hybrid sliding-rocking post-tensioned segmental bridges in seismic ...

HYBRID SLIDING-ROCKING
POST-TENSIONED SEGMENTAL
BRIDGES IN SEISMIC REGIONS
Petros Sideris, Ph.D.
Department of Civil, Structural, and Environmental Engineering
University at Buffalo, The State University of New York
September 17, 2012
Major Funding Agency:
RESEARCH GROUP
• Petros Sideris
Post-doctoral Research Fellow and Adjunct Lecturer,
Dept. of CSEE at UB
• Amjad J. Aref
Professor, Dept of CSEE at UB
• Andre Filiatrault
Professor, Dept of CSEE at UB
This presentation is based on:
Sideris, P. (2012). "Seismic Analysis and Design of Precast Concrete
Segmental Bridges." Ph.D. Dissertation, State University of New York at
Buffalo, Buffalo, NY, U.S.A.
P. Sideris,
Sept. 17, 2012
OVERVIEW
INTRODUCTION
DEVELOPMENT OF HSR SEGMENTAL MEMBERS
EXPERIMENTAL VALIDATION OF HSR BRIDGES:
• Seismic Testing
• Quasi-Static Testing
NUMERICAL MODELING:
• ABAQUS & SAP2000 Modeling
COMPONENT TESTING:
• Response of Strand-Anchor Systems
• Frictional Properties of HSR Joints
CONCLUSIONS
ACKNOWLEDGEMENTS
P. Sideris,
Sept. 17, 2012
INTRODUCTION
Problem Statement:
• Thousands of bridges in the US classified as
“structurally deficient or functionally obsolete”
Many located in moderate/high seismicity areas
Need for immediate replacement/retrofit
• Accelerated Bridge Construction (ABC) Techniques:
Minimal operation disruption
Minor environmental consequences
Limited socio-economical impact
• Precast Concrete Segmental Bridges:
Definition:
• Members composed of segments post-tensioned together with
steel tendon
Construction Process:
• Segments constructed in precast plant Transported to site
System assembly (Joint preparation & tendon grouting)
P. Sideris,
Sept. 17, 2012
INTRODUCTION
Problem Statement:
• Precast Concrete Segmental Bridges:
(Otay River Bridge, 2007)
(Otay River Bridge, 2007)
(C&D Canal
Bridge, 1995)
INTRODUCTION
Precast Concrete Segmental Bridges:
• Advantages:
Higher construction quality (precast plants)
Erection rapidity
• Concerns – Technical Challenges:
Seismic performance is largely unknown (Joint response under
earthquake loading)
q g)
Research Objectives:
• Extension of ABC in high seismicity regions
Hybrid Sliding-Rocking (HSR) Post-tensioned
Segmental Members HSR Bridges
• System Development: Mitigation of seismic loading with
low damage
• Seismic performance evaluation
• Numerical modeling techniques
P. Sideris,
Sept. 17, 2012
P. Sideris,
Sept. 17, 2012
1

INTRODUCTION
OVERVIEW
DEVELOPMENT OF HSR SEGMENTAL MEMBERS
EXPERIMENTAL VALIDATION OF HSR BRIDGES:
• Seismic Testing
• Quasi-Static Testing
NUMERICAL MODELING:
• ABAQUS & SAP2000 Modeling
COMPONENT TESTING:
• Frictional Properties of HSR Joints
• Response of Strand-Anchor Systems
CONCLUSIONS & ORIGINAL CONTRIBUTIONS
ACKNOWLEDGEMENTS
P. Sideris,
Sept. 17, 2012
HSR SEGMENTAL MEMBERS
Fundamental Concepts:
• Hybrid Sliding-Rocking
(HSR) Joints:
Joint Sliding
Joint Rocking
• Internal Unbonded Posttensioning
of Linear or
Nonlinear Geometry:
Linear Geometry Straight
tendons, parallel to member axis
Nonlinear Paths Curved tendons
Benchmark System
P 1
P 2
Tendon
HSR
Joint
Duct
Duct adaptor
Rigid connection
P. Sideris,
Sept. 17, 2012
HSR SEGMENTAL MEMBERS
Response of Benchmark Configuration:
• Slip-dominant Joints:
Sliding until capacity is reached
• Resistance by tendon bearing forces (dowel effect) and friction
• Re-centering only by tendon bearing forces (dowel effect)
• Sliding amplitude controlled by diameter of duct adaptor
• Variation of PT bearing forces controlled by height of duct
adaptor
Tendon restoring force
(Dowel effect)
Rocking, after
Tendon
sliding capacity
Top
Segment Duct
is reached
HSR SEGMENTAL MEMBERS
Response of Benchmark Configuration:
• Slip-dominant Joints:
Mechanics of Joint Sliding:
• Constant PT force and Axial Compression
• Rotations are restrained
• Lateral cyclic loading is applied
Bottom
Segment
Duct
adaptor
P. Sideris,
Sept. 17, 2012
P. Sideris,
Sept. 17, 2012
HSR SEGMENTAL MEMBERS
Response of Benchmark Configuration:
• Slip-dominant Joints:
Mechanics of Joint Sliding:
HSR SEGMENTAL MEMBERS
Response of Benchmark Configuration:
• Slip-dominant Joints:
Mechanics of Joint Sliding:
Tendon Bearing Forces
Joint Lateral Reaction
Friction + PT
Bearing Forces
Friction
Stiffening at
Unloading Branches
Ultimate Sliding
Joint Sliding
Locking Forces
Force (kips)
50
0
-50
Effect of Duct Diameter
d =0.9
d
d d
=0.75
-0.5 0 0.5
Sliding (in)
Force (kips)
50
0
-50
Effect of Duct Adaptor Height
h da
=1.5
h da
=0.75
-0.5 0 0.5
Sliding (in)
P. Sideris,
Sept. 17, 2012
P. Sideris,
Sept. 17, 2012
2

'
'
c
cm
'
cc cc
HSR SEGMENTAL MEMBERS
Response of Benchmark Configuration:
• Rocking-dominant Joints:
Pure rocking response
• Resistance and re-centering by PT tendon axial forces
• Duct adaptors are not required
HSR SEGMENTAL MEMBERS
Response of Benchmark Configuration:
• Rocking-dominant Joints:
Mechanics of Joint Rocking :
M
Concrete
Proportionality Limit
Confined Concrete
Ultimate Strain
M
Concrete
Proportionality Limit
Confined Concrete
Ultimate Strain
Unconfined Concrete
Ultimate Strength
a f
Top
Segment
Bottom
Segment
Tendon
Duct
Duct
adaptor
Unconfined Concrete
Ultimate Strength
Decompression
Stress:
0.5 f c
M
N
'
0.5 f c
c
Decompression
y
x
M
ϕ
c
0.003
0.85 f c
c
β 1 c
Cover neglected
c
c
β cc c
ϕ
Strain:
c
N
c
Explain
P. Sideris,
Sept. 17, 2012
P. Sideris,
Sept. 17, 2012
HSR SEGMENTAL MEMBERS
Response of Benchmark Configuration:
• Effects of PT Geometry:
Linear PT Geometry:
Higher restoring forces at
larger sliding amplitudes
Nonlinear PT Geometry:
Higher restoring forces even
at smaller sliding amplitudes
Thus, PT geometry affects
the joint mode to be exhibited
Tendon
bearing
forces
P. Sideris,
Sept. 17, 2012
HSR SEGMENTAL MEMBERS
Seismic Performance of HSR Joints
• General (both joint modes):
Control seismic forces by modifying joint stiffness and
strength
• Slide Mode:
High energy dissipation with low damage (Friction)
Moderate self-centering
• Depends on PT system, duct adaptors and frictional properties
at joint interface
• Rocking Mode:
Low energy dissipation (Concrete crushing or PT yielding)
High self-centering
• Excellent at lower deformations, but reduces as damage
progresses
P. Sideris,
Sept. 17, 2012
HSR SEGMENTAL MEMBERS
HSR Members Types
• HSR-SD members:
Slip-dominant joints and Linear PT geometry
Intended for substructures
• HSR-RD members:
Rocking-dominant Joints and Nonlinear PT Geometry
Intended for superstructures
HSR SEGMENTAL MEMBERS
Seismic Performance of HSR Members
• As dictated by the dominant joint response mode
• Also:
HSR-SD members:
• Need for external energy dissipation is alleviated
HSR-SD SD and HSR-RD RD members:
• Control of higher modes (Different mode shapes
activate different joints or response modes)
P. Sideris,
Sept. 17, 2012
P. Sideris,
Sept. 17, 2012
3

