Geotechnical Report TARC.pdf

GEOTECHNICAL ENGINEERING REPORT

DMA TARC VISITORS CENTER

111 SOUTH GEORGE MASON DRIVE

ARLINGTON, VIRGINIA

JOB NUMBER: 44634

PREPARED FOR:

MOSELEY ARCHITECTS

3200 NORFOLK STREET

RICHMOND, VIRGINIA 23230

February 28, 2020

TABLE OF CONTENTS

EXECUTIVE SUMMARY ............................................................................................. A

1. PROJECT INFORMATION

2. FIELD EXPLORATION

3. LABORATORY TESTING

Soil Index and Engineering Properties

Corrosion Series Testing

4. SITE GEOLOGY

5. SUBSURFACE CONDITIONS

Ground Surface Cover

Existing Fill Soils

Coastal Plain Soils

Groundwater

6. CONCLUSIONS AND RECOMMENDATIONS

Site Preparation

6.1.1 General

6.1.2 Subgrade Evaluation

6.1.3 Undercut Potential

6.1.4 Existing Utilities

Excavations

Re-use of On-site Soils as Structural Fill

Structural Fill

Permanent Cut and Fill Slopes

Foundations

Foundation Settlement

Seismic Site Classification

Slab-On-Grade

7. LIMITATIONS OF REPORT

8. CLOSURE

APPENDICES

Appendix A - Figures

Appendix B - Boring Logs

Appendix C - Laboratory Test Results

A

EXECUTIVE SUMMARY

For your convenience, this report is summarized in outline form below. This brief summary should not be used for design or construction purposes without reviewing the more detailed conclusions and recommendations contained in this report.

1. The subsurface exploration included a visual site reconnaissance, performance of four (4) test borings to a depth of 20 feet below the ground surface, and soil laboratory testing.

2. The borings encountered approximately 2 to 3 inches of topsoil material. Existing fill material was encountered below the topsoil to depths of 2 to 4 feet. Underlying the topsoil and fill soils, undisturbed coastal plain soils were encountered to the boring termination depth. Groundwater was encountered in the borings at depths ranging from 14.2 to 18 feet below current grades.

3. Near-surface soils were measured to be of low to moderate plasticity and are likely to be moisture sensitive. As such, we recommend that site grading be conducted during the typically warmer summer months, if possible.

4. Existing fill soils which were of varying degrees of compaction were encountered in the borings.

Repair of subgrade soils (i.e., undercutting and replacement) may be required, and repair depths could be on the order of 24 to 48 inches below the existing ground surface. It is also expected that these fill soils will be relatively wet and may be difficult to properly dry prior to re-use.

5. Where fill is present in building slab-on-grade and concrete sidewalk areas, the fill should be evaluated with test pit excavations and proofrolling in the presence of the geotechnical engineer to determine if the fill characteristics are suitable to support these elements. Excessively debris-laden or organic-laden materials should be undercut and replaced with suitable well-compacted fill materials.

6. On-site low to moderate plasticity soils, excluding topsoil and debris-laden soils, should be suitable for re-use as structural fill, provided the moisture content can be properly controlled.

7. The proposed structure may be supported on shallow foundations designed using an allowable bearing pressure of 2,000 psf. Foundations should bear at least 24 inches below finished building pad soil subgrade. Existing fill is not considered suitable for foundation support. Over-excavation and replacement (with VDOT No. 57 stone) of existing fill soils or soft bearing soils will be required below all foundations. Based on our field exploration and analysis, settlement of foundations is expected to be 1 inch or less.

8. Relatively high sulfate levels were encountered during our laboratory testing of soil. As such, consideration should be given to providing near-surface and below grade concrete capable of resisting high sulfate levels (i.e. with Type V Portland cement).

9. We recommend the site be considered Seismic Site Classification E based on the 2015 edition of the International Building Code.

10. If actual structural loading and proposed grades differ from those assumed in this report, we must be contacted to confirm or modify the recommendations of this report.

1001 Boulders Parkway

Suite 300

Arlington, VA 23225

P 804.200.6500

F 804.560.1016 www.timmons.com

February 28, 2020

Mosely Architects

3200 Norfolk Street

Richmond, Virginia 23230

Attention: Mr. Tony Bell

Re: Geotechnical Engineering Report

DMA TARC Visitors Center

111 South George Mason Drive

Arlington, Virginia

Timmons Group Project No. 44634

Mr. Bell:

Timmons Group is pleased to submit this geotechnical engineering report for the referenced project. The objectives of our services were to explore subsurface conditions and provide our geotechnical recommendations for site grading and foundation support.

1. PROJECT INFORMATION

The project site is located on the campus of the existing Army National Guard Readiness Center, located at 111 South George Mason Drive in Arlington, Virginia. Specifically, the site is bordered by South George Mason Drive to the west, an existing guard shack and security entrance to the north, an existing parking garage to the south, and an asphalt paved roadway to the east. The project site generally consists of an open grass covered lot with an asphalt walkway traversing the site, as well several trees, landscaped areas, and bollards along a portion of the perimeter. A Site Vicinity

Map is shown on Figure 1 in Appendix A.

The proposed development at this site is expected to consist of a new one-story structure, roughly

3,200 square feet in plan area, as well as concrete sidewalks and landscaped green areas. Structural loading conditions were not available at the time of this report. However, based on our experience with similar projects, we have assumed maximum column and wall loads of 150 kips and 3 kips per linear foot, respectively. First floor slabs are expected to be supported on-grade.

The existing grades at this site range from approximately 218 to 220 feet MSL, and the finished floor elevation (FFE) of the proposed structure is expected to be 220 feet MSL. As such, we expect cuts and fills to be minimal.

Geotechnical Engineering Report Project No. 44634

DMA TARC Visitors Center - Arlington, VA February 28, 2020

2. FIELD EXPLORATION

The field exploration included a visual site reconnaissance by a representative of Timmons Group, and performance of four (4) soil test borings (B-1 through B-4). A representative of Timmons

Group established boring locations in the field by measuring from existing landmarks.

Approximate boring locations are shown on Figure 2 in Appendix A.

Borings were performed to a depth of approximately 20 feet below the existing ground surface with hollow stem auger drilling techniques. Split-spoon samples of subsurface soils were taken within soil test borings at approximate 2-foot intervals above a depth of 10 feet and at 5-foot intervals below 10 feet. Standard Penetration Tests (SPT) were conducted in conjunction with split-spoon sampling in general accordance with ASTM D 1586-99.

Water levels were measured in open boreholes at the time of drilling. Upon completion, boreholes were backfilled with drill cuttings to match the existing ground surface. Representative portions of split-spoon soil samples were returned to our laboratory for quantitative testing and visual classification in general accordance with Unified Soil Classification System guidelines.

Boring logs and a generalized soil profile (Figure 3), which present specific information from the borings, are included in the Appendices. Stratification lines shown on the logs and profile are intended to represent approximate depths of changes in soil types. Naturally, transitional changes in soil types are often gradual and cannot be defined at particular depths. Ground surface elevations shown on these documents were interpolated from a site topographic survey and should be considered approximate.

