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Design for Service Life,Design for Service Life, Bridge Birth Certificate & Bridge Birth Certificate &

Concrete Structures Concrete Structures Management ConceptsManagement Concepts

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

HILLHILL

AASHTO Bridge SubAASHTO Bridge Sub--Committee MeetingCommittee MeetingTT--9 9 ––

Technical Committee for Bridge Technical Committee for Bridge PreservationPreservationJuly 6, 2009July 6, 2009

New Orleans, LANew Orleans, LA

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Discussion TopicsDiscussion TopicsService Life DesignService Life Design––

Work Being Done in EuropeWork Being Done in Europe

––

Current US PracticeCurrent US Practice––

Exposure ConditionsExposure Conditions

––

Deterioration Mechanisms / Protection SystemsDeterioration Mechanisms / Protection Systems––

Mathematical ModelingMathematical Modeling

––

Limit States / Design ProcessLimit States / Design ProcessBridge Birth CertificateBridge Birth Certificate––

PurposePurpose

––

Documentation Examples & TemplatesDocumentation Examples & Templates––

Integration with Inventory Management Integration with Inventory Management SystemsSystems

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ffééddéérationration internationaleinternationale du du bbéétonton(The International Federation for (The International Federation for Structural Concrete)Structural Concrete)Writing new Model Code to include Writing new Model Code to include Service Life DesignService Life DesignPublication of 1Publication of 1stst draft scheduled for draft scheduled for The Third International The Third International fibfib CongressCongress–– Washington, DCWashington, DC–– May 29 to June 3, 2010May 29 to June 3, 2010

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

Some key areas of interest–– Probabilistic performance based service Probabilistic performance based service

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

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

deterioration mechanisms.deterioration mechanisms.

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What do these Bridges have in What do these Bridges have in common?common?

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AnswerAnswer

Although not similar in: Although not similar in: –– Structure TypeStructure Type–– MaterialsMaterials–– AgeAge–– Geographic LocationsGeographic Locations

They are all:They are all:–– Deteriorating with timeDeteriorating with time

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Service Life (Durability) DesignService Life (Durability) Designfibfib Bulletin 34 Bulletin 34 –– Model Code for Service Model Code for Service Life Design (2006)Life Design (2006)Establishes design proceduresEstablishes design procedures––

to Resist Deteriorationto Resist Deterioration

––

from Environmental Actionsfrom Environmental Actions

In 4 Levels of DesignIn 4 Levels of Design––

Full ProbabilisticFull Probabilistic

––

Partial FactorPartial Factor––

““Deemed to SatisfyDeemed to Satisfy””

––

Avoidance of DeteriorationAvoidance of Deterioration

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AASHTO LRFD Service Life AASHTO LRFD Service Life (Durability) Design Requirements(Durability) Design Requirements2.5.2.1.1 2.5.2.1.1 –– The contract documents The contract documents shall call for quality materials and for shall call for quality materials and for the application of high standards of the application of high standards of fabrication and erection.fabrication and erection.

Structural steel shall be self Structural steel shall be self protecting or have longprotecting or have long--life coating life coating systems or systems or cathodiccathodic

protection.protection.

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AASHTO LRFD Service Life AASHTO LRFD Service Life Design RequirementsDesign Requirements

C2.5.2.1.1 C2.5.2.1.1 –– The intent of this Article The intent of this Article is to recognize the significance of is to recognize the significance of corrosion and deterioration of corrosion and deterioration of structural materials to the longstructural materials to the long--term term performance of a bridge.performance of a bridge.Durability also mentioned in C5.4.2.1 Durability also mentioned in C5.4.2.1 and 5.12.1.and 5.12.1.

