W912HN-23-B-3000 BECC319022 RAFB Bldg 125 Geotech-Env Report 200715.pdf

JULY 15, 2020

REPORT OF SUBSURFACE

EXPLORATION AND

LIMITED SCOPE ENVIRONMENTAL

SCREENING FOR

Robins Air Force Base-Building 125 Renovations Building 125-Robins AFB

Warner Robins, Georgia 31098

BECC Project Number: 319022

PREPARED FOR:

Mason and Hanger

C/O Warren Foy 300 W. Vine Street

Lexington, Kentucky 40507

GEOTECHNICAL, MATERIALS, AND ENVIRONMENTAL ENGINEERS

360 Industrial Lane, Birmingham, AL 35211 - (205) 941-1119 - www.beccinc.com

LISA K. MORRISON

CEO

MARTIN T. BURFORD, P.E.

President

RICHARD A. RHINEHART, P.E.

Senior Vice President

October 12, 2021

Geotechnical, Materials & Environmental Engineers 360 Industrial Lane | Birmingham, Alabama 35211

Ph. (205) 941-1119 | Fax (205) 941-1198 www.beccinc.com

Mr. Warren Foy

300 W. Vine Street Lexington, Kentucky 40507

Subject: Letter of Addendum to Geotechnical Engineering Evaluation

With Limited Scope Environmental Screening for Robins Air Force Base-Building 125 Renovations Warner Robins, Georgia BECC Project Number: 319022

Dear Mr. Foy:

BECC has evaluated the geotechnical findings as discussed in our report dated July 15, 2020. BECC stated the soil conditions encountered at the time of exploration (March 17, 2020) that conditions in B1 were adequate to support existing load conditions of Building 125. However, conditions in B2 may require re-conditioning due to loose clayey sands encountered during exploration. At your request BECC determined an allowable bearing capacity of new structure foundations. Based on the expected loads of 30 kips as provided, BECC recommends an allowable bearing capacity of 4,000 pounds per square foot (psf) with footings extending a minimum of 5 feet below the slab surface elevation. Settlement of new structures are anticipated to be less than 0.50 inch based on this loading. All recommendations stated in the geotechnical report should be followed (see Sections 8 and 9 of the original report).

A revision to the Seismic Design Parameters in Section 4.1 was also made. We recommend a seismic site class definition of “C” be used in design calculations (International Building Code). The following parameters should be used:

Site Location: N 32.626035 0 W -83.5928720

We greatly appreciate the opportunity to assist you on this project. If you have any questions, feel free to contact us.

Respectfully submitted, BECC, Inc.

Jeremy Mitchell, P.E. Richard A. Rhinehart, P.E.

Technical Services Division Manager Principal Geotechnical Engineer

Fa Fv SS SMS SDS S1 SM1 SD1

1.3 1.5 0.170 0.221 0.148 0.075 0.112 0.075

LISA K. MORRISON

CEO

MARTIN T. BURFORD, P.E.

President

RICHARD A. RHINEHART, P.E.

Senior Vice President

July 15, 2020

Geotechnical, Materials & Environmental Engineers 360 Industrial Lane | Birmingham, Alabama 35211

Ph. (205) 941-1119 | Fax (205) 941-1198

Mr. Warren Foy

300 W. Vine Street Lexington, Kentucky 40507

Subject: Report of Subsurface Exploration and Geotechnical Engineering Evaluation

With Limited Scope Environmental Screening for Robins Air Force Base-Building 125 Renovations Warner Robins, Georgia BECC Project Number: 319022

Dear Mr. Foy:

BECC, Inc. has completed the authorized Subsurface Exploration and Geotechnical Engineering Evaluation for the subject project. This work was conducted in accordance with our proposal Q1-19125 dated August 28, 2019.

The purpose of BECC’s work was to perform a subsurface exploration and geotechnical engineering evaluation with limited scope environmental screening for the proposed addition of a second floor mezzanine in Building 125 located on Robins Air Force Base in Warner Robins, Georgia. This report outlines the exploration procedures used, exhibits the data obtained, and presents our conclusions and recommendations.

We sincerely appreciate the opportunity to have worked with you on this project. If you have any questions, or if we may be of further service to you, please call us.

Respectfully submitted, BECC, Inc.

Jeremy Mitchell, P.E. Richard A. Rhinehart, P.E.

Technical Services Division Manager Principal Geotechnical Engineer

Warner Robins AFB-Bldg 125 Renovations Robins AFB-Bldg 125, Warner Robins, GA

BECC Project #319022

Report for Subsurface Exploration & Geotechnical Engineering Evaluation With Limited Scope Environmental Screening July 15, 2020 Page 2 of 17

