Steel Railway Bridges Research Articles

Life Cycle Analysis of a Steel Railway Bridge over the Operational Period considering Different Maintenance Scenarios: Application to a Case Study

In the context of bridge management, three main types of maintenance actions can be considered. Maintenance actions can be taken preventively before the predefined limit condition is reached, or as a corrective measure in case those limits have been reached. The third possibility corresponds to the so‐called “doing nothing” scenario, in which no action is taken on the bridge. To be able to implement preventive maintenance, it is necessary to know the current condition of the bridge, as well as to be able to predict its performance. On the other hand, it is also important to be able to identify potentially threatening events that might occur in the analysis life period. This paper describes an integrated methodology to help bridge managers in defining an efficient maintenance program, considering the specific case of a railway bridge. The novelty of the methodology is focused on updating an existing methodology proposed by COST TU1406, by extending it to railway bridges and also by including the resilience analysis in case of a sudden event occurrence. The analysis considers a multi‐hazard future scenario, in which a flood event occurs while corrosion phenomena were already in place. The results show the feasibility of the proposed methodology as a support for the establishment of an efficient maintenance schedule to prevent bridge severe degradation, as well as to establish recovery plans in case of a sudden event.

Fatigue safety verification of riveted steel railway bridges using probabilistic method and standard S–N curves

Fatigue safety verification of riveted steel railway bridges using probabilistic method and standard S–N curves

Fatigue Reliability Evaluation of Aged Railway Steel Bridges Based on Probabilistic Fracture Mechanics

Fatigue Reliability Evaluation of Aged Railway Steel Bridges Based on Probabilistic Fracture Mechanics

Crossing the Hooghly River near Kolkata in India: a tale of two bridges spanning 130 years

A 415 m long three-span steel railway bridge was built over the tidal Hooghly River near Kolkata in India in 2016. The new Sampreeti Bridge is just 22 m downstream from the 1887 Jubilee Bridge it replaces, which is due to be moved to an outdoor engineering heritage museum. Despite 130 years of engineering advances, the forces of nature proved equally challenging to overcome. As happened previously, a pier caisson was swept away by monsoon rains – twice – and accommodating dynamic loading required adoption of the latest bearing technology.

Influence of the ballasted track on the dynamic behaviour of steel railway bridges

AbstractThe calculated dynamic behaviour of railway bridges during high‐speed traffic differs from the actual behaviour of its bearing structure. In the case of steel railway bridges, dynamic calculations often overestimate the actual vibration responses and therefore lead to uneconomical results. This gap between calculation and measurement constitutes a complex research issue, whereas the consideration of the ballasted track in dynamic calculations has a major influence. Concerning the damping and stiffness properties of the ballasted track there is a wide range of various mechanical models. However, there is no generally applicable track‐structure model for dynamic calculations which reflects reality in a satisfactory way. In their effort to close the gap between calculation and measurement and to develop accurate track‐structure models for dynamic calculations that take into account the dynamic properties of the ballasted track, researchers at TU Wien have developed a large‐scale test facility which allows for specific research of the dynamic behaviour of the ballasted track. This paper describes the operating principle of the test facility and provides insight into the dynamic effects observed in it, in particular with regard to its vibrations and damping behaviour.

Analysis of degradation process of a railway steel bridge in the final period of its operation

This paper presents the problem of assessing degradation process of a selected railway steel bridge in the final period of its operation. Changes in the technical condition of the analysed steel railway bridge in time on the basis of special inspections carried out in 2009–2014 are investigated. The methodology for conducting steel railway bridge assessment in an engineering approach is being presented taking into account conclusions and results from the subsequent special inspections. Moreover, the results of fatigue analysis and assessment of the steel railway bridge, which was put in service in 1933 are discussed. In order to conduct the fatigue analysis and assessment, the deflection of the structure under moving load is measured, as well as the geometry of the structural elements in the support zone is verified. The impact of rolling stock, in particular heavy freight transport, on the bridge degradation process is indicated. It is found that dynamic effects induced by the freight rolling stock reveal a big influence on the rate of fatigue damage process of the bridge. Additionally, the degradation of the considered railway bridge due to the effect of track misalignment is taken into account. Furthermore, the impact of corrosion damage and fatigue on the distribution of stresses in the bridge structure is also discussed.

