Geotechnical Engineering Report Hefner VAMC Expansion...

Geotechnical Engineering Report Hefner VAMC Expansion Salisbury, North Carolina

S&ME Project No. 1351-10-004

Prepared For:

HDR Architecture, Inc. 440 South Church Street, Suite 1000

Charlotte, North Carolina 28202

Prepared By:

S&ME, Inc. 9751 Southern Pine Boulevard Charlotte, North Carolina 28273

February 15, 2010

TABLE OF CONTENTS

1.0 INTRODUCTION...........................................................................................................................1 1.1 PROJECT AND SITE DESCRIPTIONS .............................................................................................1 1.2 PURPOSE AND SCOPE .................................................................................................................2

2.0 EXPLORATION PROCEDURES ................................................................................................2 2.1 FIELD TESTING .............................................................................................................................2 2.2 LABORATORY TESTING ................................................................................................................2

3.0 AREA GEOLOGY AND SUBSURFACE CONDITIONS ..........................................................3 3.1 PHYSIOGRAPHY AND AREA GEOLOGY.........................................................................................3 3.2 SUBSURFACE CONDITIONS ............................................................................................................4

4.0 SITE CONSTRUCTION RECOMMENDATIONS ....................................................................5 4.1 GENERAL ......................................................................................................................................5

4.1.1 Site Preparation-General ........................................................................................................5 4.1.2 Existing Fill Soils and Plastic Soils.........................................................................................6 4.1.3 Proofrolling .............................................................................................................................6 4.1.4 Subgrade Repair after Exposure .............................................................................................7 4.1.5 Cut and Fill Slopes ..................................................................................................................7 4.1.6 Excavations .............................................................................................................................7 4.1.7 Temporary Excavation Stability ..............................................................................................7 4.1.8 Temporary Dewatering ...........................................................................................................8 4.1.9 Effects of Construction ............................................................................................................8 4.1.10 Fill Material and Placement...............................................................................................9

5.0 DESIGN RECOMMENDATIONS................................................................................................9 5.1 SEISMIC DESIGN PARAMETERS ...................................................................................................9 5.2 FOUNDATION SUPPORT – BASEMENT/TUNNEL FOUNDATIONS...................................................9 5.3 FOUNDATION SUPPORT – AT-GRADE FOUNDATIONS ...............................................................10

5.3.1 Shallow Foundations with Geopiers......................................................................................11 5.3.2 Auger-Cast Piles....................................................................................................................12

5.4 SETTLEMENT ..............................................................................................................................13 5.5 FLOOR SLABS.............................................................................................................................13 5.6 BASEMENT WALLS .....................................................................................................................14 5.7 CORROSION POTENTIAL OF UNDERGROUND FACILITIES ..........................................................15 SOIL CORROSIVITY VERSUS RESISTIVITY ..................................................................................................15 5.8 PAVEMENTS ...............................................................................................................................16

6.0 LIMITATIONS OF REPORT.....................................................................................................17 APPENDIX Site Vicinity Map, Figure 1 Boring Location Plan Plan, Figure 2 Generalized Subsurface Profile, Fig. 3 Legend to Soil Classification and Symbols Boring Logs, B-1 through B-12 Summary of Laboratory Test Data

Hefner VAMC Expansion S&ME Project No. 1351-10-004 Salisbury, North Carolina February 15, 2010

1.0 INTRODUCTION

1.1 Project and Site Descriptions Project information is based on an RFP e-mailed to Marc Cerino of S&ME on January 5, 2010 from Mr. Charles Reed of HDR Architecture, Inc. It’s also based on a subsequent e-mail to Brian McKean of S&ME that included the location of soil borings requested by the site civil engineer. The e-mail also included the anticipated location of a below grade basement area that will connect to the existing below-grade tunnel. Phone conversations and email correspondence during the course of the project provided additional information. We understand plans are to construct a new 25,000 s.f. mental health building on the Hefner VAMC campus located in Salisbury, North Carolina.

Proposed Site

The new building will be located between existing Buildings 11 and 4 and will be a one-story structure that will be capable of an expansion to a 3-story structure. A future expansion to the west is also planned for a later date. A portion of the building will have a full basement level with elevators that will connect to the below-grade tunnel that currently connects Buildings 11 and 4. The new building will be a steel structure with a brick façade with maximum column loads on the order of 225 to 400 kips. A preliminary load diagram was provided by HDR’s structural engineer outlining anticipated loads at column locations. New parking and driveways will also be constructed. Site conditions consist of a generally open area between Buildings 4 and 11 consisting of grassed areas with parking and driveway areas. Several large trees are present around the site. Site topography ranges from 719 feet (MSL) near Building 4 down to 715 feet (MSL) near Building 11. Underground utilities are present throughout the planned project area.

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1.2 Purpose and Scope The purpose of this geotechnical study was to explore the subsurface conditions at the site and develop geotechnical recommendations for the design and construction of the project. S&ME has completed the following scope of geotechnical services for this project:

• Visited the site to observe site surface conditions and mark proposed boring locations, and coordinate activities with on-site personnel.

• Contacted North Carolina One Call to mark the locations of existing underground utilities in the proposed exploration areas.

• Mobilized a power drilling rig mounted on an all-terrain vehicle and crew to the site.

• Drilled a total of twelve soil test borings at the site. • Backfilled the boreholes with soil cuttings and installed a hole closure device near

the ground surface in each borehole. • Performed laboratory testing consisting of Atterberg Limits, moisture content

tests, pH, resistivity and sulfates content. • Prepared this geotechnical engineering report.

2.0 EXPLORATION PROCEDURES

2.1 Field Testing S&ME crews and equipment drilled a total of 12 soil test borings (B-1 through B-12) to depths ranging from approximately 7.5 to 40 feet below existing grades. The borings were advanced at the approximate locations shown on the Boring Location Plan (Figure No. 2) in the Appendix. Boring locations were located in the field by S&ME personnel by measuring distances and estimating right angles from existing site features. Boring locations should be considered approximate. A Diedrich D-50 drill rig was used to advance hollow-stem, continuous flight augers. Standard Penetration Test (SPT) split-spoon sampling was performed at designated intervals in general accordance with ASTM D 1586 to provide an index for estimating soil strength and relative density or consistency and to retrieve samples for soil classification purposes. The drill rig used utilized an Automatic hammer to perform SPT testing. Representative portions of each split-spoon sample were placed in glass jars and taken to our laboratory. Water level measurements were attempted at the termination of drilling activities. All boreholes were backfilled with soil cuttings prior to leaving the site.

2.2 Laboratory Testing A geotechnical staff professional visually examined each sample in general accordance with the Unified Soil Classification System (USCS) to estimate the distribution of grain sizes, plasticity, organic content, moisture condition, color, presence of lenses and seams and apparent geological origin. The results of the classifications, as well as the field test

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results, are presented on the individual boring logs included in the Appendix. Similar materials were grouped into strata on the logs. The strata contact lines represent approximate boundaries between the soil and rock types; the actual transition between the soil and rock types in the field may be gradual in both the horizontal and vertical directions. Supplemental laboratory testing was performed in S&ME’s laboratory on selected soil samples obtained during the field exploration. Laboratory testing included Atterberg Limits Natural Soil Moisture Content, Grain Size Distribution, pH and resistivity. Results of the laboratory testing are attached at the end of this report.

3.0 AREA GEOLOGY AND SUBSURFACE CONDITIONS

3.1 Physiography and Area Geology The site is located in the Charlotte Belt section of the Piedmont Physiographic Province of North Carolina as shown in the following figure. The Piedmont Province generally consists of well-rounded hills and ridges, which are dissected by a well-developed system of draws and streams. The Piedmont Province is predominantly underlain by metamorphic rock (formed by heat, pressure and/or chemical action) and igneous rock (formed directly from molten material), which were initially formed during the Precambrian and Paleozoic eras. The volcanic and sedimentary rocks deposited in the Piedmont Province during the Precambrian eras were the host for the metamorphism and were changed to gneiss and schist. The more recent Paleozoic era had periods of igneous emplacement, with at least several episodes of regional metamorphism resulting in the majority of the rock types seen today.

