ITEM NO. 1: NEW MAINTENANCE BAY TECHNICAL SPECIFICATIONS, SECTION :

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1 ADDENDUM NO. 3 Project: FMS #8 LIFE CYCLES UPGRADE AND NEW MAINTENANCE BAY Florida National Guard Lake City, Florida September 10, 2018 This Addendum forms a part of the contract documents and modifies the drawings and specifications dated August 1, 2018, as noted below. Acknowledge receipt of the Addendum in the space provided on the proposal form. Failure to do so may subject Bidder to disqualification. ITEM NO. 1: NEW MAINTENANCE BAY TECHNICAL SPECIFICATIONS, SECTION : ADD: See attached Subsurface Soil Exploitation and Geotechnical Engineering Evaluation for the Lake City Armory Maintenance Building. END OF ADDENDUM NO. 3 Attached: Subsurface Soil Exploitation and Geotechnical Engineering Evaluation for the Lake City Armory Maintenance Building

2 Subsurface Soil Exploration and Geotechnical Engineering Evaluation Lake City Armory Maintenance Building 490 Northwest Lake Jeffrey Road Lake City, Columbia County, Florida Ardaman & Associates, Inc. OFFICES Orlando 8008 S. Orange Avenue, Orlando, Florida Phone (407) Alexandria 3609 Mac Lee Drive, Alexandria, Louisiana Phone (318) Bartow 1525 Centennial Drive, Bartow, Florida Phone (863) Baton Rouge 316 Highlandia Drive, Baton Rouge, Louisiana Phone (225) Cocoa 1300 N. Cocoa Blvd., Cocoa, Florida Phone (321) Fort Myers 9970 Bavaria Road, Fort Myers, Florida Phone (239) Miami 2608 W. 84 th Street, Hialeah, Florida Phone (305) Monroe 1122 Hayes Street, West Monroe, Louisiana Phone (318) New Orleans 1305 Distributors Row, Suite I, Jefferson, Louisiana Phone (504) Port St. Lucie 460 Concourse Place NW, Unit 1, Port St. Lucie, Florida Phone (772) Sarasota 78 Sarasota Center Blvd., Sarasota, Florida Phone (941) Shreveport 7222 Greenwood Road, Shreveport, Louisiana Phone (318) Tallahassee 3175 West Tharpe Street, Tallahassee, Florida Phone (850) Tampa 3925 Coconut Palm Drive, Suite 115, Tampa, Florida Phone (813) West Palm Beach 2200 North Florida Mango Road, Suite 101, West Palm Beach, Florida Phone (561) MEMBERS: A.S.F.E. American Concrete Institute ASTM International Florida Institute of Consulting Engineers

3 Ardaman & Associates, Inc. Geotechnical, Environmental and Materials Consultants January 3, 2018 File No John Knox Road, Suite 105 Tallahassee, FL Attention: Subject: Mr. Iain Harnden, LEED AP Subsurface Soil Exploration and Geotechnical Engineering Evaluation Maintenance Building Renovation Florida Army National Guard 490 N.W. Lake Jeffrey Road Lake City, Columbia County, Florida Dear Mr. Harnden: As requested and authorized, we have completed a shallow subsurface soil exploration for the subject project. The purposes of performing this exploration were to evaluate the general subsurface conditions and to provide recommendations for site preparation and foundation support for the proposed structure, retaining wall and pavements. This report documents our findings and presents our engineering recommendations. SITE LOCATION AND DESCRIPTION The project site is located at 490 Northwest Lake Jeffrey Road in Lake City, Florida. The project location is located on the east end of the subject stie, near the intersection of N.W. Lake Jeffery Road and N.W. Ashley Street at the pale yellow maintenance building. The project site location is shown on figure 1. At the time of our exploration, the site was developed with an existing maintenance building located in place of the proposed maintenance building. The project location is surrounded by buildings, concrete pavement, and grassy areas with some trees. PROPOSED CONSTRUCTION AND GRADING It is our understanding that the proposed development includes the demolition of the existing maintenance building and the construction of a one story, 2,075 square foot building measuring 83-feet long and 25-feet long with a slab on grade. No additional changes will be made to the subject site. For the purposes of our analysis, we have assumed the maximum loading conditions for the structure to be on the order of 3 kips per linear foot for wall foundations and 100 kips for individual column foundations. Floor loads are assumed to be less than 100 pounds per square foot. Because the building will be located within the footprint of the existing building, we have assumed that less than one (1) foot of fill is required to reach final elevation for the building addition and the parking and drive ways will approximately match existing grades West Tharpe Street, Tallahassee, FL Phone (850) Fax (850) Offices in: Bartow, Cocoa, Fort Lauderdale, Fort Myers, Miami Orlando, Port Charlotte, Port St. Lucie, Sarasota, Tallahassee, Tampa, West Palm Beach

