1614696spc09of19_APP-B1.pdf

APPENDIX - B

(PART-1)

GEOTECHNICAL

ENGINEERING REPORT

FY21 MCON PROJECT P-095

REPLACE SUBMARINE PIER 3

NAVAL STATION NORFOLK, NORFOLK, VA

eProjects Work Order No. 1614696 A-E Contract No. N40085-18-D-1100

Delivery Order N40085-19-F-4195

REPORT OF

SUBSURFACE

EXPLORATION

AND

GEOTECHNICAL

ENGINEERING

SERVICES

NAVSTA Norfolk- P-095 Replace Submarine Pier 3-Full D-B-B

Naval Station Norfolk, Norfolk, Virginia

G E T Project No: VB19-314G

December 14, 2020

PREPARED FOR:

5465 Greenwich Road · Virginia Beach, VA 23462 Phone: (757)-518-1703 www.getsolutionsinc.com

2/01/2020

11/18/2020

12/13/2020

12/14/2020

5465 Greenwich Road · Virginia Beach, VA 23462 · Phone: (757)-518-1703 · Fax: (757)-518-1704 info@getsolutionsinc.com

December 14, 2020

TO: Moffatt & Nichol 101 W Main St. #800 Norfolk, VA 23510

Attn: Mr. Chris LaPlatney, PE, CEM

RE: Report of Subsurface Exploration and Geotechnical Engineering Services NAVSTA Norfolk-P-095 Replace Submarine Pier 3-Full D-B-B Naval Station Norfolk, Norfolk, Virginia G E T Report No.: VB19-314G

Dear Mr. LaPlatney:

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

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

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

Respectfully Submitted, G E T Solutions, Inc.

Maria E. Murdock, P.E.

Senior Project Engineer VA Reg. # 039988

Bruce R. Spiro, P.E. D. Mark Scholefield, P.E.

Principal Engineer Principal Engineer VA Reg. # 015791 VA Reg. # 033932 Copies: (1) Client

TABLE OF CONTENTS

NAVSTA Norfolk-P-095 Replace Submarine Pier 3-Full D-B-B Naval Station Norfolk, Norfolk, Virginia GET Report No.: VB19-314G

1.0 PROJECT INFORMATION

1.1 Project Authorization

1.2 Project Site Location and Description

1.3 Purpose and Scope of Services

2.0 FIELD AND LABORATORY PROCEDURES

2.1 Field Exploration

2.2 Field and Laboratory Testing

2.2.1 Soil Classification and Index Testing

2.2.2 Bulk Soil Sample Testing

2.2.3 Environmental Testing

2.2.4 Compression Testing

3.0 SITE AND SUBSURFACE CONDITIONS

3.1 Site Geology

3.2 Recent Land Reclamation and Site Development

3.3 Existing Pavement Section Description

3.4 Subsurface Soil Conditions

3.5 Groundwater Discussion

4.0 EVALUATIONS AND RECOMMENDATIONS

4.1 Clearing and Grading

4.2 Subgrade Preparation

4.3 Select Fill and Placement

4.4 Suitability of On-site Soils

4.5 Guard Booth, Gatehouse and Canopy

4.5.1 Foundation Excavations- Guard Booth, Gatehouse and Canopy

4.5.2 Shallow Foundation Design Recommendations- Gatehouse and Canopy

4.5.3 Settlements- Gatehouse and Canopy

4.5.4 Slab-on-Grade Design- Gatehouse and Canopy

4.5.5 Guard Booth- Mat Foundation Recommendations

4.6 Pavement Design Recommendations

4.7 Combi-walls CEP-172 and CEP-102

4.7.1 Soil Parameters fore Bulkhead

4.7.2 Earth Pressures from Earthquakes

4.8 Pile Design and Testing Recommendations

4.8.1 Axial Compression Capacity Recommendations- Berthing Pier 3

4.8.2 Lateral Pile Capacity Recommendations- Berthing Pier 3

4.8.3 Axial Compression Capacity Recommendations- CEP-102 Wharf Section

4.8.4 Axial Compression Capacity Recommendations- CEP-176 Wharf Section

4.8.5 Axial Compression Capacity Recommendations- Utility Bedding

4.8.6 Pile Drivability Considerations

4.8.7 Negative Skin Friction Discussion

4.8.8 Test Piles

4.8.9 Dynamic Testing

4.8.10 Establishing Pile Driving Criteria

4.8.11 Allowable Driving Stresses

4.8.12 Hammer Types and Energies

4.8.13 Driven Pile Installation Monitoring

4.8.14 Pile Group Settlement

4.9 Buried Utility Manholes, Vaults, Inlets and Utility Lines

TABLE OF CONTENTS

Naval Station Norfolk, Norfolk, Virginia GET Report No.: VB19-314G

4.9.1 Beding Recommendations for Utility Lines

4.9.2 Manholes, Vaults and Inlets Construction Recommendations

4.10 Site Classification

4.11 Liquefaction Potential

5.0 CONSTRUCTION CONSIDERATIONS

5.1 Anticipated Excavation Characteristics

5.2 Excavation Stability

5.3 Dewatering

6.0 REPORT LIMITATIONS

APPENDIX I SITE VICINITY PLAN

APPENDIX II BORING LOCATION PLAN

APPENDIX III CLASSIFICATION SYSTEM FOR SOIL EXPLORATION

APPENDIX IV SUMMARY OF LABORATORY CLASSIFICATION RESULTS

APPENDIX V BORING LOGS

APPENDIX VI GENERALIZED SOIL PROFILES

APPENDIX VII CBR TEST RESULTS

APPENDIX VIII ENVIRONMENTAL TEST RESULTS

APPENDIX IX SHELBY TUBE CLASSIFICATIONS

APPENDIX X TRIAXIAL TEST RESULTS

APPENDIX XI HISTORIC LAND USE

APPENDIX XII PAVEMENT SECTION COMPOSITION AND THICKNESS

APPENDIX XIII CPTU DATA

APPENDIX XIV CALCULATIONS GEOTECHNICAL EVALUATIONS

APPENDIX XV SOIL PARAMETERS BULKHEADS

APPENDIX XVI L-PILE/LATERAL PILE CAPACITIES

APPENDIX XVII SEISMIC SITE CLASSIFICATION

APPENDIX XVIII LIQUEFACTION ANALYSIS

APPENDIX XIX HISTORIC GEOTECHNICAL INFORMATION

Report of Subsurface Exploration and Geotechnical Engineering Services December 14, 2020