Fatigue assessment of steel riveted railway bridges: Full-scale tests and analytical approach

This paper describes a double experimental and analytical study of the fatigue behaviour of the Quisi and Ferrandet Bridges, twin 170 m long steel railway bridges constructed between 1913 and 1915 with typical Pratt truss structures and riveted connections. These bridges are part of the Spanish national railway network connecting the towns of Alicante and Denia, one of the key networks in the Valencia Region (Spain). The experimental laboratory investigation involved fatigue testing in one of the ICITECH laboratories at the Universitat Politècnica de València of: (i) a full-scale bridge span and (ii) an upper cross beam from the Ferrandet Bridge. During the tests, Linear Variable Displacement Transducers (LVDTs) and Strain Gauge (SG) sensors were used to capture the possible nucleation and propagation of fatigue cracks. Fatigue test carried out on the cross beam identified: (i) fatigue life of the critical detail, (ii) fatigue hot-spots along the cross beam and (iii) strain redistribution along the riveted element during crack growth. The experimental results from the full-scale bridge were adopted to calibrate an elastic numerical model of the whole structure, which was in turn used to estimate the Quisi Bridge's remaining fatigue life. The definition of the class of detail and remaining fatigue life were calculated by the S–N curves method, according to Eurocode 3, considering the available information on the bridges' loading histories.

Thermal challenges of replacing jointed rails with CWR on steel railway bridges

Visual inspection of a steel truss railway bridge revealed multiple fatigue cracks on the top member of the truss, mainly attributed to the high impact loads of crossing wheels over the jointed tracks on the bridge. The proposal to replace the jointed track with continuously welded rails (CWR) raised a number of issues regarding the thermal interaction of track and bridge, as the bridge experiences extreme temperature variations. Incorporation of high longitudinal restraint between the track and the bridge may increase the risk of track buckling failure at bridge transition zones, since bridge thermal expansion during hot weather can add compressive forces to the rails transferred through the track fastening system. Reducing longitudinal restraining may increase the size of a rail gap resulting from cold weather rail fracture. An optimal longitudinal fastening profile between the bridge and the track therefore is required to mitigate thermal issues both in hot summers and cold winters. To do so, a numerical model of the track and the bridge is developed in Abaqus and calibrated based on the results of tests performed on the bridge and available literature. Three longitudinal fastening profiles between the bridge and the track are introduced in the numerical model and performance of each for mitigating buckling failure and cold weather rail fracture are analyzed. It is concluded that providing 50% resilient fasteners and 50% zero toe load fasteners on each span can be a sound approach to mitigating the thermal issues of CWR tracks on the bridge.

NUMERICAL STUDY OF FLANGE BUCKLING BEHAVIOR OF HIGH-STRENGTH STEEL CORRUGATED WEB I-GIRDERS

Steel plate girders with trapezoidal corrugated webs (TCWPGs) have been used over the last years around the world in many roadway and railway steel bridges as they can introduce several important advantages compared to flat web plate girders. The proper design of corrugated web girders depends mainly on the flexural and shear capacity of them. However, the flexural capacity is more important. Also, not many researchers studied the flexural capacity of such girders especially, when flange local buckling failure type (FLB) occurs in these corrugated web girders. In this paper, the flange local buckling behavior of steel trapezoidal corrugated web girders built up from high-strength steel (HSS) plates has been investigated to get the advantages of both the technique of corrugated web plates (CWPs) and the high-strength steel material (HSSs) together. A new numerical parametric study on four important parameters has been carried out to explain and investigate the flange local buckling behavior of high-strength steel corrugated web girders, considering mainly the influences of the flange to web thickness ratio, unsupported length of the compression flange, the corrugation angle and the initial imperfection magnitude of the compression flange on the behavior of girders with corrugated webs built up from HSSs. Using the commonly used finite element software ABAQUS, the results of the FE models have been obtained to be analyzed and discussed. Finally, some important advices have been introduced to aid the structural engineers to design such girders under flexural loading in economical manner.

