Mr. Timmy Baynes

June5, 2012Mr. Timmy BaynesKerr-Tar Regional Council of GovernmentsPO Box 7091724 Graham AvenueHenderson, North Carolina 27536

RE: Addendum No. 1 - Additional Geotechnical ExplorationTriangle North Warren Site VerificationWarren County, NCECS Project Number 06:18961-A

Dear Mr. Baynes:

As authorized, ECS Carolinas, LLP has completed the additional geotechnical services for the above referenced project. ECS previously performed a subsurface exploration and geotechnical report (#06:12499-B) dated November 22, 2004 and our conclusions and recommendations are supplemented by this Addendum No. 1.

PROJECT UNDERSTANDING

Based on the information provided to us, we understand it is being proposed to certify this siteunder the current NC DOC’s Certified Site Program. It is our understanding that the original site consists of 3 parcels totaling approximately 870 acres, including Parcel ID Numbers (PIN) B6 37A, B6 36B, and B6 37B1. It is proposed to expand the site to include parcel A6 29 which adds approximately 168 acres to the existing site, totaling approximately 1038 acres. The site consists primarily of agricultural fields and undeveloped woodlands.

EXPLORATION PROCEDURES

The soil borings were performed with CME 450 auger drilling rig, which utilized hollow-stemaugers to advance the boreholes. Drilling fluid was not used to advance the borings.

Representative soil samples were obtained by means of the split-barrel sampling procedure in general accordance with ASTM Specification D-1586. In this procedure, a 2-inch O. D. split-barrel sampler is driven into the soil a distance of 18 inches by a 140 pound hammer with a free fall of 30 inches. The number of blows required to drive the sampler through the final 12 inch interval is termed the Standard Penetration Test (SPT) N-value and is indicated for each sample on the boring logs.

The SPT N-value can be used to provide a qualitative indication of the in-place relative density of cohesionless soils. In a less reliable way, SPT N-values provide an indication of consistency for cohesive soils. These indications of relative density and consistency are qualitative, since many factors can significantly affect the SPT N-value and prevent a direct correlation between drill crews, drill rigs, drilling procedures, and hammer-rod-samplerassemblies.

SITE

REVISIONS

DRAFTSMAN

ENGINEER

DATE

SHEET

PROJECT NO.

SCALEAVG

CNW

1" = 3000'

18961-A

Figure 1

5-05-12

0

5

10

15

20

25

30

S-1

S-2

S-3

S-4

S-5

S-6

SS

SS

SS

SS

SS

SS

18

18

18

18

18

18

18

18

18

18

18

18

Topsoil Depth [2"]Moist, Stiff, Reddish Brown, Fine Sandy ClayeySILT, (ML)

Moist, Very Stiff, Reddish Brown, Tan, FineSandy SILT, With Mica, (ML)

Moist, Very Stiff, Gray, Brown, Fine SandySILT, With Mica, Rock Fragments, (ML)

Moist, Very Stiff, Brown, Fine Sandy SILT, WithMica, (ML)

END OF BORING @ 20.00'

346

141522

121416

111214

111210

11912

10

37

30

26

22

21

CLIENT

Kerr-Tar Regional Council of Governments

JOB #

18961-A

BORING #

B-101

SHEET

PROJECT NAMESite Certification- Triangle North WarrenExpansion

ARCHITECT-ENGINEER

SITE LOCATION

, , Warren County

THE STRATIFICATION LINES REPRESENT THE APPROXIMATE BOUNDARY LINES BETWEEN SOIL TYPES. IN-SITU THE TRANSITION MAY BE GRADUAL.

WL DRY WS WD BORING STARTED 05/09/12

WL(BCR) WL(ACR) BORING COMPLETED 05/09/12 CAVE IN DEPTH @ 13.50'

WL RIG CME 450 FOREMAN S. Bowman DRILLING METHOD 2.25" I.D. HSA

SURFACE ELEVATION

DESCRIPTION OF MATERIAL

10 20 30 40 50+

20% 40% 60% 80% 100%

1 2 3 4 5+

ENGLISH UNITS

BOTTOM OF CASING LOSS OF CIRCULATION

CALIBRATED PENETROMETERTONS/FT2

PLASTICLIMIT

WATERCONTENT %

LIQUIDLIMIT %

ROCK QUALITY DESIGNATION & RECOVERYRQD% REC.%

STANDARD PENETRATIONBLOWS/FT

1 OF 1

0

5

10

15

20

25

30

S-1

S-2

S-3

S-4

S-5

S-6

SS

SS

SS

SS

SS

SS

18

18

18

18

18

18

18

18

18

18

18

18

Moist, Very Stiff, Reddish Brown, Fine SandySILT, With Mica, (ML)