General Geologic Provinces and Belts of North Carolina

APPROXIMATE SITE

The topography and relief of the Piedmont Province have developed from differential weathering of the igneous and metamorphic rock. Because of the continued chemical and physical weathering, the rocks in the Piedmont Province are now generally covered with a mantle of soil that has weathered in place from the parent bedrock. These soils have variable thicknesses and are referred to as residuum or residual soils. The residuum is typically finer grained and has higher clay content near the surface because of the advanced weathering. Similarly, the soils typically become coarser grained with

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increasing depth because of decreased weathering. As the degree of weathering decreases, the residual soils generally retain the overall appearance, texture, gradation and foliations of the parent rock. The boundary between soil and rock in the Piedmont is not sharply defined. A transitional zone termed “partially weathered rock” is normally found overlying the parent bedrock. Partially weathered rock (PWR) is defined for engineering purposes as residual material with Standard Penetration Resistances (N-values) exceeding 100 blows per foot. The transition between hard/dense residual soils and partially weathered rock occurs at irregular depths due to variations in degree of weathering. A depiction of typical weathering profiles in the Piedmont Province is presented in the following figure:

Typical Piedmont Weathering Profiles (After Sowers/Richardson, 1983)

Groundwater is typically present in the residual soils and within fractures in the partially weathered rock or underlying bedrock in the Piedmont. On upland ridges in the Piedmont, groundwater may or may not be present in the residual soils above the partially weathered rock and bedrock. Alluvial soils, which have been transported and deposited by water, are typically found in floodplains and are generally saturated to within a few feet of the ground surface. Fluctuations in groundwater levels are typical in residual soils and partially weathered rock in the Piedmont, depending on variations in precipitation, evaporation, and surface water runoff. Seasonal high groundwater levels are expected to occur during or just after the typically wetter months of the year (November through April).

3.2 Subsurface Conditions The soil test borings initially encountered a thin layer of topsoil and grass or pavement section (asphalt and ABC Stone) underlain by fill soils, residual soils and partially weathered rock. The generalized subsurface conditions at the site are further described below. For more detailed soil descriptions and stratifications at a particular boring location, the respective boring log should be reviewed. Fill Soils: Beneath the grass/rootmat or pavement section, fill soils were encountered in each of the borings to depths ranging from 3 to 10 feet below the ground surface. The fill soils generally consist of sandy silts, clayey silt (ML), silty sand (SM) and silty clay (CH,

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CL). N-values obtained in the borings ranged from 3 to 18 blows per foot (bpf). Boring B-12 was terminated in the fill at a depth of 10 feet. Residual Soils: Beneath the fill materials, residual soils were encountered. The residual soils generally consisted of sandy silts (ML) and silty sand (SM). N-values ranged from 4 to 82 bpf in the residual soils. Partially Weathered Rock (PWR): Partially weathered rock materials were encountered at depths ranging from 23 to 39 feet below the existing ground surface in Borings B-3, B-6A, B-8 and B-10. When sampled the partially weathered rock typically broke down to silty fine sands. Water Levels: Groundwater level measurements were attempted in the borings at the completion of drilling operations. Due to public safety concerns, holes were backfilled at the end of each day. All of the borings were dry when water measurements were taken. The borehole cave-in depths for the soil test borings may be an indication of groundwater at or near the cave-in depth when the borings are extended below the groundwater level and are also included on the individual logs. Water levels tend to fluctuate with seasonal and climatic variations, as well as with some types of construction operations. Therefore, groundwater may be encountered during construction at depths not indicated by the borings.

4.0 SITE CONSTRUCTION RECOMMENDATIONS

4.1 General Our conclusions and recommendations are based on the project information outlined previously and on the data obtained from the field-testing program. If the structural loading, geometry or proposed building locations are changed or significantly differ from those outlined, or if conditions are encountered during construction that differ from those encountered by the soil test borings, S&ME, Inc. requests the opportunity to review our recommendations based on the new information and make any necessary changes.

4.1.1 Site Preparation-General Prior to construction, the entire building and pavement areas should be stripped of any topsoil, rootmat, trash, debris, and organic materials to a minimum of 10 feet outside the structural and pavement limits. The resulting excavations should be backfilled with properly compacted structural fill. Any existing underground utilities or other obstructions in the proposed construction areas should also be properly excavated, removed, abandoned, or re-routed to facilitate the proposed grading and foundation installation. The resulting excavations should be properly backfilled as described later in this report. For existing utilities that are to remain in place, the suitability of existing backfill soils should be evaluated in the field at time of construction.

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4.1.2 Existing Fill Soils and Plastic Soils As indicated, existing fill soils were encountered in the borings across the site. Based on our observations, the existing fill soils are marginally to well compacted, contain isolated organics, and consist of varying amounts of highly plastic soils. We generally anticipate that a majority of these materials may remain in-place provided they are stable upon proofrolling observations. If existing fill materials in an area to directly support pavements, new structural fill or building slabs are unstable, they should be undercut and replaced with properly compacted structural fill. The depth of undercut should be determined in the filed by the on-site geotechnical engineer. Existing fill materials excavated during construction of the basement area of the new building are not suitable for re-use as backfill against the new basement walls. Excavated existing fill materials should be placed in non-structural areas of the project or hauled off-site. It should be noted that these soils are fairly low-strength, sensitive to moisture, and can degrade quickly when subjected to changes in moisture. Additional preparation of these materials (undercutting, moisture-conditioning, etc.) should be anticipated particularly if construction occurs during the wetter, cooler months of the year (November through March).

4.1.3 Proofrolling Upon completion of required stripping operations, we recommend that areas to provide support for the foundations, floor slab, structural fill and any pavement areas be proofrolled with a loaded dump truck or similar pneumatic tired vehicle (minimum loaded weight of 20 tons) under the observation of a staff professional or a senior soil technician. After excavation of the site has been completed, the exposed subgrade in cut areas should also be proofrolled. The proofrolling procedures should consist of four complete passes of the exposed areas, with two of the passes being in a direction perpendicular to the preceding ones. Any areas which deflect, rut or pump excessively during proofrolling or fail to improve after successive passes should be undercut to suitable soils and replaced with compacted structural fill. Based on the borings, undercutting of unstable fill soils should be anticipated in isolated areas within the building and in proposed roadway areas where existing fill materials are present at subgrade elevations. Based on the borings, we anticipate that these materials may not be suitable for pavement support in their current condition and will require remediation (undercut and replace) prior to placement of the new pavement section. Additional repair methods may also include the use of geotextile fabrics or geogrids. After the proofrolling operation has been completed and the subgrade determined to be stable, site grading should proceed immediately. If construction progresses during wet weather, the proofrolling operation should be repeated with at least one pass in each direction immediately prior to placing aggregate base course in the parking areas. If unstable conditions are exposed during this operation, then undercutting or scarifying may be required.

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4.1.4 Subgrade Repair after Exposure The on-site silty and clayey soils are fairly low-strength, sensitive to moisture, and can degrade quickly if exposed to water. Because of this, the exposed subgrade soils may deteriorate when exposed to construction activity and environmental changes such as freezing, erosion, softening from ponded rainwater, and rutting from construction traffic. We recommend that exposed subgrade surfaces in the pavement and slab-on-grade areas that have deteriorated be properly repaired by scarifying and re-compacting immediately prior to additional construction. It should be noted that the level of difficulty and cost of developing a stable subgrade will depend upon the weather conditions before and during construction as well as the time available to stabilize the subgrade. If earthwork must be performed during wet weather conditions, undercutting the deteriorated soil and replacing with crushed stone, rather than soil fill, may be preferable. We recommend that the contractor smooth-roll exposed subgrades at the end of each work day, limit construction traffic to defined areas, and protect exposed subgrade soils during construction. This is essential for construction during the typically wetter, cooler months of November through March. If soils are rough-graded and not immediately covered by floor slab or pavement base course materials, the contractor should consider covering the exposed subgrades with a sacrificial layer of crushed stone, leave the subgrades approximately 1 foot high, or be prepared to repair/stabilize the subgrades at a later date.

4.1.5 Cut and Fill Slopes Final project slopes should be designed at 3 horizontal to 1 vertical or flatter. The tops and bases of all slopes should be located a minimum of 10 feet from structural limits and a minimum of 5 feet from pavement limits. The fill slopes should be adequately compacted, as outlined in this report, and all slopes should be seeded and maintained after construction. Experience indicates that compaction equipment often has difficulty adequately compacting the face of fill slopes. Therefore, we recommend that fill slopes be overbuilt and cut back to the design geometry, leaving the exposed face well compacted.

