Steel Bridge Structures Research Articles

Study on the degradation of axial tensile performance of corroded bolts in steel bridges

As crucial connecting components in steel bridge structures, high-strength bolts are susceptible to corrosion from environmental factors such as corrosive agents in the air and rain during long-term service. This corrosion can reduce their load-bearing capacity, thereby threatening the safety of the entire structure. Most studies assess the degree of corrosion through mass loss, but lack a comprehensive quantitative analysis of its impact on mechanical performance. This study investigates the axial tensile performance degradation of corroded bolts based on fractal characteristics of the corroded surface and tensile mechanical performance experiments. By analyzing the fractal dimensions of corroded surfaces, which ranged between 2.026 and 2.053 for more severely damaged threads, a strong correlation was established between surface corrosion and tensile performance degradation. Bolts were classified into three categories based on fractal dimension, which quantitatively reflected the degradation of bolt tensile performance. finding that the ultimate tensile strength and load-bearing capacity decreased by 2.5–6.8 % and 1.25–5.5 %, respectively. Notably, the load at 75 % displacement dropped from 390 kN to 340 kN, a reduction of over 15 %.Finite Element Method (FEM) was used to simulate the bolt tensile process, and experimental data were used to fit damage-plastic constitutive models for bolts with different corrosion levels. The Void Growth Model (VGM) fracture criterion was employed to simulate bolt tensile fracture, predicting the axial tensile performance degradation of bolts with varying corrosion levels, and established a correction formula to quantify the impact of fractal dimension on the ultimate tensile strength of corroded bolts.This study provides a new approach for assessing corrosion impact and predicting the axial tensile performance of bolts in service.

Thermal cycles, structure and properties of welded joints in structural steels during welding in extreme cold conditions

The article summarizes research on the thermal cycles, structure, and properties of welded joints made from low-alloy and low-carbon steels during arc welding in sub-zero temperatures. This review aims to analyze previous research to create solid recommendations for welding steel bridge structures during winter conditions. The results of a comparison of experimental measurements of thermal cycles of welding samples with different sizes made at room and subzero ambient air temperatures (down to minus 50 °C) are considered. It is shown that in small plates with dimensions of 200 × 250 × 10 mm, due to more intense heat reflection from the edges of the specimen, the thermal cycles of welding at different temperatures do not differ significantly. In more massive samples (sized 450 × 250 × 10 mm), an increase in the cooling rate of the overheated welded joint area is observed compared to room temperature welding. The impact of hydrogen on the development of cold cracks in low-alloy steels during welding at temperatures below freezing is examined. Metallographic analysis has revealed that the structural changes that occur during the welding of various steel grades are notably different and are influenced by the steel’s chemical composition as well as the thermal cycle parameters of the welding process. Dilatometric studies indicate that variations in the levels of alloying elements within different grades significantly influence the kinetics of austenite transformation. Therefore, to identify the best welding techniques for subzero temperatures, it is essential to consider not just how heat disperses in these conditions, but also the kinetics of phase changes and their effects on the structure and properties of the products resulting from austenite decomposition.

Experimental and Numerical Analysis of an Innovative Combined String–Cable Bridge

Suspension bridges, such as stress-ribbon, are among the simplest structural bridge systems and have the lowest structural height. The flexibility of these elegant bridges poses great challenges for designers to minimize their deformability under asymmetrical operational loads. Due to the small initial sag, such load-bearing structures also cause significant tensile forces, which requires them to have large cross-sections and massive anchor foundations. This paper analyzes an innovative suspension steel bridge structure combined with a string and a cable. More attention is paid to asymmetric loading as this is more relevant for suspension structures. The new structure is studied numerically and experimentally. It is established that the string stabilizes the displacements of the bridge under asymmetric loading. The stabilization efficiency is proportional to the value of the pre-tension force of the string. The obtained results reveal the behavior of the structure and enable an evaluation of the accuracy of the numerical results, as well as the applied modeling. In addition, the experimentally obtained results allow the evaluation of more aspects of the behavior of the new bridge, which will be useful in further studies of this type of structures.

