11

Proactive ThroughProactive Through--Life Life Management of BridgesManagement of Bridges

Presented by: Mike Bartholomew, PEPresented by: Mike Bartholomew, PECH2MCH2M HILLHILL

AASHTO SubAASHTO Sub--Committee on Bridges & Structures MeetingCommittee on Bridges & Structures MeetingTT--9 9 –– Technical Committee for Bridge PreservationTechnical Committee for Bridge Preservation

TT--18 18 –– Technical Committee for Bridge Management, Technical Committee for Bridge Management, Evaluation & RehabilitationEvaluation & Rehabilitation

May 24May 24--27, 201027, 2010Sacramento, CASacramento, CA

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Discussion TopicsDiscussion TopicsCurrent US Bridge Management PracticeCurrent US Bridge Management PracticeProactive ThroughProactive Through--Life ManagementLife Management–– Service Life DesignService Life Design–– ConstructionConstruction–– InIn--Service Maintenance & InspectionService Maintenance & Inspection–– Rehabilitation & PreservationRehabilitation & Preservation–– Dismantling PlanDismantling PlanBridge Inventory Management ToolsBridge Inventory Management Tools–– Birth CertificateBirth Certificate–– Life RatingLife RatingPlanning, Funding & SustainabilityPlanning, Funding & Sustainability

33

Why Am I Interested in Bridge Why Am I Interested in Bridge Management?Management?

Unable to Adequately Respond to:Unable to Adequately Respond to:–– WeWe’’re designing bridges to last 75 re designing bridges to last 75

years, arenyears, aren’’t we?t we?–– Design bridge for 100 year life span.Design bridge for 100 year life span.–– Explain how you will achieve the design Explain how you will achieve the design

service life of the structure.service life of the structure.–– We just need to get 5We just need to get 5--10 more years of 10 more years of

use. Design the repair for that.use. Design the repair for that.

Pass What IPass What I’’ve Learned on to Othersve Learned on to Others

44

ffééddéérationration internationaleinternationale du du bbéétonton (The (The International Federation for Structural International Federation for Structural Concrete)Concrete)–– Writing new Model Code to include Service Life Writing new Model Code to include Service Life

DesignDesign–– Publication of 1Publication of 1stst draft scheduled for:draft scheduled for:

The Third International The Third International fibfib Congress & PCI Congress & PCI ConventionConvention–– Washington, DCWashington, DC–– May 29 to June 3, 2010May 29 to June 3, 2010

55

fibfib Commission 5: Commission 5: Structural Service Life AspectsStructural Service Life Aspects

Some key objectives of CommissionSome key objectives of Commission–– Probabilistic performance based service Probabilistic performance based service

life design.life design.–– Inspection, assessment and Inspection, assessment and

performance monitoring.performance monitoring.–– Development and validation of Development and validation of

deterioration mechanisms.deterioration mechanisms.

Task Group 5.10: ThroughTask Group 5.10: Through--Life Life ManagementManagement

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ThroughThrough--Life ManagementLife Management

Integrating All Stages in the Life of a Integrating All Stages in the Life of a StructureStructure–– DesignDesign–– ConstructionConstruction–– InIn--Service Maintenance & InspectionService Maintenance & Inspection–– Intervention (Repair & Rehabilitation)Intervention (Repair & Rehabilitation)–– DismantlingDismantling

Future Oriented toward Sustainable, Future Oriented toward Sustainable, Life Cycle ThinkingLife Cycle Thinking

77

Current US Bridge Management Current US Bridge Management –– Reactive StrategyReactive Strategy

Routine Inspections rely primarily on Routine Inspections rely primarily on Visual ObservationsVisual ObservationsNo deterioration observedNo deterioration observed

No actions takenNo actions taken

Observed deteriorationObserved deteriorationInIn--depth inspectiondepth inspectionAssessment to determine repair typeAssessment to determine repair typeRepairs based on available fundsRepairs based on available funds

88

Disadvantages of Reactive Disadvantages of Reactive StrategyStrategy

When deterioration is observed on When deterioration is observed on surface, the degree of damage is well surface, the degree of damage is well advancedadvanced

Possibility for intervention with Possibility for intervention with preventative maintenance has preventative maintenance has passedpassed

Repairs are extensive and expensiveRepairs are extensive and expensive

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Disadvantages of Reactive Disadvantages of Reactive StrategyStrategy

Funding not readily available for Funding not readily available for unplanned repairs, resulting inunplanned repairs, resulting in……

Delays in performing the needed repairs, Delays in performing the needed repairs, which increaseswhich increases……–– CostCost–– Negative Public PerceptionNegative Public Perception

Prompts questions without good answersPrompts questions without good answers

1010

A reflection upon problems and A reflection upon problems and their solutionstheir solutions

““We canWe can’’t solve problems by using the t solve problems by using the same type of thinking we used when we same type of thinking we used when we created them!created them!””

