Riveted Steel Bridges Research Articles

Upgrading the load carrying capacity of old riveted steel bridge – Case study

Upgrading the load carrying capacity of old riveted steel bridge – Case study

Structural Integrity – Historical developments through millennia

In this contribution, historical aspects through millennia of structural integrity development are presented, starting from the Great Pyramids in antient Egypt. Special attention is paid to the history of bridges, made of wood and stone in antient and medieval time, then from different kinds of iron and steel following the first Industrial revolution and finally by concrete, be it reinforced or pre-stresses, in modern times. The focus of this contribution is on bridges restoration, reconstruction and preservation as part of the world heritage. Two case studies are described, the old stone bridge in Mostar (Bosnia and Herzegovina) and a historical iron bridge in Transylvania (Romania). In the second case structural integrity analysis was performed in the form of Engineering Critical Assessment, to provide a solution for retrofitting the historical riveted steel bridge. This paper is dedicated to the memory of Prof. Stojan Sedmak (1929-2014), one of the fathers of the fracture mechanics in Southeast Europe. Motivation for our research is the paper published 12 years ago on the significance and applicability of structural integrity assessment, Sedmak et al (2012), which was based on the presentation at the Tenth Meeting “New Trends in Fatigue and Fracture” (NT2F10) in Metz, France, 2010.

Sustainable system with non-intrusive anchors for the preservation of historic steel structures

This study introduces an innovative, non-invasive anchorage system for preserving historic steel structures, such as riveted bridges, which are valuable heritage assets requiring maintenance that does not compromise their structural integrity. Overcoming the accessibility and limitations of traditional methods, the proposed system employs clamp-based connections, allowing for removable anchoring without invasive interventions like welding or drilling. We demonstrate the applicability and efficacy of this system through Finite Element Model (FEM) simulations and laboratory experiments, validating its load-bearing capacity necessary for maintenance and inspection. Installing these elements on riveted steel bridges highlights the practical application of the developed technology, underscoring its potential for the sustainable maintenance of historic steel structures without compromising their integrity or historical value.

Safety assessment and retrofitting of a historic double deck riveted steel bridge

The problem of managing existing bridges on the national territory is now extremely topical, considering that most of these works have exceeded their design life and that traffic on its roads and rail networks has increased significantly over the years, both in terms of flow and load intensity. The case study, it is a double deck riveted steel bridge, the lower one dedicated to railroad traffic and higher one to road traffic, dating back to two different eras since the masonry substructures were built towards the end of the 19th century, while the steel truss was replaced after the Second World War. It consists of a single steel truss structure with three spans, two of which have lateral span of 82.40 m and central one of 99.00 m, for a total length of 263.80 m. The study aims to evaluate and ensure the safety of the work in accordance with current code (NTC2018-RFI Manual) by introducing reinforcement systems on the steel truss bridge that increase its strength while preserving its original architectural appearance. The static and dynamic structural analyses were carried out by defining a finite element model (FEM), within which different load conditions and positions between the railway and road deck were implemented, assessing their contemporaneity, in order to maximize the stresses. The reliability of the implemented numerical model was demonstrated by a calibration process, following specific load tests, with displacements reasonably comparable with the experimental results. The safety level of both the existing conditions and the project has been defined through the implementation of VBA scripts and automated spreadsheets, made on an ad hoc basis, which allow the development of all the checks on the structural elements of non-standard sections, i. e. composite riveted sections. In assessing the safety index, it was taken into account the state of conservation of the structure and of the transitional stages in the implementation of the reinforcement systems.

Gaussian Copula-based Bayesian network approach for characterizing spatial variability in aging steel bridges

Finite Element (FE) modeling often requires unavoidable simplifications or assumptions due to a lack of experimental data, modeling complexity, or non-affordable computational cost. One such simplification is modeling corrosion phenomena or material properties, which are usually assumed to be uniform throughout the structure. However, e.g., corrosion has a local nature and severe consequences on the behavior of steel structures that should not be overlooked. To improve the current numerical modeling techniques in aging steel bridges, this paper proposes a Gaussian Copula-based Bayesian Network (GCBN) approach to model the spatial variability of structural element properties. Accordingly, a study of the automatic Bayesian network generation process is first conducted. Subsequently, the methodology is applied to a severely damaged riveted steel bridge built in 1897. The results show that the methodology has excellent flexibility for generating properties variability in FE models at a low computational cost, thus ensuring its practical feasibility and robustness for accurate numerical modeling.

