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One of the key tasks to ensure infrastructure safety is the periodic detection of bridge cracks. Since manual crack detection is subjective and inefficient, it is very important to develop an automatic crack recognition system by using machine vision. Inspired by the pyramid vision transformer (PVT) and the feature pyramid network (FPN) variants, a method combining PVT, residual transformer (REST), holistically nested edge detection (HED), and downstream detection tasks is proposed in this paper, which is named EVPTMFF (efficient visual pyramid transformer and multiple-feature fusion). Based on the PVT, the multiheaded attention module was replaced and the efficient attention module was adopted, which could process the data efficiently and flexibly. To improve the performance of EVPTMFF, the original perceptual field windows were changed. The adjacent windows were partially overlapped, which was more conducive to feature interaction and improves detection performance. To prove the generalization ability of the model, three different data sets related to bridges were collected and formed. We carried out experiments on these three data sets, and EVPTMFF showed good results. Especially for larger data sets, the performance advantage was more significant. Practical Applications: The crack detection model proposed in this paper presents a good detection effect under different illumination and interference. And the detection results, collected data, time, and other information are saved to the bridge crack detection software. This can help engineers quickly and accurately detect cracks on the bridge surface, as well as predict the development trend of cracks and possible safety issues. In practical application, the bridge crack detection system can help engineers find and solve the bridge crack problem in time and avoid the security risks and economic losses caused by cracks. At the same time, the efficiency and accuracy of bridge maintenance can be improved, and the maintenance cost and time can be reduced. The bridge crack detection system can be integrated with other hardware equipment and management systems to form a complete bridge management platform, which contributes to the traffic construction and social and economic development of the city. [ABSTRACT FROM AUTHOR]

Uncoated weathering steel (UWS) is used for bridges to minimize maintenance costs incurred due to possible steel corrosion. State highway departments often use weathering steel for bridges with the expectation that the weathering steel structure will not corrode. Weathering steel has improved corrosion-resistant behavior over conventional steel; however, weathering steel is not maintenance free and will corrode if not used in correct ambient conditions and properly maintained. Consequently, weathering steel retards corrosion but may require future restoration through cleaning and/or applying surface coatings. The Arkansas Department of Transportation (ARDOT) bridge inspection inventory includes 859 UWS bridges. Approximately 11% of these bridges have some level of oxide film degradation, AASHTO defect code 3430. These bridges are located throughout the state. Other states have also experienced this condition, resulting in state highway departments facing the dilemma of how to restore weathering steel sections that have experienced corrosion. This article reviews the extensiveness and severity of oxide film degradation at UWS bridges in Arkansas, the prevalence of UWS oxide film corrosion in other states, how oxide film corrosion progresses as a function of time, and remediation measures. [ABSTRACT FROM AUTHOR]

To support bridge management systems (BMSs) in establishing strategic maintenance plans to preserve the condition of aging bridges, it is important to estimate a bridge component's future condition reliably. To this end, many data-driven studies have attempted to apply diverse algorithms and explore major factors influencing the condition of specific components. Despite these efforts, it is still difficult to construct a robust and generally applicable condition estimation model for bridge components regardless of the characteristics of the BMS data because BMS data become heterogeneous and complex by period, region, or country. Therefore, the objective of this study is to develop an optimized condition estimation model for bridge components using data-driven approaches. To achieve the main objective, the proposed model included the following elements: (1) outstanding algorithm selection by comparing the performance of diverse algorithms; and (2) influential variable identification by utilizing the recursive feature elimination (RFE) method according to the permutation variable importance. Based on a case study to estimate the condition grades of decks on concrete-girder bridges using the Korean Bridge Management System (KOBMS) data, extreme gradient boost (XGBoost) was selected as the optimal algorithm, and influential variables were identified such as "bridge age" and "first past condition grade of deck." Finally, the optimized model based on the integrated results of the algorithm selection and the influential variables identification showed good performance with an average weighted average F1 score of 0.876. The outcome of the research will contribute to reliably estimating the future condition of bridge components by constructing an optimal model suitable for each BMS data and supporting strategic maintenance decisions based on the expected components' condition for proactive bridge management. [ABSTRACT FROM AUTHOR]