Naval Station Norfolk, Norfolk, Virginia G E T Report No.: VB19-314G

1.0 PROJECT INFORMATION

1.1 Project Authorization

G E T Solutions, Inc. has completed our subsurface exploration and geotechnical engineering services for the proposed NAVSTA Norfolk-P-095 Replace Submarine Pier 3-Full D-B-B project located at Naval Station Norfolk in Norfolk, Virginia. The geotechnical engineering services were conducted in general accordance with the scope presented in G E T Proposal No. PVB19-464G revised on October 31, 2019 and SAES dated November 4, 2019. Authorization to proceed with our services was received from the client in the form of an executed Master Services Subcontract Agreement.

1.2 Project Site Location and Description

The project site is located at Pier 3 and its vicinity within Naval Station Norfolk in Norfolk, Virginia. The proposed construction will consist of building a replacement Pier 3 relocated to the north of its existing location perpendicular to and attached to the face of bulkhead CEP-102, to align with a new bulkhead in front of the existing CEP-176 bulkhead. Existing site grades along the existing Pier 3, bulkhead CEP-176 and CEP- 102 range from roughly 6 to 9 feet NAVD88. All elevations throughout this report are based on NAVD88. Structural loading information was provided by the design team.

The proposed construction will include the following structures:

1. Berthing Pier 3 which will be pile supported with a concrete deck, ±1,330 feet in length by ±85 feet in width. The proposed Pier 3 design elevation is expected to be 12.5 feet NAVD88.

2. The north facing bulkhead, Bulkhead CEP-176, will be constructed as a combi-wall consisting of steel sheet piles and pipe piles. Design grade will be raised 5 feet from existing grades inland of the bulkhead. A ±100-foot wide relieving platform will support the fill to attain design grade. Two ramps, one on the eastern end and the second one on the western end of the relieving platform, will be constructed to transition from existing grades to the design grade of the platform. The relieving platform and ramps will be supported on steel HP-piles.

3. A new bulkhead designated as CEP-102, with a pile supported wharf in front, will consist of a combi-wall (steel sheet piles and pipe piles) and steel sheet piles.

The wharf will be ±670 feet in length and ±30 feet in width. The design elevation of the wharf will remain the same as existing grades.

4. A ±330 feet long by ±50 feet wide Utility Services Building with finished grades 2 feet above existing grade.

5. A Gatehouse with an expected floor loading of 200 psf and wall loads of 3 klf.

6. A Gatehouse canopy, which is expected to be supported by spread footings loaded with 15 kips in compression.

Naval Station Norfolk, Norfolk, Virginia G E T Report No.: VB19-314G

7. A guard booth with uniform loads on the order of 125 psf.

Dredging at the proposed Pier 3 and in the Pier 3T Basin will be performed during to the project construction. The recommendations provided in this report are based on the Maximum Design Depths or dredge depths listed below.

· Pier 3: Maximum Design Depth (future dredging elevation) is -47.64 feet

NAVD88.

· CEP 176: Maximum Design Depth is -40.64 feet NAVD88.

· CEP 102: project dredge elevation at the interface between the proposed combi-wall and water is -22.64 feet NAVD88; the Maximum Design Depth at the waterside of the wharf is -40.64 feet NAVD88.

A plan depicting the proposed construction is provided in Figure 1. A site vicinity plan based on the 7.5 Minute Series Norfolk North Quadrangle (2016) is provided in Appendix I.

Figure 1: Proposed Construction

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

Naval Station Norfolk, Norfolk, Virginia G E T Report No.: VB19-314G

1.3 Purpose and Scope of Services

The purpose of this study was to provide evaluations and recommendations based on historic geotechnical information in the vicinity of the project and the current geotechnical exploration. A preliminary geotechnical report of the proposed construction was submitted as Conceptual/Preliminary Report of Subsurface Exploration and Geotechnical Engineering Services, VB18-344G, dated July 2, 2019 (Appendix XIX); this conceptual report includes the available historic information in the vicinity of the project site provided by the client (subsurface data, pile driving and load testing records, and selected record drawings). Additionally, historical topographic and geologic maps of the site were reviewed. The purpose of this report is to provide engineering assessments for the following items:

· Environmental laboratory results of soils recovered from borings within the proposed dredge areas and depths.

· Shallow foundation recommendations (Guard Booth, Gatehouse and Canopy).

· Pavement subgrade preparation and pavement section recommendations.

· Estimated soil parameters of the soils behind and in front of the proposed combi-walls (CEP-102 and CEP-176).

· Pile capacity recommendations for support of proposed Pier 3, wharf piles and king piles at CEP-102 and CEP-176, and Utility Services Building.

· Lateral pile capacity considerations for the support of proposed Pier 3.

· General pile driving recommendations.

· Test pile program recommendations.

· Utility trench bedding/backfill recommendations.

· Buried utility structure recommendations.

· Seismic site classification(s).

· Liquefaction potential/analysis.

· Provide interpreted Cone Penetration Test (CPTu) data (soil type, peak friction angle, undrained strength, relative density, etc.).

2.0 FIELD AND LABORATORY PROCEDURES

2.1 Field Exploration

The field exploration program was coordinated with the Port Operations Manager to minimize the impact on port operations. G E T Solutions, Inc. met with the Port Operations Manager and reviewed security requirements and established a schedule for performing the work.

