Geotechnical Engineering Report

Transcription

1 Mobile Offices and Future Service Center Range Road Eglin Air Force Base, Florida November 2, 2016 Project No. EA Prepared for: American States Utility Services, Inc. Prepared by: Terracon Consultants, Inc. Pensacola, Florida

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3 TABLE OF CONTENTS Page EXECUTIVE SUMMARY INTRODUCTION PROJECT INFORMATION Project Description Site Location and Description SUBSURFACE CONDITIONS Soil Data Typical Profile Groundwater RECOMMENDATIONS FOR DESIGN AND CONSTRUCTION Earthwork Site Preparation Fill Material Types Placement and Compaction Requirements Grading and Drainage Construction Considerations Foundations Design Recommendations Construction Considerations Seismic Considerations Floor Slab Design Recommendations Construction Considerations Pavements Subgrade Preparation Design Considerations Minimum Pavement Thickness Pavement Drainage Pavement Maintenance GENERAL COMMENTS APPENDIX A FIELD EXPLORATION Exhibit A-1 Site Location Map Exhibit A-2 Boring Location Plan Exhibit A-3 Field Exploration Description Exhibits A-4 to A-7 Borings Logs APPENDIX B LABORATORY TESTING Exhibit B-1 Laboratory Testing APPENDIX C SUPPORTING DOCUMENTS Exhibit C-1 Exhibit C-2 General Notes Unified Soil Classification Responsive Resourceful Reliable

4 Mobile Offices and Future Service Center Eglin Air Force Base, Florida EXECUTIVE SUMMARY A geotechnical investigation has been performed for the Mobile Offices and the Future Service Center to be constructed on Range Road at Eglin Air Force Base, Florida. The Mobile Offices will consist of two 24 feet by 60 feet units. The Future Service Center will be approximately 5700 square feet, one story structure, metal frame and brick veneer with a concrete slab on grade and parking/driveways. Two (2) soil borings were performed for the Mobile Offices and two (2) soil borings were performed for the Future Service Center to depths of approximately 15 feet below the existing ground surface. Based on the information obtained from our subsurface exploration, the following geotechnical considerations were identified: Soil borings B-1 and B-2 in the Mobile Office areas encountered medium dense to dense, sands to sands with silt. Soil borings B-3 and B-4 in the Future Service Center encountered medium dense to very dense sands to sands with silt. The shallow spread footings can be designed with an Allowable Soil Bearing Pressure of 2500 psf. The Future Service Center may be supported on shallow spread footings bearing on compacted native soil or newly placed engineered fill. Assuming proper site preparation and any necessary subgrade repair, total and differential settlement should be within anticipated ranges for the Mobile Offices and the Future Service Center. On-site native soils typically appear suitable for use as general engineered fill provided they meet the structural fill requirement. Significant moisture conditioning (e.g., wetting) of the on-site soils will likely be required during earthwork operations. The 2015 International Building Code (IBC), Table seismic site classification for this site is estimated as D. Close monitoring of the construction operations discussed herein will be critical in achieving the design subgrade support. We therefore recommend that Terracon be retained to monitor this portion of the work. Responsive Resourceful Reliable i

5 This summary should be used in conjunction with the entire report for design purposes. It should be recognized that details were not included or fully developed in this section, and the report must be read in its entirety for a comprehensive understanding of the items contained herein. The section titled GENERAL COMMENTS should be read for an understanding of the report limitations. Responsive Resourceful Reliable 2

6 GEOTECHNICAL ENGINEERING REPORT MOBILE OFFICES AND FUTURE SERVICE CENTER EGLIN AFB, FLORIDA Terracon Project No. EA November 2, INTRODUCTION A geotechnical investigation has been performed for the Mobile Offices and the Future Service Center to be constructed on Range Road at Eglin Air Force Base, Florida. The Mobile Offices will consist of two 24 feet by 60 feet units. The Future Service Center will be approximately 5,700 square feet, one story structure, metal frame and brick veneer with a concrete slab on grade with parking/driveways. Two (2) soil borings were performed for the Mobile Offices and two (2) soil borings were performed for the Future Service Center to depths of approximately 15 feet below the existing ground surface. Logs of the borings along with a vicinity map and boring location plan are included in Appendix A of this report. The purpose of these services is to provide information and geotechnical engineering recommendations relative to the proposed project: subsurface soil conditions foundation design and construction groundwater conditions earthwork seismic considerations pavement design and construction floor slab design and construction for the Future Service Center 2.0 PROJECT INFORMATION 2.1 Project Description Site Layout Structures ITEM DESCRIPTION See Appendix A, Exhibit A-2: Boring Location Plan The Mobile Offices foundations will consist of two 24 feet by 60 feet areas with tie down anchors and column foundations bearing on the ground surface. The tie down anchors will be designed by others. The column foundations will provide support for the mobile office units. The Future Service Center will be a one story structure, metal frame and brick veneer with a concrete slab on grade and parking/driveways. Responsive Resourceful Reliable 1