Deterministic and probabilistic-based model updating of aging steel bridges

Numerical modeling is a very useful tool in different fields of bridge engineering, such as load-carrying capacity assessment or structural health monitoring. Developing a reliable computational model that accurately represents the actual bridge mechanical behavior entails advanced FEM-based modeling complemented by a comprehensive experimental campaign that provides the necessary supporting information and allows validating simulation outcomes. This paper proposes a unified approach aimed at the experimental characterization and FE model updating of aging steel bridges. It first involves the realization of an extensive experimental campaign aimed at the bridge's geometrical, material, and dynamic behavior characterization. Then, a model calibration framework is developed, where deterministic (optimization) and probabilistic (Bayesian inference) approaches are employed, and techniques such as global variance-based sensitivity analysis and Kriging-based surrogate modeling are further implemented in order to enhance the identification process and reduce the overall computational burden. The methodology has been validated in a historical riveted steel bridge in O Barqueiro, north of Galicia, Spain. The results show a good agreement in the identified model parameter values and a noticeable correlation between numerical and experimental modal properties, with an average relative error in frequencies of 0.34% and 0.44% for the deterministic and probabilistic approaches and an average MAC (Modal Assurance Criterion) ratio of 0.96.

Structural health control of historical steel structures using HBIM

In architecture and civil engineering, maintaining historical constructions is essential for preserving cultural heritage. This is especially relevant in constructions exposed to a high degree of degradation, such as historic steel structures. The HBIM (Heritage Building Information Modeling) technology can facilitate and automate this task. In this paper, a methodology based on an HBIM framework is proposed and applied, which allows the control and monitoring of structural health over time. On the one hand, an architectural model of the construction is created. This model collects, in detail, aspects such as the geometrical shape, material composition, structural configuration, and additional data required for the control and management of the construction. On the other hand, a calibrated structural model is also automatically generated. This model represents the actual overall mechanical behavior of the construction. Both models are seamlessly integrated, evolve, and collect data of all the different control or maintenance phases of the construction. The methodology has been validated in the case study of the riveted steel bridge of O Barqueiro, located in Galicia, Spain.

A unified evaluation method for fatigue resistance of riveted joints based on structural stress approach

Many riveted steel bridges were constructed worldwide between 1850 and 1950. A number of them are still in operation, and their fatigue damage is a major burden in maintenance. This paper presents a unified structural stress approach to evaluate the fatigue resistance of riveted joints for steel bridges. The presented approach was utilized to establish and calibrate S-N curves for riveted joints based on fatigue data from 114 tested specimens, and the curves were validated by fatigue test data from large-scale riveted structures. A single fatigue category was obtained to evaluate different types and sizes of riveted structures. The investigation results showed that the presented approach is capable of evaluating different types of riveted joints and structural stresses. The structural stress approach is insensitive to the mesh size and the element type in finite element analysis. The presented method is convenient for practical engineers to evaluate the fatigue resistance and fatigue life of riveted steel bridges.

Residual life of a historic riveted steel bridge - engineering critical assessment approach

Sustainability has become an increasingly important component of requirements for the rehabilitation of bridge structures. Responsible use of our limited natural resources is essential for future generations, so the whole bridge rehabilitation process must be taken into account, in terms of structural integrity. The environmental impact for these types of structures is major – demolition and reconsideration of e.g. reinforced concrete structure being examples of poor management of resources and energy. On the existing roads and railways network steel bridges with more than 100 years in service lifetime are numerous. The in-service safety assessment of these structures is a complex problem. This article emphasizes the importance of rehabilitating the structure of existing steel bridges, considering the historical monument character of these structures, as well as the reuse of existing structures, part of sustainable development. The paper is presenting a study case for an historical riveted steel bridge build in the beginning of twentieth century, with an assessment method considering the structural integrity by means of fracture mechanics.

