modelinggp of seismic response of thick soil sites and depth … response/hashash-mid... · 2020....

1

Modeling of Seismic Response of thick soil sitesg pand Depth dependent site coefficients

TRB COMMITTEE AFF50 - SEISMIC DESIGN OF BRIDGESGeo Seismic Concerns Subcommittee Meeting

23 January 2007 10:15 am – 12:00 pm, Marriott Hotel, Balcony Room D

Youssef Hashash ([email protected])In collaboration with Graduate Research Assistants:In collaboration with Graduate Research Assistants:

Chi-Chin Tsai, Camilo Phillips, Duhee Park (now @ Hanyang University)

University of Illinois at Urbana-Champaign

Mid-America Earthquake Center

University of Illinois at Urbana Champaign

2

Outline

• Backgroundg• Site response analysis of deep soil deposits• PSHA-NL: Integrated probabilistic seismic• PSHA-NL: Integrated probabilistic seismic

hazard analysis with non-linear site effectsNEHRP t l d th d d t it ffi i t• NEHRP style depth dependent site coefficients

• Conclusions


3

Background: Mid-America Regional Issues

St.LouisMissouriMi i i i

E-W Section through Memphis

Cairo

Illinois

Sea level200 mMemphis

MississippiFlood Plain

New Madrid

Kentucky

Paleocene

1000 m

Recent and Plio-pleistocene

50 km0

Memphis

Tennessee

Mi i i

PaleoceneCretaceousPaleozoic RockLower Eocene

p

Middle and upper Eocene

MississippiArkansas Note vertical

scale exaggeration


4

Modeling of site response of thick soil deposit- DEEPSOIL

-Nonlinear analysis (time domain): >Pressure dependent soil model>New Viscous Damping formulationNew Viscous Damping formulation

-Equivalent linear (Frequency domain):> Three types of complex shear modulus

-Graphical User Interface, User Base ~ 400 users


http://www.uiuc.edu/~DEEPSOIL

5

Mississippi Embayment properties

• Dynamic properties from laboratory tests

– Laird and Stokoe (1993) & Chang 0.6

0.8

1

Gm

ax

(a)

23

456

7

7

( ) get al. (1992)

0 2 0 0 4 0 0 6 0 0 8 0 0 1 0 0 0

Vs

( m / s e c )

0

0.2

0.4G/G 65432

1

12 7

0

1 0 0

2 0 0

3 0 0

( a )00.0001 0.001 0.01 0.1 1

1: Proposed 3m2: Proposed 10.5m3: Proposed 26m4: Proposed 56.5m5: Proposed 114m

1: EPRI 3m2: EPRI 10.5m3: EPRI 26m4: EPRI 56.5m5: EPRI 114m

Shear strain, γ (%)

3 0 0

4 0 0

5 0 0

6 0 0

Dep

th (m

)

12

15

%) 1

(b) 12 3 4 5

6

5: Proposed 114m6: Proposed 228.5m7: Proposed 1000m

5: EPRI 114m6: EPRI 228.5m7: EPRI 1000m

7 0 0

8 0 0

9 0 0L o w l a n d s P r o f i l eU p l a n d s P r o f i l e

3

6

9

Dam

ping

ratio

(%

65

43

26

7

7


1 0 0 0 Hardrock Vs=3000 m/sec 00.0001 0.001 0.01 0.1 1

Shear strain, γ (%)

6

Significance of overburden pressure dependency

1000 m Soil Column 100 m Soil Column

0.05

0.1

n(g

) Soil Column: 1000 m0.05

0.1

n (g

) Soil Column: 100 m

Amplificationof

Long Period -0.05

0

Acc

eler

atio

n

-0.05

0

Acc

eler

atio

n

Input Motion (after deconvolution):Yerba Buena

1000 m ColumnSi P i d 5 0

Waves-0.1

0 10 20 30 40Time (sec)

-0.10 10 20 30 40

Time (sec)

Loma Prieta Earthquake

0.1

Acc

eler

atio

n (g

) Site Period: 5.0 sec

Propagation of

High Frequency

0.1

Acc

eler

atio

n (g

)0.01 Input Motion (after deconvolution)

