Steel Bridge Maintenance Research Articles

Optimized deep learning for steel bridge bolt corrosion detection and classification

Corrosion of steel bridge bolts poses a major threat to structural integrity. As a key component, bridge bolts are susceptible to corrosion and detachment, necessitating close monitoring during maintenance. However, the vast number of corroded bolts presents challenges. Conventional detection relies on subjective visual inspection without unified assessment criteria. Fast and accurate localization and classification of bolt corrosion levels thus became a research priority for bridge maintenance. This study puts forward a new two-stage corrosion detection method, integrating Deep Convolutional Generative Adversarial Network (DCGAN) and improved You Only Look Once version 5 (YOLOv5) networks, which enables rapid categorization of bridge bolts by different corrosion extents, providing an intelligent solution for bridge maintenance. First, in the image preprocessing stage, a DCGAN with least squares loss generates simulated corroded bolt images through adversarial learning to expand the dataset. Second, three corrosion levels are defined based on visual features and percentage of surface rust, with this classification scheme applied in dataset annotation. Finally, the annotated images are input into an enhanced YOLOv5 model named YOLOv5-SE for corrosion identification. To improve accuracy, Squeeze-and-Excitation blocks are added after each residual block in the YOLOv5 backbone. Comparative experiments prove YOLOv5-SE's superior performance over YOLOv5 and other models like Faster R-CNN and VGG16. A pytorch system enables model deployment for corrosion detection. The integration of DCGAN simulation and attention-optimized YOLOv5-SE enables precise classification and localization of corroded bolts. This study represented a significant step towards intelligent upgrades in steel bridge maintenance.

Digital Twin-driven framework for fatigue life prediction of steel bridges using a probabilistic multiscale model: Application to segmental orthotropic steel deck specimen

Accurate fatigue life prediction facilitates the fatigue maintenance of steel bridges. Since Digital Twin can simulate the lifecycle for physical objects at various scales, this study aims to provide a Digital Twin-driven framework for non-deterministic fatigue life prediction of steel bridges. A probabilistic multiscale model was developed to depict the fatigue evolution throughout the bridge lifecycle. The small crack initiation period was well described by the modified Fine and Bhat model considering microstructure uncertainties. After obtaining the critical model parameter via crystal plastic finite element simulation, the modified model was further calibrated using the assumed historical fatigue data in Digital Twin database. Based on the initiated half-penny-shaped small crack, the small crack initiation period was connected to the macrocrack extension period. Given the uncertainties of macrocrack propagation, the Paris’ law with random growth parameters was adopted. The Bayesian inference of the growth parameters realized the real-time calibration of the macrocrack growth model using Markov chain Monte Carlo simulation. The feasibility of the proposed framework was demonstrated through fatigue tests on a segmental steel deck specimen with mixed-mode deformed U-rib to diaphragm welded joints. The results show that the predicted fatigue initiation life and residual fatigue life are in good agreement with the experimentally observed life results. In summary, the proposed framework enhances our understanding of the fatigue evolution mechanism throughout the bridge lifecycle and provides an entirely new approach to accurately predict the fatigue life of steel bridges under various sources of uncertainties.

Sustainability of bridge maintenance

Bridge maintenance activities are important to consider within sustainable development due to the cost and environmental impact associated with various maintenance activities. Comparisons have been made between different bridge structural forms, based on materials, components and construction method, but less information is available on bridge maintenance activities to help decide a sustainable structural form. Typical maintenance aspects of the predominant forms of bridge structure (i.e. concrete, steel and masonry bridges) were considered in this study to reveal their sustainability in terms of materials, energy, transportation, human health and ecosystems. The results indicate that concrete and steel bridge maintenance activities have an average impact of 42% and 46% compared with 12% for masonry bridge maintenance activities. It is concluded that the component parts of concrete and steel bridges should be revised as they play an integral role in the selection of maintenance options.