TABLE OF CONTENTS

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Table of Contents

SECTION 1: EXECUTIVE SUMMARY

SECTION 2: SCOPE OF WORK

SECTION 3: PROJECT DESCRIPTION

SECTION 4: SITE GEOLOGY

4.1 SEISMIC DESIGN PARAMETERS

SECTION 5: SUBSURFACE EXPLORATION

5.1 FIELD EXPLORATION

5.2 LABORATORY ANALYSIS

SECTION 6: LABORATORY TESTS

6.1 DESCRIPTION OF SOILS (VISUAL-MANUAL PROCEDURE)(ASTM D2488)

6.2 NATURAL MOISTURE CONTENT (ASTM D2216)

6.3 PERCENT PASSING #200 SIEVE (ASTM D1140)

6.4 ATTERBERG LIMITS TESTS (ASTM D4318)

SECTION 7: SUBSURFACE CONDITIONS

7.1 SURFACE MATERIAL

7.2 SUBSURFACE SOILS

7.3 GROUNDWATER

7.4 LIMITED SCOPE ENVIRONMENTAL SCREENING OF SUBSURFACE SOILS

7.4.1 Findings & Conclusions

SECTION 8: FOUNDATION RECOMMENDATIONS

8.1 BEARING CAPACITY AND SETTLEMENT OF SOILS

8.2 GENERAL SPREAD FOUNDATION AND SOIL PROTECTION RECOMMENDATIONS

SECTION 9: SITE PREPARATION & GRADING CONSIDERATIONS

9.1 EXISTING STRUCTURES

9.2 EXCAVATION CONSIDERATIONS

9.3 CONDITIONING OF SUBGRADE SOILS

9.4 CONTROLLED STRUCTURAL FILL

9.5 BACKFILLING OF TRENCHES

9.6 SUBSURFACE DRAINAGE & PROTECTION OF SOILS DURING GRADING

SECTION 10: FLOOR SLAB ANALYSIS

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SECTION 11: CONSTRUCTION MONITORING

11.1 SUBGRADE OBSERVATION, PROOFROLLING

11.2 FILL MONITORING

11.3 FOUNDATION EXCAVATIONS

SECTION 12: GENERAL REMARKS/REPORT LIMITATIONS

APPENDICES

APPENDIX A – Maps

APPENDIX B – Boring Logs & Subsurface Laboratory Summary

APPENDIX C – Environmental Laboratory Reports

APPENDIX D – Chain of Custody (COC)

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REPORT

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SECTION 1: EXECUTIVE SUMMARY

The project will consist of the construction of a mezzanine second level in a former machine shop at Building 125 at Robins AFB in Warner Robins, GA. The following is a brief summary of the exploration including our findings, conclusions and recommendations. Refer to subsequent sections within the text for detailed discussions of these topics.

The existing floor slab was approximately 6 inches in thickness with a wire mesh reinforcing mat located near or at the bottom of the slab.

Subsurface soils encountered were typically brown to orange and white in color and of a dense to very dense silty clayey sand from below the slab to 20 feet. With exception, B2 exhibited very loose to loose consistency in the upper 5 feet.

It is our understanding that loads are not expected to exceed existing building loads. Conditions encountered in B1 should be adequate to support such loads. However, should an increase in soil loading be required in the area of B2, soil reconditioning may be required. This reconditioning may require soil treatments, recompaction, or extending foundation depths. Final design plans were not available as of the date of this report. When final plans are available, BECC should be allowed to review the plans to evaluate with conditions encountered and described herein.

If require, new structural engineered fill soils should be compacted to a minimum of 98% of the Standard Proctor maximum dry density (ASTM D 698) at a moisture content within optimum to +/- 2% of the soil’s optimum moisture content. The highly plastic soils encountered at the site will not be suitable for use as controlled structural fill.

Environmental sampling of subsurface encountered contaminant below regulatory thresholds including

Acenaphthene, Anthracene, Benzo(a)anthracene, Benzo(b)fluoranthene, Benzo(k)fluoranthene, Benzo(a)pyrene, Chrysene, Fluoranthene, Fluorene, Phenanthrene, and Pyrene. These contaminants were encountered primarily in the upper 5 feet, predominantly in location B1.

NOTE: It should be noted that this executive summary presents selected elements of our findings and recommendations only. It does not present crucial details needed for the proper application of our findings and recommendations. Our findings, recommendations, and application are related only through the full report, and are best evaluated with the active participation of the geotechnical engineer who developed them.

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SECTION 2: SCOPE OF WORK

The purpose of the geotechnical exploration was to evaluate general subsurface conditions within the site and to gather and present data for the additional mezzanine structure in Building 125 at Robins AFB in Warner Robins, GA.

This work was conducted in accordance our proposal number Q1-19125 dated August 28, 2019. A geotechnical evaluation/environmental screening of the existing concrete slab and subsurface soils was performed via soil borings in the machine shop. The following items were included as part of our scope of work:

1. Two (2) soil test borings drilled in the proposed building and paving areas to a depth of 20 feet below the existing ground surface or auger refusal, whichever is less.

2. Laboratory tests included natural moisture content, Atterberg limits and percent passing #200 sieve.

3. A geotechnical engineering report is to include the following items:

A site plan illustrating the boring locations Boring logs describing the subsurface and groundwater conditions encountered Description of field and laboratory procedures Discussion of site geology Results of the laboratory tests performed Presence of unsuitable soils within the borings (if applicable) Recommendations for undercutting unsuitable soils General earthwork recommendations (compaction) Recommendations for foundation design Analysis of existing floor slab conditions Environmental analysis for contaminants

NOTE: Our scope of work within this report did include evaluation of surface or subsurface environmental conditions normally associated with Phase II Environmental Assessments with limited scope.