Naval Station Norfolk, Norfolk, Virginia G E T Report No.: VB19-314G

G E T Solutions, Inc. notified the client and applicable Base personnel of all field activities prior to mobilizing to the site. Additionally, clearance from VA811 was obtained prior to drilling and a private subsurface utility locator was subcontracted to verify the presence of existing buried utility lines in the vicinity of the proposed exploration locations. To explore the general subsurface soil types, the exploration program listed in Table I (on the following page) was performed. The test locations were verified with the client prior to the field activities. Land tests were backfilled with a cement-bentonite grout mix and the upper 6 inches were patched with quick setting sack mix concrete. Soil cuttings, surplus soils samples and decontamination fluids mixed with grout were returned to the point of collection. A properly trained field geotechnical engineer or geologist was on-site during drilling to log and classify the soil samples in the field.

Standard Penetration Tests (SPT) were performed in the field in general accordance with ASTM D1586. The tests were performed continuously from the existing ground surface (at the land SPT borings) or from mudline (at the water SPT borings) to a depth of 12 feet, and at 5-foot intervals thereafter starting at a depth of 13 feet. The SPT soil samples were obtained with a standard 1.4” I.D., 2” O.D., 30” long split-spoon sampler.

The sampler was driven with blows of a 140 lb. hammer falling 30 inches, using an automatic hammer. The number of blows required to drive the sampler each 6-inch increment of penetration was recorded and is shown on the boring logs. The sum of the second and third penetration increments is termed the SPT N-value (uncorrected for automatic hammer and overburden pressure). A representative portion of each disturbed split-spoon sample was collected with each SPT, placed in a glass jar, sealed, labeled, and returned to our laboratory for review.

Four-inch diameter cores were drilled at the location of the landside tests to determine the thickness and composition of the pavement section. Additionally, thin-walled Shelby tubes were extracted from the CLAY stratum from some of the boreholes. The Shelby tube samples were obtained hydraulically pressing a 3-inch outside diameter Shelby tube into the targeted soils (see Section 2.2.4 for details). The tubes were sealed in general accordance with ASTM standards and returned to G E T Solutions, Inc.’s Virginia Beach laboratory for extraction, classification, and compression testing.

The water SPT borings and CPTu probes were drilled from a 120-foot long, 50-foot wide, and 8-foot deep barge with a 150-ton crawler crane. The barge was mobilized from Crofton’s yard (16 Harper Road, Portsmouth, Virginia) to the job site with the aid of a tugboat.

The CPTu and SCPTu probes and soundings on land were performed with a 25-ton Truck Rig; the CPTu probes on water were performed from a 14-ton Portable Hydraulic Ramset CPTu welded to the deck of the barge. The SPT drill rig was on board the barge during the CPTu probes.

Naval Station Norfolk, Norfolk, Virginia G E T Report No.: VB19-314G

The locations of the SPT borings, CPTu probes and SCPTu soundings were staked in the field by a representative of G E T Solutions, Inc. using a hand-held Global Positioning System (GPS) device. The approximate test locations are shown on the attached “Boring Location Plan” (Appendix II), which was developed based on a site plan provided by the client.

Each test location was recorded in WGS 84 latitude and longitude Global Positioning System (GPS) coordinate system with a Garmin 48S device. The coordinates are identified in the boring logs in State Plane northing and easting US Survey feet.

Table I-Soil Boring Schedule Boring ID Type Land or Water Structure

2019GETWC-1 CPTu Water Pier 3 2019GETWC-2 CPTu Water Pier 3 2019GETWB-3 SPT Water Pier 3 2019GETWC-4 CPTu Water Pier 3 2019GETWC-5 CPTu Water Pier 3 2019GETWB-6 SPT Water Pier 3 2019GETB-7 SPT Land CEP-176 2019GETC-8 SCPTu Land CEP-176 2019GETC-9 CPTu Land CEP-176

2019GETC-10 CPTu Land CEP-176 2019GETB-11 SPT Land CEP-102 2019GETC-12 CPTu Land Utility Service Building 2019GETB-13 SPT Land Utility Service Building

2019GETWC-14 CPTu Water CEP-102 2019GETC-15 SCPTu Land CEP-102 2019GETB-15 SPT Land CEP-102

2019GETWB-16 SPT Water CEP-102 2019GETB-17 SPT Land CBR 2019GETB-18 SPT Land CBR 2019GETB-19 SPT Land CBR 2019GETB-20 SPT Land CBR 2019GETB-21 SPT Land CBR 2019GETB-22 SPT Land CBR 2019GETB-23 SPT Land CEP-102 2019GETC-24 CPTu Land CEP-176

2019GETWC-25 CPTu Water CEP-176 2019GETWC-26 CPTu Water Pier 3 2019GETWC-27 CPTu Water Pier 3 2019GETWB-28 SPT Water Pier 3T 2019GETWB-29 SPT Water Pier 3T

Naval Station Norfolk, Norfolk, Virginia G E T Report No.: VB19-314G

Listed below are a few notes about Table I.

· CPTu: Cone Penetrometer Test.

· SPT: Standard Penetration Test.

· SCPTu: Seismic Cone Penetration Test.

· 2019GETC-15 encountered refusal at a depth of 92.2 feet below grade.

· The water CPTu tests encountered refusal prior to the targeted penetration depth.

Penetration refusal appears to have occurred within the Yorktown Formation due to the relative density of these SANDs.

· 2019GETB-15 was offset 5 feet from 2019GETC-15. The purpose of the boring was to explore the soils beneath the termination depth of 2019GETCPT-15.

2.2 Field and Laboratory Testing

Soil testing provided by G E T Solutions, Inc. was performed in accordance with American Society for Testing and Materials (ASTM) standards. All soils and materials tests were performed in our AASHTO re:source (formally AMRL) and US Army Corps of Engineers certified Virginia Beach laboratory.

2.2.1 Soil Classification and Index Testing

Representative portions of all soil samples collected during drilling operations were labeled, preserved and transferred to our laboratory in accordance with ASTM D4220 for classification and analysis. Soil descriptions on the boring logs are provided using visual-manual methods in general accordance with ASTM D2488 using the Unified Soil Classification System (USCS). Soil samples that were selected for index testing were classified in general accordance with ASTM D2487. It should be noted that some variation can be expected between samples classified using the visual-manual procedure (ASTM D2488) and the USCS (ASTM D2487). A summary of the soil classification system is provided in Appendix III.

