1565917 spc 1of1_appendix b.pdf

P-898 Replace SSN Berthing Pier 32 eProject No. 1565917

Naval Submarine Base New London - Groton, CT

Appendix B

APPENDIX B

Geotechnical Engineering Report

P-898 Replace SSN Berthing Pier 32

This page was intentionally left blank for duplex printing.

www.haleyaldrich.com

FINAL GEOTECHNICAL ENGINEERING REPORT

P-898 REPLACE SSN BERTHING PIER 32

NAVAL SUBMARINE BASE NEW LONDON

GROTON, CONNECTICUT

by Haley & Aldrich, Inc.

Manchester, New Hampshire for MN- FST Joint Venture Norfolk, Virginia

File No. 128833-004 November 2019

HALEY & ALDRICH, INC.

3 Bedford Farms Drive Bedford, NH 03110 303.625.5333 www.haleyaldrich.com

Revised 12 November 2019 7 November 2019 File No. 128833-004

MN- FST Joint Venture 800 World Trade Center Norfolk, Virginia 23510

Attention: Mikele Winters

Subject: Final Geotechnical Engineering Report

P898 Replace SSN Berthing Pier 32 Naval Submarine Base New London

Groton, Connecticut

Ladies and Gentlemen:

This report summarizes the geologic background, historic subsurface explorations, recent subsurface explorations, subsurface conditions, and geotechnical design recommendations and construction considerations related to the geotechnical aspects of the project. This report has been prepared in accordance with our proposal dated 15 October 2018, and your subsequent authorization. The work has been conducted under the Contract No. N40085-14-D-8113.

Sincerely yours, HALEY & ALDRICH, INC.

Philip J. Dunaj, P.E.

Senior Geotechnical Engineer

John G. DiGenova, P.E.

Associate

Enclosures

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Table of Contents Page

List of Figures iv

1. Introduction 1

1.1 GENERAL 1

2. Regional Geology 4

3. FIELD AND LABORATORY INVESTIGATIONS 5

3.1 HISTORIC SUBSURFACE EXPLORATIONS 5

3.1.1 ORIGINAL PIER 31 5

3.1.2 PIER 31 REPLACEMENT 5

3.1.3 ORIGINAL PIER 32 5

3.1.4 ORIGINAL PIER 33 5

3.2 RECENT SUBSURFACE EXPLORATIONS 5

3.3 TEST BORINGS AND PROBES 5

3.3.1 Waterside – Pier 32 5

3.3.2 Landside – Crane Weight Test Area, Pier 32, and Pier 17 Stub 6

4. Generalized Subsurface Conditions 7

5. Geotechnical Laboratory Testing 9

6. Geotechnical Design Recommendations 10

6.1 PIER 32 10

6.1.1 DRILLED SHAFT FOUNDATION DESIGN CRITERIA 10

6.1.2 DRIVEN PIPE PILES 11

6.1.3 Fender Piles 13

6.1.4 Crane Weight Test Area 13

6.1.4.1 Soil Parameters Landside of Quay Wall 13

6.1.5 EQUIPMENT PLATFORM FOUNDATIONS 13

6.2 LATERAL RESISTANCE 14

6.3 SITE SPECIFIC SEISMIC RESPONSE 14

6.4 SEISMIC SITE CLASS 15

6.5 LIQUEFACTION 15

7. Geotechnical Construction Consideration 16

7.1 GENERAL 16

7.2 EARTHWORK 16

7.2.1 MASS EXCAVATION 16

7.2.2 PREPARATION AND PROTECTION OF BEARING SURFACES 16

Table of Contents Page

7.2.3 BACKFILLING 17

7.3 DRILLED SHAFTS 18

7.4 PILE DRIVING 18

Figures Appendix A – Historic Test Boring Logs and Locations Appendix B – Recent Boring Logs Appendix C – Laboratory Testing Results Appendix D – Calculations iv

List of Figures

Figure No. Title

1 Project Locus

2A Site and Subsurface Exploration Plan

2B Site and Subsurface Exploration Plan

3 Approximate Top of Rock Contour Plan

4 Geologic Profile A-A

5 Geologic Profile B-B

1. Introduction

1.1 GENERAL

This report presents the results of our subsurface exploration program and provides geotechnical engineering recommendations for the P-898 Replace SSN Berthing Pier 32 located at the Naval Submarine Base New London – Groton, Connecticut. This report has been prepared in accordance with our proposal dated 15 October 2018, and your subsequent authorization. The work has been conducted under the Contract No. N40085-14-D-8113.

1.2 PURPOSE AND SCOPE

Our scope included performing subsurface explorations to geotechnically characterize subsurface conditions, performing engineering analyses using the data obtained, and preparing this report summarizing our recommendations for foundation and geotechnical design and construction for the proposed project. The scope of our work included the following:

Planning and monitoring a geotechnical subsurface exploration program;

Making engineering interpretations of the subsurface data;

Performing geotechnical engineering evaluations;

Developing geotechnical engineering recommendations; and Summarizing our subsurface explorations, engineering evaluations, and recommendations in this report.

1.3 ELEVATION DATUM

All elevations noted herein are in feet and reference the North American Vertical Datum of 1988

(NAVD88).

1.4 SITE AND EXISTING CONDITIONS

As shown on Figure 1 – Project Locus, the Pier 32 site is located at the Naval Submarine Base New London in Groton, Connecticut. The naval base is north of Interstate 95, east of the Thames River which runs north-south, and west of State Road 12. The proposed Pier 32 location is at the northern end of the base and is accessible by the lower base along Amberjack Road. The new pier will be located 150 ft north of existing Pier 32. The pier will provide two berths for SSN 774 (Virginia Class) and SSN 688 (Los Angeles Class) submarines for general berthing and maintenance. The height of water above the existing mudline is generally around 35 ft for most of the proposed pier.