4 If actual building loads or fill height exceed our assumptions, then the recommendations in this report may not be valid. SPT Borings FIELD EXPLORATION PROGRAM The field exploration program included performing four (4) Standard Penetration Test (SPT) borings. The SPT borings were advanced to a depth of 20 feet below the ground surface using the methodology outlined in ASTM D One boring SB-3, was advanced to 25 feet deep after encountering very soft soils at 20 feet deep. A summary of this field procedure is included in the Appendix. Split-spoon soil samples recovered during performance of the borings were visually classified in the field and representative portions of the samples were transported to our laboratory in sealed containers. The groundwater levels at each of the boring locations were estimated during drilling. The borings were backfilled with soil cuttings. Test Boring Locations The approximate locations of the borings are schematically illustrated on a site plan shown on Figure 1 at approximately the locations requested. These locations were determined in the field by tape measuring/estimating distances from existing site features and should be considered accurate only to the degree implied by the method of measurement used. LABORATORY PROGRAM Representative soil samples obtained during our field sampling operation were packaged and transferred to our laboratory for further visual examination and classification. The soil samples were visually classified in general accordance with the Unified Soil Classification System (ASTM D-2488) and AASHTO M-145. The resulting soil descriptions are shown on the soil boring profiles presented on Figure 1. In addition, we conducted four (4) natural moisture content tests (ASTM D2216) and four (4) percent fines analyses (ASTM D1140). Two (2) Atterberg limits tests (ASTM D4318) were also attempted on selected soil samples obtained from the borings, however the samples were shown to be non-plastic. The results of our tests are presented adjacent to the sample depth on the boring profiles on Figure 1. General Soil Profile GENERAL SUBSURFACE CONDITIONS The results of the field exploration are graphically summarized on the soil boring profiles presented on Figure 1. The stratification of the boring profiles represents our interpretation of the 3

5 field boring logs and the results of laboratory examinations of the recovered samples. The stratification lines represent the approximate boundary between soil types. The actual transitions may be more gradual than implied. In general, our SPT soil borings initially encountered 6 to 12 inches of brown to dark brown fine sand with surficial roots and topsoil (Stratum 1) or an approximately 1 to 1.5-inch layer of asphaltic concrete underlain by a limerock base to a depth of approximately 5 to 6-inches atop Stratum 1 soils. Stratum 1 soils were typically underlain by approximately 5 to 9-feet of a light grayish tan silty to very silty fine sand (Stratum 2) to a depth of approximately 9 to 12-feet. Underlying Stratum 2 soils, we encountered a tan very silty fine sand to sandy silt (Stratum 3) to a depth of approximately 16 to 17-feet below land surface atop a tan and brown silty medium to fine sand sometimes with traces of hardpan (Stratum 4) to a depth of at least 20-feet. In soil boring SB-3, a gray slightly sandy lean to fat clay (Stratum 5) was observed to the termination of the boring at 25-feet. The Stratum 5 soil was observed to be very soft with weight of hammer (WOH) penetration across an approximately 1.5-foot thick layer at the depth of approximately 19.5-feet below land surface. WHO means that the Standard Penetration sample was advanced without impact and only by the weight of the hammer placed on the rods leading to the sampler. With the exception of the WOH soil observed in boring SB-3 at 19.5-feet below land surface, SPT N -values within the native soils typically ranged from loose to medium dense. SPT values were not obtained in the fill soils due to the requirement to advance the first 2-feet of the soil borings by hand. Groundwater Level Groundwater was generally encountered at a depth of 6.5 to 7-feet below land surface on the day our borings were advanced. Fluctuations in groundwater levels should be anticipated throughout the year primarily due to seasonal variations in rainfall and other factors that may vary from the time the borings were conducted. General ENGINEERING EVALUATION AND RECOMMENDATIONS The results of our exploration indicate that, with proper site preparation as recommended in this report, the existing soils are suitable for supporting the proposed buildings on a conventional shallow foundation system provided that a special foundation is utilized. Spread footings should provide an adequate support system for the structures. The following are our recommendations for overall site preparation and foundation support which we feel are best suited for the proposed facility and existing soil conditions. The recommendations are made as a guide for the design engineer and/or architect, parts of which should be incorporated into the project's specifications. 4