Albert EinsteinAlbert Einstein

1111

Proactive Bridge ManagementProactive Bridge ManagementBased on knowledge of how materials Based on knowledge of how materials deteriorate with timedeteriorate with time

Monitoring performance against predicted Monitoring performance against predicted behaviorbehavior–– through testing sufficiently in advance of through testing sufficiently in advance of

initiation of visual damageinitiation of visual damage

Part of overall concept of ThroughPart of overall concept of Through--Life Life Management of StructuresManagement of Structures

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Service Life Design PrinciplesService Life Design Principles

DeteriorationDeterioration–– Materials deteriorate at a unique rate, Materials deteriorate at a unique rate,

depending on exposure conditionsdepending on exposure conditions

Durability ResistanceDurability Resistance–– Function of quality of concrete cover Function of quality of concrete cover –– Cover depth over reinforcementCover depth over reinforcement

1313

Deterioration ModelsDeterioration Models

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Deterioration Models / Limit StatesDeterioration Models / Limit States

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Service Life Design ProcedureService Life Design Procedure

Establishing Life ExpectancyEstablishing Life ExpectancyIdentifyingIdentifying–– Environmental Exposure ConditionsEnvironmental Exposure Conditions–– Deterioration MechanismsDeterioration Mechanisms–– Material Resistance to DeteriorationMaterial Resistance to Deterioration

Establishing Mathematical Modeling Establishing Mathematical Modeling Parameters to Predict DeteriorationParameters to Predict DeteriorationSetting Acceptable Damage LimitsSetting Acceptable Damage Limits

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Service Life (Durability) DesignService Life (Durability) Design

fibfib Bulletin 34 Bulletin 34 –– Model Code for Model Code for Service Life Design (2006)Service Life Design (2006)

Establishes design Establishes design proceduresprocedures–– to Resist Deteriorationto Resist Deterioration–– from Environmental from Environmental

ActionsActions–– by Mathematical Modelingby Mathematical Modeling

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Establishing Life ExpectancyEstablishing Life Expectancy

50, 75, 100, 150 years50, 75, 100, 150 years……

Expected Service Life is based onExpected Service Life is based on–– OwnerOwner’’s desires and expectationss desires and expectations

Actual Service Life will depend onActual Service Life will depend on–– Exposure conditions of structureExposure conditions of structure–– Quality of materials, design and Quality of materials, design and

constructionconstruction–– Level of maintenance performedLevel of maintenance performed

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Exposure ConditionsExposure Conditions

1919

Deterioration MechanismsDeterioration Mechanisms

Reinforced ConcreteReinforced Concrete–– Chloride Induced Corrosion Chloride Induced Corrosion

(Seawater, de(Seawater, de--icing salts)icing salts)

–– Carbonation Induced Corrosion Carbonation Induced Corrosion (Normal CO(Normal CO22 from atmosphere from atmosphere and RH from 60% to 80%)and RH from 60% to 80%)

2020

Chloride Induced Corrosion ModelsChloride Induced Corrosion Models

FickFick’’ss 22ndnd Law Models Time to Law Models Time to InitiateInitiate Corrosion in Corrosion in UncrackedUncracked Concrete (Cracks < 0.3 mm or 0.012Concrete (Cracks < 0.3 mm or 0.012””))

C(x,t) Chloride concentration at depth & timeChloride concentration at depth & time kg/mkg/m33

x, t Depth from surface / timeDepth from surface / time mm, yrmm, yr

erf Mathematical error functionMathematical error function --

CC critcrit Critical chloride content (to initiate corrosion)Critical chloride content (to initiate corrosion) kg/mkg/m33

Co Initial chloride content of the concreteInitial chloride content of the concrete kg/mkg/m33

Cs Chloride concentration at surfaceChloride concentration at surface kg/mkg/m33

Dapp,C Apparent coefficient of chloride diffusion in Apparent coefficient of chloride diffusion in concreteconcrete

mmmm22/yr/yr

C x t, ( ) Co Cs Co−( ) 1 erfx

2 Dapp c, t⋅⋅⎛⎜⎝

⎞⎟⎠

−⎛⎜⎝

⋅+ Ccrit≤

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New Design ConsiderationsNew Design Considerations

Exposure Classes & ParametersExposure Classes & ParametersSpecifying Material Durability Specifying Material Durability PropertiesProperties–– Concrete Coefficient of Chloride Concrete Coefficient of Chloride

Diffusion (permeability)Diffusion (permeability)–– Reinforcement Critical Chloride ContentReinforcement Critical Chloride Content