SECTION 3: PROJECT DESCRIPTION

The subject site is located on the grounds of Robins Air Force Base in Warner Robins, Georgia. The conference room on level 2 of the hanger is planned to be extended over the existing machine shop area and founded on new piers and columns. The machine shop has been mostly cleared of equipment and material. Soil classification tests were performed in BECC’s lab for the purpose of evaluating and providing geotechnical engineering recommendations for foundations. Select soil samples were also analyzed for potential contaminants.

Environmental samples were gathered and delivered to Sutherland Environmental Company, Inc., in Birmingham, Alabama, for analysis.

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SECTION 4: SITE GEOLOGY

Based on published geological information from the United States Geological Survey (USGS), the Site is underlain by Eocene undifferentiated. These deposits are highly weathered sands and sandy clays of lower Tertiary age.

4.1 Seismic Design Parameters

The subsurface conditions at the site consist of a shallow layer of existing fill and residual sandy clays underlain by sandstone. Based on the borings performed at the site and our knowledge of the site geology, we recommend a seismic site class definition of “C” be used in design calculations (International Building Code). Site Coefficient values for spectral response acceleration taken from the International Building Code and the USGS are given below.

Site Location: N 32.626035 0 W -83.5928720

SECTION 5: SUBSURFACE EXPLORATION

5.1 Field Exploration

BECC performed two (2) soil test borings (designated B1 and B2) on March 17, 2020. The borings were drilled to depths of 20 feet below existing ground surface. The boring locations were located in the field by BECC's engineers by taping distances and estimating right angles, therefore the locations shown on the “Boring Location Plan” in Appendix A- Maps should be considered approximate.

Soil drilling and sampling operations were conducted according to ASTM D 1586. The test borings were advanced by mechanically twisting continuous steel auger flights. Within the test borings, soil samples were obtained with a standard 1.4 inch I.D., 2 inch O.D. split spoon sampler. The sampler was first seated 6 inches to penetrate any loose cuttings and was then driven an additional 12 inches with blows of a 140 pound hammer falling 30 inches.

The number of blows (N) required to drive the sampler the final 12 inches of penetration is the “Standard Penetration Resistance”. The penetration resistance, when properly evaluated, is an index of the soil strength.

Fa Fv SS SMS SDS S1 SM1 SD1

1.3

1.5 0.267 0.348 0.232 0.124 0.185 0.124

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5.2 Laboratory Analysis

Samples were obtained from borings in the manner previously described. Geotechnical samples were gathered in plastic bags for transport to the laboratory (BECC, Inc.). Additional samples for environmental laboratory evaluation were placed in glass jars and secured on ice for immediate transport to the laboratory (Sutherland Environmental Company, Inc.) in Birmingham, Alabama. Laboratory analysis of soils included the following tests and standards:

Geotechnical Analysis: Description of Soils (ASTM D2488), Natural Moisture Content (ASTM D2216), Percent Passing #200 Sieve (ASTM D1140), and Atterberg Limits Tests (ASTM D4318).

Environmental Analysis: Metallic Analytes in TCLP Extract (SW846 1311/6010B/7470A), Volatile Organic Compounds (VOCs) in TCLP Extract (SW846 Method 1311/8260B), Semi-Volatile Organic Compounds (SVOCs) in TCLP Extract (SW846 Method 1311/8270C), Regulated Pesticides in TCLP Extract (SW846 1311/8081), Polynuclear Aromatic Hydrocarbons (PAHs) (EPA Method 8270C), Flashpoint (SW846 Method 1030), and Paint Filter Test (SW846 Method 9095A).

SECTION 6: LABORATORY TESTS

In addition to the field exploration, a limited laboratory testing program was conducted to ascertain additional engineering characteristics of the foundation materials. To supplement the visual classification of the soil samples, the following tests were performed. The results are shown on the Boring Logs and the “Geotechnical Lab Summary” table in Appendix B – Boring Logs & Geotechnical Laboratory Summary.

6.1 Description of Soils (Visual-Manual Procedure)(ASTM D2488)

The soil samples were visually examined by our engineer and soil descriptions were provided. Representative samples were then selected and tested to determine soil classification as described above. This data was used to correlate our visual descriptions with the Unified Soil Classification.

6.2 Natural Moisture Content (ASTM D2216)

Natural moisture contents (M%) were determined on selected samples. The natural moisture content is the ratio, expressed as a percentage, of the weight of water in a given amount of soil to the weight of solid particles.

6.3 Percent Passing #200 Sieve (ASTM D1140)

Wash #200 tests were performed on the selected samples to determine the amount of “fines” in the represented soil. “Fines” are defined as particles with a grain size equal to or less than a diameter of 0.075 millimeters. These particles are typically found in silts, clays, and silty clays, as well as silty or clayey sands.

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6.4 Atterberg Limits Tests (ASTM D4318)

Atterberg Limit tests were performed on the selected samples to determine how the characteristics change upon variation in moisture stage. The limits are bracketed by the Liquid Limit (LL) and the Plastic Limit (PL). The Liquid Limit is the moisture content at which the soil will flow as a heavy viscous fluid. The plastic Limit is the moisture content at which the soil is between the “plastic” and semi-solid stage. The soil’s Plasticity Index (PI) is the difference between the Liquid Limit and the Plastic Limit. The PI is often used as the indicator of the soil’s expansive tendencies. The greater the range between the LL and the PL, the more potentially expansive the soil can be.