3. LABORATORY TESTING

Laboratory testing was performed on representative split-spoon and bulk soil samples obtained from the borings. This testing consisted of natural moisture content, Atterberg limits, grain size analysis, Standard Proctor, and California Bearing Ratio (CBR) testing which were performed in general accordance with applicable ASTM procedures. Chemical analyses of soil samples (pH, chlorides, electrical resistivity, oxidation-reduction potential, sulfides, and sulfates) were also performed. Individual laboratory test data sheets are provided in Appendix C. A summary of laboratory test data is provided in the tables below.

Soil Index and Engineering Properties

The following tables provide a summary of natural moisture content, Atterberg limits, grain size analyses, Standard Proctor, and California Bearing Ratio (CBR) test data on representative soils from the site.

Natural Moisture and Classification Tests

Boring Depth

(ft.)

Natural

Moisture

Content (%)

Atterberg Limits Grain Size Analysis

USCS

Classification LL PL PI % Fines* % Sand % Gravel

B-1 0.5-4 25.3 45 19 26 42.0 56.1 1.9 SC

B-2 2-4 16.2 NT NT NT NT NT NT CL

B-3 0-2 16.9 NT NT NT NT NT NT CL

B-4 13.5-15 35.3 41 26 15 39.4 60.6 0.0 SM

*Material passing No. 200 sieve (clay and silt), NT = Not Tested

Standard Proctor and CBR Testing

Boring Depth

(ft.)

Natural

Moisture

Content (%)

Standard Proctor

CBR

Swell

USCS

Classification Optimum Moisture

Content (%) Maximum Dry

Density (pcf)

B-1 0.5-4 25.3 13.0 113.0 6.1 1.8 SC

Based on the visual classifications and Atterberg limits testing, the near-surface soils are of low to moderate plasticity. Based on comparison of natural moisture contents to the optimum moisture content of the bulk sample, near-surface soils appear wet of optimum moisture. Drying of near-surface soils should be anticipated prior to their re-use as fill. The time of year grading occurs will likely have a significant impact on the moisture levels of near-surface soils.

Corrosion Series Testing

As shown in the table below, the pH levels obtained from near-surface soils are slightly acidic.

The measured results (pH, chlorides, electrical resistivity, oxidation-reduction potential, laboratory resistivity, and field resistivity) should be evaluated with respect to the appropriate level of protection determined by the design engineer. Sulfate contents appear moderately high. From our understanding, sulfates levels above 150 mg/kg present the potential for aggressive attack on concrete. As such, consideration should be given to providing near-surface and below grade concrete capable of resisting high sulfate levels (i.e. with Type V Portland cement).

Corrosion Series Testing

Boring Depth

(Feet)

Chlorides

(mg/kg) pH

Laboratory Electrical

Resistivity (ohm-cm)

Oxidation Reduction

Potential (mV)

Sulfates

(mg/kg)

Sulfides

(mg/kg)

B-1 0.5-4 15.5 6.3 2,060 280.3 179 Trace

4. SITE GEOLOGY

According to the 1993 Geologic Map of Virginia, the project site is located in the Coastal Plain

Physiographic Province. The coastal plain is characterized by unconsolidated marine to fluvial sediments, varying from clay to gravel, poorly to well sorted, with lateral variation in thickness, although generally increasing in thickness towards the east. Vertical variation within the geologic formations of the coastal plain is often controlled by cyclic sequences that fine or coarsen with depth, with formations separated by unconformities. Regionally, the stratigraphy of the coastal plain can be generalized as a wedge of sediments composed of fluvial and coastal plain sands and gravels of Quaternary and upper Tertiary age, underlain by marine, deltaic, and fluvial clays, silts, and sands of lower Tertiary age, underlain by fluvial-deltaic to shallow-shelf sands and clays of

Cretaceous age, underlain by crystalline bedrock. Depth to bedrock varies from tens of feet near the western extent of the coastal plain at the Fall Line (approximate Interstate I-95 corridor) to over 2,000 feet near the Atlantic coastline.

Based on review of the 1993 Geologic Map of Virginia, the site is located within the Potomac

Formation. This Formation is described as pebbly poorly sorted quartzo-feldspathic Sand interbedded with Sandy Clay and Silt.

5. SUBSURFACE CONDITIONS

The following is a summary of subsurface conditions encountered during the exploration.

Ground Surface Cover

Ground surface cover at the boring locations consisted of approximately 2 to 3 inches of surficial topsoil material. The topsoil thickness may vary across the site.

Existing Fill Soils

Beneath the ground surface cover, existing fill soils were encountered in the borings to depths of approximately 2 to 4 feet below the ground surface. The fill consisted of very loose to medium dense Clayey SAND (SC), and medium stiff lean CLAY (CL) with varying amounts of Gravel, roots, and construction debris. The Standard Penetration Test (SPT) N-values encountered within the fill ranged from 4 to 10 blows per foot (bpf). Based on past experience, well-compacted fill soils should exhibit SPT N-values of at least 8 bpf, indicating that the encountered fill appears to be of varying degrees of compaction.

Coastal Plain Soils

Beneath the topsoil and fill materials, undisturbed coastal plain soils were encountered to the boring termination depth of 20 feet below the ground surface. These soils consisted of very loose to medium dense Silty and Clayey SAND (SM, SC), and medium stiff lean CLAY (CL). Varying amounts of Gravel and mica were encountered within these soils. SPT N-values within the soil profile ranged from 2 to 15 blows per foot (bpf).

Groundwater

At the time of exploration, groundwater was encountered in the borings at depths ranging from

14.2 to 18 feet below the ground surface. It is important to realize that groundwater levels will fluctuate with changes in rainfall and evaporation rates. In addition, perched groundwater could be encountered within near-surface soils, particularly after rainfall.

6. CONCLUSIONS AND RECOMMENDATIONS

Our geotechnical conclusions and recommendations for the proposed site development are presented in the following sections. If subsurface conditions adverse to those indicated by this report are encountered during construction, those differences should be reported to us for review and comment. The following conclusions and recommendations are based upon our borings, laboratory testing, engineering analysis, and past experience with similar projects and subsurface conditions. If the assumed structural loads or future site grades differ from those assumed, we must be contacted to confirm or revise the recommendations of this report.

When reviewing our recommendations, it is important to note that prior grading activities have occurred at this site. Based on our past experience with previously graded sites, unexpected subsurface conditions are often encountered. These conditions could include zones of low-consistency fill, debris-laden materials, abandoned utilities, and other unexpected conditions.

These conditions, if encountered, can be addressed by on-site engineering evaluation at the time of construction.

Again, relatively high sulfate levels were encountered during our laboratory testing. As such, consideration should be given to providing near-surface and below grade concrete capable of resisting high sulfate levels (i.e. with Type V Portland cement).

