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Geotechnical Engineering Report

West Point Elementary School U.S. Military Academy West Point, New York

December 2, 2014

19955 Highland Vista Drive, Suite 170 Ashburn, VA 20147 Phone 703 726 8030 ● www.geoconcepts-eng.com

19955 Highland Vista Dr., Suite 170 Ashburn, Virginia 20147

(703) 726-8030 www.geoconcepts-eng.com

December 2, 2014

Mr. John L. Capelli, AIA EwingCole Federal Reserve Bank Building 100 N, 6th Street Philadelphia, Pennsylvania 19106-1590

Subject: Geotechnical Engineering Report, West Point Elementary School, US Military Academy, West Point, New York (GeoConcepts Project No. 14214)

Dear Mr. Capelli:

GeoConcepts Engineering, Inc. (GeoConcepts) is pleased to present the following geotechnical engineering report prepared for West Point Elementary School in West Point, New York.

We appreciate the opportunity to serve as your geotechnical consultant on this project. Please do not hesitate to contact me if you have any questions or want to meet to discuss the findings and recommendations contained in the report.

Sincerely, GEOCONCEPTS ENGINEERING, INC.

Paul Burkart, PE Principal pburkart@geoconcepts-eng.com mailto:pburkart@geoconcepts-eng.com

Table of Contents

1.0 Scope of Services

2.0 Site Description and Proposed Construction

3.0 Subsurface Conditions

3.1 Geology

3.2 Stratification

3.3 Groundwater

3.4 Soil Laboratory Test Results

3.5 Metal Corrosion/Concrete Attack Test Results

3.6 Seismic Site Classification

3.7 Test Pit Investigation

4.0 Geotechnical Engineering Analysis

4.1 Spread Footings

4.2 Lower Floor Slabs on Grade

4.3 Lateral Earth Pressures and Subdrainage

4.4 Pavements

4.5 Earthwork

4.6 Rock Excavation

4.7 Excavation Support/Underpinning

4.8 Infiltration Analysis

4.8.1 Infiltration Test Results

4.8.2 Classification Test Results

4.8.3 Recommended Design Infiltration Rate

4.9 Landfill Use Comments

5.0 Environmental Analysis

5.1 PID Screening

5.2 Methane Monitoring

5.3 Chemical Laboratory Test Results

5.4 Recommendations

6.0 General Limitations

Figure 1: Site Vicinity Map Figure 2: Design Earth Pressures for Basement Walls Figure 3: Design Earth Pressures for Site Retaining Walls Figure 4: Foundation Subdrainage Design Recommendations Figure 5: Compacted Structural Fill Diagram

Appendix A: Subsurface Investigation Appendix B: Soil Laboratory Test Results

1.0 Scope of Services

This geotechnical engineering report presents the results of the field investigation, soil laboratory testing, and engineering analysis of the geotechnical data. This report specifically addresses the following:

• An evaluation of subsurface conditions within the area of the proposed site development, including metal corrosion and concrete attack potential of on-site soils, and a seismic site classification per the International Building Code.

• Foundation recommendations for support of the proposed building and lower floor slabs on grade.

• Lateral earth pressures and subdrainage for use in design of basement and site retaining walls.

• An assessment of subgrade conditions for support of pavements, including an estimated design

CBR value.

• Earthwork recommendations for construction of loadbearing fills, including an assessment of on-site soils to be excavated for re-use as fill.

• Recommendations regarding rock excavation for the site development.

• Recommendations for excavation support, including underpinning of the existing gymnasium building.

• Recommendations for stormwater management by infiltration.

• Comments regarding potential uses and limitations of the existing landfill area.

• Recommendations regarding the use of a passive or active methane gas venting system for the proposed building, based on the field screening of test boreholes.

Services not specifically identified in the contract for this project are not included in the scope of services.

2.0 Site Description and Proposed Construction

The West Point Elementary School site is located at 705 Barry Road in West Point, New York. A site vicinity map is presented as Figure 1 at the end of this report. The existing elementary school will be replaced with a new elementary school building located to the north of the existing gymnasium. The existing gymnasium has a lower floor level at elevation (EL) 258.7. The site of the new school is currently wooded, and a covered landfill (currently athletic fields) is located immediately to the northeast of the new proposed school building. The site of the existing elementary school will eventually be turned into an at grade parking lot. The ground surface elevation at the location of the new school building ranges from about EL 230 to EL 265, generally sloping downward towards the northeast.

December 2, 2014 14214 Page 1

Imagery provided by Google Earth © 2014

Based on plans provided to us, the proposed construction consists of a 2-story (upper and lower level) elementary school. We understand that the lower and upper floor elevations are proposed at EL 248 and EL 263, respectively. Maximum cuts and fills of about 8 and 15 feet, respectively, will be required to reach proposed floor grades. Maximum column loads are 260 kips and maximum wall loads are 9 kips/ft.

3.0 Subsurface Conditions

Subsurface conditions were investigated by drilling a total of 14 test borings at the site. Additionally, we excavated a total of three test pits at the site: one test pit to expose the spread footing foundation for the existing gymnasium, and two test pits to observe the depth and consistency of the existing landfill cover materials. Test boring logs, test pit logs, and a boring location plan are presented in Appendix A of this report.

3.1 Geology

The site lies within the Valley and Ridge Physiographic Province of New York. Specifically, according to local geologic maps, the site is mapped in the Pyroxene-hornblende-quartz-plagioclase gneiss of the Middle Proterozoic geologic period.

The existing fill soils of Stratum A are believed to be related to previous site grading. The natural soils assigned to Stratum B are believed to be glacial till deposits. The glacial till deposits are poorly sorted sediments ranging from silts/sands to boulders.