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AASHTO LRFD Service Life AASHTO LRFD Service Life Design RequirementsDesign Requirements

Expectations for durability existExpectations for durability existAll recommendations qualify as All recommendations qualify as ““deemed to satisfydeemed to satisfy”” requirementsrequirementsCode gives no guidance on how long Code gives no guidance on how long a structure should remain in servicea structure should remain in serviceLacks models for prediction of Lacks models for prediction of deterioration of structuresdeterioration of structuresNo metrics to define if a durable No metrics to define if a durable design is achieveddesign is achieved

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Service Life Design BasicsService Life Design Basics

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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Life ExpectancyLife Expectancy

AASHTO LRFD Bridge Design AASHTO LRFD Bridge Design Specifications Specifications –– Section 1.2Section 1.2

–– Design Life Design Life ––

Period of time on which Period of time on which the statistical derivation of transient the statistical derivation of transient loads is based loads is based ––

75 years for these 75 years for these

Specifications.Specifications.

–– Service Life Service Life ––

The period of time that The period of time that the bridge is expected to be in the bridge is expected to be in operation.operation.

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WhatWhat’’s a Reasonable Service Life?s a Reasonable Service Life?

50, 75, 100, 150 years, 50, 75, 100, 150 years, …… more?more?

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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Indicative Values forIndicative Values for Design Service Life Design Service Life –– fibfib Bulletin 34Bulletin 34

Design Service Design Service Life, yrsLife, yrs

ExamplesExamples

1010 Temporary Structures Temporary Structures (Structures or parts of structures that can be dismantled with a(Structures or parts of structures that can be dismantled with a

view to being review to being re--used are not to be considered temporary)used are not to be considered temporary)

1010--2525 Replaceable structure parts, e.g., Replaceable structure parts, e.g., gantry girders, bearingsgantry girders, bearings

1515--3030 Agricultural and similar structuresAgricultural and similar structures

5050 Buildings and other common Buildings and other common structuresstructures

100100 Monumental buildings, bridges, and Monumental buildings, bridges, and other civil engineering structuresother civil engineering structures

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Service Life Designed Structures Service Life Designed Structures

Great Belt Bridge, Denmark (100 Great Belt Bridge, Denmark (100 yrs)yrs)

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Confederation Bridge, Canada (100 Confederation Bridge, Canada (100 yrs)yrs)

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San Francisco San Francisco –– Oakland Bay Bridge Oakland Bay Bridge (150 yrs)(150 yrs)

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What About These Structures? What About These Structures?

Representing the majority of the Representing the majority of the 600,000+ Bridges in the US600,000+ Bridges in the US

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Exposure ConditionsExposure Conditions

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Site Exposure ConditionsSite Exposure Conditions

AggressivityAggressivity of Environmentof Environment–– Sea waterSea water–– DeDe--icing agentsicing agents–– Chemical attackChemical attack

Temperature / HumidityTemperature / Humidity–– Freeze / thaw cyclesFreeze / thaw cycles–– Wet / Dry cyclesWet / Dry cycles–– Tropical (every +10Tropical (every +10ºº

C doubles rate of C doubles rate of

corrosion)corrosion)

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Member Exposure ConditionsMember Exposure Conditions

MarineMarine–– Submerged, tidal, splash, atmospheric Submerged, tidal, splash, atmospheric

zoneszones

Geographic OrientationGeographic Orientation–– NN--SS--EE--W, seaward, landwardW, seaward, landward

Surface OrientationSurface Orientation–– PondingPonding, condensation, protection from , condensation, protection from

wetting, cornerswetting, corners

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Exposure Classes Exposure Classes –– European Standard ENEuropean Standard EN--206206--11

ClassClass DescriptionDescription

X0X0 No Risk of Corrosion or AttackNo Risk of Corrosion or Attack

XC1XC1--XC4XC4 Corrosion Induced by CarbonationCorrosion Induced by Carbonation

XD1XD1--XD3XD3 Corrosion induced by chlorides other Corrosion induced by chlorides other than from sea water than from sea water

XS1XS1--XS3XS3 Corrosion induced by chlorides from Corrosion induced by chlorides from sea watersea water

XF1XF1--XF4XF4 Freeze/thaw attack with or without deFreeze/thaw attack with or without de-- icing agentsicing agents

XA1XA1--XA3XA3 Chemical attackChemical attack

2323

DeteriorationDeterioration

Nothing lasts foreverNothing lasts forever

Every material deteriorates at a Every material deteriorates at a unique rateunique rate