Even with the continuous development of coating technologies, coating systems are susceptible to corrosion-induced premature failures and unable to meet the anticipated service life. Coating premature failures will negatively impact the safety, integrity, and longevity of steel bridge structural elements. The advancement of the data analytics approach (e.g., machine learning) offers an opportunity to leverage the wealth of historical bridge inspection and maintenance data collected by Departments of Transportation to evaluate coating conditions of steel bridges effectively and efficiently. This paper focuses on presenting a data-driven study that analyzes the conditions of coating systems of steel bridges in the state of Florida. Three machine learning algorithms were used in developing models that can be used to analyze steel bridge coating conditions based on data collected from the Bridge Management System of the Florida Department of Transportation. The result showed that the machine learning–based models were able to effectively predict steel bridge coating conditions. The k -nearest neighbor (KNN) regression algorithm offered the best performance. Although the approach was currently applied to the steel bridges of Florida, it can be easily replicable for similar data sets from other states. The research contributes to the body of knowledge by offering a data-driven understanding of coating performance of steel bridge elements. The research has the potential to offer a valuable decision-making tool for transportation agencies to effectively and easily analyze or predict steel bridge coating conditions. [ABSTRACT FROM AUTHOR]

For through tied-arch bridges, the corrosion and degradation of the cable's load-bearing capacity are the main external causes of cable breakage and subsequent structural failure; nevertheless, the progressive collapse after cable breakage is primarily attributed to the weak structural robustness, which makes a huge potential risk of bridge operation and maintenance (O&M). Whereas, as the basis of O&M, current condition evaluation method has not yet taken into consideration the influence of different consequences of cable breakage, resulting in unscientific conclusions for O&M decisions frequently. In this study, a robustness-based condition evaluation framework for the overall structure of the through tied-arch bridge is presented, consisting of three stages: (1) structural robustness assessment associated with tie-bar and suspender failure respectively; (2) classification of evaluation process by the results of robustness assessment, within which the overall structure is either evaluated using the code method or evaluated directly as unqualified (Condition I and II), or the structural member weightings are adjusted according to the robustness weightings (Condition III); and (3) condition evaluation of entire bridge. The evaluation processes of three conditions are further presented in accordance with the tied-arch structure and suspended deck system. To establish the robustness weightings in Condition III, the safety redundancy indexes of through tied-arch structures as well as the suspended deck system are calculated separately, combined with robustness assessment result. Applying the proposed framework to evaluating the condition of a through tied-arch bridge with different structures, the analysis and comparison indicates that, due to the robustness of the through tied-arch structure and suspended deck system, the variation in the potential risk of accidents induced by cable failure is shown intuitively through the evaluation results, which better meets the needs of guiding bridge O&M decisions consequently. [ABSTRACT FROM AUTHOR]

Extensive investigation of rapid-repair materials is of utmost importance in limiting the impact of repairs on vehicles traveling on bridges as well as in selecting suitable materials with acceptable mechanical properties and durability requirements. The objective of this study was to evaluate eight commercial cementitious rapid-repair materials for application to concrete bridge decks in Utah. A robust laboratory study to quantify mechanical performance and durability was been conducted, accompanied by evaluation of field performance. More than 450 specimens were prepared according to manufacturer recommendations and tested at ages of 4 h, 24 h, 7 days, and 28 days to measure their setting time, compressive and splitting tensile strength, elastic modulus, autogenous and drying shrinkage, restrained ring shrinkage, surface resistivity, and slant/shear bond strength. To evaluate the field performance of the materials, repair patches on the SR-193 bridge over US-89 in Layton, Utah, were inspected three times over a one-year period and crack developments on these patches were recorded. The purpose of the study was to identify the most influential factors in the success or failure of deck repair materials and to determine which tests are most helpful in the qualification of deck repair materials. The results will assist transportation officials, such as state departments of transportation (DOTs), in identification and qualification of materials to support successful and long-lasting bridge deck repairs. [ABSTRACT FROM AUTHOR]

Due to the constraints of structural bearing, guardrail elevation, and milling depth of cement-paved bridge deck, the white-to-black maintenance of concrete bridge deck always has been a technical problem in road maintenance. This paper proposes a technical solution to the maintenance of concrete bridge deck by using a hot-mixed ultrathin wearing course. The road performance and construction technology were studied. The results of indoor performance tests show that the residual stability of Marshall immersion tests and the ratio of freeze–thaw splitting strength were greater than 90, and the rutting dynamic stability was 4,786 times/mm , with better water stability and high-temperature performance. The results of engineering application show that the effect of application of hot mixed ultrathin wearing course in the white-to-black maintenance project of the concrete bridge deck is meaningful, and the test results of the performance indexes such as the skid resistance, flatness, and water seepage of the pavement are excellent. However, it is necessary to create drainage channels on the bridge deck. [ABSTRACT FROM AUTHOR]