Damage Classification of In-Service Steel Railway Bridges Using a Novel Convolutional Neural Network

Damage Classification of In-Service Steel Railway Bridges Using a Novel Convolutional Neural Network

Influence of different pathologies on the dynamic behavior and against fatigue of railway steel bridges

Steel railway bridges built throughout the twentieth century represent a very important asset in the railway lines of the entire European network. These bridges, despite their advanced age, continue to be part of passenger and freight transport networks, that provide transport to a large part of society. Given their advanced age, these structures are prone to present higher levels of deterioration in spite of the maintenance tasks that are carried out.The appearance of pathologies in the wheel-rail contact suppose an alteration in the dynamic behavior of the via-vehicle system. This fact gains importance when they appear in bridges, increasing the number of cycles undergone by the structure, breaking down structural elements.In this paper, the structural dynamic behavior of a metallic bridge with the presence of different pathologies is studied. The study is focused on a metal bridge built during the first half of the twentieth century currently in service. The aim of the article is to evaluate the influence of these elements on the remaining life to fatigue that they present.

Fatigue tests and calibrated fracture mechanics approach for historical riveted steel girders

For historical riveted steel railway bridges fatigue assessment and calculation of the remaining fatigue life based on SN-curves is a big challenge, due to missing traffic data of the past and often unsatisfactory conservative results (no remaining fatigue life, but no fatigue cracks detected). As an alternative, a fracture mechanics approach based on the assumption of an initial crack length and an analysis of the stable crack growth behaviour seems helpful.Within a research project, four dismounted girders of the carriageway of an old steel lattice girder bridge (year of construction: 1908, end of service life: 2018) were used for specific fatigue tests in the laboratory. Starting from artificial notches, initial cracks at the critical positions at the rivet holes of riveted girders were induced and the development of the crack fronts was measured, simulating rivets with and without clamping force. First, the scope and execution of these fatigue tests are presented in the paper, completed by a comprehensive evaluation of the development of the crack fronts. Then a simple fracture mechanics model is presented and calibrated based on the test data. With this model the remaining fatigue life of riveted girders, with high fatigue pre-damage, can be determined for the borderline cases either without or with high clamping forces in the rivets.

Experimental analysis of damping mechanisms in ballasted track on single-track railway bridges

The calculated dynamic behaviour of railway bridges during high-speed traffic differs from the actual behaviour of its bearing structure. In the case of steel railway bridges, dynamic calculations often overestimate the actual vibration responses and therefore lead to uneconomical results. This gap between calculation and measurement constitutes a complex research issue, whereat the consideration of the ballasted track in dynamic calculations has a major influence. Concerning the ballasted track there is a broad range of various mechanical models with different levels of detail and complexity and also widely differing related characteristic values. However, the consideration of its damping and stiffness characteristics in dynamic calculations still entail uncertainties. This paper focuses on the analysis of different damping mechanisms which occur in the ballasted track. The research is based on a large-scale test facility which allows to quantify the ballasted track’s damping and stiffness properties. Concerning the damping properties, the ballasted track shows a predominant frequency dependency and a subdominant displacement dependency, whereby different energy dissipation mechanisms occur under different circumstances. With regard to the stiffness properties, the ballasted track displays a clearly non-linear behaviour contrary to the specifications given in the technical standards. Furthermore, if tested under clearly specified conditions, the ballasted track can even undergo a change toward a liquid state, thereby completely losing its stiffness properties.

Damage Detection Applied to a Full-Scale Steel Bridge Using Temporal Moments

The most common damages in existing highway and railway steel bridges are related to fatigue and are, as reported in the literature, found in the structural system of the bridge deck. This paper proposes a methodology for detecting damaged joint connections in existing steel bridges to improve the quality of bridge inspections. The methodology combines the use of temporal moments from response measurements with an appropriate instrumentation setup. Damaged joint connections are identified by comparing statistical parameters based on temporal moments to a baseline, where the baseline data are established from statistical parameters evaluated for all considered joint connections. Localization of damaged joint connections is performed by utilizing the instrumentation setup. The feasibility of the proposed methodology is demonstrated through an experimental study on a full-scale steel riveted truss bridge with two known damages below the bridge deck, where both damages are identified and localized. The proposed methodology can improve the identification of critical structural damage during bridge inspections and is applicable to open-deck steel bridges.