3.2 Stratification

The subsurface materials encountered have been stratified for purposes of our discussions herein. These stratum designations do not imply that the materials encountered are continuous across the site. Stratum designations have been established to characterize similar subsurface conditions based on material gradations and parent geology. The subsurface materials encountered in the test borings completed at the site have been assigned to the following strata:

Stratum A (Existing Fill) loose to very dense, silty sand, clayey sand, poorly graded gravel, FILL, with cobbles, with construction debris at the existing landfill, moist, brown, gray

Stratum B (Glacial Till) generally dense to very dense, silty SAND (SM), silty GRAVEL (GM), POORLY GRADED SAND (SP), and POORLY GRADED GRAVEL (GP), with cobbles, moist, brown, gray, tan

N

December 2, 2014 14214 Page 2

The boulders of Stratum B were cored in test borings B-4, B-5, B-6, B-7, B-8, B-9, B-10, and B-11 to verify that they were boulders and not massive bedrock. Core results are shown on the test boring logs.

The two letter designations included in the strata descriptions presented above and on the test boring logs represent the Unified Soil Classification System (USCS) group symbol and group name for the samples based on laboratory testing per ASTM D-2487 and visual classifications per ASTM D-2488. It should be noted that visual classifications per ASTM D-2488 may not match classifications determined by laboratory testing per ASTM D-2487.

3.3 Groundwater

Groundwater level observations were made in the field during drilling and after completion of the test borings and test pits. Groundwater was encountered at 7 feet depth in TP-1, with no groundwater encountered in the remaining test borings and test pits. Accordingly, groundwater should be below proposed subgrades.

The groundwater observations presented herein are considered to be an indication of the groundwater levels at the dates and times indicated. Fluctuations in groundwater levels should be expected with seasons of the year, construction activity, changes to surface grades, precipitation, or other similar factors.

3.4 Soil Laboratory Test Results

Selected soil samples obtained from the field investigation were tested for grain size distribution, Atterberg limits, and natural moisture contents. A summary of soil laboratory test results is presented below, and the results of natural moisture content tests are presented on the test boring logs in Appendix A.

Test Boring

No.

Depth (ft)

Sample Type Stratum Description of Soil

Specimen

Sieve Results

Atterberg Limits Natural

Moisture Content

Percent Retained #4 Sieve

Percent Passing #200 Sieve

LL PL PI

B-2 8.0-10.0 Jar B silty SAND (SM) 3.6 12.2 NP NP NP 20.0

B-5 6.0-8.0 Jar B

POORLY GRADED

SAND (SP) with silt and gravel

39.0 11.5 NP NP NP 10.3

B-7 4.0-6.0 Jar B silty GRAVEL (GM) with sand 57.3 15.3 NP NP NP 4.3

B-9 2.0-4.0 Jar B

POORLY GRADED

GRAVEL (GP) with silt and sand

66.5 9.5 27 24 3 4.8

B-10 0-2.0 Jar A

POORLY GRADED

GRAVEL (GP-GC) with clay and sand

58.7 11.4 25 21 4 7.2

B-13 0-2.0 Jar A silty SAND (SM) 5.9 20.9 NP NP NP 10.5

B-13 8.0-10.0 Jar A silty SAND (SM) with gravel 35.6 22.7 16 15 1 7.0

B-14 2.0-4.0 Jar A clayey SAND (SC) 10.2 34.3 37 24 13 10.5

Notes:

1. Soil tests are in accordance with applicable ASTM standards

2. Soil classification symbols are in accordance with Unified Soil Classification System

3. Visual identification of samples is in accordance with ASTM D-2488

4. Key to abbreviations: LL = liquid limit; PL = plastic limit; PI = plasticity index; NP = nonplastic

December 2, 2014 14214 Page 3

3.5 Metal Corrosion/Concrete Attack Test Results

In addition to standard geotechnical soil laboratory testing, two samples were submitted to an analytical laboratory for metal corrosion and concrete attack testing. Corrosion testing consisted of analysis for pH (CA643), resistivity (ASTM G187), sulfides (EPA 376.2), and reduction-oxidation potential (Electrode). The results of these tests are presented in the table below:

Test Boring No.

Sample Depth (ft) pH Resistivity

(ohm – cm) Sulfides (mg/kg)

Red-ox Potential (mV)

B-3 0-5 5.7 33,000 <1.2 +250

B-4 0-5 6.0 35,000 <1.2 +270

For each test presented above, points are assigned based on the range of the test results. If the total points from the five tests completed for a particular sample are 10 or more, the soil is considered to be corrosive. The methods described herein are based on information from the American Water Works Association (AWWA). Using the methods described by AWWA, the point total for the samples tested averaged 1. Accordingly, the site soils are considered non-corrosive.

Sulfate (CA 417) and Chloride (CA 422) tests were performed on selected soil samples to determine the severity of sulfate attack on concrete structures. The results of sulfate and chloride testing are presented in the table below.

Test Boring No. Sample Depth (ft)

Sulfate – Water Soluble (mg/kg)

Chloride – Water Soluble (mg/kg)

B-3 0-5 9.2 8.1

B-4 0-5 <5.0 8.3

Based on correlations between sulfate concentrations and severity of sulfate attack as presented in American Concrete Institute (ACI) 318, the above sulfate concentrations are considered to pose a negligible threat of sulfate attack on concrete.

3.6 Seismic Site Classification

A Refraction Microtremor (ReMi) survey was performed at the site to measure the in-situ shear wave velocities of the subsurface, for use in determining the seismic site class in accordance with IBC requirements. The seismic site class definitions based on the weighted average of shear wave velocity in the upper 100 feet of the soil profile are presented in the IBC and are summarized in the table below.

