Railway Bridge Research Articles

Simulation Based Study Of Ground Mobile Robots For Inspection And Control Of The Bridge Assembly Process

Nowadays, the inspection of bridges poses a significant challenge for safeguarding critical infrastructures. Recent advancements have seen the integration of robots to replace human personnel in hazardous tasks. These robots, whether operating autonomously or through tele-operation, play a crucial role in monitoring structures and infrastructure, ensuring secure access to areas such as manholes on decks and box girder bridges. Specifically designed for environments deemed dangerous, difficult, or inaccessible to humans, ground mobile robots equipped with appropriate sensors are increasingly deployed for inspection purposes. This paper addresses simulation tests conducted by a hybrid mobile robot. Its compact design and maneuverability enable it to navigate through obstacles, making it suitable for inspecting railway or highway bridge decks as well as confined spaces within box girder bridges. The study includes a survey of existing bridges highlighting key issues to be addressed and presents simulation results for the hybrid rover, which has been developed and equipped with sensors tailored to fulfill inspection tasks within a selected case study.

IMPACT OF RURAL ROAD PROVISION ON EMPLOYMENT

This article focuses on the impact of rural road provision on the macroeconomic objective of full employment. It deals with the extent to which roads act as direct generators of jobs during their construction and service periods, and the ways in which effective roads could indirectly stimulate employment opportunities quantitatively and, from a skills perspective, qualitatively. The economic impact analysis (ECIA) of road provision indicates the typical worker–hour requirements for the approximate estimation of employment needs. These estimates can be used whenever detailed estimates are not yet available. The estimates are provided for the construction and operation of (1) basic rural road segments, (2) bridges and viaducts, and (3) intersections, roundabouts (traffic circles), and interchanges. Where road projects contain other physical components, such as tunnels and toll plazas, the former three groups of employment rates could be used in combination with worker–hour estimates for the construction and maintenance of tunnels and toll-related components.

VISIVIA research project: set-up of the VISIT (Visual Inspection for Safety-deficit Identification and Triage) methodology and use of drones for inspection of existing bridges near the road SS13 "Pontebbana".

This work illustrates the first tests of drone use in the implementation of the VISIT methodology (Visual Inspection for Safety-deficit Identification and Triage) for bridges safety surveillance purposes. Tests were organized at the University of Udine with collaborative efforts of the SPRINT-Lab researchers, ANSFISA experts and drone pilots of Italian National Fire Corps. The execution took place on three bridges near the road SS13 "Pontebbana". The research and test outcomes confirm that the activities developed with the VISIT method through the use of drones provide high inspection details without requiring traffic restrictions or the use of expensive equipment and ensuring safety conditions for road users and bridge inspectors. The test activities also focused on the need for synergistic work between bridge inspector and drone pilot, evidencing the potential of modern technologies that allow the reconstruction of highly detailed three-dimensional scenarios. The work concludes by highlighting the outcomes of the comparative test emerged during the debriefing critical discussions among all participants.

Numerical study on wind-loading characteristics of a high-speed train running over the bridge under tornado-like vortices

With global warming intensifying, weather patterns become more volatile and extremes more common. Tornadoes are the most destructive natural disasters causing significant damage to infrastructure. Meanwhile, high-speed railways now face greater risks from tornado events as the national railway network and mass transit trains expand. Thus, studying the tornado flow characteristics and associated effects on high-speed trains is necessary. A study is presented regarding the wind-loading characteristics of a high-speed train running over a railway bridge induced by a tornado belonging to the future railway network. The wind-loading characteristics analyses are performed using the improved delayed detached eddy simulation method. After verifying the numerical approach and mesh strategy, computational studies are conducted to produce a tornado-like vortex and investigate the tornado-induced wind-loading characteristics of a high-speed train running on the bridge by combining a tornado simulation with a moving mesh technique. For the wind-loading parameters studied herein, the selected train's velocity range is between 50 and 350 km/h, the typical operation speed of either regular or high-speed trains. The numerical results show that the time histories of aerodynamic forces on the train revealed a pattern in tornadic flow variability, the time evolutions of the wind loads on the train were affected by train speeds, and the fluctuation was the greatest when the train ran at 50 km/h. Moreover, the train is subjected to larger aerodynamic forces and moments when it operates along with the rotating vortex flow, especially in the core region, and the train is more dangerous when it runs at a lower speed. The results in this study provide references for assessing operation safety, while a train running on the bridge encounters tornadoes.

Mitigation strategies and measures for the protection of working railway bridges from landslides and erosion phenomena: the case study of Liguria

The Italian territory is marked by complex geology, morphology and hydrography. For this reason, hydrogeological instability is a primal issue to phenomena such as landslides, flooding and associated erosion phenomena. Within this context, the protection of existing infrastructures plays a significant role along with maintaining operational continuity and promptly restoring circulation after a forced traffic interruption. In October 2020, the railway line Cuneo-Breil-Ventimiglia was interested in a series of landslides and erosion phenomena, due to a sequence of strong meteorological events. The paper presents the study, planning, design and realization of the mitigation measures. An investigation campaign, involving both the existing structures and the geological context, al-lowed to obtain a 3D reconstruction of both the bridges and the nearby slopes, as well as the characterization of materials, the identification of high-risk areas and the design of the solution to reinforce the existing slopes and mitigate the erosion effect on bridges foundations. The software Rocscience Slide has been intensively used for the geotechnical modelling of landslides as well as to design structural works such as soil nailing. Meanwhile, the hydraulic study of the river was performed to assess the hydraulic compatibility of the riverbed construction sites.