Deterioration rate is dependent on Deterioration rate is dependent on exposure conditionsexposure conditions

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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)

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Deterioration MechanismsDeterioration MechanismsStructural SteelStructural Steel–– Corrosion after Breakdown of Protective Corrosion after Breakdown of Protective

Coating SystemsCoating Systems

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Protection SystemsProtection Systems

MaterialMaterial’’s Own Ability to Resist s Own Ability to Resist Deterioration Deterioration –– Concrete Quality Concrete Quality (Permeability) and Cover(Permeability) and Cover

Protective CoatingsProtective Coatings

Membranes & OverlaysMembranes & Overlays

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Deterioration ModelsDeterioration Models

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Chloride Induced Corrosion ModelsChloride Induced Corrosion Models

FickFick’’ss 22ndnd Law Models Time to Law Models Time to InitiateInitiate Corrosion in Corrosion in UncrackedUncracked ConcreteConcrete

Ccrit C x cov t,( ) Co Cs Δx, Co−( ) 1 erfcov Δx−

2 Dapp C, t⋅⋅

⎛⎜⎝

⎞⎟⎠

−⎛⎜⎝

⎞⎟⎠

⋅+

C(x,tC(x,t)) Chloride concentration at depth & timeChloride concentration at depth & time

erferf Mathematical error functionMathematical error function

CC

critcrit Critical chloride content (to initiate corrosion)Critical chloride content (to initiate corrosion)

CC

oo Initial chloride content of the concreteInitial chloride content of the concrete

CC

s,s,ΔΔxx Chloride concentration at surface or depth Chloride concentration at surface or depth ΔΔxx

covcov Depth of concrete coverDepth of concrete cover

DD

app,Capp,C Apparent coefficient of chloride diffusion in Apparent coefficient of chloride diffusion in

concrete (permeability)concrete (permeability)

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Deterioration Models / Limit StatesDeterioration Models / Limit States

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Limit States Limit States –– Reinforced ConcreteReinforced Concrete

1 1 -- DepassivationDepassivation –– No damage to No damage to reinforcing / end of initiation phase, reinforcing / end of initiation phase, corrosion beginscorrosion begins2 2 -- Cracking Cracking –– Initial expansion of Initial expansion of corrosion bycorrosion by--productsproducts3 3 -- SpallingSpalling –– Corrosion byCorrosion by--products cause products cause loss of concrete cover and bond to loss of concrete cover and bond to reinforcing steelreinforcing steel4 4 -- Collapse Collapse –– Loss of reinforcing steel Loss of reinforcing steel cross section from corrosioncross section from corrosion

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Limit StatesLimit States

Current practice for new structures is Current practice for new structures is DepassivationDepassivation phasephasefibfib Commission 5 established task Commission 5 established task groups on June 18groups on June 18--19, 2009 in 19, 2009 in LondonLondon to better define:to better define:–– Critical Chloride Content to cause Critical Chloride Content to cause

reinforcing steel reinforcing steel depassivationdepassivation–– Measurable limits for cracking, Measurable limits for cracking, spallingspalling, ,

and loss of sectionand loss of section

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Structural vs. Durability Issues Structural vs. Durability Issues DesignDesign

Design Work ItemDesign Work Item Structural IssuesStructural Issues Durability IssuesDurability Issues

Identify OwnerIdentify Owner’’s s Requirements & DesiresRequirements & Desires

Functionality, Capacity (# Functionality, Capacity (# lanes), Appearancelanes), Appearance

Target Service LifeTarget Service Life

Identify Externally Applied Identify Externally Applied ActionsActions

Loads (Self weight, Live Loads (Self weight, Live Loads, Wind, Thermal, Loads, Wind, Thermal, Seismic, etc.) and Load Seismic, etc.) and Load FactorsFactors

Environmental actions Environmental actions (chloride attack, carbonation, (chloride attack, carbonation, freezefreeze--thaw, chemical attack, thaw, chemical attack, etc.)etc.)