7 ITEM Finished Floor Elevation Maximum Loads Future Service Center Grading Fill slopes Below Grade Areas DESCRIPTION Not known at this time - Assumed to be within 2 feet of existing grades Building Columns: 50 kips (Assumed) Building Walls: 1.5 kip per linear foot (Assumed) Slabs: 150 psf (Assumed) Cut and fill thicknesses of less than 2 feet (Assumed) None None anticipated 2.2 Site Location and Description ITEM Location Existing improvements Current ground cover Existing topography DESCRIPTION The project site is located on Range Road west of Building 555 at Eglin Air Force Base, Florida. The site is a Vacant Parcel. The site is partially vegetated. Relatively flat. 3.0 SUBSURFACE CONDITIONS 3.1 Soil Data The Soil Survey of Okaloosa County, Florida, as prepared by the United States Department of Agriculture (USDA), Natural Resource Conservation Service (NRCS), dated 1984, identifies one major soil type at the subject site; Foxworth Sand with 0 to 5% slopes. The following table identifies the typical profile and constraints associated with the unit as identified by the Soil Survey. Land Form Typical Saturated Permeability Available Water Capacity Mean Annual Precipitation Depth to Water Table Drainage Class Foxworth Sand High to Very High Low 59 to to 72 Moderately Well Drained Responsive Resourceful Reliable 2

8 3.2 Typical Profile Based on the results of the borings, subsurface conditions can be generalized as follows: Description Approximate Depth to Bottom of Stratum (feet) Surface 0 to 1 1 Stratum 1 8 to 10 Material Encountered (USCS Classification) Topsoil (Silty Sand, Trace Organics and gravel) Sand to Sand with Silt (SP, SP-SM) Stratum Sand (SP) Consistency/Density N/A Loose to Very Dense (6 to 50) 2 Medium Dense to Dense (12 to 44) 1 Encountered in all 4 soil borings. 2 Range of Standard Penetration Test (SPT) resistance values or N-values, blows per foot. 3 Encountered to planned termination depths of 15 feet in all 4borings. Conditions encountered at each boring location are indicated on the individual boring logs. Stratification boundaries on the boring logs represent the approximate location of changes in soil types; in-situ, the transition between materials may be gradual. Details for each of the borings can be found on the boring logs in Appendix A. 3.3 Groundwater The boreholes were observed while drilling for the presence and level of groundwater. Groundwater was encountered at approximately 5 to 6 feet below the existing grade. This groundwater observation provides an indication of the groundwater conditions existing on the site at the time the borings were drilled. Based upon the soil survey, the seasonal high groundwater table is at 3.5 feet. It should be recognized that fluctuation of the groundwater level will occur due to seasonal variations in the amount of rainfall, runoff and other factors not evident at the time the borings were performed. Therefore, groundwater levels during construction or at other times in future may be higher than the levels indicated on the boring logs. The possibility of groundwater level fluctuations should be considered when developing the design and construction plans for the project. Responsive Resourceful Reliable 3

9 4.0 RECOMMENDATIONS FOR DESIGN AND CONSTRUCTION The geotechnical considerations presented herein are based on the available boring data, topographic information, and our experience with similar sites. Soil borings B-1 and B-2 in the Mobile Office areas encountered medium dense to dense, sands to sands with silt. Soil borings B-3 and B-4 in the Future Service Center encountered medium dense to very dense sands to sands with silt. The shallow spread footings for the Mobile Office can be designed with an Allowable Soil Bearing Pressure of 2,500 psf. The Future Service Center may also be supported on shallow spread footings bearing on compacted native soil or newly placed engineered fill. Design and construction recommendations for foundation systems and other earth connected phases of the project are outlined below. During construction, we highly recommend that Terracon be retained to evaluate the bearing material for the foundations, floor slab, and pavement subgrade soils. Subsurface conditions, as identified by the field and laboratory testing programs, have been reviewed and evaluated with respect to the proposed building plans known to us at this time. 4.1 Earthwork Site Preparation Prior to performing earthwork operations, vegetation, topsoil, and any otherwise unsuitable material should be completely removed from the site. We recommend subgrade observation be made prior to placement of fill. Excessively wet or dry material should be moisture conditioned and recompacted or removed and replaced (if necessary). The exposed subgrade should be proofrolled by the contractor and observed by Terracon. Proofrolling should be accomplished by using a vibratory drum roller with a minimum static weight of 20,000 pounds. A minimum of 10 overlapping passes should be made over all areas of the site. In addition, we recommend the subgrade be moisture conditioned and compacted to at least 95 percent of the material s maximum dry density (ASTM D1557). This proofrolling and compaction process will help densify the exposed sandy soils, provide a stable base for the compaction of new structural fill, and help delineate low density, loose, or disturbed areas that may exist below subgrade level. Upon completion of grading, care should be taken to maintain the subgrade moisture content prior to construction of grade supported slabs and pavements. Construction traffic over the Responsive Resourceful Reliable 4