6 Stripping and Grubbing The "footprints" of the proposed buildings, plus an appropriate margin, should be stripped of all surface vegetation, stumps, debris, organic topsoil or other deleterious materials, as encountered. Specifically, the organic topsoil should be stripped. Buried utilities should be removed or plugged to eliminate conduits into which surrounding soils could erode. After stripping, the site should be grubbed or root-raked such that buried features and roots with a diameter greater than ½ inch, stumps, or small roots in a dense state, are completely removed. The actual depth(s) of stripping and grubbing must be determined by visual observation and judgment during the earthwork operation. All existing foundations, slabs, asphalt, and any other underground structures should be removed from the proposed construction area. If pipes or any collapsible or leak prone utilities are not removed or completely filled (with grout or concrete), they might serve as conduits for subsurface erosion resulting in excessive settlements. Any unsuitable existing fill soil should be removed and reworked or replaced. Over-excavated areas resulting from the removal of underground structures and unsuitable materials should be backfilled in accordance with the fill soils section of this report. Proof-rolling We recommend proof-rolling the cleared surface to locate any unforeseen soft areas or unsuitable surface or near-surface soils, to increase the density of the upper soils, and to prepare the existing surface for the addition of the fill soils. The proof-rolling should occur after cutting but before filling. Proof-rolling of the building areas should consist of at least 10 passes of a loaded dumptruck. Each pass should overlap the preceding pass by 30 percent to achieve complete coverage. If deemed necessary, in areas that yield, remove all deleterious material and/or moisture sensitive soils and replace with clean, compacted sand backfill. A density equivalent to or greater than 95 percent of the modified Proctor (ASTM D-1557) maximum dry density value is recommended for a depth of 1-foot below the bottoms of foundation and slab elevations. Areas receiving fill should also be compacted to 95 percent of the modified Proctor maximum dry density value to a depth of 1-foot below the cleared surface. Additional passes and/or overexcavation and recompaction may be required if these minimum density requirements are not achieved. The soil moisture should be adjusted as necessary during compaction. Care should be exercised to avoid damaging any neighboring structures while the compaction operation is underway. Prior to commencing compaction, occupants of adjacent structures should be notified and the existing condition (i.e. cracks) of the structures documented with photographs and survey (if deemed necessary). Compaction should cease if deemed detrimental to adjacent structures, and Ardaman & Associates should be notified immediately. Heavy vibratory compaction should be used with due caution within 200 feet of existing structures and hardscapes 5