Site Class Soil Profile Name Weighted Average Shear Wave Velocity, sv

(ft/s)

A Hard rock sv > 5,000 ft/s

B Rock 2,500 < sv ≤ 5,000 ft/s

C Very dense soil and soft rock 1,200 < sv ≤ 2,500 ft/s

D Stiff soil profile 600 ≤ sv ≤ 1,200 ft/s

E Soft soil profile sv < 600 ft/s

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The results and location of the seismic shear wave survey are presented in Appendix A of this report and are summarized in the table below.

Seismic Array No.

Weighted Average Shear

Wave Velocity, sv (ft/s) IBC Site Class

L-1 2,562 B

L-2 3,025 B

3.7 Test Pit Investigation

Three test pits were excavated at the site. Two test pits (TP-1 and TP-2) were excavated to evaluate the depth and consistency of the existing landfill cover materials. The landfill cover materials consisted of generally dense, silty sand with gravel that extended to about 4 feet depth, which was underlain by construction debris/landfill materials. Photographs of the test pit excavations are presented below.

TP-1 Excavation

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TP-2 Excavation

One test pit (TP-3) was excavated adjacent to the existing gymnasium to document the depth and dimension of the existing spread footing foundation. The test pit indicated that the bottom of the existing footing was at about 5 feet below existing grade, or at about EL 255.

TP-3 Excavation

0.38 ft

3.1 ft

1.0 ft

1.0 ft

December 2, 2014 14214 Page 6

4.0 Geotechnical Engineering Analysis

Recommendations regarding foundations, lower floor slabs, lateral earth pressures, subdrainage, pavements, earthwork, rock excavation, excavation support/underpinning, stormwater management by infiltration, and potential uses of the existing landfill area are presented herein.

4.1 Spread Footings

Based on the proposed floor elevations, generally dense natural soils or new compacted fill should be encountered at normal spread footing depths. Spread footings founded in these materials are considered suitable for support of the proposed building, and may be designed with a net allowable soil bearing pressure of 3,000 psf. Fill material and compaction requirements are presented in Section 4.5 of this report.

Exterior footing subgrades should be located at least 4 feet below final exterior grades for frost considerations. Individual column footings and continuous wall footings should be at least 30 inches and 18 inches wide, respectively, for local or punching shear considerations. A maximum slope of one horizontal to one vertical (1H:1V) should be maintained between the bottom edges of adjacent footings, including between the new building and the existing gymnasium. Settlement of spread footings should not exceed about 1-inch, and differential settlement between adjacent foundation elements should not exceed about one-half this amount, including not exceeding an angular distortion of 0.002 inch/inch along continuous wall footings.

Footing subgrades should be observed and approved prior to placement of concrete, to ascertain that footings are placed on suitable bearing soils as recommended herein. Footings should be excavated and concrete placed the same day in order to avoid disturbance from water or weather. Disturbance of footing subgrades by exposure to water seepage or weather conditions should be avoided. Any existing fill, disturbed, frozen, or soft subgrade soils should be removed prior to placing footing concrete. Forms may be used if necessary, but less subgrade disturbance is anticipated if excavations are made to the required dimensions and concrete placed against the soil. If footings are formed, the forms should be removed and the excavation backfilled as soon as possible. Water should not be allowed to pond along the outside of footings for long periods of time.

4.2 Lower Floor Slabs on Grade

Lower floor slabs supported by natural soils or new compacted fill are considered feasible at the site. All debris and soft soils near the final floor slab subgrade as a result of construction operations should be stripped and removed prior to placement of underfloor stone. A 4-inch minimum thickness of washed gravel or crushed stone meeting the requirement of AASHTO No. 57 should be placed below floor slabs on grade to serve as a capillary break. This gravel layer will also serve as part of the underfloor subdrainage system. An impermeable plastic membrane should be placed on top of the crushed stone layer to assist as a moisture barrier. Special attention should be given to the surface curing of the slab in order to minimize uneven drying of the slab and associated cracking. Underfloor subdrainage is not recommended since groundwater is expected to be below the lower floor level.

We recommend that mesh (fiber or welded wire fabric) reinforcement be included in the design of the floor slab to minimize the development of any shrinkage cracks near the surface of the slab. If welded wire fabric is used, the mesh should be located in the top half of the slab.

4.3 Lateral Earth Pressures and Subdrainage

Basement walls and site retaining walls should be designed to withstand lateral earth pressures. An equivalent fluid pressure of 60H (psf) should be used for design of basement walls and 42H (psf) for design of site retaining walls, where H refers to the height of the wall. The design should account for any surcharge loads within a 45 degree slope from the base of the wall. Retaining walls may be designed to include a passive equivalent fluid pressure of 375D (psf), where D represents the depth of wall embedment below the exposed wall face. The upper 1.5 feet of soil at the base of retaining walls should not be included in

December 2, 2014 14214 Page 7 the design of passive soil resistance. A coefficient of friction of 0.40 may be used for sliding resistance at the soil/concrete interface. Recommended lateral earth pressure diagrams for use in the design of basement walls and site retaining walls are presented as Figures 2 and 3, respectively, at the end of this report.

Hydrostatic pressures are not included in the lateral earth pressure diagrams assuming the use of relatively granular or free draining backfill, and perimeter subdrainage (weepholes) at the base of walls below grade.

Recommended subdrainage for site retaining walls and basement walls are presented on Figures 3 and 4, respectively, at the end of this report. Recommendations for backfill against walls below grade are presented in Section 4.5 of this report.