10 completed subgrade should be avoided to the extent practical. The site should also be graded to prevent ponding of surface water on the prepared subgrades or in excavations. If the subgrade should become desiccated, saturated, or disturbed, the affected material should be removed or these materials should be scarified, moisture conditioned, and recompacted prior to slab and pavement construction Fill Material Types Engineered fill should meet the following material property requirements: Fill Type 1 USCS Classification Acceptable Location for Placement Off-Site Borrow SP, SP-SM All locations and elevations On-Site Soils 2 SP, SP-SM All locations and elevations 1. Controlled, compacted fill should consist of approved materials that are free of organic matter and debris. A sample of each material type should be submitted to the geotechnical engineer for evaluation. 2. On-site soils appear suitable for use as engineered fill; however, some sorting of deleterious materials may be required. Moisture conditioning of on-site soils will likely be required Placement and Compaction Requirements Fill Lift Thickness ITEM Minimum Compaction Requirements 1 Moisture Content DESCRIPTION 12-inches or less in loose thickness when heavy, self-propelled compaction equipment is used 4 to 6 inches in loose thickness when handguided equipment (i.e. jumping jack or plate compactor) is used 95% of the materials maximum modified Proctor dry density (ASTM D 1557) Within the range +/-3% of the optimum moisture content value as determined by the modified Proctor test at the time of placement and compaction We recommend that engineered fill be tested for moisture content and compaction during placement. Should the results of the in-place density tests indicate the specified moisture or compaction limits have not been met, the area represented by the test should be reworked and retested as required until the specified moisture and compaction requirements are achieved. 2. The moisture content in cohesionless soils with a minimal amount of fines (i.e., less than 7 percent) should be maintained to provide proper compaction while being low enough to allow for satisfactory compaction to be achieved without the cohesionless fill material pumping when proofrolled Grading and Drainage Final surrounding grades should be sloped away from the structures on all sides to prevent ponding of water. Gutters and downspouts that drain water a minimum of 5 feet beyond the Responsive Resourceful Reliable 5

11 footprint of the proposed structure are recommended. This can be accomplished through the use of splash-blocks, downspout extensions, and flexible pipes that are designed to attach to the end of the downspout. Flexible pipe should only be used if it is daylighted in such a manner that it gravity-drains collected water. Splash-blocks should also be considered below hose bibs and water spigots Construction Considerations Temporary excavations will probably be required during grading operations, utility installation, and foundation construction. The grading 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 with applicable local, state and federal safety regulations, including the current OSHA requirements. Terracon should be retained during the construction phase of the project to observe earthwork and to perform necessary tests and observations during subgrade preparation; proofrolling; placement and compaction of controlled compacted fills; backfilling of excavations into the completed subgrade, and just prior to construction of floor slabs. 4.2 Foundations The foundation system for the Mobile Office can be designed with an Allowable Soil Bearing Pressure of 2,500 psf. The proposed Future Service Center can be supported by shallow, spread footing foundation systems following successful preparation of the natural soil or engineered fill subgrade. Design recommendations for shallow foundations for the proposed structures are presented in the following sections Design Recommendations DESCRIPTION Column Footings Wall Footings Net allowable bearing pressure 1 : 2,500 psf 2,500 psf Minimum footing width 30 inches 18 inches Minimum embedment depth below finished grade 2 18 inches 18 inches Ultimate coefficient of sliding friction Minimum Compaction Requirements Minimum Testing Frequency 95 percent of the material s maximum Modified Proctor dry density (ASTM D 1557) One field density test per footing 95 percent of the material s maximum Modified Proctor dry density (ASTM D 1557) One field density test per 50 linear feet Responsive Resourceful Reliable 6

12 1. The recommended net allowable bearing pressure is the pressure in excess of the minimum surrounding overburden pressure at the footing base elevation. Assumes any loose sandy soils that cannot be densified in-place will be undercut and replaced with engineered fill. 2. Relative to lowest adjacent finished grade, typically exterior grade. 3. Sliding friction along the base of the footings will not develop where net uplift conditions exist Construction Considerations The bottom surface of all foundation excavations should be compacted with hand-held dynamic compaction equipment (i.e., jumping jack) prior to placement of forms and reinforcing steel. The base of all foundation excavations should be free of water and loose soil prior to placing concrete. Concrete should be placed soon after subgrade compaction to reduce bearing soil disturbance. Should the soils at bearing level become excessively dry, disturbed or saturated, the affected soil should be moisture conditioned and recompacted. It is recommended that the geotechnical engineer be retained to observe, test, and approve the soil foundation bearing materials. If loose sands that cannot be densified in place or otherwise unsuitable bearing soils are encountered in footing excavations, the excavations should be extended deeper to suitable soils and the footings could bear directly on these soils at the lower level or on lean concrete backfill placed in the excavation. The footings could also bear on properly compacted structural fill extending down to the suitable soil. Overexcavation for compacted backfill placement below footings should extend laterally beyond all edges of the footings at least 8 inches per foot of over-excavation depth below the design footing level. The overexcavation should then be backfilled up to the design footing level with in accordance with section 4.1 Earthwork. The over-excavation and backfill procedures are illustrated in the following figures. We recommend all excavations be sloped, shored, or braced to maintain stability. Excavations must be constructed in accordance with all local, state, and federal requirements including OSHA, as well as any other applicable codes. The individual contractor is responsible for designing and constructing stable, temporary excavations as required to maintain stability of both the sides and bottom of the excavation. Responsive Resourceful Reliable 7