Moist, Very Stiff, Brown, Tan, Fine SandyMicaceous SILT, (ML)

Moist, Very Stiff, Tan, Gray, Fine SandySILT, (ML)


61113

131416

6710

8109

579

5910

24

30

17

19

16

19

CLIENT


JOB #

18961-A

BORING #

B-102

SHEET


ARCHITECT-ENGINEER

SITE LOCATION

, , Warren County





SURFACE ELEVATION


10 20 30 40 50+

20% 40% 60% 80% 100%

1 2 3 4 5+

ENGLISH UNITS



PLASTICLIMIT

WATERCONTENT %

LIQUIDLIMIT %



1 OF 1

0

5

10

15

20

25

30

S-1

S-2

S-3

S-4

S-5

S-6

SS

SS

SS

SS

SS

SS

18

18

18

18

18

18

18

18

18

18

18

18

Topsoil Depth [2"]Moist, Stiff, Greenish Gray, Brown, Fine SandySILT, With Mica, Trace Clay, (ML)

Moist, Hard, Brown, Fine Sandy SILT, WithMica, (ML)

Moist, Very Hard to Very Stiff, Brown, Black,Fine Sandy Micaceous SILT, (ML)


468

162425

132228

192727

92030

111316

14

49

50

54

50

29

CLIENT


JOB #

18961-A

BORING #

B-103

SHEET


ARCHITECT-ENGINEER

SITE LOCATION

, , Warren County





SURFACE ELEVATION


10 20 30 40 50+

20% 40% 60% 80% 100%

1 2 3 4 5+

ENGLISH UNITS



PLASTICLIMIT

WATERCONTENT %

LIQUIDLIMIT %



1 OF 1

UNIFIED SOIL CLASSIFICATION SYSTEM (ASTM D2487)

Major Divisions GroupSymbols Typical Names Laboratory Classification Criteria

GWWell-graded gravels, gravel-sand mixtures, little or no fines Cu = D60/D10 greater than 4

Cc = (D30)2/(D10xD60) between 1 and 3

GPPoorly graded gravels, gravel-sand mixtures, little or no fines Not meeting all gradation requirements for GW

d

GMa

u

Silty gravels, gravel-sandmixtures

Atterberg limits below “A” line or P.I. less than 4

GC Clayey gravels, gravel-sand-clay mixtures

Atterberg limits below “A” line or P.I. less than 7

Above “A” line with P.I. between 4 and 7 are borderline cases requiring use of dual symbols

SW Well-graded sands, gravelly sands, little or no fines

Cu = D60/D10 greater than 6Cc = (D30)2/(D10xD60) between 1 and 3

SP Poorly graded sands, gravelly sands, little or no fines

Not meeting all gradation requirements for SW

d

SMa

u

Silty sands, sand-silt mixtures Atterberg limits above “A” line or P.I. less than 4

SC Clayey sands, sand-claymixtures

Atterberg limits above “A” line with P.I. greater than 7

Limits plotting in CL-MLzone with P.I. between 4 and 7 are borderline cases requiring use of dual symbols

ML

Inorganic silts and very fine sands, rock flour, silty or clayey fine sands, or clayey silts with slight plasticity

CL

Inorganic clays of low to medium plasticity, gravelly clays, sandy clays, silty clays, lean clays

OLOrganic silts and organic silty clays of low plasticity

MHInorganic silts, micaceous or diatomaceous fine sandy or silty soils, elastic silts

CH Inorganic clays of high plasticity, fat clays

OH Organic clays of medium to high plasticity, organic silts

Pt Peat and other highly organic soils

Plasticity Chart

0

10

20

30

40

50

60

0 10 20 30 40 50 60 70 80 90 100

Liquid Limit

"A" line

CH

MH andOH

CL

ML and OLCL-ML

a Division of GM and SM groups into subdivisions of d and u are for roads and airfields only. Subdivision is based on Atterberg limits; suffix d used when L.L. is 28 or less and the P.I. is 6 or less; the suffix u used when L.L. is greater than 28.b Borderline classifications, used for soils possessing characteristics of two groups, are designated by combinations of group symbols. For example: GW-GC,well-graded gravel-sand mixture with clay binder. (FromTable 2.16 - Winterkorn and Fang, 1975)

REFERENCE NOTES FOR BORING LOGS

I. Drilling Sampling Symbols

SS Split Spoon Sampler ST Shelby Tube SamplerRC Rock Core, NX, BX, AX PM PressuremeterDC Dutch Cone Penetrometer RD Rock Bit DrillingBS Bulk Sample of Cuttings PA Power Auger (no sample)HSA Hollow Stem Auger WS Wash sampleREC Rock Sample Recovery % RQD Rock Quality Designation %

II. Correlation of Penetration Resistances to Soil PropertiesStandard Penetration (blows/ft) refers to the blows per foot of a 140 lb. hammer falling 30 inches on a 2-inch OD split-spoon sampler, as specified in ASTM D 1586. The blow count is commonly referred to as the N-value.

