service-life engineering examples for new and existing...
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Service-Life Engineering Examples for New and Existing Bridges
Paul G. Tourney, P.E.Neal S. Berke, Ph.D., FACI, FASTM
Tourney Consulting GroupKalamazoo, MI
AASHTO – T9 – Norfolk, VA , May 16, 2011
Key Industry Trends
• Service life requirements and extensions
• Design-build contracts (Not always low bid)
• Design-build-operate contracts
• New technologies in market– Reinforcing systems (coated, alloy, and non-metallic) – Surface treatments– Inhibitors– SCMs and blended systems
• Industry moving from prescriptive to performance- based specifications
AASHTO – T9 – Norfolk, VA , May 16, 2011
Service Life Engineering
• Drives innovation within industry
• Effective to sort through wide range of protection systems (past, present, and future)
• Necessary to implement comprehensive performance- based specifications
• Excellent tool for asset management programs
• Validated modeling tools are available
• Require increased (not decreased) understanding of materials
AASHTO – T9 – Norfolk, VA , May 16, 2011
Time
Det
erio
ratio
n
Cor
rosi
on
ASRCo
mbi
ned
Sulfate AttackDEF
Deterioration Mechanisms
Service Life Simulation
Time
Dam
age
(Cos
t)
Transport of chlorides
Corrosion Initiation
Initial physical damage Repair
event reduces damage
End of Economic Service Life
Stage 1 Stage 2 Stage 3
Initiation Propagation Repair
Economic Limit
Barrier system life
Potential End of Operational Service Life
End of Serviceability
NewConstruction
ChlorideContamination
Period
CorrosionInitiation
CorrosionDamage
TIME
Dam
age
Service Life Performance(Base Case)
Ref. Tuutti
X
AASHTO – T9 – Norfolk, VA , May 16, 2011
End of Serviceability Repairs
NewConstruction
ChlorideContamination
Period
CorrosionInitiation
CorrosionDamage
I
TIME
Dam
age
3
2
Service Life Performance(Repetitive Repair Case)
Ref. Tuutti
X
AASHTO – T9 – Norfolk, VA , May 16, 2011
Repair
NewConstruction
Extended ChlorideContamination
Period
CorrosionInitiation
CorrosionDamage
RepairedCondition
TIME
Dam
age
Ref. Tuutti
End of Serviceability
Service Life Performance(Protection and Repair Case)
X
AASHTO – T9 – Norfolk, VA , May 16, 2011
NewConstruction
Extended ChlorideContamination
Period
CorrosionInitiation
SlowerCorrosionDamage
TIME
Dam
age
Ref. Tuutti
End of Serviceability
Service Life Performance(High Level Protection Case)
AASHTO – T9 – Norfolk, VA , May 16, 2011
New Durability Design Methodology
DesignService Life Objectives
Local ExposuresLocal Materials
DesignService Life Objectives
Local ExposuresLocal Materials
Construction
Assess VariationQA / QC
Construction
Assess VariationQA / QC
BiddingEvaluationSelection
BiddingEvaluationSelection
Value Engineering
ProposalsEvaluationsApprovals
Value Engineering
ProposalsEvaluationsApprovals
Service Life
Modeling
AASHTO – T9 – Norfolk, VA , May 16, 2011
Simplified History of SLM
Gut Feel
ExcelDatasheets
Hand Calculation
s
Empirical Spreadsheet
s•Grace•Virginia Tech•Many Others
DuraModel®Life 365Version 1.0
DuraPGulf
Life 365Version 2.0
ConcreteWork s
4SightNIST
STADIUM®
SIMCO
Fickian Models
Multiple Mechanism Models
AASHTO – T9 – Norfolk, VA , May 16, 2011
Concrete Testing (Durability)Resistance-Based Testing Criteria w/o SLM
• Resistance is not permeability.
• How are wet – dry exposures addressed?
• How are admixtures that modify hydrophobic properties or reduce electrical resistance considered?
• How are innovations supported?? (D-B and D-B-O Contracts)
– New rebar types (12 types of SS, 3 types of ECR, Galvanized, Alloys, etc.)
– New admixtures, new SCMs, new surface technologies
• How are these tests alone supporting “real” performance –based specifications?
AASHTO – T9 – Norfolk, VA , May 16, 2011
Concrete Testing (Durability)Diffusion-Based Testing Criteria for SLM
• Resistance tests do not determine permeability.
• ASTM C1556 Bulk Diffusion– Saturated concrete exposures only
– Field determinations questionable at best (possible to determine two or more De for same concrete)
• How are admixtures that modify hydrophobic properties or reduce electrical resistance considered?