4.1.6 Excavations Based on the subsurface information obtained and grading information provided to us, the majority of general site excavation will be in existing fill and residual soils. These soils, as well as newly placed fill, can be excavated using traditional earth moving equipment (e.g., trackhoes, scrapers, bulldozers, etc.). The depth to, and thickness of PWR, rock lenses or seams can vary dramatically in short distances and between boring locations. Therefore, PWR, boulders or bedrock may be encountered between boring locations.

4.1.7 Temporary Excavation Stability For temporary excavations, shoring and bracing or flattening (laying back) of the slopes should be performed to obtain a safe working environment. Excavations should be sloped or shored in accordance with local, state and federal regulations, including OSHA

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(29 CFR Part 1926) excavation trench safety standards. The contractor is usually solely responsible for site safety. This information is provided only as a service and under no circumstances should we be assumed responsible for construction site safety. Based on the plans provided to us, the excavation of the new basement tunnel connection will be within a few feet of Building 4 in some areas, which may require a temporary excavation support system allowing a nearly vertical excavation. Typical temporary excavation support systems include soldier pile with lagging walls, tieback walls, sheetpile walls or soil nail walls. Based on the subsurface conditions and our experience, we anticipate a combination of soldier pile and lagging would be the most cost-effective temporary shoring system if required. If soldier piles are used, it may be necessary to pre-drill them in order to avoid vibrations or disturbance to the existing building caused by driving the piles into place. The information above is provided only as a service and under no circumstances should we be assumed responsible for construction site safety. The contractor is usually solely responsible for site safety.

4.1.8 Temporary Dewatering Based on the soil test borings and anticipated finished floor elevations, a temporary/permanent dewatering system may not be required for development of the subject site; however, measures to dewater basement walls and the proposed cut wall should be provided. Water levels tend to fluctuate with seasonal and climatic variations, as well as with some types of construction operations. Therefore, groundwater may be encountered during construction at depths not indicated by the borings.

4.1.9 Effects of Construction Several aspects of construction at this site could adversely affect the adjacent streets, utilities, and existing facilities. It would be prudent to consider a comprehensive pre-condition survey of existing structures (i.e., buildings) as well as infrastructure such as adjacent streets and utilities. This could provide a baseline for future monitoring as well protection from potential claims. The potential effects should be considered during design and construction such that the adjacent buildings/facilities will be protected. Proper design and special care during construction will be needed to protect the adjoining buildings and streets. Items such as jackhammering, blasting, pile driving and other construction activities can generate vibrations. These vibrations can cause damage to adjacent structures if not properly controlled. Care must be taken to prevent damage of newly placed structures, especially fresh concrete. We recommend that vibration monitoring be performed for structures located nearby during the construction activities that generate a large amount of vibration. This will reduce the potential for large magnitude vibrations and subsequent damage claims. Additionally, while any necessary excavation support system should be designed to limit lateral and vertical deflections, some movement will be occur in order to mobilize the active earth pressures.

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4.1.10 Fill Material and Placement All fill used for site grading operations should consist of a clean (free of organics and debris), low plasticity soil. The proposed fill should have a maximum dry density of at least 90 pounds per cubic foot as determined by a standard Proctor compaction test, ASTM D 698. Based on the proposed plan, we do not anticipate that there will be any cut areas of the site that will be able to provide suitable materials for areas requiring structural fill. Additionally, given that the near-surface materials typically consist of existing high plastic fill materials, we do not recommend that these materials be re-used in structural fill areas of the building. We recommend that an off-site borrow source be determined to supply the structural fill and basement wall backfill needed for the project. The structural fill material should consist of a clean (free of organics and debris), low plasticity soil (Liquid Limit less than 50, Plasticity Index less than 25) classifying as a SM, ML, SP, SW, GW or GP. All fill should be placed in loose lifts not exceeding eight inches in thickness and compacted to a minimum of 95 percent of its standard Proctor maximum dry density, with the final 18 inches below subgrade compacted to at least 98 percent. We recommend that field density tests, including one-point Proctor verification tests, be performed on the fill as it is being placed at a frequency of 1 test per 5,000 square feet per lift in the building and parking areas and one test per lift per 100 linear feet in utility trenches.

5.0 DESIGN RECOMMENDATIONS

5.1 Seismic Design Parameters The proposed structures should be designed to resist possible earthquake effects as determined in accordance with the current applicable building code. Based on Section 1613 of the North Carolina Building Code 2009 Edition (2006 International Building Code with North Carolina Amendments), results of the field exploration program and our experience in the project area indicate the average N-values in the soils underlying the proposed building to be greater than 50 in the top 100 feet below the proposed foundation bearing elevations. This corresponds to a Seismic Site Class C. Based on a Seismic Site Class C, the five percent damped design spectral response acceleration at short periods, SDS, and at 1 second period, SD1, were determined to be 0.208g and 0.107g, respectively.

5.2 Foundation Support – Basement/Tunnel Foundations Based on results of the field exploration and the proposed foundation bearing elevations of 707 feet (MSL) for the basement foundations, we recommend that the basement foundations be designed as shallow spread footings bearing on the residual silty sands encountered in the soil test borings. A net allowable bearing pressure of up to 5,000 pounds per square foot (psf) can be used for design of the basement foundations bearing on the low-plasticity residual soils.

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Minimum wall and column footing dimensions of 16 and 24 inches, respectively, should be maintained to reduce the possibility of a localized, punching-type shear failure. Exterior foundations and foundations in unheated areas should be designed to bear at least 12 inches below finished grade for frost protection and protective embedment. The bottom of all footing excavations should be evaluated by the project geotechnical engineer, an experienced staff professional, or a senior soil technician working under the direction of the geotechnical engineer using hand auger borings supplemented with Dynamic Cone Penetrometer (DCP) testing to gauge the consistency of the subgrade soils. Low consistency/relative density soils that appear unstable or exhibit DCP blow counts less than required to achieve the design bearing pressure should be excavated until adequate bearing materials are encountered. The resulting excavations may be backfilled to the design foundation bearing level with a suitable structural fill material. These observations will help assess the suitability of the soil for foundation support and confirm the conditions upon which our recommendations are based. The anticipated subgrade materials can be sensitive to moisture variations; therefore, foundation excavations should be opened for a minimum amount of time, particularly during inclement weather. Soils exposed to moisture variations may become highly disturbed and undercutting may be required prior to placing foundations on these materials. If the excavation must remain open overnight or if rainfall becomes imminent while the bearing soils are exposed, we recommend that a 2 to 4-inch thick “mud-mat” of lean (2000 psi) concrete be placed on the bearing soils before placement of reinforcing steel.

5.3 Foundation Support – At-Grade Foundations As previously discussed, all of the borings encountered existing fill materials to depths ranging from 3 to 10 feet below existing grades. Once the design subgrade elevation is reached, we expect that areas of poorly compacted fill and highly plastic clays will be present at foundations bearing elevations. The fill soils typically consisted of silty clays, clayey silts and sandy silts with N-values ranging from 3 to 18 blows per foot (bpf). Based on the anticipated column loads for the new building, bearing the new foundations on the existing fill materials would result in settlements in excess of 1 inch and differential settlements greater than one-half inch. The inherent shrink/swell potential of the moderate to highly plastic fill soils also adds the potential for future foundation issues. While undercutting all of the fill soils and replacing with properly compacted structural fill is an option, we do not feel that it would be cost effective. We recommend that an alternative ground improvement or deep foundation system be used for support of the new structure.

