: 5/14/2018 TEST LOCATION: DRI-2DEPTH OF TEST: 2' DEPTH TO WATER TABLE: 6.6'

TEST RESULTS:TEST TIME INFLITRATION RATE (Inches/Hour)

0:10 min 28.50:10 min 36.0 Depth Description0:10 min 40.5 0-0.2' gray brown sand0:10 min 39.0 0.2'-3.5' brown/orange sand0:10 min 40.5 3.5'-6' lt. orange br. Sand0:10 min 42.0 6'-7' gray brown sand

Average 1st Hour 37.80:15 min 43.00:15 min 40.00:15 min 39.00:15 min 38.0

Average 2nd Hour 40.00:30 min 44.00:30 min 37.0

Average 3rd Hour 40.5

INFILTRATION RATE: Inches Per Hour40.5

Double Ring Infiltration Test Results

Soil Profile

Elapsed Time vs. Infiltration Rate Graph

Infil

trat

ion

Rate

(in/h

r)

Elapsed Time (mins)

EXPLORATION RESULTS(Boring B-1)

2-2-2-3N=4

2-3-3-3N=6

1-3-4N=7

9-11-5N=16

5-9-7N=16

50/1"

50/5"

7-27-50/5"

50/1"

50/2"

13.0

18.0

28.0

POORLY GRADED SAND (SP), grayish brown, hand auger performed to 6 feet

light brown

grayish brown

loose

CLAYEY SAND (SC), brown, loose

WEATHERED LIMESTONE, light gray

LIMESTONE, light gray

used 30 feet of 3 inch casing

GR

APH

ICLO

G

Hammer Type: AutomaticStratification lines are approximate. In-situ, the transition may be gradual.

THIS

BOR

ING

LOG

ISN

OT

VALI

DIF

SEPA

RAT

EDFR

OM

OR

IGIN

ALR

EPO

RT.

GEO

SMAR

TLO

G-N

OW

ELL

H41

8506

5TA

MPA

CO

NVE

NTI

ON

.GPJ

TER

RAC

ON

_DAT

ATEM

PLAT

E.G

DT

5/24

/18

WAT

ERLE

VEL

OBS

ERVA

TIO

NS

DEP

TH(F

t.)

5

10

15

20

25

30

35

40

45

50

SAM

PLE

TYPE

FIEL

DTE

STR

ESU

LTS

DEPTH

LOCATION See Exploration Plan

Latitude: 27.9431° Longitude: -82.4566°

Page 1 of 2

Advancement Method:Mud Rotary

Abandonment Method:Backfilled with bentonite chips upon completion

5463 W Waters Ave Ste 830Tampa, FL

Notes:

Project No.: H4185065

Drill Rig: CME 45

Boring Started: 05-14-2018

BORING LOG NO. B-1ASD, Inc.CLIENT:Tampa, FL

Driller: J. Coolidge

Boring Completed: 05-16-2018

PROJECT: Tampa Convention Center - ServiceElevator

See Exploration and Testing Procedures for adescription of field and laboratory procedures usedand additional data (If any).

See Supporting Information for explanation ofsymbols and abbreviations.

S. Franklin Street Tampa, FLSITE:

WT initially observed at 8.5'WATER LEVEL OBSERVATIONS

50/5"

15-23-25N=48

50/1"

50/2"

50/3"

50/1"78.9

LIMESTONE, light gray (continued)

Boring Terminated at 78.9 Feet

Note: It was proposed to perform a soil boring to the termination depth of 80 feet below the ground surface. Itmay be of merit to first note that during our exploration at the sampling depth of 65 feet, we lost approximately 40foot of drilling rod down the hole. Unable to recover the rod, we grouted the 65-foot-deep hole with the lost rodand moved over slightly and predrilled down to a depth of 65 feet to complete the sampling to 80 feet.

used 30 feet of 3 inch casing

GR

APH

ICLO

G

Hammer Type: AutomaticStratification lines are approximate. In-situ, the transition may be gradual.

THIS

BOR

ING

LOG

ISN

OT

VALI

DIF

SEPA

RAT

EDFR

OM

OR

IGIN

ALR

EPO

RT.

GEO

SMAR

TLO

G-N

OW

ELL

H41

8506

5TA

MPA

CO

NVE

NTI

ON

.GPJ

TER

RAC

ON

_DAT

ATEM

PLAT

E.G

DT

5/24

/18

WAT

ERLE

VEL

OBS

ERVA

TIO

NS

DEP

TH(F

t.)

