2014 NATIONAL BRIDGE PRESERVATION PARTNERSHIP CONFERENCE
James J. Jacobsen, P.E.
District Structures Maintenance Office
Tampa, Florida
1 April 24, 2014
Florida Department of
TRANSPORTATION
Special Considerations for Maintenance of the Sunshine Skyway Bridge
Presentation Outline
• Sunshine Skyway Bridge Overview
• Proactive Maintenance Program: Skyway Preservation Committee
• Post Tensioning Protection
• Improved Inspection and Maintenance Access
• Bridge Health Monitoring
• Strategy for a 100-year Bridge Life
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Sunshine Skyway Bridge
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Sunshine Skyway Bridge Location
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Skyway Bridge History • In May 1980, a major ship impact caused the south
bound main span of the original bridge to collapse.
• A signature replacement bridge was envisioned.
• After a 5 year construction period, the bridge was opened to traffic in April 1987.
• The bridge was re-dedicated in 2005 as the “Bob Graham Sunshine Skyway Bridge” as the former Florida Governor had the vision to build this signature bridge.
• Owned and Maintained by the Florida Department of Transportation
• Asset Maintenance Contracted since 2004
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Looking south
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Looking North
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MAIN SPAN UNIT
•Post-Tensioned Precast Segmental Box
•42 Continuous Stay Cables, 21 per Pylon
•Total Length: 4,000 ft
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•Post-Tensioned Precast Segmental Boxes
•Post-Tensioned Precast Segmental Columns
• Length: 2,430 ft each
HIGH LEVEL
APPROACH HIGH LEVEL
APPROACH
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LOW LEVEL TRESTLE SPANS
LOW LEVEL TRESTLE SPANS
Shldr.
Lane
Lane
Shldr.
Shldr.
Lane
Lane
Shldr.
Cast In Place Deck on Prestressed Concrete Beams
Total Length: 13,000 ft
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High level approach
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High Level Approach Column and Dolphin
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Proactive Maintenance Program
• Major Challenge: Preserve the Investment
• Response: Skyway Preservation Committee
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Total Cost Per Year to Maintain
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Major Maintenance Challenges
•Corrosive Environment
•Three types of bridges in one
•Access for Maintenance
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Skyway Preservation Committee
The Preservation Committee exists to provide a forum whereby a select group of specialists come together twice per year to discuss a wide variety of issues that affect the current and long term health of the Skyway Bridge.
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Sample Skyway Preservation Committee Meeting Agenda Items
• Recently completed repair contracts
• Accelerometers on Stay Cables
• Remove Anchorage Covers
• Stay Cable Tension Testing
• Median Interior Maintenance
• Corrosion Prevention (water line and foundation)
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Post Tensioning Protection
• Five Strategies: New Direction for Florida: PT Bridges (2002)
1. Enhanced PT system
2. Multiple tendon Paths
3. Fully grouted tendons
4. Water tight bridge
5. Multiple layer anchor protection
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Where could water enter?
• Closure pour cracking
• PT anchor pour-backs
• Raised median
• Segment joints (dry and epoxy coated)
• Cracked Polyethylene Ducts
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Where could water enter?
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Sealing the Raised Median Barrier with Polyurea
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Cable Stay / Median Barrier
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Segmental Bridge Deck
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2013 Deck Sealing Test Area Methyl Methacrylate
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2013 Deck Sealing Test Area Methyl Methacrylate
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Polyethylene Ducts
• All External PT ducts had been wrapped with heat shrink sleeves by 2006.
• Ongoing maintenance includes localized repairs by asset maintenance forces.
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Localized Heat Shrink Duct Wrap Repair
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Special Inspection of Post Tension Systems
• The Post Tension System is a critical item to inspect and ensure proper performance
• Voids and segregated grout must be detected and corrected to ensure maximum life of post tensioning system
• Special inspection methods are needed beyond the routine visual inspection
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Typical External Tendon Cross Section
High Density
Polyethylene Duct
Strand
Cement grout
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Post Tensioned Tendon Inspection State of the Art
• No single test method is able to effectively inspect and detect tendon voids and corrosion
• Current methods can be expensive and time consuming: Main Magnetic Flux
• Several methods may need to be combined to get better results
• The FDOT is supporting new development in non destructive testing
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Cable Stay Repainting
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Cable Stay Repainting
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High Level Approach Bearing Inspection
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High Level Approach Maintenance
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Transition Pier from Single to Dual Box Sections
Typical High Level Approach
34
Sealing Column Caps
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Pier Cap Sealing Complete
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Wind Driven Rain Under Segments
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Improved Inspection and Maintenance Access
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Rappelling Tower
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Bore scope Inspection of Stay Saddles
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Check for corrosion and coating condition 40
Suspended Scaffolding
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Inspection of Stay Cables using High Lift
42
Inspection of Stay Cables using High Lift
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Inspection of Stay Cables Using High Lift
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New Access Hatches in Median
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Inspection Inside Median Barrier
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Sunshine Skyway Health Monitoring • Integrated methods of
monitoring bridge condition properties
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Outline • Need for Monitoring
• Existing Monitoring System
• Structural Health Monitoring Goals
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Structural Health Monitoring (SHM)
• Why Monitor the Skyway?
– Vital to regional and multimodal transportation
– Help ensure 100 year design life is met
– Detect problems between visual inspections
– Post hurricane or impact evaluation
– Provide live weather conditions for Traffic Management
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Current Monitoring System
• Global Positioning System (GPS) Receivers
• Automatic Total Stations
• Weather Stations
• Analytical Model
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GPS System
GPS Sensors:
– Leica GPRX 1200+RS500 Receivers
– Post-processed accuracy of 1 centimeter in x and y planes
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GPS Receiver Locations
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Automatic Total Stations
• Leica TCA2003 ATS on Dolphin 101
• Leica TM30 on Dolphin 104
• Accuracy to 1 millimeter
• Redundancy for GPS
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ATS Prism on Tower
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ATS Lines of Sight
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Weather Station
• Weather Sensors
– Wind Speed/Direction
– Temperature/Humidity
– Barometric Pressure
– Internet-connected with live web-cams
– Rain Gauge
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Weather Station Website
• Tabular and graphical data available
• Website updated every 15 minutes
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Structural Health Monitoring (SHM) Goals:
• Design verification (with analytical model)
• Establish normal movement
• Extreme event monitoring
• Deterioration/settlement detection
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Design Verification – Theoretical estimation of time-dependent stay
forces to compare with empirical test results
– Calibration/verification of GPS/ATS readings
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Analytical Model
• Time-dependent frame analysis model
• MIDAS Civil software used
• Main model P6S (106) to P6N (117)
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Wind Analysis Graphical Results
1.37 ft
1.01 ft
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Normal Operating Parameters
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Extreme Event Monitoring • Hurricane effects
• Ship Impact
• Wind/rain cable vibration
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Future Goals
• Fully calibrated analytical model
• Establish thresholds of movement
• Additional permanent sensors
– Strain measurements
– Stay vibration measurements
– Thermal measurements
• Automated alerts
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Strategy for a 100 year Bridge Life:
• Continue a “Preventive” focused inspection and maintenance program
• Continue the "Skyway Preservation Committee” to sustain the vision for a 100 year life for the bridge
• Give special attention to long term Corrosion Prevention
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Questions?
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Thank you for participating
Florida Department of Transportation District Structures Maintenance Office
Tampa, Florida
67 April 24, 2014
NATIONAL BRIDGE PRESERVATION PARTNERSHIP CONFERENCE
Special Considerations for Maintenance of the Sunshine Skyway Bridge