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5.3.1 Shallow Foundations with Geopiers Based on the magnitude of the anticipated loads and the existing on-site soils settlement estimates were considered excessive for the new building. In order to reduce the settlement potential of the foundation soils, the stiffness of these soils can be improved allowing the building to then be supported on a traditional shallow spread footing system that bears on these improved foundation soils. Several ground improvement options could be considered; however, we anticipate the most economical system to consist of a properly designed aggregate pier system. This system of piers will provide an increase in stiffness beneath the individual footings, thereby reducing settlements and allowing for increased bearing capacities. A properly designed short aggregate pier system, such as the Geopier® Intermediate Foundation System, is made up of very stiff, densely compacted aggregate piers, approximately 30 to 36 inches in diameter. The piers are constructed by forming a cavity in the soil matrix by drilling or similar excavation methods. The soil at the bottom of the cavity is pre-stressed and densified using a large tamper. Once the soil at the bottom of the cavity is pre-stressed, well-graded aggregate base stone is placed in the hole in 18-inch lifts and compacted, using a high energy tamping system until the hole is filled. The building's foundations then rest on the pier system. We anticipate that allowable bearing pressures in the range of 7,000 to 8,000 psf can be achieved with pier elements installed to depths of about 10 to 15 feet below foundations. As these systems are proprietary, their design and installation is typically performed under a design-build contract. For example, the Geopier foundation system design and installation is provided by GeoStructures, Inc. We recommend that you contact GeoStructures or other qualified contractor to further review and analyze the subsurface data for this site, as well as the design structural loads for the project such that they can provide a cost estimate for Geopier installation. The estimate should include the cost to perform a modulus load test on a Geopier element at the project site. The load test should be performed to confirm the amount of compression that an individual Geopier element will experience at the maximum theoretical stress. Tests should be monitored full time by the Owner’s geotechnical consultant. At least one load test should be performed on a Geopier element located in the most critical area of the site. Loading of the test pier should be conducted up to 150% of the maximum theoretical stress to which the Geopier elements will be subjected. At 100% of the maximum theoretical stress, settlement of the footing supported by the Geopier element should not exceed 1 inch. We recommend that the Geopier installation and the installer’s quality control (QC) program be monitored full time by the Owner’s geotechnical consultant. The QC program includes conducting Dynamic Cone Penetration (DCP) testing, verification of bottom stabilization, and measurement of drill depths and aggregate lift thickness. These items should be documented for each Geopier element installed to provide complete record of Geopier foundation quality.

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5.3.2 Auger-Cast Piles As an option to the use of a ground improvement system such as the Geopiers discussed above, the building foundations could be supported on a deep foundation system of auger-cast piles. We recommend 16-inch diameter Continuous Flight Auger (CFA) piles designed for a 50-ton working load. CFA piles are installed by advancing a continuous flight, hollow stem auger suspended from a crane boom to the design pile tip elevation. Grout is pumped down the auger hollow stem under pressure as the auger is withdrawn. A minimum center to center pile spacing of 3 diameters is recommended. During construction, auger cast-in-place piles should not be installed within 6 pile diameters center to center of piles filled with grout less than 12 hours old. Pile reinforcing should be designed to comply with Section 1810 for the North Carolina State Building Code (2009). Pile reinforcing steel is installed in CFA piles immediately after withdrawal of the auger while grout is fluid. Allowable uplift loads on the order of 1.5 kips per foot of pile or more can be developed (excluding upper 5 feet of pile length) with a 16-inch diameter pile, provided the length relied upon to resist uplift is adequately reinforced. Higher uplift resistance may be available. Cages should have a 2-1/2 inch clear distance on all sides. To the extent possible, reinforcing cages should not have outward bent bars at the top as this significantly hinders removal of auger cuttings from adjacent piles. The soil test borings typically encountered uniform, high consistency sands below an elevation of 707 feet (MSL). Layers of PWR were encountered at various depths. The Standard Penetration Test (SPT) values in this stratum ranged from 17 to 82 blows per foot. We recommend installation of CFA piles to a tip elevation of 687 feet (MSL). This termination criteria is intended to achieve approximately 20-feet of penetration into the dense residual silty sands to achieve the design skin friction. The grade from which auger cast-in-place piles are installed is a construction means and methods issue. Contractors generally prefer an installation grade above the top of reinforcing steel. We recommend equipment with a continuous flight, hollow stem auger developing a minimum of 30,000 foot-pounds of torque and a minimum verifiable downward force of 5,000 pounds. While not expected, CFA refusal above the recommended pile tip elevation may be encountered. Refusal should be defined as an auger penetration rate of 12-inches per minute or less. Provided refusal is interpreted by the Geotechnical Engineer to be in PWR, no reduction in design pile capacity is required. Grout injection and withdrawal techniques are critical to developing high capacity CFA piles. Piles for this project will be installed significantly below groundwater. The suction associated with auger withdrawal and hydrostatic pressure associated with the depth below the groundwater level will cause the augured hole to collapse unless it is balanced by grout pressure during auger withdrawal. A grout pressure head of at least 10 feet of grout above the injection point or above the water level, whichever is higher,

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should be maintained at all times during auger withdrawal. The soil filled augers should be withdrawn during grouting at a rate less than the grout pumping rate. A calibrated positive displacement pump capable of measuring grout volumes pumped and developing a minimum pressure of 350 psi at the pump should be used. Grout volumes should be measured and determined to exceed the theoretical grout volume required to fill the augured hole. If grout pressure is lost, or the grout volume is less than the theoretical grout volume, the pile should be re-drilled to the original depth and re-grouted. If grout pressure is momentarily interrupted, the pile should be augured 5 feet below the interruption and re-grouted. We recommend a 4,000 psi minimum grout strength. The North Carolina State Building Code requires the following quality control measures:

• Performance of a pile load test, • Installation of pile foundations “under the direct supervision of a registered design

professional knowledgeable in the field of soil mechanics and pile foundations,” including certain documentation requirements, and that

• Pile installation in accordance with approved construction plans be certified by a registered design professional.

Compliance with the above requires that installation and testing of CFA piles be monitored by engineering technicians reporting to the Geotechnical Engineer of Record. In our opinion, subsurface conditions in the study area are sufficiently uniform that only one pile compressive load test is necessary. We understand that the piles will not be required to resist uplift loads, and do not recommend performance of an uplift pile load test. We recommend that the compressive pile capacity load test be performed in accordance with ASTM D-1143 to a minimum of 2.5 times the pile working load. Pile capacities are expected to be developed by side friction and end bearing. These materials are not expected to exhibit significant creep; therefore, test loads may be applied in accordance with ASTM 1143, Section 6.3, Quick Load Test for Individual Piles.

5.4 Settlement Based on the general stratigraphy in the building area, our experience with similar projects, the anticipated magnitude of the building loads, and anticipated site grades, the total settlement potential for the building should be less than one inch with differential settlements approximately one half the total settlement. This conclusion is contingent upon compliance with the site preparation, fill placement and foundation recommendations outlined in this report.

5.5 Floor Slabs Existing fill soils are anticipated at subgrade elevations for the building pad. Further evaluation of existing fill soils via proofrolling, hand auger borings, or additional test pits should be performed during construction. Subgrades that are unstable, excessively wet, plastic, or contain deleterious inclusions may require additional, isolated undercutting and backfilling with structural fill.

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Ground-level floor slabs may be supported directly on properly compacted fill or stable existing fill soils. A 4-inch-thick layer of stone (NCDOT No. 57, No. 67 or ABC) should be provided beneath all building floor slabs to prevent capillary rise and a damp slab condition for occupied, heated spaces with slab-on-grade floors. The floor slabs should be designed to resist the anticipated dead and live loads. We recommend that the floor slabs be designed using a modulus of subgrade reaction (k) of 150 pounds per cubic inch (pci). We recommend that construction joints in the slabs include dowels to improve load transfer across the joints and to reduce the potential for differential vertical displacement across the joints. It is anticipated that the rutting from construction traffic during installation of foundations for the new building will damage the subgrade of the proposed building pad. In order to help prevent the deterioration of the building pad slab, we recommend that a layer of sacrificial ABC Stone be placed across the pad. This will assist with foundation construction traffic as well as keep the subgrade materials form being damaged and reduce the amount of repairs once construction of the slab begins. Immediately prior to constructing the floor slabs, we recommend that the areas be proofrolled to detect any softened, loosened or disturbed areas that may have been exposed to wet weather or construction traffic. Areas that are found to be disturbed or indicate pumping action during the proofrolling should be undercut and replaced with adequately compacted structural fill. This proofrolling should be observed by a staff professional or a senior soil technician under his/her direction. Proofrolling procedures are discussed in previous sections of this report.

5.6 Basement Walls Below grade walls must be capable of resisting lateral earth pressures imposed on them. Lateral earth pressures to be resisted by the walls will be partially dependent upon the method of construction. Assuming the walls are relatively rigid and structurally braced against rotation, they should be designed for a condition approaching the "at-rest" lateral pressure. However, in the event the walls are free to deflect during backfilling, as for any exterior walls that are not restrained or rigidly braced and temporary shoring/bracing, the "active" pressure conditions will be applicable for design. The following lateral earth pressure parameters are recommended for design and are based on wall backfill consisting of off-site structural fill materials. The on-site soils are not suitable for re-use as backfill against the basement walls. These parameters assume a level backfill, a frictionless wall, and no hydrostatic pressure.

