EMI_Final_Geotechnical_Design_Report_-_(Submitted_10-12-2018).pdf

Earth Mechanics, Inc.

Geotechnical & Earthquake Engineering

17800 Newhope Street, Suite B, Fountain Valley, California 92708 Tel: (714) 751-3826 Fax: (714) 751-3928

October 12, 2018 EMI Project No. 17-111

Moffatt & Nichol 1660 Hotel Circle North, Suite 500 San Diego, CA 92108

Attention: Mr. Alan Alcorn P.E.

Project Manager

Subject: Final Geotechnical Design Report FY19 MCON Project P-224 Causeway, Boat Channel, and Turning Basin & FY20 MCON Project P-226 Ammunition Pier, Naval Weapon Station, Seal Beach, California

Dear Mr. Alcorn:

Please find attached the final Geotechnical Design Report for the subject project. This report contains the details of subsurface characterization, design and construction recommendations for the subject project.

We appreciate the opportunity to work with you on this project. If you have any questions, please do not hesitate to call us.

Sincerely, EARTH MECHANICS, INC.

Amin Rahmani, Ph.D., PE 88621

Senior Staff Engineer

Raj S. Varatharaj, GE 2787 Senior Engineer

Arul K. Arulmoli, Ph.D., GE 2090 Project Manager

FINAL GEOTECHNICAL DESIGN REPORT

FY19 MCON PROJECT P-224 CAUSEWAY, BOAT CHANNEL, AND TURNING BASIN

& FY20 MCON PROJECT P-226 AMMUNITION PIER

NAVAL WEAPON STATION, SEAL BEACH, CALIFORNIA

Prepared For:

Moffatt & Nichol 1660 Hotel Circle North, Suite 500

San Diego, CA 92108

Prepared By:

Earth Mechanics, Inc.

17800 Newhope Street, Suite B

Fountain Valley, California 92708

EMI Project No. 17-111 October 12, 2018

TABLE OF CONTENTS

Section Page

1.0 INTRODUCTION

1.1 Purpose

1.2 Project Description

1.3 Scope of Work

2.0 SITE GEOLOGY, SEISMIC CONSIDERATIONS AND

SUBSURFACE CONDITIONS

2.1 Geologic Setting

2.1.1 Geologic Hazards

2.1.2 Stratigraphy:

2.1.3 Seismicity

2.2 Site-Specific Seismic Hazard Study

2.3 Site Classification

2.4 Liquefaction Potential and Seismically-Induced Settlement

2.5 Subsurface Conditions

3.0 ANALYSES, CONCLUSIONS AND RECOMMENDATIONS

3.1 Seismically Induced Settlements

3.2 Slope Stability Analyses and Recommendations

3.2.1 Breakwater Stability

3.2.2 Causeway Stability during Construction

3.2.3 Truck Turnaround Area Stability during Construction

3.2.4 Jetties at Public Navigation Channel (PNC)

3.3 Ammunition Pier Piles

3.3.1 Axial Capacity Recommendation for Ammunition Pier Piles

3.3.2 Lateral (p-y) Springs Recommendations for Ammunition Pier Piles

3.3.3 Axial Capacity and Lateral (p-y) Spring Recommendations for Southwest Mooring Dolphin Piles

3.3.4 Axial Capacity Recommendations for Northeast Mooring Dolphin Piles

3.3.5 Construction Consideration for Pile Driving

3.4 Fender Piles

3.5 Proposed Mooring Dolphins at Wharf 311

3.5.1 Axial Capacity Recommendation for MD Piles

3.5.2 Lateral (p-y) Spring Recommendations for MD Piles

3.5.3 Kinematic Loads on MD Piles Due to Slope Displacement

3.5.4 Construction Consideration for Pile Driving

3.6 Settlement and Surcharge Recommendations

3.7 Foundation Recommendations for the Proposed South Mole Buildings

3.8 Recommendations for Retaining Walls

3.9 Earthwork Recommendations

3.10 Dredge Slopes During Construction

3.11 R-Value Test Results

3.12 Soil Corrosivity

4.0 LIMITATIONS

5.0 REFERENCES

LIST OF FIGURES

Figure Title Page

Figure 1-1 Project Location Map Figure 1-2 Proposed Improvements of P-224 Causeway, Boat Channel, and Turning Basin project Figure 1-3 Proposed Improvements of P-226 Ammunition Pier Project Figure 2-1 Regional Geology Figure 2-2 Site Fault Map Figure 2-3 Acceleration Response Spectra for OLE Earthquake with Various Spectral

Damping Ratios Figure 2-4 Acceleration Response Spectra for CLE Earthquake with Various Spectral

Damping Ratios Figure 2-5 Acceleration Response Spectra for Design Earthquake with Various Spectral

Damping Ratios Figure 2-6 Relative Displacement Spectra for OLE Earthquake with Various Spectral

Damping Ratios Figure 2-7 Relative Displacement Spectra for CLE Earthquake with Various Spectral

Damping Ratios Figure 2-8 Relative Displacement Spectra for Design Earthquake with Various Spectral

Damping Ratios Figure 2-9 Locations of Sections and Site-Specific Explorations Map Figure 2-10 Longitudinal Section A-A’ Figure 2-11 Cross Section X-X’ Figure 2-12 Cross Section B-B’ Figure 2-13 Cross Section C-C’ Figure 3-1 Pile Configuration and Recommended Pile Elevations Figure 3-2 Ultimate Axial Pile Capacity of Proposed 24-inch Octagonal Concrete Piles for

Northeast Mooring Dolphins Figure 3-3 Ultimate Axial Pile Capacity of Proposed 24-inch Octagonal Concrete Piles for

Southwest Mooring Dolphins Figure 3-4 Ultimate Axial Pile Capacity of Proposed 48-inch Steel Pipe Piles for East Mooring

Dolphin at Wharf 311 (static conditions) Figure 3-5 Ultimate Axial Pile Capacity of Proposed 48-inch Steel Pipe Piles for West Mooring

Dolphin at Wharf 311 (static conditions) Figure 3-6 Ultimate Axial Pile Capacity of Proposed 48-inch Steel Pipe Piles for East and West

Mooring Dolphins at Wharf 311 (seismic conditions) Figure 3-7 Kinematic Loading Profile induced at 48-inch Steel Pipe Piles at the location of East and West Mooring Dolphins – Wharf 311

LIST OF TABLES

Table Title Page

Table 2-1 Summary of Design Earthquake Parameters Table 2-2 Summary of Liquefaction Analysis Results Under Existing Conditions during

OLE and CLE Earthquake Events Table 2-3 Idealized Soil Profiles and Strength Parameters Table 3-1 Results of Slope Stability Analyses Table 3-2 Results of Slope Stability Analyses Table 3-3 Summary of R-Value Test Results (East Mole) Table 3-4 Summary of R-Value Test Results (Anaheim Bay Road) Table 3-5 Summary of Existing Pavement Section (Anaheim Bay Road) Table 3-6 Summary of Soil Corrosivity Test Results

APPENDICES

Appendix A Liquefaction Potential And Seismic Settlement Calculations Appendix B Slope Stability Calculations Appendix C Axial Pile Capacity Calculations And P-Y Spring Recommendations Appendix D Consolidation Settlement Calculations Appendix E Settlement Monitoring Program Appendix F Pile Penetrability Study

1.0 INTRODUCTION

1.1 Purpose

This report presents the subsurface characterizations, design and construction recommendations for the proposed P-224 Causeway, Boat Channel, and Turning Basin and P-226 Ammunition Pier located at the Naval Weapons Station, Seal Beach, California. The Project Location Map is shown in Figure 1-1. The work was performed by Earth Mechanics, Inc. (EMI) under a subcontract agreement with Moffatt & Nichol (M&N).