Deformations due to environmental and mechanical loads in curved bridges can lead to fairly complex long-term effects. Instead of the one-dimensional longitudinal movement that occur in straight bridges, in curved bridges two-dimensional movements, i.e., longitudinal and transverse, need to be considered in the design stage and throughout the structure's life span. Both deformations are related to the curvature and construction materials used in the bridge. Currently, both guided and nonguided bearings commonly are deployed to accommodate the movement and stresses caused by thermal movements in curved bridges. Bearings usually are oriented along the chord from the fixed piers of the bridge in current design practice. However, this traditional orientation is not compatible with bridge movements at each pier, which can induce excessive stresses in both superstructure and substructure. This study monitored and investigated a steel twin-box girder bridge. The fracture-critical bridge analyzed in this study lies on four horizontal and three vertical curves. Guided and nonguided expansion pot bearings are utilized, except on the fixed pier. Extreme temperature changes caused transverse superstructure movements and damage to the bearing guiding system. The monitoring system outfitted on the bridge recorded the temperature distributions as well as the bridge movement. The structural movement behavior due to temperature variation was studied, and the investigation of existing damage showed that both transverse and longitudinal movement were excessive and that the resultant forces transferred from superstructure to substructure were significant. The results indicate that a refined analysis always is required to account for curved bridges' deformations in order to prevent structural damage. [ABSTRACT FROM AUTHOR]

This paper is intended to review the main causes and mechanisms of bridge collapse. The common factors resulting in bridge collapse are first reviewed. These factors are classified into two broad categories, namely, natural factors (including flood, scour, earthquake, landslide, debris flow, hurricane, typhoon, wind, etc.) and human factors (including imperfect design and construction method, collision, vehicle overloading, fire, terrorist attack, lack of inspection and maintenance, etc.). Then the collapse modes of a few major types of bridges are reviewed and some relevant measures adopted in the current practices are discussed. It is hoped that this paper will provide a concise but comprehensive summary of information needed by researchers and engineers to understand the collapse mechanisms of the major bridge types and how the current practices deal with these issues. Meanwhile, much effort is made to identify future research needed to better understand this topic and to find better solutions to address the existing issues. [ABSTRACT FROM AUTHOR]

This paper provides a risk-based assessment of the sustainability of structural design alternatives in hazard-prone regions. Little systematic research has been done to assess the economic, social, and environmental cost of sustainable construction in relation to hazard resilience or the impacts of hazard-resilient design on system sustainability. However, some studies have suggested that green construction practices might compromise the objective of the design of hazard resistance of a building, whereas others have highlighted that the impacts of natural hazard damage are unsustainable, given the costs of reconstruction and threats to public safety, among other consequences. This paper extends the performance-based engineering paradigm beyond traditional metrics of structural performance to quantify such sustainability metrics as monetary cost, embodied energy, emissions, casualties, and downtime. The upfront environmental and economic costs of sustainable design alternatives are then compared with hazard-induced risks, considering uncertainties stemming from the hazard, damage assessment, or sustainability analysis. The sustainability analysis is illustrated for both bridges and buildings sited in seismically prone regions, revealing the potential trade-off in upfront costs and lifetime sustainability attributable to hazard exposure. [ABSTRACT FROM AUTHOR]

One of the most important tasks of a civil engineer as a bridge inspector is the structural assessment of cracks on bridge decks and their supporting structure. Although the work seems to have low value, the financial impacts on the bridge owners of getting it wrong can be significant. This paper summarizes what every civil engineer working as a bridge designer or inspector should know about undertaking and interpreting crack surveys in typical unreinforced concrete or masonry abutments in short- and medium-span bridges. A methodology is introduced that may be used to increase the validity and reliability of all decisions concerning the crack significance and associated remedial works. [ABSTRACT FROM AUTHOR]

Current Bridge Health Index (BHI) in Pontis Bridge Management System applied to assess the bridge health conditions for 615 bridges in city and county of Denver (CCD) does not provide CCD engineers a valuable analysis of the health condition of its relatively small bridge network. This paper explores both the calculation results and the computing methodology of the current BHI. The BHI was computed for the entire 615 CCD bridge network using the two current cost-based methodologies. Based on the analysis, it was concluded that the current BHI is subjective to a municipality's often imprecise cost data. This coupled with the methodology of heavily correlating cost with a bridge's condition reveals potential for modification to meet the needs of the CCD. The results of this study are used as a basis for developing an alternate BHI methodology. [ABSTRACT FROM AUTHOR]