Probabilistic optimization of fatigue maintenance for welded components in steel bridges based on LEFM and LCCM

In this paper a probabilistic-based method for fatigue maintenance optimization of steel bridge’s welded joints, combined with linear elastic fracture mechanics (LEFM), the structure reliability, and life cycle cost method(LCCM) is proposed. The probabilistic analysis method can be used with the fatigue maintenance of steel bridges. Weld cracks are classified by its size and maintenance decisions, and are made according to its size classification. Maintenance cost is divided into inspection, repair and failure costs, according to the life cycle cost method. The maintenance optimization strategy is transformed to minimize the expected lifetime total costs with the constraints of the minimum acceptable reliability index to attain the most cost-optimal inspection and repair for the balanced costs between risk and safety. An example concerning the transverse stiffeners of welded components in the main girder of suspension bridge is investigated through the research of some parameters sensitivity. Among all the parameters, the inspection cost is the most remarkable. The optimal time interval of repair will delay based on the increase of the inspection cost. The optimal time interval of repair will advance based on the increase of repair cost. A discount rate can drastically change the value of the total cost, but when the probability of failure is very small, the increase of failure cost has little effect on the optimal time interval of repair. The method presented in this paper can be conducted using the similar maintenance of steel structures.

Determination Method of Bridge Rotation Angle Response Using MEMS IMU.

To implement steel bridge maintenance, especially that related to fatigue damage, it is important to monitor bridge deformations under traffic conditions. Bridges deform and rotate differently under traffic load conditions because their structures differ in terms of length and flexibility. Such monitoring enables the identification of the cause of stress concentrations that cause fatigue damage and the proposal of appropriate countermeasures. However, although bridge deformation monitoring requires observations of bridge angle response as well as the bridge displacement response, measuring the rotation angle response of a bridge subject to traffic loads is difficult. Theoretically, the rotation angle response can be calculated by integrating the angular velocity, but for field measurements of actual in-service bridges, estimating the necessary boundary conditions would be difficult due to traffic-induced vibration. To solve the problem, this paper proposes a method for determining the rotation angle response of an in-service bridge from its angular velocity, as measured by a inertial measurement unit (IMU). To verify our proposed method, field measurements were conducted using nine micro-electrical mechanical systems (MEMS) IMUs and two contact displacement gauges. The results showed that our proposed method provided high accuracy when compared to the reference responses calculated by the contact displacement gauges.

Rapid and automated determination of rusted surface areas of a steel bridge for robotic maintenance systems

There has been an increased interest in the use of robotic systems to automate the blasting tasks in steel bridge maintenance. To utilize such robotic systems effectively, an automated process for determining the rusted areas on a steel bridge to be blasted is a prerequisite. This study proposes a method to rapidly and accurately determine rusted surface areas on a steel bridge that are to be blasted, within current standards. The proposed method consists of three steps: color space conversion, classification of rusted area via the J48 decision tree algorithm, and determination of blasting area. The method was validated using 119 test images showing both normal states and various degrees of rusting and rust distribution types. The experimental results showed that the success rate for determining the rusted areas that needed blasting was 97.48%. The average processing time was 0.57 s/image. The results demonstrate that the proposed method rapidly and accurately indicated whether blasting was necessary, and if so, where blasting should be performed, based on current standards of practice. • This study proposed a method to determine which rusted surface areas to be blasted. • Performance of the method was evaluated on 119 images acquired from steel bridges. • The success rate was 97.48% and the average processing time was only 0.57 s/image. • The method is fast, accurate, and in compliance with current standards of practice. • The method could be employed in robotic systems used for steel bridge maintenance.

An effective exploration approach to simultaneous mapping and surface material–type identification of complex three‐dimensional environments

AbstractThis paper presents an integrated exploration approach for geometric mapping and surface material–type identification of complex three‐dimensional (3D) environments using a six‐degree‐of‐freedom industrial robot manipulator. Maps of the surface geometry with the surface material type identified are required for an autonomous robotic system to perform operations in steel bridge maintenance. The proposed approach utilizes information theory to enable multiobjective exploration while new 3D geometric and surface‐type data are fused via probabilistic updates. It is verified that the integrated approach enables the robotic system to perform exploration and surface inspection in real‐world environments. © 2009 Wiley Periodicals, Inc.

Capacitive sensor for object ranging and material type identification

This paper presents a system for object ranging and material type identification using a multifrequency approach for a capacitive sensor. It is shown through an experimental study that the deviation in the readings taken at different sensor drive frequencies and the variation in consecutive readings provide sufficient information to distinguish a range of material types commonly found in a number of environments. A supervised learning scheme is used to classify the material type of planar patches. Extensive experimental evidence is presented to demonstrate the potential of the system. The capacitive based, object penetrating, material type identification is targeted for use with an autonomous robotic system for steel bridge maintenance; significantly different interaction is required for each of the various materials present. Experimental results demonstrate that the information from the sensor is sufficient to range and identify the material type (via physical properties) of an object present in a scene where a bridge structure is being grit-blasted.