Site Preparation

6.1.1 General

Site grading will be difficult during periods of extended rainfall and low temperatures that generally occur during the winter and early spring months. Near-surface soils consist of fine-grained clays and sands with considerable fines content that are very moisture sensitive. If grading is conducted during a wet time period, soils will tend to rut and pump under rubber-tired traffic and provide poor subgrade support for concrete sidewalks and the building slab-on-grade. Heavy rubber-tired construction equipment should not be allowed to operate on wet or unstable subgrades at this site due to the potential for rutting and other damage to the soils. To reduce potential earthwork problems, site preparation and grading should be scheduled during the typically warmer summer months, if possible. We recommend that exposed subgrades be sloped and sealed at the end of each day to promote runoff and reduce infiltration from rainfall.

Site preparation should begin with demolition and removal of existing asphalt walkway, clearing and grubbing of existing trees, stripping of topsoil, and removal of any other unsuitable materials.

Approximately 2 to 3 inches of topsoil material was encountered in the borings. The topsoil depth is expected to vary across the site and should be expected to extend deeper in some areas. Also, stripping activities often mix topsoil with underlying “clean” soils and cause stripping depths to be greater than actual topsoil depths, particularly during wet periods of the year. Asphalt, topsoil, and vegetation should be wasted from the site or permanently stockpiled outside of the proposed construction limits.

6.1.2 Subgrade Evaluation

After demolition and removal of existing asphalt walkway, clearing and grubbing of trees, and stripping of topsoil, soil subgrades to receive fill and finished subgrades should be evaluated by the Geotechnical Engineer or his representative. To aid the engineer during this evaluation, exposed soil subgrades should be proofrolled with a loaded tandem axle dump truck or equivalent.

Proofrolling will help to reveal the presence of unstable or otherwise unsuitable surface materials.

The following methods are typically used to repair soil subgrades that are observed to rut, pump, or deflect excessively during proofrolling:

• Undercut the unstable soils to firm soils and replace them with suitable, well compacted fill.

• In-place repair of near-surface soils by scarifying, drying and re-compacting, when weather conditions are suitable.

6.1.3 Undercut Potential

The borings encountered existing fill soils which were of varying degrees of compaction. We expect that repair of the upper 24 to 48 inches of soils will be required in portions of the site. In addition, the surficial fill soils are expected to be relatively wet and require drying prior to their re-use as structural fill (if suitable).

Our experience is that existing fill soils can be highly variable in stiffness and material characteristics. Over-excavation and replacement of fill below building foundations will be required, as discussed in the Building Foundations section of this report. Where fill is present in building slab-on-grade and concrete sidewalk areas, the fill should be evaluated with test pit excavations and proofrolling in the presence of the geotechnical engineer to determine if the fill characteristics are suitable to support these elements. Excessively debris-laden or organic-laden materials should be undercut and replaced with suitable well-compacted fill materials.

6.1.4 Existing Utilities

During our field exploration, the presence of below-grade utilities was detected within the vicinity of the proposed building footprint. We recommend that any existing underground utilities be relocated outside the proposed building footprint. Abandoned utilities should be removed from the site. Past experience indicates that poorly compacted fill soils are often located within utility trenches. For utilities that are to be removed, we recommend that trenches be cleaned of all backfill soils and backfilled with structural fill compacted to levels recommended in this report. If certain utility lines must remain in place in their current location, we recommend that the suitability of trench backfill be evaluated on a case-by-case basis.

Excavations

We expect that excavations will extend through low to moderate consistency soils. Past experience indicates that these consistency soils can be excavated by routine earth moving equipment.

Soil types with respect to trench safety must be evaluated on a case-by-case basis. The Contractor should be responsible for all site safety, including the determination of appropriate trench safety measures according to OSHA guidelines.

Water was encountered in the borings at depths ranging from 14.2 to 18 feet below existing grades, which is below the anticipated maximum excavation depth. However, shallow perched groundwater could be present within near-surface soils, particularly after rainfall events. The contractor should be prepared to control and remove groundwater seepage that occurs within excavations.

Re-use of On-site Soils as Structural Fill

Low to moderate plasticity soils encountered in the borings, excluding topsoil or debris-laden soils, should be suitable for re-use as structural fill, provided the moisture content can be properly controlled. However, some of the near-surface soils appear wet and will likely require drying if they prove to be wet of optimum moisture and therefore unable to achieve the appropriate degree of compaction at their current moisture levels.

Prevailing weather conditions will have a significant impact on the amount of moisture manipulation (i.e. drying or wetting) required prior to fill placement. At the time of our exploration, near-surface soils typically appeared wet of optimum moisture.

Structural Fill

On-site soils used as structural fill in building and sidewalk areas should be free of debris, contain less than 5 percent organics, have a liquid limit (LL) less than 45, have plasticity index (PI) less than 20, and have a maximum particle size of 3 inches. Imported soil should be free of debris, contain less than 5 percent organics, have a LL less than 35, and have a PI less than 15. Structural fill should be placed in maximum 8 to 10-inch loose lifts and compacted to at least 95 percent of the Standard Proctor maximum dry density (ASTM D 698). The final 12 inches of structural fill relative to finished subgrade should be compacted to at least 98 percent of the Standard Proctor maximum dry density. Structural fill should be maintained within 2 percentage points of optimum moisture during placement and compaction.

Site preparation, including fill placement and compaction, should be observed by a qualified soils technician working under the direction of the Geotechnical Engineer. During fill placement, a sufficient amount of in-place density tests should be conducted to confirm that compaction and fill moisture is in accordance with our recommendations.

Permanent Cut and Fill Slopes

Permanent cut and fill slopes should inclinations no steeper than 3(H):1(V) for long term stability and erosion control. Localized zones of perched groundwater may be present within the near surface soils following periods of rainfall. If seepage is observed along permanent cut slopes, flattening of the slope angle, installation of a toe drain or other measures may be required to improve long-term stability.

Based on our experience, compaction equipment often has difficulty compacting soils along the faces of fill slopes. As such, we recommend that fill slopes be slightly overbuilt and then cut back to the design geometry, leaving the slope face compacted to the required degree.

Foundations

For the purposes of our engineering analysis, we assumed that the maximum column and wall loads for the proposed structure will be 150 kips and 3 kips per linear foot, respectively. Based on the assumed loading, the borings, laboratory testing, and our engineering analysis, the proposed structure may be supported on shallow foundations bearing in stiff, undisturbed soils or well-compacted fill overlying stiff, undisturbed soils. Shallow foundations may be designed using an allowable bearing pressure of 2,000 psf. Footings should bear at least 24 inches below finished building pad soil subgrade for frost protection, and to develop the required bearing capacity.

Individual column and wall foundations should have a minimum width of 24 inches and 18 inches, respectively. Again, relatively high sulfate levels were encountered during our laboratory testing.

As such, consideration should be given to providing near-surface and below grade concrete capable of resisting high sulfate levels (i.e. with Type V Portland cement).

