use of precast members for accelerated bridge construction...
Post on 29-Mar-2018
232 Views
Preview:
TRANSCRIPT
6th International Bridge Conference 1
Bijan KhaleghiConcrete Specialist
Washington State Department of TransportationBridge and structures Office
Olympia, Washington
Use of Precast Members For Accelerated Bridge Construction
in Washington State
6th International Bridge Conference 2
Advantages:• Precasting Accelerates Bridge Construction • Precasting Eliminates Concrete Forming,
Casting and Curing in the Jobsite• Precasting Improves Work zone Safety
Concerns:• Seismic Design and Detailing Guidelines• Monolithic Seismic Resistant Connections• Construction Equipment and Cost• Construction Tolerances
Precast Bridges
6th International Bridge Conference 3
Major Faults in Major Faults in Puget SoundPuget Sound
Seismic Design in Washington State
6
6
8 79
1520
30
25
25
30
10
Everett
Seattle
TacomaOlym
pia
6th International Bridge Conference 4
KOBE NORTHRIDGE LOMA PRIETA
Year 1995 1994 1989Magnitude 6.9 6.7 7.1Peak Acceleration (a) 0.80 1.00 0.60
Depth of Rupture (km)
14.3 18.0 19.0
Duration (sec.) 11 9 8Bridge Damage($ x Millions)
$6,700 $300 $1,500
NISQUALLY20016.8
52.0
$5
0.25
10
Recent EarthquakesComparison of Seismic Events
6th International Bridge Conference 5
Seismic Design
Fix Connection Double-Curvature
Fixed
Fixed
Fixed
Pinned
Moment DiagramShape
Moment Diagram
Shape
Hinge Connection Single-Curvature
EQ Force
EQ Force
6th International Bridge Conference 6
SEISMIC DESIGN SEISMIC DESIGN RESPONSE SPECTRARESPONSE SPECTRA
..11
.2.2.3.3.4.4.5.5.6.6
AC
CE
LE
RA
TIO
NA
CC
EL
ER
AT
ION
PERIODPERIOD
11 22 33 44
pile supported footingpile supported footing
shaft foundationshaft foundation
(sec.)(sec.)
(g)
(g)
Spread Footing foundationSpread Footing foundation
T=2mk for SDOF
undamped free vibration.
PILE FOUNDATIONPILE FOUNDATIONSHAFT FOUNDATIONSHAFT FOUNDATION SPREAD FOOTINGSPREAD FOOTING
6th International Bridge Conference 7
Key Factors in Seismic Design
Precast Girder
Semi Integral End Pier
Backfill
Precast Girder
Expansion joint
Elastomeric Bearing pad
Seat width for seismic movement
Girder stop to restrain transverse movement Gap for
seismic movement
L-shape
Abutment
Ductile Connection
Joint-less Superstructure
CIP Slab
Shaft
In-Span Hinge
Pile-to-pile cap Connection
6th International Bridge Conference 8
Seismic Design at Intermediate Piers(C-I-P or Precast)
Seismic Elastic Forces
ME/VE
ME/VE
ME/VE
ME/VE
ME/VE
ME/VE
Center of Mass
1.3MP/VP
1.3MP/VP
1.3MP/VP
1.3MP/VP
1.3MP/VP
1.3MP/VP
Plastic Hinging Forces
MDesign = ME/R
Response Spectrum Analysis
6th International Bridge Conference 9
Fixed Intermediate DiaphragmCL Column and Diaphragm
Extended Strands for M+ Connection
Precast Girder
cn fbdV '38.0≤
Column Connections
Plastic Hinging
M = MP + VP h
uyvfn PfAV 75.0+=Construction Joint in Column
Precast Girderc.g. of
superstructure
yh
c
c
gs f
fAA '
145.0
−≥ρ
yh
cs f
f '12.0≥ρ
Confinement Reinforcement
Plastic Hinging
MP & VP
CIP Slab
6th International Bridge Conference 10
2001 India Earthquake
Seismic Resistant Connections(Monolithic Connections)
2001 Nisqually Earthquake
Monolithic Connection, WA
6th International Bridge Conference 11
Elevation
Design for ContinuityJoint less Superstructure
400 – 600 ft
Kobe, Japan (1995)
6th International Bridge Conference 12
Positive Moment ConnectionStrand Anchor Detail
1"
1"1"
CL GirderPrestressed Girder
Strand Anchor or ChucksPier Cap
CIP Diaphragm
1’-6”
1”x 7”φ Anchor Plate
Bonded Strands
Strand Anchor
CL Girder
Alternate 1 or 2
Alternate 3
6th International Bridge Conference 13
MC = Lesser elastic or plastic hinging moment of column, ft-kipsMSIDL= Moment due to traffic barriers and sidewalk, ft-kipsVC = Lesser of elastic or plastic hinging shear of column, kipsh = Distance from top of column to centroid of superstructure, ftd = Distance from top of slab to centroid of extended strands, inNC = Number of columns in the pierNg = Number of prestressed girders in the pier APS = Area of each extended strands, in2