Representative bulk and split-spoon soil samples were selected and subjected to natural moisture, #200 sieve wash, and Atterberg Limits testing in order to corroborate the visual classification. These test results are presented in Appendix IV and on the soil test boring logs provided in Appendix V. Generalized subsurface soil profiles are provided in Appendix VI.

Naval Station Norfolk, Norfolk, Virginia G E T Report No.: VB19-314G

2.2.2 Bulk Soil Sample Testing

Four (4) bulk soil samples were returned to our AASHTO re:source certified Virginia Beach laboratory and subjected to Standard Proctor and CBR testing. The stress-strain curve was plotted for each specimen. If necessary, the stress-strain curves were corrected by adjusting the location of the origin for concave shaped curves.

Subsequently, the CBR values were selected at 0.1-inch penetration using the corrected load values. A summary of the CBR test results is presented in Table II and the Proctor curves, Particle Size Distribution Reports, and the CBR curves are provided in Appendix VII.

Table II – CBR Test Results Boring

ID

Depth Below

Grade (ft) USCS wN

Passing

#200 Sieve

Atterberg Limits

(LL/PL/PI)

Max. Dry Density

(pcf)

Optimum Moisture

CBR

Value

Swell

2019GET

B-7 1-5 SM 11 12.2 Non-

Plastic 111.8 13.2 15.0 0

2019GET

B-11 1-5 SC 9 24.0 20/12/8 122.0 9.7 11.6 0.1

2019GET

B-13 1-5 SP-SM 5 9.6 Non-

Plastic 110.2 11.7 19.1 0

2019GET

B-18 1-5 SM 4 13.6 Non-

Plastic 116.4 9.5 21.7 0

Note(s): (1) wN – Natural Moisture Content

2.2.3 Environmental Testing

In accordance with the Scope of Work, G E T Solutions, Inc. performed environmental analyses on samples obtained from boring locations 2019GETWB-28 and 2019GETWB-29. A composite soil sample was created from the split spoons collected from 0- to 2- and the 6- to 8-foot intervals below the mudline. The creation of the composite samples was accomplished by hand mixing the soil samples collected over that interval in clean, 5-gallon plastic buckets. The resultant composite soil samples were placed in appropriately preserved certified clean glass containers, labeled, packed on ice and delivered to the contract laboratory under chain-of-custody protocol for analysis for the presence and concentrations of the following analytes: sieve analysis with hydrometer (ASTM D422); PCB Congeners (EPA SW-846 1668) (Ref. Table 9-3 Inland Testing Manual); TPH-DRO & HRO, C10-C34 (EPA SW-846 8015B); PAHs (EPA SW-846 8270D) (Ref. Table 9-1 Inland Testing Manual); Metals (EPA SW-846 6020) (Ref. Table 9-1 Inland Testing Manual); Aluminum, Antimony, Arsenic, Barium, Beryllium, Cadmium, Chromium, Cobalt, Copper, Iron, Lead, Manganese, Mercury, Nickel, Selenium, Silver, Thallium, Tin, Vanadium, Zinc); Hexavalent Chromium (EPA SW-846 7199); and, Total Organic Carbon (Lloyd Kahn). The comprehensive laboratory results are provided in Appendix VIII for further evaluation by the responsible parties.

Naval Station Norfolk, Norfolk, Virginia G E T Report No.: VB19-314G

2.2.4 Compression Testing

Consolidated-Undrained Triaxial Compression tests (ASTM D4767) were performed on the soil specimens extracted from the Shelby tube samples at our Virginia Beach laboratory. More detailed information is provided in Appendix IX-Shelby Tube Classifications. The test results are presented in Table III and the comprehensive test results are provided in Appendix X.

Table III- Triaxial Test Results

Boring No.

Depth (Ft)

USCS

Classification

Angle of Internal Friction

Φ(1) (deg.)

Cohesion(1) c (psf)

2019GETB-23 65 ft. below grade CH Φ’=17.4 Φ=11.4 c’=540 c=620

2019GETWB-06 30 ft. below mudline CH Φ’=7.6 Φ=4.2 c’=1,090 c=1,152

2019GETWB-16 15 ft. below mudline CL Φ’=13.3 Φ=8.6 c’=70 c=102

1) Total and effective parameters are provided in the table. Effective is represented with a prime (‘) next to the parameter.

3.0 SITE AND SUBSURFACE CONDITIONS

3.1 Site Geology

The project site lies within a major physiographic province called the Atlantic Coastal Plain. Numerous transgressions and regressions of the Atlantic Ocean have deposited marine, lagoonal, and fluvial (stream lain) sediments. The regional geology is very complex, and generally consists of interbedded layers of varying mixtures of sands, silts and clays. Based on our review of existing geologic and soil boring data, the geologic stratigraphy encountered in our subsurface explorations generally consisted of marine deposited Sands, Silts and Clays.

The Yorktown Formation is one of the six stratigraphic units of the Coastal Plain. This formation consists of green-gray, over-consolidated clay and sand with marine shell fragments; it provides a suitable bearing stratum for pile support. Yorktown Formation soils were recovered from the SPT boring locations below elevations ranging from -21 to -88 feet NAVD88.

3.2 Recent Land Reclamation and Site Development

In order to obtain information regarding historical land use of the project site and its vicinity, we reviewed the 1978 map of the Geology of the Norfolk North Quadrangle, Virginia, topographic plans and aerial photographs. From this review, it appears that the project site consists of man-made fill land. A copy of a portion of the referenced map is provided in Appendix XI.

Naval Station Norfolk, Norfolk, Virginia G E T Report No.: VB19-314G

3.3 Existing Pavement Section Description

The results of our pavement cores are presented below, in Table IV. Pavement conditions may and are to be expected to vary at locations across the area of study.