Existing fill is not considered suitable for support of foundations. Existing fill and any soft/loose, undisturbed soils should be removed and replaced beneath foundations. Foundation excavations should be evaluated by the Geotechnical Engineer or his representative prior to reinforcing steel and concrete placement. The evaluation should involve probing of foundation bearing surfaces, advancing shallow hand auger borings, and Dynamic Cone Penetrometer (DCP) testing. Where loose/soft soils or existing fill are present at bearing elevations, neat-line over-excavation and replacement of foundation bearing soils with VDOT No. 57 stone will be required.

If groundwater or surface water runoff collects in any excavation, it should be removed promptly.

Care should be exercised during construction of foundations in order not to disturb bearing soils and reduce their bearing strength. Concrete for the footings should be placed as soon as practical following excavation.

Foundation Settlement

Based on the assumed structural loads and our analysis, we expect that total foundation settlements for the proposed structure will be one inch or less, provided that foundations are constructed in accordance with the recommendations presented in this report. Differential settlements should be less should be less than ½ inches for footings bearing on similar materials.

Seismic Site Classification

Based on our test borings and our past experience, it is our opinion the site should be considered

Seismic Site Classification E in accordance with the 2015 edition of the International Building

Code (IBC).

Slab-On-Grade

The slab-on-grade can be adequately supported on approved in-place soils or new structural fill, provided the site preparation and fill placement procedures outlined in this report are implemented.

It is our opinion that a modulus of subgrade reaction of 100 pci is applicable for slab-on-grade design. We recommend the slabs-on-grade be separated from building foundations to allow for relative displacement.

In addition, we recommend that a minimum of 6 inches of VDOT 21B stone be considered for placement beneath concrete slabs to provide an all-weather construction surface and greater uniformity in slab subgrade support. We recommend that the stone be compacted to at least 98 percent of its Standard Proctor maximum dry density (ASTM D 698).

Exposure to the environment and construction activities will weaken the floor slab subgrade soils.

Therefore, we recommend that subgrade soils in slab areas be evaluated prior to aggregate base material placement. If deterioration of soils has occurred, undercutting may be necessary.

APPENDIX A

FIGURES

FIGURE

SITE VICINITY MAP

DMA TARC VISITORS CENTER

111 SOUTH GEORGE MASON DRIVE

ARLINGTON, VA

SCALE:

PLOTTED BY:

DATE:

NTS

CHECKED BY: JNR

JRR

1-13-20 PROJECT NUMBER: 44634

Source: Google Earth

NORTHNORTH

APPROXIMATE

SITE LOCATION

FIGURE

BORING LOCATION PLAN

DMA TARC VISITORS CENTER

111 SOUTH GEORGE MASON DRIVE

ARLINGTON, VA

SCALE:

PLOTTED BY:

DATE:

NTS

CHECKED BY: JNR

JRR

1-13-20 PROJECT NUMBER: 44634

Source: Timmons Group, Site Plan, February 19, 2020 = APPROXIMATE LOCATION OF TEST BORING

NORTHNORTH

South George Mason Drive

Existing Parking Garage

B-1 B-3

B-2 B-4

APPENDIX B

BORING LOGS

SANDS WITH

FINES

LIQUID LIMIT

LESS THAN 50

LIQUID LIMIT

GREATER THAN 50

HIGHLY ORGANIC SOILS

NOTE: DUAL SYMBOLS ARE USED TO INDICATE BORDERLINE SOIL CLASSIFICATIONS

GW

GP

GM

GC

SW

SP

SM

SC

ML

CL

OL

MH

CH

OH

PT

GRAVEL

AND

GRAVELLY

SOILS

CLAYEY GRAVELS, GRAVEL - SAND -

CLAY MIXTURES

WELL-GRADED SANDS, GRAVELLY

SANDS, LITTLE OR NO FINES

POORLY-GRADED SANDS,

GRAVELLY SAND, LITTLE OR NO

FINES

SILTY SANDS, SAND - SILT

MIXTURES

CLAYEY SANDS, SAND - CLAY

MIXTURES

INORGANIC SILTS AND VERY FINE

SANDS, ROCK FLOUR, SILTY OR

CLAYEY FINE SANDS OR CLAYEY

SILTS WITH SLIGHT PLASTICITY

INORGANIC CLAYS OF LOW TO

MEDIUM PLASTICITY, GRAVELLY

CLAYS, SANDY CLAYS, SILTY

CLAYS, LEAN CLAYS

ORGANIC SILTS AND ORGANIC

SILTY CLAYS OF LOW PLASTICITY

INORGANIC SILTS, MICACEOUS OR

DIATOMACEOUS FINE SAND OR

SILTY SOILS

INORGANIC CLAYS OF HIGH

PLASTICITY

SILTS

AND

CLAYS

MORE THAN 50%

OF MATERIAL IS

LARGER THAN

NO. 200 SIEVE

SIZE

MORE THAN 50%

OF MATERIAL IS

SMALLER THAN

NO. 200 SIEVE

SIZE

MORE THAN 50%

OF COARSE

FRACTION

PASSING ON NO.

4 SIEVE

MORE THAN 50%

OF COARSE

FRACTION

RETAINED ON NO.

4 SIEVE

SOIL CLASSIFICATION CHART

(APPRECIABLE

AMOUNT OF FINES)

(APPRECIABLE

AMOUNT OF FINES)

(LITTLE OR NO FINES)

FINE

GRAINED

SOILS

SAND

AND

SANDY

SOILS

SILTS

AND

CLAYS

ORGANIC CLAYS OF MEDIUM TO

HIGH PLASTICITY, ORGANIC SILTS

PEAT, HUMUS, SWAMP SOILS WITH

HIGH ORGANIC CONTENTS

LETTERGRAPH

SYMBOLS

MAJOR DIVISIONS

COARSE

GRAINED

SOILS

TYPICAL

DESCRIPTIONS

WELL-GRADED GRAVELS, GRAVEL -

SAND MIXTURES, LITTLE OR NO

FINES

POORLY-GRADED GRAVELS,

GRAVEL - SAND MIXTURES, LITTLE

OR NO FINES

SILTY GRAVELS, GRAVEL - SAND -

SILT MIXTURES

CLEAN

GRAVELS

GRAVELS WITH

FINES

CLEAN SANDS

(LITTLE OR NO FINES)

KEY TO BORING LOG TERMINOLOGY

Relative Density – Used for soils with less than 50% passing No. 200 sieve

Consistency – Used for soils with 50 percent or more passing No. 200 sieve

Relative Density SPT N-Value

(blows/ft) Consistency

SPT N-Value (blows/foot)

Very Loose 0 to 3 Very Soft 0 to 1 Loose 4 to 9 Soft 2 to 4

Medium Dense 10 to 29 Firm 5 to 8 Dense 30 to 50 Stiff 9 to 15

Very Dense Greater than 50 Very Stiff 16 to 30 Hard 31 to 50 Very Hard Greater than 50

Grain Size Terminology (U.S. Standard Sieves) Natural Moisture Content

Term Particle Size Boulder 12 inches +

Dry Very little apparent moisture, dusty Cobble 3 to 12 inches Coarse Gravel ¾ to 3 inches

Moist Damp, but no free water visible Fine Gravel #4 to ¾ inches Coarse Sand #10 to #4 Medium Sand #40 to #10

Wet Visible free water, or in cohesive soil, clearly saturated Fine Sand #200 to #40

Silt and Clay <#200

2-inches Topsoil CLAYEY SAND, (SC): orangeish gray, fine to coarse grained, moist, loose, trace fine gravel, trace roots, "FILL"

SANDY LEAN CLAY, (CL): light orangeish gray, moist, medium stiff

SILTY SAND, (SM): light reddish gray, fine to medium grained, moist to wet, very loose to loose

Bottom of borehole at 20.0 feet.

