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Fatigue Resistance of Welds With and Without Reinforcement


Fatigue Resistance of Welds With and Without Reinforcement

Current situation:

For tension members in fatigue situations, the American Association of State Highway and Transportation Officials Load Rating Factor Design (AASHTO LRFD) Bridge Design Specifications require CJP butt joints to be ground flush. However, the AWS D1.1 Structural Welding Code, requires that for similar situations, welds be finished in the direction of tensile stress and the diagram indicates some reinforcement can remain. Problem: Requiring butt joints to be ground completely flush with adjacent base metal expends significant labor and equipment time, delaying fabrication, adding heat to the weld zone, and may result in over-grinding requiring welded repair.

Research proposal:

Perform fatigue testing on CJP butt joints with limited reinforcement remaining, ground per the AWS D1.1 requirements, and compare with previous results for welds ground flush. Extensive test data exists for fatigue of flush ground butt joints, so only welds with reinforcement would be tested.

Potential benefits:

If the fatigue tests prove that butt joints with limited reinforcement ground to a prescribed surface roughness provide fatigue resistance nearly identical to flush ground joints, the AASHTO LRFD code could be amended, saving significant costs for steel bridge fabrication.

Submitted By:

Jon Edwards


Sponsoring Committee:AKC70, Fabrication and Inspection of Metal Structures
Date Posted:05/05/2013
Date Modified:05/07/2013
Index Terms:Bridge design, AASHTO LRFD Bridge Design Specifications, Welds, Failure, Butt joints, Tensile strength, Reinforcement (Engineering),
Cosponsoring Committees: 
Subjects    
Construction
Design
Materials
Bridges and other structures

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