55

60

65

70

75

SAM

PLE

TYPE

FIEL

DTE

STR

ESU

LTS

DEPTH

LOCATION See Exploration Plan

Latitude: 27.9431° Longitude: -82.4566°

Page 2 of 2

Advancement Method:Mud Rotary

Abandonment Method:Backfilled with bentonite chips upon completion

5463 W Waters Ave Ste 830Tampa, FL

Notes:

Project No.: H4185065

Drill Rig: CME 45

Boring Started: 05-14-2018

BORING LOG NO. B-1ASD, Inc.CLIENT:Tampa, FL

Driller: J. Coolidge

Boring Completed: 05-16-2018

PROJECT: Tampa Convention Center - ServiceElevator

See Exploration and Testing Procedures for adescription of field and laboratory procedures usedand additional data (If any).

See Supporting Information for explanation ofsymbols and abbreviations.

S. Franklin Street Tampa, FLSITE:

WT initially observed at 8.5'WATER LEVEL OBSERVATIONS

SUPPORTING INF ORMA TION

SUPPORTING INFORMATION

Exhibit: C-1

Unconfined CompressiveStrength Qu, (psf)

500 to 1,000

1,000 to 2,000

2,000 to 4,000

4,000 to 8,000

> 8,000

less than 500

Non-plasticLowMediumHigh

DESCRIPTION OF SYMBOLS AND ABBREVIATIONS

Hand Penetrometer

Torvane

Dynamic Cone Penetrometer

Photo-Ionization Detector

Organic Vapor AnalyzerSA

MP

LIN

G

WA

TE

R L

EV

EL

FIE

LD

TE

ST

S

(HP)

(T)

(DCP)

(PID)

(OVA)

GENERAL NOTES

Over 12 in. (300 mm)12 in. to 3 in. (300mm to 75mm)3 in. to #4 sieve (75mm to 4.75 mm)#4 to #200 sieve (4.75mm to 0.075mmPassing #200 sieve (0.075mm)

Particle Size

< 55 - 12> 12

Percent ofDry Weight

Descriptive Term(s)of other constituents

RELATIVE PROPORTIONS OF FINES

01 - 1011 - 30

> 30

Plasticity Index

Soil classification is based on the Unified Soil Classification System. Coarse Grained Soils have more than 50% of their dryweight retained on a #200 sieve; their principal descriptors are: boulders, cobbles, gravel or sand. Fine Grained Soils haveless than 50% of their dry weight retained on a #200 sieve; they are principally described as clays if they are plastic, andsilts if they are slightly plastic or non-plastic. Major constituents may be added as modifiers and minor constituents may beadded according to the relative proportions based on grain size. In addition to gradation, coarse-grained soils are definedon the basis of their in-place relative density and fine-grained soils on the basis of their consistency.

LOCATION AND ELEVATION NOTES

Percent ofDry Weight

Major Componentof Sample

TraceWithModifier

RELATIVE PROPORTIONS OF SAND AND GRAVEL GRAIN SIZE TERMINOLOGY

TraceWithModifier

DESCRIPTIVE SOIL CLASSIFICATION

BouldersCobblesGravelSandSilt or Clay

Descriptive Term(s)of other constituents

< 1515 - 29> 30

Term

PLASTICITY DESCRIPTION

Water levels indicated on the soil boringlogs are the levels measured in theborehole at the times indicated.Groundwater level variations will occurover time. In low permeability soils,accurate determination of groundwaterlevels is not possible with short termwater level observations.

Water Level Aftera Specified Period of Time

Water Level After aSpecified Period of Time

Water InitiallyEncountered

AugerCuttings Rock Core

GrabSample

NoRecovery

ShelbyTube

StandardPenetrationTest

Unless otherwise noted, Latitude and Longitude are approximately determined using a hand-held GPS device. The accuracyof such devices is variable. Surface elevation data annotated with +/- indicates that no actual topographical survey wasconducted to confirm the surface elevation. Instead, the surface elevation was approximately determined from topographicmaps of the area.

ST

RE

NG

TH

TE

RM

S

RELATIVE DENSITY OF COARSE-GRAINED SOILS

(More than 50% retained on No. 200 sieve.)Density determined by Standard Penetration Resistance

CONSISTENCY OF FINE-GRAINED SOILS(50% or more passing the No. 200 sieve.)

Consistency determined by laboratory shear strength testing, fieldvisual-manual procedures or standard penetration resistance

Descriptive Term(Consistency)

Very Soft

Soft

0 - 1

Safety HammerSPT N-Value(Blows/Ft.)

