NEEDS FOR PERFORMANCE-BASED GEOTECHNICAL EARTHQUAKE ENGINEERING Jonathan Bray University of...

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

Transcript of NEEDS FOR PERFORMANCE-BASED GEOTECHNICAL EARTHQUAKE ENGINEERING Jonathan Bray University of...

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

NEEDS FOR PERFORMANCE-BASED

GEOTECHNICAL EARTHQUAKE ENGINEERING

Jonathan Bray

University of California, Berkeley

Pacific Earthquake Engineering Research Center

Page 2: NEEDS FOR PERFORMANCE-BASED GEOTECHNICAL EARTHQUAKE ENGINEERING Jonathan Bray University of California, Berkeley Pacific Earthquake Engineering Research.

SHAKING-INDUCED DAMAGE to Bridges and Buildings

Moehle

Page 3: NEEDS FOR PERFORMANCE-BASED GEOTECHNICAL EARTHQUAKE ENGINEERING Jonathan Bray University of California, Berkeley Pacific Earthquake Engineering Research.

EERC Slide Collection

Seismic Displacement

LIQUEFACTION-INDUCED DAMAGE

EERC Slide Collection

Page 4: NEEDS FOR PERFORMANCE-BASED GEOTECHNICAL EARTHQUAKE ENGINEERING Jonathan Bray University of California, Berkeley Pacific Earthquake Engineering Research.

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

dIMdEDPdDMIMIMEDPpEDPDMpDMDVpDV ][]/[]/[]/[

Framework for Performance-Based EngineeringPPEEEERR

{Loss analysis}{Damage analysis}{Dynamic analysis}{Hazard analysis}

Page 5: NEEDS FOR PERFORMANCE-BASED GEOTECHNICAL EARTHQUAKE ENGINEERING Jonathan Bray University of California, Berkeley Pacific Earthquake Engineering Research.

D

M, R, Site, Fault

Decouple the HAZARD analysis from the DYNAMIC RESPONSE

Minimize the dispersion around the predicted displacements

Example Objective: predict seismic Displacements

IM

IM: characterizes the strong ground motion

Page 6: NEEDS FOR PERFORMANCE-BASED GEOTECHNICAL EARTHQUAKE ENGINEERING Jonathan Bray University of California, Berkeley Pacific Earthquake Engineering Research.

3. INTENSITY MEASURES amplitude: PGA, PGV, PGD, SA, SV frequency content: Tp, Tm

duration: D5_95, Dbracketed

other: Arias Intensity Housner Spectral Intensity

EXAMPLE1. SLOPE MODEL equiv-linear, SDOF, coupled stiffness (Ts) - strength (ky)

Ts

kyD

2. EARTHQUAKE DATABASE 45 EQ - 1447 records

Page 7: NEEDS FOR PERFORMANCE-BASED GEOTECHNICAL EARTHQUAKE ENGINEERING Jonathan Bray University of California, Berkeley Pacific Earthquake Engineering Research.

EFFICIENCYSTIFF SLOPE

Page 8: NEEDS FOR PERFORMANCE-BASED GEOTECHNICAL EARTHQUAKE ENGINEERING Jonathan Bray University of California, Berkeley Pacific Earthquake Engineering Research.

EFFICIENCY RESULTS

Period Independent Arias Intensity Spectral Intensity Period Dependent Spectral Acceleration at Ts

STIFF SLOPE DUCTILE SLOPE

Ts < 0.5 s Ts > 0.5 s

Page 9: NEEDS FOR PERFORMANCE-BASED GEOTECHNICAL EARTHQUAKE ENGINEERING Jonathan Bray University of California, Berkeley Pacific Earthquake Engineering Research.

Longitudinal drift ratio

Longitudinal drift ratio(Mackie and Stojadinovic,

2002)

SHORT BUILDING OR BRIDGEIntensity Measures (IM):

Sa(T1), PGV, Ia, Sa(T1)[Sa(2T1)/Sa(T1)]0.5

Page 10: NEEDS FOR PERFORMANCE-BASED GEOTECHNICAL EARTHQUAKE ENGINEERING Jonathan Bray University of California, Berkeley Pacific Earthquake Engineering Research.

)ln( aI

RN

DC

FfFf

SMssSMss

hRcMcMcc

21

22211211

224321

))6(())6((

)ln()6/ln()6(

Page 11: NEEDS FOR PERFORMANCE-BASED GEOTECHNICAL EARTHQUAKE ENGINEERING Jonathan Bray University of California, Berkeley Pacific Earthquake Engineering Research.