4.4 Pavements

Pavement subgrades are expected to consist of firm existing fill, natural soils, or new compacted fill. These materials are generally considered suitable for support of the planned roadways and parking areas.

However, where pavement subgrades consist of existing fill, we recommend budgeting for undercutting the existing fill to a depth of at least 2 feet and backfilling with new compacted fill. The decision to undercut the existing fill should be based on a thorough proofroll of the pavement subgrades under the observation of the geotechnical engineer.

Based on the soil laboratory test results for the materials expected at pavement subgrades, a preliminary design CBR value of 10 is recommended for pavement design purposes. If fill placed at the site is generated from off-site borrow areas, the actual CBR value for the pavement subgrades may be significantly different from the preliminary value presented herein. Therefore, CBR tests should be performed on the in-place subgrade after rough grading and installation of utilities within roadways. Final pavement sections should be based on CBR tests taken on subgrade soils at the time of construction. Concrete pavements should be utilized in loading dock areas and for dumpster pads.

Construction traffic activity on partially constructed pavement sections may result in subgrade and pavement failures due to the reduced support qualities of a partially constructed pavement section and the relatively heavy loads associated with construction traffic. Accordingly, consideration should be given to the construction of designated haul roads where the thickness of the granular subbase and/or asphalt base course has been increased to account for the heavier-loaded construction traffic. We suggest that placement of the asphalt surface course not occur until all the major construction has been completed for pavement areas subjected to construction traffic. To minimize damage to light duty pavement areas during and after construction, consideration should be given to restricting access by construction and any future commercial (non-passenger vehicle) traffic onto the light duty pavement areas, where possible.

The overall grading design should include suitable storm inlets, pavement underdrains, and diversion structures for collecting surface runoff and to limit excessive ponding on paved surfaces. Specific surface drainage recommendations are beyond the scope of our services.

4.5 Earthwork

Fill will be required for site grading in building and pavement areas, and as backfill against walls below grade. The areas to be filled should be cleared and grubbed prior to placing fill. Unsuitable existing fill, soft or loose natural soils, organic material, and rubble should be stripped to approved subgrades as determined by the geotechnical engineer. Topsoil depths presented on the boring logs should not be considered as stripping depths, as topsoil depths may vary widely across the site, particularly in wooded areas. Stripping depths will probably extend to greater depths than the topsoil depths indicated herein due to the presence of minor amounts of organics, roots, and other surficial materials that will require removal as a part of the stripping operations. In addition, seasonal soil moisture variations can affect stripping depths. In general, less stripping may occur during summer months when drier weather conditions can be expected The depth of required stripping should be determined prior to construction by the excavation contractor using test pits, probes, or other means that the contractor wishes to employ, and this determination should be the responsibility of the excavation contractor. All subgrades should be proofrolled

December 2, 2014 14214 Page 8 with a minimum 20 ton, loaded dump truck or suitable rubber tire construction equipment approved by the geotechnical engineer, prior to the placement of new fill.

For building areas, the new fill should extend at least 10 feet outside building lines. For parking areas, the new fill should extend at least 5 feet outside pavement edges. These recommendations are illustrated by Figure 5 at the end of this report.

Fill material should be placed in lifts not exceeding 8 inches loose thickness, with fill materials compacted by hand operated tampers or light compaction equipment placed in maximum 4-inch thick loose lifts. Fill should be compacted at +/- 2% of the optimum moisture content to at least 95 percent of the maximum dry density per ASTM D-698. The upper 6 inches of pavement subgrades should be compacted to at least 100 percent of the maximum dry density per the same standard.

Fill placed along slopes steeper than 5H:1V should be benched into the existing slope. Benches should consist of minimum 8 feet wide level cut, and at least one such bench should be used for each 3 feet of vertical rise of fill placed.

Materials used for compacted fill for support of footings, floor slabs, and pavements should consist of soils classifying SM, SP, SW, GM, GP, or GW per ASTM D-2487, with a liquid limit and plasticity index less than 40 and 15, respectively. It is expected that the majority of soils excavated at the site will be suitable for re-use as fill based on classification. However, the Stratum A existing fill may not be suitable for re-use as new compacted fill due to deleterious man-made materials in the fill. In addition, drying of excavated soils by spreading and aerating may be necessary to obtain proper compaction. This may not be practical during the wet period of the year. Accordingly, earthwork operations should be planned for early Spring through late Fall, when drier weather conditions can be expected.

Fill materials should not be placed on frozen or frost-heaved soils, and/or soils that have been recently subjected to precipitation. All frozen or frost-heaved soils should be removed prior to continuation of fill operations. Borrow fill materials should not contain frozen materials at the time of placement.

Compaction equipment that is compatible with the soil type used for fill should be selected. Theoretically, any equipment type can be used as long as the required density is achieved; however, sheepsfoot roller equipment are best suited for fine-grained soils and vibratory smooth drum rollers are best suited for granular soils. Ideally, a smooth drum roller should be used for sealing the surface soils at the end of the day or prior to upcoming rain events. In addition, compaction equipment used adjacent to walls below grade should be selected so as to not impose undesirable surcharge on walls. All areas receiving fill should be graded to facilitate positive drainage of any water associated with precipitation and surface run-off.

For utility excavation backfill, we recommend that open graded stone be used to backfill the pipe trench to the spring line of the pipe. Backfill should be compacted in lifts not exceeding 6 inches loose thickness, to at least 95 percent of the maximum dry density per ASTM D-698. Hand operated compaction equipment should be used until the backfill has reached a level 1 foot above the top of the pipe to prevent damaging the pipe. Also, backfill material within 2 feet of the top of the pipe should not contain rock fragments or gravel greater than 1-inch in diameter.