Current bridge health index (BHI) in Pontis bridge management system applied to assess the bridge health conditions for 615 bridges in the city and county of Denver (CCD) does not provide CCD engineers a valuable analysis of the health condition of its relatively small bridge network. Both the calculation results and the computing methodology of the current BHI reveal that it is subjective to a municipality's often imprecise cost data. This paper focuses on developing an alternate BHI. In order to understand the principle and procedure of the BHI calculation, the element weighting point was developed as a new concept in the analysis. The study concluded that the weighting point should reflect the effect of element damage on bridge health and function instead of a percentage of element value. Based on this conclusion, the current BHI was modified. The Denver BHI, a new diagnostic tool, was developed. It has already been adopted in the Pontis bridge management system of the CCD public works department. [ABSTRACT FROM AUTHOR]

Accurate prediction of bridge condition is essential for the planning of maintenance, repair, and rehabilitation. An examination of the assumptions (for example, maintenance independency) of the existing Markovian model reveals possible limitations in its ability to adequately model the procession of deterioration for these purposes. This study uses statistical analysis to identify significant factors influencing the deterioration and develops an application model for estimating the future condition of bridges. Based on data derived from historical maintenance and inspection of concrete decks in Wisconsin, this study identifies 11 significant factors and develops an artificial neural network (ANN) model to predict associated deterioration. An analysis of the application of ANN finds that it performs well when modeling deck deterioration in terms of pattern classification. The developed model has the capacity to accurately predict the condition of bridge decks and therefore provide pertinent information for maintenance planning and decision making at both the project level and the network level. [ABSTRACT FROM AUTHOR]

This paper reports on the monitoring and repair of a pilot field deployment of a glass fiber-reinforced polymer (GFRP) deck on a small steel girder bridge in the Washington State. Deck deflections were monitored periodically over a 10-month period and were found to increase significantly over that time. The GFRP deck is an adhesively bonded assembly of GFRP tubes and top and bottom plates. After 9 months of service, wearing surface cracking was observed, and upon closer inspection, the top GFRP plate was found to be delaminated from the tubes over a fairly large area. Deck deflections in the area of delamination were found to be considerably larger than those observed during previous monitoring in undamaged locations. A retrofit solution was employed where the top plate was reconnected to the tubes using screws coated with a two-part epoxy that mixed when they were driven. At the time of writing the retrofit was successful in reattaching the delaminated top plate. [ABSTRACT FROM AUTHOR]

Advancements in fiber-reinforced polymers (FRPs) have made this an attractive material for rehabilitation and strengthening of bridge superstructures. FRP has primarily been used with the intention of increasing the bending strength of bridge members. However, this paper investigates the use of externally placed FRP strips to increase shear capacity of short-span, 5.7 m(19 ft), precast concrete channel beam bridges. A statewide survey revealed that as many as 389 bridges in the state of Arkansas are comprised of these members. Notably, beams within these bridges were designed under provisions that did not require shear reinforcement. In this research, four sections were retrofitted using carbon fiber-reinforced polymer (CFRP) strips and load tested to failure to measure the repair effectiveness. The performance of the retrofitted sections far exceeded that of unretrofitted sections. It was concluded that the addition of the CFRP repair increased the deflection ductility at least 123%. In addition, beams retrofitted with the CFRP strips experienced at least 26% more deflection after the initiation of a shear crack; therefore reducing the risk of a catastrophic failure. [ABSTRACT FROM AUTHOR]

Usually the status of a bridge is determined by its structural capability and material strength. Consequently a lot of researchers have studied the failure, the fatigue, and the deterioration of the structure in terms of the structural function of a bridge. However, the safety of a bridge may be affected simply by the damage of one of its components. Therefore this paper utilized a systematic classification and statistical analysis based on the thousands of sets of existing bridge inspection data collected in Taiwan to reach the following goals: (1) assess the deterioration rate for each component of a bridge; (2) determine the lifetime of each component based on the performance index; and (3) find out the preventive and essential maintenance strategy for each bridge component with an empirical method. [ABSTRACT FROM AUTHOR]