Pavement section composition and descriptions are present in Appendix XII. The asphalt cores from boring locations 2019GETB-17, 2019GETB-18, and 2019GETB-22 deteriorated during extractions so pictures of these are not included in the appendix.

Table IV-Pavement Section Composition

Boring ID Asphalt Thickness (in.)

Cement Treated Aggregate Thickness

(in.)

Aggregate Base Material Thickness

(in.)

2019GETB-07 2 0 6

2019GETB-11 3.5 2 6.5

2019GETB-13 2.25 0 2

2019GETB-17 4 0 8

2019GETB-18 4.75 0 9

2019GETB-19 1.75 0 9

2019GETB-20 3 0 6

2019GETB-21 4.5 0 2.5

2019GETB-22 11.25 0 3

2019GETB-23 8.5 0 7

2019GETC-8 2.25 0 14

2019GETC-9 2.25 0 8

2019GETC-10 2.25 0 9.5

2019GETC-12 2.25 0 7

2019GETC-15 6.5 0 11.5

2019GETC-24 3.25 0 10

3.4 Subsurface Soil Conditions

The results of our review of the waterside SPT borings and CPTu probes are summarized in Table V, on the following page. The water level varied approximately 3 feet between low tide and high tide; the time the boring was started and the high and low tide for that date are described on each boring log. The results of the SPT borings were similar to the data from the CPTu probes; the CPTu data is provided in Appendix

XIII.

Naval Station Norfolk, Norfolk, Virginia G E T Report No.: VB19-314G

Table V – Subsurface Soil Conditions-Water Borings and Probes Average

Elevations

(ft. NAVD88)

Stratum Description Ranges of SPT(1) N-Values to

-27 to -46 Water 22 to 45 feet of water –

-27 to -46 to

-50 to -82

II

CLAY (CH, CL) and Organic CLAY (OH) with varying amounts of Sand and Silt

· 2019GETWB-28 and 2019GETWB-29 were terminated within this stratum.

WOH(2)-2

-50 to -82 to

-64 to -87

III

SAND (SC) with varying amounts of Clay

· This stratum was not recovered at boring locations 2019GETWB-03 and 2019GETWB-16 2-3

-64 to -87 to

-156 to -162 (boring termination depth)

IV

SAND (SM, SC, SP) with varying amounts of Silt, Clay and marine shell fragments.

CLAY (CH, CL) with varying amounts of Sand and marine shell fragments

Yorktown Formation

SAND: 2-19

CLAY: 6-13

Note(s): (1) SPT = Standard Penetration Test, N-Values in Blows-per-foot (uncorrected)

(2) WOH=Weight-of-Hammer

Naval Station Norfolk, Norfolk, Virginia G E T Report No.: VB19-314G

The soils recovered from the SPT land borings indicated the presence of uncontrolled fill material of differing thicknesses consistent with the understanding that this site is comprised of reclaimed land. Underlying the uncontrolled fill materials and water and extending to the boring termination depths the subsurface soils were generally arranged in a 4-layer configuration. A summary of the subsurface land-side soils is provided in Table VI.

Table VI – Subsurface Soil Conditions-Land Tests Elevation

(ft. NAVD88) Stratum Description Ranges of SPT(1) N-Values to

4 to -4

Uncontrolled Fill

SAND (SP-SM, SM) with varying amounts of Silt, Clay lenses, marine shell fragments, gravel, asphalt

3-44

4 to -4 to

-4 to -47 I

SAND (SM, SP, SP-SM) with varying amounts of Sand, marine shell fragments

· Borings 2019GETB-17, 2019GETB-19, 2019GETB-20, 2019GETB-21 were terminated within this stratum.

WOH(2)-27

-4 to -47 to

-8 to -76 II

CLAY (CH) and SILT (MH) with varying amounts of Sand

· This stratum was not recovered at 2019GETB-

11, 2019GETB-13

· Boring 2019GETB-22 was terminated within this stratum

2-5

-8 to -76 to

-23 to -88

III

SAND (SC, SM) with varying amounts of Clay, marine shell fragments and trace Gravel

· Boring 2019GETB-18 was terminated within this stratum

2-6

-23 to -88 To

Boring termination depth

IV

SAND (SC, SM) with varying amounts of Silt, Clay and marine shell fragments.

CLAY (CH, CL) with varying amounts of Sand and marine shell fragments

Yorktown Formation

SAND: 5-15

CLAY: 5-9

Note(s): (1) SPT = Standard Penetration Test, N-Values in Blows-per-foot (uncorrected)

(2) WOH=Weight-of-Hammer

The subsurface descriptions are of a generalized nature provided to highlight the major soil strata encountered. The records of the subsurface exploration are included in Appendix V (Boring Log sheets) and in Appendix VI (Generalized Soil Profiles) which should be reviewed for specific information as to the individual borings. The stratifications shown on the records of the subsurface exploration represent the conditions only at the actual boring locations. Variations may occur and should be expected between boring locations. The stratifications represent the approximate boundary between subsurface materials and the transition may be gradual.

Naval Station Norfolk, Norfolk, Virginia G E T Report No.: VB19-314G

3.5 Groundwater Discussion

The initial groundwater-level was recorded at the land SPT boring locations as observed through the relative wetness of the recovered soil samples during the drilling operations, and upon the completion of each of these borings. The initial groundwater level was measured to occur at depths ranging from 6 to 8 feet below the existing site grades.

The boreholes were left open from one day to the next to determine the 24-hour groundwater table depth. The soils caved in at most of the boring locations when removing the drilling equipment except for boring locations 2019GETB-11 and 2019GETB-23. The 24-hour groundwater table at these two locations was measured at

7.1 and 7.7 feet below grade. The boreholes were backfilled with a bentonite-grout mixture upon completion of testing for safety considerations. The groundwater depths corresponded to the water level in the adjacent waterway.