After completion of compacted fill operations in building or pavement areas, construction of building elements or asphalt should begin immediately, or the finished subgrade should be protected from exposure to inclement weather conditions. Exposure to precipitation and freeze/thaw cycles will cause the finished subgrade to soften and become excessively disturbed. If development plans require that finished subgrades remain exposed to weather conditions after completion of fill operations, additional fill should be placed above finished grades to protect the newly placed fill. Alternatively, a budget should be established for reworking of the upper 1 to 2 feet of previously placed compacted fill.

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4.6 Rock Excavation

The majority of excavations to reach proposed building and pavement grades should generally be feasible using normal earth moving equipment; however, rock excavation methods such as hoe-ramming or blasting may be required for some of the site excavations to remove boulders. It appears that depth to bedrock averages 30 feet below the existing ground surface based on interpreting the Shear Wave Velocity test data.

Test Boring No. Estimated Elevation Where Rock Excavation Methods May be Required to Remove Boulders

B-1 EL 260

B-2 EL 257

B-3 EL 230

B-4 EL 248

B-5 EL 235

B-6 EL 264

B-7 EL 241

B-8 EL 258

B-9 EL 275

B-10 EL 258

B-11 EL 249

B-13 EL 221

The elevations given above are based upon the use of normal earth excavation equipment including up to a Caterpillar 330 hydraulic backhoe or equivalent, for mass excavation. Project specifications should include the following as a definition of rock excavation for mass excavation: “Rock is defined as any material which cannot be dislodged by a Caterpillar 330 hydraulic backhoe without the use of hoe-ramming or blasting.

This classification does not include material such as loose rock, concrete or other materials that can be removed by means other than hoe-ramming or blasting, but which for reasons of economy in excavating, the contractor chooses to remove by hoe-ramming or blasting.”

Requirements for blasting boulders should be determined by a contractor with demonstrated experience in this work. Consideration must be given to vibrations transmitted to nearby buildings in determining the size of charges that may be detonated at one time. The specifications should require the taking of seismograph readings at adjacent structures to develop a blast plan that produces an acceptable level of vibrations. Each blast should be contained or covered to minimize air blast and flyrock. A precondition survey of nearby structures should be made prior to the start of construction to document the existing conditions.

4.7 Excavation Support/Underpinning

The excavations may be constructed by laying back the earth with temporary slopes. Temporary excavations that may occur will generally extend through sandy soils. Based on the on-site soils, an OSHA type C soil classification should be used for design of earth slopes, which requires a maximum allowable slope of 1.5H:1V. Any benching of excavations should be performed in accordance with OSHA

December 2, 2014 14214 Page 10 requirements. A 2H:1V slope or flatter should be maintained between the bottom edge of footings for any existing structures and the top of adjacent excavation slopes.

It will be necessary to underpin the existing gymnasium building where the lower floor level of the proposed elementary school abuts the gymnasium, to transfer building loads below excavation levels. Underpinning of the existing foundations using traditional pit type construction should be feasible. The pits should be sized with an allowable soil bearing pressure of 3,000 psf when founded on the dense silty sand soils of Stratum B. There is a risk of additional building movements during the underpinning procedure. The excavations for underpinning should be completed in relatively short lengths to minimize damage to the existing building. Maximum lengths of underpinning pits should be provided by the structural engineer.

The underpinning work should be completed by a specialty contractor with demonstrated experienced in this kind of work. The subgrade for each pit should be observed by a geotechnical engineer to verify conditions are similar to those assumed in this analysis and to confirm construction is performed consistent with these recommendations.

4.8 Infiltration Analysis

Two methods were used to estimate infiltration capabilities on the subject site: in-situ infiltration testing and published correlations with soil classifications. Details regarding the in-situ infiltration and classification test techniques, the estimated infiltration rates from the individual methods, and the recommended design infiltration rate for the site soils are presented herein.

4.8.1 Infiltration Test Results

In-situ infiltration tests are performed in the field to observe the rate at which water will permeate the soil under saturated conditions. Four test borings were drilled in the area of planned infiltration. Test borings were initially drilled to depths of at least 4 feet below the planned infiltration invert elevations, and allowed to remain open for a period of approximately 24 hours to allow any groundwater levels within the boreholes to stabilize. After 24 hours, offset infiltration test holes were drilled at the boring locations to planned infiltration invert elevations. Four-inch diameter PVC casing was set to the bottom of the test holes. The purpose of the casing is to prevent caving of test hole sidewalls. After setting the PVC casing, the borehole was filled with water to saturate the bottom subsoils. The following day, the test hole was refilled with water and the water level in each test hole was recorded every hour for a 4-hour period. Using this procedure, the average change in the water level over the 4-hour period is considered the infiltration rate.

Based on the results of the in-situ infiltration tests, estimated infiltration rates have been assigned for the site soils, as presented in the table below:

Test Boring No. Approximate Test Depth (ft) Estimated Infiltration Rate (inches/hour)

B-7 2.0 >24

B-9 10.0 >24

B-10 5.0 >24

B-11 2.0 18.5

4.8.2 Classification Test Results

The classification test method is performed with grain-size sieve analyses including hydrometer testing on samples obtained from corresponding proposed infiltration depths, to determine the USDA soil texture classifications. Published correlations between USDA classifications and infiltration rates were used to provide estimated hydraulic conductivity values. Published correlations between USDA classifications and infiltration rates were used to estimate rates as presented herein.

December 2, 2014 14214 Page 11

Test Boring No.