Fatigue performance of bonding‐assisted fillet weld roots by inserting adhesive material

AbstractThis study proposes a novel method to prevent fatigue cracks at the root of fillet welds in steel bridge supports by inserting epoxy resin as an adhesive material. A total of 36 specimens, categorized into welded‐only and bonding‐assisted types, were subjected to a series of four‐point bending fatigue tests to simulate cyclic tensile stress conditions. Additionally, finite element analysis was employed to investigate the impact of epoxy insertion on stress distribution near the weld root. The results demonstrated that bonding‐assisted specimens exhibited significantly improved fatigue life compared to welded‐only specimens, with a notable reduction in tensile stress at the weld root. Furthermore, a displacement‐based method was employed to evaluate weld root fatigue performance, yielding consistent results. These findings highlight the potential of integrating adhesive bonding in fillet welds to improve the durability and service life of steel bridge structures by effectively mitigating fatigue‐related issues.

Study on Steel and Concrete Composite Structure Bridge

Study on Steel and Concrete Composite Structure Bridge

Fire effect of steel bridge structure with consideration of leaked combustion fuel on asphalt bridge deck

In this paper, a fire load model is introduced for steel bridge decks considering asphalt pavement layers, aimed at exploring the consequences of fire arising from fuel leakage on the bridge pavement. Temperature data, mass loss rates, and radiation measurements from the pavement during fire tests are collected. The fire process on the bridge deck is categorized into four distinct stages, based on the mass loss rate. The temperature-time model is constructed by fitting the temperature data from the first two stages on the top surface. This model is then validated by comparing the temperature data obtained from various temperature-time load inputs with the experimental data from the middle and bottom surfaces. Additionally, a finite element numerical model is developed for a steel box girder bridge, enabling a comparison of different temperature-time models to establish the rationality of the bridge deck temperature-time model. Finally, the thermal mechanical coupling method is employed to investigate the impact of fire on the bridge's mid-span, revealing a close alignment between the simulation temperatures derived from the bridge deck temperature-time curve and the experimental results.

ДОСВІД ЕКСПЛУАТАЦІЇ ТА ОСОБЛИВОСТІ РОБОТИ ВОДОПРОПУСКНИХ СПОРУД ІЗ МЕТАЛЕВИХ ГОФРОВАНИХ КОНСТРУКЦІЙ НА АВТОМОБІЛЬНИХ ДОРОГАХ

Introduction. Road culverts made of metal corrugated structures despite of more than a hundred years of application history, in Ukraine they are a fairly new type of construction and are widely used in transport construction as an alternative to traditional steel or concrete bridge structures. The well-known advantages that justify the choice of such a solution are mainly a short term and relatively low cost of construction, construction provided that the appropriate technological regime is followed and does not cause any particular problems. However, the modern process of design and construction of road culverts from metal corrugated structures is imperfect and is constantly being improved. Therefore, there is a need to conduct an analysis conditions of operation and features of the operation of road culverts from the metal corrugated structures with the determination of approaches to improving design and construction to further increase the durability of the structure as a whole. Problems. From the literature analysis, it was established that road culverts are in difficult operating conditions, which causes their premature destruction. Goal. It consists in the analysis of operating experience and features of the operation of culverts made of metal corrugated structures on highways with the installation of measures to increase durability.

Accurate Detection Method of Corrosion State of Steel Structure Bridge in Internet of Things Environment Based on Visual Image Characteristics