fPS = Ultimate strength of prestressing strands, ksik = Span coefficient (k=0.5 for L1 = L2, k = 0.67 for L1 = 2L2)
xdxfAkx
NNMxhVMN
PSPSg
CSIDLCCPS 9.0
)(12 −+=
Extended Strands (Fixed intermediate Diaphragm)
6th International Bridge Conference 14
Extended Strands for Positive Moment Connection(Fixed intermediate Diaphragms)
Type of GirderNumber of girders, NgColumn diameter (ft)Number of columns, Ncplastic hinging moment, MPColumn plastic shear, VpColumn Elastic moment, ME Column EQ Elastic shear, VETop of column to c.g. of superstSIDL Moment per girderTop of slab to c.g. of strandsArea of each strand, ANumber of extended strandsStrand Extension Alternative
SE 8th I/CW58G
461
96301067
124201333
817862
0.15312
3
Methow RiverW83G
752
6250887
16110
227011.821090
0.2176
1 or 2
Precast Girder ProjectsHPC
ShowcaseW74G
542
4840494
8240
5678.167194
80.750.217
51 or 2
W74G542
4920
4658060
7629.16720475
0.2176
1 or 2
Bone River
Jenkins Creek W74G
93.53
3660
3436280
5719.16718875
0.2174
1 or 2
6th International Bridge Conference 15
WSDOT Standard Prestressed Girders
W50G W58GW42G W74G
2’-1”
3’-7”
6’-1
1/2 ”
2’-1” 2’-1”
4’-1
0”
1’-8”2’-1”
4’-2
”1’-8”
1’-3”3’
-6”
NSCHSC
70 90 110 13080 100 125 145
Span Capability (ft) 1995
80% of All New Bridges are Precast Girders
6th International Bridge Conference 16
STANDARD WIDE FLANGE GIRDERS
W95G W83G
WF74GWF42G
3’-2”
4’-1”
WF50G WF58G
Span Capability, ftWF42GWF50GWF58GWF74G
125140165
110
W83GW95G
180190
6th International Bridge Conference 17
WF42G vs. W42G
40
60
80
100
4 6 8 10 12 14 16Girder Spacing (ft)
Span
Len
gth
(ft)
WF42G
W42G
WF58G vs. W58G
60
80
100
120
140
4 6 8 10 12 14 16
Girder Spacing (ft)
Spa
n Le
ngth
(ft)
WF58G
W58G
WF74G vs. W74G
80
100
120
140
160
4 6 8 10 12 14 16Girder Spacing (ft)
Spa
n Le
ngth
(ft)
WF74G
W74GSpan Capability
Comparison
6th International Bridge Conference 18
Bridge Superstructure ReplacementGirder Efficiency
Existing Bridge (1992 Design)15 – W74G Girders
New Bridge (2003 Design)8 – WF74G Girders
• fc = 10.0 ksi• fci = 7.5 ksi• 0.6” φ Strands
• fc = 6.0 ksi• fci = 5.0 ksi• 0.5” φ Strands
6th International Bridge Conference 19
WSDOT TRAPEZOIDAL TUB GIRDERS1'-6"
4½"
SYMM. ABOUT ¢ TUB GIRDER
TRAPEZOIDAL TUB SECTION
71
Span Capability, ft
U54G4
U66G4U78G4UF60G4
155170150
130
UF72G4UF84G4
165185
6th International Bridge Conference 20
STANDARD SPLICED I-GIRDERS
W95PTGWF74PTG W83PTG
4'-2¾“
1.020 (3'-4 3/8“)
7 7/8”
Span Capability, ft
WF74PTGW83PTGW95PTG
185 205200 235
165 180GIRDER PT Before PT After
PCI Award
6th International Bridge Conference 21
Precast HSC Spliced I-Girders(Riverside Bridge)
Precast SuperstructureHinge Connections at Piers
PCI Award
6th International Bridge Conference 22
STANDARD HSC SPLICED U-GIRDERS
TRAPEZOIDAL TUB SECTION
SYMM. ABOUT ¢ TUB GIRDER
VARIES 4'-0" TO 10'-0"
7
1
10"
VA
RIE
S 2'
-6"
TO
6'-6
"
4½"
1'-6"
Span Capability, ftU54PTG6U66PTG6U78PTG6
165190
145
PCI Award
6th International Bridge Conference 23
Precast Spliced Girder- Fixed Diaphragm
S. 38th Street Bridge
6th International Bridge Conference 24
Precast Stay-in-Place Deck Panel
S. 38th Street Bridge
6th International Bridge Conference 25
Precast Spliced Girder- Fixed Diaphragm
(Green River Bridge)Precast SuperstructureHinge Connections at Piers
6th International Bridge Conference 26
YES NO
Num
ber o
f Sta
tes 25 –
20 –
15 –
10 –
5 –
0 –
22 (82%)
5 (18%)
DomesticYES NO
Num
ber o
f Cou
ntrie
s
10 –
8 –
6 –
4 –
2 –
0 –
6 (100%)
0 (0%)
Foreign
PCI Seismic Design Survey
SURVEY: Use of Precast Members in Bridge Construction
Superstructure:
6th International Bridge Conference 27
YES NO
Num
ber o
f Sta
tes 25 –
20 –
15 –
10 –
5 –
0 –
19 (76%)
6 (24%)
DomesticYES NO
Num
ber o
f Cou
ntrie
s
10 –
8 –
6 –
4 –
2 –
0 –
2 (33%)
4 (67%)
Foreign
Substructure:
SURVEY: Use of Precast Members in Bridge Construction
PCI Seismic Design Survey
6th International Bridge Conference 28