SECTION 7: SUBSURFACE CONDITIONS

Details of the subsurface conditions encountered by the test borings are shown on the "Log of Boring" sheets in Appendix B – Boring Logs & Geotechnical Laboratory Summary. The general subsurface conditions encountered, and their pertinent characteristics are described in the following paragraphs. The stratification lines indicated on the logs of boring represent approximate boundaries between soil types. However, the actual transition may be gradual.

Conditions represented by the test borings should be considered applicable only at the test boring locations on the dates shown, and it should be assumed that the conditions may be different at other locations at other times.

7.1 Surface Material

7.2 Subsurface Soils

The subsurface soils consisted of very loose to very dense silty to sometimes clayey sand extending from just below the concrete slab to approximately 5 feet below surface grade (BSG). Mid-range soils consisted similar soils ranging from silty clays to silty sands, orange to light brown in color to 15 feet BSG with consistency ranging from medium dense/very stiff to dense/hard. Deep soils extending from 15 feet to 20 feet BSG were light brown gray sands with medium dense consistency. Standard Penetration Tests (N-values) in the subsurface soils ranged from 4 to 100+ blows per foot (bpf). The N-values of 100+ were exaggerated due to the presence of gravel or chert. The lower N-values were encountered at B2 from just below the concrete slab to 5 feet BSG. The following table summarizes consistency of soils encountered:

Table 7.2.1

DEPTH (ft) B1 (N-Values) B2 (N-Values) 0 – 0.5 N/A N/A

0.5 – 5 18 – 52 4 – 5 5 – 15 22 – 100+ 16 – 35 15 -20 15 12

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Laboratory tests were performed on select samples of the subsurface soils. Natural moisture contents ranged from 6.4% to 20.0% with less moisture encountered between 0 and 5 feet BSG. Three (3) Atterberg Limits tests were performed on the soils. The tests indicated a Liquid Limit (LL) from 17 to 23, Plasticity Index (PI) from 1 to 6, with 30.5% to 43.3% of material passing a #200 sieve. Based on laboratory tests performed, the soils were classified as silty sands (SM) and silty clayey sands (SC-SM). A detailed laboratory summary can be found in Appendix B.

The soil classification tests performed are as follows:

Table 7.2.2

BORING DEPTH

(FT.)

ATTERBERG LIMITS % FINES (Clay &

Silt)

UNIFIED SOIL

CLASSIFICATION LL PL PI

B-1 1 to 2.5 17 16 1 30.5 SM B-2 3.5 to 5 19 15 4 40.7 SM-SC B-2 8.5 to 10 23 17 6 43.3 SM-SC

7.3 Groundwater

Groundwater was encountered in each soil borings at a depth of 10 feet BSG. The groundwater encountered displace up the auger stem, indicating the potential presence of high hydraulic conductivity in the deeper sands and gravel encountered in each boring location. The presence or absence of water in the borings at the time of drilling does not necessarily mean that groundwater will or will not be present at other times. Groundwater levels fluctuate seasonally and are related to the amount of rainfall received in months prior to the observations.

7.4 Limited Scope Environmental Screening of Subsurface Soils

Composition samples were taken from each boring location from the top 5 feet (below the concrete slab) to 5 feet and from 5 to 10 feet BSG. These samples were collected into glass jars and immediately placed on ice. The samples were transported to Sutherland Environmental in Birmingham, Alabama, within 24 hours of extraction.

The samples were tested for the following in soils:

RCRA 8 Heavy Metals in TCLP (SW846 EPA Method 1311/6010B/7470A);

Volatile Organic Compounds (VOCs) in TCLP (SW846 EPA Method 1311/8260B);

Semi-VOCs in TCLP (SW846 EPA Method 1311/8270C);

Regulated Pesticides in TCLP (SW846 EPA Method 1311/8081);

Polynuclear Aromatic Hydrocarbons (PAHs) (EPA Method 8270C);

Flashpoint (SW846 EPA Method 1030); and Paint Filter Test (SW846 EPA Method 9095A).

Based on the use of this space as a machine shop for metals, contaminants such as RCRA 8 heavy metals, solvents (VOCs and SVOCs), lubricants, and other chemicals are suspect as a possible Contaminants of Concern (COCs) for impact.

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7.4.1 Findings & Conclusions

Based on the screening investigation under the limited scope described in this report, no impact from VOCs or SVOCs was encountered in soil samples from either boring location. Barium was the only RCRA metal encountered between 0.3 parts per million (ppm) to 0.8-ppm in both boreholes. These levels are below regulatory thresholds. Flashpoint in each sample were all below 2.0 mm/s and each sample passed the paint filter test.