The project also includes sequence demolition of existing piers 10, 32, and 17; and reconstruction of a section of the quaywall near the crane weight test area. In general, these areas are accessible by Amberjack Road. Multiple underground utilities are located below the paved area at these locations.

Note that the proposed crane weight test area is located in the base Installation Restoration (IR) Zone 5;

Pier 32 is located in IR Zone 6; and Pier 10 and 17 is located in IR Zone 7.

1.5 PROPOSED CONSTRUCTION

In addition to replacement of Pier 32, the project will also include the following:

Sequenced demolition of existing piers 10, 32, and 17 stub;

Dredging and disposal;

New crane weight test pads; and Reinforcement of Quaywall at Crane Weight Test Area.

The proposed Pier 32 will be constructed about 150 ft north of the existing Pier 32 and west of existing Building 174 and will extend into the Thames River. The new pier will be about 561 ft long and 67 ft wide. The deck is planned to be supported by 24 bents, with each bent consisting of 5 foundation elements. The deep foundation system will consist of 36-in. diameter drilled shafts (47 elements) into bedrock and 36-in. diameter pipe piles (70 elements) driven to bedrock. Fender piles are also part of the proposed construction consisting of an upper fiberglass section and lower H-pile section. New equipment platforms and vault structures are planned on the landside of the new Pier.

We understand the maximum service loads on the Pier 32 deep foundation elements are as follows:

Maximum Compression Load: 671 kips Maximum Tension/Uplift Load: 0 Maximum Lateral Displacement: 5 in.

Driven pipe piles have a pile fixity at El. -64 and a second point of zero deflection at El -121.

The H-piles for support of the fenders shall be installed to have an ultimate compressive capacity of 135 kips.

A portion of the quaywall apron at the crane weight test area will be strengthened in order to accommodate the relocations of crane test weights that are currently stored in the area where the new pier will be constructed. As part of the quaywall strengthening, a segment of existing pile-supported structure will be demolished and reconstructed so that it can support the required loads. Drilled shafts are planned at this location. In addition, two concrete slabs on-grade will be constructed to assist with crane test weight operations.

1.6 LIMITATIONS

This report has been prepared for specific application to the project as it is planned at this time and is limited to the P-898 Replace SSN Berthing Pier 32 located at the Naval Submarine Base New London – Groton, Connecticut. In the event that changes in the nature, design, or location of structures are planned, the conclusions and recommendations contained in this report should not be considered valid unless the changes are reviewed and conclusions of this report modified or verified in writing. The analyses and recommendations submitted in this report are based in part upon data obtained from referenced explorations. The nature and extent of variations between the explorations may not become evident until construction. If variations then appear evident, it will be necessary to re-evaluate the recommendations of this report.

This report is prepared for the exclusive use of Moffatt & Nichol and its design team in connection with the geotechnical aspects of the project. Recommendations presented in this report address only the conventional geotechnical engineering related aspects of design and construction.

2. Regional Geology

The Naval Submarine Base New London is located on the east side of the Thames River tidal estuary, a north-south trending deep river valley that drains eastern Connecticut and central Massachusetts. As one of the deepest natural harbors on the Atlantic Coast, the south-draining Thames River flows past New London into Long Island South.

The bedrock in the vicinity of the site is mapped as a complex of folded metamorphic gneisses with bodies of granite, amphibolite, and quartzite identified within the gneiss terrain. The structural bedrock grain trends northwest-to-southeast with foliation that dips steeply into the northeast, oblique to the linear trend of the Thames River. Due to the alternating layers of rock with differing composition and hardness, the bedrock surface elevation in proximity to the site is undulating and quite variable.

Bedrock is exposed on the west side of the Thames River near Scotch Cap Road and Smith Cove. Within the Naval Base itself, bedrock is exposed on the golf course immediately east of the proposed Pier 32 location and the Providence & Worcester railroad tracks. The bedrock surface below the Thames River, however, slopes steeply down in elevation from the flanks along the river. The deepest bedrock surface is over 200 ft below sea level based on explorations performed by others. This overdeepened rock valley may be the result of a series of downdropped fault blocks, a north-south aligned fault zone, or a pre-glacial regional drainage system that was superimposed and, over time, eroded down into the oblique rock structure.

Overburden (soil) deposits identified above the bedrock surface consist of a dense, boulder glacial till, thick granular glaciofluvial meltwater deposits from the retreat of the melting ice margin, and more recent (Holocene) deposits of very thick, soft organic sediments and peats. The fill soils or disturbed materials related to the construction of the dockside and pier structures at the Naval Base are present in proximity to the proposed Pier 32 structures.

3. FIELD AND LABORATORY INVESTIGATIONS

3.1 HISTORIC SUBSURFACE EXPLORATIONS

A number of historic explorations have been completed at the site under various contracts. Relevant geotechnical subsurface information between 1971 to 2007 was made available to Haley & Aldrich. The number of explorations from each contract/year mentioned below includes only the explorations relevant to the areas of interest for the new construction under the current contract N40085-14-D-8113.

3.1.1 ORIGINAL PIER 31

Seven test borings were performed around 1971 as part of the contract N-62472-71-C-0201 for the construction of Pier 31.

3.1.2 PIER 31 REPLACEMENT

Seven test borings and three probes were performed during the period December 2003 to February 2004 and November 2007 as part of the contract N-40085-09-C-7011 for the replacement of Pier 31.

The test borings were performed by Geologic Earth Exploration Inc., formerly of Wrentham, Massachusetts.

3.1.3 ORIGINAL PIER 32

Fourteen test borings were performed around 1976 as part of the contract N-62472-74-C-0343 for the construction of Pier 32.

3.1.4 ORIGINAL PIER 33

Six test borings were performed around 1978 as part of the contract N-62472-77-C-0405 for the construction of Pier 33.