On-site backfill

Internal Friction Angle (Φ) 28° Moist Unit Weight (pcf) 130 pcf At-rest Earth Pressure (Ko) 0.53 Active Earth Pressure (Ka) 0.36 Passive Earth Pressure (Kp) 2.76

14


The above parameters do not include the influence of foundations located in or adjacent to wall backfill and assumes that backfill is level. Surcharge loads (e.g., nearby structures, sloping backfill) should be added to the design pressure. The wall backfill should be compacted to at least 95 percent of the standard Proctor’s maximum dry density (ASTM D 698). When compacting the backfill, self-propelled compaction equipment should not be used within 5 ft of the structure walls. We caution that operating compaction equipment directly behind the retaining structures can create lateral earth pressures far in excess of those recommended for design. Therefore, bracing of the walls may be needed during backfilling operations. Drainage should be provided behind the walls to help reduce build-up of hydrostatic forces. A free draining granular material or manufactured geo-composite product such as Miradrain 6000, or approved equivalent, should be placed behind the walls an should be designed to positively gravity drain away from the structure via foundation drains that could connect with the storm drain system or dewatering system. The basement walls of the structure should be damproofed in accordance with the North Carolina Building Code. When backfilling against the walls, care should be taken to prevent the backfill from being over-compacted, since this could result in development of excessive lateral pressures. In the same regard, heavy equipment should not be used for compaction of the backfill or allowed to operate adjacent to the walls.

5.7 Corrosion Potential of Underground Facilities A split-spoon sample from Boring B-5 was selected and tested by an independent laboratory for pH and resistivity (specific conductance). The pH test indicated a pH of 4.3, and the resistivity test result indicates a resistivity of 2040 ohm/cm. The results are included at the end of this report. Based on our experience, soils with pH greater than 5.5 are typically considered to have a slight degree of aggressiveness with regard to corrosion potential to concrete and steel. Soils with pH lower than 4.5 are considered to have a very severe degree of corrosion potential. The pH test result falls in the corrosive range. Various studies have related the resistivity of the soil to the corrosivity as a means of predicting corrosion potential. The following table is taken from the publication “Underground Corrosion” prepared by the American Society for Testing and Materials, Bulletin STP-741.

Soil Corrosivity versus Resistivity

Soil Corrosivity Soil Resistivity (ohm-cm) Very corrosive 0 to 2,000

Corrosive 2,000 to 5,000 Moderately corrosive 5,000 to 10,000

Mildly corrosive 10,000 to 25,000 Relatively less corrosive 25,000 to 50,000

Progressively non-corrosive 50,000 to 100,000

15


Although a number of other factors are important, apparent resistivity is considered a reliable indicator of corrosivity in soil. Therefore, the near-surface fill soils at the site appear to be relatively corrosive based on resistivity test results. However, this is based on a single sample tested. If the corrosivity of the near-surface soils will adversely affect construction costs due to material types for utilties and foundations, it may be prudent to test additional samples of the near-surface materials. To supplement testing of on-site soils for corrosion potential, samples were tested for sulfates and chloride content. A sulfate (SO4) value of 261 ppm and Chloride (CL) value of 139 ppm were obtained. Based on these results the corrosion potential is high. We recommend that the cement type be Portland Type II. In general, ACI recommends that a minimum concrete protective covering for reinforcement should be three inches for concrete deposited against the ground.

5.8 Pavements Existing fill soils are anticipated at pavement subgrades in the western and eastern portions of the site. Further evaluation of existing fill soils via proofrolling, hand auger borings, or additional test pits should be performed during construction. Subgrades that are unstable, excessively wet, plastic, or contain deleterious inclusions may require additional, isolated undercutting. The use of subgrade stabilization measures, such as the use of geotextile grids may also be used. We recommend the following pavement thicknesses and configurations over the prepared soil subgrades:

Thicknesses (inches) Pavement Type Material

Light-Duty Heavy-DutyConcrete

(4,000 psi) 5 6 Rigid

Aggregate Base Course (ABC) (Optional) 6 6

Superpave Asphalt Surface Course Type SF 9.5A 2.5 1

Superpave Asphalt Intermediate Course

Type I 19.0B N/A 2.5 Flexible

Aggregate Base Course (ABC) 8 8

The light-duty pavement section should be used for parking areas and light travel lanes. Heavy-duty pavements should be used for entrances and exits, access roads, driveways, and truck lanes. Heavy-duty concrete pavement is typically used in areas in front of loading docks and dumpsters.

16


The early placement of the graded aggregate base course will minimize the deterioration of the prepared soil subgrades. However, some loss of graded aggregate due to rutting and surface contamination may occur prior to final asphalt or concrete paving. Some infilling and re-grading of the graded aggregate in conjunction with sweeping with a wire broom may be required. For rigid pavements, the graded aggregate base course is optional, but can be beneficial in protecting the subgrade prior to paving and providing a stiffer working surface during paving. Pavements and bases should be constructed in general accordance with the guidelines of the current edition of the North Carolina Department of Transportation’s “Standard Specifications for Roads and Structures.” Materials, weather limitations, placement, and compaction are specified under appropriate sections of this publication. Prevention of infiltration of water into the subgrade is essential for the successful performance of any pavement. Both the subgrade and the pavement surface should be sloped to promote surface drainage away from the pavement structure. Also, drains should be provided to prevent landscape irrigation from saturating pavement subgrades.

6.0 LIMITATIONS OF REPORT

The boring locations given in this report should be considered accurate only to the degree implied by the methods used to determine them. The boring logs represent our interpretation of the subsurface conditions based on the field logs, and visual examinations of samples by a staff professional or technician, in addition to tests of the field samples. The lines designating the interfaces between various strata may be gradual. The generalized subsurface strata and profiles described in this report are intended to convey trends in subsurface conditions. The boundaries between strata are approximate and idealized. They have been developed by interpretations of widely-spaced borings. Therefore, actual subsurface conditions may vary from those given between test locations. Groundwater levels have been measured or inferred in the borings at the times and under the conditions stated on the exploration logs in this report. Changes in the groundwater conditions may occur due to variations in rainfall, evaporation, construction activity, surface water runoff, and other site specific factors. Our geotechnical services include storing the samples collected and making them available for inspection for 90 days. The samples are then discarded unless our client requests otherwise. The assessment of site environmental conditions and the determination of contaminants in the soil, rock, surface water or groundwater of the site were beyond the scope of this geotechnical study.

17


18

The recommendations provided in this report are based on our understanding of the project information given in this report and on our interpretation of the surface and subsurface data collected. We have made our recommendations based on our experience with similar subsurface conditions and similar projects. The recommendations apply to the specific project discussed in this report; therefore, any changes in the project information should be provided to us so we may review our conclusions and recommendations and make any appropriate modifications. S&ME should be retained for a general review of the design drawings and specifications to verify that geotechnical recommendations are properly interpreted and implemented. Regardless of the thoroughness of a geotechnical study, there is always a possibility that subsurface conditions will be different from those at boring locations, that conditions will not be as anticipated by the designers or contractors, or that the construction process will alter soil conditions. Therefore, qualified geotechnical personnel should observe construction to confirm that the conditions indicated by the geotechnical borings actually exist. We recommend the owner retain S&ME for this service since we are already familiar with the project, the subsurface conditions at the site, and the intent of the recommendations and design. This report has been prepared for the exclusive use of the client for specific application to the subject project and project site. It has been prepared in accordance with generally accepted geotechnical engineering practice for specific application to this project. The conclusions and recommendations contained in this report are based upon applicable standards of our practice in this geographic area at the time this report was prepared. No other warranty, expressed or implied, is made.

SITE VICINITY MAPHefner VAMCSalisbury, NCDATE: 2/15/10

FIGURE NO.

1

Proj No:1351-10-004

PROPOSED SITE

SCALE: NTS

675

680

685

690

695

700

705

710

715

720

0 20 40 60 80 100 120 140 160 180

JOB NO:

DATE:

N = Standard Penetration Test resistance value (blows per foot). The depicted stratigraphy is shown for illustrative purposes only. The actual subsurface conditions will vary between boring locations.