AASHTO – T9 – Norfolk, VA , May 16, 2011
Concrete Testing (Durability)Multiple Mechanistic Testing Criteria for SLM
• Porosity determines permeable voids (ASTM C642)
• Ion migration determine multiple ion species diffusion in saturated concrete (Modified ASTM C1202)
• Drying Test (Modified ASTM E96) determine moisture transport.
• Pore solution determination or estimation (per NIST) provides electroneutrality and binding parameters.
• How are admixtures that modify hydrophobic properties or reduce electrical resistance considered?
AASHTO – T9 – Norfolk, VA , May 16, 2011
Transport Testing:• Porosity
• Ion Migration
• Moisture Transport
• Pore Solution Chemistry
AASHTO – T9 – Norfolk, VA , May 16, 2011
Modified ASTM Test Methods
ASTM E96M
ASTM C1202
Concrete MaterialsCement / SCM Chemistry
AggregatesAdmixtures
Concrete MaterialsCement / SCM Chemistry
AggregatesAdmixtures
Reinforcing SystemBlack Steel
CoatedGalvanized
Alloys
Reinforcing SystemBlack Steel
CoatedGalvanized
Alloys
Transport PropertiesMoisture
Ion DiffusivityBinding
ASR SusceptibilityF/T Resistance
Transport PropertiesMoisture
Ion DiffusivityBinding
ASR SusceptibilityF/T ResistanceElement Geometry
Concrete CoverCorners and Joints
Element GeometryConcrete Cover
Corners and Joints
Surface TreatmentsSealers and Coatings
Overlays
Surface TreatmentsSealers and Coatings
Overlays
Exposure ConditionsCl-, SO4 , Alkali Loading
MoistureTemperatures
Exposure ConditionsCl-, SO4 , Alkali Loading
MoistureTemperatures
Corrosion Initiation Modeling
Corrosion InitiationModeling
STADIUM®STADIUM®
Life 365Life 365
OtherOther
Engineering Assessment
• Propagation• Damage Index• Iterations• Life Cycle
Cost Analysis• Recommend
Service Life Engineering Process
Sakonnet River Bridge, RIDOT
75 Year Service Life Requirement:• Localized Stainless Steel• Localized Galvanized Steel• Localized Corrosion Inhibitor
AASHTO – T9 – Norfolk, VA , May 16, 2011
East End Bridge, KYDOT
100 Year Service Life Requirement:• Localized Stainless Steel• High Performance Membrane• Micro Composite Alloy
AASHTO – T9 – Norfolk, VA , May 16, 2011
Ford Island Bridge, Pearl Harbor, HI
Construction Variance Problems • Initiated Performance Specification• Require Service Life Modeling
U.S. Navy Marine Concrete Specification
UFGS-03 31 29
Pier 5 – Portsmouth, VA
Engineer: Moffatt NicholContractor: SkanskaPrecast Concrete: Bayshore Precast ProductsRM Concrete: Commercial Ready Mix Products
University of Kentucky
U.S. Navy Modular Hybrid Pier (MHP)
P-B Specifications and SLE
U. S. Department of State Embassy Projects
Abu DhabiDubaiRowandaAstana, KazDjibouitEcuadorSenegal
Cleveland Clinic – Abu Dhabi
Service Life Engineering (Existing Structures)
• Requires a quality condition assessment– Detailed exposure profiles
• Moisture
• Contamination
– Understanding of in-place concrete properties• Transport properties (including resistivity)
– Corrosion survey
• Review of potential options for repair
• Conduct service life modeling
• Life-Cycle Analysis and Recommendations
AASHTO – T9 – Norfolk, VA , May 16, 2011
71 Bridges, City of St. Louis
Asset Management Program
Sometimes it is obvious there is no modeling needed.
Engineering towards replacement or cathodic protection is required.
Validation Testing of Protection Options
Cathodic Protection System Options
Galvanic Anode
Impressed Current
Spray Arc Metalizing
Summary• Service life requirements is a growing trend.
• Design-Build contracts need service life engineering.
• Service life engineering can be the basis of innovation, performance-based specifications, and asset management programs.
• Material science understanding will be required. No simple solutions to complex situations.
• Service life modeling techniques exist with a varying level of detail and complexity.
• New construction and maintenance of existing structures are using this engineering process.
AASHTO – T9 – Norfolk, VA , May 16, 2011
3401 Midlink DriveKalamazoo, MI 49048
(269)384-9980www.tourneyconsulting.com
Paul Tourney ([email protected])Dr. Neal Berke ([email protected])