Distributed Fiber Optic Sensor-Based Strain Monitoring of a Riveted Bridge Joint Under Fatigue Loading

Riveted steel bridges, which were built in the early 20th century, require their regular structural integrity assessment to avoid any catastrophic failure. This article presents continuous strain monitoring of a single riveted lap joint, which is a representative critical element of riveted steel bridges through an optical frequency domain reflectometry (OFDR)-based distributed fiber optic sensor (DFOS). The aim of this study was to instrument a DFOS on a single riveted lap joint for monitoring the surface and critical strains experienced by the rivet joint under two fatigue loading conditions and also to compare the strain transfer between the two commonly used adhesives for bonding the DFOS. Initially, through finite element analysis (FEA), a location for installing the DFOS was identified, and also a strategy was developed for monitoring the critical location of the joint during fatigue loading. Subsequently, the DFOS was instrumented on the riveted joint at the identified location in two segments, where similar strain levels were expected with the aid of two types of adhesives: cyanoacrylate and epoxy. The strains on the rivet joint were monitored under high cycle fatigue (HCF) for up to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2\times {10}^{6}$ </tex-math></inline-formula> loading cycles with constant stress amplitude and followed by low cycle fatigue (LCF) loading with increasing stress amplitude until the failure of the specimen. The results showed that the DFOS could continuously sense the cyclic peak strain of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$- 223\,\,\mu \varepsilon $ </tex-math></inline-formula> under HCF conditions and a peak maximum strain of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$- 1244\,\,\mu \varepsilon $ </tex-math></inline-formula> under LCF conditions. Furthermore, the internal critical strain on the rivet joint during loading could be monitored with the application of the developed damage monitoring strategy and DFOS strain data. Finally, the DFOS segment bonded using cyanoacrylate measured marginally high strains than epoxy adhesive during the HCF test.

Robustness of steel truss bridges: Laboratory testing of a full-scale 21-metre bridge span

This study aimed to experimentally analyse the robustness of riveted steel bridges based on truss-type structures and to define practical recommendations for early detection of local failures before they cause progressive structural collapse. Although there are many experimental studies on robustness and progressive collapse on buildings, those on bridges are either theoretical or deal with actual collapses. This paper describes a unique case of a 21 m full-scale bridge span tested under laboratory conditions with an extensive monitoring system, together with an experimental study to evaluate structural behaviour and robustness as damage or failure progressed in its elements. A linear-static finite-element analysis was also included to examine other possible causes not included in the experiment. The results proved the structural redundancy of this type of truss structure based on the joints’ resistance to bending moments and gave rise to a series of practical structural health recommendations to identify early failures and avoid progressive or sudden bridge collapse. The study carried out and the recommendations it produced are now being applied in three similar bridge case studies.

Field-testing and numerical simulation of vantage steel bridge

Several steel bridges in Egypt were built during the late nineteenth to early twentieth centuries. At this time, riveted construction was the method used for building up members and for the connection of one member to another. In this paper, field measurements were performed to find the actual dimension of an existing old riveted steel bridge (El-Ministerly Bridge, Egypt). The inspection of the steel bridge did not find any clear cracks. Finite element models were created to predict the response of the steel bridge. The finite element model was used to identify the location of the stress concentration. A static field test was performed using a 49-ton truck to evaluate actual strain measurements in different locations over the bridge. The strain measurement was used to validate the finite element model while was able to predict the experimental data closely. As an application of the use of the finite element model, evaluate the bridge was executed using AASHTO standards, Egyptian code (ECP) and S–N curves from the literature. It was observed that all stress ranges for this bridge were less than the ECP limits (Fsr) and the estimated remaining fatigue life is about 11 years if it is environmentally protected.

Fatigue crack growth modelling of Fão Bridge puddle iron under variable amplitude loading

This study addresses the fatigue crack growth behaviour of a material from an old riveted steel bridge, the Portuguese Fão Bridge, based on an experimental program of constant and variable amplitude loading tests. The material under consideration is a centenary puddle iron, for which information on fatigue crack growth under variable amplitude loads is not available in the literature. Additionally, the experimental program aimed at analysing the fracture surfaces of the specimens through observations under Scanning Electron Microscopy (SEM), and correlate their characteristics with macroscopic fatigue crack growth behaviour. Furthermore, a crack closure analysis was performed using electrical strain gauges applied on the back face of the CT specimens. The fatigue crack propagation along the parallel to the rolling direction (L) revealed to be higher when compared with the transverse direction (T). The experimental data obtained in this study were compared with existing fatigue crack propagation models, such as the Paris model with linear damage accumulation, according to Miner’s rule, as well as with more complex crack propagation models, with capacity for modelling retardation effects of single overloads. The Paris model with linear damage accumulation, despite its simplicity, led to the best predictions for the generality of variable amplitude random block loading. The original Wheeler model is enough to correlate the crack propagation data under overloads, since the application of more sophisticated models would not be justified by the extremely high scatter observed in these old materials.