Several samples were found to be impacted by PAHs but below regulatory thresholds for screening values and TCLP waste values. The laboratory analytical reports can be found in Appendix C – Environmental Laboratory Reports and the inspection chain of custody forms can be found in Appendix D – Chain of Custody (COC). The following table summarizes those findings:

Table 7.4.1 DEPTH (ft) B1 (Contaminants –in ppm) B2 (Contaminants –in ppm)

0.5 - 5

Acenaphthene – 0.098 Anthracene – 0.116

Benzo(a)anthracene – 0.168 Benzo(b)fluoranthene – 0.110 Benzo(k)fluoranthene – 0.156

Benzo(a)pyrene - 0.120 Chrysene – 0.202

Fluoranthene – 0.535 Fluorene – 0.070

Phenanthrene – 0.448 Pyrene – 0.383

Benzo(k)fluoranthene – 0.060 Chrysene – 0.067

Fluoranthene – 0.138 Phenanthrene – 0.077

Pyrene – 0.111

5 – 10 BDL

Fluoranthene – 0.056 Phenanthrene – 0.054

Pyrene – 0.051 NOTE: A COC List can be found in Appendix C with levels compared to EPAs Region 4 Screening Levels (RSLs).

Based on the findings and conditions stated within this report, it is BECC’s opinion that the property is not impacted by suspected COCs associated with the AOCs stated herein. The metals encountered in soil samples are natural occurring within the geological region and levels detected are indicative of a naturally occurring condition. It is BECC’s opinion excavation of the subsurface soils is not expected to be limited by the conditions encountered in this screening.

SECTION 8: FOUNDATION RECOMMENDATIONS

The recommendations stated in the following sections are based on the data obtained through our exploration and experience with similar structures and subgrade conditions. Detailed foundation loads were not available to BECC at the time of this report. However, we understand structure loads are expected to be similar to existing foundation loads. If building loads are different from those described in this report, BECC should be notified and given the opportunity to review our recommendations in light of such changes.

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8.1 Bearing Capacity and Settlement of Soils

It is our understanding that loads are not expected to exceed existing building loads. Conditions encountered in B1 should be adequate to support such loads. However, should an increase in soil loading be required in the area of B2, soil reconditioning may be required (See Section 9.2). This reconditioning may require soil treatments, recompaction, or extending foundation depths. Final design plans were not available as of the date of this report.

When final plans are available, BECC should be allowed to review the plans to evaluate with conditions encountered and described herein.

8.2 General Spread Foundation and Soil Protection Recommendations

The following items should be included in the project specification in regard to spread foundation design and construction.

1. We recommend minimum footing dimensions of 18 and 24 inches for continuous strip footings and individual column footings, respectively.

2. The footing bearing surface should be observed by a BECC geotechnical engineer or his representative to verify that the soil complies with the above recommendations.

3. Where it is necessary to extend a footing beyond the planned bearing depth in order to reach a suitable bearing level, the over-excavation should be backfilled with compacted engineered clay fill or lean concrete.

4. If water is encountered in the footing excavations, extreme care should be exercised to ensure that the foundation subgrade is not disturbed. A thin concrete “mud mat” poured over surfaces should be used to protect them from any seepage which might enter foundation excavations.

5. If possible, all footing concrete should be poured during the same day the excavation is made. If this is not possible, then the footing excavation should be adequately protected.

6. Backfill adjacent to exterior walls should be composed of clean soil fill meeting the project fill requirements. No debris or rubble should be placed adjacent to the exterior walls. Fill should be compacted immediately after placement to preclude surface water infiltration into the foundation materials.

SECTION 9: SITE PREPARATION & GRADING CONSIDERATIONS

A foundation plan or proposed structure detail were not available to BECC at the time of this geotechnical engineering report. The recommendations contained in this report may need modifications once the finished plans are determined. BECC should be supplied this information by the owner when it becomes available.

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9.1 Existing Structures

All existing structures (including above and below ground construction) within the areas to be developed should be removed. Removal should include all underground pipes and lines, utilities, etc., that might interfere with construction. If abandoned underground utilities are to be removed prior to initiation of construction, provisions should be made in the construction specifications and budget to restore the subgrade to a stable condition.

Restoration should include backfilling and compaction of the excavated areas.

9.2 Excavation Considerations

The subsurface conditions that will have a major impact on site development is the presence of very loose sands encountered in B2 just below the concrete slab to 5 feet. Settlement of foundation founded over the low consistency soils in B2 is a concern. Groundwater conditions below 10 feet may require extensive dewatering measures should subsurface structures be planned beyond 10 feet BSG.

9.3 Conditioning of Subgrade Soils

Following the removal of surface materials or unsuitable soils, areas that are at grade or are to receive fill should be evaluated by the geotechnical engineer. This observation may include proofrolling with a loaded dump truck or other pneumatic-tired construction equipment or geotechnical probe evaluation. The geotechnical engineer, by field examination, can determine the extent of any undercutting or reconditioning necessary to prepare an adequate subgrade. Replacement with controlled structural fill should meet the requirements of Section 9.4 of this report. The construction budget should have undercutting and backfilling allowances.

In addition to proofrolling, the exposed surface soils in building and paving areas should be recompacted to a minimum of 98% of the soil’s maximum dry density (ASTM D698), at a moisture content at optimum to +/- 2% of the soil’s optimum moisture content.

9.4 Controlled Structural Fill

BECC recommends that the controlled structural fill meet the following recommendations:

1. Have a Unified Soil Classification of SM, SC, or SM-SC with a minimum of 30% passing the #200 sieve.

2. Have a maximum Liquid Limit (LL) less than 50.

3. Have a maximum Plasticity Index (PI) less than 30.

4. Be free of organics, debris and rocks greater than 4 inches

5. Have a maximum dry density greater than 100 pcf

The fill should be compacted to a minimum 98 percent of maximum dry density, as determined by the Standard Proctor ASTM D698. A sufficient number of field density tests should be performed to evaluate the grading contractor's performance during filling. During mass grading, lift thickness for fill should be limited to a maximum of eight inches loose measure. Backfilling in limited access areas such as utility trenches should have a lift thickness limited to six inches loose measure.