S-1, SPT

1-4-6-6

(10)

S-2, SPT

3-4-5-8

(9)

S-3, SPT

2-2-4-6

(6)

S-4, SPT

3-4-4-7

(8)

S-5, SPT

2-3-5-10

(8)

S-6, SPT

2-1-4-8

(5)

S-7, SPT

1-2-2-3

(4)

E

LE

V A

T

IO

N (f t)

LAB TESTS

D E

P T

H (f t)

S Y

M B

O L

MATERIAL DESCRIPTION REMARKS

R E

C O

V E

R Y

)SAMPLING

BLOW COUNTS

(N-VALUE)

BORING B-1

GROUND ELEVATION 218.5 ft

LOGGED BY J. Robinson, P.E.

DRILLING CONTRACTOR Shenandoah Drilling, Inc.

CHECKED BY N. Reeves, P.E.

HOLE DEPTH 20 feet

BOREHOLE WATER LEVELS:

NOTES

AT 24 HOURS DRILLING ---

AT END OF DRILLING 14.20 ft / Elev 204.30 ftDRILLING METHOD Hollow Stem Auger

DATE STARTED 1/13/2020 COMPLETED 1/13/2020

CAVE DEPTH

PROJECT NAME DMA TARC Visitor Center

PROJECT LOCATION Arlington, Virginia

PROJECT NUMBER 44634

CLIENT Moseley Architects

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\D M

A T

A R

C V

IS

IT

O R

C E

N T

E R

.G P

J Timmons Group 1001 Boulders Parkway, Suite 300 Richmond, VA 23225 Telephone: (804) 200-6500

SANDY LEAN CLAY, (CL): orangeish gray, moist, medium stiff, trace fine gravel, trace roots, trace construction debris, "FILL"

CLAYEY SAND, (SC): orangeish gray, fine to coarse grained, moist, loose, trace fine gravel

SILTY SAND, (SM): orangeish gray, fine to coarse grained, moist to wet, very loose to loose

Bottom of borehole at 20.0 feet.

S-1, SPT

1-3-4-17

(7)

S-2, SPT

2-3-4-9

(7)

S-3, SPT

2-1-4-5

(5)

S-4, SPT

5-4-4-7

(8)

S-5, SPT

2-2-5-8

(7)

S-6, SPT

3-2-4-6

(6)

S-7, SPT

2-1-1-4

(2)

E

LE

V A

T

IO

N (f t)

LAB TESTS

D E

P T

H (f t)

S Y

M B

O L

MATERIAL DESCRIPTION REMARKS

R E

C O

V E

R Y

)SAMPLING

BLOW COUNTS

(N-VALUE)

BORING B-2

GROUND ELEVATION 219.5 ft

LOGGED BY J. Robinson, P.E.

DRILLING CONTRACTOR Shenandoah Drilling, Inc.

CHECKED BY N. Reeves, P.E.

HOLE DEPTH 20 feet

BOREHOLE WATER LEVELS:

NOTES

AT 24 HOURS DRILLING ---

AT END OF DRILLING 17.00 ft / Elev 202.50 ftDRILLING METHOD Hollow Stem Auger

DATE STARTED 1/13/2020 COMPLETED 1/13/2020

CAVE DEPTH

PROJECT NAME DMA TARC Visitor Center

PROJECT LOCATION Arlington, Virginia

PROJECT NUMBER 44634

CLIENT Moseley Architects

T G

G E

O T

E C

H B

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V 2.

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T S

T D

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L A

B .G

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/1

/2

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\G

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C H

N

IC

A L\

P R

O

JE

C T

S \2

P R

O

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C T

S \4

D M

A T

A R

C V

IS

IT

O R

C E

N T

E R

\L O

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\D M

A T

A R

C V

IS

IT

O R

C E

N T

E R

.G P

J Timmons Group 1001 Boulders Parkway, Suite 300 coarse grained, moist, very loose to loose, trace fine gravel, trace roots, trace construction debris, "FILL"

SILTY SAND, (SM): orangeish gray, fine to coarse grained, moist, medium dense, with fine to coarse gravel

CLAYEY SAND, (SC): orangeish gray, fine to coarse grained, moist, loose

SILTY SAND, (SM): orangeish gray, fine to medium grained, moist to wet, loose

Bottom of borehole at 20.0 feet.

S-1, SPT

1-2-2-4

(4)

S-2, SPT

3-3-2-4

(5)

S-3, SPT

3-4-7-9

(11)

S-4, SPT

5-5-7-10

(12)

S-5, SPT

2-2-5-7

(7)

S-6, SPT

3-3-4-8

(7)

S-7, SPT

2-2-3-5

(5)

E

LE

V A

T

IO

N (f t)

LAB TESTS

D E

P T

H (f t)

S Y

M B

O L

MATERIAL DESCRIPTION REMARKS

R E

C O

V E

R Y

)SAMPLING

BLOW COUNTS

(N-VALUE)

BORING B-3

GROUND ELEVATION 218 ft

LOGGED BY J. Robinson, P.E.

DRILLING CONTRACTOR Shenandoah Drilling, Inc.

CHECKED BY N. Reeves, P.E.

HOLE DEPTH 20 feet

BOREHOLE WATER LEVELS:

NOTES

AT 24 HOURS DRILLING ---

AT END OF DRILLING 16.50 ft / Elev 201.50 ftDRILLING METHOD Hollow Stem Auger

DATE STARTED 1/13/2020 COMPLETED 1/13/2020

CAVE DEPTH

PROJECT NAME DMA TARC Visitor Center

PROJECT LOCATION Arlington, Virginia

PROJECT NUMBER 44634

CLIENT Moseley Architects

T G

G E

O T

E C

H B

H L

O G

V 2.