13 4.3 Seismic Considerations Code Used Site Classification 2015 International Building Code (IBC) 1 D 2 1. In general accordance with the 2015 International Building Code, Table The 2015 International Building Code uses a site soil profile determination extending a depth of 100 feet for seismic site classification. The current scope does not include a 100 foot soil profile determination. An additional exploration to deeper depths could be performed to confirm the conditions below the current depth of exploration. Alternatively, a geophysical exploration could be utilized in order to attempt to justify a higher seismic site class. 4.4 Floor Slab Design Recommendations Floor slab support ITEM Modulus of subgrade reaction Aggregate base course/capillary break 2 DESCRIPTION Recompacted existing soils or compacted engineered fills pounds per square inch per inch (psi/in) for point loading conditions 4 inches of free draining granular material 1. Floor slabs should be structurally independent of any building footings or walls to reduce the possibility of floor slab cracking caused by differential movements between the slab and foundation. We recommend subgrades be maintained in a compacted, relatively moist condition until the aggregate base is placed. If the subgrade should become desiccated prior to construction of floor slabs, the affected material should be removed or the materials scarified, moistened, and recompacted. 2. The floor slab design should include a capillary break, comprised of at least 4 inches of freedraining, compacted, granular material. Free-draining granular material should have less than 7 percent fines (material passing the #200 sieve). Florida Limerock is not recommended as a capillary break, due to its moisture sensitivity. Where appropriate, saw-cut control joints should be placed in the slab to help control the location and extent of cracking. For additional recommendations refer to the ACI Design Manual. Where floor slabs are tied to perimeter walls or turn-down slabs to meet structural or other construction objectives, our experience indicates that any differential movement between the walls and slabs will likely be observed in adjacent slab expansion joints or floor slab cracks that occur beyond the length of the structural dowels. The structural engineer should account for Responsive Resourceful Reliable 8

14 this potential differential settlement through use of sufficient control joints, appropriate reinforcing or other means. The use of a vapor retarder should be considered beneath concrete slabs on grade that will be covered with wood, tile, carpet or other moisture sensitive or impervious coverings, or when the slab will support equipment sensitive to moisture. When conditions warrant the use of a vapor retarder, the slab designer should refer to ACI 302 and/or ACI 360 for procedures and cautions regarding the use and placement of a vapor retarder Construction Considerations On most project sites, the site grading is generally accomplished early in the construction phase. However as construction proceeds, the subgrade may be disturbed due to utility excavations, construction traffic, desiccation, rainfall, etc. As a result, the floor slab subgrade may not be suitable for placement of base material and concrete and corrective action will be required. We recommend the area underlying the floor slab be rough graded and then thoroughly proofrolled by the contractor and test probed by Terracon personnel prior to final grading and placement of base material. Particular attention should be paid to high traffic areas that were rutted and disturbed earlier and to areas where backfilled trenches are located. Areas where unsuitable conditions are located should be repaired by removing and replacing the affected material with properly compacted fill. All floor slab subgrade areas should be moisture conditioned and properly compacted to the recommendations in this report immediately prior to placement of the base material and concrete. 4.5 Pavements Subgrade Preparation On most project sites, the site grading is accomplished relatively early in the construction phase. Fills are placed and compacted in a uniform manner. However, as construction proceeds, excavations are made into these areas, rainfall and surface water saturates some areas, heavy traffic from concrete trucks and other delivery vehicles disturbs the subgrade and many surface irregularities are filled in with loose soils to improve trafficability temporarily. As a result, the pavement subgrades, initially prepared early in the project, should be carefully evaluated as the time for pavement construction approaches. We recommend the moisture content and density of the subgrade be evaluated and the pavement subgrades be proofrolled within two days prior to commencement of actual paving operations. Areas not in compliance with the required ranges of moisture or density should be moisture conditioned and recompacted. Particular attention should be paid to high traffic areas that were rutted and disturbed earlier and to areas where backfilled trenches are located. Areas where Responsive Resourceful Reliable 9

15 unsuitable conditions are located should be repaired by removing and replacing the materials with properly compacted structural fill. After proofrolling and repairing deep subgrade deficiencies, the entire subgrade should be scarified and developed as recommended in Section 4.1 Earthwork to provide a uniform subgrade for pavement construction. Areas that appear severely desiccated following site stripping may require further undercutting and moisture conditioning. If a significant precipitation event occurs after the evaluation or if the surface becomes disturbed, the subgrade should be reviewed by qualified personnel immediately prior to paving. The subgrade should be in its finished form at the time of the final review Design Considerations It is our understanding that traffic loads will be produced primarily by automobile traffic and delivery / garbage trucks. We have assumed either Portland Cement Concrete (PCC) or flexible asphalt concrete pavement will be considered for the pavements. Subgrade supporting concrete pavement should be free draining sand. The concrete should have a minimum compressive strength of 4,000 psi after 28 days of laboratory curing per ASTM C-31. All concrete pavements should have proper reinforcement, jointing, and sawcutting per American Concrete Institute (ACI) standards. All pavement construction should be in accordance with applicable sections of the FDOT Standard Specifications for Road and Bridge Construction. In order for a conventional flexible pavement to perform satisfactorily, the subgrade soils should have sufficient strength and stability to support construction traffic loading and design traffic loading. Our flexible pavement section recommendations are based on the following assumptions: The pavement surface should have a minimum ¼ inch per foot slope to promote proper surface drainage. The base course should be limerock or crushed concrete. Limerock base courses should be mined from a Florida Department of Transportation (FDOT) approved source. The base material should have a minimum LBR value of 100 and be compacted to a minimum of 98 percent of the maximum dry density as determined by ASTM D1557. The base course should be placed in lifts not to exceed 6 inches loose thickness. To verify thicknesses, after placement and compaction of the pavement courses, core the wearing surface to evaluate material thickness and composition at a minimum frequency of three cores per 40,000 square feet. All curbing should be full depth. Use of extruded curb sections which lie on top of asphalt surface courses can allow migration of water between the curb and asphalt surface, leading to pavement deterioration. Responsive Resourceful Reliable 10