Study on applicability of two modal identification techniques in irrelevant cases

Study on applicability of two modal identification techniques in irrelevant cases is made in this paper. The following techniques are considered: peak picking based on correlation analysis (PP-CA), dedicated for ambient vibrations and eigensystem realization algorithm (ERA), formulated for free-decay vibrations investigation. Irrelevant cases are found when analyzed signals are different than recommended to a given technique. The study is conducted on examples of two real structures: masonry tower and steel railway bridge. Both cases are diverse in age, material, excitation and vibrations energy. The signals measured on the tower are suitable for the PP-CA technique (ambient vibrations), while the signals measured on the bridge are suitable for the ERA (free-decay vibrations). However, both methods have been applied to both systems. Natural frequencies, mode shapes and damping ratios are identified and the effectiveness of the irrelevant technique is assessed in relation to the results obtained by the relevant method in each case.

Diagnosis of the microstructural and mechanical properties of over century-old steel railway bridge components

The mechanical and microstructural properties as well as durability of more than century-old steel railway bridges that are still widely in use, among others in Poland, have not been well recognized. Ignoring the effect of material and mechanical properties on the operation of an old-steel bridge may eventually lead to the structure’s failure. This study investigates the reliability of a 100-year-old bridge made of wrought (puddled) iron. The aim of this study is to identify the microstructural and mechanical properties of over century-old steel bridge components in relation to the requirements for modern mild steel grades. The paper presents an analysis of the material and mechanical behaviour of a truss railway bridge that had been in operation for over a century. Laboratory tests were performed on samples taken from the component parts of a dismantled railway bridge, i.e. stringers, crossbars, lower belts, stringer bracings and wind bracing. Fatigue, fracture, hardness and tensile tests are performed to estimate the mechanical properties of the investigated steel bridge component parts. Spectroscopy is used to examine the chemical composition of every element. Light optical microscopy and scanning electron microscopy are employed to examine the microstructure of the steel component parts and its non-uniformities. Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) are used to obtain data about the fracture mechanism and the chemical composition of non-metallic inclusions. Microstructural and mechanical results are discussed in relation to modern mild steel grades S355 and S235, which are widely used structural ferrous alloys. Based on the chemical composition analysis, the possibilities of increasing the strength of the bridge by welding methods and the application of fibre-reinforced polymer (FRP) composite materials are discussed. Obtained results add to the body of knowledge about the maintenance, reinforcement and demolition of bridge structures, which is crucial for preventing failure of over 100-year-old steel structures. This research is an introduction to the study on reinforcing old steel structures by FRP composite materials.

Review and Prospect of the Development of Railway Steel Structure in China

China has made great achievements in railway construction since its founding over 70 years ago. Particularly, China’s highspeed railway industry has developed rapidly and become a beautiful national business card over the past 15 years. Steel structures play an irreplaceable and critical role in railway development and are widely applied in long-span railway steel bridges and roof trusses of railway stations. This research reviews and prospects the development of railway steel structures. It reviews the development of railway steel structures from the perspective of material, structure, and project scale, and proposes the development trends of the railway steel structures, namely, lightweight, assembly, informatization, strong durability, and high tenacity. Moreover, the focuses of future development of the railway steel structures are summarized in terms of design, construction, maintenance, and material. The diversification of application areas and environments has posed a series of technical challenges for the railway steel structure development, including weather resistant design, construction in harsh marine environment, and lack of maintenance in plateau environment, which all require persistent and further research.

