Life-Cycle Cost Comparison of Corrosion Management Strategies for Steel Bridges

Abstract

Corrosion of metals is one of the primary factors leading to the deterioration of bridge structures in the US. Protective coatings applied to the surface of the metal have been widely used as a corrosion protection system for steel bridge components. Because the coating also can deteriorate over time, other strategies, such as using steels with better corrosion resistance (i.e., weathering steels), have also been adopted. A recently developed structural stainless steel has shown better performance than conventional weathering steels, particularly in harsh environments, but it comes with a high initial cost. The aim of this study is to compare the life-cycle costs (LCCs) of various corrosion management strategies for bridge steel structures, using either coated carbon steel or structural stainless steel. To evaluate the structural performance of the coated carbon steel structure, a new probabilistic corrosion model is developed for the first time that explicitly incorporates the coating degradation in the steel deterioration process. Using two case studies, this study compares the LCCs of cyclical- and condition-based maintenance strategies and investigates the impact of different coating systems on the LCC. The results show that the structural stainless steel may be more economically beneficial than coated carbon steel, but the payoff time depends on the parameters used in the LCC analysis, such as the maintenance strategies adopted for the coated carbon steel, the coating type, the discount factor, and the size of the structure considered.