16 Underdrains should be considered around all landscape islands and all other irrigated areas to control water intrusion into the pavement base. All surface water should be directed away from the edges of the pavement Minimum Pavement Thickness The following tables summarize the design inputs utilized for design of the flexible and rigid pavements. PAVEMENT DESIGN INPUT Input Parameter Asphalt Concrete Design Life 20 years 20 years Reliability 85% 85% Initial Serviceability Terminal Serviceability Standard Deviation Drainage Detailed vehicle loading information was not available at the time this report was prepared. However, we have assumed that pavement traffic will consist of only cars / light trucks in light duty areas and cars, light delivery trucks and garbage trucks in heavy duty areas. The following table presents our pavement thickness recommendations for light duty (Cars only - 30,000 E 18SALs) and heavy duty (50,000 E 18SALs) sections. Responsive Resourceful Reliable 11

17 Loading Type Minimum Pavement Section Thickness (inches) Asphalt Concrete Portland Cement Concrete 1 Aggregate Base Course or Crushed Concrete 2 Subbase Course (Stabilized Min. LBR = 30) Free Draining Subgrade Light Duty PCC N/A 12 (<30,000 ESALs, Cars AC Only) Heavy PCC N/A 12 Duty (<50,000 AC 2½ ESALs) Trash Container Pad 3 PCC N/A ,000 psi at 28 days, 4-inch maximum slump and 5 to 7 percent air entrained mix. PCC pavements are recommended for trash container pads and in any other areas subjected to heavy wheel loads and/or turning traffic (i.e., refueling areas). 2. Limerock Stabilized Base or Crushed Concrete. While not structurally required, a 4-inch (or greater) aggregate base is recommended below PCC pavements to help reduce potential slab curl, shrinkage cracking, and subgrade pumping through joints. 3. The trash container pad should be large enough to support the container and the tipping axle of the collection truck. We recommend that concrete pavement be utilized in entrance and exit sections, dumpster pads, or other areas where extensive wheel maneuvering is expected. The recommended pavement designs are subject to successful completion of site and subgrade preparation and fill placement as recommended in this report. The upper 1-foot of pavement subgrade soils (also identified as stabilized subbase) should be stabilized to a minimum Limerock Bearing Ratio (LBR; Florida Method of Test Designation FM 5-515) value of 30 if they do not already meet this criterion, or replaced with new compacted fill that meets the minimum LBR value. Although LBR testing has not been performed, our experience with similar soils indicates that the near surficial sands encountered in the soil borings are unlikely to meet this requirement. If stabilizing admixtures are needed, they should consist of coarse granular materials such as crushed Limerock, recycled concrete, shell or Limerock screenings. Silty sand or clayey sand admixtures should be avoided due to their tendency to retain moisture. Responsive Resourceful Reliable 12

18 Adequate reinforcement and number of longitudinal and transverse control joints should be placed in the rigid pavement in accordance with ACI requirements. The joints should be sealed as soon as possible (in accordance with sealant manufactures instructions) to minimize infiltration of water into the soil. Pavement materials should conform to current FDOT Standard Specifications for Highway Construction. Based on the anticipated traffic volumes we recommend SP-9.5 or SP-12.5 mixes be used. Asphaltic cement concrete should be an approved FDOT mix. Pavement thickness can also be determined using AASHTO, Asphalt Institute and/or other methods if specific wheel loads, axle configurations, frequencies, and desired pavement life are provided. Terracon can provide thickness recommendations for pavements subjected to loads other than personal vehicle and occasional delivery and trash removal truck traffic if this information is provided. Where practical, we recommend early-entry cutting of crack-control joints in Portland cement concrete pavements. Cutting of the concrete in its green state typically reduces the potential for micro-cracking of the pavements prior to the crack control joints being formed, compared to cutting the joints after the concrete has fully set. Micro-cracking of pavements may lead to crack formation in locations other than the sawed joints, and/or reduction of fatigue life of the pavement. Terracon has observed dishing in some parking lots surfaced with ACC. Dishing is usually observed in frequently-used parking stalls (such as near the front of buildings), and occurs under the wheel footprint in these stalls. The use of higher-grade asphaltic cement, or surfacing these areas with PCC, should be considered. The dishing is exacerbated by factors such as irrigated islands or planter areas, and sheet surface drainage to the front of structures Pavement Drainage Pavements should be sloped to provide rapid drainage of surface water. Water allowed to pond on or adjacent to the pavements could saturate the subgrade and contribute to premature pavement deterioration. In addition, the pavement subgrade should be graded to provide positive drainage within the granular base section. Appropriate sub-drainage or connection to a suitable daylight outlet should be provided to remove water from the granular subbase Pavement Maintenance The pavement sections provided in this report represent minimum recommended thicknesses and, as such, periodic maintenance should be anticipated. Therefore preventive maintenance should be planned and provided for through an on-going pavement management program. Preventive maintenance activities are intended to slow the rate of pavement deterioration, and to preserve the pavement investment. Preventive maintenance consists of both localized maintenance (e.g., crack and joint sealing and patching) and global maintenance (e.g., surface Responsive Resourceful Reliable 13

