Geotechnical Report 3 of 3.pdf

REPORT OF SUBSURFACE INVESTIGATION AND

GEOTECHNICAL ENGINEERING SERVICES

Renovate/Expand SCI Phase II Veterans Affairs Medical Center

Hampton, Virginia

G E T Project No: WM11-152G November 1, 2011

Prepared for:

RDC/John Poe Architects 524 Fernwood Avenue

Altamonte Springs, Florida 32701 Attn: Mr. Thomas M.Hesse, AIA, LEED AP BD+C

1592 Penniman Road, Suite E, Williamsburg, VA 23185 Phone 757-564-6452 ♦ Fax 757-564-6453 ♦ www.getsolutionsinc.com

November 1, 2011

TO: RDC/John Poe Architects 524 Fernwood Avenue Altamonte Springs, Florida 32701

Attn: Mr. Thomas M. Hesse, AIA, LEED AP BD+C

RE: Report of Subsurface Investigation & Geotechnical Engineering Services Renovate/Expand SCI Phase II Veterans Affairs Medical Center Hampton, Virginia GET Project No: WM11-152G

Dear Mr. Hesse:

In compliance with your instructions, we have completed our Subsurface Investigation and Geotechnical Engineering Services for the referenced project. The results of this Study, together with our recommendations, are presented in this report.

Often, because of design and construction details that occur on a project, questions arise concerning subsurface conditions. G E T Solutions, Inc. would be pleased to continue its role as Geotechnical Engineer during the final design phase and project implementation.

Thank you for the opportunity to work with you on this project. We trust that the information contained herein meets your immediate need, and should you have any questions or if we could be of further assistance, please do not hesitate to contact us.

Respectfully Submitted, G E T Solutions, Inc.

James R. Wheeler Project Geologist

Camille A. Kattan, P.E.

Principal Engineer VA Reg. # 018045

Copies: (1) Client via email (thesse@rdcjohnpoe.com)

1592 Penniman Road, Suite E Williamsburg, Virginia 23185 Phone: (757)-564-6452 Fax: (757)-564-6453 info@getsolutionsinc.com

TABLE OF CONTENTS

EXECUTIVE SUMMARY.............................................................................................. i

1.0 PROJECT INFORMATION

1.1 Project Authorization

1.2 Project Site Location and Description

1.3 Project Construction Description

1.4 Purpose and Scope of Services

2.0 FIELD AND LABORATORY PROCEDURES

2.1 Field Exploration

2.2 Laboratory Testing

3.0 SUBSURFACE CONDITIONS

3.1 Site Geology

3.2 Subsurface Soil Conditions

3.3 Groundwater Information

4.0 EVALUATION AND RECOMMENDATIONS

4.1 Clearing and Grading

4.2 Subgrade Preparation (Pavement Areas)

4.3 Structural Fill and Placement

4.4 Suitability of On-Site Soils

4.5 Auger Cast Pile Foundation Recommendations

4.5.1 Axial Compression Capacity Recommendations

4.5.2 Pile Settlement

4.5.3 Test Piles

4.5.4 Pile Installation Monitoring

4.6 Seismic Evaluation

4.7 Pavement Design

5.0 CONSTRUCTION CONSIDERATIONS

5.1 Drainage and Groundwater Concerns

5.2 Site Utility Installation

5.3 Excavations

6.0 REPORT LIMITATIONS

APPENDIX I - BORING LOCATION PLAN

APPENDIX II - CLASSIFICATION SYSTEM FOR SOIL EXPLORATION

APPENDIX III - BORING LOGS

APPENDIX IV - GENERALIZED SOIL PROFILE

APPENDIX V - L-PILE ANALYSIS

APPENDIX VI - SUMMARY OF CBR TEST RESULTS

Report of Subsurface Investigation & Geotechnical Engineering Services November 1, 2011 Renovate/Expand SCI Phase II Veterans Affairs Medical Center Hampton, Virginia GET Project No: WM11-152G i

EXECUTIVE SUMMARY

The project sites are located along Franklin Boulevard towards the southeast corner of the Veterans Affairs Medical Center complex in the City of Hampton, Virginia. The construction is planned to consist of constructing two (2) 1-story additions to the existing SCI building. The building additions are expected to consist of masonry walls, brick veneer, and structural steel framing, supported by a deep foundation system. Also, a asphalt paved or possibly pervious paver type parking lot, a SWM facility, along with other infrastructure components are planned for this development.

Our field exploration program included four (4) 25 to 60-foot deep Standard Penetration Test (SPT) borings drilled within the proposed building addition footprints and one (1) 4.5-foot deep hand auger boring performed within the proposed pavement area. A brief description of the subsurface soil conditions is tabulated below:

Note (1) SPT = Standard Penetration Test, N-Values in Blows-per-foot Note (2) WOH = Weight of Hammer

DEPTH (Feet) STRATUM DESCRIPTION

RANGES OF

SPT(1) N-

VALUES

to

0.17-0.5 Topsoil 2 to 6 inches of Topsoil -

0.17-0.5 to

3.5-8.0

FILL/Possible

FILL

Silty and Clayey SAND (SM and SC) and Sandy, Lean CLAY (CL), both containing varying amounts of Gravel, organics, marine shell fragments, and/or construction debris

Sands:

6 - 24

Clay:

9 - 15

3.5-8.0 to

4.5-29.0 I

SAND (SP, SP-SM, SM, and SC) with varying amounts of Silt and Clay

Isolated deposit of Lean CLAY (CL) was encountered at a depth of 8 to 12 feet and 18 to 22 feet below existing grades at boring locations B-1 and B-4, respectively.

