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This article presents analysis of deterioration indicators for a comparative quantification of the operational structural performances of bridge inventories. The analysis considers the various kinds of material in the entire database of the US National Bridge Inventory. The multi-criteria approach integrates the indicators of deterioration, considering diagnostic condition and life cycle to determine the equivalent operational structural performances. This study also uses reconstruction data to determine an additional deterioration indicator for performance. The proportional effort for reconstruction reflects the practical need to counter deterioration and preserve a required level of structural performance, under all circumstances. The presented addition of reconstruction performance provides a more comprehensive assessment of bridge performance. The results reveal the continuous efforts to maintain a relatively balanced performance adequacy at the national level within the prevailing funding constraints. Reconstruction performances are generally higher than deterioration trends (rate and pattern) performances, revealing that the constrained reconstruction efforts have difficulty to keep pace with the actual deterioration. [ABSTRACT FROM AUTHOR]

Reinforcement bars in concrete are exposed to several actions, such as overloading, fatigue, and corrosion. These actions can lead to a deterioration of the reinforcement bars. However, only advanced stages of damage in the reinforcement will be visible at the surface. Since no suitable commercial nondestructive methods are available yet, the concrete cover must be removed if damage is suspected. The magnetic flux leakage method is a promising approach to solving this problem. A measuring device was developed that enables the simultaneous magnetization of the reinforcement and measurement over a width of 20 cm. To support the user, a software is in development that allows for immediate evaluation and interpretation of the results. The present project aims at demonstrating the value of the magnetic flux leakage method in particular for bridge evaluation. [ABSTRACT FROM AUTHOR]

This paper demonstrates a comprehensive national network-level analysis to determine the relative deteriorations and operational structural performances of the various types of bridge structural design and/or construction. The study analyzes the entire database of the U.S. National Bridge Inventory for the year 2013 and considers bridge counts along with bridge deck areas that provide more significant results. Analysis of the proportional distribution of structural deficiency reveals issues of deterioration. Considering the structural deficiency, service life cycle and deterioration trends of bridge types over time, the multi-criteria equivalent structural performances incorporate the condition, durability, longevity, rate and pattern performances. The results provide support for more sustainable engineering and management decisions. Stringer/multi beam or girder (type 02) bridges are the most common bridge type, 40.75% by counts and 61.88% by areas. The structural performance of type 02 bridges seems comparable to the average of all bridges, yet they have lower durability and longevity performances, revealing a relative service life cycle vulnerability. The lowest structural performances are orthotropic (type 08) and segmental box girder (type 21) bridges; while their condition performances are rather high, their durability, longevity, rate and pattern performances are essentially low. The slight improvement of structural performance from 2006 to 2013 for most bridge types is not significant over seven years. Also, certain bridge types worsened.

This study analyzes the National Bridge Inventory in the U.S. to determine the relative structural deficiencies of bridge materials, comparing between the overall national values and each state, geographically. The analysis considers the most common bridge construction materials—concrete, steel, and prestressed/post-tensioned concrete. The results suggest need to reassess the efficacy of best performance practices for steel bridges and for states with structural deficiencies above the national average. Geographic consistency of structurally deficient bridge density with population density shows need to improve intervention strategies for regions with higher levels of service usage. The study also compares the relative operational lifespan of bridge materials in each state. The average structurally deficient bridge ages are lower than the 75-year life-cycle expectancy. Prestressed/post-tensioned concrete bridges reveal relatively lower lifespan. Over time, concrete and steel bridges show some gradual improvement with decreasing percentage of structural deficiency and increasing lifespan. Prestressed/post-tensioned concrete bridges reveal shifting earlier accumulation of structural deficiency for a particular age group. The study also reveals relative climate effects. Climate conditions correlate differently with the structural deficiency and life cycle of bridge materials in each state. Structurally deficient bridge densities show correlation with climate maps, especially under colder and moist conditions.

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. [ABSTRACT FROM AUTHOR]

This paper demonstrates the analysis of the deterioration trends of bridges to evaluate the operational structural performances of the various kinds of bridge construction materials and/or structural designs. The goal of this study is to improve the performance of structural materials used to construct bridges, based on rigorous population-based analysis of the performance of those materials in service. The analysis uses the raw database of the entire National Bridge Inventory in the United States and derives material deterioration aspects at the serviceability limit states. The study develops measures of deterioration to consider the trends in the accumulation of structural deficiency versus service life cycle by material. The approach defines the criteria of rate and pattern performances to analyze the comparative deterioration trends. A multiple-criteria diagnostic approach determines the overall equivalent structural performances integrating the rate and pattern performances with the measures of condition, durability, and longevity. The national network-level operational experience by categorical deterioration trends produces the most comprehensive comparative basis of structural performance of bridge materials. Overall for all bridges, the average increase of structural deficiency is 0.51%/year, adding to the already existing 12.35% and consisting of an average annual increase of structurally deficient bridges by 4.10%. The accumulation of structurally deficient bridges begins only after 10 years for most materials. The rate and pattern performances of almost all of the materials are quite poor. Thus, the equivalent performances integrating the deterioration trends are lower. The results provide a more objective indication and comparison of structural performances under the actual circumstances and help predict future performance. The approach supports the development of improvements necessary to increase the relative performances of distinct bridge materials for more sustainable service. [ABSTRACT FROM AUTHOR]