19 sealing). Preventive maintenance is usually the first priority when implementing a planned pavement maintenance program and provides the highest return on investment for pavements. Prior to implementing any maintenance, additional engineering observation is recommended to determine the type and extent of preventive maintenance. Even with periodic maintenance, some movements and related cracking may still occur and repairs may be required. Pavement performance is affected by its surroundings. In addition to providing preventive maintenance, the civil engineer should consider the following recommendations in the design and layout of pavements: Final grade adjacent to parking lots and drives should slope down from pavement edges at a minimum 2%; The subgrade and the pavement surface should have a minimum ¼ inch per foot slope to promote proper surface drainage; Install pavement drainage surrounding areas anticipated for frequent wetting; Install joint sealant and seal cracks immediately; Seal all landscaped areas in or adjacent to pavements to reduce moisture migration to subgrade soils. 5.0 GENERAL COMMENTS Terracon should be retained to review the final design plans and specifications so comments can be made regarding interpretation and implementation of our geotechnical recommendations in the design and specifications. Terracon also should be retained to provide observation and testing services during grading, excavation, foundation construction and other earth-related construction phases of the project. The analysis and recommendations presented in this report are based upon the data obtained from the borings performed at the indicated locations and from other information discussed in this report. This report does not reflect variations that may occur between borings, across the site, 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. If variations appear, we should be immediately notified so that further evaluation and supplemental recommendations can be provided. The scope of services for this project does not include either specifically or by implication any environmental or biological (e.g., mold, fungi, bacteria) assessment of the site or identification or prevention of pollutants, hazardous materials or conditions. If the owner is concerned about the potential for such contamination or pollution, other studies should be undertaken. This report has been prepared for the exclusive use of our client for specific application to the project discussed and has been prepared in accordance with generally accepted geotechnical Responsive Resourceful Reliable 14

20 engineering practices. No warranties, either express or implied, are intended or made. Site safety, excavation support, and dewatering requirements are the responsibility of others. In the event that changes in the nature, design, or location of the project as outlined in this report are planned, the conclusions and recommendations contained in this report shall not be considered valid unless Terracon reviews the changes and either verifies or modifies the conclusions of this report in writing. Responsive Resourceful Reliable 15

21 APPENDIX A FIELD EXPLORATION

22 DIAGRAM IS FOR GENERAL LOCATION ONLY, AND IS NOT INTENDED FOR CONSTRUCTION PURPOSES Drawn by: PROJECT:EA DPR Project Manager: DPR Scale: N.T.S. Checked by: Approved by: JBK File Name: JBK Date: 10/31/ North Davis Highway Pensacola, Florida PH. (850) FAX. (850) SITE LOCATION MAP MOBILE OFFICES AND FUTURE SERVICE CENTER RANGE ROAD EGLIN AIR FORCE BASE, FLORIDA Exhibit A-1

23 SW-1 SW-2 DIAGRAM IS FOR GENERAL LOCATION ONLY, AND IS NOT INTENDED FOR CONSTRUCTION PURPOSES Project Manager: DPR Drawn by: DPR Checked by: JBK Approved by: JBK Project No. EA Scale: N.T.S. File Name: EA Date: 10/31/ North Davis Highway Pensacola, Florida PH. (850) FAX. (850) BORING LOCATION PLAN Exhibit MOBILE OFFICES AND FUTURE SERVICE CENTER RANGE ROAD EGLIN AIR FORCE BASE, FLORIDA A-2

24 Field Exploration Description Terracon s field exploration consisted of performing four (4) borings at the project site. The borings were extended to depths of about 15 feet below the existing site grades. The boring locations were provided by the client and Terracon used GPS coordinates to locate the borings. The approximate boring locations are indicated on the attached Boring Location Plan. The ground surface elevations indicated on the boring logs are also approximate (rounded to the nearest ½ foot), and were interpolated off the supplied topographic information provided by GPI Southeast, Inc. The boring locations and elevations should be considered accurate only to the degree implied by the means and methods used to define them. The borings were drilled with a truck-mounted, rotary drilling rig using continuous flight, hollowand solid-stemmed augers to advance the boreholes. Samples were obtained using split-barrel sampling procedures. In the split-barrel sampling procedure, a standard 2-inch O.D. split-barrel sampling spoon is driven into the ground with a 140-pound hammer falling a distance of 30 inches. The number of blows required to advance the sampling spoon the last 12 inches of a normal 18-inch penetration is recorded as the standard penetration resistance value. These values are indicated on the boring logs at the corresponding depths of occurrence. The samples were sealed and returned to the laboratory for testing and classification. Field logs of the borings were prepared by the drill crew. Each log included visual classification of the materials encountered during drilling as well as the driller's interpretation of the subsurface conditions between samples. The boring logs included with this report represent an interpretation of the field logs by a geotechnical engineer and include modifications based on laboratory observation and tests on select samples. Exhibit A-3