1.2 Project Description

The proposed Ammunition Wharf and Turning Basin project will be constructed as two different projects called P-224 Causeway, Boat Channel, and Turning Basin and P-226 Ammunition Pier.

The proposed P-224 project elements (see Figure 1-2) include dredging a large area for turning basin including a portion of West Mole, and constructing a causeway (approximately 930 ft long), a public boat navigation channel, a breakwater near the south end of proposed pier and mooring dolphins at the east and west ends of the existing wharf 311.

P-226 project elements (see Figure 1-3) include ammunition pier supported on prestressed concrete piles (approximately 1,095 ft long and 125 ft wide), mooring dolphins at both ends of the pier, fender system for loading and offloading operations of ammunition, truck turnaround area, small single story pier office building, restroom and charging buildings along the East Mole roadway. Based on the information provided by the designers, the design mudline elevation at the face of the proposed pier is -39 ft Mean Lower Low Water (MLLW).

1.3 Scope of Work

EMI’s scope of work was as follows:

Interpret field and laboratory results to develop idealized soil profiles and strength parameters for analyses based on current and available past geotechnical investigation documented in Final Geotechnical Data Report (EMI, 2018a).

Provide Acceleration Response Spectrum (ARS) and Relative Displacement Spectrum (RDS) recommendations for the project based on the site-specific probabilistic seismic hazard analysis (PSHA) (EMI, 2018b).

Evaluate site-specific seismic hazards including liquefaction potential, liquefaction-induced settlement and embankment lateral slope deformation during multiple levels of earthquakes.

Provide foundation recommendations for the proposed pier, mooring dolphins, various buildings, and other miscellaneous structures.

Evaluate consolidation settlements due to fill placement at Truck Turnaround area, along the proposed Causeway, and the future east and west jetties at Public Navigation Channel (PNC) area.

Provide construction considerations from geotechnical perspectives for earthwork, subgrade preparations and for pile driving.

Prepare this report documenting the findings, conclusions, and recommendations.

Project Location Map

Figure 1-1

P-224 CAUSEWAY, BOAT CHANNEL, AND TURNING

BASIN & P-226 AMMUNITION PIER

Project No. 17-111 Date: 10-11-2018

SITE

N

Geotechnical and Earthquake Engineering

P-224 CAUSEWAY, BOAT CHANNEL, AND TURNING BASIN

NAVAL WEAPON STATION, SEAL BEACH, CALIFORNIA

Date: 10-11-2018EMI Project Number: 17-111

Proposed Improvements - Project P-224

Figure 1-2

NORTHEAST MOORING DOLPHIN

SOUTHWEST MOORING DOLPHIN

Earth Mechanics, Inc.

Geotechnical and Earthquake Engineering

P-226 AMMUNITION PIER

NAVAL WEAPON STATION, SEAL BEACH, CALIFORNIA

Date: 10-11-2018EMI Project Number: 17-111

Proposed Improvements - Project P-226

Figure 1-3

Geotechnical & Earthquake Engineering

2.0 SITE GEOLOGY, SEISMIC CONSIDERATIONS AND SUBSURFACE

CONDITIONS

2.1 Geologic Setting

The subject site is located within the Seal Beach, California 7.5-Minute Topographic Quadrangle. Regionally, the subject property is situated within the northern portion of the Peninsular Ranges Geomorphic Province of southern California. The Peninsular Ranges Geomorphic Province consists of a series of northwest-trending mountain ranges, valleys, and similar oriented faults. The province extends from the Transverse Ranges southward to the tip of the Baja California Peninsula. The width of the province in southern California extends from the Pacific Ocean in the west to the Colorado Desert in the east. The Peninsular Ranges province is a seismically active region characterized by structural blocks separated by a series of northwest-trending strike slip faults. These faults are a part of or related to the San Andreas Fault System.

The most prominent of these faults near the site area is the Newport-Inglewood structural zone, which is known to have been active during the Quaternary time.

Locally, the subject site is located within the coastal plain portion of the Los Angeles Basin. A review of published and unpublished reports and maps indicates the site is underlain primarily by unconsolidated marine shelf sediments with poorly consolidated paralic estuarine and beach deposits near the shoreline (Saucedo et al., 2003). Figure 2-1 shows the Regional Geology in the site area.

2.1.1 Geologic Hazards

The California Geological Survey does not show any active faults within the project site (Jennings, 2010). The nearest known major active faults are the Newport-Inglewood Structural Zone about 0.6 miles northeast of the site, the Palos Verdes fault about 6.9 miles to the southwest, in the offshore area, and the Whittier-Elsinore fault about 17.2 miles to the northeast.

Landslides: The risk for land sliding is considered low. No major slopes are proximal to the site as the local topography is generally flat with some minor artificial slopes/embankments.

Flooding: The risk related to flooding should be considered moderate as much of the site is within well developed areas that maintain storm drainage and water run-off control, however the site is within a few feet of sea level therefore storm-surge and/or extreme high tides may inundate the site. The FEMA Flood Insurance Rate Map (FEMA, 2009) shows that the project site is designated as Zone D (Undetermined Flood Risk).

Tsunami: The site is located within a tsunami inundation area (CGS, 2009). The energy released from a significant earthquake on a local or distant fault, the site is subject to inundation from tsunami run-up. Tsunamis are rare events and no data about the probability of a tsunami affecting the site in the future is provided.

2.1.2 Stratigraphy:

Artificial Fill (af): Artificial fill was encountered at depths of up to approximately 10 to 15 feet in the majority of the landside borings. The fill generally consists of light brown to grayish brown, sand and silty sand.

Beach Deposits (Qb): Quaternary beach deposits were observed in the area of the eastern mole consisting of brown to gray, sands with silt, and silty sands.

Geotechnical & Earthquake Engineering

Paralic Estuarine Deposits (Qpe): These deposits overlie the older paralic deposits and consist of interbedded, discontinuous beds of brown to gray, sandy silt, clay and silty sand. Shell fragments are common.

Old Paralic Deposits (Qopa): The older paralic deposits have a similar composition to the overlying younger deposits and are differentiated from them by increasing density.

Unconsolidated Shelf Deposits (Qms): In the bay, harbor and offshore areas, unconsolidated shelf deposits were encountered consisting of loose fine-grained, sands and silts.

2.1.3 Seismicity

The project is in seismically active southern California. Seismicity in the Los Angeles-Orange County region is widespread but it does not always clearly correlate to specific surface faults.

