Deterioration Trends and Structural Performances of Bridge Types Using Deck Areas: Fid-Bau Portal

Deterioration Trends and Structural Performances of Bridge Types Using Deck Areas

Farhey, Daniel N.

This paper demonstrates the analysis of the relative deterioration trends of the various types of bridge structural design and/or construction to determine and compare their operational structural performances at the serviceability limit states. The study derives operational data from the entire database of the U.S. National Bridge Inventory and analyzes the actual bridge deck areas rather than bridge counts. Deck areas more realistically reflect the actual sizes of bridge types, enabling a more reliable analysis of deterioration trends and providing more objective structural performances. The study analyzes the trends of the proportional accumulation of deterioration by bridge type, considering criteria based on the concept of structural deficiency and the objective of life-cycle expectancy for uninterrupted service life. The multiple-criteria diagnostic approach integrates the rate and pattern performances, based on deterioration trends, with the condition, durability, and longevity performances to determine and compare the overall equivalent structural performances using prioritized weights. As compared to inventory averages, the results reflect the distinct deterioration trends of bridge types and show a decrease in the equivalent structural performances by 10%. As compared to counts, the equivalent structural performances by areas are lower by 3% for all bridge types and 34–40% for some bridges. Also, the annual maximum average accumulation of structural deficiency of all bridge areas is nearly 20% lower than by counts. The average increase in structural deficiency is 0.42% per year, adding to the already existing 9.38% and constituting an average annual increase of structurally deficient (SD) bridge areas by 4.48%. The analysis also identifies premature accelerated accumulation of deterioration for a particular age group within a bridge type, indicating a critical need to investigate the etiology of the deterioration and improve existing and future bridges. The study provides a comprehensive national network–level comparative experience of the operational structural performances of bridge types by area under actual practices and circumstances to help identify critical deterioration, forecast future structural performance, and promote the sustainability of bridge types.