The soils encountered within these borings at the presumed groundwater levels consisted of relatively “clean” granular soils; thus, drilling fluids (water) were introduced into the boreholes during the drilling operations to prevent cave-ins from occurring, impairing the ability to accurately determine the groundwater levels. Therefore, the reported initial groundwater levels may not be indicative of the static groundwater level.

Groundwater conditions will vary with environmental variations, tidal fluctuations, and seasonal conditions, such as the frequency and magnitude of rainfall patterns, as well as man-made influences, such as existing swales, drainage ponds, underdrains and areas of covered soil (paved parking lots, sidewalks, etc.). Seasonal groundwater fluctuations of ± 3 feet are common in the project’s area; however, greater fluctuations have been documented particularly during extreme weather events.

4.0 EVALUATIONS AND RECOMMENDATIONS

Our recommendations are based on the previously discussed project information, our interpretation of the soil test borings and laboratory data, and our observations during our site reconnaissance. If the proposed construction should vary from what was described, we request the opportunity to review our recommendations and make any necessary changes.

Supporting calculations for the geotechnical evaluations are provided in Appendix XIV.

The existing CEP-176 bulkhead consists of concrete sheet piles, a concrete cap beam, and an anchor system with a concrete dead man and associated piles. This structure will remain in place; as such, the proposed HP-steel piles associated with the CEP-176 relieving platform should be planned so as not to interfere with the existing deep foundation system. It is recommended to remove any conflicting piles. Following that removal, all void spaces should be backfilled with clean granular soils. The proposed new piles should be installed a minimum of 1-foot away from any existing pile (1-foot pile face to pile face).

Naval Station Norfolk, Norfolk, Virginia G E T Report No.: VB19-314G

4.1 Clearing and Grading

The proposed construction areas should be cleared by means of demolishing structures, sidewalks, concrete pads, pavement section and any other unsuitable materials. It is estimated that a cut of up to 12 inches in depth will be required to remove the asphalt pavement (average asphalt thickness of 5 inches). Aggregate base material can be stockpiled and reused for the proposed paved areas if it meets the gradation requirements of VDOT 21A or 21B stone. This cut is expected to extend deeper in isolated areas to remove deeper deposits of unsuitable soils or materials, which become evident during the clearing. It is recommended that the clearing operations extend laterally at least 5 feet beyond the perimeter of the proposed construction area.

Uncontrolled FILL material may remain beneath the proposed on-grade supported structures (Gatehouse, Canopy and Guard Booth) and paved areas with the understanding that long term internal settlements are typically associated with them.

These settlements are difficult to quantify but are considered directly proportional to the amount of uncontrolled fill (height).

The site should be graded to enhance surface water runoff to reduce the ponding of water. Ponding of water often results in softening of the near-surface soils. In the event of heavy rainfall within areas to receive fill, we recommend that the grading operations cease until the site has had a chance to dry. If the subgrade becomes deteriorated due to the above-mentioned or other reasons, difficulty maneuvering construction equipment and machinery is likely.

The undercut and backfill should be performed under the observation of a representative of the testing agency who will evaluate the composition of the recovered soils. Recommendations concerning the subgrade improvements (as necessary) will be provided in the field following the testing procedures.

4.2 Subgrade Preparation

Following the clearing operation, the exposed subgrade soils should be densified with a large static drum roller. After the subgrade soils have been densified, they should be evaluated by the testing agency for stability. Accordingly, the subgrade soils should be proofrolled to check for pockets of loose material hidden beneath a crust of better soil.

Several passes should be made by a large rubber-tired roller or loaded dump truck over the construction areas. The number of passes will be determined in the field by the Geotechnical Engineer depending on the condition of the soil. Any pumping or unstable areas observed during proofrolling (beyond the initial cut) should be undercut and/or stabilized at the direction of the Geotechnical Engineer.

Naval Station Norfolk, Norfolk, Virginia G E T Report No.: VB19-314G

4.3 Select Fill and Placement

Any material to be used for select fill should be evaluated and tested by the testing agency prior to placement to determine if they are suitable for the intended use.

Suitable select fill material should consist of sand or gravel containing less than 20% of materials (per weight) passing through the No. 200 (opening 0.075 mm) Sieve (SP, SM, SW, GP, GW), having a liquid limit less than 20 and plastic limit less than 6, and should be free of rubble, organics, clay, debris and other unsuitable material.

All select fill should be compacted to a dry density of at least 95% of the Modified Proctor maximum dry density (ASTM D1557) unless specified differently in this report.

In general, the compaction should be accomplished by placing the fill in maximum 10-inch loose lifts and mechanically compacting each lift to at least the specified minimum dry density. The testing agency should perform field density tests on each lift as necessary to assure that adequate compaction is achieved.

Care should be used when operating the compactors near existing structures to avoid transmission of the vibrations that could cause settlement damage or disturb occupants.

In this regard, it is recommended that the vibratory roller remain at least 25 feet away from existing structures; these areas should be compacted with small, hand-operated compaction equipment.

4.4 Suitability of On-site Soils

Based on the laboratory testing program, the shallow subsurface Uncontrolled FILL material consisted of SAND (SM, SP, SP-SM) soils, relatively free of deleterious debris.

Debris is typically considered unsuitable consists of wood, glass, organics, plastics, coal, brick or any other material larger than 2 inches in diameter. These materials appear to meet the criteria recommended in this report for reuse as select fill if properly compacted (as detailed in Section 4.3). Further classification testing (natural moisture content, gradation analysis, and Proctor testing) should be performed in the field during construction to evaluate the suitability of excavated soils for reuse as select fill. The project’s budget should include an allowance for imported select fill.

4.5 Guard Booth, Gatehouse and Canopy

The Gatehouse and Canopy should be supported on shallow foundations and slab-on-grade and the Guard Booth on a mat foundation. Two options are proposed to manage the uncontrolled FILL materials. The first option consists of removing all uncontrolled FILL from the footprint of these structures which will result in settlement magnitudes within industry standards. However, this approach will result in excavations of 4 feet at the Guard Booth and 8 feet at the Gatehouse and Canopy. The resulting excavations should be backfilled with compacted select fill as described in Section 4.3.