Seismicity of smaller magnitude (magnitudes smaller than about 3) occur randomly and frequently throughout the region. There are several active faults within 20 miles of the site that could produce significant ground shaking. Figure 2-2 shows the site in relation to major faults in the region.

The Newport-Inglewood Fault Zone is located approximately 0.6 miles northeast of the project site. The fault zone is expressed as a series of discontinuous faults and folds extending from the Santa Monica fault at its northern end to the Newport Beach area where it trends offshore. The southern limit of the Newport-Inglewood fault zone continues offshore nearly parallel to the coastline to about the Dana Point-San Clemente area based on offshore geophysical data. The fault is considered capable of producing a magnitude 6.9 to 7.2 earthquake. The magnitude 6.25 Long Beach earthquake of 1933 occurred on the Newport-Inglewood fault. The epicenter of the earthquake was offshore near Newport Beach.

The Palos Verdes fault Zone is located approximately 6.9 miles southwest of the project site. The fault zone is expressed as a series of enechelon faults extending from the Palos Verdes Peninsular to the southeast offshore where it continues southward as the Palos Verdes-Coronado Bank fault. The fault is considered capable of producing a magnitude 6.0 to 7.0 (Mw) earthquake

(SCEDC, 2018).

The Whittier segment of the Elsinore Fault is located approximately 17 miles northwest of the proposed project. The Elsinore fault system has faults with many types of displacement (strike slip, normal, reverse) but is predominantly a right-lateral strike-slip fault with a large normal component. The Elsinore fault system is more than 100 miles long, and may be interconnected with faults in Mexico such as the Laguna Salada fault and the Whittier and Chino faults on the north. The great length of the zone suggests it is capable of generating large-magnitude earthquakes, with a maximum earthquake of 7.7 magnitude (Mw) estimated by Caltrans (2012a).

Ground Rupture: The potential for surface fault rupture at the project site is anticipated to be low. In addition, per Caltrans Memo to Designer 20-10 (Caltrans, 2013), since the subject structures do not fall within an Alquist-Priolo Earthquake Fault Zone or within 1,000 feet of an unzoned fault that is Holocene or younger in age, further fault studies will not be needed.

2.2 Site-Specific Seismic Hazard Study

Detailed site-specific seismic hazard analysis was performed and documented in a report by EMI (EMI, 2018b). Details of seismic sources and characteristics that influence the ground shaking at the project site can be found in the seismicity report.

Geotechnical & Earthquake Engineering

Per Unified Facilities Criteria for Design of Piers and Wharves (UFC 4-152-01, 2017), earthquake loads should be determined following procedures and methods contained in ASCE/COPRI Seismic Design of Piers and Wharves (ASCE, 2014) known as ASCE 61. Seismic design per ASCE 61 requires the wharf to be designed for three levels of earthquakes as summarized in Table 2-1 below. The UFC 4-152-01 requires that the Design Earthquake (DE) be obtained using the procedures specified in ASCE 7-10 (ASCE, 2010). Peak ground accelerations based on the site-specific seismic hazard analysis (EMI, 2018b) for these three levels of earthquakes are also provided in Table 2-1.

The Acceleration Response Spectra (ARS) for Operational Level Earthquake (OLE ) (72 year return period), Contingency Level Earthquake (CLE) (475 year return period) and Design Earthquake (DE) for various damping ratios are provided in Figures 2-3, 2-4 and 2-5, respectively. The relative displacement spectra for OLE, CLE and DE are provided in Figures 2- 6, 2-7 and 2-8, respectively.

Table 2-1 Summary of Design Earthquake Parameters

Earthquake Event Probability of

Exceedance in 50 Year (Return Period)

Peak Ground Acceleration

(PGA)

Earthquake Magnitude

OLE 50% (72 yrs) 0.19g 7.81

CLE 10% (475 yrs) 0.43g 7.0

DE per UFC 3-310-04 N/A 0.49g 7.0

Note 1. In probabilistic seismic hazard analysis (PSHA), hazard contribution comes from various faults located at different distances from the site. The seismic hazard for OLE is from a combination of smaller events on nearby faults, and larger events on more distant faults. There are multiple magnitude-distance scenarios that significantly contribute to this hazard level for the site. The modal magnitude-distance pair (i.e., the more likely pair) for peak ground acceleration (PGA) is the M 7.8 event at 50.5 miles (South San Andreas Fault) which happens to be the fault with the capability to generate the largest earthquake in the region.

2.3 Site Classification

Site Class F is designated for the site under OLE, CLE and DE due to the presence potentially liquefiable materials.

2.4 Liquefaction Potential and Seismically-Induced Settlement

Liquefaction Potential of Coarse-Grained Soils: The liquefaction potential of the saturated, granular materials below the water table in the vicinity of the site was evaluated using the procedures outlined by Seed et al. (1983) and updated by NCEER (1997), SCEC (1999), and Youd et al. (2001).

The field SPT N-value /CPT tip resistance was normalized with all the recommended corrections. The available cyclic shear resistance of the potentially liquefiable soils was estimated based on the normalized SPT N-value /CPT tip resistance and compared to the cyclic shear stress that would be induced by an expected level of earthquake to determine the potentially liquefiable zones.

Liquefaction potential and consequences evaluations for building sites should be performed using PGAM [Maximum Credible Earthquake Peak Ground Acceleration (MCEG)] per IBC

Geotechnical & Earthquake Engineering

2015/ACSE 7-10 (IBC, 2015; ASCE, 2010). A PGAM of 0.76g was used in liquefaction and consequences evaluations for MCE event at building site (EMI, 2018b)

Liquefaction Potential of Fine-Grained Soils: Plasticity index (PI) is a better indicator of liquefaction susceptibility or cyclic softening of claylike fine-grained soils. Per Boulanger and Idriss (2006), soils with PI>7 are considered not susceptible to liquefaction.

Seismically-Induced Settlement of Coarse-Grained Soils: The liquefied soils reconsolidate during and after earthquake shaking, leading to ground settlement. The scale of ground surface settlement depends on several factors such as characteristics of the soil, level and duration of shaking, and extent of the liquefaction zone. For granular soils, the seismically-induced settlements were estimated using the procedures outlined by Tokimatsu and Seed (1987). The estimated seismically-induced settlement values are approximate and may vary depending on several factors, such as layered nature of subsurface soils, amount of fine contents, and excess pore pressure dissipation pattern of fine-grained soils.

Seismically-Induced Settlement of Fine-Grained Soils: According to Boulanger and Idriss (2006), soils with PI>7 are not susceptible to liquefaction and the seismically-induced vertical settlement is anticipated to be negligible.

It is our understanding that the proposed truck turnaround area and the causeway will be constructed using fill materials. Granular fill materials are anticipated to be loose to medium dense state after the construction and are potentially liquefiable and may settle during seismic events. Seismically induced settlement up to 18 inches can be anticipated depending on the thickness of the new fill.

Silts and silty sands found at Wharf 311 are anticipated to liquefy under the design earthquake events. Due to presence of clayey soils at the west end of the wharf, potential for liquefaction at the west end of the wharf appears to be less than that at the east end. The estimated seismically-induced settlements are up to 3 inches and up to 13 inches at west and east ends of the wharf, respectively.

