federal highway administration long term bridge ...sp.bridges.transportation.org/documents/2011...
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Federal Highway Administration Long‐Term Bridge Performance Program
LTBP UpdateforAASHTO Subcommittee on Bridge & Structures 2011
Scientific Quality Bridge Performance
Database
• Detailed inspection, periodic evaluation and monitoring (representative sample of bridges)
• Taking advantage of legacy data and existing research activities
Desired/Anticipated Outcomes
Improved knowledge of bridge performance
Development of improved predictive and deterioration models
Means to quantify effectiveness of various maintenance, preservation, repair and rehabilitation strategies
Tools for bridge management
Standards for testing and monitoring
LTBP Objective
Program Highlights to Date
• Identification of key performance issues• Pilot bridge program• Inspection protocols• Data infrastructure & interface - LTBP Bridge Portal • Development of long term data collection phase• Outreach, communication & collaboration
Most Common Bridges in the US
Material / Type Number Cumulative
Area
Million Sq. m.
Cumulative
ADT
Millions VPDSimple Span Steel Stringer 103,836 469 704Continuous Steel Stringer 46,491 720 618Simple Span Concrete Slab 33,873 78 114Simple Span Concrete Stinger 9,988 51 44Simple Span Concrete T Beam 21,162 87 121Continuous Concrete Slab 31,565 132 190Continuous Concrete T Beam 6,247 53 102Simple Span Prestressed Concrete
Stringer
51,731 637 655
Simple Span Prestressed Concrete
Multiple Box Beam
38,103 122 181
Continuous Prestressed Concrete
Stringer
13,560 205 146
Totals 356,556 2,554 2,875
Pilot Bridges
• I-15 over Cannery Road near Perry, UT
• Constructed in 1976• Single span AASHTO beams with
integral abutment• CIP concrete deck with asphalt
overlay and membrane• AADT of 22,250 with 29% truck traffic
• U.S Route 15 over I-66• Constructed in 1979• Continuous built-up steel
girder• CIP concrete deck• AADT of 16,500 with 6%
truck traffic
VA UT
Pilot Study PhasePilot Study Phase
Activity VA UT CA NJ NY MN FL
Bridge Selection Done Done Done Done Done Done Done
Finite Element Model Done Done Done Done Done Done Done
NDE Deck Survey Done Done Done Done Done Done Done
Visual Inspection Done Done Done Done Done Done Deck, Super. Done
Coring & Physical Testing Done Done Done Done Done Done Deck, Super. Done
Live Load Testing Done Done Done Done Done Done Done
Analysis of Results In Progress In Progress In
ProgressIn Progress
In Progress
In Progress In Progress
VA : Continuous steel stringerUT : Simple span pre-stressed concrete stringerCA : 2-span prestressed post-tensioned continuous CIP box girderNJ : Simple span steel stringerNY : Two simple spans of adjacent concrete box beamsMN : Steel deck trussFL: Precast, segmental post-tensioned concrete box beams
Pilot Study Phase Pilot Study Phase ––
Valuable Lessons LearnedValuable Lessons Learned
1. Coordination of activities with DOT2. Speed at which the desired amount & quality of data can be
collected, 3. Duration of traffic interruptions, 4. Ancillary costs – traffic control onsite power, etc.5. Data interpretation and integration & correlation of data from different
tests6. Coordination of field activities for deploying NDE technologies, and7. Costs of collecting data from a large number of bridges8. Protocols for technology verification and validation
Data Collection ParametersData Collection Parameters
• Maximum automation of data collection
• Speed • Scope and duration
of traffic interruption• Reasonable cost• Repeatability• Reliability
Electrical Resistivity
GPRImpact Echo
USW
Coring
LTBP Inspection & Testing Protocols
Data Infrastructure
LTBP Portal
• LTBP Portal is a web-based application• Security features (authentication, authorization)• Portal home page: data querying, data and image uploads, account
management• Provides a flexible and convenient filtering mechanism• Complex cross-data source querying (NBI, Pontis, Clarus and
Wunderground weather data, traffic and accident data, LTBP metadata, image and image metadata, LTBP experiment data)
• Multiple visualization options (table, map, histograms, etc)• Table: paged results, supports paging, sorting, and exporting large
data sets to Excel• Map: overlays bridge conditions and yearly traffic volume
GIS visualization of searched bridges
Size of circles encodes ADT
Color encodes deck condition of 2007
Blue squares indicate WIM stations
GIS visualization of searched bridges
Size of circles encodes ADT
Color encodes deck condition of 2007
Blue squares indicate WIM stations
Performance distribution of this cluster
Each bar indicates the number of bridges with a certain deck condition
The blue bar indicates the subgroup which contains Bridge I-15
Performance distribution of this cluster
Each bar indicates the number of bridges with a certain deck condition
The blue bar indicates the subgroup which contains Bridge I-15
Map shows the location of those 3 bridges that have deck condition 9
Map shows the location of those 3 bridges that have deck condition 9
What is the expected condition in 5 years?
The substructure condition is predicted to decrease to 7 whereas to deck condition is most likely to stay at 7
What is the expected condition in 5 years?
The substructure condition is predicted to decrease to 7 whereas to deck condition is most likely to stay at 7
How fast did the deterioration process compared to similar bridges?
How fast did the deterioration process compared to similar bridges?
Bridge Portal Rollout
Long Term Data Collection PhaseLong Term Data Collection Phase
• Begin 2012• Reference Bridges • Cluster Bridges• Scale & Scope of activities will depend heavily on future
resources
Reference Bridge – Data Collection
Visual InspectionNon‐standardArms lengthSegmentalConventional Tools
Mat’l TestingMaterial SamplingStiffnessStrengthPorosity
Chloride Content
Global TestingLoad Testing Modal TestingContinuous
Monitoring
NDEImpact EchoGPRUltrasonicSeismicResistivity
Approximat e Scale: 200 ft
Reference Bridge and Supporting Cluster
Visual Visual InspectionInspectionNon‐standardArms lengthSegmentalConventional Tools
Comparison: Reference vs. ClusterComparison: Reference vs. ClusterIdentify discrepancies –
establish root
causesEstablish typical levels of variability
Reference Bridge Cluster bridges
Approximat e Scale: 30 mi
Multiple Clusters of Similar Bridges
Cluster of Bridge
Type A
Approximate Scale: 3000
mi
Comparison: Cluster vs. ClusterComparison: Cluster vs. ClusterIdentify influences of climate, traffic,
maintenance practices, etc.
Outreach, Communication & CollaborationOutreach, Communication & Collaboration
• TRB Advisory Board• LTBP State Coordinators • T-9• T-18• TSP2 Bridge Preservation Partnerships• TRB committees