A. Non-Cohesive Soils (Silt, Sand, Gravel and Combinations)

Density Relative PropertiesUnder 4 blows/ft Very Loose Adjective Form 12% to 49%5 to 10 blows/ft Loose With 5% to 12%11 to 30 blows/ft Medium Dense31 to 50 blows/ft DenseOver 51 blows/ft Very Dense

Particle Size IdentificationBoulders 8 inches or largerCobbles 3 to 8 inchesGravel Coarse 1 to 3 inches

Medium ½ to 1 inchFine ¼ to ½ inch

Sand Coarse 2.00 mm to ¼ inch (dia. of lead pencil)Medium 0.42 to 2.00 mm (dia. of broom straw)Fine 0.074 to 0.42 mm (dia. of human hair)

Silt and Clay 0.0 to 0.074 mm (particles cannot be seen)

B. Cohesive Soils (Clay, Silt, and Combinations)

Blows/ft ConsistencyUnconfined

Comp. Strength Qp (tsf)

Degree of Plasticity

PlasticityIndex

Under 2 Very Soft Under 0.25 None to slight 0–43 to 4 Soft 0.25-0.49 Slight 5–75 to 8 Medium Stiff 0.50-0.99 Medium 8–229 to 15 Stiff 1.00-1.99 High to Very High Over 2216 to 30 Very Stiff 2.00-3.0031 to 50 Hard 4.00–8.00Over 51 Very Hard Over 8.00

III. Water Level Measurement Symbols

WL Water Level BCR Before Casing Removal DCI Dry Cave-InWS While Sampling ACR After Casing Removal WCI Wet Cave-InWD While Drilling Est. Groundwater Level Est. Seasonal High GWT

The water levels are those levels actually measured in the borehole at the times indicated by the symbol. The measurements are relatively reliable when augering, without adding fluids, in a granular soil. In clay and plastic silts, the accurate determination of water levels may require several days for the water level to stabilize. In such cases, additional methods of measurement are generally applied.

PRELIMINARY SUBSURFACE EXPLORATION AND GEOTECHNICAL ENGINEERING ANALYSIS

PROPOSED WARREN COUNTY HUB SITE WARREN COUNTY, NORTH CAROLINA

PREPARED FOR:

Ms. Crystal Morphis The Sanford Holshouser Business Development Group

219 Fayetteville Street, Suite 1000 Raleigh, North Carolina 27601

ECS, LTD. PROJECT NUMBER 12499-B

November 22, 2004

Preliminary Subsurface Exploration and Geotechnical Engineering Proposed Warren County HUB Site, Warren County, North Carolina ECS Project #12499-B

4

17.5 feet below existing grades, respectively. Detailed descriptions of the soils encountered at each boring are presented on the boring logs in Appendix B. Conditions should be expected to vary between borings. Laboratory test results are presented in Appendix C. Groundwater was encountered in boring B-8, B-13, B-17, B-34, and B-39 at depths of 24.8, 16.8, 14.8, 23.4, and 16.8 feet below existing grades, respectively. In general, groundwater should be anticipated to be at or near the ground surface in drainage features and near streams. Perched water will likely be encountered at the surface of the bedrock and at soil strata with lower permeability. Groundwater levels are anticipated to vary seasonally.

Seismic Conditions Based on Section 1615 of the 2002 North Carolina Building Code (2000 International Building Code with North Carolina Amendments), the site has the following characteristics: Maximum Considered Earthquake Ground Motion 0.2 sec. Spectral Response – 0.19g Maximum Considered Earthquake Ground Motion 1.0 sec. Spectral Response – 0.09 g Site Classification – D (for majority of the site) Site Coefficient Fa - 1.6 Site Coefficient Fv – 2.4 Spectral Response Acceleration SDS – 0.203 g Spectral Response Acceleration SDI – 0.144 g Site Classification – C (portions of the site with shallow partially weathered rock) Site Coefficient Fa - 1.2 Site Coefficient Fv – 1.7 Spectral Response Acceleration SDS – 0.152 g Spectral Response Acceleration SDI – 0.102 g Please note that depending on the finished grade elevations, the site classification may change. Therefore, we recommend verifying the site classification once the final site grades have been established. The site classification will likely vary between structures and areas of the site. Development of the general design response spectrum curve in accordance with Section 1615.1.4 requires the fundamental period for the structure; and therefore, is left to the Structural Engineer. The soils at this site upon which a structure would be supported on, firm native soil or compacted structural fill overlying firm native soil, are not anticipated to experience a significant loss of strength from a seismic event per Chapter 18 of the 2002 North Carolina


5

Building Code (2000 International Building Code with North Carolina Amendments).

