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Performance-Based Geotechnical Earthquake Engineering for Seismic Design Prediction

Explore critical aspects of geotechnical earthquake engineering to predict seismic displacements and minimize damage. From slope models to intensity measures, learn techniques for efficient and reliable seismic design.

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Performance-Based Geotechnical Earthquake Engineering for Seismic Design Prediction

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  1. NEEDS FOR PERFORMANCE-BASED GEOTECHNICAL EARTHQUAKE ENGINEERING Jonathan Bray University of California, Berkeley Pacific Earthquake Engineering Research Center

  2. SHAKING-INDUCED DAMAGE to Bridges and Buildings Moehle

  3. Seismic Displacement LIQUEFACTION-INDUCED DAMAGE EERC Slide Collection EERC Slide Collection

  4. P E E R Framework for Performance-Based Engineering DV = Decision variable (e.g., down-time, costs)DM = Damage Measure (e.g. damage state, cracking)EDP = Engineering Demand Parameter (e.g., peak story drift, drift ratio, seismic displacement)IM = Intensity measure (e.g., Sa, Arias intensity)(IM) = Rate of exceedance of IM {Loss analysis}{Damage analysis}{Dynamic analysis}{Hazard analysis}

  5. D IM IM: characterizes the strong ground motion M, R, Site, Fault Example Objective: predict seismic Displacements Decouple the HAZARD analysis from the DYNAMIC RESPONSE Minimize the dispersion around the predicted displacements

  6. 1.SLOPE MODEL equiv-linear, SDOF, coupled stiffness (Ts) - strength (ky) 2. EARTHQUAKE DATABASE 45 EQ - 1447 records Ts ky D 3. INTENSITY MEASURES amplitude: PGA, PGV, PGD, SA, SV frequency content: Tp, Tm duration: D5_95, Dbracketed other: Arias Intensity Housner Spectral Intensity EXAMPLE

  7. EFFICIENCY STIFF SLOPE

  8. EFFICIENCY RESULTS STIFF SLOPEDUCTILE SLOPE Ts < 0.5 s Ts > 0.5 s Period IndependentArias IntensitySpectral Intensity Period Dependent Spectral Acceleration at Ts

  9. SHORT BUILDING OR BRIDGE • Intensity Measures (IM): • Sa(T1), PGV, Ia, Sa(T1)[Sa(2T1)/Sa(T1)]0.5 Longitudinal drift ratio Longitudinal drift ratio (Mackie and Stojadinovic, 2002)

  10. ln(D) = f(IM) + d M+e ln(R) SUFFICIENCY Stiff Slope NO INTENSITY MEASURE IS SUFFICIENT FOR ALL TS and ky

  11. VECTORS OF IM’s: D = f( SA(Ts), IM2) MORE DUCTILE STRONGER

  12. PERIOD-INDEPENDENT INTENSITY MEASURES Peak Ground Acceleration PGA Peak Ground Displacement PGD Arias Intensity (Arias, 1970) Cumulative Absolute Velocity (Kramer 2002; 5 cm/sec2 threshold) Response Spectrum Intensity (Housner, 1959) Peak Ground Velocity PGV & Pulse Period Tv

  13. PERIOD-DEPENDENT INTENSITY MEASURES Spectral Acceleration at Fundamental Period Spectral Combination (Cordova et al. 2000) Spectral Vector (Conte, 2002) Spectral Combination IM1I&2E (Luco and Cornell, 2001) Sa(T1) Sa(T1)

  14. Factors Affecting (IM): •  (m): Rate of earthquakes with magnitude m • f(m): relative likelihood of earthquakes with different magnitudes • f(IM|m,r): distribution of IM conditioned on m and r Stewart et al. PEER Report-2001/09

  15. Source Characterization • Source locations • Segmentation • m-A relations • f(m) models • Rate • Large events (characteristic) • Small events Source: WGCEP, 1999

  16. SURFACE FAULT RUPTURE

  17. Seismic Site Effects • Local ground conditions • Response of horizontal sediment layers • Accounts for resonance, impedance contrasts, soil non-linearity • Basin response • Accounts for 2-D/3-D sediment geometry • Surface topographic effects Combined Influence on Ground Motions

  18. Simplified Geotechnical Site (SGS) Categories (Rodríguez-Marek et al. 2001)

  19. Northridge EQ Loma Prieta T = 0.3 s T = 1.0 s T = 0.3 s T = 1.0 s Site SGS UBC SGS UBC SGS UBC SGS UBC B .40 (.08) .46 (.07) .45 (.11) .52 (.09) .51 (.10) .52 (.10) .58 (.11) .61 (.11) C .54 (.05) .54 (.06) .60 (.05) .54 (.06) .38 (.05) .36 (.05) .53 (.08) .52 (.07) D .41 (.04) .42 (.03) .36 (.03) .41 (.03) .39 (.07) .39 (.06) .59 (.11) .64 (.10)

  20. 10 17 17 31 GROUND MOTION DATABASE Simplified Geotechnical System Rodriguez-Marek et al. 2001 Rock 15% Soft Rock / Stiff Shallow Soil Deep Stiff Soil 27% 58% Fault Types Reverse Oblique Normal 1208 records from 75 Earthquakes Active Plate Margins Magnitudes 4.7 – 7.6 Distances 0.1 – 250 km Reverse Strike Slip

  21. Near Fault Ground MotionsNorthridge EQ: Rinaldi Receiving Station Newhall - Pico Canyon

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