Boring cave-in was encountered in hand auger boring HA-1 at 4.5 feet below existing grades.

2 - 13

22.0-32.0 to

25.0-43.5

II

Lean and Fat CLAY (CL and CH) with varying amounts of Sand

Boring B-2 was terminated within this cohesive layer.

WOH(2) - 9

30.0-43.5 to

60.0 Boring Termination

Depth

III Silty fine to medium SAND (SM) with trace marine shell fragments, “Yorktown Formation” 2 - 65

Veterans Affairs Medical Center Hampton, Virginia GET Project No: WM11-152G ii

The groundwater level was recorded at the boring locations and as observed through the wetness of the recovered soil samples during the drilling operations. The initial groundwater table was estimated to occur at depths of approximately 3.5 to 12 feet below current grades at the boring locations (corresponding to elevations 0 to 1 foot MSL). All boreholes were backfilled upon completion for safety reasons. As such, a stabilized 24-hour reading was not obtained in the borings.

The following evaluations and recommendations were developed based on our field exploration and laboratory-testing program:

The proposed building construction areas should be cleared by means of removing all topsoil, root mat, trees, shrubs, sidewalks, or any otherwise unsuitable materials. It is estimated that an initial cut of up to 6 inches in depth will be required to remove the topsoil materials. This cut is expected to extend deeper in isolated areas to remove deeper deposits of unsuitable soils, organics, and/or unsuitable FILL which becomes evident during the clearing.

A field testing program is recommended during construction. This testing program should include as a minimum, test pits and subgrade load testing (proofrolling) in the pavement areas, compaction testing, pile load testing, and pile installation monitoring, Several 4-foot deep test pits should be excavated within the proposed pavement areas to determine whether the FILL materials may remain in place beneath the pavements or whether it should be removed.

The project’s budget should include an allowance for subgrade improvements (undercut of unsuitable soils and subsequent backfilling).

Considering the proximity of the proposed building additions to the existing building, driven piles could potentially generate vibrations which are potentially damaging to this existing building. As such, an alternative deep foundation, using auger cast piles, has been recommended in order to minimize the vibration levels and minimize the potential for vibration induced damage.

Deep foundations comprised of 14-inch diameter, auger cast piles were evaluated for support of the proposed SCI additions. The pile characteristics are tabulated below:

Lateral Dimensions

Pile Tip Elevation (ft, MSL)1

Allowable Compression

Capacity (tons)

Allowable Tension Capacity

(tons)

Lateral Capacity (tons)2

14-inch Diameter -40 40 20 4

Note (1) Pile tip elevation provided is below mean sea level (MSL).

Note (2) Lateral capacity computed for a lateral load applied at the pile butt level, at ground level for a maximum butt deflection of 0.5 inches for a free end condition or 0.25 inches for a fixed end condition.

Veterans Affairs Medical Center Hampton, Virginia GET Project No: WM11-152G iii

Based on the subsurface profile as indicated by the borings at this site and seismic site testing performed by us in the project vicinity, the site is expected to be a Site Class ‘D’ in accordance with Table 1613.5.2 of the 2009 International Building Code.

Pavement sections to be designed using a CBR value of 12.2; typical pavement sections are provided in the body of the report.

This summary briefly discusses some of the major topics mentioned in the attached report. Accordingly, this report should be read in its entirety to thoroughly evaluate the contents.

Veterans Affairs Medical Center Hampton, Virginia GET Project No: WM11-152G

1.0 PROJECT INFORMATION

1.1 Project Authorization

G E T Solutions, Inc. has completed our Subsurface Investigation and Geotechnical Engineering Services for the proposed Renovate/Expand SCI Phase II project located within the Veterans Affairs Medical Center complex in the City of Hampton, Virginia. The geotechnical engineering services were conducted in general accordance with the scope presented in G E T Proposal No. PVB11-349G, dated September 9, 2011. Verbal authorization to proceed with our services was received initially from the client and then followed up by electronic mail on November 1, 2011.

1.2 Project Site Location and Description

The project sites are located along Franklin Boulevard towards the southeast corner of the Veterans Affairs Medical Center complex in the City of Hampton, Virginia. The project will consist of two additions and a parking lot. The larger of the two additions will be located along the east side of the SCI building, whereas the smaller addition will be located along the west side of the SCI building. The parking lot will be located on the other side of Franklin Boulevard off to the southeast of the existing SCI building.

At the time of our field reconnaissance, the proposed eastern addition footprint is within a landscaped area that is mainly grass covered with several sidewalks, trees, and shrubs.

The western addition is also located in a landscaped area mainly grass covered with sidewalks. The southern portion of this eastern addition footprint is currently within a disturbed area that is fenced off due to construction being completed for the Phase I addition to the SCI building. Elevations within the addition footprints generally range from about 10 to 12 feet MSL and slope slightly downward away from the existing building. The parking lot is in a cleared grass covered area with elevations currently about 3 to 5 feet

MSL.

Photographic documentation of the site conditions at the time of our site reconnaissance is illustrated on the following page in Figures 1 and 2.

Veterans Affairs Medical Center Hampton, Virginia GET Project No: WM11-152G

Figure 1: Facing west looking towards proposed eastern addition location.

Figure 2: Facing east looking towards proposed western addition location.