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It is also recommended that all structural fill be placed at optimum to +/- 2% of optimum moisture content. The grading contractor should acknowledge the importance of proper fill moisture conditioning. We suggest that the project specifications address that both fill compaction and acceptable fill moisture content will be required for the acceptance of structural fills.

9.5 Backfilling of Trenches

Backfilling of utility or foundation trenches is often accomplished in an uncontrolled manner, leading to subsequent settlement of the fill and cracking of pavements. It is recommended that utility trenches be backfilled with acceptable fill in six-inch lifts and compacted with pneumatic-piston tampers to the project requirements. Should seepage occur in utility trenches, it may be necessary to "floor" the trench with open-graded gravel to provide a dry working surface.

9.6 Subsurface Drainage & Protection of Soils During Grading

The soils at the site are moisture sensitive and can become easily disturbed causing loss of strength. Proper drainage around trenches from water infiltration will be very important during foundation construction. If the soils become wet after being exposed it may become necessary to undercut or recondition. On many projects reworking of disturbed soils becomes a point of controversy. BECC recommends that the specifications for this project provide performance guidelines for protection of exposed soils and correction of disturbed areas as well guidelines for sumping water from foundation excavations within a building enclosure.

Subgrade soils in building and paving areas should not be allowed to dry below the soils’ optimum moisture content limit. During the dryer times of the year, periodic wetting of the subgrade soils will be needed to maintain moisture in the subgrade.

SECTION 10: FLOOR SLAB ANALYSIS

Approximately 6 inches of concrete slab was encountered at each boring location. Each boring location was cored and visually analyzed for reinforcing, abnormalities, etc. Each core had wire mesh reinforcement. Core B1 encountered wire mesh approximately 2 inches from the core bottom. Core B2 encountered wire mesh near the bottom.

If additional floor slab must be removed for construction purposes and replaced, we recommend soils in those floor slab areas be compacted to a minimum of 98% of the Standard Proctor maximum dry density (ASTM D 698).

We recommend a minimum of 4 inches of #57 crushed stone or 6 inches of #610 crushed stone be placed above the final subgrade in order to act as a capillary break. A maximum particle size of one inch is recommended for the underslab granular material. We recommend that any slab portions requiring replacement be replaced in similar buildup or greater as the existing slab, and slab joints and construction be in accordance with the guidelines of the American Concrete Institute (ACI) and the Portland Cement Association (PCA).

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Prior to the construction of floor slabs, the subgrade should be evaluated by a geotechnical engineer. This evaluation may include proofrolling. We suggest that provisions be included in the project specifications for the contractor to restore the subgrade soils to an acceptable condition, (as discussed in this report) prior to the construction of slabs. Such restoration may include moisture conditioning of the surficial soils and recompaction to the project requirements.

SECTION 11: CONSTRUCTION MONITORING

We strongly recommend that BECC, Inc. be retained to provide a comprehensive construction-monitoring program when the project proceeds. This prom would assist the owner in determining that the work is being carried out in general conformance with the plans and specifications and help avoid the potential of change orders and cost overruns. Construction monitoring includes testing of construction materials such as compacted fill and concrete. Also included is engineering observation during the site preparation, foundation and wall construction phases of the project.

Monitoring/testing during the earthwork and foundation construction phases is particularly important since assumptions (and recommendations) have been made based on the soil boring data. Confirmation that actual subsurface conditions are comparable to the assumed conditions is an essential part of the subsurface exploration process.

11.1 Subgrade Observation, Proofrolling

The purpose of proofrolling will be to densify the exposed near-surface soils and to reveal soft pockets of soil that will require remedial measures. Areas that pump or rut during the proofrolling operations should be undercut or reconditioned. The geotechnical engineer can determine the depth and extent of areas that will require undercutting.

11.2 Fill Monitoring

BECC recommends that in-place density tests should be performed in the field by an engineering technician to evaluate the contractor's performance with regard to meeting the project specifications for fill placement. A commonly used testing frequency is one test per eight inch lift to fill placed per 2,500 square feet of fill area. The engineering technician can assist the grading contractor in soil moisture content evaluation by performing on-site fill moisture content tests.

11.3 Foundation Excavations

It is recommended that the excavations for foundations be observed and tested by a BECC representative. Such testing is necessary to determine the appropriateness of the bearing level, the adequacy of the bearing materials and the conformity of the foundation to the specification with respect to depth, planned dimensions, cleanliness, etc.

With Limited Scope Environmental Screening July 15, 2020 Page 17 of 17

SECTION 12: GENERAL REMARKS/REPORT LIMITATIONS

This report has been prepared for the exclusive use of Mason and Hanger for specific application to the subject project. All recommendations contained in this report have been made in accordance with generally accepted soil and foundation engineering practices. No other warranties are implied or expressed. In addition, the analysis and recommendations submitted in this report are based in part upon the data obtained from the soil test borings. The nature and extent of variations between the test locations may not become evident until construction. If variations then appear evident, it may be necessary to re-evaluate the recommendations of this report.

