long lived bridges: recent developments in the united...

TURNER-FAIRBANK HIGHWAY RESEARCH CENTER

Long Lived Bridges:

Recent Developments in the United States

and Future Research Needs

Joseph L. Hartmann, PhD, PE

Leader, Bridge Design and Construction Team

Office of Infrastructure R & D

Federal Highway Administration


Presentation Topics

• Bridge Engineering Issues

• Selected Current FHWA Studies

• Other Research Needs


Bridge Engineering Issues

• Our industry requires structures that are

– Durable

– Constructable

– Maintainable

– Inspectable

– Resilient to extreme events

– Easily adapted to changing demands

– INEXPENSIVE!


Bridge Durability

• Decks

• Higher performance materials

– Corrosion/deterioration resistant

[materials/coatings]

– Crack/fracture resistant

– Fire resistant

– Impact resistant

• Improved design codes (performance-based?)


Bridge Construction

• Fabrication/casting technology

• Construction QA/QC technologies

• Accelerated construction technologies

– Prefab systems and components

– Erection equipment to handle prefab

– Simpler foundations and substructures


Bridge Maintenance and Preservation

• Decks

• Joints

– Superstructure

– Bearings

– Substructure

• Foundations and Approach Slabs

– Scour

– Erosion/settlement


Bridge Inspection and Evaluation

• Simple/hand-held tools

• Advanced NDE

• Structural monitoring (short and long-term)

• Non-accessible elements/components

• Load capacity evaluation/rating tools

• Turning inspection data into useful decision-

making information


Extreme Events

• Earthquake

• Flood

• Wind

• Impact (vehicle, ship/barge)

• Fire

• Blast

• …..


Adaptable to Change

• Traffic demands

• Climate change

• Age (repair, rehab)


Overarching Issue…

Data Information


Selected current FHWA projects that address

issues.


FHWA Research Mechanisms

• Contract R&D…consultants, universities,

others

• In-House FHWA Laboratories

– Structures

– Geotechnical

– Hydraulics

– Aerodynamics

– Non-Destructive Evaluation (NDE) Center

– Durability (Paint/Coatings/Corrosion)


UHPC for Modular Bridge Connections

SR 31 over Canandaigua Outlet

Lyons, New York

61 in. 6 in.

Closure Pour (UHPC)

Deck Bulb Tee Prestressed Girder

41 in.

6 in.

Closure Pour (UHPC)

Precast Deck Panel8 in.

96 in.

SR 23 over Otego Creek

Oneonta, New York


FHWA-AASHTO Joint Study (NCHRP 12-84)


I-35W Bridge

Collapse


I-35W Bridge Collapse

• Among the questions raised:

– Performance of gusset plates

– Gusset plate evaluation and rating

– Gusset plate inspection

[determination of corrosion or remaining section

of multiple plate systems]

**Design error…not fatigue, corrosion or inspection.


Limit State Performance


Phase 2 Test Matrix – Corroded Specimens


Corrosion Between Multiple Plates

• Inaccessible; conventional NDE does not work

• Technologies being assessed include:

– Pocket UT (Ultrasonic Portable C-Scan Imaging

System)

– Phased Array Ultrasonic Testing

– Active IR Thermography

– Portable Radiography


Corrosion in Concrete Bridges

• NDE methods being assessed:

– Microwave (Thermo) Reflectometry

– Ground Penetrating Radar (GPR)

– Ultrasonic Echo / Impact Echo

– Infrared (IR)

– Half Cell / Linear Polarization


NDE Technologies for Hidden Wire Corrosion

NDE technologies are being

evaluated for corrosion detection

in PT external tendons, stay

cables, and suspension cables


Long-Term Bridge Performance Program

(LTBPP)

• Designated in “SAFETEA-LU” surface

transportation authorization legislation (August

2005)

• Intended as a long-term research effort to

improve our knowledge of bridge performance


Tools for

Program Objectives


• Detailed inspection, periodic evaluation and

monitoring by taking advantage of sensor

technology

• Representative sample of “work-horse” highway

bridges

• Forensic autopsies of decommissioned bridges

• Leverage accelerated testing when possible

Program Approach


• Sept. 2009 – Sept. 2011

• Detailed inspection and

monitoring of 7 bridges

• Validate protocols

and processes

• Coordinate with SHAs

for field investigation

Pilot Bridge Location

Pilot Bridge Study


LTBPP Pilot Bridges

• 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


• Continuous built-up steel girder

• CIP concrete deck

• AADT of 16,500 with 6% truck

traffic

Virginia Utah


LTBPP Pilot Bridges


• Single span multi-beam steel girder bridge

• CIP concrete deck, stay-in-place forms

• AADT of 25,000


• 2-span Pre-stressed post-tensioned

continuous CIP Box Girder bridge

• AADT of 24,500 with 21% trucks

California New Jersey


Activity VA UT CA NJ MN NY FL

Bridge Selection Done Done Done Done Underway Underway TBD

Finite Element Model Done Done Done Done Future * Future * Future *

Live Load Testing Done Done Done Done Future * Future * Future *

Visual Inspection Done Done Done Done Future * Future * Future *

NDE Deck Survey Done Done Done Done Future * Future * Future *

Coring & Physical

TestingDone Done Done Done Future * Future * Future *

Analysis of Results Underway Underway Underway Underway Future * Future * Future *

* Anticipated

Completion date:

03/31/2011

LTBPP Pilot Study Status


• Improved knowledge of State maintenance effectiveness

• Demonstration of effectiveness of sensor technology in

bridge inspection/condition assessment

• Improved bridge life-cycle cost analysis and deterioration

prediction

• Basis for implementation of performance based design

• Protocols for load rating based on structural monitoring

• Foster the next generation of bridge and asset

management systems and tools

Anticipated Impacts of a 20+ Year Program


Continuing Research Needs

• Risk-based Inspection Approaches

• Inaccessible Component Inspection Technology

• Remote Inspection and Visualization

• Sensors and Systems

– Short-term performance evaluation

– Long-term performance monitoring

– Motorist warning


• Rapid Load Capacity Assessment

• Underwater Inspection/Imaging

• SHM Data Fusion and Knowledge Tools

• Fire-resistant materials

• Improved welding processes (speed, quality,

consumables)

• In-situ stress/strain measurement

More Needs…


Thank you…questions?

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