Veterans Affairs Medical Center Hampton, Virginia GET Project No: WM11-152G

1.3 Project Construction Description

The construction is planned to consist of building two (2) 1-story additions to the existing SCI building. The building additions are planned to be of masonry wall, brick veneer, structural steel framing with an elevated slab. The maximum column and wall loads associated with these structures are not expected to exceed 175 kips and 5 klf, respectively. Finished floor elevations are expected to coincide with the existing building floor elevations and be supported over a crawl space. Finish grades for the crawl space are not known at this time, but are expected to be several feet or more below current grades similar to the Phase I addition. Therefore, cuts up to 5 feet, possibly more, are expected to be required in order to establish finish grades for the crawl spaces.

The specific design of the parking lot is not known at this time, but is expected to consist of either an asphalt or pervious paver type parking lot. From our understanding, several feet of fill (about 3 to 5 feet) will be required to establish finish grades within parking lot area.

Also, other infrastructure components (utilities, SWM facility, etc.) are planned for this development.

If any of the noted information is incorrect or has changed, please inform G E T Solutions, Inc. so that we may amend the recommendations presented in this report, if appropriate.

1.4 Purpose and Scope of Services

The purpose of this study was to obtain information on the general subsurface conditions at the proposed project site. The subsurface conditions encountered were then evaluated with respect to the available project characteristics. In this regard, engineering assessments for the following items were formulated:

1. General assessment of the soils revealed by the borings performed at the proposed development.

2. General location and description of potentially deleterious material encountered in the borings that may interfere with construction progress or structure performance, including existing fills or surficial/subsurface organics.

3. Soil subgrade preparation, including stripping, grading and compaction.

Engineering criteria for placement and compaction of approved structural fill material.

4. Construction considerations for fill placement and subgrade preparation.

5. Feasibility of utilizing a deep foundation system for support of the proposed additions. Design parameters required for the foundation system, including pile type, pile length, allowable capacities, and expected total and differential settlements. Also, pile installation and testing criteria is evaluated and discussed in this report.

Veterans Affairs Medical Center Hampton, Virginia GET Project No: WM11-152G

6. Evaluation of the subsurface profile to determine the site class definition for earthquake design considerations based on the 2009 International Building Code (IBC).

7. Typical pavement sections based on the field exploration and our experience with similar soil conditions.

The scope of services did not include an environmental assessment for determining the presence or absence of wetlands or hazardous or toxic material in the soil, bedrock, surface water, groundwater or air, on or below or around this site.

2.0 FIELD AND LABORATORY PROCEDURES

2.1 Field Exploration

In order to explore the general subsurface soil types and to aid in developing associated foundation design parameters, four (4) 25 to 60-foot deep Standard Penetration Test (SPT) borings (designated as B-1 through B-4) were drilled by G E T Solutions, Inc. within the proposed building addition footprints.

The SPT borings were performed with the use of rotary wash “mud” drilling procedures in general accordance with ASTM D 1586. The tests were performed continuously from the existing ground surface to a depth of 12 feet, and at 5-foot intervals thereafter. The soil samples were obtained with a standard 1.4” I.D., 2” O.D., 30” long split-spoon sampler. The sampler was driven with blows of a 140 lb. hammer falling 30 inches, using an automatic hammer. The number of blows required to drive the sampler each 6-inch increment of penetration was recorded and is shown on the boring logs. The sum of the second and third penetration increments is termed the SPT N-value (uncorrected for automatic hammer). A representative portion of each disturbed split-spoon sample was collected with each SPT, placed in a glass jar, sealed, labeled, and returned to our laboratory for review.

In order to explore the general subsurface soil types and to aid in developing associated pavement design parameters, one (1) 4.5-foot deep hand auger boring (designated as HA-

1) was performed within the proposed pavement area. In addition, one (1) bulk soil sample (designated as CBR-1) was collected from the proposed pavement area at this hand auger boring location. The bulk subgrade soil sample was collected from a depth ranging from 0.5 to 1.5 feet below existing grades. The bulk soil sample was returned to our laboratory and subjected to CBR, Proctor, and classification testing in accordance with ASTM standards

The boring and CBR locations were established and located in the field by a representative of G E T Solutions, Inc. The approximate boring locations are shown on the “Boring Location Plan” included in Appendix I.

Veterans Affairs Medical Center Hampton, Virginia GET Project No: WM11-152G

2.2 Laboratory Testing

Representative portions of all soil samples collected during drilling were sealed in glass jars or plastic bags, labeled and transferred to our laboratory for classification and analysis.

The soil classification was performed by a Geotechnical Engineer in accordance with ASTM D 2488. The classification system for soil exploration is included in Appendix II.

Four (4) representative soil split spoon samples were selected and subjected to natural moisture, -#200 sieve wash, and Atterberg Limits testing and analysis in order to corroborate the visual classification of the soils. These test results are tabulated below and are also presented on the “Boring Logs” sheets of Appendix III.

Table I - Laboratory Classification Test Results

Boring No.

Depth (Ft)

Natural Moisture

Content (%)

-#200 Sieve

Atterberg Limits

LL/PL/PI

USCS

Classification

B-1 38-40 47 99 46/19/27 CL

B-3 23-25 54 71 66/29/37 CH

B-3 43-45 34 17 Non Plastic SM B-4 53-55 28 26 Non Plastic SM

The bulk soil sample that was obtained from the proposed pavement area was returned to the laboratory and subjected to natural moisture content, -#200 sieve wash, Atterberg Limits, Standard Proctor, and CBR testing in accordance with ASTM standards. These test results are presented on the Summary of CBR Test Results in Appendix VII.

3.0 SUBSURFACE CONDITIONS

3.1 Site Geology

The project site lies within a major physiographic province called the Atlantic Coastal Plain.

Numerous transgressions and regressions of the Atlantic Ocean have deposited marine, lagoonal, and fluvial (stream lain) sediments. The regional geology is very complex, and generally consists of interbedded layers of varying mixtures of sands, silts and clays.