7 as vibratory compaction may cause settlement of structures on loose sand within this margin and possibly beyond. Suitable Fill Material and Compaction of Fill Soils Fill materials should be free of organic materials, such as roots and vegetation. We recommend using fill with less than about 12 percent by dry weight of material passing the U.S. Standard No. 200 sieve size. Soils with more than about 12 percent passing the No. 200 sieve can be used in some applications, but will be more difficult to compact due to their inherent nature to retain soil moisture. We do not recommend using fill soils with percent passing the No. 200 sieve in excess of 35 percent, or with a liquid limit in excess of 40 and plastic index in excess of 10. Structural fill should be placed in level lifts not to exceed 12 inches in uncompacted thickness. Each lift should be compacted to at least 95 percent of the modified Proctor (ASTM D-1557) maximum dry density value. The filling and compaction operations should continue in lifts until the desired elevation(s) is achieved. If hand-held compaction equipment is used, the lift thickness should be reduced to no more than 6 inches. Foundation Support by Spread Footings and Foundation Compaction Criteria After the site preparation discussed in the previous report sections is complete, excavate the foundations to the proposed bottom of footing elevations. If plastic clay soils are encountered within the foundation excavations, they should be over-excavated to 1 foot below bottom of footings. Backfill these over-excavations in accordance with the recommendations provided above. Verify the in-place compaction beneath the footings for a depth of 1-foot below foundation grades. If necessary, compact the soils at the bottom of the excavations to at least 95 percent of the modified Proctor maximum dry density (ASTM D-1557) for a depth of 1-foot below the footing bottoms. In an abundance of caution, given the presence of WOH soils in Stratum 5, consider stiffening the foundation (conventional stiffening with added reinforcement or post tensioning) to mitigate the effects of differential movement of the foundations. Stiffening typically consists of increasing the percentage of steel reinforcement. Based on the conditions encountered, we estimate differential movement due to the plastic clays could be on the order of 1/2-inch in 20 feet. This differential movement may be used in design of the foundation. Based upon subsurface conditions encountered, it is our opinion that a shallow foundation system is appropriate for the proposed pad. Based on the existing soil conditions and, assuming the above outlined proof-rolling and compaction criteria are implemented, an allowable soil bearing pressure of 2,000 pounds per square foot (psf) may be used in the foundation design. This bearing pressure should result in foundation settlement within tolerable limits (i.e., maximum total settlement of 1-inch or less and maximum differential settlement of ½-inch or less). 6

8 All bearing wall foundations should be a minimum of 18 inches wide and column foundations 24 inches wide. A minimum soil cover of 18 inches should be maintained from the bottom of the foundations to the adjacent finished grades. Floor Slab Moisture Reducer and Slab Compaction Requirements Compaction beneath all floor slabs should be verified for a depth of 12 inches and meet the 95 percent criteria (modified Proctor, ASTM D-1557). Precautions should be taken during the slab construction to reduce moisture entry from the underlying subgrade soils. Moisture entry can be reduced by installing a membrane between the subgrade soils and floor slab. Care should be exercised when placing the reinforcing steel (or mesh) and slab concrete such that the membrane is not punctured. We note that the membrane alone does not prevent moisture from occurring beneath or on top of the slab. If foundations are isolated from the floor slab, an expansion joint should be provided around the columns and sealed with a water-proof sealant. QUALITY ASSURANCE We recommend establishing a comprehensive quality assurance program to verify that all site preparation and foundation and pavement construction is conducted in accordance with the appropriate plans and specifications. Materials testing and inspection services should be provided by Ardaman & Associates. As a minimum, an on-site engineering technician should monitor all stripping and grubbing to verify that all deleterious materials have been removed and should observe the proof-rolling operation to verify that the appropriate number of passes are applied to the subgrade and its response is suitable. In-situ density tests should be conducted during filling activities and below all footings, floor slabs and pavement areas to verify that the required densities have been achieved. In-situ density values should be compared to laboratory Proctor moisture-density results for each of the different natural and fill soils encountered. We recommend inspecting and testing the construction materials for the foundations and other structural components. IN-PLACE DENSITY TESTING FREQUENCY In North Florida, earthwork testing is typically performed on an on-call basis when the contractor has completed a portion of the work. The test result from a specific location is only representative of a larger area if the contractor has used consistent means and methods and the soils are practically uniform throughout. The frequency of testing can be increased and full-time construction inspection can be provided to account for variations. We recommend that the following minimum testing frequencies be utilized. 7