C.M.
INTRODUCTION
OVERVIEW
DEVELOPMENT OF HSR SEGMENTAL MEMBERS
EXPERIMENTAL VALIDATION OF HSR BRIDGES:
• Seismic Testing
• Quasi-Static Testing
NUMERICAL MODELING:
• ABAQUS & SAP2000 Modeling
COMPONENT TESTING:
• Response of Strand-Anchor Systems
• Frictional Properties of HSR Joints
CONCLUSIONS & ORIGINAL CONTRIBUTIONS
ACKNOWLEDGEMENTS
P. Sideris,
Sept. 17, 2012
SEISMIC TESTING
Prototype System (Megally et al., 2002):
• Superstructure:
Five-span single-cell box girder bridge
Each span post-tensioned with harped shaped tendons
• Substructure:
Reinforced Concrete – 30 ft highh
(Megally et et all, all, 2002) 2002)
30’
P. Sideris,
Sept. 17, 2012
SEISMIC TESTING
Test Specimen:
• Single-span single-cell bridge - Both of its supports
overhanging at equal lengths (25% of span)
• Large-scale model (S L =2.39):
Superstructure:
• HSR-RD RD member
• 8 segments and 12 internal unbonded PT tendons
Substructure:
• Two single-column HSR-SD piers
• 5 segments and 8 internal unbonded PT tendons per pier
• Cap beam at top end and Foundation block at bottom end
• All components used the same post-tensioning system
SEISMIC TESTING
Test Specimen:
2'-4 3/8"
2'-0" 7" 1'-3 1/2"
2'-0"
2'-0"
2'-0"
2'-0"
2'-5"
1'-3 7/8"
11'-0 3/8"
3"
1'-6"
8 1/2"
Top anchorage of PT system
Lateral
2'-10 7/8"
Restrainer
Cap beam
Duct t& Duct
Adaptor
Duct not used during
shake table testing
Pier Segment
Foundation Block
Bottom anchorage
of PT system
5"
2'-1"
2 1/2"
10" 10"
2'-1"
2 1/2"
P. Sideris,
Sept. 17, 2012
9'-0"
P. Sideris,
Sept. 17, 2012
SEISMIC TESTING
Test Specimen:
SEISMIC TESTING
Test Specimen:
5'-9 3/4" 8'-4 1/2" 8'-4 1/2" 8'-4 1/2"
5'-9 3/4" 8'-4 1/2"
8'-4 1/2" 8'-4 1/2"
1'-2 7/8"
9"
9"
9"
9"
1'-2 7/8"
Straight Tendons
–Top Flange
Spare Straight Ducts – Top
Flange (not used during testing)
1'-10 1/2"
2'-0"
2'-0"
2'-0"
2'-0"
2'-0"
2'-5"
2'-4"
Cap Beam
Pier Segment
Foundation Block
Tendons
Deck
Segment
P. Sideris,
Sept. 17, 2012
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Sept. 17, 2012
4

SEISMIC TESTING
Test Specimen:
Sand Bag
Lateral
Restrainer
Suspension
Safety System
Cap Beam
Pier
Foundation
Block
(SEESL at UB, May 2010)
SEISMIC TESTING
Test Specimen:
• Superstructure-to-substructure connection:
Non-integral Superstruct. simply supported on cap beams
• Dimensions:
61.9 ft long (pier-to-pier distance: 41.9 ft)
14.2 ft high h including cap beam and foundation block (16.5
ft including superstructure as well)
• Design:
AASHTO LRFD Bridge Design Specifications (2007)
PCI Bridge Design Manual (2003)
R sup =2.5 and R sub =3.75 (=1.5×2.5)
Implementation of HSR concepts
Parts of design validated through FE analysis
P. Sideris,
Sept. 17, 2012
P. Sideris,
Sept. 17, 2012
SEISMIC TESTING
Test Specimen:
• HSR Joint Design:
Superstructure:
• Match-cast joints
• No duct adaptors
• Nominal sliding capacity: ± 0.4”
Substructure:
• Silicone material at all joints:
• Target friction in range of 0.08 – 0.10
• Uniform frictional properties over the interface
• Stability during erection
• Duct adaptors of I.D. of 1.375” and length of 1.5” at segments
• No duct adaptors at cap beams and foundation blocks
• Nominal sliding capacity: ± 0.775” (or ± 0.5375” at ends)
SEISMIC TESTING
Specimen Configurations:
• Superstructure-to-cap beam connectivity:
Free sliding
Fully restrained lateral sliding (lateral restrainers in contact)
Limited lateral sliding (lateral restrainers at distance of 4”)
• Loading conditions:
Fully unloaded specimen
Fully loaded specimen
Partially loaded specimen
P. Sideris,
Sept. 17, 2012
P. Sideris,
Sept. 17, 2012
SEISMIC TESTING
Specimen Configurations:
(SEESL at UB, May 2010)
(SEESL at UB, May 2010)
(SEESL at UB, May 2010)
P. Sideris,
Sept. 17, 2012
SEISMIC TESTING
Ground Motion Input:
• Ground Motion (GM) Ensembles:
Subset of FEMA P695 Far-field GM set (5 out of 22 motions)
Subset of FEMA P695 Near-field GM set (6 out of 28 motions
– 3 with and 3 without pulses)
• Seismic Hazard:
Modification of AASHTO (2007) Design Spectrum following
the process of FEMA 356
Hazard Levels:
• Low DE (25% in 50 yrs – DE/1.5)
• DE (10% in 50 yrs)
• MCE (2% in 50 yrs – 1.5×DE)
• Amplified DE-1 (2.4×DE)
• Amplified DE-2 (3.6×DE)
P. Sideris,
Sept. 17, 2012
5

SEISMIC TESTING
Ground Motion Input:
SA (g)
• Spatial Variability (Asynchronous Base Excitation)
Time delay between the time instants that the seismic wave
reaches each piers
• ∆t 1 =0.05 sec (based on soil profile at the site)
• ∆t 2 =0.5 sec (amplified)
1.8
1.5
1.2
0.9
0.6
0.3
0.0
Horizontal Motions – Model Domain
Range of
interest
DE
F-F GM Set
N-F GM Set
0 0.4 0.8 1.2
T (sec)
SA (g)
2.4
2.0
1.6
1.2
0.8
0.4
0.0
Vertical Motions – Model Domain
DE
F-F GM Set
N-F GM Set
0 0.4 0.8 1.2
T (sec)
P. Sideris,
Sept. 17, 2012
SEISMIC TESTING
Testing Program:
• System Identification Tests
Objective: Monitor state of damage
~ 175 White noise tests
• Shake Table Testing
13 Phases – 15 Days – ~145 testst
Combining:
• Loading conditions
• Ground motion types
• Seismic hazard levels
P. Sideris,
Sept. 17, 2012
SEISMIC TESTING
System Identification:
• White Noise Tests:
Frequency and damping ratio
SEISMIC TESTING
System Identification:
• White Noise Tests:
Frequency and damping ratio
X Direction
Y Direction
Z Direction
Unloaded Specimen
(before testing)
Fully Loaded Specimen
(after some testing)
Partially Loaded Specimen
(before end of testing)
f (Hz) ξ f (Hz) ξ f (Hz) ξ
Mode 1 0.27 6.2% 0.34 7.2% 0.35 7.2%
Mode 2 0.028 5.9% 0.030 11.5% 0.029 10.1%
Mode 1 0.35 6.4% 0.56 4.0% 0.55 6.1%
Mode 2 0.20 11.2% 0.31 9.1% 0.33 12.4%
Mode 3 0.065 5.2% 0.073 4.3% 0.071 3.8%
Mode 4 0.039 0.7% 0.039 2.7% 0.047 1.8%
Mode 1 0.14 1.3% 0.17 2.1% 0.16 1.8%
Mode 2 0.045 5.6% 0.060 2.8% 0.062 3.6%
Mode 3 0.022 1.5% 0.029 5.0% ‐‐‐ ‐‐‐
ude
Transfer Function Amplit
15
10
5
Transfer Functions - Window Length=6000
1 st Mode
Transfer Function Amplitude – Transverse Direction
2 nd Mode 3 rd Mode
4 th Mode
0
0 10 20 30 40 50
Frequency (Hz)
as1y/afe1y a
as2y/afe2y
a
as3y/afe3y a
as4ney/afe3y a
as4nwy/afe3y a
as5ney/afw3y a
as5nwy/afw3y
a
as6y/afw3y a
as7y/afw2y a
as8y/afw1y a
50
P. Sideris,
Sept. 17, 2012
P. Sideris,
Sept. 17, 2012
SEISMIC TESTING
System Identification:
• White Noise Tests:
Mode Shapes:
SEISMIC TESTING
System Identification:
• White Noise Tests:
Mode Shapes:
Y-Direction: 1 st Mode Shape
200
X-Direction: 1 st Mode Shape
200
X-Direction: p 2 nd Mode Shape
300
Plan View
3-D View
Z (in)
150
100
50
Z (in)
150
100
50
Y (in)
200
100
Z (in)
200
100
0
0
0
0 100 200 300 400 500 600 700
X (in)
0
0 100 200 300 400 500 600 700
X (in)
0
0 100 200 300 400 500 600 700
X (in)
200
400
600
X (in)
0
300
200
100
Y (in)
P. Sideris,
Sept. 17, 2012
P. Sideris,
Sept. 17, 2012
6