Based on our review of existing geologic and soil boring data, the geologic stratigraphy encountered in our subsurface explorations generally consisted of marine deposited sands, silts and clays, and late Pliocene age deposits of the Yorktown Formation. The Yorktown Formation stratum, once encountered, generally extends to depths of several hundred feet below sea level.

Veterans Affairs Medical Center Hampton, Virginia GET Project No: WM11-152G

3.2 Subsurface Soil Conditions

The results of our field exploration program indicated the following:

Table II – Subsurface Soil Conditions

DEPTH (Feet) STRATUM DESCRIPTION

RANGES OF

SPT(1) N-

VALUES

to

0.17-0.5 Topsoil 2 to 6 inches of Topsoil -

0.17-0.5 to

3.5-8.0

FILL/Possible

FILL

Silty and Clayey SAND (SM and SC) and Sandy, Lean CLAY (CL), both containing varying amounts of Gravel, organics, marine shell fragments, and/or construction debris

Sands:

6 - 24

Clay:

9 - 15

3.5-8.0 to

4.5-29.0 I

SAND (SP, SP-SM, SM, and SC) with varying amounts of Silt and Clay

Isolated deposit of Lean CLAY (CL) was encountered at a depth of 8 to 12 feet and 18 to 22 feet below existing grades at boring locations B-1 and B-4, respectively.

Boring cave-in was encountered in hand auger boring HA-1 at 4.5 feet below existing grades.

2 - 13

22.0-32.0 to

25.0-43.5

II

Lean and Fat CLAY (CL and CH) with varying amounts of Sand

Boring B-2 was terminated within this cohesive layer.

WOH(2) - 9

30.0-43.5 to

60.0 Boring Termination

Depth

III Silty fine to medium SAND (SM) with trace marine shell fragments, “Yorktown Formation” 2 - 65

Note (1) SPT = Standard Penetration Test, N-Values in Blows-per-foot Note (2) WOH = Weight of Hammer

It is noted that the topsoil designation references the presence of surfical organic laden soil, and does not represent any particular quality specification. This material is to be tested for approval prior to use.

The subsurface description is of a generalized nature provided to highlight the major soil strata encountered. The records of the subsurface exploration included in Appendix III (Boring Logs sheets) and in Appendix IV (Generalized Soil Profile) should be reviewed for specific information as to the individual borings. The stratifications shown on the records of the subsurface exploration represent the conditions only at the actual boring locations.

Variations may occur and should be expected between boring locations. The stratifications represent the approximate boundary between subsurface materials and the transition may be gradual.

Veterans Affairs Medical Center Hampton, Virginia GET Project No: WM11-152G

3.3 Groundwater Information

The groundwater level was recorded at the boring locations and as observed through the wetness of the recovered soil samples during the drilling operations. The initial groundwater table was estimated to occur at depths of approximately 3.5 to 12 feet below current grades at the boring locations (corresponding to elevations 0 to 1 foot MSL). All boreholes were backfilled upon completion for safety reasons. As such, a stabilized groundwater reading was not obtained at the boring locations.

As subsurface soils begin to dry moisture moves upwards through the soil profile by means of capillary action. Based on the subsurface soil composition (soils containing more than 30% of fines by weight), these initial groundwater readings (based on the relative wetness of the soils) could be in part attributed to the capillary action of the soils. As such, if the static groundwater elevation is critical to the design of the proposed structure and site infrastructure it is recommended to install temporary groundwater monitoring wells to substantiate these initial readings.

Groundwater conditions will vary with environmental variations and seasonal conditions such as the frequency and magnitude of rainfall patterns and tides, as well as, man-made influences, such as existing swales, drainage ponds, under-drains and areas of covered soil (paved parking lots, side walks, etc.). In the project’s area, seasonal groundwater fluctuations of 3 feet are common; however, greater fluctuations have been documented.

Again, we recommend that the contractor determine the actual groundwater levels at the time of the construction to determine groundwater impact on the construction procedures, if necessary.

4.0 EVALUATION AND RECOMMENDATIONS

Our recommendations are based on the previously discussed project information, our interpretation of the SPT borings, laboratory data, and our observations during our site reconnaissance. If the proposed construction should vary from what has been described herein, or should differing conditions be encountered during construction, we request the opportunity to review our recommendations and make any necessary changes.

On the basis of the results of our soil test borings and in conjunction with the anticipated high foundation loads associated with the building additions, it is our opinion that the proposed framing should be supported by means of a deep foundation system.

Due to the large amount of energy required to install driven deep foundations, vibrations of considerable magnitudes are generated. These vibrations could be potentially damaging the existing SCI building. As such, an alternative deep foundation consisting of auger cast piles will minimize the vibrations and reduce the risk for potential vibration related damage/ disturbances in the adjacent building.

Veterans Affairs Medical Center Hampton, Virginia GET Project No: WM11-152G

Section 4.5 describes the pile capacity analysis and provides our recommendations for axial compressive, tensile, and lateral pile capacities; the pile testing program; and pile construction criteria for auger cast piles. In addition, we have provided estimates of potential settlement.

4.1 Clearing and Grading

The proposed construction areas should be cleared by means of removing all topsoil, root mat, trees, shrubs, sidewalks, or any otherwise unsuitable materials. It is estimated that a cut of up to 6 inches in depth will be required to remove the topsoil materials. This cut is expected to extend deeper in isolated areas to remove deeper deposits of unsuitable soils, and/or organics which become evident during the clearing.

