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CENA H and V SITE AMPLIFICATION

Walter Silva

Pacific Engineering and Analysis

October 1, 2009

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• NGA-E Horizontal Component

- Conditional on VS(30m), is Amplification for

WNA Similar to CENA Across Loading

Levels?

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• Issues: Similarities in

– Profiles

• Velocities

–VS (30m) ≈ 180m/sec to 2,000m/sec

–Basement VS

»WNA ≈ 3,000 ft/sec

»CENA ≈ 6,000 ft/sec

»CENA Reference ≈ 9,300 ft/sec

»Impact Shallow Profiles ≤ 500 ft

»Impact Depth to 1 km/sec

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• Damping (kappa)– WNA, 0.04 sec, 5 Hz Peak

• Large Contribution of Bedrock ≈ 0.04 sec –Total kappa Varies Little With Soil Depth

– CENA 0.04 SEC, 5 Hz peak Deep Profile > 3,000 ft• Bedrock 0.006 sec, 1,000 ft Soil 0.01 sec• Large Impact on Shallow Profiles at Low Loading Levels

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• Nonlinear Dynamic Material Properties- WNA, Peninsular Range Curves- CENA Curves

- Daniel Is, SC- Savannah River, G- Grand Gulf, M- Riverbend, M- ORNL, T- ?

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• Differences in Control Motion

- Bedrock Kappa

- WNA 0.04 sec, 5 Hz

- CENA

- Precambrian 0.006 sec, 20 Hz

- Sedimentary 0.02 to 0.04 sec,

10 Hz to 5 Hz

- Relatively Higher Loading at High

Frequency, Conditional on PGA

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• Site/Region Specific Hazard

– ≈ 35 NPP

– ≈ 100 projects

– DOE Sites

• Savannah River

• ORNL• Paducah

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• Project Areas

– New Jersey, Virginia, Carolinas, Georgia, Tennessee, Indiana, Missouri, Oklahoma

• Project Regions

– Central US, NYC, South Carolina

• Profiles Sampled

– Soft to Firm Soil Overlying Hard and Soft Rock

• Soil Depths 20 ft to 10,000 ft

– Soft to Firm Rock

• Several Hundred Feet to Thousands of Feet Over Hard Rock

• Profile Database

– Several Hundred CENA Profiles

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• Available Analyses Suggest Deep Soil Response WNA ≈ CENA Across Loading Level

- Relatively straightforward

- Check/Confirm with Specific Cases

• Savannah River

- Very Stiff Soil

- Over Hard Rock (Crystalline)

- Over Soft Rock (Dumbarton Basin)

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• Southern Coastal Plain

- Charleston

- Cooper Marl• Piedmont

- Residual Soil Saprolite• Southern Miss Embayment

• Uplands, Grand Gulf

- Till

- Deep Stiff Soil• Lowlands, Riverbend

- Deep Soft Soil

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• Issues to Resolve

– Shallow Soil < 3,000 ft

• Appropriate Total Kappa Constraint

–Affects Low Loading Levels

– Soft - Firm Rock Over Hard Rock

• ≤ 1 km Rock

–Appropriate Profile

–Appropriate kappa

»Piedmont, Saprolite

• ≥ 1 km Rock

–Characteristics of WNA Soft/Firm Rock

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• Data Requirements:

– Relative Site Response

– Kappa Inversions

• Shallow Soil (< 3,000 ft)

• Soft Rock

– Shear-wave Velocities

• Recording Sites, at a Minimum VS(30m)

• Reference Site and Shallow Soil Sites

– > VS to at Least 100m

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• Verticals

– Hard Rock H only or H, V GMPEs

• Issues

– Need CENA Relative Site Response For V

– Empirical CENA H/V Ratios

• Small Magnitude/Large Distance

–Rock: 1.1 at 1 Hz, 1.5 at 10 Hz

–Soil 1.5 at 1 Hz, 1.7 at 5 Hz

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• Look at Close Distance V/H Ratios

–WNA Hard Rock

–CENA

»Nahanni

»Gazli

»New Brunswick

»Goodnow

»Monticello

»New Hampshire

»Enola, Arkansas

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– V Site Response Analysis

• Incident Inclined P-SV

• Nonlinear Constrained Modulus

• Uncoupled H and V Components?

– NGAE Specifies H Hard Rock Only

• Develop Site Specific H Hazard

• Develop Site Specific Fully Probabilistic V Hazard

–Distribution of V/H Ratios

»Duke

»Grand Gulf

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Profile Comparison

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– Site Response Analysis

• Incident Inclined P-SV

• Nonlinear Constrained Modulus

• Uncoupled H and V?

– NGAE H Hard Rock Only

• Develop Site Specific H Hazard

• Develop Specific Fully

• Probabilistic V Hazard

–Distribution V/H Ratios

»Duke

»Grand Gulf

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Amplification M1P1

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Amplification M1P1(Cont.)

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Amplification

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Amplification(Cont.)

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Mean Centered NEHRP Profiles

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NEHRP AmplificationCategory C, WUS,

CEUS

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NEHRP AmplificationCategory D, WUS,

CEUS

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NEHRP AmplificationCategory E, WUS, CEUS

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Shear Wave Velocity Profiles

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Shear Wave Velocity Profiles(cont.)

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Profile Categories, Depth Bins, & Classes

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Profile kappa values from small strain damping over maximum

profile mean depth

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Comparison of UHS

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EPRI 28 Nuclear Plant Sites

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PGA 6-Sigma Rock Hazards

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Weight Summary

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Historic and Instrumental Seismicity

for the SEUS

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