Pressure Dependent Model

Pressure Independent Model

Spec

tral A

Frequency Waves

0.01Sp

ectra

l A100 m ColumnSite Period: 0.9 sec


0.01 0.1 1 10Period (sec) 0.01 0.1 1 10Period (sec)

7Integrated Probabilistic Seismic Hazard Analysis with Non-linear Site Effects (PSHA-NL)

Site

1D Nonlinear sitePath

Fault Surficial layers

1D Nonlinear site response analysis using DEEPSOIL

Source

Probabilistic seismic hazard analysis with ground motion generation Park & Hashash (2003)

Develop an integrated PSHA-NL tool that combines source/path effects + site effects: applied to Mid-America

Output1. A computational framework that can define Seismic Hazard / Representative ground motions

at any location in Upper Mississippi Embayment


at any location in Upper Mississippi Embayment.2. Develop NEHRP style site coefficients

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PSHA w/ Nonlinear Site Effects: PSHA-NL

Step 1 Select Site coordinates, site profiles, and dynamic properties.

Step 2 Perform PSHA at hard rockStep 2 Perform PSHA at hard rock.Choose number of simulations (N)

Output: a) Suite of hard rock motions, b) UHRS Point Source model & finite fault model

Step 3Propagate the hard rock motions

through B/C BoundaryOutput: UHRS

Step 4Propagate the hard rock motions through

site profiles using DEPPSOIL

Is UHRS close to USGS B/C hazard maps?No

Output: a) suite of site specific motions

Yes

hazard maps? Output: a) suite of site specific motions, b) UHRS

S 5


Step 5Develop depth dependent site coefficients

9

PSHA-NL: I-Site selection

Site No

Ss (g) Sl (g) PGA(g)

Fa Fv

1 0.656 0.20 0.307 1.28 2

37

Carbondale

62 0.75 0.22 0.34 1.2 1.96

3 1.00 0.30 0.568 1.1 1.8

4 1.25 0.34 0.66 1.0 1.72

36

23

45 7

85 1.50 0.40 0.796 1.0 1.6

6 1.84 0.50 1.01 1.0 1.5

35Memphis

1

23

34

1


-93 -92 -91 -90 -89 -8834

10PSHA-NL: III-PSHA ground motion generation Comparison of Uniform Hazard Response Spectra with USGS (B/C boundary)

Number of motions generated 9,000 – 10,000

Site 1 (2% 50 years exceedence UHRS)

0.6

0.7

0.8

0.9FINSIM w/o capSMSIM with cap2002map


1

1.2

1.4

FINSIM w/o capSMSIM with cap2002map


1 5

2

2.5FINSIM w/o capSMSIM w/o capSMSIM with cap2002map

0

0.1

0.2

0.3

0.4

0.5

0 01 0 1 1 10

Sa(

g)

0

0.2

0.4

0.6

0.8

0.01 0.1 1 10

Sa(

g)

0

0.5

1

1.5

0.01 0.1 1 10

Sa(

g)

0.01 0.1 1 10Period(sec)


0 70.80.9

1FINSIM w/o capSMSIM with cap2002map

0.01 0.1 1 10Period(sec)


1.4

1.6

1.8

FINSIM w/o capSMSIM with cap

Period(sec)


2 5

3

3.5FINSIM w/o capSMSIM w/o capSMSIM with cap

00.10.20.30.40.50.60.7

Sa(

g)

2002map

0

0.2

0.4

0.6

0.8

1

1.2

Sa(

g)

2002map

0

0.5

1

1.5

2

2.5

Sa(

g)

SMSIM with cap2002map


00.01 0.1 1 10

Period(sec)

00.01 0.1 1 10

Period(sec)

00.01 0.1 1 10

Period(sec)

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PSHA-NL: IV-Site effects & response

• 9000 generated rock motions are propagated through randomized soil profiles

0 200 400 600 800 1000 1200

0

Vs (m/s)

(b)

– 30 profiles

Shear Wave Velocity Dynamic Soil Properties Weight 200

Profiles (No. of Simulation)

ME properties 0.75w (22) Uplands 400

(m)

EPRI properties 0.25w (8)