SEISMIC TESTING
System Identification:
• White Noise Tests:
Mode Shapes:
Y-Direction: 2 nd Mode Shape
SEISMIC TESTING
System Identification:
• White Noise Tests:
Mode Shapes:
Y-Direction: 3 rd Mode Shape
300
Plan View
3-D View
200
Side Elevation
3-D View
Y (in)
200
100
0
-100
0 100 200 300 400 500 600 700
X (in)
Z (in)
200
100
0
0
200
400
X (in)
600
0
-100
100
Y (in)
200
300
Z (in)
150
100
50
0
-100 -50 0 50 100 150 200 250 300
Y (in)
Z (in)
200
100
0
0
200
400
600
X (in)
-100 0 100
Y (in)
200
300
P. Sideris,
Sept. 17, 2012
P. Sideris,
Sept. 17, 2012
SEISMIC TESTING
System Identification:
• White Noise Tests:
Mode Shapes:
300
200
100
Plan View
Y-Direction: 4 th Mode Shape
Z (in)
200
100
3-D View
Z (in)
System Identification:
• White Noise Tests:
Mode Shapes:
150
100
Z-Direction: 1 st Mode Shape
SEISMIC TESTING
Z (in)
150
100
50
Z-Direction: 2 nd Mode Shape
0
0 100 200 300 400 500 600 700
X (in)
Z-Direction: 3 rd Mode Shape
Y (in)
0
-100
-200
0 200 400 600
X (in)
0
0
200
400
600
X (in)
-200 -100 0 100 200 300
Y (in)
P. Sideris,
Sept. 17, 2012
50
0
0 100 200 300 400 500 600 700
X (in)
Z (in)
150
100
50
0
0 100 200 300 400 500 600 700
X (in)
P. Sideris,
Sept. 17, 2012
SEISMIC TESTING
Shake Table Testing Processing:
• Single Test Analysis
Dynamic characteristics illustrated
• Global Seismic Performance
Effects of different system parameters evaluated
Single Test Analysis:
• Tri-axial Excitation (1979 Imperial Valley EQ ):
• Unloaded Specimen
• Free Sliding at superstructure-to-cap beam connection
Video Recorded Response:
• General view - Test ABC_S1_SC_M2_XYZ
• Lower Pier Joints - Test ABC_S1_SC_M2_XYZ_V05_V11
SEISMIC TESTING
Single Test Analysis:
• Tri-axial Excitation (1979 Imperial Valley EQ ):
SA (g)
Base Excitation
4.5
4.5
DE (AASHTO 2007)
2/3 of DE in Horiz. Direction
MCE
2/3 of MCE in Horiz. Direction
Longit. Dir. - West Table
Longit. Dir. - East Table
Vertical Dir. - West Table
3.0
3.0 30
Lateral Dir. - West Table
Vertical Dir. - East Table
Lateral Dir. - East Table
1.5
1.5
0.0
0.0
0 0.2 0.4 0.6 0.8 1
0 0.2 0.4 0.6 0.8 1
T (sec)
T (sec)
SA (g)
P. Sideris,
Sept. 17, 2012
P. Sideris,
Sept. 17, 2012
7

)
Single Test Analysis:
SEISMIC TESTING
• Tri-axial Excitation (1979 Imperial Valley EQ ):
SEISMIC TESTING
Single Test Analysis:
• Tri-axial Excitation (1979 Imperial Valley EQ ):
Total Accel. - Longit. Dir. (g)
Total Acceleration
1.5
1.5
West Table
West Table
10 1.0
Superstructure - West Side
10 1.0
Superstructure t - West tSide
0.5
0.5
0.0
0.0
-0.5
-0.5
-1.0
-1.0
Limited at ~0.5g
Limited at ~0.55g
-1.5
-1.5
0 10 20 30 40 50 60
0 10 20 30 40 50 60
Time (sec)
Time (sec)
Total Accel. - Lateral Dir.
(g)
Displ. - Lateral Dir. (in)
6
4
2
0
-2
-4
-6
West Cap Beam
Relative Displacement
Displ. - Longitudinal Dir. (in)
Superstructure - West Side
4
0 10 20 30 40 50 60
Time (sec)
6
West Cap Beam
2
0
-2
-4
-6
Superstructure - West Side
0 10 20 30 40 50 60
Time (sec)
P. Sideris,
Sept. 17, 2012
P. Sideris,
Sept. 17, 2012
Single Test Analysis:
• Tri-axial Excitation (1979 Imperial Valley EQ ):
Joint Rocking (rad)
Sliding
(in) / Rotation (rad)
Sliding at Bottom Joint
0.6
X-dir. Sliding
0.4
Y-dir. Sliding
Z-dir. Rotation
0.2
0.0
-0.2
-0.4
-0.6
0 10 20 30 40 50 60
Time (sec)
Rocking at Bottom Joint
0.03
X-dir. Rocking
0.02
Y-dir. Rocking
0.01
0.00
-0.01
-0.02
SEISMIC TESTING
Joint Rocking (rad)
Sliding
(in) / Rotation (rad)
Sliding at 2 nd (from the Bottom) Joint
0.6
X-dir. Sliding
Y-dir. Sliding
0.4
Z-dir. Rotation
0.2
0.0
-0.2
-0.4
-0.6
0 10 20 30 40 50 60
Time (sec)
Rocking at 2
0.03
nd (from the Bottom) Joint
X-dir. Rocking
0.02
Y-dir. Rocking
0.01
0.00
-0.01
-0.02
SEISMIC TESTING
Single Test Analysis:
• Tri-axial Excitation (1979 Imperial Valley EQ ):
Total Base Shear (kips)
40
20
0
-20
Hysteresis in the Y-Direction
Mid-span
-40
-6 -4 -2 0 2 4 6
Relat. Displ. u supY
(in)
Base Shear (kip ps)
20
10
0
-10
Pier Hysteresis in the Y-Direction
East
West
-20
-6 -4 -2 0 2 4 6
Relat. Displ. u cbY
(in)
-0.03
0 10 20 30 40 50
Time (sec)
-0.03
0 10 20 30 40 50
Time (sec)
P. Sideris,
Sept. 17, 2012
P. Sideris,
Sept. 17, 2012
SEISMIC TESTING
Single Test Analysis:
• Tri-axial Excitation (1979 Imperial Valley EQ ):
Joint Rocking
JE0
JE1
JE5
3000
3000
3000
SEISMIC TESTING
Single Test Analysis:
• Tri-axial Excitation (1979 Imperial Valley EQ ):
Joint Sliding
JE0
JE1
JE5
20
20
20
Joint Mo oment (kip-in)
2000
1000
0
-1000
X-Direction
-2000
Y-Direction
-3000
-0.02 -0.01 0 0.01 0.02
Joint Rocking (rad)
Joint Mo oment (kip-in)
2000
1000
0
-1000
-2000
X-Direction
Y-Direction
-3000
-0.02 -0.01 0 0.01 0.02
Joint Rocking (rad)
Joint Mo oment (kip-in)
2000
1000
0
-1000
-2000
X-Direction
Y-Direction
-3000
-0.02 -0.01 0 0.01 0.02
Joint Rocking (rad)
Shear (kips)
Joint
10
0
-10
X-Direction
Y-Direction
-20
-0.5 0 0.5
Joint Sliding (in)
Joint Shear (kips)
10
0
-10
X-Direction
Y-Direction
-20
-0.5 0 0.5
Joint Sliding (in)
Joint Shear (kips)
10
0
-10
X-Direction
Y-Direction
-20
-0.5 0 0.5
Joint Sliding (in)
3000
JW0
3000
JW1
3000
JW5
20
JW0
20
JW1
20
JW5
Joint Moment (kip-in)
2000
1000
0
-1000
-2000
-3000
X-Direction
Y-Direction
-0.02 -0.01 0 0.01 0.02
Joint Rocking (rad)
Joint Moment (kip-in)
2000
1000
0
-1000
-2000
-3000
X-Direction
Y-Direction
-0.02 -0.01 0 0.01 0.02
Joint Rocking (rad)
Joint Moment (kip-in)
2000
1000
0
-1000
-2000
-3000
X-Direction
Y-Direction
-0.02 -0.01 0 0.01 0.02
Joint Rocking (rad)
P. Sideris,
Sept. 17, 2012
Joint Shear (kips)
10
0
-10
X-Direction
Y-Direction
-20
-0.5 0 0.5
Joint Sliding (in)
Joint Shear (kips)
10
0
-10
-20
X-Direction
Y-Direction
-0.5 0 0.5
Joint Sliding (in)
Joint Shear (kips)
10
0
-10
-20
X-Direction
Y-Direction
-0.5 0 0.5
Joint Sliding (in)
P. Sideris,
Sept. 17, 2012
8