We emphasize that this report was for design purposes only and is not sufficient to prepare an accurate bid.

Contractors reviewing this report should acknowledge that the recommendations and discussions herein are for design purposes.

If significant changes are made in the character of the proposed development, a consultation should be arranged to review them with respect to prevailing subsurface conditions. At that time, it may be necessary to submit supplementary recommendations.

It is imperative that the geotechnical engineer be provided the opportunity to review the final plans and specifications to verify that the recommendations in this report are properly interpreted and incorporated in the design. It will be the client's responsibility to furnish the final grading and foundation plans to BECC for the necessary review. If the geotechnical engineer is not accorded the privilege of making this recommended review, we can assume no responsibility for misinterpretation of our recommendations.

APPENDIX A

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P O

V

MED

ACC

MED

ACC

MED

ACC

MED

ACC

DP

HAND

SINK

SALAD

BAR

DELI

SERVICE

STAND-UP

COOLER

W/C

SERVICE

W/C

SERVICE

W/C

SERVICE

ICE

CREAM

C O

O

LE

R C

O O

LE

R

C O

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P D

T O

B A

C C

O

C H

E C

K O

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IS

T E

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F O

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IN

N

A C

H O

H O

T D

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CHIPS/SNACKS

C O

F F

E E

T

E A

THIS AREA WILL

INCLUDE THE

FOLLOWING:

DRY STORAGE, WALK

IN COOLER,

PREP, WASH,

ELECTRICAL, COMM

AND JANITOR ROOMS.

C.F.

15X22

OFFICE

15X15

OFFICE

15X15 C.F.

15X22

OFFICE

15X15

OFFICE

15X15C.F.

15X24

MEC. ROOM

17X19

COMM.

ROOM

8X19

NEW OFFICE SPACE & RESTROOMS FOR 124 EMPLOYEES

ABOVE B125 PROPOSED BREAK AREA 14,900 SF.

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WOMEN'S SHOWERS & LOCKERS

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MENS SHOWERS & LOCKERS

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MENS REST ROOM

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WOMEN'S REST ROOM

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FRIG

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FRIG

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FRIG

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ICE

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MACHINES

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VENDING

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MACHINES

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MACHINES

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MACHINES

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WOMEN'S REST ROOM

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MENS REST ROOM

APPENDIX B

SM 176.6

11.5

16.9

Groundwater encountered at 10'

Approximately 6" of CONCRETE

Medium Dense, Brown Silty Clayey SAND

Very Dense, Brown Silty SAND

Medium Dense, Orange Clayey Silty SAND

Dense, Orange Clayey Silty SAND

Very Hard, Light Brown Silty CLAY

Medium Dense, Light Brown Gray SAND

Soil Boring terminated at 20.0 feet

SS

SS

SS

SS

SS

SS

30.5

12-10-8

(18)

16-24-28

(52)

20-11-11

(22)

16-17-18

(35)

24-42-50/1

(100+)

5-7-8

(15)

HOLE DIAMETER 6 inches

GROUND ELEVATION

CONTRACTOR Geolab Environmental Drilling

REVIEWED BY R.Rhinehart

GEOLOGY Eocene Undifferentiated

BORING LOCATION See Map

BORING NUMBER B-1

PROJECT AFB Building 125 Renovation

LOGGED BY J.Mitchell

DATE COMPLETED 3/17/20

METHOD Hollow Stem Auger

BECC PROJECT NO. 319022

D E

P T

H (f t)

SPT N VALUE

20 40 60 80

BORING NUMBER - B-1

U N

IF

IE

D C

LA

S

S

IF

IC

A

T

IO

N

LI

Q

U

ID

LI

M

IT

G R

A P

H

IC

LO

G

M O

IS

T

U R

E C

O N

T E

N T

P

LA

S T

IC

IT

Y

IN

D E

X

NOTESMATERIAL DESCRIPTION

E

LE

V A

T

IO

N (f t)

S A

M P

LE

T

Y P

E N

U M

B E

R

F

IN

E S

C O

N T

E N

T

W A

T E

R

LE

V E

L

R E

C O

V E

R Y

(R

Q D

B

LO

W C

O U

N T

S (N

V A

LU

E

BECC

360 Industrial Lane Birmingham AL Telephone: 2059411119

SC-SM

SC-SM

6.4

11.0

8.5

20.0

Groundwater encountered at 10'

Approximately 6.5" of CONCRETE

Loose, Brown Silty Clayey SAND

Very Loose, Brown Silty Clayey SAND

Very Stiff, Orange SIlty CLAY

Dense, Light Brown Clayey SAND

Very Stiff, Light Brown Silty CLAY

Medium Dense, Light Brown Gray SAND

Soil Boring terminated at 20.0 feet

SS

SS

SS

SS

SS

SS

40.7

43.3

4-3-2

(5)

4-2-2

(4)

4-6-10

(16)

11-17-18

(35)

6-9-10

(19)

5-5-7

(12)