9 Following proof-rolling, the proposed building areas and existing, natural ground should be field density tested to a depth of 12 inches. Each 12-inch lift of fill should also be tested. Utility backfill should be tested at a minimum frequency of one in-place density test for each 12-inch lift for each 100 linear feet of pipe. Additional tests should be performed in backfill for manholes, inlets, etc. In proposed structural areas, the minimum frequency of in-place density testing should be reduced to one test for each 2,000 square feet of structural area. In-place density testing should be performed at this minimum frequency for a depth of 1-foot below natural ground and for every 1-foot lift of fill placed in the structural area. In addition, density tests should be performed in each column footing and every 50 linear feet of continuous or wall footings. Representative samples of the various natural ground and fill soils should be obtained and transported to our laboratory for Proctor compaction tests. These tests will determine the maximum dry density and optimum moisture content for the materials tested and will be used in conjunction with the results of the in-place density tests to determine the degree of compaction achieved. CLOSURE The analyses and recommendations submitted herein are based on the data obtained from the soil borings presented on Figure 1 and the assumed loading conditions. This report does not reflect any variations which may occur adjacent to or between the borings. The nature and extent of the variations between the borings may not become evident until during construction. If variations then appear evident, it will be necessary to re-evaluate the recommendations presented in this report after performing on-site observations during the construction period and noting the characteristics of the variations. In the event any changes occur in the design, nature, or location of the proposed facility, we should review the applicability of conclusions and recommendations in this report. We recommend a general review of final design and specifications by our office to verify that earthwork and foundation recommendations are properly interpreted and implemented in the design specifications. Ardaman and Associates should attend the pre-bid and preconstruction meetings to verify that the bidders/contractor understand the recommendations contained in this report. This study is based on a relatively shallow exploration and is not intended to be an evaluation for sinkhole potential. This study does not include an evaluation of the environmental (ecological or hazardous/toxic material related) condition of the site and subsurface. This report has been prepared for the exclusive use of in accordance with generally accepted geotechnical engineering practices for the purpose of development of the proposed townhomes. No other warranty, expressed or implied, is made. 8

10 We are pleased to be of assistance to you on this phase of the project. When we may be of further service to you or should you have any questions, please contact us. Very truly yours, ARDAMAN & ASSOCIATES, INC. Certificate of Authorization No Steven W. Reecy, P.E. Michael S. Wilson, P.E. Senior Project Engineer Senior Engineer / Branch Manager Florida License Florida License SWR/MSW/mss 9

11 APPENDIX Standard Penetration Test and Auger Boring Procedures

12 STANDARD PENETRATION TEST The standard penetration test is a widely accepted test method of in situ testing of foundation soils (ASTM D 1586). A 2-foot long, 2-inch O.D. split-barrel sampler attached to the end of a string of drilling rods is driven 18 inches into the ground by successive blows of a 140-pound hammer freely dropping 30 inches. The number of blows needed for each 6 inches of penetration is recorded. The sum of the blows required for penetration of the second and third 6-inch increments of penetration constitutes the test result or N-value. After the test, the sampler is extracted from the ground and opened to allow visual examination and classification of the retained soil sample. The N-value has been empirically correlated with various soil properties allowing a conservative estimate of the behavior of soils under load. The tests are usually performed at 5-foot intervals. The test holes are advanced to the test elevations by rotary drilling with a cutting bit, using circulating fluid to remove the cuttings and hold the fine grains in suspension. The circulating fluid, which is a bentonitic drilling mud, is also used to keep the hole open below the water table by maintaining an excess hydrostatic pressure inside the hole. In some soil deposits, particularly highly pervious ones, NX-size flush-coupled casing must be driven to just above the testing depth to keep the hole open and/or prevent the loss of circulating fluid. Representative split-spoon samples from the soils are brought to our laboratory in air-tight jars for further evaluation and testing, if necessary. Samples not used in testing are stored for 30 days prior to being discarded.

13 SHEET TITLE: DRAWN BY: ART CHECKED BY: SWR DATE: FILE NO. APPROVED BY: FIGURE