Abstract Bridge structures are one of the most important aspects of transportation because they make remote areas accessible, but preserving the environment is equally important. The toughness and endurance of the bridge structure is very important from the security perspective of transportation. Corrosion adversely impacts the steel structure strength of bridges. Accurate detection methods within the environment of Internet of Things can help to find the corrosion of bridges in time, take maintenance measures in advance, and delay the decay of bridge life. At present, the inspection of bridge supports is primarily carried out by labor-intensive inspection. This method is time-consuming and labor-intensive and also affects traffic. To show advancement in the detection accuracy of the bridge corrosion state, an accurate detection method based on visual image features is proposed. Drone technology is used to collect corrosion images of steel bridges. Considering the complexity of the image, the convolution operation is performed on the images using a deep neural network (DNN). A DNN model is constructed according to the apparent features of the rust image. The supervised learning DNN is combined with the unsupervised learning sparse autoencoding (SAE), and the DNN is autoencoded by SAE to reduce the reconstruction bias. On this basis, the accurate detection of the rusted state is accomplished. From the experimental analysis, it is apparent that the peak signal-to-noise ratio of this method is higher than 25, and the detection time is shorter than that of the methods compared. It can accurately detect different types of rust states.

Low cycle fatigue behavior and life prediction of a directionally solidified alloy

Low cycle fatigue behavior and life prediction of a directionally solidified alloy

Experimental Analysis of Static and Dynamic Performance for Continuous Warren Truss Steel Railway Bridge in Heavy Haul Railway

Continuous Warren truss steel railway bridges are one of the main forms of railway bridges. Due to the deterioration of materials and the long-term effect of loads, the bridges will inevitably experience performance degradation, which may lead to the failure of the bridge structure to continue to operate. In order to study the mechanical properties of steel structure bridges after material deterioration and long-term loads, a continuous Warren truss steel railway bridge that has been in operation for nearly 30 years (built in 1996) is used as the research object, and a combination of field tests and finite element (FE) simulations are used to carry out research on its mechanical properties under different loads. The research results show that after nearly 30 years of operation, the steel structure bridge has local damage, but the bearing capacity still meets the requirements of heavy-duty traffic. At this stage, the corrosion of the steel structure and the damage of the bearing should be repaired in time to prevent the damage from expanding.

Weathering steel bridge structure after 30 years of service ‐ assessment experience

AbstractThe structure of 531.4 m total length bridge was made in early nineties last century and it was regarded as novelty by that time. The interesting point was that the structure was made of original Polish weathering steel prepared for bridge solutions intently. There were several trouble concerning the bridge service, steel cracks and less than expected patina growth due to the unfavorable conditions inside the box girder. Quite recently the bridge was carefully inspected as it was to be an important issue of the modern motorway. There was a question if the bridge is to be demolished, due to the corrosion and structural problems or to be preserved and extended to meet required traffic volume. There was a careful examination performed including metallurgical, corrosion and structural analysis done. The paper is to present the most important outcomes concerning mainly structural issues, but some weathering steel corrosion observation will be provided as well.

Fatigue & Fracture of Engineering Materials & Structures Virtual Special Issue: Data science and machine learning for fatigue and fracture assessment

<scp>Fatigue &amp; Fracture of Engineering Materials &amp; Structures Virtual Special Issue</scp>: Data science and machine learning for fatigue and fracture assessment

A Review on Analysis of Damage Diagnosis and the Vibration Characteristics of Steel Bridge Structures

Cracks or crevasses in girder steel bridges caused by moist environmental issues such as corrosion have the possibility of causing structural destruction, resulting in the loss of unanticipated events, assets, and human life. This obliteration can be overlooked if cracks are resolved early. The cracks in the bridge girder alter its strength and vibration characteristics. The current study examines various studies in the field of crack detection/damage detection that have been conducted using various numerical and experimental techniques. Analysis of finite elements (FEA) can be highly useful in protecting a structure from damage and cracks. The review deals with the investigation of damage commencing from environmental exposure conditions which can be studied via various numerical and experimental investigations by means of simulation techniques. By dint of these software-aided techniques, the research can be carried out in a simple and effortless manner. FEA enables engineers to conduct the simulation of a designed model rather than creating a physical model for testing. The current study looks at the effect of damage initiation and propagation using software-operated techniques The Applications of finite element methodology, which requires a software package for dynamic simulations, are presented and highlighted in terms of innovation and future research in studying crack attributes of natural and mode shapes.