• Lack of Design and Detailing Guidelines• Availability of Construction equipments• Lack of construction specifications • Long-term performance & maintenance concerns• Connection Details Meeting Seismic Requirements• Cost competitive with C-I-P • Cost of Fabrication and Shipping • Site and Soil Condition for Crane Load, etc• Need for Small Demonstration Projects
Difficulties in using Precast BridgesPCI Seismic Design Subcommittee Survey
6th International Bridge Conference 29
Precast SubstructuresPCI Seismic Design Subcommittee
State of the Practice Repost outlines1. Introduction 2. Seismic Criteria 3. Seismic Analysis 4. Structural System Considerations5. Connection Details6. Current Practice7. Good detailing practices 8. Design Examples 9. Applicable Current Research
6th International Bridge Conference 30Precast Column
Precast Column
Precast Column Erection Support
Column reinforcement
Precast Girders
Precast Column
Cast-In-Place Shaft
Cast-In-Place Bent Cap
Confinement Zones
Construction Joint
Precast Column Erection Support
Precast Column on Shaft
6th International Bridge Conference 31
Precast Column on Spread Footing
6th International Bridge Conference 32
CIP superstructure
CIP Footing
Support Pad
Precast Column
Precast Column Erection Support
Column reinforcement
Precast Slanted Column on Spread Footing
6th International Bridge Conference 33
Precast Slanted Column on Spread Footing
6th International Bridge Conference 34
Reduced Scale Test Specimen
Column Test for Seismic (UNR)
6th International Bridge Conference 35
Precast ColumnCompleted Precast System with monolithic connections
Section A
Plan (Precast Bent Cap) Precast Column
Precast Column Erection Support
Column reinforcement
Seat for Precast Bent Cap (12” Min)
Joint reinforcement
A
Precast System (monolithic connections)
6th International Bridge Conference 36
Cast-in-place Diaphragm
Cast-in-place Slab
Support Pad
Precast Column
Precast Bent Cap
Confinement Zones
Precast Column
Cast-In-Place Shaft
3” thick
Rubber Pad
Precast System (monolithic connections)
6th International Bridge Conference 37
Precast Column
Cast-In-PlaceShaft
Cast-in-place Diaphragm
Support Pad
Precast Column
Precast Bent CapConfinement
Zones
Cast-in-place Slab
3” thick
Rubber Pad
Precast System –Precast Deck (monolithic connections)
6th International Bridge Conference 38
Numerical Application (Precast column to Precast Bent cap)
Bottom of Column
Top of Column
Column Diameter, ft 6 4
Axial Load, kips 1945 1869Seismic Elastic Moment, ft-kips 22530 21360
Reduced Moment, ft-kips 4506 4272
Reinforcement Ratio 1% 3.75%
Resistance Factor 0.75 0.68Plastic Hinging Moment, ft-kips 8406 8390
Top of Column
6 (4 at Recess)1869
18360
3672
3.25%
0.68
7212
6th International Bridge Conference 39
Ongoing Research With University of WA
6” φ Hole in Crossbeam for
1-3/8” φ –150 ksi Bar Tendons
PLANELEVATION
6th International Bridge Conference 40
Inverted Precast T-BeamHole for Extended strands and #7 bars
CIP Slab
Ongoing Research With University of WA
6th International Bridge Conference 41
Precast Pedestrian/Bike BridgePrecast SuperstructurePrecast ColumnFixed Connections at Piers
80’-0” 80’-0”
Precast Variable Depth Tub Precast Column
Cast-in-place Ductile joints
6th International Bridge Conference 42
Conclusions - 1Precast bridges are effective system for Accelerated bridge construction.
Monolithic connections meeting seismic Design and Detailing requirements shall be considered
Extended strands in bottom flange provide positive flexural capacity to resist EQ Forces
Construction Tolerances shall be Considered
Long-term performance & maintenance concerns
6th International Bridge Conference 43
Conclusions – 2Lack of Design and Detailing Guidelines
Lack of construction specifications
Availability of Construction equipments
Cost competitiveness with C-I-P Alternative
Fabrication and Shipping Cost
Site and Soil Condition for Crane Load and Placement
Need for Demonstration Projects
top related