Site Development Average topsoil and root mass stripping depths are anticipated to be on the order of 6 to 10 inches, with greater depths in wet or heavily vegetated areas. We anticipate that some undercutting will be required, particularly in low lying areas and drainage features. More extensive undercutting would be required during the winter and spring, than during the relatively drier summer and fall. Leaving rough graded areas 6 inches higher to protect the underlying soil in cut areas is recommended. Some of the near-surface soils at the site are expansive, expansion index greater than 20, as defined by the 2002 North Carolina Building Code. Expansive soils are soils that swell as their moisture content increases and shrink as their moisture content decreases. Standard techniques used to address potentially expansive soils in this area include: undercutting and replacing with less expansive materials, lime or cement stabilization, careful moisture control to maintain the soil near the optimum moisture content, placing footings at a greater depth, maintaining a separation of at least 2 feet between pavement/floor slab and expansive soils, and post-tensioned floor slabs.

Foundations The subsurface conditions encountered at the site are suitable to support shallow foundations, provided potentially expansive soils and any isolated soft/wet soils are appropriately addressed. For planning purposes, we recommend a net allowable soil bearing pressure of 3,000 pounds per square foot for footings bearing on firm native soils or engineered structural fill over firm natural soils. Highly plastic soils may be placed as controlled fill provided they are used 10 feet or more below finished grades and can be adequately moisture conditioned and compacted. The frost depth specified for this site is 12 inches. In order to provide adequate frost cover protection and embedment for bearing capacity, we recommend that footings be located at minimum depths of 18 inches below finished exterior grades. In order to prevent disproportionately small footing sizes, we recommend that strip footings have a minimum width of 18 inches and that isolated column footings have a minimum lateral dimension of 24 inches. The minimum dimension sizes, as recommended above, are utilized to reduce foundation difficulties as a result of local shear or "punching" action. An experienced materials testing firm should observe the foundation subgrade to verify that conditions exposed at the subgrade would be suitable for the design bearing pressures. If unsuitable materials are encountered at the base of a foundation excavation, it will be


6

necessary to lower the base of the footing through the unsuitable materials or to undercut the unsuitable soils and to restore original bearing levels by placing engineered fill materials, or “lean” concrete. Exposure to the environment may weaken the soils at the footing bearing levels if the foundation excavations remain open for too long a time. Therefore, foundation concrete should be placed during the same day that excavations are made. If the bearing soils are softened by surface water intrusion or exposure, the softened soils must be removed from the foundation excavations prior to placement of concrete.

Subgrade Walls Subgrade walls, such as basement walls or retaining walls, are frequently used for grade transitions. We recommend that all walls either be provided with a gravity drainage system, or that they are designed for hydrostatic pressures. Potentially expansive soils should not be used as backfill against walls, as over time they will tend to act as a “jack” against the wall. If modular block retaining walls are used at the site, the strength parameters of the soil to be used in the reinforced zone should be evaluated with either triaxial or direct shear testing. Similarly, specific testing should be conducted to determine “active”, “passive”, and “at-rest” earth pressures.

General This preliminary report has been prepared in order to aid in the evaluation of this property and to assist in preliminary planning. Before any specific project is undertaken, a detailed subsurface exploration program tailored to that project should be undertaken. Subsurface conditions can be expected to vary between the widely-spaced (one boring per every approximately 20 acres) borings performed as part of this project. It is recommended that all construction operations dealing with earthwork and foundations be reviewed by an experienced soils engineer to provide information on which to base a decision as to whether the design requirements are fulfilled in the actual construction. We strongly recommend the owner directly retain an independent testing firm, such as ECS, Ltd, to observe all fill placements, proofrolling, and footing subgrade preparation. If you wish, we would welcome the opportunity to provide construction material testing services for you during construction.

APPENDICES

APPENDIX A

FIGURES

APPENDIX B

FIELD EXPLORATION, BORING LOGS,

SOIL CLASSIFICATION SYSTEM, DESCRIPTION, AND TERMINOLOGY

Mr. Timmy Baynes

Documents

Transcript of Mr. Timmy Baynes