Defining Maintenance & Inspection Defining Maintenance & Inspection Schedule & Work ItemsSchedule & Work Items

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Example Service Life Designed Example Service Life Designed Structures Structures

Confederation Bridge, PEI, CanadaConfederation Bridge, PEI, Canada–– 100 yrs 100 yrs –– completed 1997completed 1997

2323

Confederation Bridge DesignConfederation Bridge Design

Exposures 2Exposures 2--4 4 Tidal, Splash & Tidal, Splash & Spray Zones Spray Zones (most critical)(most critical)–– CCss , Chloride , Chloride

Concentration at Concentration at Surface = 17.7 Surface = 17.7 kg/mkg/m33

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Confederation Bridge DesignConfederation Bridge DesignHigh Performance Concrete (HPC)High Performance Concrete (HPC)–– Cement 400 kg/mCement 400 kg/m33

–– Silica fume 50 kg/mSilica fume 50 kg/m33

–– DD app,capp,c , Apparent , Apparent CoeffCoeff. of Chloride Diffusion . of Chloride Diffusion = 4.8x10= 4.8x10--1313 mm22/sec = 15.1mm/sec = 15.1mm22/yr/yr

–– CC oo , Initial Chloride Content = 0 kg/m, Initial Chloride Content = 0 kg/m33

Plain Reinforcing (with electrical Plain Reinforcing (with electrical connectivity for possible future connectivity for possible future cathodiccathodicprotection)protection)–– CC critcrit , Critical Chloride Content , Critical Chloride Content –– 0.4% of 0.4% of

cement (= 1.6 kg/mcement (= 1.6 kg/m33))

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Chloride Content vs. Time Chloride Content vs. Time –– at Various Cover Depthsat Various Cover Depths

20 40 60 80 100Time, yrs

Ccrit2

4

6

50 mm

75 mm

100 mm

Chlo

ride

Conte

nt,

kg/m

3

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Chloride Content vs. Depth Chloride Content vs. Depth –– at Various Structure Agesat Various Structure Ages

20 40 60 80 100Depth, mm

Chlo

ride

Conte

nt,

kg/m

3

5

10

15

Ccrit

Cs

10 yr50 yr

100 yr120 yr

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ConstructionConstruction

Most important stage for achieving Most important stage for achieving the target service life of structurethe target service life of structure

Deviations from intended design Deviations from intended design parameters are inevitableparameters are inevitable

Documentation of actual constructed Documentation of actual constructed material properties and geometry material properties and geometry ––Birth CertificateBirth Certificate

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Construction Monitoring IssuesConstruction Monitoring Issues

Concrete Cover MappingConcrete Cover Mapping–– Cover MetersCover Meters–– PachometersPachometers

Concrete Durability Property TestingConcrete Durability Property Testing

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Concrete Durability TestingConcrete Durability TestingBulk Diffusion Test (ASTM C1556)Bulk Diffusion Test (ASTM C1556)

Rapid Chloride Permeability Test (RCPT) Rapid Chloride Permeability Test (RCPT) --AASHTO T 277 (ASTM C1202)AASHTO T 277 (ASTM C1202)

90 Day Salt 90 Day Salt PondingPonding Method Method --AASHTO T 259 (ASTM C1543) AASHTO T 259 (ASTM C1543)

Rapid Migration Test (RMT) Rapid Migration Test (RMT) --AASHTO TP 64AASHTO TP 64--0303

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InIn--Service PlanningService Planning

Maintenance, Inspection and Maintenance, Inspection and Monitoring Tasks and Schedules Monitoring Tasks and Schedules established during designestablished during design

Tailored specifically to the structureTailored specifically to the structure

Creates awareness for potential Creates awareness for potential damage susceptible detailsdamage susceptible details

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InIn--Service Maintenance PlanService Maintenance Plan

Written Plan defining routine tasksWritten Plan defining routine tasks–– flush drainage pipingflush drainage piping–– remove vegetationremove vegetation–– etc.etc.

Identifies schedule for replaceable or Identifies schedule for replaceable or serviceable itemsserviceable items–– Expansion Joint SealsExpansion Joint Seals–– Coatings & SealersCoatings & Sealers

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InIn--Service Maintenance PlanService Maintenance Plan

Flexible for modifying Activities & Flexible for modifying Activities & Schedule based on observed Schedule based on observed performanceperformance

3333

Inspection & Monitoring PlanInspection & Monitoring Plan

Initial (End of Construction)Initial (End of Construction)–– Birth Certificate documentationBirth Certificate documentation