Summary of liquefaction potential and seismically-induced settlement estimates is provided in Table 2-2. Spreadsheets used for the calculation of liquefaction potential and seismically induced settlement evaluations are provided in Appendix A.

Table 2-2 Summary of Liquefaction Analysis Results Under Existing Conditions during OLE and CLE Earthquake Events

Boring / CPT Sounding No.

Approximate Elevations of Liquefiable Zones (ft MLLW)

Approximate Seismically induced Settlement (inches)

Under OLE Under CLE OLE CLE(1)

Borings/CPT Soundings Along the New Pier

OB-1 -47.5 to -57.5 -47.5 to -57.5 3.7 3.8

OB-2 -56.5 to -61.5 -56.5 to -61.5 1.1 1.1

OB-3 - - - 0.4

OB-4 -43 to -45.5 -43 to -45.5 0.5 0.5

LB-2 - - - -

17-C-1 - -10.8 to -12.8 - 0.3

Geotechnical & Earthquake Engineering

2.5 Subsurface Conditions

Subsurface conditions at the site were evaluated using information gathered from past geotechnical investigations and the current site-specific geotechnical investigations by EMI.

Details of available subsurface information and site-specific investigations are provided in a separate data report prepared by EMI (EMI, 2018a).

A longitudinal section (A-A’) and a cross-section (X-X’) were developed at the east mole using the data from site-specific subsurface explorations to characterize the subsurface conditions.

Locations of sections and site-specific explorations are shown in Figure 2-9. Sections A-A’ and X-X’ (Figures 2-10 and 2-11) show the subsurface conditions. Subsurface conditions of the project site are briefly described below.

Based on the available and additional site-specific subsurface information, within the East Mole, subsurface materials at shallow depths down to approximate El. -10 ft MLLW consist of medium dense to very dense silty sand. Rocks of varying sizes are found on slopes of the mole and at shallow depths. Very stiff and hard clay layers with varying thickness of several feet interbedded with very dense silty sand and clayey sand were encountered between El. -10 ft and El. -40 ft MLLW. Below El. -40 ft within the East Mole and below approximately 3 to 5 ft of harbor sediments outside the mole, the subsurface materials consist of very dense silty sand materials. In the vicinity of the southwest end of the wharf and breakwater, subsurface materials down to approximate El. -60 ft MLLW consist of soft clay and very loose sandy materials. Idealized soil parameters developed for geotechnical analyses based on the information obtained from soil boring, laboratory test results and engineering judgment are provided in Table 2-3.

Subsurface materials along the proposed causeway consist of varying thickness of soft harbor bottom sediments up to 15 ft underlain by dense to very dense silty sand.

Borings/CPT Soundings Near The Buildings

LB-3 - - - -

17-B-2 - -10.5 to -20.5 - 1.6

LCPT-4 - -8.8 to -10.5 and -22.0 to -23.3 - 0.4

Borings/CPT Soundings at Wharf 311

18CPT-1B - -12 to -25 0.8 2.3

18CPT-1C - -12 to -25 1.2 3.0

18CPT-

1DE2

- - - 0.8

18CPT-2B +6 to -25 +6 to -25 10.7 12.6

18CPT-2C +6 to -20 +6 to -25 10.8 12.0

18CPT-2CD +6 to -20 +6 to -25 10.8 11.2

18LB-1 - - - -

18LB-2 +6 to -14 +6 to -25 8.9 9.5

Note:

1. Liquefiable zones and seismically induced settlement estimates under DE and MCEG events are approximately same as that under CLE event.

2. “-“ means either the factor of safety against liquefaction potential is greater than one or estimated seismically induced settlement is negligible.

Geotechnical & Earthquake Engineering

Two cross-sections (B-B’ and C-C’) were developed at the east and west ends of the existing wharf 311 to characterize the soil conditions for the design of the proposed mooring dolphins.

Locations of the sections are shown in Figure 2-9. Figures 2-12 and 2-13 present the subsurface conditions.

The subsurface at the location of east mooring dolphin consists of medium dense sandy fill up to approximate El. +5 ft MLLW underlain by silty sands with interbedded layers of silty clays up to elevation of -25 ft MLLW. Very dense sandy soils were encountered below EL. -25 ft MLLW. A thick layer of very hard clayey silt was identified between elevations of -60 ft to -75 ft MLLW.

At the west end of Wharf 311, i.e. location of west mooring dolphin, medium dense sand was encountered from ground surface down to El. +5 ft MLLW. The underlying layer consisted of medium stiff silty clays with thickness of up to 22 feet (El. -20 ft MLLW). Very stiff clayey silt with layers of dense sand was encountered from El. -20 ft to -30 ft MLLW. The materials below El. -30ft MLLW generally consist of very dense sands with isolated layers of very stiff to hard clays. Idealized soil parameters are provided in Table 2-3.

The ground water table at the project site is directly related to tidal fluctuations due to the close proximity to the shoreline. The groundwater elevation measured during the site-specific soil borings varied between approximate El. -3 ft MLLW and +3 ft MLLW. For design purposes, the groundwater level was assumed to be at approximate El. +5 ft MLLW. Design water table near the end of project life due to sea level rise was assumed at approximate El. +8.8 ft MLLW.

Table 2-3 Idealized Soil Profiles and Strength Parameters

Approx. Elevation (ft, MLLW)

Soil Type Total Unit

Weight (lb/ft3)

Static Parameters Seismic

Parameters

Friction Angle (deg)

Cohesion (psf)

Friction Angle (deg)

Undrai ned

/Residu al

Shear Strengt h (psf)

East Mole Pier Area

Ground Surface/Mudline to Bottom the Rock Dike

Quarry Run Material 130 42 200 42 200

Below Rock Dike to -8

Dense Sand 120 36 100 36 100

-9 to -15 Very Stiff Clay 120 - 3,000 - 3,000

-16 to -24 Dense Sand 120 36 100 36 100

-24 to -29 Very Stiff Clay 120 - 3,000 - 3,000

-29 to -34 Dense Sand 120 36 100 36 100

-34 to -39 Very Stiff Clay 120 - 3,000 - 3,000

Below -39 Very Dense Sand 125 38 100 38 100

Geotechnical & Earthquake Engineering

Table 2-3 Idealized Soil Profiles and Strength Parameters (Continued)

Approx. Elevation (ft, MLLW)

Soil Type Total Unit

Weight (lb/ft3)

Static Parameters Seismic

Parameters

Friction Angle (deg)

Cohesion (psf)

Friction Angle (deg)

Undrained /Residual

Shear Strength

(psf)

South West End of the Pier (Up to 300 ft from the South West End)

