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

4. P E R
Framework for Performance-Based Engineering
{Loss analysis}{Damage analysis}{Dynamic analysis}{Hazard analysis}
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

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

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

7. EFFICIENCY
STIFF SLOPE

8. EFFICIENCY RESULTS
STIFF SLOPE DUCTILE SLOPE
Ts < 0.5 s
Ts > 0.5 s
Period Independent Arias Intensity Spectral 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)

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

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

13. 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

14. 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)

15. 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

16. Source Characterization
Source locations
Segmentation
m-A relations
f(m) models
Rate
Large events (characteristic)
Small events
WON’T SPEND A LOT OF TIME ON THIS B/C NOT MUCH PEER RESEARCH
Need to identify where sources are:
-easy for major strike slip faults such as those shown here
-more difficult for reverse slip faults (common in so. Cal), especially blind
thrusts
-must allow background seismicity for uknown faults
SEGMENTS: likely future earthquake sources along fault – e.g., we might think
SH is one likely source, NH is another, or both at once (assign weights to each
scenario) - relate fault size to magnitude using empircal relations (m-A scaling
relns)
F(m): we discuss in report several models (exponential, characteristic, maximum
magnitude), and what was recommended by a CDMG-USGS working group
for CA
RATE: need separate rate for large (characteristic) event on major sources, and
small eqks, which is assumed to follow G-R.
Source: WGCEP, 1999

17. SURFACE FAULT RUPTURE

18. Seismic Site Effects Local ground conditions Basin response
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

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

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

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

22. Near Fault Ground Motions
Near Fault Ground Motions Northridge EQ: Rinaldi Receiving Station Newhall - Pico Canyon