Routine Inspections (current ~ 2 yrs)Routine Inspections (current ~ 2 yrs)Special Inspections (Scour, FCM)Special Inspections (Scour, FCM)Damage (EQ, Flood, Fire, Collision)Damage (EQ, Flood, Fire, Collision)InIn--Depth Monitoring (~ 10Depth Monitoring (~ 10--20 yr)20 yr)–– Chloride penetration testsChloride penetration tests–– Depth of Carbonation testsDepth of Carbonation tests

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InIn--Depth Monitoring PlanDepth Monitoring PlanChloride penetration testsChloride penetration tests

20 40 60 80 100

Chlo

ride

Conte

nt,

kg/m

3

5

10

15

Ccrit

10 yr50 yr

100 yr120 yr

* - actual (10 yr)

*

*

*

3535

Life RatingLife Rating

Compares actual behavior against Compares actual behavior against performance anticipated in designperformance anticipated in design

Facilitates onFacilitates on--going (throughgoing (through--life) life) evaluation of remaining service lifeevaluation of remaining service life

3636

InterventionIntervention

Scheduled Major RepairsScheduled Major Repairs–– Components not economically feasible Components not economically feasible

to achieve full service lifeto achieve full service lifeDeck OverlayDeck OverlayDeck ReplacementDeck Replacement

–– Implement preImplement pre--planned planned CathodicCathodic Protection systemProtection system

–– Chloride Extraction TechniquesChloride Extraction Techniques

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DismantlingDismantling

Final Step in ThroughFinal Step in Through--Life PlanLife Plan

Structures designed for 75+ yrs Structures designed for 75+ yrs service life will outlive designersservice life will outlive designers

Provide opportunity to capture Provide opportunity to capture designerdesigner’’s knowledges knowledge

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DismantlingDismantling

Demolition Plan should identifyDemolition Plan should identify–– List of Hazardous Materials usedList of Hazardous Materials used–– List of Recyclable Materials usedList of Recyclable Materials used–– Material Disposal StrategiesMaterial Disposal Strategies–– Special Demolition Details required Special Demolition Details required

(Post(Post--tensioning)tensioning)–– Details to Maintain Structural Stability Details to Maintain Structural Stability

((FalseworkFalsework))–– Future Replacement StrategiesFuture Replacement Strategies

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Service Life StagesService Life Stages

4040

Sustainability / Future Planning Sustainability / Future Planning

Sustainability 101Sustainability 101–– Promotes making structure inventory Promotes making structure inventory

last longerlast longer

PlanningPlanning–– Knowledge of when structure will be Knowledge of when structure will be

rehabilitated or taken out of servicerehabilitated or taken out of service–– Allows better scheduling of funding Allows better scheduling of funding

needsneeds

4141

What is Needed to Implement a What is Needed to Implement a ThroughThrough--Life Design Process?Life Design Process?

Further Development ofFurther Development of–– Deterioration Models (especially for Deterioration Models (especially for

Propagation phase)Propagation phase)–– Limit States for Acceptable Damage (including Limit States for Acceptable Damage (including

critical chloride content)critical chloride content)

Creating Design Examples / WorkshopsCreating Design Examples / WorkshopsTransfer Concrete Service Life Design Transfer Concrete Service Life Design Process to Steel and Other MaterialsProcess to Steel and Other MaterialsGet the Attention of FHWA & AASHTO Get the Attention of FHWA & AASHTO State Bridge EngineersState Bridge Engineers

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ThroughThrough--Life ReferencesLife References

fibfib Bulletin 44 Bulletin 44 –– Concrete Concrete structure management: structure management: Guide to ownership and Guide to ownership and good practice (2008)good practice (2008)

Short version published in Short version published in Structural Concrete, Structural Concrete, Volume 10, nos. 2Volume 10, nos. 2--3, 3, (2009)(2009)

4343

ThroughThrough--Life ReferencesLife References

fibfib Bulletin xx Bulletin xx –– Condition Condition control and assessment of control and assessment of reinforced concrete reinforced concrete structures (2010 ?)structures (2010 ?)

fibfib Bulletin 51 Bulletin 51 –– Structural Structural Concrete Textbook on Concrete Textbook on behaviourbehaviour, design and , design and performance (2010)performance (2010)

4444

Concluding RemarksConcluding RemarksService Life Design & Inventory Service Life Design & Inventory ManagementManagement–– Addresses the whole life of the structureAddresses the whole life of the structure–– Requires a new proactive mindset for the Requires a new proactive mindset for the

industryindustry–– Has huge potential for predicting the future Has huge potential for predicting the future

health, safety, and allocation of funding of our health, safety, and allocation of funding of our infrastructureinfrastructure

Process in its InfancyProcess in its Infancy–– Better prediction tools need to be developedBetter prediction tools need to be developed–– But, we need to start somewhereBut, we need to start somewhere

4545

Questions?Questions?

Thank youThank you