8 to 15 ft Thick Layer Below Mudline

Very Soft Harbor Bottom Sediments

110 - 200 - 200

Below top 8 to 15 ft to -60

Vey Loose Sand 120 30 100 - 200

Below -60 Very Dense Sand 125 38 100 38 100

Pier Area outside the East Mole and North East End of the Pier

5 to 3 ft Thick Layer Below Mudline

Very Soft Harbor Bottom Sediments

110 - 200 - 200

Below top 3 to 5 ft to -60

Dense Sand 120 36 100 36 100

Below -60 Very Dense Sand 125 38 100 38 100

East Mole Building Area

Ground Surface to -12 Dense Sand 120 36 100 36 100

-12 to -22 Medium Dense Sand 120 34 100 - 80-900

-22 to -27 Very Stiff Clay 120 - 3,000 - 3,000

-27 to -33 Dense Sand 120 36 100 36 100

-33 to -38 Very Stiff Clay 120 - 3,000 - 3,000

Below -39 Very Dense Sand 125 38 100 38 100

Geotechnical & Earthquake Engineering

Approx. Elevation (ft, MLLW)

Soil Type Total Unit

Weight (lb/ft3)

Static Parameters Seismic

Parameters

Friction Angle (deg)

Cohesion (psf)

Friction Angle (deg)

Undrained /Residual

Shear Strength

(psf)

Location of Wharf 311 East Mooring Dolphin

+11 to +5 Sandy Fill 120 30 0 30 0

+5 to -25 Sandy/Clayey Silt 100 30 100 - 80-350

-25 to -60 Dense Sand 120 36 0 36 0

-60 to -75 Very Stiff Silt/Clay 115 - 3,000 - 2,400

Below -60 Very Dense Sand 125 38 0 38 0

Location of Wharf 311 West Mooring Dolphin

+11 to +5 Sandy Fill 120 30 0 30 0

+5 to -20 Silty Clay 100 0 750 - 80-350

-20 to -30 Very Stiff Silt/Clay 115 0 3,000 0 2,400

Below -30 Very Dense Sand 125 38 0 38 0

Note: Above soil parameters were developed for design purposes and should not be used to design structures or equipment needed during construction.

Figure 2-1 Project No. 17-111 Date: 10-11-18

PROJECT

LOCATION

Source: Saucedo et al., 2003

EXPLANATION

Af Artificial fill Qpe Paralic estuarine deposits Qms Unconsolidated shelf sediment Qopa Old paralic deposits, sand Qp Pleistocene sedimentary deposits, undivided

Regional Geologic Map

500 1000 meters0 Qms

Qp

P-224 CAUSEWAY, BOAT CHANNEL, AND TURNING

BASIN & P-226 AMMUNITION PIER

Project No.: 17-111

REGIONAL FAULT MAP

Date: 10/11/18

Project Location

N

Source: SCEDC, 2018

FIGURE 2-2

2% Damping 5% Damping 10% Damping 15% Damping 20% Damping 25% Damping

0.030 0.192 0.192 0.192 0.192 0.192 0.192

0.050 0.260 0.245 0.236 0.231 0.228 0.225

0.075 0.380 0.317 0.277 0.254 0.237 0.2254

0.100 0.478 0.373 0.306 0.267 0.242 0.2258

0.200 0.648 0.480 0.370 0.305 0.259 0.2271

0.300 0.640 0.474 0.366 0.305 0.261 0.2285

0.400 0.628 0.469 0.361 0.305 0.262 0.2298

0.450 0.622 0.466 0.359 0.305 0.263 0.230

0.500 0.605 0.455 0.357 0.300 0.259 0.228

0.700 0.537 0.413 0.327 0.276 0.240 0.212

0.750 0.510 0.394 0.312 0.265 0.231 0.204

1.000 0.358 0.282 0.226 0.193 0.169 0.151

1.500 0.209 0.167 0.133 0.114 0.100 0.089

2.000 0.151 0.121 0.097 0.083 0.073 0.065

3.000 0.096 0.078 0.062 0.053 0.047 0.042

4.000 0.070 0.057 0.045 0.039 0.034 0.030

5.000 0.055 0.044 0.035 0.030 0.027 0.024

6.000 0.041 0.034 0.027 0.023 0.020 0.018

7.500 0.030 0.024 0.020 0.017 0.015 0.013

10.000 0.019 0.015 0.012 0.010 0.009 0.008

* Some spectral acceleration amplitudes were adjusted to provide a smooth ARS curve.

Date: 10-11-2018

Period

(sec)

EMI Project No: 17-111

OLE ARS* (g)

P-224 CAUSEWAY, BOAT CHANNEL, AND TURNING

BASIN & P-226 AMMUNITION PIER

NAVAL WEAPON STATION, SEAL BEACH, CALIFORNIA

Recommended Acceleration Response Spectra for

Operating Level Earthquake (OLE)

0.0

0.2

0.4

0.6

0.8

0.0 1.0 2.0 3.0 4.0 5.0

S p e c tr a l A c c e le ra ti o n g

Period (sec.)

2% Damping

5% Damping

10% Damping

15% Damping

20% Damping

25% Damping

Figure 2-3

0.030 0.432 0.432 0.432 0.432 0.432 0.432

0.050 0.545 0.512 0.495 0.485 0.477 0.471

0.075 0.741 0.617 0.540 0.495 0.481 0.468

0.100 0.931 0.727 0.596 0.520 0.485 0.466

0.200 1.249 0.926 0.713 0.588 0.500 0.454

0.300 1.225 0.907 0.699 0.577 0.490 0.442

0.400 1.180 0.880 0.687 0.573 0.493 0.431

0.450 1.157 0.867 0.678 0.568 0.490 0.429

0.500 1.135 0.853 0.670 0.562 0.486 0.427

0.700 1.039 0.799 0.631 0.533 0.463 0.409

0.750 1.017 0.786 0.622 0.527 0.459 0.407

1.000 0.912 0.718 0.574 0.490 0.431 0.385

1.150 0.839 0.664 0.531 0.453 0.398 0.356

1.500 0.605 0.484 0.388 0.331 0.291 0.259

2.000 0.394 0.318 0.254 0.217 0.191 0.170

3.000 0.250 0.203 0.162 0.139 0.122 0.109

4.000 0.183 0.149 0.119 0.102 0.089 0.080

5.000 0.149 0.121 0.097 0.083 0.073 0.065

6.000 0.120 0.098 0.078 0.067 0.059 0.052

7.500 0.091 0.074 0.059 0.051 0.045 0.040

10.000 0.059 0.048 0.038 0.033 0.029 0.026

* Some spectral acceleration amplitudes were adjusted to provide a smooth ARS curve.

EMI Project No: 17-111 Date: 10-11-2018

Period

(sec)

Design Earthquake ARS* (g)

Recommended Acceleration Response Spectra for

Contingency Level Earthquake (CLE)

P-224 CAUSEWAY, BOAT CHANNEL, AND TURNING

BASIN & P-226 AMMUNITION PIER

NAVAL WEAPON STATION, SEAL BEACH, CALIFORNIA

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

0.0 1.0 2.0 3.0 4.0 5.0

S p e c tr a l A c c e le ra ti o n g

Period (sec.)