Fatigue of Preloaded Bolted Connections with Injection Bolts

Injection bolts have been used to replace faulty rivets on strengthening operations of old riveted steel bridges. This technology has been essentially tested for its quasi-static or creep behaviour and there are very few studies concerned the assessment of its fatigue resistance. This paper presents an experimental program developed to evaluate the fatigue behaviour of single shear preloaded bolted connections with injection and standard bolts. Specimens combine S355 steel and old metallic material obtained from structural elements of the centenary Eiffel bridge in Portugal. Fatigue failure was found either at the net cross-section or at a gross cross-section of the plates. Statistical analysis was conducted on the experimental data to compare with the fatigue design curves proposed in Eurocode 3, part 1-9. It is concluded that the detail category suggested on the reference code is not able to represent the fatigue life of old steel materials. An alternative S-N curve is proposed which is able to represent the fatigue behaviour of the studied detail. Furthermore, it was concluded that the influence of the adhesive on the detail’s fatigue strength is not significant.

Fatigue Performance Evaluation and Cold Reinforcement for Old Steel Bridges

Fatigue and corrosion damage in existing old steel bridges are accumulated continuously in service stage, probably leading to structural failure. One old welded steel bridge and one old riveted steel bridge are taken as examples for structural performance and safety evaluation. A large number of out plan deformation-induced long fatigue cracks were found at the connection plates connecting the bottom flange of end cross-frames and main girders of the two old steel bridges, and serious corrosion damage was found at such details of the old riveted steel bridge. Cold reinforcement techniques of drilling stop holes and bonding and bolting steel plates were adopted to strengthen the old steel bridges. Fracture mechanical models using the short-term monitoring data were established to assess the fatigue lives before and after the reinforcement, considering the coupling effect of fatigue and corrosion, and the evaluation results indicate that corrosion and fatigue coupling is very significant for old steel bridges. Monitoring and evaluation results show that bonding and bolting steel plates leads to about 90% reduction in the maximum tensile stress and about 8 times fatigue lives extension, while drilling stop holes can only temporarily arrest the crack growth. Additionally, the future maintenance strategies recommendations are provided.

Fatigue characterization of a beam-to-column riveted joint

Fatigue failures are a concern for old riveted steel bridges since most of them were not originally designed taking into account fatigue. The usual fatigue assessment approach for riveted joints consists of using the fatigue class 71 S-N curve proposed in Eurocode 3, part 1–9. However, this approach may lead to excessive conservative predictions since it is applied indistinctly for different riveted connection geometries and materials. Riveted joints fatigue classification according to the proposal of Taras and Greiner produce more consistent description of the experimental data rather than the Class 71 S-N curve as proposed in the EC3. Local approaches are an alternative methodology to perform fatigue characterization of any type of joints, made of any material, providing that material fatigue properties are available as well as accurate numerical models of the joints. This paper presents an experimental campaign and a numerical analysis concerning down-scale riveted specimens. The fatigue behaviour of these riveted joints was also modelled using standard and extended finite element methods. The different models produced diverse predictions, depending on the failure modes considered.

Getting More Out of Existing Structures: Steel Bridge Strengthening via UHPFRC

Ultra High Performance Fiber Reinforced Cement-based Composite (UHPFRC) has been increasingly adopted for rehabilitation projects over the past two decades, proving itself as a reliable, cost efficient and sustainable alternative against conventional methods. High compressive strength, low permeability and high ductility are some of the characteristics that render UHPFRC an excellent material for repairing existing aged infrastructure. UHPFRC is most commonly applied as a surface layer for strengthening and rehabilitation of concrete structures, such as bridge decks or building slabs. However, hitherto its implementation with steel structures has so far been limited. In this work, the UHPFRC strengthening of a steel bridge is investigated both in simulation as well as in the laboratory, by exploiting a real-world case study: the Buna Bridge. This Croatian riveted steel bridge, constructed in 1893, repaired in 1953, and decommissioned since 2010, was removed from its original location and transported to laboratory facilities for testing prior to and after rehabilitation via addition of UHPFRC slab. The testing campaign includes static and dynamic experiments featuring state-of-the-art monitoring systems such as embedded fiber optics, acoustic emission sensors and digital image correlation. The information obtained prior to rehabilitation serves for characterization of the actual condition of the structure and allows the design of the rehabilitation solution. The UHPFRC slab thickness was optimized to deliver optimal fatigue and ultimate capacity improvement at reasonable cost. Once the design was implemented, a second round of experiments was conducted in order to confirm the validity of the solution, with particular attention allocated on the interface between the steel substrate and the UHPFRC overlay, as the connection between both materials may result on a weak contact point. A detailed fatigue analysis, based on updated FEM models prior to and after strengthening, combined with the results of a reliability analysis prove the benefits of adoption of such a solution via the significant extension of the structural lifespan.