Approximate Test Depth (ft)

USDA Soil Texture Classification

Estimated Infiltration Rate (inches/hour)

B-10 5 Sandy loam 1.02

B-10 9 Loamy sand 2.41

B-11 2 Sandy loam 1.02

B-11 6 Sandy loam 1.02

4.8.3 Recommended Design Infiltration Rate

Based on the results of the in-situ infiltration tests and soil laboratory classification tests, we recommend that a design infiltration rate of 1.02 inches/hour be used for design of infiltration structures. It should be noted that the recommended design infiltration rate presented herein is intended for use in design.

However, during construction, observations of the subgrade conditions should be made to confirm that the subgrade soils are consistent with the soils analyzed in this report.

4.9 Landfill Use Comments

Three test borings and two test pits were excavated in the existing landfill area. The landfill cover materials consisted of generally dense, silty sand with gravel that extended to about 4 feet depth, which was underlain by construction debris/landfill materials. The landfill area may be utilized as recreational fields/courts, but is not suitable to support a building/structure. None of the cover material should be removed or excavated for any further site development in this area. The use of heavy equipment on the landfill surface should also be avoided so that it does not leave ruts or tear up the existing landfill cover.

5.0 Environmental Analysis

Due to the known existence of a closed landfill abutting the proposed school building site, test borings performed adjacent to the existing landfill were screened with a Photoionization Detector (PID) during drilling, chemical laboratory analyses was performed on selected soil samples, and wells were monitored for methane during the field investigation. Details of our field investigation and test results are presented below.

5.1 PID Screening

An OSHA-trained environmental staff engineer was on-site during drilling of test borings B-3 and B-5 to screen soil samples with a Photoionization Detector (PID) to detect the presence of volatile organic compounds (VOCs). No petroleum odors or elevated PID readings were noted during drilling of these test borings. The PID readings are indicated on the test boring logs in Appendix A.

5.2 Methane Monitoring

A 4-in-1 multi-meter was utilized to detect the presence of landfill gas during and after drilling of all test borings. In test borings B-3 and B-5, a 1-inch diameter machine slotted PVC pipe was installed, and the annular space was backfilled with filter sand and capped with bentonite to the surface. Each PVC pipe was then capped with a valve fitted for a GEM2000 landfill gas meter so measurements could be completed over a 7-day period. No measurable amount of methane was detected in any of the boreholes.

5.3 Chemical Laboratory Test Results

Select jar grab soil samples obtained during the field investigation were sent to HP Environmental for analysis of Total Petroleum Hydrocarbons-Diesel Range Organics (TPH-DRO), Total Petroleum Hydrocarbons-Gasoline Range Organics (TPH-GRO), RCRA metals, Volatile Organic Compounds (VOCs), December 2, 2014 14214 Page 12 polycyclic aromatic hydrocarbons (PAHs), and polychlorinated biphenyl (PCBs). Each sampling jar was labeled with the project name, the project number, the date, the test boring number, the testing parameters, and the depth from which the sample was collected. The jar samples were placed in a cooler on ice and remained chilled until transported to the chemical laboratory under chain-of-custody procedures for analysis. Laboratory test methods are listed in the table below.

Parameter Matrix Laboratory Test Method

TPH-DRO Soil EPA 8015

TPH-GRO Soil EPA 8015

RCRA Metals Soil EPA 6010

VOCs Soil EPA 8260

PAHs Soil EPA 8270

PCBs Soil EPA 8082

A summary of soil laboratory test results is presented in the table below. Copies of the analytical test results for the soil samples are included in Appendix B.

Te st

B or in g

N o.

D ep th B el ow

Ex is ti ng

G ro un d

Su rf ac e

(f t)

TP

H

-D R

O

(m g/ kg

TP

H

-G R

O

(m g/ kg

R C

R A m et al s

(m g/ kg

V O

C s

(µ g/ kg

P A

H s

(µ g/ kg

P C

B s

(µ g/ kg

B-3 8-10 46 ND Barium: 38 Chromium: 8.6 ND ND ND

B-5 2-4 7.7 ND

Barium: 29

Chromium: 10 Lead: 3.3

ND

Phenanthrene: 65 Anthracene: 79

Fluoranthene: 97 Pyrene: 71

ND

B-7 0-2 8.7 ND

Barium: 55

Chromium: 16 Lead: 20

ND

Phenanthrene: 36 Fluoranthene: 63

Pyrene: 56

ND

ND = Non-Detect

The New York State Department of Environmental Conservation’s Petroleum-Contaminated Soil Guidance Policy indicates Soil Cleanup Objectives for select parameters. However, none of the parameters that were detected in samples from the site (TPH-DRO, barium, chromium, lead, phenanthrene, anthracene, fluoranthene, or pyrene) are included in the tables of soil cleanup levels. Therefore, we referred to the EPA Regional Screening Level Summary Table to assess the concentrations of tested parameters. All parameters are well below the EPA Screening Levels, including chromium when comparing the test results to the probable occurring chromium III screening levels.

5.4 Recommendations

Due to the limited testing locations and the nature of the proposed building being a school, and the fact that there is an adjacent landfill, we recommended that a passive soil gas management and ventilation system be installed under the floor slab for the lower floor level. The passive system should consist of venting via PVC pipe from the underslab gravel layer. The gravel layer should be a minimum of 4 inches thick as per the previous geotechnical engineering recommendations. Additionally, a vapor barrier rated for methane gas should be installed under the floor slab for the lower floor level.

December 2, 2014 14214 Page 13

6.0 General Limitations

Recommendations contained in this report are based upon the data obtained from the relatively limited number of test borings and test pits. This report does not reflect conditions that may occur between the points investigated, or between sampling intervals in test borings. The nature and extent of variations between test borings and test pits and sampling intervals may not become evident until the course of construction. Therefore, it is essential that on-site observations of subgrade conditions be performed during the construction period to determine if re-evaluation of the recommendations in this report must be made. It is critical to the successful completion of this project that GeoConcepts be retained during construction to observe the implementation of the recommendations provided herein.

