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Research Presentation at University of California-Berkeley
Department of Civil and Environmental Engineering, August 11th 2010
New Seismic Isolation Concepts for Improving the
Seismic Performance of Bridges
Ken Ogorzalek
Graduate Student
Stephen Mahin
Byron and Elvira Nishkian Professor of Structural Engineering
Director, Pacific Earthquake Engineering Research Center
Department of Civil & Environmental Engineering
University of California, Berkeley
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Outline
Introduction/Motivation
Segmental Disp. Control
Experimental Model
Ground Motions
Current Observations
Data Reduction/Analysis Earthquakeprotection.com
The Benicia-Martinez Bridge, San Francisco Bay Area
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Introduction
Seismic Performance Goals for a Sustainable and
Seismic Resilient Bridge?
Life Safety and Preventing Collapse
Post-Event Functionality
Infrastructures
Economics
Northridge
What is an Acceptable Condition 1989, Loma Prieta
for a Structure After an
Earthquake?
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Motivation
Understanding Behavior of Bridge
Response During Earthquakes
Displacements
Accelerations
Forces
Rotations
Bridge Isolation
Attenuated Forces/Accelerations
Non-Structural
Non-
Components
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Segmental Displacement Control
Isolated Bridge
UNRESTRAINED
Linear Isolation
Bearings
Triple Pendulum
U&&g
Isolation Bearings
PLAN VIEW
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Segmental Displacement Control
Isolated Bridge
UNRESTRAINED
U&&g
PLAN VIEW
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Segmental Displacement Control
Isolated Bridge
UNRESTRAINED
U&&g
Transverse Relative
Displacement
Control Displacements
PLAN VIEW
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Segmental Displacement Control
Isolated Bridge
RESTRAINED
U&&g
Lock-Up Guide
PLAN VIEW
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Segmental Displacement Control
Isolated Bridge
RESTRAINED
U&&g
PLAN VIEW
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Segmental Displacement Control
Isolated Bridge
RESTRAINED
U&&g
Transverse Relative
Displacement
PLAN VIEW
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Segmental Displacement Control
Lock-Up Guide
Longitudinal F-D
25
20
15
10
Longitudinal
Transverse 5
Force (kip)
Rotation 0
-8 -6 -4 -2 0 2 4 6 8
-5
-10
-15
-20
-25
Displacement (in)
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Guidelines for Experimental Model
Testbed Bridge Design for PEER Lifeline Project (Ketchum, et al. 2004)
120’ 150’ 150’ 150’ 120’
FULL
SCALE
BRIDGE
Smallest Column Cross
Section with Lowest
Reinforcement Ratio
AASHTO & SDC
Design
Considered the Simplest Superstructure Cross
Section and Short Column Bent
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Roadway Plate
Experimental Model
Bridge Deck
Lock--Up Guide
Lock
Triple Pendulum
Non-Compact
Non-
Isolator
Bridge Column
(Average Forces)
Linear Isolator
DECK 3
DECK 2
DECK 1
1/4 - 1/5 SCALE OF FULL BRIDGE
(By Weight/Length)
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Experimental Model
Isolation Performance for Different Level
Triple Friction Pendulum Bearing Excitations
Earthquake Protection Systems V
Disp (in.)
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Experimental Model
Linear Friction Pendulum Bearing
360˚
12˚
12˚
Earthquake Protection Systems
Disp (in.)
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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
Instrumentation
Wire Pots
Linear Pots
DCDTs
XYZ Accelerometers
5 Axis Load Cells
Strain Gauges
129 Total Channels
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Data Reduction/Analysis 37 - 111242 – Sine Y
Characterization Tests for Bridge Components 0.4
Y Normalized Force Displacement of TP Bearing - Center Deck West South
0.3
Triple Pendulum Bearing 0.2
0.1
V/W
V/W
-0.1
-0.2
-0.3
-0.4
-0.5
-0.6
-8 -6 -4 -2 0 2 4 6 8
Displacement (inches)
DISP (inches)
Friction Coefficients (Morgan 2007)
H1
µ1 = = 5%
2
µ 2 eff (L 1 + L 2 ) 2 µ 1 L1
µ2 = = 8%
L 2 L1
µ 3 eff (L2 + L3 ) µ 2 (L2 L1 ) 2 µ1 L1
µ3 = = 13 %
L3 L1
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Data Reduction/Analysis 37 - 111242 – Sine Y
Characterization Tests for Bridge Components
Y Force Displacement of Linear Bearing - North East
0.3
0.2
Linear Bearing 0.1
V/W
V/W
-0.1
-0.2
-0.3
-0.4
-6 -4 -2 0 2 4 6
Displacement (inches)
DISP (inches)
Friction Coefficients (Morgan 2007)
H1
µ1 = = 12 %
2
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Data Reduction/Analysis 37 - 111242 – Sine Y
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Data Reduction/Analysis
Ground Excitation Tests
Identification Similitude Requirements
1985 Chile, Llolleo XY
1995 Kobe, KJMA XYZ
1978 Iran, Tabas XYZ
1994 Northridge, Sylmar XYZ
2010 Chile XYZ
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Data Reduction/Analysis
1994 Sylmar, Northridge XYZ
DECK PLATE
(3) C-E
W-C
2.5” LOCK-UP GUIDE
(4)
TEST ID
164555: No Lock-Up Guide, No Plate
172926: 2.5” Lock-Up Guide, No Plate
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Data Reduction/Analysis
Lock--Up Guide View
Lock
164555 – Sylmar XYZ
NO Lock
Lock--Up Guide
172926 – Sylmar XYZ
Lock--Up Guide
Lock
164555: No Lock-Up Guide, No Plate 25
172926: 2.5” Lock-Up Guide, No Plate
Data Reduction/Analysis
Relative Transverse Displacement
Between Decks Transverse Relative Displacement of TP Bearings
1.5 W-C 164555
C-E 164555
W-C 172926
C-E 172926
1
0.5
Displacement (inches)
Disp (in)
0
-0.5
-1
-1.5
3 4 5 6 7 8 9 10 11
Time (sec)
Time (sec)
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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 Project Status
Non-Structural Components
Isolated Bridge Failure Mechanism
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Thank You!