The results of our field exploration program indicated that the soils below the topsoil material predominantly consisted of Silty and Clayey SAND (SM and SC) and Sandy, Lean CLAY (CL). Combinations of excess surface moisture from precipitation ponding on the site and the construction traffic, including heavy compaction equipment, may create pumping and general deterioration of the bearing capabilities of the surface soils. Therefore, undercutting to remove very soft soils in isolated areas should be anticipated. In this regard, and in order to reduce the potential for undercutting, care should be exercised during the grading and construction operations at the site. Furthermore, inherently wet subgrade soils combined with potential poor site drainage make this site particularly susceptible to subgrade deterioration. Thus, grading should be performed during a dry season if at all possible. This should minimize these potential problems, although they may not be eliminated.

It is recommended that the budget include an allowance for undercutting of unsuitable soils and replacing them with Imported Structural Fill and/or additional Aggregate Base Material within the pavement areas.

Control of surface water is very important to the successful completion of the proposed construction. The contractor should plan his grading activities to control surface water and minimize erosion of exposed cut or fill material. This may include constructing temporary berms, ditches, and swales to intercept runoff and discharge it in a controlled fashion.

4.2 Subgrade Preparation (Pavement Areas)

Following the clearing operation, the exposed subgrade soils should be densified with a large static drum or sheepsfoot roller. Subgrades to a depth of at least 6 inches should be compacted to a dry density of at least 95% of the Standard Proctor maximum dry density, in accordance with ASTM D 698 (if possible). The moisture content of the subgrade should be within +/- 2% of the optimum moisture content at the time of compaction. These compaction and moisture recommendations may be achievable in the relatively wet environment. As such, some subgrade improvements should be expected.

Veterans Affairs Medical Center Hampton, Virginia GET Project No: WM11-152G

After the subgrade soils have been compacted, they should be evaluated by G E T Solutions, Inc. for stability. Accordingly, the subgrade soils should be proofrolled to check for pockets of loose material hidden beneath a crust of better soil. Several passes should be made by a large rubber-tired roller or loaded dump truck over the construction areas, with the successive passes aligned perpendicularly (if possible). The number of passes will be determined in the field by the Geotechnical Engineer depending on the soil conditions. Any pumping and unstable areas observed during proofrolling (beyond the initial cut) should be undercut and/or stabilized at the direction of the Geotechnical Engineer. These improvement recommendations (where required) should also consider the thickness of the subbase and its ability to bridge marginal areas.

In addition to the proofroll, several 4-foot deep test pits should be excavated within the proposed pavement areas. The test pits are considered necessary to determine the thickness and composition of the FILL materials. The test pits should be performed under the observation of a representative G E T Solutions, Inc., who will evaluate the composition of the recovered soils. In addition to the test pits, several compaction tests should be performed on the FILL material within the proposed pavement areas to further substantiate the suitability of the existing material. It is possible that some subgrade improvements will be required to provide suitable soils for pavement support. The FILL material may remain in place under pavements if approved by the Geotechnical Engineer (to be determined following the completion of the test pits and compaction testing).

Recommendations concerning the subgrade improvements (as necessary) will be provided in the field following the testing procedures. Again, the project’s budget should include an allowance for subgrade improvements within the pavement areas (undercut/backfill with Structural Fill or Aggregate Base Material).

4.3 Structural Fill and Placement

Any material to be used for Structural Fill should be evaluated and tested by G E T Solutions, Inc. prior to placement to determine if they are suitable for the intended use.

Suitable Structural Fill material should consist of sand or gravel containing less than 25% by weight of fines (SP, SM, SW, GP, GW - with dimensions not to exceed 2 inches in diameter), having a liquid limit less than 20 and plastic limit less than 6, and should be free of rubble, organics, clay, debris and other unsuitable material.

All Structural Fill should be compacted to a dry density of at least 95% of the Standard Proctor maximum dry density, in accordance with ASTM D698. The moisture content of the Structural Fill should be within +/- 2% of the optimum moisture content at the time of placement. In general, the compaction should be accomplished by placing the fill in maximum 8-inch loose lifts and mechanically compacting each lift to at least the specified minimum dry density.

We recommend that fill placement be monitored on a full-time basis by a qualified Geotechnical Engineering firm to verify that the specified materials are used and the required degree of compaction is achieved.

Veterans Affairs Medical Center Hampton, Virginia GET Project No: WM11-152G

Surface water control measures should be instituted to protect the new fill from erosion. A protective cover of grass or other vegetation should be established on permanent slopes as soon as possible during construction.

Utility excavations may encounter the groundwater table, depending on utility depth and location on site. Dewatering at depths below the groundwater level may require well pointing. Seepage from shallow perched water may require pumping from sumps, depending on seasonal conditions. Prior to bidding and/or construction, the grading contractor should determine actual groundwater conditions at the location of deep excavations so its impact on the project can be determined.

4.4 Suitability of On-Site Soils

Based on our laboratory and visual classification, the majority of the subsurface soils do not appear suitable for reuse as Structural Fill. Some of the SAND (SP-SM, SM) subgrade soils recovered beneath the FILL materials may be suitable for reuse as Structural Fill;

however, these soils are commonly located near or below the groundwater level and will require extensive moisture manipulation (stockpiling and placement in thin lifts) prior to their use. In order to verify the acceptance or rejection of the existing soils for re-use as Structural Fill, additional classification tests (natural moisture and -#200 sieve wash) will have to be performed during construction.

4.5 Auger Cast Pile Foundation Recommendations

4.5.1 Axial Compression Capacity Recommendations

For this project, we have analyzed 14-inch diameter auger cast piles. Auger cast piles consist of drilling to a desired depth with a continuous flight auger. Then, as the auger is slowly withdrawn, concrete grout is injected through the auger’s stem.