The historic boring locations and logs are presented in Appendix A.

3.2 RECENT SUBSURFACE EXPLORATIONS

3.3 TEST BORINGS AND PROBES

3.3.1 Waterside – Pier 32

Haley & Aldrich conducted a subsurface exploration program consisting of nine test borings, designated HA17-B1 through HA17-B8 (including HA17-B4A) and three test probes designated HA17-P1 through HA17-P3 at the locations shown on Figure 2A. The nine test borings were drilled between 12 April to 15 September 2017 by Geologic Earth Exploration, Inc. of Norfolk, Massachusetts. The borings were drilled over water to depths ranging from approximately 61 to 156 ft below mudline. The test probes were drilled between 18 to 26 September 2017 by Geologic Earth Exploration, Inc. of Norfolk, Massachusetts.

The probes were drilled over water to depths ranging from 20 to 142 ft below mudline. No soil samples or rock cores were collected during the test probe program.

To obtain soil samples, Standard Penetration Tests (SPTs) were occasionally conducted in the borings as the boreholes were advanced into the overburden soils. The SPTs were performed in general accordance with ASTM D1586. In the SPT, a 2-in. O.D., 1-3/8 in. I.D. split-spoon sampler is driven 2 ft below the bottom of the borehole under the impact of a 140-lb weight free falling 30 in. The number of blows required to drive the sampler each successive 6 in. interval is recorded on the boring logs. The SPT N-value is the total number of hammer blows required to advance the sampler over a 12-in. interval counted from the sixth to the eighteenth inch the sampler was driven. In six of the test borings (HA17- B1, HA17-B4A, HA17-B5, HA17-B6, HA17-B7, and HA17-B8), 4 to 10 ft of bedrock was sampled using a 2.15-in. (NX-size) I.D. diamond-tipped core barrel.

The test boring logs are presented in Appendix B.

3.3.2 Landside – Crane Weight Test Area, Pier 32, and Pier 17 Stub

A subsurface exploration program was undertaken to provide data on soil and groundwater conditions on the landside of the proposed crane weight test area, proposed Pier 32, and the Pier 17 Stub. The program consisted of four test borings, designated HA19-B1 through HA19-B4; and two rock test probes, designated HA19-P1 and HA19-P2. The borings and test probes were drilled by Seaboard Drilling, Inc. of Chicopee, Massachusetts on 28 and 29 March 2019 under the full-time observation of Haley & Aldrich personnel.

The borings and test probes were drilled using a truck mounted drill rig. The borings where drilled to depths ranging from approximately 6.4 to 9.8 ft below the ground surface and were terminated at refusal on probable bedrock. The test probes were drilled to 27 and 57.5 ft below ground surface and were terminated upon refusal on probable bedrock. Soil samples were obtained using techniques and equipment in general accordance with the American Society for Testing and Materials (ASTM) Standard Specification D1586 - Standard Penetration Test (SPT). Test borings and probes were backfilled with soil cuttings and cold patch at the surface upon completion.

Locations of the test borings and probes are shown on the attached Figures 2A and 2B. Test boring reports are presented in Appendix B. Exploration locations were measured in the field by Haley & Aldrich by taping from known site features. Ground surface elevations at test boring elevations shown on the logs are approximate and were estimated using linear interpolation based on site topographic information. Locations and elevations of test borings should be considered approximate and accurate only to the degree implied by the method used.

4. Generalized Subsurface Conditions

4.1 PIER 32

The subsurface conditions encountered from the recent explorations at Pier 32 consist of the following geologic units presented in order of increasing depth below mudline: estuarine deposits, possible fill, glaciolacustrine deposits, glaciofluvial deposits, glacial till, and bedrock. Detailed soil descriptions are provided on the test boring logs in Appendix B.

Please note that the soil descriptions provided on the test boring logs and summarized below do not represent actual field conditions other than at the specific test boring locations. The actual conditions will vary from those described and shown herein.

Unit Approximate Range in Encountered Thickness

(ft)

Generalized Description

Estuarine Deposits 11.4 to 70 Very soft to stiff ORGANIC SOIL, ORGANIC SILT, SILT and elastic SILT with varying amounts of sand and gravel (OL/OH, OL, ML, MH) or loose silty SAND with varying amounts of silt (SM). With occasional shells and organic fibers.

(Encountered in all recent test borings.)

Possible Fill 20.6 Medium dense to dense poorly graded SAND and/or well graded SAND with varying amounts of silt and gravel (SP, SW) with occasional cobbles and shells.

(Encountered in boring HA17-B1.)

Glaciolacustrine Deposits 7.5 Very loose to very dense clayey SAND and/or poorly graded SAND with varying amounts of silt and gravel (SC, SP).

(Encountered in boring HA17-B1.)

Glaciofluvial Deposits 56.5 to 74 Very loose to very dense poorly graded SAND, well graded SAND, and silty SAND with varying amounts of silt, clay, and gravel (SP, SW, SP-SM, SM); well graded GRAVEL and poorly graded GRAVEL with varying amounts of silt and sand (GW, GP);

and/or hard SILT with varying amounts of sand and gravel (ML).

With frequent cobbles and occasional boulders.

(Encountered in all recent borings except HA17-B1)

Glacial Till 1.5 to 12 Very dense poorly graded SAND and silty SAND with varying amounts of silt and gravel (SP-SM, SP, SM) with occasional cobbles and boulders.

(Encountered in borings HA17-B1, HA17-B3, HA17-B5, HA17-B7, and possibly HA17-B8.)

Decomposed Bedrock 2 to 2.5 Decomposed bedrock based on drill action.

(Encountered in boring HA17-B5 and possibly HA17-B8.)