Select MaterialsSelect Materials Concrete Strength, Steel Yield Concrete Strength, Steel Yield & Ductility and Resistance & Ductility and Resistance FactorsFactors

Chloride diffusion coefficient Chloride diffusion coefficient in concrete, reinforcing steel in concrete, reinforcing steel type & coating (plain, epoxy type & coating (plain, epoxy coated, stainless)coated, stainless)

Determine DimensionsDetermine Dimensions Spans, Component cross Spans, Component cross sectionssections

Cover dimensionsCover dimensions

Summarize ResultsSummarize Results Construction Plans & Construction Plans & Specifications, EngineerSpecifications, Engineer’’s s Cost Estimate, Calculation Cost Estimate, Calculation BooksBooks

Durability Report (initiate Durability Report (initiate Birth Certificate), Birth Certificate), Construction Specifications Construction Specifications (new Diffusion Coefficient (new Diffusion Coefficient testing), Engineertesting), Engineer’’s Cost s Cost EstimateEstimate

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What is Needed to Implement a What is Needed to Implement a Service Life Design Process?Service 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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Birth CertificateBirth Certificate

fibfib New Model Code chapter 2, will New Model Code chapter 2, will define a Birth Certificate.define a Birth Certificate.

A document, report or technical file (depending on the size and complexity of the structure concerned) containing engineering information formally defining the form and the condition of the structure after construction. The document / report should provide specific details on parameters important to the durability and service life of the structure concerned (e.g. cover to reinforcement, concrete permeability, environmental conditions, quality of workmanship achieved etc) and the basis upon which future knowledge of through-life performance should be recorded. This framework should provide a means of comparing actual behaviour / performance with that anticipated at the time of design of the structure. The document / report should facilitate ongoing (through-life) evaluation of the service life which is likely to be achieved by the structure.

3535

Birth Certificate PurposeBirth Certificate Purpose

Contains engineering information Contains engineering information defining form and condition of defining form and condition of structure at end of constructionstructure at end of construction

Documents specific parameters Documents specific parameters affecting durability of structureaffecting durability of structure

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Structural vs. Durability Issues Structural vs. Durability Issues ConstructionConstruction

Construction Work ItemConstruction Work Item Structural IssuesStructural Issues Durability IssuesDurability Issues

Perform, Monitor & Inspect Perform, Monitor & Inspect WorkWork

Verify dimensions, test & Verify dimensions, test & document material strength document material strength propertiesproperties

Verify and map cover, test & Verify and map cover, test & document actual material document actual material durability properties (chloride durability properties (chloride diffusion coefficient, etc.)diffusion coefficient, etc.)

Track VariancesTrack Variances Accept / Accept with cost Accept / Accept with cost adjustment for deficiencies / adjustment for deficiencies / RejectReject

Accept / Accept with cost Accept / Accept with cost adjustment for deficiencies / adjustment for deficiencies / RejectReject

Summarize ResultsSummarize Results AsAs--Built Plans, Load RatingBuilt Plans, Load Rating Durability Rating, update Durability Rating, update Birth CertificateBirth Certificate

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Birth Certificate Purpose Birth Certificate Purpose (continued)(continued)

Compares actual behavior / Compares actual behavior / performance with that anticipated performance with that anticipated during designduring design

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

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Structural vs. Durability IssuesStructural vs. Durability Issues InIn--Service UseService Use

Work ItemWork Item Structural IssuesStructural Issues Durability IssuesDurability Issues

Routine Visual Inspections Routine Visual Inspections (Biennial (Biennial ––

required by law)required by law)To detect obvious defects To detect obvious defects with minimal testingwith minimal testing

Same as structuralSame as structural

InIn--Depth Monitoring (every 7Depth Monitoring (every 7--

10 years)10 years)

Reactive Reactive ––

Identify problem Identify problem areas as they occur (Concrete areas as they occur (Concrete Cracks & Spalls, Reinforcing Cracks & Spalls, Reinforcing Corrosion, Joint and Bearing Corrosion, Joint and Bearing failure)failure)