This report has been prepared to aid in the evaluation of the site and to assist your office and the design professionals in the design of this project. It is intended for use with regard to the specific project as described herein. Changes in proposed construction, grading plans, structural loads, etc. should be brought to our attention so that we may determine any effect on the recommendations presented herein.

An allowance should be established for additional costs that may be required for foundation and earthwork construction as recommended in this report. Additional costs may be incurred for various reasons including wet fill materials, soft subgrade conditions, unexpected groundwater problems, rock excavation, etc.

This report should be made available to bidders prior to submitting their proposals to supply them with facts relative to the subsurface conditions revealed by our investigation and the results of analyses and studies that have been performed for this project. In addition, this report should be given to the successful contractor and subcontractors for their information only.

We recommend the project specifications contain the following statement: “A geotechnical engineering report has been prepared for this project by GeoConcepts Engineering, Inc. This report is for informational purposes only and should not be considered part of the contract documents. The opinions expressed in this report are those of the geotechnical engineer and represent their interpretation of the subsoil conditions, tests and results of analyses that they performed. Should the data contained in this report not be adequate for the contractor’s purposes, the contractor may make their own investigations, tests and analyses prior to bidding.”

This report was prepared in accordance with generally accepted geotechnical engineering practices. No warranties, expressed or implied, are made as to the professional services included in this report.

December 2, 2014 14214 Page 14

We appreciate the opportunity to be of service for this project. Please contact the undersigned if you require clarification of any aspect of this report.

Sincerely, GEOCONCEPTS ENGINEERING, INC.

Katherine Fordney Staff Engineer

Paul E. Burkart, PE Principal

KF/AH/PEB/shm N:\PROJECTS\Active 14 Projects\14214, West Point\Final\GER.docx

December 2, 2014 14214 Page 15

Appendix A Subsurface Investigation Subsurface Investigation Procedures (1 page)

Identification of Soil (1 page)

Test Boring and Test Pit Notes (1 page)

Test Boring Logs (14 pages)

Test Pit Logs (3 pages)

Boulder Core Pictures (2 pages)

In-situ Shear Wave Test Procedures (1 page)

In-Situ Shear Wave Velocity Test Data (2 pages)

Boring Location Plan, Figure 5 (1 page)

Subsurface Investigation Procedures

1. Test Borings – Cased Borings The borings are advanced by driving casing to the sampling depth. Soil within the casing is cleaned out by chopping or rotary drilling, using wash water to remove cuttings. Casing is generally advanced only to the depth necessary to prevent caving of the boring sidewalls.

2. Standard Penetration Tests Standard penetration tests are performed by driving a 2 inch O.D., 1-⅜ inch I.D. sampling spoon with a 140-pound hammer falling 30 inches, according to ASTM D-1586. After an initial 6 inches penetration to assure the sampling spoon is in undisturbed material, the number of blows required to drive the sampler an additional 12 inches is generally taken as the N value. In the event 30 or more blows are required to drive the sampling spoon the initial 6-inch interval, the sampling spoon is driven to a total penetration resistance of 100 blows or 18 inches, whichever occurs first. The sampling operation is terminated after a total of 100 hammer blows and the depth of penetration is recorded.

3. Boulder Core Drilling Boulders were cored using drilled using NQ size core bits set with carbide steel or diamond, depending upon the rock texture. The bit is fitted onto a double tube swivel-type core barrel in which an exterior tube and bit rotate, and an interior barrel remains stationary to receive the core. Water is circulated between the barrels and across the bit face to cool the core bit and to flush away cuttings.

4. Test Pits Test pits were excavated using a CAT 420 backhoe with a 6-inch wide bucket attachment. Test pits were excavated to a maximum depth of 7 feet below the existing ground surface. On completion of the test pit observations, test pits were backfilled with excavated soil material to existing grades. It should be noted that although some effort to compact backfill soils in test pit excavations was made during the field investigation, some settlement of test pit backfill materials should be expected.

5. Test Boring and Test Pit Stakeout The test boring and test pit stakeout was provided by the project civil engineer.

Identification of Soil I. DEFINITION OF SOIL GROUP NAMES ASTM D-2487 Symbol Group Name

Coarse-Grained Soils More than 50% retained on No. 200 sieve

Gravels More than 50% of coarse fraction retained on No. 4 sieve

Clean Gravels Less than 5% fines

GW WELL GRADED GRAVEL

GP POORLY GRADED GRAVEL

Gravels with Fines More than 12% fines

GM silty GRAVEL GC clayey GRAVEL

Sands 50% or more of coarse fraction passes No. 4 sieve

Clean Sands Less than 5% fines

SW WELL GRADED SAND

SP POORLY GRADED SAND

Sands with fines More than 12% fines

SM silty SAND SC clayey SAND

Fine-Grained Soils 50% or more passes the No. 200 sieve

Silts and Clays Liquid Limit less than

Inorganic CL LEAN CLAY

ML SILT

Organic OL ORGANIC CLAY

ORGANIC SILT

Silts and Clays Liquid Limit 50 or more

Inorganic CH FAT CLAY

MH ELASTIC SILT

Organic OH ORGANIC CLAY

ORGANIC SILT

Highly Organic Soils Primarily organic matter, dark in color, and organic odor PT PEAT

II. DEFINITION OF MINOR COMPONENT PROPORTIONS

Minor Component Approximate Percentage of Fraction by Weight Gravelly, Sandy (adjective) 30% or more coarse grained Sand, Gravel 15% to 29% coarse grained Silt, Clay 5% to 12% fine grained

III. GLOSSARY OF MISCELLANEOUS TERMS

SYMBOLS Unified Soil Classification Symbols are shown above as group symbols. Use “A” Line Chart for laboratory identification. Dual symbols are used for borderline classification.