Bedrock was cored in borings HA17-B1, HA17-B4A, HA17-B5, HA17-B6, HA17-B7, and HA17-B8. The top of the bedrock surface at the boring locations where bedrock was cored ranged from approximately 46 to 143 ft below mudline (El. -69 to El. -185). In general, bedrock elevation slopes from the landside at approximate El. -21.8 to El. -185. Bedrock encountered at the site consisted of medium to very hard AMPHIBOLITE GNEISS or GRANTIC GNEISS.

Rock quality designation (RQD) is a common parameter that is used to help assess the competency of sampled bedrock. RQD is defined as the sum of pieces of recovered bedrock greater than 4 in. in length divided by the total length of the core run. RQD values for bedrock encountered at the site ranged between 29 and 100 percent, correlating to a Rock Mass Quality rating of poor to excellent.

The top of rock is steeply sloping over the eastern portion of the pier, as shown in Figure 3 (Top of Bedrock Contour Plan) and Figures 4 and 5 (Geologic Profiles). The rock slope in the eastern third of the pier ranges from 0.6H:1V (60 degrees) to 1.4H:1V (35 degrees). The top of rock slope in the remaining two-thirds of the pier footprint ranges from 8H:1V (7 degrees) to 50H:1V (1 degree). Steeper rock slopes may be present at the site.

4.2 CRANE WEIGHT TEST AREA

The subsurface conditions encountered from the recent explorations at the Crane Weight Test Area consist of the following geologic units presented in order of increasing depth below the ground surface:

bituminous concrete, possible fill and probable bedrock. Detailed soil descriptions are provided on the test boring logs in Appendix B.

Please note that the soil descriptions provided on the test boring logs and summarized below do not represent actual field conditions other than at the specific test boring locations. The actual conditions will vary from those described and shown herein.

Unit Approximate Range in Encountered Thickness

(ft)

Generalized Description

Bituminous Concrete 0.5 Multiple layers of bituminous concrete.

Possible Fill 5.9 to 9.3 Medium dense to very dense poorly graded SAND and/or well graded SAND with varying amounts of silt and gravel (SP, SW) with occasional cobbles.

The fill layer is likely associated backfilling of the quaywall. Borings were terminated at refusal on probable bedrock at depths ranging from 6.4 to 9.8 ft (El. -0.7 to -4.0) below the pavement surface.

Bedrock rock is anticipated to slope downward to the west.

4.3 PIER 17 STUB

Based on information from test probe HA19-P2 performed on the landside near the Pier 17 stub, probable bedrock from was encountered at 57.5 ft (El. -52.5). Bedrock rock is anticipated to slope downward to the west.

5. Geotechnical Laboratory Testing

Eight laboratory grain-size (ASTM D422) and eight moisture content analyses (ASTM D2216) were performed on soil samples recovered from the recent test borings. Unconfined compressive strength with elastic moduli and unit weight measurement (ASTM D7012D) was performed on eight rock core samples recovered from the recent test borings. A laboratory particle size analysis (ASTM D6913), Compaction test (ASTM D1557) and California Bearing Ratio Test (ASTM D1883) was performed on a composite sample of soil collected at HA19-B1 through HA19-B4 from depths of 1 to 5 ft. The laboratory testing was completed by GeoTesting Express, Inc. of Acton, Massachusetts.

The geotechnical laboratory test results are presented in Appendix C.

6. Geotechnical Design Recommendations

6.1 PIER 32

Based on the historical and recent subsurface information presented in our geotechnical report dated 25 June 2019, there are several potential geotechnical concerns at the site:

• Presence of steeply sloping bedrock surface (up to 60 degrees) at the eastern portion of the new pier. Based on subsurface information the bedrock surface steeply slopes downward to the north and west. Deep bedrock in other areas.

• Presence of many oversized components, including cobbles and boulders in the medium dense glacial soils. The presence of cobbles and boulders can cause difficult driving conditions for a driven pile foundation system and can potentially damage pile elements.

• Potential presence of obstructions in the near surface soils, particularly near the shoreline.

• Variable subsurface conditions, including relatively random encounters with oversized fragments.

• Pile dynamic testing results at Pier 31 showed highly variable results.

• High axial and lateral loads coupled with thick soft materials (Estuarine Deposits) leading to the potential for buckling of deep foundation elements.

• Maintaining pile alignment in area of shallow bedrock.

We reviewed and presented foundation support alternatives in our report dated 20 September 2019 and concluded that based on the anticipated subsurface conditions and potential concerns noted above, it is recommended that the deep foundations to support Pier 32 should consist of 36” diameter drilled shafts socketed into bedrock at locations where bedrock is steeply sloping (approximately the eastern third of the pier from Bents 1 through 10) and 36” diameter open-end steel pipe piles driven to capacity the top of bedrock, at locations where bedrock is relatively level (approximately the western two-thirds of the pier from Bents 11 through 24).

Design criteria and engineering considerations are provided below.

6.1.1 Drilled Shaft Foundation Design Criteria

Bedrock design parameters for ultimate and allowable unit side friction and end-bearing resistances for drilled shafts were calculated based on rock core information and laboratory testing obtained from recent test borings. Laboratory testing was performed on core samples and included rock compressive strength and intact elastic modulus.

The guidance used to assign the bedrock design parameters included references from AASHTO LRFD, FHWA Geotechnical Engineering Circular No. 10, and NCHRP Synthesis 360, which are generally accepted methods in the state of the practice. The evaluations assumed a 30-in. diameter rock socket, a 5,000 psi concrete compressive strength for the drilled shaft, and that the rock p-y curve is elastic-perfectly plastic with initial stiffnesses described by a horizontal coefficient of subgrade reaction and maximum described by a limit lateral pressure. Plots showing various core information and strength parameters are presented in the calculations for each core run from the borings are included in Appendix D.

