Steel structures, such as hydraulic structures and ships operate in harsh wet and corrosive environments and can suffer significant deterioration. The deterioration typically manifests itself in the form of corrosion, fatigue cracking, or a combination of both. While corrosion or cracks are typically viewed as a nuisance, if left unrepair, they can threaten the integrity of the structure.
Repairing these fatigue issues using the conventional repair methods have proven to be ineffective because the traditional repair techniques were developed to work with pure tension cracks (Mode I) and not cracks that grow as a consequence of tension and shear stresses (Mix Mode). Recent studies on the use of Carbon and Glass Fibers Reinforced Polymers (CFRP and GFRP) to retrofit structures under mix mode loading have demonstrated to be a viable solution for increasing fatigue life of structures made of metals such as miter gates, lift gates, and reverse tainter valves.
With the above mentioned motivations, the studies to evaluate the viability of using CFRP to repair underwater metal structures were used to repair fatigue cracking in Old Hickory Lock and Dam miter gate at the Cumberland River and a reverse tainter valve at Pickwick Lock and Dam in the Tennessee River. The presentation will focus on the best practice to be implemented to make these repairs successful for navigation steel structures. Other composites, such as basalt, are under investigation and will also be briefly described in this talk.