)
)
)
)
Single Test Analysis:
• Tri-axial Excitation (1979 Imperial Valley EQ ):
Joint Moment (kip-in)
5000
4000
3000
2000
1000
0
-1000
Y-Direction
Z-Direction
J34
-4 -2 0 2 4
Joint Rocking (rad)
x 10 -3
SEISMIC TESTING
Joint Rocking - Superstructure
J45
Joint Moment (kip-in)
5000
4000
3000
2000
1000
0
-1000
Y-Direction
Z-Direction
-4 -2 0 2 4
Joint Rocking (rad)
x 10 -3
Joint Moment (kip-in)
5000
4000
3000
2000
1000
0
-1000
Y-Direction
Z-Direction
J56
-4 -2 0 2 4
Joint Rocking (rad)
x 10 -3
P. Sideris,
Sept. 17, 2012
SEISMIC TESTING
Single Test Analysis:
• Tri-axial Excitation (1979 Imperial Valley EQ ):
Observations:
• Control of seismic forces
• Moderate Self-centering - Low residual deformations
• Low Damage
• Vertical Excitation (1992 Landers EQ):
• Unloaded Specimen
• Free Sliding at superstructure-to-substructure connection
Video Recorded Response:
• General view - Test_ABC_S1_FF4_M4_Z_e
• Deck mid-joint - Test_ABC_S1_FF4_M4_Z_V13
P. Sideris,
Sept. 17, 2012
SEISMIC TESTING
Single Test Analysis:
• Vertical Excitation (1992 Landers EQ):
SEISMIC TESTING
Single Test Analysis:
• Vertical Excitation (1992 Landers EQ):
Base Excitation
Vertical Acceleration
Joint Rocking at Mid-Span
Vertical Relative Displacement at Mid-span
SA (g)
6.0
2/3 of DE in Horiz. Direction
5.0
2/3 of MCE in Horiz. Direction
Vertical Direction - West Table
4.0
Vertical Direction - East Table
3.0
2.0
1.0
0.0
0 0.2 0.4 0.6 0.8 1
Total Acc. - Vert. Dir. (g
6.0
Limited at 2.0 -2.1g
Mid-span
4.0
East Table
2.0
0.0
-2.0
-4.0
Limited at 2.4 -2.6 g
-6.0
0 5 10 15 20
Midspan - Joint Rocking (ra ad)
0.03
Y-dir. Rocking
0.02
Z-dir. Rocking
0.01
0.00
-0.01
-0.02
-0.03
0 5 10 15 20
Displ. - Vert. Dir. (in)
3.0
Mid-spanp
2.0
1.0
0.0
-1.0
-2.0
-3.0
0 5 10 15 20
T (sec)
Time (sec)
Time (sec)
Time (sec)
P. Sideris,
Sept. 17, 2012
P. Sideris,
Sept. 17, 2012
SEISMIC TESTING
Single Test Analysis:
• Vertical Excitation (1992 Landers EQ):
Joint Moment (kip-in)
6000
4000
2000
0
-2000
-4000
Joint Rocking at Mid-span
J34 J45 J56
Y-Direction
Z-Direction
-0.01 -0.005 0 0.005 0.01
Joint Rocking (rad)
Joint Moment (kip-in)
6000
4000
2000
0
-2000
-4000
Y-Direction
Z-Direction
-0.01 -0.005 0 0.005 0.01
Joint Rocking (rad)
Joint Moment (kip-in)
6000
4000
2000
0
-2000
-4000
Y-Direction
Z-Direction
-0.01 -0.005 0 0.005 0.01
Joint Rocking (rad)
P. Sideris,
Sept. 17, 2012
SEISMIC TESTING
Single Test Analysis:
• Vertical Excitation (1992 Landers EQ):
Observations:
• Control of seismic forces, despite amplification
(resonance)
• High self-centering - Negligible residual deformations
• Low energy dissipation capacity
General System Performance:
• Effect of different factors on system response:
Seismic hazard
Weight/mass
Superstructure-to-cap
beam connectivity
Far-field vs. near-fault
Asynchronous base excitation
Bi-axial vs. tri-axial excitation
P. Sideris,
Sept. 17, 2012
9

SEISMIC TESTING
General System Performance:
• Effect of Asynchronous Base Excitation:
Transverse and vertical peak deformations decrease with
time delay, while residual deformations remain small
Longitudinal direction: Effects not clear
Test Phases: S3b_FF1_XYZ, S3b_FF1DT1_XYZ and S3b_FF1DT2_XYZ
Peak - I
Residual - I
2
0
Peak - AD
Residual - AD
Median Peak - I
Median Residual - I
1
-1
Median Peak - AD
Median Residual - AD
East Pier - Y-Dir.
West Pier - Y-Dir.
5
5
(in)
Rel. Disp.
SEISMIC TESTING
General System Performance:
• Effect of Bi-axial vs. Tri-axial Base Excitation:
Transverse peak deformations are smaller for tri-axial base
excitation
Residual deformations remain small
4.25
Test Phases: S2_FF1_YZ _ and S2_FF1_XYZ
_
Peak - I
Residual - I
2
0
Peak - AD
Residual - AD
Median Peak - I
Median Residual - I
1
-1
Median Peak - AD
Median Residual - AD
East Pier - Y-Dir.
West Pier - Y-Dir.
4.25
(in)
Rel. Disp.
Rel. Disp. (in)
3.75
2.5
1.25
Rel. Disp. (in)
3.75
2.5
1.25
Rel. Disp. (in)
2.125
Rel. Disp. (in)
2.125
0
0 0.05 0.5
Time Lag (sec)
0
0 0.05 0.5
Time Lag (sec)
0
YZ XYZ
Ground Motion Directions
0
YZ XYZ
Ground Motion Directions
P. Sideris,
Sept. 17, 2012
P. Sideris,
Sept. 17, 2012
SEISMIC TESTING
General Observations from Seismic Testing:
Superstructure:
• Survived intense (>>MCE) vertical motions with small
concrete crushing at mid-span joint
• Low PT losses
SEISMIC TESTING
General Observations from Seismic Testing:
Piers:
• Survived severe (e.g., DE, MCE) Far-field and Near-field
motions
• Damage:
• Spalling of reinforcement cover
• Crushing of concrete at bottom joint
• PT losses reached 40% in some cases
Joint at Mid-span – East Face
Joint at Mid-span – East Face
Bottom End – East Pier – Spalled concrete removed
P. Sideris,
Sept. 17, 2012
P. Sideris,
Sept. 17, 2012
General Observations from Seismic Testing:
Piers:
• Damage:
SEISMIC TESTING
West Pier - Bottom Segment
East Side North Side West Side North Side
East Pier - Bottom Segment
East Side North Side West Side North Side
P. Sideris,
Sept. 17, 2012
OVERVIEW
INTRODUCTION
DEVELOPMENT OF HSR SEGMENTAL MEMBERS
EXPERIMENTAL VALIDATION OF HSR BRIDGES:
• Seismic Testing
• Quasi-Static Testing
NUMERICAL MODELING:
• ABAQUS & SAP2000 Modeling
COMPONENT TESTING:
• Response of Strand-Anchor Systems
• Frictional Properties of HSR Joints
CONCLUSIONS & ORIGINAL CONTRIBUTIONS
ACKNOWLEDGEMENTS
P. Sideris,
Sept. 17, 2012
10