Based on our evaluations we recommend the following design parameters:

Ultimate and Allowable Unit Resistances for Axial Design:

Case Ultimate Unit Side Friction Resistance

(ksf)

Ultimate Unit End-Bearing Resistance

(ksf)

Factor of Safety

Allowable Unit Side Friction Resistance

(ksf)

Allowable Unit- Ending Bearing

Resistance (ksf)

Static – Compression

28 201 3.0 (no load testing being performed)

9.3 67

The factor of safety noted in the table above are in accordance with Navy Guidance UFC-220-01 Geotechnical Engineering, DM 7.02 Foundations and Earth Structures, and/or the International Building Code 2018. If static axial load testing is performed, a factor of safety of 2 could be used for the static design. We understand that uplift resistance is not required.

The drilled shafts are typically situated 9 to 25 ft far apart center to center. In view of the embedment into the bedrock and the drilled shaft spacing, axial group effects will be small and were not considered.

Lateral load group effects should be taken into account in accordance with AASHTO LRFD Section 10.7.2.4.

We recommend using the following parameters for structural lateral loading assessments.

Lateral (p-y) Springs:

For a 30 in. diameter socket, use the following:

Effective Unit Weight of Bedrock = 100 pcf For rock lateral (P-y) curves, use k = 20,000 pci For rock lateral (P-y) curves, use a limit lateral pressure pL+tmax = 300 ksf

User input P-y curve for L-Pile:

Lateral Deflection, y (in.) Maximum Pressure, P (lb/in.)

0 0

0.104 62,500

3.0 (10% of socket diameter) 62,500

6.1.2 Driven Pipe Piles

Calculations were performed to evaluate the axial capacity of the 36-in. diameter pipe open-end pipe piles for support of the pier in the dense soils overlying the bedrock. These calculations were performed in accordance with NAVFAC DM 7.2 and UFC 3-220-01 Geotechnical Engineering. Since dynamic load tests were performed at the Pier 31 project, we used the Pile Driving Analyzer (PDA) data to evaluate pile capacity for proposed Pier 32 pier piles.

A series of PDA tests (10 tests) were conducted for Pier 31 pile installation. The results of dynamic pile load tests conducted at Pier 31 were reviewed for determination of side friction and end bearing in the soils for use at the Pier 32 site. Based on the PDA results, we recommend the following:

Side resistance in the Estuarine Deposits: 4 kips/ft (range: 3.6 to 8.4 kips/ft) Side resistance in the Glaciofluvial Deposits: 12 kips/ft (range: 11.4 to 30.1 kips) End bearing resistance in the Glacial Till deposits: 200 kips (range: 192 to 680 kips)

Based on these results we estimate that piles would need to be driven approximately 100 ft into the glacial soils to achieve the required ultimate resistance of 1,677.5 kips (design capacity of 671 kips, factor of safety of 2.5). We do not anticipate that the glacial deposits at Pier 32 will be 100 ft thick;

therefore, the piles will achieve the required capacity upon refusal on bedrock (see Figure 3, top of rock contour plan, for an estimate of expected pile tip elevations). The estimated pile tip elevations, assuming piles are driven approximately 1 ft into rock, will range from El. -175 to -185.

Our recommendations for pipe pile foundations are as follows:

In view of the presence of bedrock throughout the length of the pier, all of the piles should be driven to relative refusal (4 to 10 blows/in. using an appropriate pile hammer) on bedrock and designed for the structural capacity of the pile.

Piles should consist of 36-in. diameter, 0.5 in. wall thickness, 50 ksi steel with an allowable structural capacity is 695 kips, assuming the axial loads are supported by the steel only. The structural capacity calculation for the pier piles is presented in Appendix D. Piles should be fitted with an inside fit driving shoe.

Maximum pile settlement is estimated to be less than ¾ in. including settlement of the pile tip and elastic compression of the pile. Maximum differential settlement between the abutments and piers is expected to be less than ½ in. with settlement occurring during construction as deck loads are applied.

Lateral loading may be resisted by a combination of shear and bending at the tops of the piles, and the structural capacity of the upper portion of the pile. To add stiffness to the pile and reduce the chances of buckling, the designer may want to consider backfilling the upper portion of the pile with concrete.

We have assumed that the allowable axial capacity is limited to 33 percent of the yield strength of the steel (fy = 50ksi) to allow for additional bending stress in the pile due to lateral loads.

However, the actual capacities should be further checked for structural limitations such as buckling. The structural sections should be determined based on actual load conditions, corrosion considerations, and driving stresses. We have assumed a corrosion loss of 1/8-inch around the outside of piles. It is our experience that the inside of pipe piles do not readily corrode as there is little free-oxygen exchange that occurs once it is sealed.

The pile should be filled with concrete and reinforced to a minimum depth determined by Moffatt & Nichol.

Prior to driving piles, the piling contractor should be required to submit a predictive dynamic pile analysis (WEAP analysis) for the pile type, soil condition, and/or proposed piling hammer in order to determine the driving resistance required to achieve an ultimate capacity equal to or greater than the design capacity multiplied the safety factor. The WEAP analysis must show that the pile will not be overstressed at any point during driving. That analysis should be reviewed by the Geotechnical Engineer. Only after acceptance of the analysis, should the Contractor install piles. We recommend that 5 pier piles installed be dynamically tested utilizing a Pile Dynamic Analyzer (PDA) as manufactured by GRL, or equivalent. The PDA testing program should consist of piles during initial drive and restrike after a rest period for each pile hammer utilized and after major maintenance of pile hammer. Data from all tests should be further analyzed utilizing CAPWAP, or equivalent. CAPWAP analyses should be reviewed by the Geotechnical Engineer.

When tested as above, a safety factor of 2.5 for allowable compressive capacity is recommended.