A comparison between S-N Logistic and Kohout-Věchet formulations applied to the fatigue data of old metallic bridges materials

A new formulation of a Logistic deterministic S-N curve is applied to fatigue data of metallic materials from ancient Portuguese riveted steel bridges. This formulation is based on a modified logistic relation that uses three parameters to fit the low-cycle- (LCF), finite-life- and high-cycle-fatigue (HCF) regions. This model is compared to the Kohout-Věchet fatigue model, which has a refined adjustment from very low-cycle fatigue (VLCF) to very high-cycle fatigue (VHCF). These models are also compared with other models, such as, Power law and fatigue-life curve from the ASTM E739 standard. The modelling performance of the S-N curves was made using the fatigue data considering the stress fatigue damage parameter for the materials from the Eiffel, Luiz I, Fao and Trezoi riveted steel bridges. Using a qualitative methodology of graphical adjustment analysis and another quantitative using the mean square error, it was possible to evaluate the performance of the mean S-N curve formulation. The results showed that the formulation of the S-N curve using the Logistic equation applied to the metallic materials from the old bridges obtained superior performance to the analysed models, both in the estimation of fatigue behaviour in the low-cycle fatigue (LCF) region and in the lowest mean square error.

Crack-Detection in old riveted steel bridge structures

In light of the scarcity of resources, the fundamental demand for economic and sustainable use of existing structures is becoming increasingly important. A large number of existing steel bridges fulfill their purpose in principle. But almost 30% of steel railway bridges in Germany are up to 100 years old. Considering deterioration as well as significantly increased loads, however, they must meet the current requirements of stability and fatigue resistance. Of fundamental importance is the realistic assessment of the state of fatigue of the steel bridge structures.If no sufficient remaining fatigue life can be determined based on normative S-N-curve assessment, initiation of fatigue cracks has to be assumed. Steel bridges from the period 1880 to 1940 are usually riveted steel structures. Therefore, crack initiation occurs primarily at the edge of the rivet holes. In this early phase of crack growth, however, a crack at the rivet hole is still below the rivet head and therefore cannot be found in a visual inspection of the structure. For this reason, the remaining cyclic lifetime based on fracture mechanics is determined assuming a start length of the crack beyond the rivet head.Currently, there is no practicable non-destructive testing method to detect hidden cracks in riveted joints. X-ray inspection requires complex precautions for occupational safety. Ultrasonic tests are also very expensive, since each rivet would have to be examined separately. This paper describes investigations using Lock-In-Thermography for crack detection in riveted joints.

MECHANICAL CHARACTERIZATION OF ANCIENT PORTUGUESE RIVETED BRIDGES STEELS

In repairing and retrofitting processes of ancient riveted steel bridges is crucial to assess the structural state of old metals to guaranty structural safety. Metals under long-time operations (mild, rimmed low carbon steels &amp;lt;0.1% C, puddle irons) and cyclic loading present a tendency for degradation processes. The case-studies of this work are five metallic bridges existing in Portugal (Luiz I, Eiffel, Fao, Pinhao and Trezoi). This work presents the study of some characteristics of materials extracted from the five case-studies, such as: monotonic tensile strength, chemical composition, microstructures, hardness, notch toughness and fatigue crack propagation. In terms of monotonic tensile tests, the materials from Luiz I, Eiffel and Fao bridges are similar to puddle steel and the materials from Pinhao and Trezoi bridges are similar to mild steel. In terms of toughness only the material from the Pinhao bridge exhibits acceptable toughness properties, considering current design requirements. The materials from the other bridges exhibit relatively low toughness properties. The fatigue crack propagation data from the old Portuguese riveted steel bridges were correlated using the Paris’s law and the possibility for a design crack growth rate was discussed.