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New Seismic Isolation Concepts for Improving the New Seismic Isolation Concepts for Improving the Seismic Performance of BridgesSeismic Performance of Bridges

Research Presentation at University of California-BerkeleyDepartment of Civil and Environmental Engineering, August 11th 2010

Ken OgorzalekGraduate Student

Stephen MahinByron and Elvira Nishkian Professor of Structural EngineeringDirector, Pacific Earthquake Engineering Research Center

Department of Civil & Environmental EngineeringUniversity of California, Berkeley

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Outline

Introduction/Motivation

Segmental Disp. Control

Experimental Model

Ground Motions

Current Observations

Data Reduction/AnalysisThe Benicia-Martinez Bridge, San Francisco Bay Area

Earthquakeprotection.com

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Life Safety and Preventing Collapse

Post-Event Functionality Infrastructures Economics

Introduction

Seismic Performance Goals for a Sustainable and Seismic Resilient Bridge?

1989, Loma Prieta

Northridge

What is an Acceptable Condition What is an Acceptable Condition for a Structure After an for a Structure After an

Earthquake?Earthquake?

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Motivation

Understanding Behavior of Bridge Response During Earthquakes Displacements Accelerations Forces Rotations

Bridge Isolation Attenuated Forces/Accelerations

NonNon--Structural Structural ComponentsComponents

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Isolated Bridge

Segmental Displacement Control

UNRESTRAINED

PLAN VIEW

gU&&Triple Pendulum

Isolation Bearings

Linear Isolation Bearings

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Isolated Bridge

Segmental Displacement Control

UNRESTRAINED

PLAN VIEW

gU&&

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Isolated Bridge

Segmental Displacement Control

UNRESTRAINED

PLAN VIEW

gU&&Transverse Relative

Displacement

Control Displacements

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Isolated Bridge

Segmental Displacement Control

RESTRAINED

PLAN VIEW

gU&&Lock-Up Guide

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Isolated Bridge

Segmental Displacement Control

PLAN VIEW

gU&&

RESTRAINED

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Isolated Bridge

Segmental Displacement Control

PLAN VIEW

gU&&Transverse Relative

Displacement

RESTRAINED

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Lock-Up Guide

Segmental Displacement Control

-25

-20

-15

-10

-5

0

5

10

15

20

25

-8 -6 -4 -2 0 2 4 6 8

Forc

e (k

ip)

Displacement (in)

LongitudinalTransverseRotation

Longitudinal F-D

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Testbed Bridge Design for PEER Lifeline Project (Ketchum, et al. 2004)

FULL SCALE

BRIDGE

Considered the Simplest Superstructure Cross Considered the Simplest Superstructure Cross Section and Short Column BentSection and Short Column Bent

Smallest Column Cross Smallest Column Cross Section with Lowest Section with Lowest Reinforcement RatioReinforcement Ratio

120’ 150’ 150’ 150’ 120’

AASHTO & SDC Design

Guidelines for Experimental Model

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Bridge DeckBridge Deck

NonNon--Compact Compact Bridge ColumnBridge Column

Triple Pendulum Triple Pendulum IsolatorIsolator

(Average Forces)(Average Forces)

Linear IsolatorLinear Isolator

LockLock--Up GuideUp Guide

Experimental Model Roadway PlateRoadway Plate

1/4 - 1/5 SCALE OF FULL BRIDGE (By Weight/Length)

DECK 1DECK 2

DECK 3

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Experimental ModelIsolation Performance for Different Level

ExcitationsTriple Friction Pendulum Bearing

Earthquake Protection Systems V

Disp (in.)

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Experimental Model

Linear Friction Pendulum Bearing

Earthquake Protection Systems

V

Disp (in.)

12˚12˚

360˚

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Experimental Model

Longitudinal Elevation View

306 in / 25.5 ft / 7.8 m

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Experimental Model

Transverse Elevation View

75 in / 6.25 ft / 1.9 m

85 in / 7.1 ft / 2.2 m

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Experimental Model

InstrumentationInstrumentation Wire Pots Linear Pots DCDTs XYZ Accelerometers 5 Axis Load Cells Strain Gauges

129 Total Channels

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Data Reduction/Analysis 37 37 -- 111242 111242 –– Sine YSine Y

-8 -6 -4 -2 0 2 4 6 8-0.6

-0.5

-0.4

-0.3

-0.2

-0.1

0

0.1

0.2

0.3

0.4Y Normalized Force Displacement of TP Bearing - Center Deck West South

V/W

Displacement (inches)

V/W

Triple Pendulum Bearing

%52

11 ==

Hµ

( )%8

2

12

112122 =

+

=LL

LLLeff µµµ

( ) ( )%13

2

13

111223233 =

+

=LL

LLLLLeff µµµµ

Friction Coefficients (Morgan 2007)

DISP (inches)

Characterization Tests for Bridge ComponentsCharacterization Tests for Bridge Components

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-6 -4 -2 0 2 4 6-0.4

-0.3

-0.2

-0.1

0

0.1

0.2

0.3Y Force Displacement of Linear Bearing - North East

V/W

Displacement (inches)

Data Reduction/Analysis 37 37 -- 111242 111242 –– Sine YSine Y

DISP (inches)

V/W

Linear Bearing

%122

11 ==

Hµ

Friction Coefficients (Morgan 2007)

Characterization Tests for Bridge ComponentsCharacterization Tests for Bridge Components

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Data Reduction/Analysis 37 37 -- 111242 111242 –– Sine YSine Y

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Data Reduction/Analysis

Ground Excitation TestsGround Excitation Tests

Identification

1985 Chile, Llolleo XY

1995 Kobe, KJMA XYZ

1978 Iran, Tabas XYZ

1994 Northridge, Sylmar XYZ

2010 Chile XYZ

Similitude RequirementsSimilitude Requirements

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Data Reduction/Analysis

TEST ID164555: No Lock-Up Guide, No Plate

172926: 2.5” Lock-Up Guide, No Plate

DECK PLATE(3)

2.5” LOCK-UP GUIDE(4)

W-C

1994 Sylmar, Northridge XYZ1994 Sylmar, Northridge XYZ

C-E

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Data Reduction/Analysis LockLock--Up Guide ViewUp Guide View164555 164555 –– Sylmar XYZSylmar XYZ

NO NO LockLock--Up GuideUp Guide

172926 172926 –– Sylmar XYZSylmar XYZLockLock--Up GuideUp Guide

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3 4 5 6 7 8 9 10 11

-1.5

-1

-0.5

0

0.5

1

1.5

Time (sec)

Dis

plac

emen

t (in

ches

)

Transverse Relative Displacement of TP Bearings

W-C 164555C-E 164555W-C 172926C-E 172926

Data Reduction/Analysis

Time (sec)

Dis

p (in

)

164555: No Lock-Up Guide, No Plate172926: 2.5” Lock-Up Guide, No Plate

Relative Transverse Displacement Relative Transverse Displacement Between DecksBetween Decks

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Future Considerations

Complete Data Reduction and Analysis of Experimental Tests OpenSees 3D Analytical Model

Validate Experimental Test Apply to Full-Scale Bridge

Performance Based Design Criteria Design Guidelines for Segmental Displacement Control

Design of Lock-Up Guide Non-Structural Components

Isolated Bridge Failure Mechanism

Project StatusProject Status

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Thank You!