6.1.3 Fender Piles

We understand the axial load on the fender piles is small. To achieve an allowable axial capacity of 10 kips (ultimate pile capacity 25 kips), we estimate that fender piles would need to be driven approximately 15 ft into the dense glacial soils, assuming the lower section consists of a steel HP10x42 pile. Estimated fender pile tip elevation is approximately El. -125. We recommend that a minimum of 3 fender piles be tested using the PDA, as presented above in Section 6.1.2.

The axial capacity calculation for the fender piles is presented in Appendix D.

6.1.4 Crane Weight Test Area

We understand that new drilled shafts are planned for a portion of the quay wall at the crane weight test area. Drilled shafts should be designed using the recommendations for Pier 32 noted above in Section 6.1.1.

6.1.4.1 Soil Parameters Landside of Quay Wall

In their unimproved states, it is recommended that the following properties of subsurface materials be used for design purposes:

Stratum Total Unit Weight

(pcf)

Effective Unit Weight (below 5 ft)

(pcf)

Friction Angle (deg) p-y modulus (pci)

Sand and Gravel (Probable Fill) 120 56 34 125

6.1.5 Equipment Platform Foundations

This section of the report provides recommendations for design of equipment platform foundations for the proposed Backflow Preventor and Electrical Switchgear located on the landside of Pier 32. Based on the Pier 32 landside probes, and our understanding of the site geology; the soil conditions are favorable for construction of conventional reinforced concrete spread footing foundations (footings). We understand that the self-weight of the structures is adequate to resist the uplift loading from the design flood. Foundations should be designed and constructed in accordance with the applicable portions of the Connecticut State Building Code and Unified Facilities Criteria (UFC), latest editions, and the recommendations provided in the following sections of this report.

We recommend the equipment platforms be supported on footings designed in accordance with the following:

• Design spread footings to be founded on the undisturbed Glaciofluvial Deposits; or, if existing fill is encountered at the design bearing elevation, on Granular Fill placed following removal of the existing fill to the top of the undisturbed Glaciofluvial Deposits. The existing fill is not suitable for foundation support.

• Size footings using an allowable bearing pressure of 3 kips per square foot (ksf). The allowable bearing pressure may be increased by 1/3 for transient loading conditions.

• For footings less than 3 ft in least lateral dimension, design for an allowable bearing pressure in ksf equal to B, where B equals the footing width in feet.

• Design for a minimum footing width of 18 in.

• If unsuitable soils (e.g., existing fill) are encountered at the footing bearing elevation, either:

a) lower the footing to the suitable bearing material, or

b) maintain the footing at the design bearing elevation and replace unsuitable materials within the Zone of Influence (ZOI) with Granular Fill placed in accordance with the recommendations herein.

• Design footings to bear a minimum of 3.5 ft below proposed grades exposed to freezing temperatures for frost protection.

• For the recommended allowable bearing pressure, we estimate total settlement of foundation elements will be less than 1 in., and differential settlement between adjacent foundation elements will be less than ½ in. The majority of these settlements will typically occur as structure dead load is applied during construction.

6.2 LATERAL RESISTANCE

Haley & Aldrich, Inc. conducted preliminary lateral resistance evaluation using the software program LPile by Ensoft, Inc. using preliminary geotechnical information.

We have assumed a fixed head condition for the pier piles. The results of the lateral load evaluations for the pier piles are summarized in Appendix D in a curve of lateral load applied to the top of the pile vs lateral deflection at the top of the pile.

The fender piles are tied to the pier structure at the top and therefore a lateral load evaluation was not performed.

We understand that final lateral resistance of the drilled shafts and driven piles will be evaluated by Moffatt & Nichol.

6.3 SITE SPECIFIC SEISMIC RESPONSE

Site-specific seismic response analyses were performed for the site according to the following guidelines:

1. EM1110-2-6050 “Response Spectra and Seismic Analysis for Concrete Hydraulic Structures”, USACE, 6/30/1999

2. EM1110-2-1806 “Earthquake Design and Evaluations for Civil Works Projects” USACE, 5/31/2016

3. EM1110-2-6053 “Earthquake Design and Evaluation of Concrete Hydraulic Structures”, USACE, 5/1/2007

4. ASCE 7-10, “Minimum Design Loads for Buildings and Other Structures”

Two seismic hazard levels were analyzed corresponding to earthquake return periods of 475 years and 2,475 years. One target response spectrum (spectral acceleration vs period) was developed for each of the two return periods using the above guidelines and the United States Geological Survey (USGS) Earthquake Hazards Program website. Seven rock motions (i.e., time histories of acceleration) were then selected and scaled to each of the two target response spectra, these scaled motions were used as the input rock motions in the site-response analyses.

Site subsurface conditions were represented by shear wave velocity (Vs) profiles of the soil and bedrock at the boring locations. Shear wave velocity for the overburden soils was estimated using published correlations between Vs and SPT-N. Depth to bedrock is estimated to vary along the proposed pier from about 10 ft close to shore to about 140 ft at the pier end. One soil column was modeled representing the deep rock condition. In order to account for uncertainty, the soil Vs was assumed to vary by 25% above and below the estimated values resulting in three Vs profiles for the single soil column. The bedrock Vs was assumed to be 5,000 ft/s (i.e., Site Class A).

Site response analysis was performed using DEEPSOIL, a one-dimensional wave propagation software program created by the University of Illinois at Urbana-Champaign. For the model soil column, the response spectrum at mudline was calculated for each Vs profile and input rock motion combination, resulting in 21 calculated response spectra per return period. The mean of the 21 spectral acceleration values were calculated at each period and were used to construct the mean or average spectrum at mudline. The response spectra of rock motions and mean spectra at mudline for the 475-year and 2,475-year return periods are provide in Appendix D.