BEHAVIOR OF PRE-STRESSED INTERSECTING CABLE STEEL BRIDGE

Cable-stayed bridges are known as one of the most effective and graceful forms of bridges. The main problem in the design of cable-stayed steel bridges is their deformability, especially under asymmetrical loads. Stabilization of the initial form of cable-stayed bridges can be achieved by selecting the appropriate cross-sectional area of the cables and their pre-stressing, as well as by increasing the cross-sectional height of the stiffness beam. However, a greater effect can be achieved by applying new forms of such bridges. Solutions for such bridges with an atypical arrangement of cables and additional pylons are already applied in practice. The article discusses an innovative pre-tensioned intersecting cable steel bridge structure system. The behavior of this bridge system under permanent and temporary loads is analyzed. Based on the performed numerical experiment, the efficiency of the innovative cable-stayed steel bridge system was determined. This newly designed bridge system is more effective in terms of stress and displacement distribution than a classic cable-stayed bridge system.

Ways to solve welding problems of bridge structures for arctic service

The problems of material selection for steel bridge structures for arctic service and welding of such structures in pre-fabricated conditions and at sites are considered. The sources for the research included data on the requirements for steels for the manufacture of metal bridge structures for arctic service, the specifics of their welding, control of structure formation and mechanical properties of welded joints. The main reason for the insufficient impact strength at low temperatures is the presence of microcracks on the grain boundaries of the metal crystal structure, the cause of which is the presence of phosphorus and sulfur impurities in structural steels. To improve cold resistance properties, welding modes should be chosen in such way, that liquid metal stays for the minimum amount of time at the melting point of iron sulfide on the grain boundaries of the metal crystal structure. The necessity of engineering comparative analysis with the application of modern research methods of available methods for welding of bridge structures for arctic service is shown.

Experimental study on the verification of adequate fatigue test specimen size of U‐rib‐to‐deck joints in orthotropic steel bridge decks

AbstractIn this study, the distribution of residual stress of the substructure model and small coupon specimens in orthotropic steel bridge structures is experimentally and numerically investigated to validate adequate specimen sizes. Blind‐hole drilling and X‐ray diffraction methods are used to capture longitudinal and transverse residual stresses and evaluate the effects of the cutting process. The maximum LRS and TRS were reduced by 16.6% and 15.6% from those that existed before cutting, verifying the proper size of small voucher specimens. The width‐to‐thickness ratio of 6–6.25 of small coupon specimens has proven sufficient to capture the effects of stress triaxiality induced by the residual stress. In the spirit of master S‐N curves in ASME standard, the role of residual stress was represented in the fatigue process and does not be additionally taken into account when predicting the fatigue performances of welded structures using prediction methods based on the S‐N curves.

Properties of Structural Steels in Historical Railway Bridges by Diagnostic Tests

AbstractOver their long service life, steel bridge structures are subjected to functional and material degradations. As a result, these bridges require periodical investigation and assessment of their current resistance. This should be done according to the recommendations of the European Convention for Constructional Steelwork (ECCS), in force since 2008. The paper presents the technical condition of 13 steel bridges built between 1873 and 1890 and 17 bridges from the years 1907 to 1983. The age division given above is prescribed by the great changes in technology and materials which appeared at the turn of the 20th century, the development of structural steel and the appearance of modern higher strength steels in bridge constructions. The mechanical properties of the steels and their chemical compositions are given. The steel test results and conclusions may be useful for others investigating historic steel bridges.

Structural Health Monitoring of Fatigue Cracks for Steel Bridges with Wireless Large-Area Strain Sensors.