Test Specimens:
QUASI-STATIC TESTING
• HSR-SD piers of bridge specimen (Shake Table
Testing)
• Pier were disassembled and some segments were
repaired
• Re-assembly so that:
t
1 st HSR Pier: Original segments only
2 nd HSR Pier: Repaired segments (damage due to dynamic testing)
QUASI-STATIC TESTING
Test Specimens:
Joint 5
PS5
PS4
PS3
PS2
PS1
Joint 4
Joint 3
Joint 2
Joint 1
Joint 0
Gravity Tendon
(For safety reasons,
PVC tubing is used as
a cover)
Actuator
Sandwich
steel plates
Tendon for
gravity
loa ds
Threaded
rods
Steel tubes
P. Sideris,
Sept. 17, 2012
P. Sideris,
Sept. 17, 2012
QUASI-STATIC TESTING
Testing Procedures:
• Two Testing Cases:
Low PT (5 kips per tendon) & Low drift ratio (2.3%)
Design-Level PT (20 kips per tendons) & Large drift ratio
(14.9%)
• Testing Protocol:
Displacement-controlled lateral cyclic loading
Increasing amplitudes - 2 cycles per amplitude
Loading rate: 0.01-0.05 in/sec
• Total gravity load: 44 kips
Applied by two tendons (18 kips each, nominal)
Weight of actuators (4.2 kips each)
QUASI-STATIC TESTING
Recorded Response – Original Pier:
• Low PT Forces – Maximum drift ratio of 2.3%:
North Elevation – Test_ABC_SO_P05_t5_V01
Northwest Corner– Test_ABC_SO_P05_t5_V03
• Regular PT Forces – Maximum drift ratio of 14.9 %:
North Elevation – Test_ABC_SO_P20_t13 t13 V01
Northwest Corner– Test_ABC_SO_P20_t13_V03
P. Sideris,
Sept. 17, 2012
P. Sideris,
Sept. 17, 2012
QUASI-STATIC TESTING
Original Pier :
• Hysteretic Response:
QUASI-STATIC TESTING
Original Pier :
• External Vertical Loading:
All contributions are included
Low PT – 5 kips per Tendon
Design-Level PT – 20 kips per Tendon
Low PT – 5 kips per Tendon
Design-Level PT – 20 kips per Tendon
Lateral Drift Ratio (%)
-2.32 -1.55 -0.77 0 0.77 1.55 2.32
20
Lateral Drift Ratio (%)
40
-15.5 -11.62 -7.75 -3.87 0 3.87 7.75 11.62 15.5
Lateral Drift Ratio (%)
-2.32 -1.55 -0.77 0 0.77 1.55 2.32
Lateral Drift Ratio (%)
-15.5 -11.62 -7.75 -3.87 0 3.87 7.75 11.62 15.5
15
30
46
80
Lateral Force (kips)
10
5
0
-5
-10
Lateral Force (kips)
20
10
0
-10
-20
Vertical Force (kips)
44
42
40
38
36
Vertical Force (kips)
70
60
50
40
-15
-30
34
30
-20
-3 -2 -1 0 1 2 3
Lateral Displacement (in.)
-40
-20 -15 -10 -5 0 5 10 15 20
Lateral Displacement (in.)
-3 -2 -1 0 1 2 3
Lateral Displacement (in.)
-20 -15 -10 -5 0 5 10 15 20
Lateral Displacement (in.)
P. Sideris,
Sept. 17, 2012
P. Sideris,
Sept. 17, 2012
11

)
)
Original Pier :
• Joint Response:
QUASI-STATIC TESTING
Low PT – 5 kips per tendon:
Joint Shear (kip ps)
25
2750
12.5
1375
0
0
-12.5
-1375
-25
-2750
25 2750
12.5
1375
PS5
0
0
PS4
-12.5
-1375
PS3
-25
-2750
25
2750
Joint Moment My (Kip-in)
Joint Moment My (kip (Kip- p-in)
Original Pier :
• Joint Response:
QUASI-STATIC TESTING
Low PT – 5 kips per tendon:
PS5
PS4
PS3
Joint Shear (kip ps)
25
12.5
0
-12.5
-25
-2750
25 2750
12.5
0
-12.5
-25
25
Joint Moment My (Kip-in)
Joint Moment My (Kip- (kip p-in)
2750
1375
0
-1375
1375
0
-1375
-2750
2750
PS2
PS1
12.5
0
-12.5
Joint Moment My (Kip-in)
1375
0
-1375
PS2
PS1
12.5
0
-12.5
Joint Moment My (Kip-in)
1375
0
-1375
-25
-1 -0.5 0 0.5 1
-2750
-0.015 -0.0075 0 0.0075 0.015
-25
-1 -0.5 0 0.5 1
-2750
-0.015 -0.0075 0 0.0075 0.015
Joint Sliding (in)
Joint rocking (rad)
P. Sideris,
Sept. 17, 2012
Joint Sliding (in)
Joint rocking (rad)
P. Sideris,
Sept. 17, 2012
Original Pier :
• Joint Response:
QUASI-STATIC TESTING
Design-Level PT – 20 kips
per tendon:
50
25
0
-25
-50
Joint Moment My (Kip-in)
6250
3125
0
-3125
-6250
Original Pier :
• Joint Response:
QUASI-STATIC TESTING
Design-Level PT – 20 kips
per tendon:
50
25
0
-25
-50
Joint Moment My (Kip-in)
6250
3125
0
-3125
-6250
50 6250
50 6250
PS5
PS4
PS3
PS2
PS1
Joint Shear (kips)
25
0
-25
-50
50
25
0
-25
Joint Moment My (Kip-in) Joint Moment My (kip-i (Kip-in
n)
3125
0
-3125
-6250
6250
3125
0
-3125
PS5
PS4
PS3
PS2
PS1
Joint Shear (kips)
25
0
-25
-50
50
25
0
-25
Joint Moment My (Kip-in) Joint Moment My (kip-i (Kip-in
n)
3125
0
-3125
-6250
6250
3125
0
-3125
-50
-1 -0.5 0 0.5 1
-6250
-0.2 -0.1 0 0.1 0.2
-50
-1 -0.5 0 0.5 1
-6250
-0.2 -0.1 0 0.1 0.2
Joint Sliding (in)
Joint rocking (rad)
P. Sideris,
Sept. 17, 2012
Joint Sliding (in)
Joint rocking (rad)
P. Sideris,
Sept. 17, 2012
Original Pier :
• Decomposition into Joint Sliding and Rocking
Contribution to the response:
Lateral Displacement (in.)
3
2
1
0
-1
-2
Total
Sliding Only
Rocking Only
QUASI-STATIC TESTING
Low PT – 5 kips per Tendon
Lateral Force (kips)
20
15
10
5
0
-5
-10
-15
Rocking Contribution only
Sliding Contribution Only
Original Pier :
• Decomposition into Joint Sliding and Rocking
Contribution to the response:
Lateral Displacement (in.)
20
15
10
5
0
-5
-10
-15
QUASI-STATIC TESTING
Design-Level PT – 20 kips per Tendon
Rocking Contribution only
40 Sliding Contribution Only
Total
Sliding Only 30
Rocking Only
20
Lateral Force (kips)
10
0
-10
-20
-30
-3
0 200 400 600 800 1000 1200 1400 1600
Time (sec)
-20
-3 -2 -1 0 1 2 3
Lateral Displacement (in.)
-20
0 2000 4000 6000 8000 10000 12000
Time (sec)
-40
-20 -15 -10 -5 0 5 10 15 20
Lateral Displacement (in.)
P. Sideris,
Sept. 17, 2012
P. Sideris,
Sept. 17, 2012
12