2 - 4

4 - 8

8 - 15

15 - 30

Automatic HammerSPT N-Value(Blows/Ft.)

1 - 3

3 - 6

6 - 12

12 - 24

> 24

Medium-Stiff

Stiff

Very Stiff

Hard

Descriptive Term(Density)

Very Loose

Loose

Medium Dense

Dense

Very Dense

Safety HammerSPT N-Value(Blows/Ft.)

0 - 3

4 - 9

10 - 29

30 - 50

> 50

Automatic HammerSPT N-Value(Blows/Ft.)

< 3

3 - 8

8 - 24

24 - 40

> 40

> 30

< 1

UNIFIED SOIL CLASSIFICATION SYSTEMTampa Convention Center – Elevator Addition ■ Tampa, Hillsborough County, FloridaMay 25, 2018 ■ Terracon Project No. H4185065

UNIFIED SOIL C LASSIFICATI ON SYSTEM

Criteria for Assigning Group Symbols and Group Names Using Laboratory Tests ASoil Classification

GroupSymbol Group Name B

Coarse-Grained Soils:More than 50% retainedon No. 200 sieve

Gravels:More than 50% ofcoarse fractionretained on No. 4 sieve

Clean Gravels:Less than 5% fines C

Cu ³ 4 and 1 £ Cc £ 3 E GW Well-graded gravel F

Cu < 4 and/or 1 > Cc > 3 E GP Poorly graded gravel F

Gravels with Fines:More than 12% fines C

Fines classify as ML or MH GM Silty gravel F, G, H

Fines classify as CL or CH GC Clayey gravel F, G, H

Sands:50% or more of coarsefraction passes No. 4sieve

Clean Sands:Less than 5% fines D

Cu ³ 6 and 1 £ Cc £ 3 E SW Well-graded sand I

Cu < 6 and/or 1 > Cc > 3 E SP Poorly graded sand I

Sands with Fines:More than 12% fines D

Fines classify as ML or MH SM Silty sand G, H, I

Fines classify as CL or CH SC Clayey sand G, H, I

Fine-Grained Soils:50% or more passes theNo. 200 sieve

Silts and Clays:Liquid limit less than 50

Inorganic:PI > 7 and plots on or above “A”line J

CL Lean clay K, L, M

PI < 4 or plots below “A” line J ML Silt K, L, M

Organic:Liquid limit - oven dried

< 0.75 OL Organic clay K, L, M, N

Liquid limit - not dried Organic silt K, L, M, O

Silts and Clays:Liquid limit 50 or more

Inorganic:PI plots on or above “A” line CH Fat clay K, L, M

PI plots below “A” line MH Elastic Silt K, L, M

Organic:Liquid limit - oven dried

< 0.75 OH Organic clay K, L, M, P

Liquid limit - not dried Organic silt K, L, M, Q

Highly organic soils: Primarily organic matter, dark in color, and organic odor PT PeatA Based on the material passing the 3-inch (75-mm) sieveB If field sample contained cobbles or boulders, or both, add “with cobbles

or boulders, or both” to group name.C Gravels with 5 to 12% fines require dual symbols: GW-GM well-graded

gravel with silt, GW-GC well-graded gravel with clay, GP-GM poorlygraded gravel with silt, GP-GC poorly graded gravel with clay.

D Sands with 5 to 12% fines require dual symbols: SW-SM well-gradedsand with silt, SW-SC well-graded sand with clay, SP-SM poorly gradedsand with silt, SP-SC poorly graded sand with clay

E Cu = D60/D10 Cc =6010

230

DxD

)(D

F If soil contains ³ 15% sand, add “with sand” to group name.G If fines classify as CL-ML, use dual symbol GC-GM, or SC-SM.

H If fines are organic, add “with organic fines” to group name.I If soil contains ³ 15% gravel, add “with gravel” to group name.J If Atterberg limits plot in shaded area, soil is a CL-ML, silty clay.K If soil contains 15 to 29% plus No. 200, add “with sand” or “with

gravel,” whichever is predominant.L If soil contains ³ 30% plus No. 200 predominantly sand, add

“sandy” to group name.MIf soil contains ³ 30% plus No. 200, predominantly gravel, add

“gravelly” to group name.NPI ³ 4 and plots on or above “A” line.OPI < 4 or plots below “A” line.P PI plots on or above “A” line.QPI plots below “A” line.

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