Oregon LNG Terminal Design Criteria

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Fina l Repor t

Marine Facilities Design Criteria,Oregon LNG Terminal

Prepared for

LNG Development Company, LLC(d/b/a Oregon LNG)

January 2008

Revised October 2008

Prepared by



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Contents

1.0 Introduction..........................................................................................................................1

2.0 Structural Loading...............................................................................................................1 2.1 Dead Loads .................................................................................................................1 2.2 Live Loads...................................................................................................................1 2.3 Earthquake Loads ......................................................................................................1 2.4 Mooring Loads ...........................................................................................................3 2.5 Berthing Loads ...........................................................................................................5 2.6 Wind and Current Loads on Structures..................................................................5 2.7 Load Combinations ...................................................................................................5

3.0 Mooring Lines and Hardware Safety Factors and Allowable Loads ...........................5

4.0 Seismic Analysis...................................................................................................................5

5.0 Mooring and Berthing Analysis ........................................................................................5

6.0 Geotechnical Hazards and Foundations ..........................................................................5 6.1 Liquefaction ................................................................................................................5 6.2 Slope Stability.............................................................................................................6 6.3 Seismic Slope Displacements ...................................................................................6

7.0 Structural Analysis and Component Design...................................................................6

Tables

1 Mooring Loads—Wind Speed in Knots (30-Second Gust).................................................. 32 Wind Speed Return Period Data (30-Second Gust).............................................................. 33 Thickness of Liquefiable Material and Post-Liquefaction Settlement ............................... 6

Figures

1 Design Earthquake 5% Damped Response Spectrum (MOTEMS Level 1) ...................... 22 Maximum Considered Earthquake 5% Damped Response Spectrum

(MOTEMS Level 2).................................................................................................................... 23 Maximum Tsunami Water Surface Elevations .....................................................................4



MARINE FACILITIES DESIGN CRITERIA, OREGON LNG TERMINAL

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1.0 IntroductionThis report is intended to document the basic design criteria used for preliminary design ofthe marine facilities at the Oregon Liquefied Natural Gas (LNG) Terminal. Specifically, themarine facilities include the following structures:

• An unloading platform• Four breasting dolphins• Six mooring dolphins• An LNG trestle• Interconnecting walkways

To the extent practical, the marine facilities preliminary design has been performed inaccordance with the 2005 Marine Oil Terminal Engineering and Maintenance Standards(MOTEMS), as published by the California State Lands Commission and available at thefollowing Web address:

http://www.slc.ca.gov/Division_Pages/MFD/MOTEMS/MOTEMS_Home_Page.html

2.0 Structural Loading

2.1 Dead LoadsSee MOTEMS Section 3103F.2.

2.2 Live Loads• Equipment and piping area loads: MOTEMS Table 31F-3-2.

• Uniform traffic load—areas available for vehicle access: 50 pounds per square foot (psf)(applied so as to achieve maximum stress in considered member).

• Truck loads: American Association of State Highway and Transportation Officials(AASHTO) H15 Truck.

• Walkways between dolphins: 50 psf or a single 300 pound concentrated load (appliedso as to achieve maximum stress in considered member).

• Unloading Platform Walkways and Elevated Platforms: 60 psf (applied so as to achievemaximum stress in considered member).

2.3 Earthquake LoadsMOTEMS Section 3103F.4 with a site-specific probabilistic seismic hazard analysis (PSHA).See Figures 1 and 2 for design response spectra.




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FIGURE 1Design Earthquake 5% Damped Response Spectrum (MOTEMS Level 1)

FIGURE 2Maximum Considered Earthquake 5% Damped Response Spectrum (MOTEMS Level 2)




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2.4 Mooring LoadsSee MOTEMS Section 3103F.5.

2.4.1 Wind Speed

TABLE 1Mooring Loads—Wind Speed in Knots (30-Second Gust)

Current = 0 kt a Current = 1 kt 1 Current = 3 kt 1 Current = 5 kt 1

Operating Condition 60 60 60 55

Survival Condition 70 70 65 60

a Current direction within 10 degrees of berthing line.