Project: Hefner VAMC Expansion

Location: Salisbury, North Carolina

CH, High Plasticity Clay

CL, Low Plasticity Clay

SC, Clayey Sand

Asphalt

Aggregate Base Course

Partially Weathered Rock

APPROXIMATE DISTANCE ALONG PROFILE (feet)

Fill

Topsoil

SM, Silty Sand

ML, Low Plasticity Silt

1351-10-004

2/12/10

EL

EV

AT

ION

(fe

et-M

SL

)

FIGURE NO.

3

7

5

9

12

29

26

27

B-01

BT @ 25

N10

8

8

9

23

38

33

35

B-02

BT @ 30

N

17

11

9

9

37

51

38

82

53

50/3"

B-03

BT @ 40

N

5

4

9

54

27

59

31

37

B-04

BT @ 30

N6

6

8

16

32

25

24

27

B-05

BT @ 30

N

5

3

6

13

56

44

50/5"

50/4"

48

71

B-06A

BT @ 40

N

8

13

18

20

30

29

32

37

B-07

BT @ 30

N

18

8

9

34

31

31

50/5"

50/5"

B-08

BT @ 30

N

5

15

13

17

37

36

36

76

B-09

BT @ 30

N

16

31

47

40

29

36

50/5.5"

B-10

BT @ 25

N

8

4

7

B-11

BT @ 7.5

N

18

16

14

16

B-12

BT @ 10

N

Topsoil/Rootmat

FILL: Firm Tan Fine Sandy SILT (ML)

FILL: Firm to Stiff Orange Red Silty CLAY (CH)

RESIDUUM: Medium Dense to Dense Tan BrownSilty Fine SAND (SM)

Boring terminated at 25 feet. Boring dry andbackfilled at termination.

Depth measurements are shown to illustrate thegeneral arrangements of soil types encountered atthe boring location. Do not use depthmeasurements for determination of distances orquantities.

7

5

9

12

29

26

27

STANDARD PENETRATION TEST DATA

(blows/ft)

60WA

TE

R L

EV

EL

10


Hefner VAMC ExpansionSalisbury, North Carolina

PROJECT:

20

WATER LEVEL:

80

BORING LOG B-01

SA

MP

LE N

O.

SA

MP

LE T

YP

E

712.0

707.0

702.0

697.0

692.0

ELEVATION: 717.0

BORING DEPTH: 25.0

MATERIAL DESCRIPTION

ELE

VA

TIO

N

(fee

t)

GR

AP

HIC

LOG

N V

ALU

E

5

10

15

20

25

DE

PT

H

(fee

t)

DRILL RIG: D-50

Dry on 1/27/10

NOTES: Standard Penetration Testingperformed with Autohammer.

Elevations shown are approximate and have notbeen surveyed.

DATE DRILLED: 1/27/10

DRILLING METHOD: 3¼" H.S.A.

LOGGED BY: B. McKean

DRILLER: Lynn

30

Page 1 of 1NOTES:

1.

2.

3.

4.

THIS LOG IS ONLY A PORTION OF A REPORT PREPARED FOR THE NAMEDPROJECT AND MUST ONLY BE USED TOGETHER WITH THAT REPORT.

BORING, SAMPLING AND PENETRATION TEST DATA IN GENERALACCORDANCE WITH ASTM D-1586.

STRATIFICATION AND GROUNDWATER DEPTHS ARE NOT EXACT.

WATER LEVEL IS AT TIME OF EXPLORATION AND WILL VARY.

BO

RIN

G L

OG

10-

004

HE

FN

ER

VA

.GP

J S

&M

E.G

DT

2/1

1/10

Grass/Rootmat (4 inches)

FILL: Stiff to Firm Gray Red and Brown Fine toMedium Sandy Silty CLAY (CL)

FILL: Firm Brown Gray Silty Clayey Fine toMedium SAND (SC) (wet)

RESIDUUM: Stiff Tan Yellow Fine Sandy SILT(ML)

Medium Dense to Dense Tan Brown and YellowSilty Fine to Medium SAND (SM)

10

8

8

9

23

38

33

35


(blows/ft)

60WA

TE

R L

EV

EL

10



PROJECT:

20

WATER LEVEL:

80

BORING LOG B-02

SA

MP

LE N

O.

SA

MP

LE T

YP

E

714.0

709.0

704.0

699.0

694.0

689.0

ELEVATION: 719.0

BORING DEPTH: 30.0


ELE

VA

TIO

N

(fee

t)

GR

AP

HIC

LOG

N V

ALU

E

5

10

15

20

25

30

DE

PT

H

(fee

t)

DRILL RIG: D-50

Dry on 1/27/10






DRILLER: Lynn

30

Page 1 of 2NOTES:

1.

2.

3.

4.





BO

RIN

G L

OG

10-

004

HE

FN

ER

VA

.GP

J S

&M

E.G

DT

2/1

1/10




(blows/ft)

60WA

TE

R L

EV

EL

10



PROJECT:

20

WATER LEVEL:

80

BORING LOG B-02

SA

MP

LE N

O.

SA

MP

LE T

YP

E

ELEVATION: 719.0

BORING DEPTH: 30.0


ELE

VA

TIO

N

(fee

t)

GR

AP

HIC

LOG

N V

ALU

E

DE

PT

H

(fee

t)

DRILL RIG: D-50

Dry on 1/27/10






DRILLER: Lynn

30

Page 2 of 2NOTES:

1.

2.

3.

4.





BO

RIN

G L

OG

10-

004

HE

FN

ER

VA

.GP

J S

&M

E.G

DT

2/1

1/10

Asphalt (4 inches)

ABC Stone (6 inches)

FILL: Very Stiff to Stiff Orange Red and BrownSilty CLAY (CH)

RESIDUUM: Stiff Tan Brown Clayey Fine SandySILT (ML)

Dense to Very Dense Tan Brown and Gray SiltyFine to Medium SAND (SM)

17

11

9

9

37

51

38

82


(blows/ft)

60WA

TE

R L

EV

EL

10



PROJECT:

20

WATER LEVEL:

80

BORING LOG B-03

SA

MP

LE N

O.

SA

MP

LE T

YP

E

713.0

708.0

703.0

698.0

693.0

688.0

ELEVATION: 718.0

BORING DEPTH: 40.0


ELE

VA

TIO

N

(fee

t)

GR

AP

HIC

LOG

N V

ALU

E

5

10

15

20

25

30

DE

PT

H

(fee

t)

DRILL RIG: D-50

Dry on 1/26/10






DRILLER: Lynn

30

Page 1 of 2NOTES:

1.

2.

3.

4.





BO

RIN

G L

OG

10-

004

HE

FN

ER

VA

.GP

J S

&M

E.G

DT

2/1

1/10

Dense to Very Dense Tan Brown and Gray SiltyFine to Medium SAND (SM)

(continued)

PARTIALLY WEATHERED ROCK: WhenSampled, becomes Tan Brown Silty Fine toMedium SAND

Boring terminated at 39.3 feet. Boring dry andbackfilled at termination.


53

50/3"


(blows/ft)

60WA

TE

R L

EV

EL

10



PROJECT:

20

WATER LEVEL:

80

BORING LOG B-03

SA

MP

LE N

O.

SA

MP

LE T

YP

E

683.0

678.0

ELEVATION: 718.0

BORING DEPTH: 40.0


ELE

VA

TIO

N

(fee

t)

GR

AP

HIC

LOG

N V

ALU

E

35

40

DE

PT

H

(fee

t)

DRILL RIG: D-50

Dry on 1/26/10






DRILLER: Lynn

30

Page 2 of 2NOTES:

1.

2.

3.

4.





BO

RIN

G L

OG

10-

004

HE

FN

ER

VA

.GP

J S

&M

E.G

DT

2/1

1/10

>>

Topsoil/Rootmat

FILL: Firm to Soft Red Orange and Brown FineSandy Silty CLAY (CH) mixed with Sandy Siltseams

FILL: Stiff Orange Red Brown Silty CLAY (CL)

RESIDUUM: Very Dense Tan White Silty Fine toMedium SAND (SM)

Very Dense to Dense Tan Brown to Olive BrownSilty Fine SAND (SM)

5

4

9

54

27

59

31

37


(blows/ft)

60WA

TE

R L

EV

EL

10



PROJECT:

20

WATER LEVEL:

80

BORING LOG B-04

SA

MP

LE N

O.