Naval Station Norfolk, Norfolk, Virginia G E T Report No.: VB19-314G

The second alternative consists of constructing these structures on the in-situ FILL materials which have high Standard Penetration Test and Cone Penetrometer test resistances and an average California Bearing Ratio of 16.8. These parameters as well as the recovered soils are indicative of compacted material that should perform well to support these structures. If the uncontrolled FILL materials are left in place, isolated areas (particularly slab areas) may experience settlements slightly greater than industry standards. Substantial field testing was performed within these in-situ fill areas to obtain a comfort level justifying shallow foundations bearing upon the in-situ fill soils; as such, it is our opinion that the risk of settlement magnitudes above industry standard is minimal.

4.5.1 Foundation Excavations-Guard Booth, Gatehouse & Canopy

The foundation bearing capacities should be verified in the field during construction by means of performing a footing inspection for each foundation structure. At that time, the Geotechnical Engineer should also explore the extent of excessively loose, soft, or otherwise unsuitable material within the exposed excavations. Also, at the time of footing observations, the Geotechnical Engineer should advance hand auger borings or use a hand penetration device in the bases of the foundation excavations to verify that the recovered soils are consistent with those documented in this report. The necessary depth of penetration will be established during the subgrade observations.

The proposed footing elevation should be re-established by means of backfilling with “flowable fill”, suitable select fill material compacted to a dry density of at least 95% of the Modified Proctor maximum dry density (ASTM D 1557), as described in Section 4.3 of this report, or VDOT No. 57 Stone prior to concrete placement. This construction procedure will provide for a net allowable bearing capacity of 2,000 pounds per square foot (psf) provided that minimum foundation diameters are maintained.

Immediately prior to reinforcing steel placement, it is suggested that the bearing surfaces of all footing and floor slab areas be compacted using hand operated mechanical tampers, to a dry density of at least 95% of the Modified Proctor maximum dry density (ASTM D 1557) as tested to a depth of 12 inches, for bearing capacity considerations. In this manner, any localized areas, which have been loosened by excavation operations, should be adequately re-compacted.

Soils exposed in the bases of all satisfactory foundation excavations should be protected against any detrimental change in condition such as from physical disturbance, rain or frost. Surface run-off water should be drained away from the excavations and not be allowed to pond. If possible, all footing concrete should be placed the same day the excavation is made. If this is not possible, the footing excavations should be adequately protected.

Naval Station Norfolk, Norfolk, Virginia G E T Report No.: VB19-314G

4.5.2 Shallow Foundation Design Recommendations-Gatehouse & Canopy

Provided that the construction procedures are properly performed, the Gatehouse and Canopy should be supported by isolated spread footings bearing upon well-compacted select fill material. These footings can be designed using a net allowable soil pressure of 2,000 pounds per square foot (psf). In using net pressures, the weight of the footings and backfill over the footings, including the weight of the floor slab, need not be considered. Hence, only loads applied at or above the finished floor need to be used for dimensioning the footings.

To develop the recommended bearing capacity of 2,000 pounds per square foot (psf), the base of the footings should have a minimum embedment of 18 inches beneath finished grades and should have a minimum width of 24 inches. In addition, isolated square column footings (if deemed necessary) are recommended to be a minimum of 3 feet by 3 feet in area for bearing capacity consideration. The recommended 18-inch footing embedment is considered sufficient to provide adequate cover against frost penetration to the bearing soils.

4.5.3 Settlements-Gatehouse & Canopy

It is estimated that, with proper site preparation, the maximum resulting post-construction total settlement of the foundations of the proposed structures should be up to 1 inch. The maximum differential settlement magnitude is expected to be less than ½ -inch between adjacent footings (footings of widely varying loading conditions). The settlements were estimated on the basis of the results of the field penetration tests.

Careful field control will contribute substantially towards minimizing the settlements.

If the uncontrolled FILL materials are left in place beneath the structures, isolated areas (particularly slab areas) may experience settlements slightly greater than industry standards.

4.5.4 Slab-on-Grade Design-Gatehouse & Canopy

Floor slabs may be constructed as slab-on-grade members provided the previously recommended earthwork activities and evaluations are carried out properly. It is recommended that all ground floor slabs be directly supported by at least a 4-inch layer of relatively clean, compacted, poorly graded sand (SP) or gravel (GP) with less than 5% passing the No. 200 Sieve (0.074 mm). The purpose of the 4-inch layer is to act as a capillary barrier and equalize moisture conditions beneath the slab. A subgrade modulus of 125 pounds per square inch per inch (psi/in) should be used when analyzing the slabs under this construction procedure. Alternately, the concrete slabs may be directly supported by a 6 to 8-inch layer of well-compacted aggregate base stone (VDOT 21A or 21B). Furthermore, a subgrade modulus of 150 pounds per square inch per inch (psi/in) should be used when analyzing the slabs under this construction procedure.

Naval Station Norfolk, Norfolk, Virginia G E T Report No.: VB19-314G

4.5.5 Guard Booth-Mat Foundation Recommendations

The guard booth should be supported on a mat foundation which will bear on compacted select fill materials as described in Section 4.5.1 and can be designed for a modulus of subgrade reaction of 125 psi/in.

· Mat Embedment: The base of the guard booth should be embedded a minimum of

12 inches below grade to provide adequate cover against frost penetration to the bearing soils.

· Settlement: It is estimated that the maximum resulting post-construction total settlement of the mat should be up to 1 inch. The maximum differential settlement magnitude is expected to be less than ½ -inch between opposite corners of the mat.

· Mat Subgrade: The mat foundation subgrade soils should be relatively firm, dry, smooth and free of debris and loose material prior to installing concrete and reinforcing steel (if required). This should be verified by a field inspector prior to foundation construction. The subgrade below the mat foundation should be relatively level and free of high points which may cause stress concentrations.

Therefore, we recommend that a 12-inch thick layer of No. 57 stone be provided in the base of the excavation to allow for more uniform bearing.

