CLEARWATER BEACH SPUR CONNECTOR CABLE-STAYED BRIDGE

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CLEARWATER BEACH SPUR CONNECTOR CABLE-STAYED
BRIDGE
Presented by Hisham N. Sunna, Ph.D., P.E. Ayres
Associates
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Agenda

• Bridge Configuration
• Deck Section and Pylon
• GTSTRUDL Model
• Stay Cables
• Post-tensioining
• Losses Due to Creep, Shrinkage and Relaxation
• Result Comparisons
• Element Stresses
• Construction Phases
• Cable Loss
• Conclusions

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Bridge Configuration
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Bridge Deck Section

• Symmetric
• About Centerline

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Pylon
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GTSTRUDL Model

• 1639 Joints
• 318 Members
• 12 Isoparametric Cable Elements
• 2 Nonlinear Spring Elements
• 1460 SBHQ6 Elements

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Model Elevation
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Model Top View
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Model Isometric View
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Support Conditions
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Stiffness Matrix for Drilled Shafts
(From FB-Pier
Program Output)

• STATUS SUPPORT 1618 1619
• JOINT 1618 1619 RELEASES FORCE KFX 0.2877E03 KFY
  0.1886E05 KFZ 0.2493E03 -
• KMX 0.3320E08 KMY 0.5716E00 KMZ 0.3456E08

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GTSTRUDL Statements for Initial Cable Prestress

• DEFINE CABLE NETWORK 12
• INCLUDE ELEMENTS 'CABLE12'
• ATTACH JOINTS 1602 1631
• INITIAL TENSION T0 244.0 JOINTS 1602
• CONVERGENCE RATE 1.0
• CHORD LENGTH 188.69
• ADJUST LENGTHS
• END
• CABLE ANALYSIS DATA
• CONVERGENCE TOLERANCE GEOMETRY 0.01
• MAXIMUM NUMBER OF GEOMETRY ITERATIONS 30
• MAXIMUM NUMBER OF EQUILIBRIUM ITERATIONS 50
• LOAD 12
• END
• PERFORM CABLE PRESTRESS ANALYSIS

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Longitudinal Tendon Profiles
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PT Equivalent Loads (per ½ Deck)
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 Tendon L1 Profile
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Tendon L1 Stresses
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Tendon L1 Equivalent Loads
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 Tendon L2 Profile
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Tendon L2 Stresses
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Tendon L2 Equivalent Loads
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 Tendon L3 Profile 
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Tendon L3 Stresses
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Tendon L3 Equivalent Loads
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GTSTRUDL Statements for Addition of
Post-tensioning Equivalent Load

• FORM LOAD 'DEAD PLUS STAY' FROM 12 1.0
• LOAD LIST 12 'DEAD PLUS STAY'
• NONLINEAR EFFECTS
• GEOMETRY MEMBERS 1 TO 4
• CONVERGENCE TOLERANCE EQUILIBRIUM 0.5
• MAXIMUM NUMBER OF CYCLES 200
• NONLINEAR ANALYSIS
• LIST DISPLACEMENTS JOINTS 1 TO 146 1618 TO 1637
• LIST REACTIONS
• SECTION FR NS 2 0.5 1.0
• LIST SECTION FORCES
• LIST ELEMENT FORCES ELEMENTS 'CABLE1' TO
  'CABLE12'
• CHANGES
• FORM LOAD 12 FROM 3 0.25
• ADDITIONS
• MAXIMUM NUMBER OF CYCLES 50
• LOAD LIST 12
• NONLINEAR ANALYSIS CONTINUE

• FORM LOAD 12 FROM 3 0.25
• ADDITIONS
• MAXIMUM NUMBER OF CYCLES 100
• LOAD LIST 12
• NONLINEAR ANALYSIS CONTINUE
• CHANGES
• FORM LOAD 12 FROM 3 0.25
• ADDITIONS
• MAXIMUM NUMBER OF CYCLES 150
• LOAD LIST 12
• NONLINEAR ANALYSIS CONTINUE
• CHANGES
• FORM LOAD 12 FROM 3 0.25
• ADDITIONS
• MAXIMUM NUMBER OF CYCLES 50
• LOAD LIST 12
• NONLINEAR ANALYSIS CONTINUE
• LOAD LIST ALL
• CREATE LOAD COMBINATION 'DELTA PT' SPECS 12 1.0
  'DEAD PLUS STAY' -1.0

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Creep, Shrinkage, and Temperature Effects on Stay
Forces
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Creep, Shrinkage, and Temperature Effects on Stay
Forces
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Temperature Change Loading to Simulate Axial Creep

• LOAD 6 'CREEP'UNITS FAHRENHEITJOINT
  TEMPERATUREJOINTS 1 TO 1617 TEMPERATURE CHANGE
  -116.37MEMBER TEMPERATURE LOADS3 4 AXIAL
  -86.40729 TO 320 AXIAL -116.37

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Lateral Restraint and Creep and Shrinkage
Analysis Using Temperature Loads

• Issue
• Stress artifacts due to lateral deformations
  caused by the temperature loading.
• Workaround
• Release lateral restraint at one end for analysis
  of creep and shrinkage. The lateral restraint is
  restored to the model to investigate lateral
  loading (wind loads)

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Deflection Due to Dead Load Plus Stay Force
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Incremental Deflection Due to Post Tensioning
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Deflection Due to Dead Load, Stay Forces, and
Post-tensioning
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Deflection Due to DL, LL, Stay Force, and PT

After all losses (10000 days)
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Deck Deflections
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(No Transcript)
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Principal Stress Contours (S1, Top) Due to Dead
Load Plus Stay Force
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Principal Stress Contours (S1, Top) Due to Dead
Load, Stay Force, and Post-tensioning
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Principal Stress Contours (S1, Top) Due to
Total Loads
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Principal Stress Contours (S2, Top) Due to Dead
Load Plus Stay Force
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Principal Stress Contours (S2, Top) Due to Dead
Load, Stay Force, and Post-tensioning
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Principal Stress Contours (S2, Top) Due to
Total Loads
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Phase 1 Construction
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Phase 1 Stress Cables 5 and 6
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Phase 1 Stress Cables 3 and 4
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Eigenvalue Analysis

• Mode Shapes
• Vertical Single Peak
• Lateral Tower Displacement
• Tower Lean Back
• Deck Twist
• Tower Twist
• Vertical Double
• etc.
• Deck Lateral Sway Eliminated from Low Modes by
  Supporting Deck Laterally at End Bridge!!

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Cable Replacement and Loss of Cable
(ref. PTI)

• Cable Exchange
• 1.2 DC 1.4 DW 1.5(LLIM) Cable Exchange
  Forces (can reduce live load in the area of the
  cable under exchange)
• Strength Limit State, f 0.8 suggested
• Loss of Cable
• 1.2 DC 1.4 DW 0.75(LLIM) Cable Loss
  Dynamic Forces. Extreme Limit State Event f0.9
  suggested
• Dynamic Force Due to Sudden Cable Fracture is of
  magnitude equal TWICE the static force in the
  cable and acts at both top and bottom anchorages.
  

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Loss of Cable 1 (Vertical Scale Exaggerated 10
times)
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Loss of Cable 12 (Vertical Scale Exaggerated 20
times)
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CLEARWATER BEACH SPUR CONNECTOR CABLE-STAYED
BRIDGE

• Questions?