25 PROJECT: Bearing Capacities for Mobile Offices and Future Service Center SITE: Range Road Eglin Air Force Base, Florida GRAPHIC LOG LOCATION See Exhibit A-2 DEPTH SAND (SP), with roots, gray, Topsoil 6" 0.5 SAND WITH SILT (SP-SM), brown, medium dense BORING LOG NO. B-1 American States Utility Services CLIENT: Fayetteville, NC DEPTH (Ft.) WATER LEVEL OBSERVATIONS SAMPLE TYPE FIELD TEST RESULTS N=23 Page 1 of 1 WATER CONTENT (%) 3 PERCENT FINES THIS BORING LOG IS NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GEO SMART LOG-NO WELL EA BEARING CAPACITY EGLIN AFB.GPJ TERRACON2015.GDT 10/31/ SAND (SP), gray, loose SAND WITH SILT (SP-SM), brown, loose to medium dense 10.0 SAND (SP), brown, dense 15.0 Boring Terminated at 15 Feet Stratification lines are approximate. In-situ, the transition may be gradual. Advancement Method: Mud Rotary Abandonment Method: Borings backfilled with soil cuttings upon completion. WATER LEVEL OBSERVATIONS Groundwater observed at 5' See Exhibit A-3 for description of field procedures. See Appendix B for description of laboratory procedures and additional data (if any). See Appendix C for explanation of symbols and abbreviations N Davis Hwy Pensacola, FL Hammer Type: Rope and Cathead Notes: Boring Started: 10/14/2016 Drill Rig: Trailer Mounted Project No.: EA N= N= N= N= N=44 Driller: SR Boring Completed: 10/14/2016 Exhibit: A-4

26 PROJECT: Bearing Capacities for Mobile Offices and Future Service Center SITE: Range Road Eglin Air Force Base, Florida GRAPHIC LOG LOCATION See Exhibit A-2 DEPTH FILL - SILTY SAND (SM), with gravel, 12" BORING LOG NO. B-2 American States Utility Services CLIENT: Fayetteville, NC DEPTH (Ft.) WATER LEVEL OBSERVATIONS SAMPLE TYPE FIELD TEST RESULTS Page 1 of 1 WATER CONTENT (%) PERCENT FINES 1.0 SAND WITH SILT (SP-SM), brown, dense N=35 THIS BORING LOG IS NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GEO SMART LOG-NO WELL EA BEARING CAPACITY EGLIN AFB.GPJ TERRACON2015.GDT 10/31/ SAND WITH SILT (SP-SM), brown, loose to medium dense 10.0 SAND (SP), brown, dense 15.0 Boring Terminated at 15 Feet Stratification lines are approximate. In-situ, the transition may be gradual. Advancement Method: Mud Rotary Abandonment Method: Borings backfilled with soil cuttings upon completion. WATER LEVEL OBSERVATIONS Groundwater observed at 5' See Exhibit A-3 for description of field procedures. See Appendix B for description of laboratory procedures and additional data (if any). See Appendix C for explanation of symbols and abbreviations N Davis Hwy Pensacola, FL Hammer Type: Rope and Cathead Notes: Boring Started: 10/14/2016 Drill Rig: Trailer Mounted Project No.: EA N= N= N= N= N=30 Driller: SR Boring Completed: 10/14/2016 Exhibit: A-5

27 PROJECT: Bearing Capacities for Mobile Offices and Future Service Center SITE: Range Road Eglin Air Force Base, Florida GRAPHIC LOG LOCATION See Exhibit A-2 DEPTH FILL - SAND (SP), with gravel, 6" 0.5 SAND (SP), brown to gray, dense to very dense BORING LOG NO. B-3 American States Utility Services CLIENT: Fayetteville, NC DEPTH (Ft.) WATER LEVEL OBSERVATIONS SAMPLE TYPE FIELD TEST RESULTS N=45 Page 1 of 1 WATER CONTENT (%) 4 PERCENT FINES THIS BORING LOG IS NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GEO SMART LOG-NO WELL EA BEARING CAPACITY EGLIN AFB.GPJ TERRACON2015.GDT 10/31/ SAND WITH SILT (SP-SM), brown, medium dense SAND (SP), brown to tan, dense 15.0 Boring Terminated at 15 Feet Stratification lines are approximate. In-situ, the transition may be gradual. Advancement Method: Mud Rotary Abandonment Method: Borings backfilled with soil cuttings upon completion. WATER LEVEL OBSERVATIONS Groundwater observed at 6' See Exhibit A-3 for description of field procedures. See Appendix B for description of laboratory procedures and additional data (if any). See Appendix C for explanation of symbols and abbreviations N Davis Hwy Pensacola, FL Hammer Type: Rope and Cathead Notes: Boring Started: 10/14/2016 Drill Rig: Trailer Mounted Project No.: EA N= N= N= N= N=36 Driller: SR Boring Completed: 10/14/2016 Exhibit: A-6

28 PROJECT: Bearing Capacities for Mobile Offices and Future Service Center SITE: Range Road Eglin Air Force Base, Florida GRAPHIC LOG LOCATION See Exhibit A-2 DEPTH 0.1 SAND WITH SILT (SP-SM), with roots, brown, Topsoil 2" SAND WITH SILT (SP-SM), orange to gray, medium dense BORING LOG NO. B-4 American States Utility Services CLIENT: Fayetteville, NC DEPTH (Ft.) WATER LEVEL OBSERVATIONS SAMPLE TYPE FIELD TEST RESULTS N=22 Page 1 of 1 WATER CONTENT (%) 4 PERCENT FINES 7 THIS BORING LOG IS NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GEO SMART LOG-NO WELL EA BEARING CAPACITY EGLIN AFB.GPJ TERRACON2015.GDT 10/31/ SAND WITH SILT (SP-SM), tan to brown, medium dense 10.0 SAND (SP), brown, dense 15.0 Boring Terminated at 15 Feet Stratification lines are approximate. In-situ, the transition may be gradual. Advancement Method: Mud Rotary Abandonment Method: Borings backfilled with soil cuttings upon completion. WATER LEVEL OBSERVATIONS Groundwater observed at 5' See Exhibit A-3 for description of field procedures. See Appendix B for description of laboratory procedures and additional data (if any). See Appendix C for explanation of symbols and abbreviations N Davis Hwy Pensacola, FL Hammer Type: Rope and Cathead Notes: Boring Started: 10/14/2016 Drill Rig: Trailer Mounted Project No.: EA N= N= N= N= N=41 Driller: SR Boring Completed: 10/14/2016 Exhibit: A-7