SUFFICIENCY ln(D) = f(IM) + d M+e ln(R)

NO INTENSITY MEASURE IS SUFFICIENT FOR ALL TS and ky

Stiff Slope

Page 12: NEEDS FOR PERFORMANCE-BASED GEOTECHNICAL EARTHQUAKE ENGINEERING Jonathan Bray University of California, Berkeley Pacific Earthquake Engineering Research.

VECTORS OF IM’s: D = f( SA(Ts), IM2)

STRONGER

MORE DUCTILE

Page 13: NEEDS FOR PERFORMANCE-BASED GEOTECHNICAL EARTHQUAKE ENGINEERING Jonathan Bray University of California, Berkeley Pacific Earthquake Engineering Research.

PERIOD-INDEPENDENT INTENSITY MEASURES

Peak Ground Acceleration PGAPeak 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

dt)t(axCAV

0

5

52

10

050.

.

dt)T,.(PSVSI

dt)t(ag

Ia 0

2

2

Page 14: NEEDS FOR PERFORMANCE-BASED GEOTECHNICAL EARTHQUAKE ENGINEERING Jonathan Bray University of California, Berkeley Pacific Earthquake Engineering Research.

PERIOD-DEPENDENT INTENSITY MEASURES

Spectral Accelerationat Fundamental Period

Spectral Combination (Cordova et al. 2000)

Spectral Vector (Conte, 2002)

Spectral Combination IM1I&2E

(Luco and Cornell, 2001)

0 *

hE

Y

*h

E

Y*h

EC

CF

Sa(T1)

Sa(T1)

)T(Sa)T(Sa

)T(SaSaC1

11

2

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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

Page 16: NEEDS FOR PERFORMANCE-BASED GEOTECHNICAL EARTHQUAKE ENGINEERING Jonathan Bray University of California, Berkeley Pacific Earthquake Engineering Research.

Source Characterization

• Source locations Segmentation m-A relations

• f(m) models

• Rate Large events (characteristic) Small events

Source: WGCEP, 1999

Page 17: NEEDS FOR PERFORMANCE-BASED GEOTECHNICAL EARTHQUAKE ENGINEERING Jonathan Bray University of California, Berkeley Pacific Earthquake Engineering Research.

SURFACE FAULT RUPTURE

Page 18: NEEDS FOR PERFORMANCE-BASED GEOTECHNICAL EARTHQUAKE ENGINEERING Jonathan Bray University of California, Berkeley Pacific Earthquake Engineering Research.

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

Page 19: NEEDS FOR PERFORMANCE-BASED GEOTECHNICAL EARTHQUAKE ENGINEERING Jonathan Bray University of California, Berkeley Pacific Earthquake Engineering Research.

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

Site Description Comments

A Hard Rock Strong, intact rock

B Rock Calif. rock; DW/S < 6 m

C Weathered/Soft Rock & Shallow Stiff Soil

6 m < DW/S < 60 m

D Deep Stiff Holocene Soil 60 m < DS

E Soft Clay 3 m < TC

F Potentially Liquefiable Sand Loose sat. sand

Page 20: NEEDS FOR PERFORMANCE-BASED GEOTECHNICAL EARTHQUAKE ENGINEERING Jonathan Bray University of California, Berkeley Pacific Earthquake Engineering Research.

  Northridge EQ Loma Prieta

  T = 0.3 s T = 1.0 s T = 0.3 s

Site SGS UBC SGS UBC SGS UBC

B .40(.08)

.46(.07)

.45(.11)

.52(.09)

.51(.10)

.52(.10)

C .54(.05)

.54(.06)

.60(.05)

.54(.06)

.38(.05)

.36(.05)

D .41(.04)

.42(.03)

.36(.03)

.41(.03)

.39(.07)

.39(.06)

Page 21: NEEDS FOR PERFORMANCE-BASED GEOTECHNICAL EARTHQUAKE ENGINEERING Jonathan Bray University of California, Berkeley Pacific Earthquake Engineering Research.

GROUND MOTION DATABASE

1208 records from 75 EarthquakesActive Plate MarginsMagnitudes 4.7 – 7.6Distances 0.1 – 250 km

Simplified Geotechnical SystemRodriguez-Marek et al. 2001

Fault Types

Rock

Soft Rock /Stiff

ShallowSoil

DeepStiff Soil

Normal

ReverseStrikeSlip

ReverseOblique

15%

27%58%

17

3117

10

0 . 1 1 1 0 1 0 0 1 0 0 0Distance (km)

4

5

6

7

8

Mag

nit

ud

e

Page 22: NEEDS FOR PERFORMANCE-BASED GEOTECHNICAL EARTHQUAKE ENGINEERING Jonathan Bray University of California, Berkeley Pacific Earthquake Engineering Research.

Near Fault Ground Motions

Northridge EQ:

Rinaldi Receiving Station Newhall - Pico Canyon