This paper presents a field implementation of the structural health monitoring (SHM) of fatigue cracks for steel bridge structures. Steel bridges experience fatigue cracks under repetitive traffic loading, which pose great threats to their structural integrity and can lead to catastrophic failures. Currently, accurate and reliable fatigue crack monitoring for the safety assessment of bridges is still a difficult task. On the other hand, wireless smart sensors have achieved great success in global SHM by enabling long-term modal identifications of civil structures. However, long-term field monitoring of localized damage such as fatigue cracks has been limited due to the lack of effective sensors and the associated algorithms specifically designed for fatigue crack monitoring. To fill this gap, this paper proposes a wireless large-area strain sensor (WLASS) to measure large-area strain fatigue cracks and develops an effective algorithm to process the measured large-area strain data into actionable information. The proposed WLASS consists of a soft elastomeric capacitor (SEC) used to measure large-area structural surface strain, a capacitive sensor board to convert the signal from SEC to a measurable change in voltage, and a commercial wireless smart sensor platform for triggered-based wireless data acquisition, remote data retrieval, and cloud storage. Meanwhile, the developed algorithm for fatigue crack monitoring processes the data obtained from the WLASS under traffic loading through three automated steps, including (1) traffic event detection, (2) time-frequency analysis using a generalized Morse wavelet (GM-CWT) and peak identification, and (3) a modified crack growth index (CGI) that tracks potential fatigue crack growth. The developed WLASS and the algorithm present a complete system for long-term fatigue crack monitoring in the field. The effectiveness of the proposed time-frequency analysis algorithm based on GM-CWT to reliably extract the impulsive traffic events is validated using a numerical investigation. Subsequently, the developed WLASS and algorithm are validated through a field deployment on a steel highway bridge in Kansas City, KS, USA.

Mechanical Degradation of Q345 Weathering Steel and Q345 Carbon Steel under Acid Corrosion

In this work, a mechanical degradation of weathering steel and carbon steel caused by strong acid corrosion has been studied in order to clarify the threat of industrial acid vehicle leakage to steel structure bridge. Twenty-seven specimens of Q345 weathering steel plates and Q345 carbon steel plates were immersed in a 36% hydrochloric acid solution at room temperature, with the corrosion time being 0 h, 1 h, 2 h, 4 h, 8 h, 12 h, 24 h, 48 h, and 72 h, respectively. Subsequently, the obtained specimens were subjected to a uniaxial tensile test to determine the stress-strain curves. The surface morphology was studied by the noncontact surface topography instrument DSX500. By analyzing the degree of mechanical degradation, the constitutive models of test steels under strong acid corrosion were established. The analysis of results shows that the corrosion rate of carbon steel is higher than that of weathering steel. After 72 hours of corrosion, the mass loss rate of carbon steel and weathering steel was 4.77% and 4.30%, respectively. The maximum corrosion pit depth of carbon steel was 25.52 μm higher than that of weathering steel. The constitutive models were in good agreement with the test results, and the resistance to corrosion degradation and deformation of the weathering steel was higher compared to the carbon steel. The results can serve as a guideline for designing steel constructions of improved durability.

Formalising the R of Reduce in a Circular Economy Oriented Design Methodology for Pedestrian and Cycling Bridges

The construction industry consumes over 32% of the annually excavated natural resources worldwide. Additionally, it is responsible for 25% of the annually generated solid waste. To become a more sustainable industry, a circular economy is necessary: resources are kept in use as long as possible, aiming to reduce and recirculate natural resources. In this paper, the investigation focuses on pedestrian truss bridges of the types Warren and Howe. Many pedestrian bridges currently find themselves in their end-of-life phase and most commonly these bridges are demolished and rebuilt, thus needing a lot of new materials and energy. The aim is thus first and foremost to reduce the amount of necessary new materials. For this reason, a design tool will be created, using the software ‘Matlab’, in which truss bridges can be evaluated and compared in the conceptual design stage. The tool is based on the theory of morphological indicators: the volume indicator, displacement indicator, buckling indicator and first natural frequency indicator. These allow a designer to determine the most material efficient Warren or Howe truss bridge design with user-defined constraints concerning deflection, load frequency, buckling and overall dimension. Subsequently, the tool was tested and compared to calculations made in the finite element modelling software Diamonds. In total, 72 steel bridge structures were tested. From these it could be concluded that the manual calculations in Diamonds in general confirmed the results obtained with the automated design tool based on morphological indicators. As such, it allows a designer to converge more quickly towards the best performing structure, thus saving time, materials, and corresponding costs and energy.