Steel railway bridge fatigue damage detection using numerical models and machine learning: Mitigating influence of modeling uncertainty

Stringer-to-floor beam connections were reported as one of the most fatigue-prone details in riveted steel railway bridges. To detect stiffness degradation that results from the initiation and growth of fatigue cracks, an automated damage detection framework was proposed by the authors (Eftekhar Azam et al., 2019; Rageh et al., 2018). The proposed method relies on Proper Orthogonal Decomposition (POD) and Artificial Neural Networks (ANNs) to identify damage location and intensity under non-stationary, unknown train loads. Bridge computational models were used to simulate damage scenarios and for training the ANNs. Damage detection method efficiency and accuracy were shown to be significantly influenced by the level of modeling uncertainties (MUs). To investigate the applicability of the proposed framework to in-service bridges, a systematic analysis of the effect of MUs on the proposed POD-ANN framework was necessary. MU influence on the performance of the POD-ANN damage detection method was investigated and a new procedure for generating training data for ANNs was proposed. The procedure was based on synergizing Proper Orthogonal Modes (POMs) extracted from measured structural response and POMs calculated from the numerical model. The current study integrated numerical and field investigations. The main objective of the numerical investigation was to identify a robust damage feature independent of the level and location of assumed MUs. Results showed that Damage Location (DL) and Damage Intensity (DI) were detected with high accuracy for studied uncertainty cases; however, as expected, damage detection accuracy reduced as MU increased. A hybrid experimental-numerical approach was then implemented for the field investigation studies. This approach applied identified damage features from the numerical investigation to measurements from an in-service railway bridge to produce damage scenarios used to train the framework. MATLAB algorithms were developed that preprocessed field data and eliminated POM variations resulted from loading uncertainties. ANNs were trained and tested using the field strain estimated POMs from the hybrid approach and DL and DI results were obtained for the studied railway bridge under non-stationary, unknown train loads. These results show the promise of the POD-ANN method as a robust, real-time fatigue damage identification tool for steel railway bridges.

Investigation on fatigue crack resistance of Q370qE bridge steel at a low ambient temperature

The Q370qE steel has a wide application in the medium and long span railway steel bridges in China, due to its excellent material characteristics including high strength, high toughness and good weldability at room temperature. Nevertheless, the limited research work on the fatigue properties of the Q370qE steel challenges the safety of steel bridges in cold and severe cold regions under the cyclic actions. This study first conducts a series of strain-controlled fatigue tests of coupon specimens at room temperature and −60 °C to characterize the cyclic stress-strain curve, hysteresis loops, Masing behavior and fatigue crack initiation resistance by Coffin-Manson relationship. Thereafter, the fatigue crack propagation tests of the compact tension specimens under different stress ratios and different temperatures reveal the effect due to stress ratios and temperatures on the fatigue crack propagation resistance of the Q370qE steel through the Paris formula. Results demonstrate that the low temperatures enhance the resistance to the fatigue crack initiation and propagation of the Q370qE steel. Finally, to better quantify the performance of the Q370qE steel, this paper collects different bridge steels and compares the fatigue crack initiation resistance and fatigue crack propagation between the Q370qE steel and other bridge steels. The results quantify the excellent higher fatigue resistance of Q370qE steel in comparison with other bridge steels.

Measured properties of structural damping in railway bridges

Dissipative properties of a structural system are difficult to be characterized in real structure. Nevertheless, damping features may be dominant in several operating conditions of railway bridges influencing fatigue life or passenger comfort during train passage. Observations treating real data acquired in operational condition on steel and concrete railway bridges belonging to the Italian network permits to highlight dissipative sources and features. Consequently, linearized modal damping ratios are evaluated through a recursive process on the acceleration signals acquired before, during and after train passages and/or in environmental conditions. Stochastic Subspace Identification has been used to identify state-space dynamical models able to reproduce the vibrations. Through these models, characterized by an increasing number of state-space variables, it is possible to extract modal damping ratios. A mechanical interpretation of damping characteristics is pursued through the evaluation of the differences with respect to a classical Rayleigh proportional damping matrix of the viscous matrix belonging to the identified state-space models determined through the system spectral features. A non-proportional damping index is presented as a basis to determine the influence of different sources of non-proportionality in the damping matrix (as the ballast layer under the track) and to justify the high value of damping observed in specific experimental campaigns.