G

IN

T S

T D

U S

L A

B .G

D T

/1

/2

3:

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\G

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C H

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IC

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P R

O

JE

C T

S \2

P R

O

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C T

S \4

D M

A T

A R

C V

IS

IT

O R

C E

N T

E R

\L O

G S

\D M

A T

A R

C V

IS

IT

O R

C E

N T

E R

.G P

J Timmons Group 1001 Boulders Parkway, Suite 300

3-inches Topsoil coarse grained, moist, loose, trace fine gravel, trace roots, trace construction debris, "FILL" SILTY SAND, (SM): orangeish gray, fine to coarse grained, moist, medium dense, trace mica SILTY SAND, (SM): orangeish gray, fine to coarse grained, moist, medium dense, with fine to coarse gravel CLAYEY SAND, (SC): orangeish gray, fine to coarse grained, moist, medium dense, trace fine gravel SANDY LEAN CLAY, (CL): light orangeish gray, moist, medium stiff, trace fine gravel

SILTY SAND, (SM): orangeish gray, fine to medium grained, moist to wet, very loose

Bottom of borehole at 20.0 feet.

S-1, SPT

2-2-3-7

(5)

S-2, SPT

4-6-9-11

(15)

S-3, SPT

3-4-7-8

(11)

S-4, SPT

5-5-7-8

(12)

S-5, SPT

1-3-3-5

(6)

S-6, SPT

3-1-3-5

(4)

S-7, SPT

2-1-2-4

(3)

E

LE

V A

T

IO

N (f t)

LAB TESTS

D E

P T

H (f t)

S Y

M B

O L

MATERIAL DESCRIPTION REMARKS

R E

C O

V E

R Y

)SAMPLING

BLOW COUNTS

(N-VALUE)

BORING B-4

GROUND ELEVATION 219.5 ft

LOGGED BY J. Robinson, P.E.

DRILLING CONTRACTOR Shenandoah Drilling, Inc.

CHECKED BY N. Reeves, P.E.

HOLE DEPTH 20 feet

BOREHOLE WATER LEVELS:

NOTES

AT 24 HOURS DRILLING ---

AT END OF DRILLING 18.00 ft / Elev 201.50 ftDRILLING METHOD Hollow Stem Auger

DATE STARTED 1/13/2020 COMPLETED 1/13/2020

CAVE DEPTH

PROJECT NAME DMA TARC Visitor Center

PROJECT LOCATION Arlington, Virginia

PROJECT NUMBER 44634

CLIENT Moseley Architects

T G

G E

O T

E C

H B

H L

O G

V 2.

G

IN

T S

T D

U S

L A

B .G

D T

/1

/2

3:

Y :\8

\G

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T E

C H

N

IC

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P R

O

JE

C T

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P R

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S \4

D M

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\L O

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\D M

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J Timmons Group 1001 Boulders Parkway, Suite 300

APPENDIX C

LABORATORY TEST RESULTS

Form No. TR-Moisture Content

Revision No. 0.1

Revision Date: 5/18/18

Project #: 44634 Report Date:

Project Name: DMA TARC Visitor Center Test Date(s):

Project Location: Arlington, Virginia Tested By: MLT and KP

Client Name: Moseley Architects

Sampled By: Shenandoah Drilling, Inc. Sample Date(s): 1/13/2020

Sampling Method: Split Barrel & Bulk Samples

Lab Number: 2780 2781 2782 2783

Sample Locaton: B-01* B-02 B-03 B-04

Sample Number: Bulk S-2 S-1 S-6

Sample Depth (ft): 0.5 to 4 2 to 4 0 to 2 13.5 to 15

Tare Number: 2G T216 2E 801

Tare Weight (g): 15.8 13.7 13.1 127.8

Wet Soil + Tare (g): 284.8 266 249.4 258.9

Dry Soil + Tare (g): 230.4 230.8 215.2 224.7

Water Weight (g): 54.4 35.2 34.2 34.2

Dry Soil Weight (g): 214.6 217.1 202.1 96.9

Water Content (%): 25.3 16.2 16.9 35.3

USCS (ASTM D 2487): SC *CL *CL SM

Approx. Max Grain Size: 3/8" 3/8" 3/4" No. 10

Mass Less Than Minimum? Yes Yes Yes Yes

More than One Material? No No No No

Alternate Oven Temperature: --- --- --- ---

Describe Excluded Material: --- --- --- ---

References / Comments / Deviations:

*ASTM D2488 Standard Practice for Description and Identification of Soils (Visual-Manual Procedure)

*Moisture content of auger cuttings collected as bulk material is not representative of subgrade conditions at the time of drilling.

Matthew Thornton Laboratory Manager 2/7/20 Date

OF WATER CONTENT

LABORATORY DETERMINATION

PROJECT INFORMATION

ASTM D 2216 Method B

1/27/20 to 1/28/20

2/7/2020

Technical Responsibility Signature Position

SAMPLE INFORMATION

This report shall not be reproduced, except in full, without the written approval of Timmons Group

Information included in this report relates only to material sampled at the time of testing.

Timmons Group 430 Southlake Boulevard Suite B‐15

Richmond, VA 23236

44634 Soil Lab Database

Form No. TR-GSA

Revision No. 1.1

Revision Date: 05/18/18

Report Date:

DMA TARC Visitor Center Test Date(s):

Tested By:

Sample #: Sample Date:

Depth:

Description of Sand & Gravel Particles: Rounded x Angular x Hard and Durable x Soft Weathered and Friable

References / Comments / Deviations:

*Moisture content of auger cuttings collected as bulk material is not representative of subgrade conditions at the time of drilling.

MLT and KP

Information included in this report relates only to material sampled at the time of testing.

SAMPLE INFORMATION

Moseley Architects

B-01 BulkLocation:

Fine SandCobbles < 300 mm (12") and > 75 mm (3")

Material Description:

1/13/2020

0.5 to 4 feet Offset: N/A Lab Control #: 2780

Grain Size Analysis

ASTM D422

PROJECT INFORMATION

2/7/2020 1/27/20 to 2/4/20

This report shall not be reproduced, except in full, without the written approval of Timmons Group

44634

Arlington, Virginia Client Name:

Project Location:

Project Name:

Project #:

Technical Responsibility Signature Position Date

Matthew Thornton Laboratory Manager 2/7/20

Medium Sand

Coarse Sand

Gravel

< 2.00 mm and > 0.425 mm (#40)

< 4.75 mm and > 2.00 mm (#10)

< 75 mm and > 4.75 mm (#4)

1.8%Coarse Sand

Silt

Clay

Colloids Maximum Particle Size Gravel Liquid Limit Specific Gravity

Plastic Limit Medium Sand

3/8"

1.9% Fine Sand Silt & Clay Plastic Index Moisture Content* 25.3%

42.0% 35.7%

< 0.075 mm and > 0.005 mm

< 0.005 mm

< 0.001 mm

< 0.425 mm and > 0.075 mm (#200)

Light pinkish gray and brown, fine to coarse CLAYEY SAND, trace gravel (SC)

18.6%

0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

80.0

90.0

100.0

0.010.101.0010.00100.00

P er ce n t P as si n g

Millimeters

1" 3/4" 3/8" #4 #40 #200#100#102"3"

Timmons Group 430 Southlake Boulevard Suite B-15 Richmond, VA 23236

Form No. TR-Limits

Revision No. 2

Revision Date: 1/29/19

Report Date:

DMA TARC Visitor Center Test Date(s):

Tested By:

Location: Sample #: Sample Date:

Depth:

Liquid Limit Plastic Limit

Plastic Index Group Symbol

The specimen was air dried then prepared in general accordance with ASTM D4318 Section 11.2.

