Where Metalizing Struggles: Challenges on In-Service Steel Bridges

Thermal spray coating (TSC), or metalizing, generally delivers exceptional longevity on steel bridges in atmospheric marine environments, yet field application on in-service structures poses distinct challenges. This article examines the practical difficulties of field-applied TSC on a fixed-girder bridge metalized with 99.5% aluminum (Al) and a bascule bridge metalized with an 85% zinc (Zn)/15% aluminum alloy. The article discusses critical points in the design and inspection of TSC, as well as commonly observed issues with feed-stocks, overspraying, and surface distress at complex geometries, particularly in bridge infrastructures.