Proactive Proactive ––

Testing to monitor Testing to monitor inin--service conditions (chloride service conditions (chloride diffusion coefficient, chloride diffusion coefficient, chloride profiles, chloride surface profiles, chloride surface concentration)concentration)

AssessmentAssessment Change in Use/Loading or Change in Use/Loading or After Significant Event After Significant Event (Earthquake, Hurricane, (Earthquake, Hurricane, Flood, Fire, Explosion, Flood, Fire, Explosion, Truck/Ship Impact)Truck/Ship Impact)

Assess Remaining Service Life Assess Remaining Service Life of Componentsof Components

Rehabilitation/InterventionRehabilitation/Intervention Replace/Repair/Strengthen Replace/Repair/Strengthen damaged structural damaged structural componentscomponents

Perform Corrosion Surveys Perform Corrosion Surveys --

Add Corrosion Protection Add Corrosion Protection Systems (Galvanic, Systems (Galvanic, CathodicCathodic

Protection, or Electrochemical Protection, or Electrochemical Systems)Systems)

DismantlingDismantling Demolish & Remove WasteDemolish & Remove Waste Recycle & ReRecycle & Re--Use MaterialsUse Materials

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Birth Certificate Birth Certificate –– Table of ContentsTable of Contents

1) Identification of Asset 1) Identification of Asset –– Description & Identification of StructureDescription & Identification of Structure–– General Plan & Typical Section DrawingsGeneral Plan & Typical Section Drawings–– Design Parameters / Target Service LifeDesign Parameters / Target Service Life

2) Environmental Exposure 2) Environmental Exposure ConditionsConditions

3) Deterioration Models3) Deterioration Models

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Birth Certificate Birth Certificate –– Table of Contents (continued)Table of Contents (continued)

4) Summary of Individual Structure 4) Summary of Individual Structure ComponentsComponents–– Mapping of:Mapping of:

Exposure Classes/SeveritiesExposure Classes/SeveritiesDeterioration ModelsDeterioration ModelsMean Material PropertiesMean Material PropertiesMean Cover DimensionsMean Cover DimensionsExpected Service Life (Target & Remaining)Expected Service Life (Target & Remaining)

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5) Summary of Ancillary 5) Summary of Ancillary (Replaceable) Components(Replaceable) Components–– Mapping & Documentation (similar to Mapping & Documentation (similar to

Structural Components) for:Structural Components) for:BearingsBearingsExpansion JointsExpansion JointsProtective Membrane SystemsProtective Membrane Systems

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6) In6) In--Service InspectionService Inspection–– Routine & Special Maintenance ScheduleRoutine & Special Maintenance Schedule–– Schedule of InspectionsSchedule of Inspections

Routine Visual (Biennial)Routine Visual (Biennial)InIn--Depth Monitoring and Sampling (7Depth Monitoring and Sampling (7--10 10 years)years)

–– Special Test Method RequirementsSpecial Test Method Requirements

7) Dismantling Plan7) Dismantling Plan

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Example Birth CertificateExample Birth Certificate

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Birth Certificate Birth Certificate –– Next StepsNext Steps

Determine Guidelines for:Determine Guidelines for:–– Type and number of tests of material Type and number of tests of material

durability propertiesdurability properties–– Type and extents of as constructed Type and extents of as constructed

concrete cover measurementsconcrete cover measurements

Develop templates for additional Develop templates for additional Deterioration Models for the Example Deterioration Models for the Example Birth Certificate (Carbonation)Birth Certificate (Carbonation)

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Birth Certificate Birth Certificate –– Next StepsNext Steps

Develop criteria for deterioration Develop criteria for deterioration models for Ancillary Components models for Ancillary Components (Joints & Bearings)(Joints & Bearings)Develop a suggested format for Develop a suggested format for Inspection & Maintenance Schedule Inspection & Maintenance Schedule (similar to automobile maintenance (similar to automobile maintenance schedules)schedules)Develop a template for a Dismantling Develop a template for a Dismantling PlanPlan

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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

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Questions?Questions?

Thank youThank you