The results of a multifaceted investigation into large-amplitude vibrations of bridge stay cables are presented. The vibration of the stay cables occurred under light rain and wind conditions, and resulted in low-frequency, large-amplitude oscillations having recorded displacements of over 24 in.(0.6 m). Due to concerns about the implications of the vibrations on the integrity and durability of the stay cables and observed damage to stay-cable anchorage components, an investigation and repair program was developed. The final repair program arose from an investigation that combined the talents of practicing engineers, the Texas Department of Transportation, and representatives from four universities. Ultimately, a combination of supplemental hydraulic dampers and cable restrainers were used to mitigate the vibrations. This paper describes the results of the investigation and presents the practice-based methodology used to develop the implemented repair program. [ABSTRACT FROM AUTHOR]

Safety of a highway infrastructure system depends very much on the proper maintenance of bridges. The level of required maintenance is, typically, determined through a series of regular field inspections with the guidance of safety–economy trade-off. In Turkey, bridge maintenance, repair, and rehabilitation are currently performed on an as-needed basis. Time-dependent reliability analysis cannot be utilized for Turkish bridges for the time being since the majority of the bridges are either not regularly inspected or not inspected at all. The purpose of this paper is to propose a simple method to assess the remaining service life of a bridge by defining a relationship between its current condition rating and its age by evaluating a set of bridges at different ages. In a case study, 28 bridges were inspected for the first time to assess the average life expectancy. The average life of a bridge was predicted to be 80 years, and for this set of bridges, the main body components were found to deteriorate more than earth retaining and serviceability components. [ABSTRACT FROM AUTHOR]

Durable repairs of bridge piles exposed to a marine environment require a proper repair design, which includes understanding and preventing the deterioration mechanism in such environments and proper construction methods. To understand how repair systems work, it is important to recognize which deterioration mechanism the system prevents and controls. Conversely, to understand why a system does not work, one must determine the deterioration mechanisms that the system failed to control. The deterioration mechanism should be addressed before repair construction starts so that an appropriate solution can be achieved. Also, construction practices that accelerate deterioration mechanisms should be recognized and avoided. This paper describes efficient construction methods that can be incorporated in the construction of bridge pile repairs. It also gives recommendations to increase the life of a bridge pile repair by analyzing deterioration of repaired structures, defining the cause of deterioration, providing suggestions to enhance the performance of the repair by practical and feasible actions, and giving an integrated approach to bridge repair construction processes. [ABSTRACT FROM AUTHOR]

The City and County of Denver (CCD) Public Works Department owns, inspects, and maintains 531 bridges in its inventory of which 264 are considered major structures spanning over 6.1 m in length. In this paper, a methodology using the CCD major bridge network for the application of nondestructive evaluation (NDE) methods in bridge inspections is explained. The methodology, called Bridge Evaluation using Nondestructive Testing (BENT) helps systematically integrate NDE methods and conventional bridge management systems by using a Markovian deterioration model. Although the BENT method can be applied to timber, steel, and concrete bridges, in this paper the application of the method will be restricted to concrete bridges. The BENT system is part of a comprehensive geographic information system whereby database queries can be completed using a map interface. The database contains a wide array of information in the CCD infrastructure inventory including bridges, pavements, alleys, and street subsystems. [ABSTRACT FROM AUTHOR]

The 1995 Hyogo-ken Nanbu (Kobe), Japan earthquake provided the world’s first experience with earthquake damage to new long-span bridges designed to 1990s seismic standards. This paper reviews damage and describes techniques used to repair three major steel bridges along the Wangan route (Bayshore route) in Kobe—the 885 m Higashi-Kobe Bridge, the 217 m Rokko Island Bridge, and the 252 m Nishinomiya Port Bridge. These bridges, in service for less than three years, were essential components in the highway transportation system in the Kobe region. Extremely large ground motions, and failure of bearings, connections, and seismic restrainers were principal contributors to the damage sustained by these bridges. Repairs utilized heavy-lift floating cranes (up to 4,100 ton capacity) and various jacks to stabilize the structures and to realign spans. In one case, reconstruction of a collapsed span was required, with lifting weight a prime concern. Significant constraints on the repair included confined working space and requirements for maintaining maritime navigational clearances. The closure times for the repair of the bridges ranged from three to nine months. [ABSTRACT FROM AUTHOR]

Comments on the the article "Bridge Management and Nondestructive Evaluation" by Kevin L. Rens et al, which was published in the February 2005 issue of the journal. Shortfalls of bridge evaluation using nondestructive testing (BENT) methodology; Proposed solutions to BENT problems; Reasons for not using nondestructive evaluation technology in the project.