BOULDERS & COBBLES Boulders are considered pieces of rock larger than 12 inches, while cobbles range from 3 to 12 inches.

WEATHERED ROCK Residual rock material with a standard penetration test (SPT) resistance of at least 60 blows per foot.

ROCK/SPOON REFUSAL Rock material with a standard penetration test (SPT) resistance of 50 blows for 1 inch.

ROCK FRAGMENTS Angular pieces of rock which have separated from original vein or strata and are present in a soil matrix. Only used in residual soils QUARTZ A hard silicate mineral often found in residual soils. Only used when describing residual soils.

CEMENTED SAND Usually localized rock-like deposits within a soil stratum composed of sand grains cemented by calcium carbonate, iron oxide, or other minerals. Commonly encountered in Coastal Plain sediments, primarily in the Potomac Group sands (Kps).

MICACEOUS A term used to describe soil that “glitters” or is shiny. Most commonly encountered in fine-grained soils.

ORGANIC MATERIALS

(Excluding Peat)

Topsoil - Surface soils that support plant life and contain organic matter.

Lignite - Hard, brittle decomposed organic matter with low fixed carbon content (a low grade of coal).

FILL Man-made deposit containing soil, rock, and other foreign matter.

CONTAINS This is used when a fill deposit contains a secondary component that does not apply to a USCS classification. Only used for fill deposits WITH This is used when a residual soil contains a secondary component that does not contribute to its USCS classification. Only used for natural soils.

PROBABLE FILL Soils which contain no visually detected foreign matter but which are suspect with regard to origin.

LAYERS ½ to 12 inch seam of minor soil component.

COLOR Two most predominant colors present should be described.

MOISTURE CONDITIONS Wet, moist, or dry to indicate visual appearance of specimen.

Test Boring and Test Pit Notes

1. Classification of soil is by visual inspection and is in accordance with the Unified Soil Classification

System.

2. Estimated groundwater levels are indicated on the logs. These are only estimates from available data and may vary with precipitation, porosity of soil, site topography, etc.

3. Sampling data presents standard penetrations for 6-inch intervals or as indicated with graphic representations adjacent to the sampling data.

4. The logs and related information depict subsurface conditions at the specific locations and at the particular time when drilled. Soil conditions at other locations may differ from conditions occurring at the test locations. Also, the passage of time may result in a change in the subsurface conditions at the test locations.

5. The stratification lines represent the approximate boundary between soil types as determined in the sampling operation. Some variation may be expected vertically between samples taken. The soil profile, groundwater level observations and penetration resistances presented on the logs have been made with reasonable care and accuracy and must be considered only an approximate representation of subsurface conditions to be encountered at the particular location.

6. Test pit excavations are logged to provide a record for geotechnical evaluation, construction inspection or other specialized purpose. Any significant features such as existing fill conditions, underground structures, groundwater or water seepage conditions, etc. are recorded.

7. Rock Quality Designation (RQD) represents the sum of cores recovered with lengths of 4-inches or longer, divided by the total length of rock core, expressed in percentage.

8. The information presented in the PID column are the results of photoionization detector (PID) screening of the soil samples obtained in the test borings. The PID is used to provide a qualitative indication of the presence of volatile organic compounds (VOC’s). However, in order to obtain a quantitative indication of VOC’s, chemical analytical testing is required.

14+24+24+27

30+24+30+36

28+50/5

44+50/3

50/5

50/5

16+50/4

26+50/5

B

Topsoil = 0.17ft.

Glacial till, brown and gray, f, silty SAND with gravel, dense, moist, SM

Very dense

Brown, f-c

Brown and gray, f, with cobbles

Brown

Bottom of Boring at 24.4 ft

265.0 264.8

263.0

259.0

256.5

251.5

DRILLING METHOD: OFFSET NOTES:

4" Dia Rotary, Auto Hammer

PROJECT NUMBER:

EwingCole

14214

T. Van Ness

265.0 ±

DATES DRILLED:OWNER/CLIENT:

GROUND SURFACE ELEVATION (ft):

DRILLER:

10/27/14 - 10/27/14

Offset 45.0 ft. south due to boulders and slope.

West Point Elementary School

US Military Academy, West Point, New York

THE STRATIFICATION LINES REPRESENT APPROXIMATE BOUNDARIES. THE TRANSITION MAY BE GRADUAL.

SAMPLE TYPES:

Split Spoon

Backfilled upon completion.

Aquifer Drilling and Testing, Inc.

K. Fordney

B-1DRILLING CONTRACTOR:

BORING NUMBER:

SHEET 1 OF 1

LOCATION:

LOGGED BY:PROJECT:

GROUND WATER LEVELS:

REMARKS:

SOIL

MATERIAL DESCRIPTION

NOT ENCOUNTERED UPON COMPLETION

NOT ENCOUNTERED DURING DRILLING

19955 Highland Vista Dr., 170 Ashburn, Virginia 20147

703-726-8030 703-726-8032 fax

B O

R E

H O

LE

/T

E S

T P

IT

L

O G

S .G

P J

T R

A

IN

IN

G

_1

4A .G

P J

1/

4/

SPT

BLOW

COUNTS R

E

C (in

20 40 60 80

STANDARD

PENETRATION

TEST RESISTANCE

(BPF)

DEPTH

(ft)

S T