· Quality Assurance: We recommended that a representative of the testing agency be on site to verify that the foundation is bearing on competent materials anticipated by the soil boring and that the foundation installation procedures comply with the specifications.

4.6 Pavement Design Recommendations

The relieving platform for CEP-176, the roadways (3rd Street, B Avenue), and parking areas within the proposed construction site are planned to be paved. Pavement design depends on the characteristics of the subgrade soils and the traffic loading conditions.

California Bearing Ratio (CBR) tests were performed to determine the strength of the subgrade soils.

The collected bulk soil samples in the footprint of the land portion of the site have an average soaked CBR value of 16.8. The average soaked CBR value was multiplied by a factor of two-thirds to determine a pavement design CBR value; this safety factor is typically used in roadway design. The two-thirds factor provides the necessary safety margins since the specified time for soaking may not be long enough to give the minimum CBR strength of some soils, to compensate for any non-uniformity of the soil, and to account for any low test results not considered when computing the average.

Therefore, a CBR value of 11.2 should be used in designing the pavement sections landside of the proposed construction site.

Naval Station Norfolk, Norfolk, Virginia G E T Report No.: VB19-314G

The pavement section at the proposed CEP-176 relieving platform and Pier 3 is expected to bear on roughly 5 feet of compacted select fill which should have a design CBR value of 15 or more. The rest of the proposed paved areas are expected to bear on the in-situ uncontrolled FILL materials; due to the heterogeneous nature of these materials, differential settlements are possible and could result in pavement cracking or isolated pavement depressions. The pavement sections were calculated based on the pavement design methods of the 1993 AASHTO Guide for Design of Pavement Structures, the Virginia Department of Transportation (VDOT) design criteria, and our experience with similar types of applications.

Parking Bays, Average Daily Traffic < 1,000 Vehicles per day (VPD)

· Surface Asphalt SM-12.5A: 2.0 inches.

· Aggregate Base Material 21A or 21B: 8 inches.

· Subgrade: Stable, compacted to at least 95% of the Modified Proctor maximum dry density (ASTM D1557), and approved by the Geotechnical Engineer.

Roadways, Average Daily Traffic < 5,000 VPD

· Surface Asphalt SM-12.5A: 2.0 inches.

· Base Asphalt BM-25.0A: 3 inches.

· Aggregate Base Material 21A or 21B: 8 inches.

· Subgrade: Stable, compacted to at least 95% of the Modified Proctor maximum dry density (ASTM D1557), and approved by the Geotechnical Engineer.

CEP-176 Relieving Platform (Average Daily Traffic < 200 VPD, 90% truck traffic)

· Surface Asphalt SM-12.5A: 2.0 inches.

· Intermediate Asphalt IM-19.5A: 2.5 inches.

· Base Asphalt BM-25.0A: 3.0 inches.

· Aggregate Base Material 21A or 21B: 8 inches.

· Subgrade: Stable, compacted to at least 95% of the Modified Proctor maximum dry density (ASTM D1557), and approved by the Geotechnical Engineer.

In preparation for a stable subgrade support for pavement, the following construction steps are recommended:

1. Following pavement rough grading operations, the exposed subgrade should be observed under proofrolling. This proofrolling should be accomplished with a fully loaded dump truck or 7 to 10 ton drum roller to check for pockets of soft material hidden beneath a thin crust of better soil. Any unsuitable materials thus exposed should be removed and replaced with a well-compacted material. The inspection of these phases should be performed by a qualified Geotechnical Engineer or designated representative.

Naval Station Norfolk, Norfolk, Virginia G E T Report No.: VB19-314G

2. Where excessively unstable subgrade soils are observed during proofrolling and/or fill placement, it is expected that these weak areas can be stabilized by means of thickening the base course layer. These alternates are to be addressed by a qualified Geotechnical Engineer or designated representative during construction, if necessary, who will recommend the most economical approach at the time.

4.7 Combi-walls CEP-176 & CEP-102

Bulkhead CEP-176 will be constructed as a combi-wall consisting of a combination of steel pipe piles and sheet piles. Design grade will be raised 5 feet from existing grades inland of bulkhead CEP-176. A 100-foot wide relieving platform will support the fill to attain design grade. The relieving platform will be supported on HP-steel piles.

Bulkhead CEP-102 will be constructed as a combi-wall (combination of steel pipe piles and steel sheet piles) from the proposed Pier 3 to Station 3+50; and from Station 3+50 to 9+00 it will consist of steel sheet piles only (not a combi-wall). The design elevation of the wharf in front of CEP-102 will remain the same as existing grades. Soil parameters to aid in the design of the bulkheads, pipe pile capacities, steel pile capacities, and sheet piles are provided in the following sub-sections of the report.

4.7.1 Soil Parameters for Bulkheads

Different soil conditions were evaluated along the alignments of the bulkheads. The soil conditions also varied inland and waterside of the bulkheads. Generalized subsurface profiles were created for each of the bulkheads (inland and waterside) from the current and previous geotechnical explorations. Additionally, the transition between the different soil conditions were identified in the berthing plan as Boundaries AA, BB, CC, DD, and EE. The project station numbers at which the transition between different soil conditions occurs are listed below.

· Boundary AA-inland of Bulkhead CEP-102: Station 3+50

· Boundary BB-inland CEP-176: Station 7+25

· Boundary CC-water side CEP-102: Station 2+50

· Boundary DD- water side CEP-176: Station 5+75

The generalized subsurface profiles and berthing plan are provided in Appendix XV and should be reviewed in conjunction with the soil parameters presented in Table VII through Table XIV (on the following pages). The elevations of the strata presented in the tables are listed from south to north for bulkhead CEP-102, and from west to east for bulkhead CEP-176.

Naval Station Norfolk, Norfolk, Virginia G E T Report No.: VB19-314G

Consideration should be given to the hydrostatic pressures when analyzing the proposed bulkheads’ performances. These pressures should take into consideration the tidal fluctuations at the site. Also, appropriate safety factors should be maintained against a kick-out and overturning failure.