SA

MP

LE T

YP

E

710.0

705.0

700.0

695.0

690.0

685.0

ELEVATION: 715.0

BORING DEPTH: 30.0


ELE

VA

TIO

N

(fee

t)

GR

AP

HIC

LOG

N V

ALU

E

5

10

15

20

25

30

DE

PT

H

(fee

t)

DRILL RIG: D-50

Dry on 1/28/10






DRILLER: Lynn

30

Page 1 of 2NOTES:

1.

2.

3.

4.





BO

RIN

G L

OG

10-

004

HE

FN

ER

VA

.GP

J S

&M

E.G

DT

2/1

1/10




(blows/ft)

60WA

TE

R L

EV

EL

10



PROJECT:

20

WATER LEVEL:

80

BORING LOG B-04

SA

MP

LE N

O.

SA

MP

LE T

YP

E

ELEVATION: 715.0

BORING DEPTH: 30.0


ELE

VA

TIO

N

(fee

t)

GR

AP

HIC

LOG

N V

ALU

E

DE

PT

H

(fee

t)

DRILL RIG: D-50

Dry on 1/28/10






DRILLER: Lynn

30

Page 2 of 2NOTES:

1.

2.

3.

4.





BO

RIN

G L

OG

10-

004

HE

FN

ER

VA

.GP

J S

&M

E.G

DT

2/1

1/10


FILL: Firm Red Orange Silty CLAY (CH)

RESIDUUM: Medium Dense to Dense White Grayto Tan Brown Silty Fine SAND (SM)

6

6

8

16

32

25

24

27


(blows/ft)

60WA

TE

R L

EV

EL

10



PROJECT:

20

WATER LEVEL:

80

BORING LOG B-05

SA

MP

LE N

O.

SA

MP

LE T

YP

E

712.0

707.0

702.0

697.0

692.0

687.0

ELEVATION: 717.0

BORING DEPTH: 30.0


ELE

VA

TIO

N

(fee

t)

GR

AP

HIC

LOG

N V

ALU

E

5

10

15

20

25

30

DE

PT

H

(fee

t)

DRILL RIG: D-50

Dry on 1/27/10






DRILLER: Lynn

30

Page 1 of 2NOTES:

1.

2.

3.

4.





BO

RIN

G L

OG

10-

004

HE

FN

ER

VA

.GP

J S

&M

E.G

DT

2/1

1/10




(blows/ft)

60WA

TE

R L

EV

EL

10



PROJECT:

20

WATER LEVEL:

80

BORING LOG B-05

SA

MP

LE N

O.

SA

MP

LE T

YP

E

ELEVATION: 717.0

BORING DEPTH: 30.0


ELE

VA

TIO

N

(fee

t)

GR

AP

HIC

LOG

N V

ALU

E

DE

PT

H

(fee

t)

DRILL RIG: D-50

Dry on 1/27/10






DRILLER: Lynn

30

Page 2 of 2NOTES:

1.

2.

3.

4.





BO

RIN

G L

OG

10-

004

HE

FN

ER

VA

.GP

J S

&M

E.G

DT

2/1

1/10

Grass/Roots/Topsoil (4 inches)

FILL: Firm Brown Fine Sandy Silty CALY (CH)

Concrete obtuction encountered at 4 feet. Boringoffset 6 feet north to B-6A.

Boring backfilled at termination.

7

50/2"


(blows/ft)

60WA

TE

R L

EV

EL

10



PROJECT:

20

WATER LEVEL:

80

BORING LOG B-06

SA

MP

LE N

O.

SA

MP

LE T

YP

E

ELEVATION: 717.0

BORING DEPTH: 4.0


ELE

VA

TIO

N

(fee

t)

GR

AP

HIC

LOG

N V

ALU

E

DE

PT

H

(fee

t)

DRILL RIG: D-50

Dry on 1/27/10






DRILLER: Lynn

30

Page 1 of 1NOTES:

1.

2.

3.

4.





BO

RIN

G L

OG

10-

004

HE

FN

ER

VA

.GP

J S

&M

E.G

DT

2/1

1/10

>>

Grass/Topsoil (4 inches)

FILL: Soft to Firm Red Orange Brown Fine SandySilty CLAY (CH)

RESIDUUM: Stiff Gray Fine Sandy SILT (ML)

Dense to Very Dense Gray and Brown Silty Fine toMedium SAND (SM)

PARTIALLY WEATHERED ROCK: WhenSampled, becomes Black and Tan Silty Fine toMedium SAND

5

3

6

13

56

44

50/5"

50/4"


(blows/ft)

60WA

TE

R L

EV

EL

10



PROJECT:

20

WATER LEVEL:

80

BORING LOG B-06A

SA

MP

LE N

O.

SA

MP

LE T

YP

E

712.0

707.0

702.0

697.0

692.0

687.0

ELEVATION: 717.0

BORING DEPTH: 40.0


ELE

VA

TIO

N

(fee

t)

GR

AP

HIC

LOG

N V

ALU

E

5

10

15

20

25

30

DE

PT

H

(fee

t)

DRILL RIG: D-50

Dry on 1/28/10






DRILLER: Lynn

30

Page 1 of 2NOTES:

1.

2.

3.

4.





BO

RIN

G L

OG

10-

004

HE

FN

ER

VA

.GP

J S

&M

E.G

DT

2/1

1/10

>>

>>

RESIDDUM: Dense to Very Dense Tan andBrown Silty Fine to Medium SAND (SM)



48

71


(blows/ft)

60WA

TE

R L

EV

EL

10



PROJECT:

20

WATER LEVEL:

80

BORING LOG B-06A

SA

MP

LE N

O.

SA

MP

LE T

YP

E

682.0

677.0

ELEVATION: 717.0

BORING DEPTH: 40.0


ELE

VA

TIO

N

(fee

t)

GR

AP

HIC

LOG

N V

ALU

E

35

40

DE

PT

H

(fee

t)

DRILL RIG: D-50

Dry on 1/28/10






DRILLER: Lynn

30

Page 2 of 2NOTES:

1.

2.

3.

4.





BO

RIN

G L

OG

10-

004

HE

FN

ER

VA

.GP

J S

&M

E.G

DT

2/1

1/10

Grass and Topsoil (4 inches)

FILL: Loose to Medium Dense Gray Silty Fine toMedium SAND (SM)

FILL: Very Stiff Gray Brown Silty Clayey Fine toMedium SAND (SC)

RESIDUUM: Medium Dense to Dense Tan Brownand Gray Silty Fine to Medium SAND (SM)

8

13

18

20

30

29

32

37


(blows/ft)

60WA

TE

R L

EV

EL

10



PROJECT:

20

WATER LEVEL:

80

BORING LOG B-07

SA

MP

LE N

O.

SA

MP

LE T

YP

E

711.0

706.0

701.0

696.0

691.0

686.0

ELEVATION: 716.0

BORING DEPTH: 30.0


ELE

VA

TIO

N

(fee

t)

GR

AP

HIC

LOG

N V

ALU

E

5

10

15

20

25

30

DE

PT

H

(fee

t)

DRILL RIG: D-50

Dry on 1/27/10






DRILLER: Lynn

30

Page 1 of 2NOTES:

1.

2.

3.

4.





BO

RIN

G L

OG

10-

004

HE

FN

ER

VA

.GP

J S

&M

E.G

DT

2/1

1/10




(blows/ft)

60WA

TE

R L

EV

EL

10



PROJECT:

20

WATER LEVEL:

80

BORING LOG B-07

SA

MP

LE N

O.

SA

MP

LE T

YP

E

ELEVATION: 716.0

BORING DEPTH: 30.0


ELE

VA

TIO

N

(fee

t)

GR

AP

HIC

LOG

N V

ALU

E

DE

PT

H

(fee

t)

DRILL RIG: D-50

Dry on 1/27/10






DRILLER: Lynn

30

Page 2 of 2NOTES:

1.

2.

3.

4.





BO

RIN

G L

OG

10-

004

HE

FN

ER

VA

.GP

J S

&M

E.G

DT

2/1

1/10

Asphalt (4 inches)


FILL: Medium Dense Tan Gray Silty Fine toMedium SAND (SM)

FILL: Firm Red Orange and Tan Clayey SILT(ML)

RESIDUUM: Stiff Tan Yellow Clayey Fine SandySILT (ML)

Dense Olive Brown and Gray Silty Fine to MediumSAND (SM)

PARTIALLY WEATHERED ROCK: WhenSampled, becomes Brown Tan Silty Fine toMedium SAND

18

8

9

34

31

31

50/5"

50/5"


(blows/ft)

60WA

TE

R L

EV

EL

10



PROJECT:

20

WATER LEVEL:

80

BORING LOG B-08

SA

MP

LE N

O.