2% Damping

5% Damping

10% Damping

15% Damping

20% Damping

Figure 2-4

0.030 0.491 0.491 0.491 0.491 0.491 0.491

0.050 0.623 0.585 0.566 0.554 0.545 0.539

0.075 0.834 0.695 0.608 0.557 0.546 0.535

0.100 1.028 0.803 0.658 0.574 0.547 0.531

0.200 1.375 1.019 0.784 0.647 0.550 0.517

0.300 1.377 1.020 0.785 0.648 0.551 0.502

0.400 1.323 0.988 0.770 0.643 0.553 0.488

0.450 1.297 0.971 0.760 0.636 0.549 0.481

0.500 1.270 0.955 0.750 0.630 0.544 0.478

0.700 1.118 0.860 0.679 0.574 0.499 0.441

0.750 1.083 0.836 0.663 0.561 0.489 0.433

1.000 0.940 0.740 0.592 0.506 0.444 0.396

1.500 0.692 0.553 0.443 0.378 0.332 0.296

2.000 0.527 0.425 0.340 0.290 0.255 0.228

3.000 0.348 0.283 0.227 0.193 0.170 0.152

4.000 0.253 0.205 0.164 0.140 0.123 0.110

5.000 0.206 0.167 0.134 0.114 0.100 0.090

6.000 0.166 0.135 0.108 0.092 0.081 0.072

7.500 0.127 0.103 0.082 0.070 0.062 0.055

10.000 0.085 0.069 0.055 0.047 0.042 0.037

* Some spectral acceleration amplitudes were adjusted to provide a smooth ARS curve.

Date: 10-11-2018

Period

(sec)

Design Earthquake ARS* (g)

EMI Project No: 17-111

Recommended Acceleration Response Spectra for

Design Earthquake (DE)

P-224 CAUSEWAY, BOAT CHANNEL, AND TURNING

BASIN & P-226 AMMUNITION PIER

NAVAL WEAPON STATION, SEAL BEACH, CALIFORNIA

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

0.0 1.0 2.0 3.0 4.0 5.0

S p e c tr a l A c c e le ra ti o n g

Period (sec.)

2% Damping

5% Damping

10% Damping

15% Damping

20% Damping

Figure 2-5

0.030 0.002 0.002 0.002 0.002 0.002 0.002

0.050 0.006 0.006 0.006 0.006 0.006 0.006

0.075 0.021 0.017 0.015 0.014 0.013 0.012

0.100 0.047 0.036 0.030 0.026 0.024 0.022

0.200 0.253 0.188 0.145 0.119 0.101 0.089

0.300 0.564 0.417 0.322 0.269 0.230 0.201

0.400 0.982 0.733 0.566 0.477 0.411 0.360

0.450 1.231 0.922 0.712 0.604 0.521 0.456

0.500 1.480 1.113 0.874 0.734 0.634 0.557

0.700 2.576 1.981 1.565 1.322 1.149 1.015

0.750 2.808 2.168 1.718 1.455 1.268 1.123

1.000 3.502 2.758 2.207 1.884 1.655 1.478

1.500 4.588 3.670 2.937 2.507 2.203 1.966

2.000 5.889 4.749 3.800 3.244 2.850 2.544

3.000 8.436 6.858 5.487 4.685 4.116 3.674

4.000 10.936 8.891 7.114 6.074 5.336 4.763

5.000 13.331 10.838 8.672 7.404 6.504 5.807

6.000 14.507 11.794 9.437 8.057 7.078 6.319

7.500 16.517 13.428 10.744 9.173 8.059 7.194

10.000 18.333 14.904 11.925 10.182 8.945 7.985

Date: 10-11-2018

Period

(sec)

EMI Project No: 17-111

OLE Relative Displacement Response Spectra (inch)

P-224 CAUSEWAY, BOAT CHANNEL, AND TURNING

BASIN & P-226 AMMUNITION PIER

NAVAL WEAPON STATION, SEAL BEACH, CALIFORNIA

Recommended Relative Displacement Spectra for

Operating Level Earthquake (OLE)

0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0

R e la ti v e

D is p la c e m e n t

(i n

Period (sec.)

2% Damping

5% Damping

10% Damping

15% Damping

20% Damping

Figure 2-6

0.030 0.004 0.004 0.004 0.004 0.004 0.004

0.050 0.013 0.013 0.012 0.012 0.012 0.012

0.075 0.041 0.034 0.030 0.027 0.026 0.026

0.100 0.091 0.071 0.058 0.051 0.047 0.046

0.200 0.489 0.362 0.279 0.230 0.196 0.178

0.300 1.078 0.799 0.615 0.507 0.431 0.389

0.400 1.846 1.377 1.074 0.897 0.771 0.674

0.450 2.291 1.716 1.343 1.125 0.970 0.850

0.500 2.774 2.086 1.637 1.375 1.189 1.044

0.700 4.978 3.829 3.025 2.554 2.221 1.962

0.750 5.596 4.322 3.424 2.900 2.528 2.239

1.000 8.917 7.021 5.618 4.796 4.214 3.762

1.150 10.851 8.585 6.869 5.865 5.152 4.599

1.500 13.323 10.658 8.528 7.281 6.396 5.710

2.000 15.406 12.424 9.940 8.487 7.456 6.656

3.000 21.977 17.868 14.296 12.206 10.723 9.573

4.000 28.697 23.331 18.667 15.938 14.001 12.499

5.000 36.479 29.657 23.729 20.260 17.798 15.889

6.000 42.331 34.415 27.536 23.510 20.653 18.438

7.500 50.302 40.895 32.720 27.937 24.542 21.910

10.000 57.319 46.600 37.285 31.834 27.966 24.966

EMI Project No: 17-111 Date: 10-11-2018

Period

(sec)

CLE Relative Displacement Response Spectra (inch)

Recommended Relative Displacement Spectra for

Contingency Level Earthquake (CLE)

P-224 CAUSEWAY, BOAT CHANNEL, AND TURNING

BASIN & P-226 AMMUNITION PIER

NAVAL WEAPON STATION, SEAL BEACH, CALIFORNIA

0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0

R e la ti v e

D is p la c e m e n t

(i n

Period (sec.)

2% Damping

5% Damping

10% Damping

15% Damping

20% Damping

Figure 2-7

0.030 0.004 0.004 0.004 0.004 0.004 0.004

0.050 0.015 0.014 0.014 0.014 0.013 0.013

0.075 0.046 0.038 0.033 0.031 0.030 0.029

0.100 0.100 0.079 0.064 0.056 0.053 0.052

0.200 0.538 0.398 0.307 0.253 0.215 0.202

0.300 1.212 0.898 0.691 0.570 0.485 0.442

0.400 2.071 1.545 1.205 1.006 0.865 0.764

0.450 2.568 1.924 1.505 1.260 1.087 0.952

0.500 3.105 2.335 1.833 1.539 1.331 1.169

0.700 5.357 4.121 3.255 2.749 2.390 2.111

0.750 5.956 4.599 3.645 3.086 2.690 2.383

1.000 9.190 7.237 5.790 4.944 4.343 3.877

1.500 15.220 12.176 9.742 8.318 7.307 6.523

2.000 20.605 16.616 13.294 11.351 9.972 8.902

3.000 30.662 24.928 19.945 17.029 14.960 13.355

4.000 39.534 32.141 25.716 21.956 19.289 17.220

5.000 50.358 40.940 32.757 27.968 24.570 21.934

6.000 58.410 47.487 37.995 32.440 28.498 25.441

7.500 69.627 56.606 45.291 38.669 33.971 30.327

10.000 83.258 67.688 54.158 46.240 40.622 36.264

Date: 10-11-2018

Period

(sec)

EMI Project No: 17-111

Design Earthquake Relative Displacement Response Spectra (inch)

Recommended Relative Displacement Spectra for

Design Earthquake (DE)

P-224 CAUSEWAY, BOAT CHANNEL, AND TURNING

BASIN & P-226 AMMUNITION PIER

NAVAL WEAPON STATION, SEAL BEACH, CALIFORNIA

0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0

R e la ti v e

D is p la c e m e n t

(i n

Period (sec.)

