Development of performance-based deterioration models for bridge components

Abstract This study examines bridge component deterioration patterns in Idaho, USA, using National Bridge Inventory (NBI) data collected from 1983 to 2023. A total of 5774 bridges were analyzed, representing 69 combinations of construction materials and structural system designs. The study focused on six common bridge types: prestressed concrete slab, prestressed concrete girder, concrete frame, concrete slab, concrete girder, and steel girder bridges. Kaplan–Meier survival analysis was applied to generate survival curves and assess deterioration over time. The results revealed that prestressed concrete girder, steel girder, and concrete girder bridges exhibited slower deterioration and retained higher condition ratings over time. In contrast, prestressed concrete slab and concrete slab bridges showed faster early deterioration, while concrete frame bridges experienced moderate deterioration patterns. A multiple regression analysis was also conducted to evaluate the influence of various factors on deck deterioration. Bridge age, freeze–thaw cycles, and snowfall days were found to be significant predictors of deterioration. In contrast, bridge length, span length, and average daily traffic (ADT) had minimal effects. The reduced model explained 89.4% of the variance in deterioration outcomes.