The workmanship is critical for the auger cast piling system to be successful. As such, it is recommended to retain the services of G E T Solutions, Inc. to perform construction inspection services during the project implementation. The duties of the inspector will be described in more detail in the following sections.

We conducted pile capacity analyses using static formulas with coefficients recommended by Geoffrey Myerhoff and George Sowers. The analyses include the contributions of shaft friction and end bearing to the pile capacity. The piles are expected to derive their capacity from the combination of end bearing and friction resistance associated with the medium dense Sands of the subsurface profile.

Veterans Affairs Medical Center Hampton, Virginia GET Project No: WM11-152G

Table III below provides our recommended pile diameter and embedment depth for the foundations. The allowable capacity for the piles includes a safety factor of at least 2.0 to allow for a pile load test program. The capacity of a group of piles spaced at least 3 pile diameters apart, center to center, can be taken as the sum of the individual capacities with no reduction factor. If closer pile spacing is anticipated, the Geotechnical Engineer should be contacted to evaluate the efficiency of the specific pile group. The final tip elevations will be adjusted based on the results of the load test program(s).

Table III – Pile Length and Capacity for 14 inch Auger Cast Piles

Lateral Dimensions

Pile Tip Elevation (ft, MSL)1

Allowable Compression

Capacity (tons)

Allowable Tension Capacity

(tons)

Lateral Capacity (tons)2

14-inch Diameter -40 40 20 4

Note (1) Pile tip elevation provided is below mean sea level (MSL).

Note (2) Lateral capacity computed for a lateral load applied at the pile butt level, at ground level for a maximum butt deflection of 0.5 inches for a free end condition or 0.25 inches for a fixed end condition.

We conducted our lateral analyses using L-Pile Plus, a computer software package by ENSOFT. The software requires as input, quantitative data related to strength and deformation behavior of the subsurface materials, the structural properties of the pile, and an understanding of shaft/soil interaction during lateral loading. The program calculates the lateral deflections, internal moment forces and internal shear forces experienced by a pile subjected to the specific loading conditions. The program does not analyze whether the pile is structurally capable of resisting the moments and shear stresses generated.

This analysis should be performed by the project structural engineer. The L-Pile data sheets are attached to this report (Appendix V).

If for some reason during construction, auger “refusal” is encountered before the piles reach their design tip elevations, the Geotechnical Engineer should be retained to provide specific recommendations for this condition. The reinforcing steel (cage) should be designed by the project Structural Engineer, who should also evaluate the structural capacity of the pile as related to the above provided pile/soil capacities.

4.5.2 Pile Settlement

Based on the results of load tests performed on piles in similar soil conditions, it is anticipated that the total butt settlements (including elastic shortening) will not exceed about ½-inch, which is the settlement necessary to mobilize the soil/pile capacity in combination with the pile tip settlements due to the stress increase in the underlying soils.

Veterans Affairs Medical Center Hampton, Virginia GET Project No: WM11-152G

4.5.3 Test Piles

We recommend the installation of at least three (3) test piles for the eastern addition and two (2) test piles for the western addition and performing a static pile load test on at least two (2) of the test piles (one per addition) to confirm the design pile depth and capacity.

The Geotechnical Engineer should be called on to recommend test pile locations once the foundation plan is complete and pile locations have been determined. The load test should be performed in accordance with Procedure A (Quick Test) of ASTM D 1143 – Standard Test Methods for Deep Foundations Under Static Axial Compressive Load and carried out to at least 2.0 times the design load, or failure. The pile load test should be performed under the observation of the Geotechnical Engineer or his representative who should record the dial gage readings. The records of the pile load test should be reviewed by the Geotechnical Engineer and the Structural Engineer to verify the pile design criteria. The production piles should be installed using the same equipment and methods as for the test piles.

4.5.4 Pile Installation Monitoring

The Geotechnical Engineer should observe the installation of the test piles and all production piles. The purpose of the geotechnical engineer’s observations is to determine if production installations are being performed in accordance with the previously derived criteria. Continuous installation records should be maintained for all piles. The field duties of the Geotechnical Engineer (or a qualified engineer’s representative) should include the following:

1. Being knowledgeable of the subsurface conditions at the site and the project-specific criteria.

2. Being aware of aspects of the installation including type of pile equipment and pile installation tolerances.

3. Keeping an accurate record of pile installation and procedures.

4. Documenting that the piles are installed to the proper depth indicative of the intended bearing stratum.

5. Perform flow cone testing to insure specification requirements are met.

6. Generally confirming that the pile installation equipment is operating as anticipated.

7. Mold grout compressive strength test specimens.

8. Informing the geotechnical engineer of any unusual subsurface conditions.

9. Notifying the contractor and structural engineer when unanticipated difficulties or conditions are encountered.

Veterans Affairs Medical Center Hampton, Virginia GET Project No: WM11-152G

10. Document quantity of grout pumped into each pile hole.

11. Provide rated load capacity of the pile.

4.6 Seismic Evaluation

Based on the subsurface profile as indicated by the borings at this site and seismic site testing performed by us in the project vicinity, the site is expected to be a Site Class ‘D’ in accordance with Table 1613.5.2 of the 2009 International Building Code.

4.7 Pavement Design

Our design assumes that either curbs and gutters or ditches and swales will be provided along the edges of all pavements to prevent water penetration of the subgrade soils.