The Liquid Limit was determined using a Multi-Point Method with a Flat Grooving Tool.

References / Comments / Deviations:

*Moisture content of auger cuttings collected as bulk material is not representative of subgrade conditions at the time of drilling.

This report shall not be reproduced, except in full, without the written approval of Timmons Group

#100 47.6 #200 42.0

Matthew Thornton Laboratory Manager 2/7/20

Technical Responsibility Signature Position Date

Information included in this report relates only to material sampled at the time of testing.

#40 77.7

1" 3/4" 3/8" 100.0 #4 98.1 #10 96.3

2.5" 2"

1.5"

3"

Soil Properties

25.3% As-Received

Moisture Content*

Specific Gravity ---

ML

%Passing

Material Description: Light pinkish gray and brown, fine to coarse CLAYEY SAND, trace gravel (SC)

Client Name: Moseley Architects

SAMPLE INFORMATION

B-01 Bulk 1/13/2020

0.5 to 4 feet Offset: N/A Lab Control #: 2780

Project Name: 2/3/20 to 2/4/20

Project Location: Arlington, Virginia Ken Pruner

Liquid Limit, Plastic Limit and Plasticity Index

ASTM D4318

PROJECT INFORMATION

Project #: 44634 2/7/2020

15 20 25 30 35 35.0

36.0

37.0

38.0

39.0

40.0

41.0

42.0

43.0

44.0

45.0

46.0

47.0

48.0

49.0

50.0

51.0

52.0

53.0

54.0

55.0

M o is tu re

C o n te n t

# of Drops

Timmons Group 430 Southlake Boulevard Suite B-15 Richmond, VA 23236

Form No. TR-Compaction

Revision Date: 05/18/18

Report Date:

DMA TARC Visitor Center Test Date(s):

Tested By: Ken Pruner

Location: Sample #: Sample Date:

Depth:

References / Comments / Deviations:

*Moisture content of auger cuttings collected as bulk material is not representative of subgrade conditions at the time of drilling.

Content* Assumed Specific Gravity

Liquid Limit Plastic Limit Plastic Index

Laboratory Manager 2/7/20

100.0 No. 4 98.1

1.5" 3/4"

The Moisture-Density Curve Displayed relates only to material passing a No. 4 sieve.

Air-dried material passing a No. 4 sieve was prepared then compacted with a circular, manual rammer.

Sp.Gr.(OD) Absorption ---

MDD (pcf) ---

OMC (%) ---

Assumed Properties of Oversize Fraction

%Passing

3/8"

Information included in this report relates only to material sampled at the time of testing.

This report shall not be reproduced, except in full, without the written approval of Timmons Group

Corrected Moisture-Density

No. 10 96.3 No. 40 77.7 No. 200 42.0

Technical Responsibility Signature Position Date

Matthew Thornton

Material Description: Light pinkish gray and brown, fine to coarse CLAYEY SAND, trace gravel (SC)

ASTM D698 - Method A

Maximum Dry Density 113.0 PCF Optimum Moisture Content

As-Received 25.3%

2.65

Soil Properties

Moisture

MOISTURE-DENSITY RELATIONSHIP REPORT

Client Name: Moseley Architects

PROJECT INFORMATION

Project #: 44634 2/7/2020 Project Name: 1/30/20 to 1/31/20 Project Location: Arlington, Virginia

13.0 %

SAMPLE INFORMATION

B-01 Bulk 1/13/2020

0.5 to 4 feet Offset: N/A Lab Control #: 2780

4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

D R

Y D

E N

S

IT

Y

P C

F

MOISTURE CONTENT (%)

Uncorrected Proctor

ZAV Line @ 2.65 S.G.

Timmons Group 430 Southlake Boulevard Suite B-15 Richmond, VA 23236

Form No. TR-CBR

Revision No. 1

Revision Date: 05/18/18

Report Date:

Test Date(s):

Tested By:

Boring: Sample #: Sample Date:

Depth:

Soak Time (hours): 96 Surcharge Weight (lb): 20 Surcharge Stress (psf):

was performed on grading complying with CBR specification.

was performed on the entire gradation compacted in a 6" CBR mold.

References / Comments / Deviations:

*Moisture content of auger cuttings collected as bulk material is not representative of subgrade conditions at the time of drilling.

CBR (California Bearing Ratio) of Laboratory Compacted Soil

ASTM D1883

PROJECT INFORMATION

Project #: 44634 2/7/2020

N/A Lab Control #: 2780

Project Name: DMA TARC Visitor Center 2/1/20 to 2/5/20 Project Location: Arlington, Virginia Client Name: Moseley Architects

Soil Properties As-Received

25.3%Moisture

Material Description: Light pinkish gray and brown, fine to coarse CLAYEY SAND, trace gravel (SC) Uncorrected CBR Values Corrected CBR Values

CBR at 0.1 in. 5.6 CBR at 0.2 in. 6.1 CBR at 0.1 in 6.1

SAMPLE INFORMATION

B-01 Bulk 1/13/2020

0.5 to 4 feet Offset:

Content* Liquid Limit 45

CBR at 0.2 in 6.3

3/4" 3/8" 100.0

No. 4 98.1

Plastic Limit 19 Plastic Index 26

%Passing

1"

No. 200 42.0

ASTM D698 - Method A

MDD (pcf) 113.0

OMC (%) 13.0

No. 10 96.3 No. 40 77.7

No. 100 47.6

16.8% Moisture Content of Compacted Specimen 13.0% Moisture Content (top 1" after soaking) 19.0%

Before Soaking After Soaking Compactive Effort (Blows Per Layer) 56 Final Dry Density (pcf) 111.6

Information included in this report relates only to material sampled at the time of testing.

This report shall not be reproduced, except in full, without the written approval of Timmons Group

MLT and KP

Matthew Thornton Laboratory Manager 2/7/20 Technical Responsibility Signature Position Date

Percent Compaction 101.9% Percent Swell 1.8%

ASTM D698 - Method A % Retained on 3/4" sieve:ASTM D1883 0.0

Initial Dry Density (pcf) 115.1 Average Final Moisture Content

Corrected CBR Value at 0.1"

Corrected CBR Value at 0.2"

0.0 0.1 0.2 0.3 0.4 0.5

S tr es s

(p si

Strain (inches)

Timmons Group 430 Southlake Boulevard Suite B-15 Richmond, VA 23236

Form No. TR-pH of Soil

Revision No. 0

Revision Date: 02/28/19

References / Comments / Deviations:

The pH measurement was automatically corrected for temperature at the time of testing.