o
Recorded Response – Original Pier:
• Cycles at 13.5 in:
Lateral Force (ki ips)
QUASI-STATIC TESTING
Experimental Capacity
F max , u max Drift Ratio (%)
40
0 3.87 7.75 11.62 15.5
40
D
=0.17
30 SER=0.42
35
RSE=0.60
20 u max
=13.11
30
F max
=37.56
10
K 25
sec
=2.86
0
20
-10
15
-20
10
-30
5
P05
P20
-40
0
-20 -15 -10 -5 0 5 10 15 20
0 5 10 15 20
Lateral Displacement (in.)
Displacement Amplitude (in.)
Maximum Force (k kips)
Recorded Response – Original Pier:
• Cycles at 13.5 in:
Lateral Force (ki ips)
QUASI-STATIC TESTING
F max , u max Drift Ratio (%)
40
0 3.87 7.75 11.62 15.5
100
0.21
D
=0.17
30
P05
SER=0.42
RSE=0.60
P20
20
80
0.23
u max
=13.11
F max
=37.56
10
K sec
=2.86
60
0.27
0
-10
40
0.33
-20
20
0.47
-30
-40
0
Inf
-20 -15 -10 -5 0 5 10 15 20
0 5 10 15 20
Lateral Displacement (in.)
Displacement Amplitude (in.)
Secant stiffness (kip ps/inch)
Secant Stiffness
Secant Period (se ec.)
P. Sideris,
Sept. 17, 2012
P. Sideris,
Sept. 17, 2012
Recorded Response – Original Pier:
• Cycles at 13.5 in:
Lateral Force (ki ips)
QUASI-STATIC TESTING
Equivalent Viscous Damping
F max , u max Drift Ratio (%)
40
0 3.87 7.75 11.62 15.5
0.5
D
=0.17
30
P05
SER=0.42
RSE=0.60
P20
20
0.4
u max
=13.11
F max
=37.56
10
K sec
=2.86
0.3
0
E D
-10
0.2
-20
ED
0.1
D
-30
2
2
Ksecumax
-40
0
-20 -15 -10 -5 0 5 10 15 20
0 5 10 15 20
Lateral Displacement (in.)
Displacement Amplitude (in.)
Damping Ratio
Recorded Response – Original Pier:
• Cycles at 13.5 in:
Lateral Force (ki ips)
QUASI-STATIC TESTING
Sliding Energy Ratio
F max , u max Drift Ratio (%)
40
0 3.87 7.75 11.62 15.5
1
D
=0.17
30
P05
SER=0.42
RSE=0.60
P20
20
0.8
u max
=13.11
F max
=37.56
10
K sec
=2.86
0.6
0
E D
-10
0.4
-20
ED,
sl
0.2
SER
-30
ED
-40
0
-20 -15 -10 -5 0 5 10 15 20
0 5 10 15 20
Lateral Displacement (in.)
Displacement Amplitude (in.)
Sliding Energy Ratio
(SER)
P. Sideris,
Sept. 17, 2012
P. Sideris,
Sept. 17, 2012
Recorded Response – Original Pier:
• Cycles at 13.5 in:
Lateral Force (ki ips)
QUASI-STATIC TESTING
Relative Self-centering Efficiency
F max , u max Drift Ratio (%)
40
0 3.87 7.75 11.62 15.5
1
D
=0.17
30
P05
SER=0.42
P20
RSE=0.60
20
0.8
u max
=13.11
F max
=37.56
10
K sec
=2.86
0.6
0
E D
-10
0.4
-20
ures ures
0.2
RSE 1
-30
umax
umin
-40
0
-20 -15 -10 -5 0 5 10 15 20
0 5 10 15 20
Lateral Displacement (in.)
Displacement Amplitude (in.)
Relative Self-centering Effi ciency (RSE)
QUASI-STATIC TESTING
Original Pier at Ultimate Amplitude (14.9%):
ABC_SO_P20_t13
ABC_SO_P20_t13
P. Sideris,
Sept. 17, 2012
P. Sideris,
Sept. 17, 2012
13

QUASI-STATIC TESTING
Original Pier:
East Side North Side West Side North Side
• Spalling at
End of Testing:
P. Sideris,
Sept. 17, 2012
QUASI-STATIC TESTING
Observations:
• No failure was observed at ultimate loading: ~15%
drift & vertical force of ~80 kips
• Damage:
Negligible at smaller amplitudes (5% drift
ratio Joint rocking contributes significantly)
Initiation of concrete crushing at ~6% drift, which seems to
saturate/stabilize after ~10%
• PT System:
Negligible or no yielding – Negligible dowel deformations
Some tendons lost 50% of initial PT at drift ratios >8%
P. Sideris,
Sept. 17, 2012
OVERVIEW
INTRODUCTION
DEVELOPMENT OF HSR SEGMENTAL MEMBERS
EXPERIMENTAL VALIDATION OF HSR BRIDGES:
• Seismic Testing
• Quasi-Static Testing
NUMERICAL MODELING:
• ABAQUS & SAP2000 Modeling
COMPONENT TESTING:
• Response of Strand-Anchor Systems
• Frictional Properties of HSR Joints
CONCLUSIONS & ORIGINAL CONTRIBUTIONS
ACKNOWLEDGEMENTS
P. Sideris,
Sept. 17, 2012
NUMERICAL MODELING
Modeling Approaches:
• ABAQUS
General-purpose finite element software
• SAP2000
Structural analysis software
P. Sideris,
Sept. 17, 2012
NUMERICAL MODELING
ABAQUS Finite Element Analysis:
• Modeling of the Quasi-Static Testing Setup
• Geometry and Mesh:
Concrete:
• Solid elements (C3D8R)
• Size: ~ 0.375” – 1”
Mild steel:
• Beam elements (B31)
embedded to concrete
segments
• Size: ~ 0.5”
PT Tendons:
• Truss elements (T3D2)
• Size: 2” and 0.15” at joints
NUMERICAL MODELING
ABAQUS Finite Element Analysis:
• Geometry and Mesh:
P. Sideris,
Sept. 17, 2012
P. Sideris,
Sept. 17, 2012
14