HOLE DIAMETER 6 inches

GROUND ELEVATION

CONTRACTOR Geolab Environmental Drilling

REVIEWED BY R.Rhinehart

GEOLOGY Eocene Undifferentiated

BORING LOCATION See Map

BORING NUMBER B-2

PROJECT AFB Building 125 Renovation

LOGGED BY J.Mitchell

DATE COMPLETED 3/17/20

METHOD Hollow Stem Auger

BECC PROJECT NO. 319022

D E

P T

H (f t)

SPT N VALUE

20 40 60 80

BORING NUMBER - B-2

U N

IF

IE

D C

LA

S

S

IF

IC

A

T

IO

N

LI

Q

U

ID

LI

M

IT

G R

A P

H

IC

LO

G

M O

IS

T

U R

E C

O N

T E

N T

P

LA

S T

IC

IT

Y

IN

D E

X

NOTESMATERIAL DESCRIPTION

E

LE

V A

T

IO

N (f t)

S A

M P

LE

T

Y P

E N

U M

B E

R

F

IN

E S

C O

N T

E N

T

W A

T E

R

LE

V E

L

R E

C O

V E

R Y

(R

Q D

B

LO

W C

O U

N T

S (N

V A

LU

E

BECC

360 Industrial Lane Birmingham AL Telephone: 2059411119

GEOTECHNICAL LAB SUMMARY

Start Depth (ft.)

End Depth (ft.)

LL PL PI

B-1 1.0 2.5 30.5 6.6 17 16 1 --- --- --- --- --- SM

B-1 6.0 7.5 --- 11.5 --- --- --- --- --- --- --- --- ---

B-1 18.5 20.0 --- 16.9 --- --- --- --- --- --- --- --- ---

B-2 1.0 2.5 --- 6.4 --- --- --- --- --- --- --- --- ---

B-2 3.5 5.0 40.7 11.0 19 15 4 --- --- --- --- --- SM-SC

B-2 8.5 10.0 43.3 8.5 23 17 6 --- --- --- --- --- SM-SC

B-2 13.5 15.0 --- 20.0 --- --- --- --- --- --- --- --- ---

Sample

Boring Moisture (%) USCS D10 Grain size (mm)

D30 Grain Size (mm)

D60 Grain Size (mm)

Cu

Percent Passing

#200 Sieve

Robins AFB Building 125 Renovation 319022

Cz

Atterberg Limits

Project Name:

BECC Project No.:

APPENDIX C

Analytes Detected in Samples Analytes above Detectable Limits (DLs)

Robins AFB - Bldg 125 BECC Project #319022

Analyte Detection

(PPM)

Residential SL

(PPM)

Commercial SL

(PPM) Analyte Detection

(PPM)

Residential SL

(PPM)

Commercial SL

(PPM) Analyte Detection

(PPM)

Residential SL

(PPM)

Commercial SL

(PPM) Analyte Detection

(PPM)

Residential SL

(PPM)

Commercial SL

(PPM)

Barium 0.4 N/A 22000 Benzo(k)fluoranthene 0.060 N/A 210 Fluoranthene 0.056 N/A 3000 Acenaphthene 0.098 N/A 4500 Chrysene 0.067 N/A 2100 Phenanthrene 0.054 N/A N/A Anthracene 0.116 N/A 23000 Fluoranthene 0.138 N/A 3000 Pyrene 0.051 N/A N/A Benzo(a)anthracene 0.168 N/A 21 Phenanthrene 0.077 N/A N/A Benzo(b)fluoranthene 0.110 N/A 21 Pyrene 0.111 N/A N/A Benzo(k)fluoranthene 0.156 N/A 210 Benzo(a)pyrene 0.120 N/A 2.1 Chrysene 0.202 N/A 2100 Fluoranthene 0.535 N/A 3000 Fluorene 0.070 N/A 3000 Phenanthrene 0.448 N/A N/A

Pyrene 0.383 N/A N/A

=Exceeds Commercial SL NOTE: Bold items exceed applied SL =Exceeds Residential SL NOTE 2: EPA SLs applied using a Carcinogenic Target Risk (TR) of 1E-06 and Hazard Index (HI) of 0.10.

=Exceeds Both SLs

*EPA Regional SLs applied. Non-concer HI SLs were applied where the Carcinogenic TR SLs were not published.

^NOTE: Total chromium is a composite of Hexavalent Chromium (VI) and Chromium III, insoluble salts.

SL=Screening Level PPM=Parts Per Million

B2 0.5ft - 5ftB1 5ft - 10ftB1 0.5ft - 5ft B2 5ft - 10ft

APPENDIX D

LABORATORY ASSIGNMENT

Project Name: Date:

Project No.: Lab No.:

Sample No./Boring No.

Depth

D

(M o is tu re

D

(A tt er b er g)

C

/C

(S ie ve /W a sh

D

(W as h

D

/D

(P ro ct o r)

D

(C B

R

D

(S p ec ifi c G ra vi tiy

D

(S ie ve /H yd ro

D

(U n it W ei gh t)

B1 1-2.5

B1 6-7.5

B1 18.5-20

B2 1-2.5

B2 3.5-5

B2 8.5-10

B2 13.5-15

Assigned Started Completed

Robins AFB Building 125 Renovation

319022

3/23/2020

G205025

Remarks/Description

Corporate Office:

360 Industrial Ln.

Birmingham, AL 35211

Ph 205.941.1119 Fax 205.941.1198