29 APPENDIX B LABORATORY TESTING

30 Laboratory Testing Select soil samples were tested in the laboratory to measure their natural water contents. In addition, percent fines tests were performed on select samples. The results of the laboratory tests are shown on the boring logs, adjacent to the soil profiles, at their corresponding sample depths and/or as attachments to this exhibit. As a part of the laboratory testing program, the soil samples were classified in the laboratory based on visual observation, texture, plasticity, and the limited laboratory testing described above. Portions of the recovered samples will be retained for at least 1 month in case additional testing is requested. The soil descriptions presented on the boring logs for native soils are in accordance with our enclosed General Notes and Unified Soil Classification System (USCS). The estimated group symbol for the USCS is also shown on the boring logs, and a brief description of the Unified System is attached to this report. Moisture Content In order to determine the moisture content of a selected sample, the test specimen was dried in an oven to constant mass in general accordance with ASTM D2216. The moisture content was then calculated using the mass of the water and the mass of the dry specimen. The moisture content is used to express the phase relationship of air, water and solid in a given volume of material. Per Cent Finer than the #200 Sieve Select soil samples were analyzed for fines content by measuring the percentage, by weight of dry soil sample, passing a U.S. standard No. 200 sieve in general accordance with ASTM D1140. These test results were used to help classifying of the tested soils in accordance with the Unified Soil Classification System (USCS/ASTM D2487). Exhibit B-1

31 APPENDIX C SUPPORTING DOCUMENTS

32 DESCRIPTION OF SYMBOLS AND ABBREVIATIONS GENERAL NOTES Water Initially Encountered (HP) Hand Penetrometer Auger Split Spoon Water Level After a Specified Period of Time (T) Torvane SAMPLING Shelby Tube Ring Sampler Grab Sample Macro Core Rock Core No Recovery WATER LEVEL Water Level After a Specified Period of Time Water levels indicated on the soil boring logs are the levels measured in the borehole at the times indicated. Groundwater level variations will occur over time. In low permeability soils, accurate determination of groundwater levels is not possible with short term water level observations. FIELD TESTS (b/f) (PID) (OVA) Standard Penetration Test (blows per foot) Photo-Ionization Detector Organic Vapor Analyzer DESCRIPTIVE SOIL CLASSIFICATION Soil classification is based on the Unified Soil Classification System. Coarse Grained Soils have more than 50% of their dry weight retained on a #200 sieve; their principal descriptors are: boulders, cobbles, gravel or sand. Fine Grained Soils have less than 50% of their dry weight retained on a #200 sieve; they are principally described as clays if they are plastic, and silts if they are slightly plastic or non-plastic. Major constituents may be added as modifiers and minor constituents may be added according to the relative proportions based on grain size. In addition to gradation, coarse-grained soils are defined on the basis of their in-place relative density and fine-grained soils on the basis of their consistency. LOCATION AND ELEVATION NOTES Unless otherwise noted, Latitude and Longitude are approximately determined using a hand-held GPS device. The accuracy of such devices is variable. Surface elevation data annotated with +/- indicates that no actual topographical survey was conducted to confirm the surface elevation. Instead, the surface elevation was approximately determined from topographic maps of the area. RELATIVE DENSITY OF COARSE-GRAINED SOILS (More than 50% retained on No. 200 sieve.) Density determined by Standard Penetration Resistance Includes gravels, sands and silts. CONSISTENCY OF FINE-GRAINED SOILS (50% or more passing the No. 200 sieve.) Consistency determined by laboratory shear strength testing, field visual-manual procedures or standard penetration resistance STRENGTH TERMS Descriptive Term (Density) Loose Medium Dense Dense Standard Penetration or N-Value Blows/Ft. Ring Sampler Blows/Ft. Descriptive Term (Consistency) Very Loose Very Soft Standard Penetration or N-Value Blows/Ft. Ring Sampler Blows/Ft. 0-1 < Soft 500 to 1, Stiff Unconfined Compressive Strength, Qu, psf less than 500 Medium-Stiff 1,000 to 2, ,000 to 4, Very Dense > 50 > _ 99 Very Stiff 4,000 to 8, Hard > 8,000 > 30 > 42 RELATIVE PROPORTIONS OF SAND AND GRAVEL Descriptive Term(s) of other constituents Percent of Dry Weight Major Component of Sample GRAIN SIZE TERMINOLOGY Particle Size Trace With Modifier < > 30 Boulders Cobbles Gravel Sand Silt or Clay 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 0.075mm Passing #200 sieve (0.075mm) RELATIVE PROPORTIONS OF FINES Descriptive Term(s) of other constituents Trace With Modifier Percent of Dry Weight < > 12 Term Non-plastic Low Medium High PLASTICITY DESCRIPTION Plasticity Index > 30 Exhibit C-1