S58_Stay Cable Replacement of the Luling Bridge_LTC2013

7/29/2019 S58_Stay Cable Replacement of the Luling Bridge_LTC2013

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Stay Cable Replacementof the Luling Bridge

2013 Louisiana Transportation ConferenceFebruary 20, 2013, Baton Rouge, LA

Armin MehrabiBridge Engineering Solutions

[email protected]


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Hale Boggs (Luling) Bridge


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Statement of Problem

Rusting and water leakage in anchorages

Cracking/splitting of cable cover pipes

Signs of compromise in cables safetyIn 2002, LADOTD initiated a project for

Structural Evaluation of the Stay Cables


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Old Stay CablesParallel Wire System


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Deck and Cross Girder


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Lower

Anchorage


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Upper

Anchorage


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Project TeamInspection through Construction (2002-2012)

LADOTD, Paul Fossier, Project Manager,

Alan Weber, Project Engineer- Construction

CTLGroup, Inspection-Design

BES, Armin Mehrabi, Project manager forInspection-Design, Field Engineer for

Construction Support

TranSystems, Inspection-Repair DesignABMB, Traffic Control Design-Plans

IBT, Design-Construction Support

Kiewit-Louisiana, Construction


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Inspection, Condition Rating, and

Life-Cycle-Cost Analysis


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Assessment of Overall Integrity

Difference between design and measured profile

0.00

200.00

400.00

600.00

800.00

1000.00

1200.00

1400.00

NEI-TE

NEI-TW

NEI-BE

NEI-BW

NEII-T

NEII-B

NEIII-T

NEIII-B

NEIV-TE

NEIV-TW

NEIV-BE

NEIV-BW

NEV-TE

NEV-TW

NEV-BE

NEV-BW

NEVI-T

NEVI-B

Force(Kips)

Measured Force

Design Force

Cable Force Measurement


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Inspection


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Cable Free Length Inspection


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Inspection findings

Damage Severity Levels

Severity Level Status Description

1 Satisfactory Minor deterioration and anomalies noted

2 Poor Deterioration of the protective elements and

potential for degradation. Cables with thislevel of damages need to be routinelymonitored and corrective action needs tobe planned.

3 Critical Deterioration or potential for deterioration ofthe main tension elements (steel wires)

exists. Action (repair) is necessary. Cableswith this level of damages shall be closelymonitored until repairs are applied.


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Severity Level 3 - Critical, Damage Examples


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Summary

40 out of 72 cables were rated critical

All cables had at least damage Level 2

Increasing rate of deterioration was evidentTimely corrective action was needed

Based on a Life-Cycle-Cost Analysis, publicsafety concerns, and importance of thebridge, LADOTD decided to replace all cables


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Cable Replacement Design,and Construction


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Cable Replacement Design

Develop a cost effective design.

Minimize impact on traffic.

Analyze for live load, wind force, and

construction load effects.

Objectives:


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Replacement Cable Design

Selected cable systemParallel Strand System withIndividually Greased Sheathed Seven-wire

Strands Encased in HDPE Cover Pipe


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Replacement cable design

Parallel strand, preferred system

Larger anchorage and cable envelope

Require modifications to existing structure

Increase wind load Change aerodynamic characteristics

Old Cables; 103 to 307, wiresNew Cables; 23,45,57,67, 0.62 strands

Additional 24 reference strand for follow-up

inspections


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Temporary cable design

Need for Temporary cables

Uncertainty in cable condition

Large cable group spacingNeed to maintain traffic w/o load limits


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Temporary Cables

C t ti S


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Construction SequenceInstall Temporary Cables

C t ti S


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Construction SequenceDetension and lower cable


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Construction SequenceDetension and lower cable

C t ti S


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Construction SequenceModification of Anchorage Zones

C t ti S


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Cable Group Old cables New Cables

I 6.3 8.8II 6.3 7.8

III 6.3 7.8

IV 4.3 6.4V 6.3 7.8

VI 7.1 9.8

Cables Outer Diameter in Inches

Constr ction Seq ence


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Construction Sequence


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Construction Sequence


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Construction SequenceWeld PE Pipe


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Construction SequenceHoist PE Pipe


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Construction SequenceHoist PE Pipe


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Construction SequenceInstall Strand and Stress

L E d d A h


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Lower Ends and Anchorages


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Upper Ends and Anchorages


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Modeling and Structural Analysis


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Maintenance of Traffic


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Design for Peripherals

Cable vibration suppression measures

C bl Vib ti S i M


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Cable Vibration Suppression Measures

C bl Vib ti S i M


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Cable Vibration Suppression Measures


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Summary

Inspection performed 2002-2006

Cable replacement design 2007-8

Construction project bid February 2009Construction began September 2009

Zone 1 completed February 2011

All Cables replaced September 2012


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S58_Stay Cable Replacement of the Luling Bridge_LTC2013

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