Which issue was observed on the I-276 Delaware River-Turnpike Toll Bridge?

• A. T1 steel butt weld failure
• B. Impact damage
• C. Overloaded gusset plates
• D. Rivet hole filled with wellment started a crack

Answer: (D)

Cracking in steel bridge connections often starts at a stress concentration, such as a rivet hole, especially when that hole has been altered by filler material. In this scenario, the rivet hole was filled with a substance described as wellment. Filling a rivet hole can trap moisture, create a mismatch in material properties, and introduce a rough interface around the hole. Under repeated traffic loading, this local irregularity becomes a fatigue crack initiation site and can propagate from the edge of the filled hole into the surrounding steel.

So, the observed issue on the I-276 Delaware River-Turnpike Toll Bridge fits a fatigue-crack scenario initiated at a rivet hole that had been filled with filler material. This is why it’s the best choice: it points to a specific, crack-related problem tied to a rivet-hole modification, rather than to a broad or different failure mode like butt-weld issues, impact damage, or gusset overload, which would present differently in inspection findings. In practice, this would lead to targeted inspection of riveted connections, assessment of the filler’s suitability, and repair actions to remove the filler or repair the affected area to restore proper detailing and remove the crack initiation point.