SA

MP

LE T

YP

E

711.0

706.0

701.0

696.0

691.0

686.0

ELEVATION: 716.0

BORING DEPTH: 30.0


ELE

VA

TIO

N

(fee

t)

GR

AP

HIC

LOG

N V

ALU

E

5

10

15

20

25

30

DE

PT

H

(fee

t)

DRILL RIG: D-50

Dry on 1/27/10






DRILLER: Lynn

30

Page 1 of 2NOTES:

1.

2.

3.

4.





BO

RIN

G L

OG

10-

004

HE

FN

ER

VA

.GP

J S

&M

E.G

DT

2/1

1/10

>>

>>




(blows/ft)

60WA

TE

R L

EV

EL

10



PROJECT:

20

WATER LEVEL:

80

BORING LOG B-08

SA

MP

LE N

O.

SA

MP

LE T

YP

E

ELEVATION: 716.0

BORING DEPTH: 30.0


ELE

VA

TIO

N

(fee

t)

GR

AP

HIC

LOG

N V

ALU

E

DE

PT

H

(fee

t)

DRILL RIG: D-50

Dry on 1/27/10






DRILLER: Lynn

30

Page 2 of 2NOTES:

1.

2.

3.

4.





BO

RIN

G L

OG

10-

004

HE

FN

ER

VA

.GP

J S

&M

E.G

DT

2/1

1/10

Topsoil/Rootmat

FILL: Firm Red Orange Silty CLAY (CH) with graysandy silt seams

FILL: Stiff Gray Fine Sandy Clayey SILT (ML)

RESIDUUM: Very Stiff to Stiff Gray Fine SandySILT (ML)

Dense White Silty Fine to Coarse SAND (SM) withweathered rock fragments

Hard gray Fine to Medium Sandy SILT (ML)

Very Dense Tan White Silty Fine to Medium SAND(SM)

5

15

13

17

37

36

36

76


(blows/ft)

60WA

TE

R L

EV

EL

10



PROJECT:

20

WATER LEVEL:

80

BORING LOG B-09

SA

MP

LE N

O.

SA

MP

LE T

YP

E

710.0

705.0

700.0

695.0

690.0

685.0

ELEVATION: 715.0

BORING DEPTH: 30.0


ELE

VA

TIO

N

(fee

t)

GR

AP

HIC

LOG

N V

ALU

E

5

10

15

20

25

30

DE

PT

H

(fee

t)

DRILL RIG: D-50

Dry on 1/28/10






DRILLER: Lynn

30

Page 1 of 2NOTES:

1.

2.

3.

4.





BO

RIN

G L

OG

10-

004

HE

FN

ER

VA

.GP

J S

&M

E.G

DT

2/1

1/10




(blows/ft)

60WA

TE

R L

EV

EL

10



PROJECT:

20

WATER LEVEL:

80

BORING LOG B-09

SA

MP

LE N

O.

SA

MP

LE T

YP

E

ELEVATION: 715.0

BORING DEPTH: 30.0


ELE

VA

TIO

N

(fee

t)

GR

AP

HIC

LOG

N V

ALU

E

DE

PT

H

(fee

t)

DRILL RIG: D-50

Dry on 1/28/10






DRILLER: Lynn

30

Page 2 of 2NOTES:

1.

2.

3.

4.





BO

RIN

G L

OG

10-

004

HE

FN

ER

VA

.GP

J S

&M

E.G

DT

2/1

1/10

Asphalt (4 inches)


FILL: Medium Dense Gray Silty Fine to MediumSAND (SM)

RESIDUUM: Medium Dense to Dense Gray Tanto Tan Brown Silty Fine to Medium SAND (SM)

PARTIALLY WEATHERED ROCK: WhenSampled, becomes Gray White Silty Fine toMedium SAND

16

31

47

40

29

36

50/5.5"


(blows/ft)

60WA

TE

R L

EV

EL

10



PROJECT:

20

WATER LEVEL:

80

BORING LOG B-10

SA

MP

LE N

O.

SA

MP

LE T

YP

E

708.0

703.0

698.0

693.0

688.0

ELEVATION: 713.0

BORING DEPTH: 25.0


ELE

VA

TIO

N

(fee

t)

GR

AP

HIC

LOG

N V

ALU

E

5

10

15

20

25

DE

PT

H

(fee

t)

DRILL RIG: D-50

Dry on 1/27/10






DRILLER: Lynn

30

Page 1 of 2NOTES:

1.

2.

3.

4.





BO

RIN

G L

OG

10-

004

HE

FN

ER

VA

.GP

J S

&M

E.G

DT

2/1

1/10

>>




(blows/ft)

60WA

TE

R L

EV

EL

10



PROJECT:

20

WATER LEVEL:

80

BORING LOG B-10

SA

MP

LE N

O.

SA

MP

LE T

YP

E

ELEVATION: 713.0

BORING DEPTH: 25.0


ELE

VA

TIO

N

(fee

t)

GR

AP

HIC

LOG

N V

ALU

E

DE

PT

H

(fee

t)

DRILL RIG: D-50

Dry on 1/27/10






DRILLER: Lynn

30

Page 2 of 2NOTES:

1.

2.

3.

4.





BO

RIN

G L

OG

10-

004

HE

FN

ER

VA

.GP

J S

&M

E.G

DT

2/1

1/10


FILL: Loose Gray Silty Fine to Medium SAND(SM)

FILL: Soft to Firm Red Orange Silty CLAY (CL)(wet)



8

4

7


(blows/ft)

60WA

TE

R L

EV

EL

10



PROJECT:

20

WATER LEVEL:

80

BORING LOG B-11

SA

MP

LE N

O.

SA

MP

LE T

YP

E

713.0

ELEVATION: 718.0

BORING DEPTH: 7.5


ELE

VA

TIO

N

(fee

t)

GR

AP

HIC

LOG

N V

ALU

E

5

DE

PT

H

(fee

t)

DRILL RIG: D-50

Dry on 1/26/10






DRILLER: Lynn

30

Page 1 of 1NOTES:

1.

2.

3.

4.





BO

RIN

G L

OG

10-

004

HE

FN

ER

VA

.GP

J S

&M

E.G

DT

2/1

1/10

Grass/Rootmat

FILL: Very Stiff Brown Silty Fine Sandy CLAY(CH)

FILL: Very Stiff Brown and Orange Clayey FineSandy SILT (ML)

FILL: Very Stiff Brown Orange and Red FineSandy Silty CLAY (CL)



18

16

14

16


(blows/ft)

60WA

TE

R L

EV

EL

10



PROJECT:

20

WATER LEVEL:

80

BORING LOG B-12

SA

MP

LE N

O.

SA

MP

LE T

YP

E

709.0

704.0

ELEVATION: 714.0

BORING DEPTH: 10.0


ELE

VA

TIO

N

(fee

t)

GR

AP

HIC

LOG

N V

ALU

E

5

10

DE

PT

H

(fee

t)

DRILL RIG: D-50

Dry on 1/27/10






DRILLER: Lynn

30

Page 1 of 1NOTES:

1.

2.

3.

4.





BO

RIN

G L

OG

10-

004

HE

FN

ER

VA

.GP

J S

&M

E.G

DT

2/1

1/10

SUMMARY OF LABORATORY TEST DATA

Boring No. Sample Depth (ft)

Sample Number

*

USCS Classification

Natural Moisture Content

(%)

% Finer No. 200

Atterberg Limits Proctor Data Specific Gravity

Porosity n

Molding Conditions Hydraulic Conductivity k

(cm/sec)

LL PL PIMax. Dry

Density (pcf)

Opt. Moisture

Content (%)

Dry Density

(pcf)

Moisture Content

(%)

B-2 3.5-5 CH 29.7 78.8 65 21 44

B-4 3.5-5 CH 31.7 75.6 74 28 46

Note: Graphic Presentations of Results of Proctor,Grain Size, and other tests follow this summary

* SS = Split Spoon Sample (ASTM D-1586)UD= Undisturbed Sample (ASTM D-1587)BAG= Bulk Sample Job Name: Hefner VAMC

Job Location: Salisbury, NCJob Number: 1351-10-04 PAGE 1 of 1

Geotechnical Engineering Report Hefner VAMC Expansion...

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