NUMERICAL MODELING
ABAQUS Finite Element Analysis:
• Material Modeling:
Concrete:
• Concrete Damage Plasticity with tension damage
• Post-peak tensile strength based on fracture energy
(0.7lbs/in)
Comp. Stress (psi)
6000
4000
2000
Compressive Behavior
Linear Elastic
Range
0
-0.002 0 0.002 0.004 0.006 0.008
Elastic and Inelastic Strain
Tensile Stress (psi)
Post-peak Tensile Response
600
Linear
500
Bi-linear
400
300
200
100
0
0 0.002 0.004 0.006
Cracking Displacement (in)
70
60
50
NUMERICAL MODELING
ABAQUS Finite Element Analysis:
• Material Modeling:
Mild steel and PT steel:
• Flow plasticity with isotropic hardening
Stress (ksi)
40
30
20
10
0
Mild Steel
0 0.005 0.01 0.015 0.02
Strain
Stress (ksi)
350
300
250
200
150
100
50
0
PT Steel
Analytical (Devalapura
and Tandros 1992)
Simplified
0 0.05 0.1 0.15
Strain
P. Sideris,
Sept. 17, 2012
P. Sideris,
Sept. 17, 2012
NUMERICAL MODELING
ABAQUS Finite Element Analysis:
• Material Modeling:
• Interactions:
General Contact Algorithm
Rigid body constraint for cap
beam and foundation
• Analysis Method:
Explicit dynamics (with mass scaling)
Two steps:
• PT application and Gravity loads
• Lateral displacement (both directions)
Coeff. of Friction
0.25
0.20
0.15
0.10
0.05
000 0.00
Coefficient of Friction
0 500 1000 1500 2000
Contact Pressure (psi)
P. Sideris,
Sept. 17, 2012
NUMERICAL MODELING
ABAQUS Finite Element Analysis:
• Test Results:
Two response phases:
• Sliding-controlled
• Rocking-controlled (plateau)
Lateral Force (kips)
Lateral Drift Ratio (%)
40
-15.5 -11.62 -7.75 -3.87 0 3.87 7.75 11.62 15.5
PlateauInitiation
30
20
10
0
-10
-20
-30
Joint Sliding Initiation
Joint Sliding Initiation
Plateau Initiation
-40
-20 -15 -10 -5 0 5 10 15 20
Lateral Displacement (in.)
P. Sideris,
Sept. 17, 2012
NUMERICAL MODELING
ABAQUS Finite Element Analysis:
• Test Results:
Joint Sliding:
Joint Shea ar (kips)
50
25
0
-25
P20: Joint 0
Numerical
Joint Shea ar (kips)
50
25
0
-25
Numerical
P20: Joint 1
Joint Shea ar (kips)
50
25
0
-25
P20: Joint 2
Numerical
NUMERICAL MODELING
ABAQUS Finite Element Analysis:
• Test Results:
Joint Sliding:
Joint Shea ar (kips)
50
25
0
-25
Numerical
P20: Joint 3
Joint Shea ar (kips)
50
25
0
-25
P20: Joint 4
Numerical
Joint Shea ar (kips)
50
25
0
-25
P20: Joint 5
Numerical
-50
-1 -0.5 0 0.5 1
Joint Sliding (in.)
-50
-1 -0.5 0 0.5 1
Joint Sliding (in.)
-50
-1 -0.5 0 0.5 1
Joint Sliding (in.)
-50
-1 -0.5 0 0.5 1
Joint Sliding (in.)
-50
-1 -0.5 0 0.5 1
Joint Sliding (in.)
-50
-1 -0.5 0 0.5 1
Joint Sliding (in.)
• Findings:
Good Correlation
Numerical instabilities and failure
Large computational time and resources
P. Sideris,
Sept. 17, 2012
P. Sideris,
Sept. 17, 2012
15

NUMERICAL MODELING
Two-node Element Approach:
• Modeling of segment:
Beam-column element for interior part of a segment (end
plastic hinges should be considered for consistency)
“Fiber Springs” to model end regions of segments:
• Two-node inelastic axial and shear elements
• Appropriately distributed over cross-section area
• Oriented in the axial direction of segment
• Connected to interior part (beam-column) with rigid links
• Modeling of PT tendon:
Tension-only truss elements with inelastic behavior
Post-tensioning is applied as initial stress or strain or
temperature change
P. Sideris,
Sept. 17, 2012
NUMERICAL MODELING
Two-node Element Approach:
• Inter-element Constraints:
Rigid links:
• Connect fiber springs to interior part (beam-column) of
segment
• Keep tendons at proper locations at given cross-sections
sections
HSR joints
Interior Beam-
Column Element
Fiber-spring
Fiber-spring
with Lateral
Sliding
Gap Restrainer
against Joint Sliding
Plastic Hinges at Interior
Beam-Column Element
Contact Axial
Element
P. Sideris,
Sept. 17, 2012
NUMERICAL MODELING
Two-node Element Approach:
• Criteria for Distribution of “Fiber Springs”
Equivalent Cross-Section moduli:
N
2 2
EIy
Ez dA
zi EiAi
A
i1
N
2 2
EI
Ey dA
EA Recommendation:
z
yi i i
A
i1
Acceptable Error < 1%
N
EA
EidA
EiAi
A
i1
Maximum distance between fiber springs:
• Resultant axial force should run “smoothly” over the joint
interface & Partial contact should be possible
Symmetric distribution for symmetric sections
N
EA
i i
yi
0 and
L
i1
i
N
i1
EA
i i
zi
0
L
i
P. Sideris,
Sept. 17, 2012
NUMERICAL MODELING
Two-node Element Approach:
• SAP2000:
Segment model:
• Interior: Beam-column elements with end plastic hinges (P x -
M y -M z Interaction)
• Ends: Fiber Springs:
• Consisted of two 2-node Nonlinear Links in series:
• Friction-pendulum link (lateral response)
• Multi-linear plastic spring with kinematic hardening (axial
response)
• Length: 6” for pier segments, and 7.5” for superstructure
segments
P. Sideris,
Sept. 17, 2012
NUMERICAL MODELING
Two-node Element Approach:
• SAP2000:
Segment model:
• Ends:
• Cross-section distribution:
Superstructure
t Pier
NUMERICAL MODELING
Two-node Element Approach:
• SAP2000:
Modeling of PT tendons:
• Truss steel elements with initial axial strain
Material properties:
• Concrete: fc=5800 psi (unconfined)
• Steel: Fy=60 ksi
Frictional Properties:
• Pier Joints: μ=0.1
• Superstructure Joints: μ=0.65
• Superstructure to-Cap beam interface: μ=0.65
P. Sideris,
Sept. 17, 2012
P. Sideris,
Sept. 17, 2012
16

)
(
NUMERICAL MODELING
Two-node Element Approach:
• SAP2000:
NUMERICAL MODELING
Two-node Element Approach:
• SAP2000:
Interior Beam-Column Element
(Extrude View – Element passes through
the centerline of cross-section)
Fiber-Springs
(Modeling of HSR joints )
Hysteretic Element (Fiber-spring)
PT Tendon
Hysteretic Element
(Fiber-spring)
PT Tendon
Fiber-Springs at
Superstructure-to-Cap Beam
Interface
Fiber-Springs
(Modeling of HSR joints )
Friction-Pendulum
Element (Fiberspring)
Interior Beam-Column Element
(Extrude View – Element passes through
the centerline of cross-section)
Friction-Pendulum
Element (Fiber-spring)
P. Sideris,
Sept. 17, 2012
P. Sideris,
Sept. 17, 2012
NUMERICAL MODELING
Two-node Element Approach:
• SAP2000 – Modal Analysis:
Model joint shear stiffness calibrated for unloaded specimen
Experimental
SAP2000
Description
Mode ID Freq. (Hz) ξ Mode # Freq. (Hz)
X-1 3.73 (3.66) 0.061 2 3.23 In-phase pier bending
Y-1 2.82 0.06 1 2.81 In-phase pier bending
Y-2 4.88, 4.18* 011 0.11 3 37 3.7 Out-of-phase pier bending
Z-1 7.13 (7.16) 0.015 4 7.2 Symmetric superstructure vertical bending
Z-2 22.4 0.056 6 15.33 Anti-symmetric superstructure vertical bending
Resulting values for loaded specimen
Experimental
SAP2000
Description
Mode ID Freq. (Hz) ξ Mode # Freq. (Hz)
X-1 2.98 (3.26) 0.073 2 2.43 In-phase pier bending
Y-1 1.97 (1.87) 0.04 1 2.09 In-phase pier bending
Y-2 3.23 0.091 3 2.63 Out-of-phase pier bending
Z-1 5.99 (6.21) 0.022 4 6.44 Symmetric superstructure vertical bending
Z-2 16.8 0.028 6 13.21 Anti-symmetric superstructure vertical bending
NUMERICAL MODELING
Two-node Element Approach:
• SAP2000 – Dynamic Analysis:
Applied Motion:
• 1979 Imperial Valley (Mw=6.5) at Delta Station
• Scaled to DE and SC (MCE horizontal and 2.4xMCE
vertical)
• Tests ABC_S1_FF2_M2_YZ and ABC_S1_SC_M2_YZ
Analysis Method:
• Fast Nonlinear analysis
• Direct integration failed to converge
P. Sideris,
Sept. 17, 2012
P. Sideris,
Sept. 17, 2012
NUMERICAL MODELING
SAP2000 – Dynamic Analysis:
Comparison between Experimental and Numerical Results
East Side (S2) – Transverse Direction (Y) – Relative e Displacement (in)
( )
8
6
4
2
0
-22
-4
-6
-8
8
6
4
2
0
-2
-4
-6
-8
Rel. Displ. – Deck - East
ABC_S1_FF2_M2_YZ
Experimental
SAP2000
0 20 40 60
ABC_S1_SC_M2_YZ
Experimental
SAP2000
0 20 40 60
Time (sec)
West Side (S7) – Transverse Direction (Y) – Relative e Displacement (in)
p( )
p( )
8
6
4
2
0
-2
-4
-6
-8
8
6
4
2
0
-2
-4
-6
-8
Rel. Displ. – Deck - West
ABC_S1_FF2_M2_YZ
Experimental
SAP2000
0 20 40 60
ABC_S1_SC_M2_YZ
Experimental
SAP2000
0 20 40 60
Time (sec)
P. Sideris,
Sept. 17, 2012
NUMERICAL MODELING
SAP2000 – Dynamic Analysis:
Comparison between Experimental and Numerical Results
Displacement
p( )
(in)
East Pier – Transverse
p( )
Direction (Y) – Relative
8
6
4
2
0
-2
-4
-6
-8
8
6
4
2
0
-2
-4
-6
-8
Rel. Displ. – East Pier
ABC_S1_FF2_M2_YZ
Experimental
SAP2000
0 20 40 60
ABC_S1_SC_M2_YZ
0 20 40 60
Time (sec)
Experimental
SAP2000
Displacement (in)
West Pier – Transverse ( ) Direction (Y) – Relative
8
6
4
2
0
-2
-4
-6
-8
8
6
4
2
0
-2
-4
-6
-8
Rel. Displ. – West Pier
ABC_S1_FF2_M2_YZ
Experimental
SAP2000
0 20 40 60
ABC_S1_SC_M2_YZ
Experimental
SAP2000
0 20 40 60
Time (sec)
P. Sideris,
Sept. 17, 2012
17