TABLE 2Wind Speed Return Period Data (30-Second Gust)

Return Period (Years) Wind Speed (Knots)

2 45.0

5 49.4

10 52.4

15 54.1

20 55.2

25 56.1

30 56.9

40 58.050 58.9

75 60.5

100 61.7

2.4.2 Current SpeedAdequate current speed data are not available for the Terminal location. Chapter 10,Columbia River, Oregon and Washington, in United States Coast Pilot 7, Pacific Coast:California, Oregon, Washington, Hawaii, and Pacific Islands, 2007 Edition, published by the

National Oceanic and Atmospheric Administration (NOAA), the U.S. Department ofCommerce, and the National Ocean Service, indicates that currents vary from 1 to 3 knots inthe vicinity of the Terminal. For preliminary design, a maximum 5-knot flood or ebb currentwith a direction within 10 degrees of the berthing line was assumed.

It is important to note that additional current speed and direction data will be required forfinal design of the Terminal.




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2.4.3 Wave ForcesWaves are not considered to be significant at the Terminal’s relatively sheltered location.Therefore, wave forces have not been analyzed and are not included in these design criteria.

2.4.4 Seiche

Long-period wave energy is negligible at the Terminal location; therefore, seiche effectshave not been analyzed and are not included in these design criteria.

2.4.5 TsunamiThe lowest elevation of all superstructure elements has been placed at an elevation abovethe design tsunami run-up elevation. As such, inundation and “slamming” effects areavoided. Steel cylinder piles have been designed to resist current speeds associated with atsunami effect. The presence of significant floating debris is considered to be unlikely;therefore, debris effects have not been analyzed and are not included in these designcriteria.

The maximum current speed during a tsunami event, based on site-specific hydrodynamicmodeling, has been determined to be 4.2 knots. This current speed is less than the designcurrent speed; therefore, tsunami effects are not required as part of the mooring analysis.

FIGURE 3Maximum Tsunami Water Surface Elevations




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2.5 Berthing LoadsSee MOTEMS Section 3103F.6.

2.6 Wind and Current Loads on StructuresSee MOTEMS Section 3103F.7.

2.7 Load CombinationsSee MOTEMS Section 3103F.8.

3.0 Mooring Lines and Hardware Safety Factors and AllowableLoadsSee MOTEMS Sections 3103F.9 and 3103F.10.

4.0 Seismic AnalysisSee MOTEMS Section 3104F, except for seismic loading (see Section 2.3).

5.0 Mooring and Berthing AnalysisSee MOTEMS Section 3105F, high risk classification.

6.0 Geotechnical Hazards and FoundationsThe marine facilities site lies within an area characterized by alluvial soil that may be subject

to liquefaction, seismic slope instability, and lateral spreading during and immediately afterstrong ground shaking. This section provides a summary of these hazards and how theyhave been mitigated for in the preliminary design. Additional details are provided inAppendix J.1 to Resource Report 13, Geotechnical Investigation Report for the Oregon LNGTerminal Project, dated October, 2008.

6.1 LiquefactionPotentially liquefiable soil layers have been identified as part of the project geotechnicalstudy as shown in Table 3.




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TABLE 3 Thickness of Liquefiable Material and Post-Liquefaction Settlement

Layer Thickness of Liquefiable Material(feet)

Estimated Post-LiquefactionSettlement (inches)

Ground Surface to Elevation -12 0 to 15 1 to 4

Elevation -12 to -80 5 to 15 1 to 4


Elevation -100 to -110 5 to 10 < 1


Elevation -120 to -150 20 to 30 < 1

Total 25 to 90 6 to 20

Vertical load carrying capacities for the marine facilities were calculated including theeffects of liquefaction.

6.2 Slope StabilityCut slopes have been designed with a minimum factor of safety of 2.0 under non-seismicconditions. Existing slopes at the location of the marine facilities have been analyzed and thefactor of safety is in excess of 2.0.

6.3 Seismic Slope DisplacementsThe site is vulnerable to seismic slope displacements during the MCE seismic event, with anestimated slope displacement of 9 inches from the ground surface to an approximate

elevation of -60 feet. The marine facilities foundations are designed to displace with theslope without collapse.

7.0 Structural Analysis and Component DesignSee MOTEMS Section 3107F.

Oregon LNG Terminal Design Criteria

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