6.4 SEISMIC SITE CLASS

We made an evaluation of the seismic Site Class based on the subsurface conditions encountered in the recent explorations. Due to the presence and thickness of soft organic silt material at a number of the exploration locations, we recommend a seismic Site Class F based on the guidance provided in IBC 2015 and ASCE 7-10. The seismic site class calculation is presented in Appendix D.

6.5 LIQUEFACTION

The liquefaction susceptibility of the granular soils at the site was determined by calculating the ratio between the cyclic resistance ratio (CRR) of the in-situ soils at each sample location and equivalent uniform cyclic stress ratio (CSR) imposed by the design earthquake. This ratio was modified using a magnitude scaling factor (MSF) to account for earthquake magnitudes different from M 7.5 to obtain the factor of safety against liquefaction. Liquefaction of the in-situ granular soils will occur when the factor of safety is less than 1.0.

Based on the results of the simplified liquefaction evaluation for this site, it is our opinion that the site soils are not liquefaction susceptible. Two samples had a factor of safety against liquefaction of less than 1.0. In our opinion, this result does not indicate the presence of a continuous liquefiable zone of material. The factor of safety in the remaining samples from all of the borings were greater than 1.0.

Plots of factor of safety against liquefaction are provided in Appendix D.

7. Geotechnical Construction Consideration

7.1 GENERAL

The primary purpose of this section is to provide comments related to earthwork, excavation, foundation construction, and other geotechnical engineering aspects of the proposed construction. It will provide a basis for the preparation of contract drawings and specifications and performing construction observation. Prospective contractors for this project should evaluate potential construction issues on the basis of their knowledge and experience with similar sites and subsurface conditions in the area of the base, taking into account their own proposed construction methods and procedures.

7.2 EARTHWORK

Shallow excavations are expected to penetrate the Fill layer for the purpose of constructing footings, slabs, and pavements. Fill materials primarily consists of heterogeneous deleterious constituents and are not recommended for re-use on site for any purpose other than non-structural general filling. We further understand that there may be environmentally-driven reasons that would take precedence over any geotechnical Fill handling recommendations.

Excavations for the proposed equipment platforms are anticipated to extend to depths of 4 ft.

Foundations for former site buildings and existing utilities should be anticipated and will also require removal during excavation.

Support of utilities (existing to remain in service or proposed), and nearby facilities should be reviewed by the earthwork contractor based on its specific excavation plan and by the general contractor/construction manager relative to its construction staging and traffic control plan.

7.2.1 Mass Excavation

The proposed landside structures will require excavation through Fill and Glaciofluvial Deposits. We anticipate that conventional earth moving equipment can be used for mass earthwork operations at the site.

Foundations of former structures and other substructure elements, historic utilities, rubble, construction debris, former seawalls, and other materials are likely to be encountered. Hoe-ramming, hot-work, or other techniques may be needed to remove below-grade obstructions.

Where space permits, open cut soil slopes inclined no steeper than 1.5H:1V. Some sloughing and raveling should be anticipated on temporary earth slopes constructed at this inclination. Excavation and sloping should be conducted in accordance with OSHA and other applicable regulations.

7.2.2 Preparation and Protection of Bearing Surfaces

Bearing surfaces should be prepared in accordance with the following recommendations:

During excavation and foundation construction operations, precautions should be taken to prevent disturbance to the bearing soils, including by construction activities and the presence of water.

The exposed subgrade soils must be examined in the field by the Contracting Officer or their representative to observe their character, integrity, and condition. It may be necessary to over-excavate and replace weak, disturbed, or otherwise unacceptable soils. Surface water should not be allowed to collect on exposed soil bearing surfaces.

Over-excavation of disturbed or unsuitable soils below design foundation bearing grade should be backfilled with lean concrete or suitable fill.

Soil bearing surfaces below completed foundations must be protected against freezing before and after foundation construction. If construction is performed during freezing weather, footings should be backfilled to a sufficient depth (up to 4 ft) as soon as possible after they are constructed. Alternately, insulating blankets, heating or other means may be used for protection against freezing.

A crushed stone layer should be placed over exposed subgrades to provide protection until foundation concrete is placed. A 6-oz/SY non-woven geotextile should fully encapsulate (wrapped around bottom, sides, and top with 1-ft overlap) the crushed stone layer to prevent migration of subgrade soils into the crushed stone. Alternately a lean concrete “mud mat” may be placed on prepared subgrades.

Excavations below the groundwater table are generally not anticipated, but rainwater, tidal fluctuations, and runoff may enter excavations. High tides may influence groundwater level.

The contractor should prevent the flow of surface water onto bearing surfaces at all times. And water that enters excavations should be dewatered in a manner that avoids pumping of fines and retains the integrity of natural or prepared bearing surfaces.

Smooth edged buckets or hand excavation should be used as necessary to prevent the disturbance of bearing soils. Use of non-smooth-edged buckets to excavate soils at final subgrade will disturb subgrades and should not be allowed. Areas of soft, unstable or disturbed soils will need to be over-excavated to firm and stable soils and replaced with suitable fill.

7.2.3 BACKFILLING

We recommend that suitable fill similar to CTDOT M.05.01 be used for backfill around footings and beneath crane weight storage slabs-on-grade. Backfill outside of structures should also consist of suitable common fill except for special filling required for pavements, landscaping, or other site improvements.

Placement of fill should not be conducted when air temperatures are low enough (approximately 30 degrees F or below) to cause freezing of the moisture in the fill during or before placement. Fill materials should not be placed on water, snow, ice or frozen soil. Frozen soil or soil containing frozen materials should not be used as compacted fill.

7.3 DRILLED SHAFTS

The means and methods of the installation of drilled shafts are the responsibility of the Contractor. The performance of the drilled shafts is highly dependent on the experience and means and methods of the drilled shaft Contractor. Consideration should be given to the following during drilled shaft construction:

Running sands may be encountered, especially in the Glaciofluvial Deposits as drilled shafts are advanced. Temporary casing and possibly drilling fluid may be required for keeping drill holes open.

