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CENA H and V SITE AMPLIFICATION. Walter Silva Pacific Engineering and Analysis October 1, 2009. NGA-E Horizontal Component - Conditional on V S (30m), is Amplification for WNA Similar to CENA Across Loading Levels?. Issues: Similarities in Profiles Velocities
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CENA H and V SITE AMPLIFICATION Walter Silva Pacific Engineering and Analysis October 1, 2009
NGA-E Horizontal Component - Conditional on VS(30m), is Amplification for WNA Similar to CENA Across Loading Levels?
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
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
Nonlinear Dynamic Material Properties - WNA, Peninsular Range Curves - CENA Curves - Daniel Is, SC - Savannah River, G - Grand Gulf, M - Riverbend, M - ORNL, T - ?
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
Site/Region Specific Hazard • ≈ 35 NPP • ≈ 100 projects • DOE Sites • Savannah River • ORNL • Paducah
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
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)
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
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
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
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
Look at Close Distance V/H Ratios • WNA Hard Rock • CENA • Nahanni • Gazli • New Brunswick • Goodnow • Monticello • New Hampshire • Enola, Arkansas
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
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
Profile kappa values from small strain damping over maximum profile mean depth