Based on the results of our soil borings, it appears that the soils that will be exposed as pavement subgrade will consist mainly of Silty SAND (SM). In accordance with VDOT standards, the average soaked CBR value was multiplied by a factor of two-thirds to determine a pavement design CBR value. The two-thirds factor provides the necessary safety margins to compensate for some non-uniformity of the soil. Therefore, a design CBR value of 12.2 should be used to evaluate the pavement sections at this project site. Typical pavement sections are provided in Table IV below.

Table IV – Typical Pavement Sections

Hot Mix Asphalt Section

Reinforced Portland Cement Concrete (min.

4,000 psi) Surface Base

Aggregate Base1 Subgrade2

Light Duty Parking Stalls - 2” - 8” Stable and Compacted

Heavy Duty Parking Lot Drive

Isle/Entrances

- 2” 3” 8” Stable and Compacted

Heavy Duty Dumpster Pad 6” - - 8” Stable and Compacted

1 - VDOT Type 21-A, compacted to a dry density of at least 95% of the Standard Proctor maximum dry density (ASTM D 698).

2 - Compacted to a dry density of at least 95% of the Standard Proctor maximum dry density (ASTM D 698).

As previously stated, the subgrade soils consisted primarily of Silty SAND (SM), which has high fines content (Silt) and is moisture sensitive. Accordingly, during the subgrade testing (proofrolling and compaction testing) isolated areas of unstable subgrade soils will probably become evident. Subgrade scarification, aeration, and drying or subgrade stabilization in the form of undercutting may be required to achieve a stable subgrade.

Veterans Affairs Medical Center Hampton, Virginia GET Project No: WM11-152G

Actual pavement section thickness should be provided by the design Civil Engineer based on traffic loads, volume, and the owners design life requirements. The above section corresponds to thickness representative of typical local construction practices and periodic maintenance should be anticipated. All pavement material and construction procedures should conform to Virginia Department of Transportation (VDOT) requirements.

Following pavement rough grading operations, the exposed subgrade should be observed under proofrolling. This proofrolling should be accomplished with a fully loaded dump truck or 7 to 10 ton drum roller to check for pockets of soft material hidden beneath a thin crust of better soil. Any unsuitable materials thus exposed should be removed and replaced with a well-compacted material. The inspection of these phases should be performed by the Geotechnical Engineer or his representative. The subgrade soils are likely to be unstable at the time of construction and some ground improvement requirements are anticipated.

Considering this, the project’s budget should include a contingency to accommodate the potential subgrade improvements.

Where excessively unstable subgrade soils are observed during proofrolling and/or fill placement, it is expected that these weak areas can be stabilized by means of thickening the aggregate base course layer by 4 to 6 inches and/or lining the subgrade with geotextile fabric. These recommendations are to be addressed by the Geotechnical Engineer during construction, if necessary, who will recommend the most economical approach at the time.

5.0 CONSTRUCTION CONSIDERATIONS

5.1 Drainage and Groundwater Concerns

It is expected that dewatering may be required for excavations that extend near or below the groundwater table. Dewatering above the groundwater level could probably be accomplished by pumping from sumps. Dewatering at depths below the groundwater level will require well pointing.

It would be advantageous to construct all fills early in the construction. If this is not accomplished, disturbance of the existing site drainage could result in collection of surface water in some areas, thus rendering these areas wet and very loose. Temporary drainage ditches should be employed by the contractor to accentuate drainage during construction.

We recommend that the contractor determine the actual groundwater levels at the time of construction to determine groundwater impact on this project.

Veterans Affairs Medical Center Hampton, Virginia GET Project No: WM11-152G

5.2 Site Utility Installation

Based on our laboratory and visual classification, the majority of the subsurface soils do not appear suitable for reuse as Structural Fill. Some of the SAND (SP-SM, SM) subgrade soils recovered beneath the FILL materials may be suitable for reuse as Structural Fill;

however, these soils are commonly located near or below the groundwater level and will require extensive moisture manipulation (stockpiling and placement in thin lifts) prior to their use. In order to verify the acceptance or rejection of the existing soils for re-use as Structural Fill, additional classification tests (natural moisture and -#200 sieve wash) will have to be performed during construction.

It is possible that isolated utility pipes and structures will bear within the wet granular materials located at depths in excess of 3 feet below current grades within the pavement areas and about 10 feet below current grades within the building addition areas. In these instances additional bedding materials (VDOT No. 57 stone) may be required to facilitate suitable pipe and/or structure bedding.

5.3 Excavations

In Federal Register, Volume 54, No. 209 (October, 1989), the United States Department of Labor, Occupational Safety and Health Administration (OSHA) amended its “Construction Standards for Excavations, 29 CFR, part 1926, Subpart P”. This document was issued to better insure the safety of workmen entering trenches or excavations. It is mandated by this federal regulation that all excavations, whether they be utility trenches, basement excavation or footing excavations, be constructed in accordance with the new (OSHA) guidelines. It is our understanding that these regulations are being strictly enforced and if they are not closely followed, the owner and the contractor could be liable for substantial penalties.

The contractor is solely responsible for designing and constructing stable, temporary excavations and should shore, slope, or bench the sides of the excavations as required to maintain stability of both the excavation sides and bottom. The contractor’s responsible person, as defined in 29 CFR Part 1926, should evaluate the soil exposed in the excavations as part of the contractor’s safety procedures. In no case should slope height, slope inclination, or excavation depth, including utility trench excavation depth, exceed those specified in local, state, and federal safety regulations.

We are providing this information solely as a service to our client. G E T Solutions, Inc. is not assuming responsibility for construction site safety or the contractor’s activities; such responsibility is not being implied and should not be inferred.

