I-5 Skagit Bridge was reported to have which type of damage?

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

Answer: (C)

Impact damage describes a sudden, external load event such as a vehicle strike or debris impact that causes localized deformation or damage to a member or connection. For the I-5 Skagit Bridge, the observed signs were consistent with damage from a strike, rather than gradual failure from fatigue, corrosion, or a weld defect. You’d expect to see things like denting, bending, or deformation near the affected joint or member, possibly with damaged connections, rather than the progressive cracking typical of fatigue or the widespread material loss from corrosion. A wear or crack pattern from an overload of service loads would look different and wouldn’t center on a discrete impact zone. Similarly, a weld-specific failure would present cracks or defects at welds rather than a damage signature from a collision. So the reported issue fits the profile of impact damage.