Maintenance of steel bridges on Honshu-Shikoku crossing

This paper describes maintenance technologies of Honshu-Shikoku bridges in Japan. The Honshu-Shikoku bridges feature many long-span cable supported bridges. Akashi Kaikyo bridge is known as the longest-spanned suspension bridge, and Tatara bridge is known as the longest-spanned cable stayed bridge. The Kojima-Sakaide route, the so-called Seto Ohashi bridge, features highway and railway combined structures. Since the opening of the first bridge, maintenance technologies of Honshu-Shikoku bridges have been accumulated for about 20 years. The most important maintenance technology for steel bridges on the sea is how to protect steel members from corrosion. In this paper, as examples of anti-corrosion methods for steel bridges, repainting of bridges by heavy-coated paint, the dehumidification method for the cables of suspension bridges, and the anti-corrosion method for the steel caissons in the sea are described. Furthermore, a monitoring system to detect weld defects in the railway structures related to fatigue problems is described. Lastly, measurement of the static and dynamic behavior of bridges to verify design assumptions on a bridge’s behavior and to ascertain a bridge’s soundness is described.

Fatigue‐Reliability Updating through Inspections of Steel Bridges

A reliability‐based fatigue‐damage‐evaluation procedure developed in the companion paper is extended in this paper to incorporate information from nondestructive inspections (NDI). Since inspections are required at regular intervals, the results from these inspections can be used for fatigue maintenance of steel bridges. The sensitivity and capability of some of the inspection methods, including ultrasonic inspection, are investigated. Inspection information is beneficial; however, it adds uncertainty to the fatigue‐evaluation process. The detectability and the accuracy are the two additional sources of uncertainty in the NDI. The uncertainties in them are quantified. The detection events are classified into three cases, no crack detection, crack detection but without size measurement, and crack detection with the crack‐size measurement. Using the information from k inspections, the distributions of the basic random variables and the corresponding reliability index are updated. Using the information on th...

Welded Highway Bridges†

Synopsis The great majority of highway bridges are of small to medium spans for which plate-girder construction is usual, and it is with these that the Paper is mainly concerned. Factors influencing bridge design generally and welded construction in particular have been briefly surveyed. They include a comparison of the live loads for designing highway bridges in different countries as an explanation for the differences in economy of construction encountered. Reference is also made to the use of welded construction to overcome certain problems concerning the alignment and clearances of bridgework. Since this subject would not be complete without a mention of bridge decks suitable for bridges of this type, the more commonly used designs are included. The welding described is based on good metal-arc welding practice in Great Britain and, associated with this, the characteristics of steels suitable for welded bridgework. Past experience and research in the construction of welded bridges is referred to because it has affected design practice and, in turn, problems connected with fabrication. Since the preparation of economical design is closely related to fabrication, this has been described more fully, together with remarks on testing procedure and inspection. The Paper also describes how the available methods of erection will influence the choice of design and deals with the maintenance of steel bridges, the economics of welded construction, and their influence on the trend towards improved aesthetic merit in bridge building.

WELDED HIGHWAY BRIDGES. (INCLUDES PHOTOGRAPHS).

Synopsis The great majority of highway bridges are of small to medium spans for which plate-girder construction is usual, and it is with these that the Paper is mainly concerned. Factors influencing bridge design generally and welded construction in particular have been briefly surveyed. They include a comparison of the live loads for designing highway bridges in different countries as an explanation for the differences in economy of construction encountered. Reference is also made to the use of welded construction to overcome certain problems concerning the alignment and clearances of bridgework. Since this subject would not be complete without a mention of bridge decks suitable for bridges of this type, the more commonly used designs are included. The welding described is based on good metal-arc welding practice in Great Britain and, associated with this, the characteristics of steels suitable for welded bridgework. Past experience and research in the construction of welded bridges is referred to because it has affected design practice and, in turn, problems connected with fabrication. Since the preparation of economical design is closely related to fabrication, this has been described more fully, together with remarks on testing procedure and inspection. The Paper also describes how the available methods of erection will influence the choice of design and deals with the maintenance of steel bridges, the economics of welded construction, and their influence on the trend towards improved aesthetic merit in bridge building.