2% Damping

5% Damping

10% Damping

15% Damping

20% Damping

Figure 2-8

LB-4

LB-5

OB-1

OB-2

OB-3

OB-4

OB-5

OB-6

LCPT-1

LCPT-2

LCPT-5

CPT-1

CPT-2

CPT-3

CPT-4

CPT-5

CPT-6

CPT-7

CPT-8

CPT-9

CPT-10

CPT-11

CPT-12

CPT-13

400 200 0 400 Feet

SCALE

LEGEND

17-B-1

17-B-6

17-B-X

17-C-Y

17-C-6

A'

18CPT-2B, -2C,

-2CD, -2DE

18OB-5

18OB-6

18OB-3

18OB-2

18OB-1

18OB-4

Overland Boring (2018)18LB-1

Pavement Boring (2018)18PC-1

Overland Cone Penetration Test (2018)18CPT-1

18OB-1 Overwater Boring (2018)

18PC-1

18PC-3

18PC-4

18PC-6

B'

C

18PC-5

Earth Mechanics, Inc.

Geotechnical and Earthquake Engineering

FY19 MCON PROJECT P-224 CAUSEWAY, BOAT CHANNEL, AND TURNING BASIN & FY20

MCON PROJECT P-226 AMMUNITION PIER

Date: 10-11-2018EMI Project Number: 17-111

Locations of Sections and Site-specific Explorations Map

Figure 2-9

Proposed Wharf Proposed Truck Turnaround Area

-120

-110

-100

-90

-80

-70

-60

-50

-40

-30

-20

-10

0 5 10 15 20 25 30 35 40 45

FR,%

0 010 600.00

N or th in g qt, tsf

E as tin g

EL. -50.0'

FR,%

0 010 600.00

N or th in g qt, tsf

E as tin g

EL. -96.0'

FR,%

0 010 600.00

N or th in g qt, tsf

E as tin g

EL. -50.0'

FR,%

0 010 300.00

N or th in g qt, tsf

E as tin g

EL. -29.9'

EL. -111.5'

SM

SP

CL

ML

SP

CL

SM

SP-SM

CL

SM

SP-SM

18LB-1

E as tin g

N or th in g

E le va tio n (f t)

Project No.: 17-111 DATE: 10-11-18

Distance (ft)

P-224 CAUSEWAY, BOAT CHANNEL, AND TURNING

BASIN & P-226 AMMUNITION PIER

The number (XX) shown in the bore log is SPT equivalent N60 blow count.

Earth Mechanics, Inc.

Geotechnical and Earthquake Engineering

Cross Section B-B'

Figure 2-12

P O

R T

F E

N C

E

X

E

B

O R

IN

G

LO

G

S -2

8.

G P

J E

M I

C A

LT

R

A N

S

V 1.

0.

G

LB

/1

1/

18CPT-1B

EL. 10'

18CPT-1C

EL. 10'

18CPT-1DE2

EL. 10.0'

18CPT-1E

EL. 10.0'

EL. 10'

-120

-110

-100

-90

-80

-70

-60

-50

-40

-30

-20

-10

0 2 4 6 8 10 12 14 16 18 20

FR,%

0 010 500.00

N or th in g qt, tsf

E as tin g

EL. -78.9'

FR,%

0 010 500.00

N or th in g qt, tsf

E as tin g

EL. -49.0'

FR,%

0 010 500.00

N or th in g qt, tsf

E as tin g

EL. -49.0'

FR,%

0 010 500.00

N or th in g qt, tsf

E as tin g

EL. -9.0'

EL. -110.5'

SM

SP-SM

SC

SP-SM

ML

CL-ML

SM

SP-SM

SM

CL-ML

ML

CH

ML

SP-SM

ML

MH

CL

SM

SP-SM

18LB-2

E as tin g

N or th in g

E le va tio n (f t)

Project No.: 17-111 DATE: 10-11-18

Distance (ft)

P-224 CAUSEWAY, BOAT CHANNEL, AND TURNING

BASIN & P-226 AMMUNITION PIER

The number (XX) shown in the bore log is SPT equivalent N60 blow count.

Earth Mechanics, Inc.

Geotechnical and Earthquake Engineering

Cross Section C-C'

Figure 2-13

P O

R T

F E

N C

E

X

E

B

O R

IN

G

LO

G

S -2

8.

G P

J E

M I

C A

LT

R

A N

S

V 1.

0.

G

LB

/1

1/

18CPT-2B

EL. 11.0'

18CPT-2C

EL. 11.0'

18CPT-2CD

EL. 11.0'

18CPT-2DE

EL. 11.0'

EL. 11.0'

Geotechnical & Earthquake Engineering

3.0 ANALYSES, CONCLUSIONS AND RECOMMENDATIONS

3.1 Seismically Induced Settlements

Liquefaction potential and seismically induced settlement of the project site were evaluated following simplified procedures and the results are provided in Section 2.4 of the report. Based on the evaluation, the liquefaction potential of the soils in the vicinity of the proposed P-226 Pier is expected to be very low. Only a few small isolated pockets of granular materials are expected to liquefy under the three levels of earthquakes.

Near the southwest end of the pier, due to the presence of very loose granular materials, up to 4 inches of seismically induced settlement is expected. No seismically induced settlement is expected in the mole area near the Pier. However, in the vicinity of proposed building locations, seismically induced settlement is estimated to be about 2 inches. Differential settlement due to liquefaction is expected to be about 1 inch in the vicinity of the building. It is our understanding that the proposed truck turnaround area and the causeway will be constructed using granular fill.

These granular fill materials are anticipated to be loose to medium dense state after the construction and are potentially liquefiable and settle during seismic events. Seismically induced settlement up to 18 inches can be anticipated depending on the thickness of the new fill. Based on the calculations, liquefaction potential of subsurface materials and seismically induced settlement estimates under DE and MCEG events are approximately similar to CLE event.

The liquefaction potential of the soils at Wharf 311 is expected to be high. The existing silts and silty sands above El. -25 ft MLLW are highly liquefiable with estimated seismic settlement of up to 13 inches. The settlement at the location of the proposed west dolphin, i.e., west end of the wharf; is anticipated to be relatively less due to presence of non-liquefiable clayey soils. The seismic settlement at this particular location is estimated to be up to 1 inch during OLE and up to 3 inches during CLE events.