Veterans Affairs Medical Center Hampton, Virginia GET Project No: WM11-152G

6.0 REPORT LIMITATIONS

The recommendations submitted are based on the available soil information obtained by G E T Solutions, Inc. and the information supplied by the client and its consultants for the proposed project. If there are any revisions to the plans for this project or if deviations from the subsurface conditions noted in this report are encountered during construction, G E T Solutions, Inc. should be notified immediately to determine if changes in the foundation recommendations are required. If G E T Solutions, Inc. is not retained to perform these functions, G E T Solutions, Inc. can not be responsible for the impact of those conditions on the geotechnical recommendations for the project.

The Geotechnical Engineer warrants that the findings, recommendations, specifications or professional advice contained herein have been made in accordance with generally accepted professional geotechnical engineering practices in the local area. No other warranties are implied or expressed.

After the plans and specifications are more complete the Geotechnical Engineer should be provided the opportunity to review the final design plans and specifications to assure our engineering recommendations have been properly incorporated into the design documents so that the earthwork and foundation recommendations can be properly interpreted and implemented. At that time, it may be necessary to submit supplementary recommendations. This report has been prepared for the exclusive use of RDH/John Poe Architects and their consultants for the specific application to the Renovate/Expand SCI Phase II project located in the City of Hampton, Virginia.

APPENDICES

I BORING LOCATION PLAN

II CLASSIFICATION SYSTEM FOR SOIL EXPLORATION

III BORING LOGS

IV GENERALIZED SOIL PROFILE

V L-PILE ANALYSIS

VI SUMMARY OF CBR TEST RESULTS

APPENDIX I

BORING LOCATION PLAN

Locations are approximate based on site visit sketch.

NORTH

Boring Location Plan

Project: Renovate/Expand SCI Phase II Veteran Affairs Medical Center, Hampton, Virginia Scale: As Drawn

Project No: WM11-152G Date: 11/1/2011 Client: John Poe Architects Plot By: RT

B-4

B-1

B-3

CBR1/HA-1

B-2

APPENDIX II

CLASSIFICATION SYSTEM FOR SOIL EXPLORATION

Very Loose 4 blows/ft. or less Very Soft 2 blows/ft. or less Loose 5 to 10 blows/ft. Soft 3 to 4 blows/ft.

Medium Dense 11 to 30 blows/ft. Medium Stiff 5 to 8 blows/ft.

Dense 31 to 50 blows/ft. Stiff 9 to 15 blows/ft.

Very Dense 51 blows/ft. or more Very Stiff 16 to 30 blows/ft.

Hard 31 blows/ft. or more

Boulders 8 inch diameter or more Cobbles 3 to 8 inch diameter Gravel Coarse 1 to 3 inch diameter

Medium 1/2 to 1 inch diameter Fine 1/4 to 1/2 inch diameter

Sand Coarse 2.00 mm to 1/4 inch (diameter of pencil lead)

Medium 0.42 to 2.00 mm (diameter of broom straw)

Fine 0.074 to 0.42 mm (diameter of human hair)

Silt 0.002 to 0.074 mm (cannot see particles)

GW - Well-graded Gravel CL - Lean Clay GP - Poorly graded Gravel CL-ML - Silty Clay GW-GM - Well-graded Gravel w/Silt ML - Silt GW-GC - Well-graded Gravel w/Clay OL - Organic Clay/Silt GP-GM - Poorly graded Gravel w/Silt Less than 5 percent GW, GP, SW,SP GP-GC - Poorly graded Gravel w/Clay CH - Fat Clay More than 12 percent GM, GC, SM, SC GM - Silty Gravel MH - Elastic Silt 5 to 12 percent GC - Clayey Gravel OH - Organic Clay/Silt GC-GM - Silty, Clayey Gravel SW - Well-graded Sand SP - Poorly graded Sand PT - Peat SW-SM - Well-graded Sand w/Silt SW-SC - Well-graded Sand w/Clay SP-SM - Poorly graded Sand w/Silt SP-SC - Poorly graded Sand w/Clay SM - Silty Sand SC - Clayey Sand SC-SM - Silty, Clayey Sand

Particle Size Identification

Consistency

GET Revision 12/12/07

Coarse Grained Soils Fine-Grained Soils

Highly Organic Soils

50% or more passes the No. 200 sieve

Liquid Limit 50% or greater

Trace

CLASSIFICATION SYSTEM FOR SOIL EXPLORATION

Standard Penetration Test (SPT), N-value

Relative Density

NON COHESIVE SOILS

(SILT, SAND, GRAVEL and Combinations)

Standard Penetration Tests (SPT) were performed in the field in general accordance with ASTM D 1586. The soil samples were obtained with a standard 1.4” I.D., 2” O.D., 30” long split-spoon sampler. The sampler was driven with blows of a 140 lb. hammer falling 30 inches. The number of blows required to drive the sampler each 6-inch increment (4 increments for each soil sample) of penetration was recorded and is shown on the boring logs. The sum of the second and third penetration increments is termed the SPT N-value.

(252) 335-9765

Williamsburg Office 1592 Penniman Rd. Suite E

Williamsburg, Virginia 23185

0-5 5-10

Virginia Beach Office 204 Grayson Road

Virginia Beach, VA 23462

(757) 518-1703 (757) 564-6452

Elizabeth City Office 504 East Elizabeth St. Suite 2

Elizabeth City, NC 27909

COHESIVE SOILS

(CLAY, SILT and Combinations)

Relative Proportions Descriptive Term Percent

15-25 30-45

Few Little Some

Mostly 50-100

Depending on percentage of fines (fraction smaller than No.

200 sieve size), coarse-grained soils are classified as follows:

Borderline cases requiring dual symbols

P…