NUMERICAL MODELING
SAP2000 – Dynamic Analysis:
Comparison between Experimental and Numerical Results
East Side (S2) – Transverse Direction (Y) – To otal Acceleration (g)
3.0
2.0
1.0
0.0
-1.0
-2.0
-3.0
3.0
2.0
1.0
0.0
-1.0
-2.0
-3.0
Total Acc. – Deck - East
ABC_S1_FF2_M2_YZ
SAP2000
Experimental
0 20 40 60
ABC_S1_SC_M2_YZ
SAP2000
Experimental
0 20 40 60
Time (sec)
West Side (S7) – Transverse Direction (Y) – To otal Acceleration (g)
3.0
2.0
1.0
0.0
-1.0
-2.0
-3.0
3.0
2.0
1.0
0.0
-1.0
-2.0
-3.0
Total Acc. – Deck - West
ABC_S1_FF2_M2_YZ
SAP2000
Experimental
0 20 40 60
ABC_S1_SC_M2_YZ
SAP2000
Experimental
0 20 40 60
Time (sec)
P. Sideris,
Sept. 17, 2012
NUMERICAL MODELING
SAP2000 – Dynamic Analysis:
Comparison between Experimental and Numerical Results
Mid-span – Vertical Direction (Z) – Relative Displacement (in)
1.0
0.5
0.0
-0.5
-1.0
1.0
0.5
0.0
-0.5
-1.0
Rel. Vert. Displ. – Midspan
ABC_S1_FF2_M2_YZ
Experimental
SAP2000
0 20 40 60
ABC_S1_SC_M2_YZ
Experimental
SAP2000
0 20 40 60
Time (sec)
Mid-span – Vertical Direction (Z) – Total Acc celeration (g)
6.0
4.0
2.0
0.0
-2.0
-4.0
-6.0
6.0
4.0
2.0
0.0
-2.0
-4.0
-6.0
Total Acc. – Midspan
ABC_S1_FF2_M2_YZ
SAP2000
Experimental
0 20 40 60
ABC_S1_SC_M2_YZ
SAP2000
Experimental
0 20 40 60
Time (sec)
P. Sideris,
Sept. 17, 2012
NUMERICAL MODELING
SAP2000 – Dynamic Analysis:
• Observations:
Good for preliminary analysis of systems dominated by joint
rocking, particularly at lower intensities
Poor performance for systems that dominated by joint
sliding. Larger discrepancies occur at larger intensities
P. Sideris,
Sept. 17, 2012
OVERVIEW
INTRODUCTION
DEVELOPMENT OF HSR SEGMENTAL MEMBERS
EXPERIMENTAL VALIDATION OF HSR BRIDGES:
• Seismic Testing
• Quasi-Static Testing
NUMERICAL MODELING:
• ABAQUS & SAP2000 Modeling
COMPONENT TESTING:
• Response of Strand-Anchor Systems
• Frictional Properties of HSR Joints
CONCLUSIONS & ORIGINAL CONTRIBUTIONS
ACKNOWLEDGEMENTS
Conclusions
P. Sideris,
Sept. 17, 2012
STRAND-ANCHOR SYSTEM
System Definition:
• Unbonded monostrand
+
Wedge-anchors at its ends
Test Setup:
• Strand-Anchor system
at Universal Testing Machine
Specimen Variations:
• 0.5” and 0.6” diameter
monostrands
Testing Program:
• Quasi-static mixed
force/displacement-controlled
load application
P. Sideris,
Sept. 17, 2012
STRAND-ANCHOR SYSTEM
Test Results:
• Three major observations:
Premature fracture of monostrands
Successive (≠ simultaneous) wire fracture
Loading ≠ unloading (and Reloading) stiffness and smaller
than that of monostrand itself
Force (kips)
50
40
30
Loading
Branch
20
10
Unloading-Reloading
Branches
Wire
Fracture
0
0 0.5 1 1.5 2 2.5 3 3.5
Displacement (in)
P. Sideris,
Sept. 17, 2012
18

Test Results:
STRAND-ANCHOR SYSTEM
• Premature Failure
Ultimate Stress (ksi)
280
260
240
220
Strength reduction up to 10%
Fracture strains vary between 0.015 – 0.04 (

HSR JOINT FRICTIONAL PROPERTIES
Specimen Description:
• 2”x2”x2” concrete cubes
• Axially compressed
• Displacement is applied to central cube
Test Setup:
HSR JOINT FRICTIONAL PROPERTIES
Specimen Description:
Test Setup:
Sliding
interface
P. Sideris,
Sept. 17, 2012
P. Sideris,
Sept. 17, 2012
HSR JOINT FRICTIONAL PROPERTIES
Specimen Configurations:
• Interface type:
Dry concrete
Concrete-silicone
• Axial compression:
200 psi, 500 psi and 750 psi
• Sliding amplitude and velocity:
< 0.35” and < 3 in/sec
HSR JOINT FRICTIONAL PROPERTIES
Test Results:
• Dry Concrete Interface:
CoF
Coeff. of Friction for velocity

Test Results:
• Concrete-Silicone Interface:
Permanent CoF C
HSR JOINT FRICTIONAL PROPERTIES
Coeff. of Friction for velocity

CONCLUSIONS
Numerical models are required to provide reliable predictions
of the response of HSR members
Response of individual unbonded monostrands considerably
differs from strand-anchor systems
Silicone material significantly affects the HSR joint frictional
properties
ACKNOWLEDGEMENTS
Federal Highway Administration of the U.S.
Department of Transportation
Bodossaki Foundation
Alexander S. Onassis Public Benefit Foundation
SEESL personnel (Particularly Ms. M. Anagnostopoulou,
Structural and Test Engineer)
UB’s CCR (Particularly Dr. L. Shawn Matott)
Mr. Joe Salvadori (DSI), Dr. Curt Haselton (CSU,
Chico), Mr. David Welch (Undergraduate, University at
Buffalo)
P. Sideris,
Sept. 17, 2012
P. Sideris,
Sept. 17, 2012
Thank you!!!
Questions?
P. Sideris,
Sept. 17, 2012
22