Key Findings

• Only approximately 0.2 inch of crack growth and no fracture was observed beyond notch defects cut into the tension flange of a riveted steel deck plate girder bridge span during 875 MGT of heavy axle load traffic at FAST®.
  - No fractures occurred and no cracks propagated in the span when exposed to extreme cold (-60°F) and loaded in the lab to approximately 10 percent over the design allowable stress. ----9+6u96+3
  With a bottom tension flange cover plate completely severed, the same span still did not fracture when loaded to beyond the yield moment of the cross section. The loss of the severed cover plate did not induce visible cracks in other tension flange components. The span yielded in a ductile manner when loaded to more than 2 inches of deflection.
  - A post-test destructive evaluation revealed several fatigue cracks at rivet holes near midspan in a single tension component of the notched girder, which likely would have been undetectable in a field inspection. These cracks did not propagate to all three tension components.
• Typical riveted steel girders fabricated with multiple layered components have an inherent redundancy that may provide a margin of safety beyond what has traditionally been assumed.