ME properties 0.75w (22) Lowlands

EPRI ti 0 25 (8)

600

Dep

th

EPRI properties 0.25w (8) 800

UplandsMean - 1standard deviationMean + 1standard deviationRandomized profile


1000

Randomized profile

0 200 400 600 800 1000 1200

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PSHA-NL: IV-Site effects & response -Depth dependent UHRS

2Site D (NEHRP)

30

2 30 m100 m200 m300 m

1.5

30 m

100 m200 m

300 m

500 m1.5

300 m500 m1000 m30m Amp100m Amp200m Amp300m Amp500 m Amp1000m Amp

1

PSA

(g)

1000 m

1

PS

A (g

)

1000m AmpNEHRP Site D

0.50.5

00.01 0.1 1 10

Period (sec)

00.01 0.1 1 10

Period (sec)


Period (sec)

Site 6Period (sec)

13PSHA-NL: V-Simplified NEHRP style depth dependent Site Factors

Uplands Profile

0.7 0.8 0.9 1 1.1 1.2 1.3 1.4

0

Fa

1 1.5 2 2.5 3 3.5Fv

200

400

h (m

)

600

Dep

th

Ss=1.0gSs=0.75g

Ss>=1.25gS

l=0.4g

Sl=0.3g

S >=0 5g

800 PSHA-NL (PS)

PSHA-NL (FF)

NEHRP

Sl>=0.5g


1000

NEHRP

14Incorporate updated Hazard maps with depth dependent site factors:2% in 50 year hazard map of PGA in ME

37

Carbondale

37

Carbondale(a) USGS B/C boundary (b) With NEHRP Class Site D

35

36

Memphis35

36

Memphis

Unit: g

1.4

1.6

CarbondaleCarbondale

-93 -92 -91 -90 -89 -8834

-93 -92 -91 -90 -89 -8834

(d) PSHA NL(FF) using 0 6

0.8

1

1.2

atitu

de

36

37

36

37(d) PSHA-NL(FF) using spectrum ratio

(c) PSHA-NL(FF) using proposed site coefficients

0

0.2

0.4

0.6

La

Memphis3535

Memphis


-93 -92 -91 -90 -89 -8834

-93 -92 -91 -90 -89 -8834

Longitude

15Incorporate updated Hazard maps with depth dependent site factors:2% in 50 year hazard map of 0.2 Sec SA in ME

37

Carbondale

37


35

36

Memphis35

36

Memphis

Unit: g

3.2

3.6

-93 -92 -91 -90 -89 -8834

CarbondaleCarbondale-93 -92 -91 -90 -89 -88

34

1.6

2

2.4

2.8

Latit

ude

36

37

36

37

Ca bo da e(d) PSHA-NL(FF) using spectrum ratio

(c) PSHA-NL(FF) using proposed site coefficient

0

0.4

0.8

1.2

Memphis3535

Memphis

Mid-America Earthquake Center-93 -92 -91 -90 -89 -88

34-93 -92 -91 -90 -89 -88

34

Longitude

16Incorporate updated Hazard maps with depth dependent site factors:2% in 50 year hazard map of 1.0 sec SA in ME

37

Carbondale

37


35

36

Memphis 35

36

Memphis

Uint: g

2 1

2.4

2.7

-93 -92 -91 -90 -89 -8834

CarbondaleCarbondale

-93 -92 -91 -90 -89 -8834

(d) PSHA NL(FF) using(c) PSHA NL(FF) using 0 9

1.2

1.5

1.8

2.1

atitu

de

36

37

36

37(d) PSHA-NL(FF) using spectrum ratio

(c) PSHA-NL(FF) using proposed site coefficient

0

0.3

0.6

0.9La

Memphis3535

Memphis


-93 -92 -91 -90 -89 -8834

-93 -92 -91 -90 -89 -8834

Longitude

17

Conclusions

• NEHRP site factors do not account for effect of d d itdeep deposits.

• A possible remedy is the inclusion of depth dependent site factors.

• For important bridges/structures site specific p g panalyses are needed

• DEEPSOILDEEPSOIL …..


modelinggp of seismic response of thick soil sites and depth … response/hashash-mid... · 2020....

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