This paper demonstrates trends in bridge structural deficiency and evaluates the operational structural performance of various types of bridge structural design and/or construction. The study analyzes the database of the National Bridge Inventory and derives data based on actual bridge deck areas, rather than discrete bridge counts. Based on the concept of structural deficiency and the objective of life-cycle expectancy for uninterrupted service life, the multiple-criteria diagnostic analysis determines condition, durability, longevity, and equivalent performance. For some bridge types, the results reflect limited remaining service life before structural deficiency is reached. Average service life is only 56% of life-cycle expectancy. The relatively higher condition performance contrasts with the significantly poor performance of durability and the relatively lower longevity. The equivalent structural performance of some bridge types is low. Overall, the study provides an indication of the current average potential, which serves as a basis for predicting future performance under similar operational conditions. The systems approach supports more objective design, maintenance, and decision-making practices, leading to more effective operation and management and more sustainable infrastructure solutions. [ABSTRACT FROM AUTHOR]

This paper evaluates the operational structural performances of the various kinds of bridge construction materials and/or structural designs, considering the deck areas of bridges, rather than their discrete counts. Deck areas represent more objectively the actual constructed capacity in the inventory and the traffic mobility. The study compiles and analyzes the entire bridge inventory in the United States. The analysis uses multiple-criteria diagnostic measures to determine the condition, durability, longevity, and overall equivalent performances. The results provide a comprehensive national network-level comparative basis for bridge material performances at the serviceability limit states. Nearly 99% of all the bridge areas in the inventory have average structural deficiency ages significantly lower than the official life-cycle expectancy. The durability performances indicate that the average service life before structural deficiency is only 42 years. The relatively high condition contrasts with the low durability and longevity performances, reflecting the efforts to improve the condition of bridges. Overall, the average equivalent structural performances of bridge materials by deck areas are quite low, and even lower as compared with performances by bridge counts. [ABSTRACT FROM AUTHOR]

The diagnostic concept of the structural deficiency of bridges is an essential engineering and management consideration with implications of performance. The structural deficiency analysis reflects the constructed system performance at the serviceability limit states. This paper analyzes trends in the structural deficiency of bridge inventory on the basis of material kind. A multiple-criteria diagnostic approach defines measures for condition, durability, and longevity performances and determines the overall equivalent performance. Thus, the structural performance levels reflect the structural reliability and vulnerability indices for bridge serviceability. The application of the approach analyzes the raw database of the entire bridge inventory in the United States. This comprehensive operational experience provides a national network-level comparative basis. The comparison suggests a relative need for improvements in one or more areas, such as design details or maintenance level, to increase the desirability of bridge construction materials. The results support more objective bridge management and decision making on distribution of funds, updating of policies, perfection of practices, and trade-off analyses for design, construction, maintenance, and replacement. [ABSTRACT FROM AUTHOR]

This paper demonstrates the analysis of the deterioration trends of the various types of bridge structural design and/or construction in the entire U.S. National Bridge Inventory, to derive and compare operational structural performances. The approach considers the trends of the proportional accumulation of deterioration by bridge types, based on the concept of structural deficiency and the objective of life-cycle expectancy at the serviceability limit states. The analysis determines the rate and pattern of the deterioration trends. The multiple-criteria diagnostic approach integrates the rate and pattern performances with the condition, durability, and longevity performances to determine the overall equivalent structural performances using prioritized weights. This study produces the most comprehensive national network-level comparative basis of the operational structural performances of bridge types under the actual circumstances. The deterioration trend performances of most bridge types are relatively lower. Also, the overall equivalent structural performances of almost all bridge types are lower. The analysis also helps identify critical accumulation of deterioration for bridge types, suggesting focused improvement efforts necessary for existing and future bridges. The most common stringer/multibeam or girder bridges have relatively higher and faster accumulation of deterioration, generating a below average trend and equivalent structural performances. The results help predict future performances and improve effectiveness of bridge types for sustainable service life. [ABSTRACT FROM AUTHOR]