3.2 Slope Stability Analyses and Recommendations

Slope stability evaluations under existing conditions were performed using the idealized soil parameters provided in Table 2-3 and using cross sections developed based on the proposed slope configuration provided by the designers. Static, post-earthquake and pseudo-static (seismic) global stability analyses were performed using the computer program SLIDE 6.0 (Rocscience, 2010). The evaluations are based upon limiting equilibrium of circular failure modes and sliding block failure modes using Spencer’s method (Spencer, 1967). Spencer’s method assumes the inter-slice forces to be constant and rigorously satisfies the static equilibrium. Results of slope stability analyses for existing conditions are summarized in Table 3-1. The output files from slope stability analyses are provided in Appendix B.

For slopes under static conditions, factor of safety against failure under static conditions were estimated to be more than 1.5 which is generally considered acceptable in geotechnical engineering practice (NAVFAC, 1986a).

The post-earthquake stability immediately after a seismic event was estimated, generally, using residual shear strengths. Shear strength of the very soft to soft fine-grained layer was reduced to 80% of the undrained shear strength to account for potential cyclic degradation of very soft to soft fine-grained materials under earthquake loading. The factors of safety after design

Geotechnical & Earthquake Engineering earthquake conditions are estimated to be greater than 1.1 for the existing slope configurations at project site. Therefore, uncontrolled slope displacement (flow slide) is not expected.

3.2.1 Breakwater Stability

During Construction: Stability of the breakwater dike during construction was evaluated. Based on the information provided by the engineers, we understand that the proposed breakwater construction is expected to take more than 7 months. Our evaluation indicates that the anticipated construction duration would allow the weak clay materials below the breakwater dike to gain strength and provide the necessary support to the breakwater dike. The duration of construction is also expected to reduce the post-construction settlements and lateral deformations of the breakwater as well as reduce the loading on the mooring dolphin piles due to dike deformations.

Long Term Static Stability: Our evaluations indicate that the long term static stability of the break water is not a concern, since the estimated slope stability factor of safety (FOS) is more than 1.5, a value that is considered acceptable.

During Seismic Condition: Post-earthquake FOS is estimated to be more than 1.1 (the minimum value required by UFC 4-152-01 and ASCE 61-14); therefore, no flow slide type failure of the breakwater is expected. However, the breakwater is expected to undergo slope displacements under OLE, CLE and DE. However, the sixteen 24-inch octagonal concrete piles supporting the southwest mooring dolphin are expected to “pin” the slope thus reducing the deformations significantly. Based on detailed pinning analysis (see Appendix B), estimated slope displacements with pile pinning effects are 1”, 5” and 7.5”, respectively under OLE, CLE and DE. Based on our discussions with the structural designers, pile shears developed due to the estimated slope movements are within the strain limits allowed in ASCE 61-14.

3.2.2 Causeway Stability during Construction

Similar to the breakwater dike, the proposed causeway will be constructed in lifts of 10ft height and each lift will take more than one month to be completed. This will result in minimum construction duration of 4 months for the completion of the causeway construction. Our preliminary evaluation indicates that the anticipated construction duration would allow the weak clay materials below the causeway dike to gain strength and provide the necessary support to the causeway.

There is no design concern regarding the long-term static and seismic stability of the causeway and slope stability results are included in Appendix B.

3.2.3 Truck Turnaround Area Stability during Construction

Since the truck turnaround area site has less than 5 ft thick harbor bottom sediments and the perimeter dikes include a 30 ft wide rock key, there is no stability concern during construction.

The long-term static and seismic stability of the truck turnaround area dikes are not a concern and slope stability results are included in Appendix B.

Slope displacements were estimated using Newmark sliding block analysis procedure described by Transportation Research Board (TRB, 2008). Free-field slope displacements (i.e., without considering the pinning effects of pier piles) estimated using the Newmark sliding block analysis procedure are tabulated in Table 3-1.

Geotechnical & Earthquake Engineering

Table 3-1 Results of Slope Stability Analyses

Section

Factor of Safety Yield

Accelera tion (g)

Slope Displacement /Lateral Spread Estimate

(inch) Static Condition

Post- Earthquake1

OLE CLE DE

East Mole – Pier Area 2.6 2.7 0.32 < 2 < 2 < 2

East Mole – Building Area 1.9 1.6 0.15 < 2 6 10

Truck Turnaround Area – Pier Side

1.8 1.6 0.11 < 2 12 18

Truck Turnaround Area – Back Side

1.8 1.4 0.07 2 24 35

Causeway 1.5 1.1 0.03 8 52 74

West Mole – Dredge Slope

2.4 2.5 0.32 < 2 < 2 < 2

1 Post-Earthquake factor of safety is same for OLE and CLE earthquake events.

2 Yield acceleration is same for OLE and CLE earthquake events.

The estimated lateral dike displacements within the proposed truck turnaround area with a 30 ft wide key under the OLE, CLE and DE events are approximately 2, 12, and 18 inches, respectively. These lateral displacements are within the recommended screening displacements per Port of Long Beach (POLB) Wharf Design Criteria (WDC) (POLB, 2015). Per the POLB WDC, when the lateral dike displacements are within the screening limits, no additional analysis is needed with respect to kinematic loading on 24-inch octagonal concrete piles supporting the wharf.

Existing Mole area adjacent to the Truck Turnaround area is proposed to be dredged and rock protection layer will be placed. Due to the presence of dense and hard subsurface materials, slope displacement in this area is expected to be better than the slope displacements within the Truck Turnaround area. Therefore, kinematic loading on 24-inch octagonal concrete piles supporting the wharf is not a design issue.

3.2.4 Jetties at Public Navigation Channel (PNC)

The proposed public navigation channel slopes will be dredged no steeper than 2.5H:1V and will be dressed with quarry rock and armor stones. The slope stability factor of safety (FOS) for a 2.5H:1V slope is anticipated to be equal to or greater than 1.5 under static loading conditions.

There is no seismic design requirements prescribed for the jetties at this stage.

3.3 Ammunition Pier Piles

Per structural designers, the proposed Ammunition Pier will be supported on vertical 24-inch octagonal, precast prestressed (PCPS) concrete piles with varying center to center spacing of 8 ft to 20 ft. Axial and lateral pile capacities and construction considerations for the 24 inch octagonal PCPS concrete piles are provided below.

Geotechnical & Earthquake Engineering

3.3.1 Axial Capacity Recommendation for Ammunition Pier Piles

Pile configuration for the proposed Ammunition Pier per structural designers is shown in Figure 3-1. Under static conditions, piles located outside the East Mole area with 20 ft by 20 ft spacing and piles located within the East Mole area with spacing of 8 ft by 8 ft are expected to carry maximum compressive loading of 480 kips and 250 kips, respectively. Tensile demand on the Pier piles under static conditions is insignificant.

Under seismic conditions, piles located outside the East Mole Area with 20 ft by 20 ft spacing are expected to carry maximum compressive loading of 355 kips while the tensile demand on these piles is insignificant. Under seismic conditions, piles located within the East Mole area with a spacing of 8 ft by 8 ft are expected to carry maximum compressive loading of 360 kips while the maximum tensile demand on some of these piles is 124 kips without considering the…