Test for Determining pH of Soil for Use in Corrosion Testing

AASHTO T289-19 (2013)

PROJECT INFORMATION

Project #: 44634 Report Date: 2/7/2020

Client Name: Moseley Architects

Project Name: DMA TARC Visitors center Test Date(s): 1/28/2020

Project Location: Arlingtion County, Virginia Tested By: Matthew Thornton

TEST INFORMATION

Lab Number: 2780

Sample Locaton: B-01

Sample Number: Bulk

Sample Depth (feet): 0.5 to 4

Test Temperature (°C): 24.9 pH (nearest 0.1): 6.3

Technical Responsibility Signature Position Date

Information included in this report relates only to material sampled at the time of testing.

This report shall not be reproduced, except in full, without the written approval of Timmons Group

Matthew Thornton Laboratory Manager 2/7/20

SCUSCS Classification:

Timmons Group 430 Southlake Boulevard Suite B-15 Richmond, VA 23236

44634 pH of Soil

Form No. TR-Electrical

Revision Date: 03/01/19

Report Date:

Test Date(s):

Tested By:

Boring: Sample #: Sample Date:

Depth:

References / Comments / Deviations:

The sample was tested in a 3.2 cm x 2.4 cm soil box with a pin spacing of 7.2 cm.

Moisture content of "As-Received" sample was reduced for testing purposes.

Testing performed on material passing a No. 4 sieve.

Additional test trials were performed after adding increasing amounts of distilled water.

Measured resistivity values were corrected for temperature per ASTM G57-06 (2012).

*Moisture content of auger cuttings collected as bulk material is not representative of subgrade conditions at the time of drilling.

Matthew Thornton Laboratory Manager 2/7/20

N/A Lab Control #: 2780 Light pinkish gray and brown, fine to coarse CLAYEY SAND, trace gravel (SC)

98.1

No. 100 No. 200

Content* Liquid Limit

Plastic Limit Plastic Index

Laboratory Measurement of Soil Electrical Resistivity Using a Four-Electrode Soil Box

Arlington County, Virginia Client Name:

Project Location:

Project Name:

Project #:

Moseley Architects

ASTM G57-06 (2012)

PROJECT INFORMATION

2/7/2020 1/28/20 to 1/29/20

44634 DMA TARC Visitors Center

Matthew Thornton

This report shall not be reproduced, except in full, without the written approval of Timmons Group

Technical Responsibility Signature Position Date

Information included in this report relates only to material sampled at the time of testing.

96.3

ASTM D698 Method A

Soil Properties

1" 3/4" 3/8"

No. 4 No. 10

Moisture

100.0

SAMPLE INFORMATION

B-01 Bulk

Material Description:

1/13/2020

0.5 to 4 feet Offset:

Approaching Minimum Resistivity (Ω-cm): 2,060

As-Received

%Passing

OMC (%) 13.0

77.7 47.6 42.0

No. 40

MDD (pcf) 113.0

25.3%

1,500

2,000

2,500

3,000

3,500

4,000

4,500

5,000

5,500

6,000

0 5 10 15 20 25 30 35 40 45 50 55 60

E le ct ri ca l R es is ti v it y

(Ω -c m

Moisture Content (%)

Timmons Group 430 Southlake Boulevard Suite B-15

Richmond, VA 23236

44634 B-01 0.5-4 ft ER

Form No. TR-ORP of Soil

Revision Date: 02/28/19

Location: Sample #: Sample Date:

Depth:

References / Comments / Deviations:

*Moisture content of auger cuttings collected as bulk material is not representative of subgrade conditions at the time of drilling.

Testing performed on material in the "As-Received" condition.

This report shall not be reproduced, except in full, without the written approval of Timmons Group

Matthew Thornton Laboratory Manager 2/7/20 Technical Responsibility Signature Position Date

Information included in this report relates only to material sampled at the time of testing.

Test Date(s): 1/28/2020

Project Location: Arlington County, Virginia Tested By: Matthew Thornton

Measurement of Oxidation-Reduction Potential of Soil

PROJECT INFORMATION

Project #: 44634 Report Date: 2/7/2020

Material Description: Light pinkish gray and brown, fine to coarse CLAYEY SAND, trace gravel (SC)

ASTM G200-09 (2014)

SAMPLE INFORMATION

B-01 Bulk 1/13/2020

Client Name: Moseley Architects

Project Name: DMA TARC Visitors Center

0.5 to 4 feet Offset: N/A Lab Control #: 2780

Soil Properties

Moisture

25.3%Content

During Test*

Liquid Limit 45

Plastic Limit 19

Plastic Index 26

%Passing

1"

3/4"

3/8" 100.0

No. 4 98.1

No. 10 96.3

No. 40 77.7

No. 100 47.6

No. 200 42.0

Reading at End of Test (mV) 280.3

ASTM D698 Method A

MDD (pcf) 113.0

OMC (%) 13.0

0 5 10 15 20 25 30

R ea d in g s

(m V

Time (minutes)

Timmons Group 430 Southlake Boulevard Suite B-15

Richmond, VA 23236

44634 B-01 0.5-4 ft ORP

Form No. TR-ORP of Soil

Revision Date: 02/28/19

References / Comments / Deviations:

*Moisture content of auger cuttings collected as bulk material is not representative of subgrade conditions at the time of drilling.

Testing performed on material in the "As-Received" condition.

Technical Responsibility Signature Position Date

TEST INFORMATION

ANSI/AWWA C105/A21.5-18 Appendix A.1.4 : A positive sulfide reaction reveals a potential problem caused by sulfate-reducing bacteria. The sodium azide-iodine qualitative test is used to identify sulfides. In this determination, a solution of 3 percent sodium azide in a 0.1N iodine solution is introduced into a test tube containing a sample of the soil. Sulfides catalyze the reaction between sodium azide and iodine, resulting in nitrogen. If strong bubbling or foaming results, sulfides are present, as are sulfate-reducing bacteria. If very slight bubbling is noted, sulfides are probably present in small concentration, and the result is noted as a trace.

Information included in this report relates only to material sampled at the time of testing.

This report shall not be reproduced, except in full, without the written approval of Timmons Group

Matthew Thornton Laboratory Manager 2/7/20

Qualitative Test to Identify Sulfides in Soil

PROJECT INFORMATION

Project #: 44634 Report Date: 2/7/2020

Client Name: Moseley Architects

Project Name: DMA TARC Visitors Center Test Date(s): 1/28/2020

Project Location: Arlington County, Virginia Tested By: Matthew Thornton

ANSI/AWWA C105/A21.5-18 Appendix A.1.4

Sample Locaton: B-01

Sample Number: Bulk

Lab Number: 2780

Sample Depth (feet): 0.5 to 4

USCS Classification: SC

Observation: Trace

Timmons Group 430 Southlake Boulevard Suite B-15

Richmond, VA 23236

44634 B-01 0.5-4 ft Sulfides

Form No. TR-GSA

Revision Date:…