Contractor shall understand bedrock conditions and drilling on steeply sloping bedrock.

Contractor should be experienced with reverse-circulation drilling; down-hole-hammers; rock augers; core barrels are all methods of dealing with the sockets.

Boulders may be encountered within the soil, especially through the Glaciofluvial Deposits and possible at the bedrock interface, during drilled shaft construction.

Near surface obstructions may be encountered during drilled shaft construction particularly when drilling near the head of the pier.

Haley & Aldrich has assisted Moffatt & Nichol in developing special provisions for drilled shaft installation and inspection. The special provisions include obstruction removal, placement of concrete, drilled shaft construction methodology, construction tolerances, bottom cleaning, reinforcement placement, construction sequence, inspection/testing, and prequalification of Contractors.

Drilled shafts should be constructed with steel access tubes to allow for crosshole sonic logging (CSL) and thermal wires to allow for Thermal Integrity Profiling (TIP). CSL and TIP testing should be performed at the drilled shafts.

7.4 PILE DRIVING

In our experience, static load testing of piles installed for over-water structures can be costly and time consuming. Therefore, given the high allowable capacities, performing a program of dynamic load testing of production piles should be performed.

Prior to driving piles, the piling contractor should be required to submit a predictive dynamic pile analysis (WEAP analysis) for each pile type (pile and H-Pile), soil condition, and/or proposed piling hammer in order to determine the driving resistance required to achieve an ultimate capacity equal to or greater than the design capacity multiplied the safety factor. The WEAP analysis must show that the pile will not be overstressed at any point during driving. That analysis should be reviewed by the Contracting Office or their representative. Only after acceptance of the analysis, should the Contractor install piles.

We recommend that the hammer energy should be determined based upon the results of a Wave Equation Analysis performed by the contractor based upon his proposed driving equipment and configuration.

The Contractor will be required to confirm the minimum required ultimate pile resistances of pier piles and fender piles in the field using dynamic testing methods. We recommend that Contractor perform dynamic pile load tests with 24-hour (minimum) restrike tests on approximately 5 pipe piles and 3

Fender Piles to evaluate hammer system efficiencies, driving stresses in the pile, and the ultimate resistance of the piles. We recommend that the dynamic pile load tests be completed prior to production pile driving. We also recommend that CAPWAP analysis be performed on each pile installed during the dynamic test program. CAPWAP analyses should be reviewed by the Contracting Officer or their representative.

Cobbles and boulders are present in the glacial soils at the site. The presence of cobbles and boulders can cause difficult driving conditions for a driven pile foundation system and can potentially damage pile elements. All piles (pipe and H-piles) should be outfitted with a driving point to protect the piles during hard driving and embedment into the bedrock surface. The pile specifications should require the pile driving contractor to be prepared to deal with obstructions and clearly delineate procedures and criteria for overcoming obstructions.

FIGURES

APPROXIMATE SCALE: 1 IN = 2000 FT

OCTOBER 2019 FIGURE 1

PROJECT LOCUS

P-898 REPLACE SSN BERTHING PIER 32

NAVAL SUBMARINE BASE NEW LONDON

GROTON, CONNECTICUT

-0

_1

_L O

C U

S.

PD

F

SITE COORDINATES: 41°23'52"N, 72°5'39"WMAP SOURCE: ESRI

Pdunaj Oval

Pdunaj Oval

Pdunaj Oval

Pdunaj Oval

Pdunaj Callout Crane Weight Test Area

Pdunaj Callout Pier 32

Pdunaj Callout Pier 17

Pdunaj Callout Pier 10

0 3

0 3

HA17-B1

HA17-B2

HA17-B3

HA17-B4\B4A

HA17-B5

HA17-B7

HA17-B8

HA17-B6

HA17-P1

HA17-P2

HA17-P3

HA19-P1

HA19-P2

LEGEND

DESIGNATION AND APPROXIMATE LOCATION OF TEST PROBE

PERFORMED BY SEABOARD DRILLING, INC. ON 29 MARCH 2019.

DESIGNATION AND APPROXIMATE LOCATION OF TEST BORING

PERFORMED BY GEOLOGIC EARTH EXPLORATION, INC.

BETWEEN 12 APRIL AND 15 SEPTEMBER 2017.

DESIGNATION AND APPROXIMATE LOCATION OF PROBE

PERFORMED BY GEOLOGIC EARTH EXPLORATION, INC.

BETWEEN 18 AND 26 SEPTEMBER 2017.

LOCATION AND ORIENTATION OF SUBSURFACE PROFILE

0 100 200

SCALE IN FEET

O

P I E

R

C

A D

S E

L P

D

W G

P E

R E

Z

M

E J I A

K

A T

R I N

A F

I G

U R

E

A

P

M L a y o u t

P r i n t e d

FIGURE 2A

P-898 REPLACE SSN BERTHING PIER 32

NAVAL SUBMARINE BASE NEW LONDON

GROTON, CONNECTICUT

SITE AND SUBSURFACE

EXPLORATION LOCATION PLAN

SCALE: AS SHOWN

OCTOBER 2019

HA17-B1

NOTES

1. PROPOSED PIER LAYOUT TAKEN FROM FIGURE NO. S-1

PROVIDED BY MOFFATT & NICHOL ON 30 MARCH 2017.

2. "AS-DRILLED" EXPLORATION LOCATIONS WERE

DETERMINED BY HALEY & ALDRICH, INC. USING GPS

SURVEY EQUIPMENT AND TAPING FROM EXISTING SITE

FEATURES.

3. SUBSURFACE EXPLORATIONS WERE MONITORED BY

HALEY & ALDRICH, INC. PERSONNEL.

HA17-P1

A B

HA19-P1

A

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