Numerical Model Updating and Validation of a Truss Railway Bridge considering Train‐Track‐Bridge Interaction Dynamics

Numerical Model Updating and Validation of a Truss Railway Bridge considering Train‐Track‐Bridge Interaction Dynamics

Isolation and Identification of Marine Bacteria from Vaitarna Estuary, Palghar (Maharashtra) India

Microbes account for all known life forms for nearly 50 to 90% of Earth’s history. Life itself began in the ocean. Among the microbes bacteria are most vital link directly and indirectly with human life. In view of these total three sites along Vaitarna estuary namely Dativare Coast, Vaitarna Railway Bridge and Pargaon Bridge were chosen. From these area total 15 bacterial isolates were collected by standard isolation procedure and then the characterized with respect to cultural and morphological, biochemical aspects and identification by 16S rRNA sequence has been recorded.

Experimental and Numerical Investigation of Axial Load Capacity for Box-type Railway Bridges

Railway bridges are vital components of transportation infrastructure, exposed to various forces including vertical and horizontal loads. Withstanding increasing axial loads is a critical factor in railway bridge design and operation, and has been the subject of research for many years. Numerous studies have investigated the impact of axial loads on bridge behavior and developed models to forecast their response under different load conditions. This study focused on evaluating the load-carrying capacity of box-type concrete bridges, which were designed to carry a load of 21 MT, to withstand an increased axle load of 25 MT. To achieve this, Operational Modal Analysis (OMA) and finite element analysis were utilized to assess the bridges. Dynamic properties of the system were estimated by recording vibration data using wireless accelerometer sensors, while finite element analysis was developed from Visual Inspection and Non-Destructive Test (NDT) results and then paired with the OMA results. Additionally, the study estimated the maximum load-carrying capacity of the existing through numerical Analysis. To test the methodology, the study was conducted on five real-time bridges at a constant train speed of 10 Kmph. Results showed that all five bridges were capable of withstanding the increased axial load at that speed. Therefore, this study has demonstrated the effectiveness of this technique in predicting the behavior of structures under heightened dynamic loads.

Structural monitoring of a historic masonry bridge

Structural Health Monitoring (SHM) aims to develop autonomous integrated systems allowing inspection and detection of damage with minimal human intervention. It thus represents a process of implementing a damage identification strategy through which, by periodic observation of the structure, it is possible to arrive at an assessment of certain characteristics of the system, as well as to define its current state of health. The case study under consideration describes a new static and dynamic monitoring system of a five-arch masonry railway bridge, realized by a network of sensors installed according to a placement strategy. The general objective of monitoring is the acquisition of all the information concerning the current condition of the bridge and thus the structural behaviour under static and dynamic actions to ensure an adequate level of public safety. Any change in the dynamic characteristics over time is indeed an indicator of ongoing degradation in the structure, due for instance to material damage phenomena, or geometrical. The collected data are visualized in real time with the help of the Web Platform where various operating parameters including sampling rates, resolution, trigger thresholds, alarm thresholds, etc. can be set. The data are finally analysed following a scheduled plan or upon reaching pre-established alarm thresholds.

The IRRADIA research project for the advanced management of infrastructures

AISICO and ‘Sapienza’ University of Rome are working on the project IRRADIA, a research program aiming to investigate the use of Artificial Intelligence for the structural assessment of railway and road infrastructures. The starting point is the BRIGHT method (BRIdGes Health Testing method, patented by AISICO), already applied on a large data set of information, and essentially based on the automatic detection of damages on structural elements of bridges and viaducts. The results carried out on 80 railway bridges provide new ideas to the sector of monitoring and control of existing infrastructures in terms of automatization. Then, the BRIGHT method, built on the railway specifications described by DOMUS, has been recently expanded to meet the requirements of the 2022 Italian Guidelines for existing road bridges and viaducts (DM 204, 1/07/2022). These require to fulfill several defect sheets for each structural element (e.g., beams, transversal beams, slabs, piers, abutments, supports, and so on), with a proper evaluation, for each defect, of type, extension and intensity. It follows that the damage evaluation requires usually a large number of operations with a high level of repetitiveness. Therefore, the use of AI techniques is a promising tool for the near future, to acquire and collect the images with unmanned aerial vehicle, from one hand, and to fulfill the defect sheets, from the other one, reducing time and cost. In this framework, one of the main goals of the cited IRRADIA research project is the investigation of the results obtained with the BRIGHT method extended to 2022 Italian Guidelines, that is, to road infrastructures. In this contribution the first results obtained on two bridges, the first in reinforced concrete and the second with a masonry structure, are presented and discussed.

Estudo comparativo de soluções para vigas mistas empregas em obras de arte especiais ferroviárias

Abstract Steel-concrete composite bridges are a popular solution due to the structural benefits of both steel and concrete. The typical system of a concrete slab and steel I-girders for small and medium-span bridges often displays the most economical results. However, other solutions emerge as innovative alternatives for bridge construction, such as composite beams with composite dowels and pre-cambered composite beams. This paper aims to develop a comparative study of these composite beam solutions to delimitate their efficiency, performance, and economy. Thus, a case study for the superstructure of a two-way simply supported railway bridge is detailed to define the composite beam’s performance indicators. The innovative alternatives presented benefits when compared to the traditional system, demonstrating the positive impact of their use on bridges.

Refined modelling methods of structural reinforcements in the analysis of masonry bridges

Masonry arch bridges constitute a large part of today’s Italian architectural heritage. Italy has the highest percentage in Europe of masonry railway bridges with respect to the total. Due to the processes of degradation and to the increased levels of the loads and of the safety requirements, rehabilitation and retrofitting of these bridges is required. Among the available reinforcement techniques, the use of reinforcements with mortar/cement matrix fiber nets has gained great popularity due to the advantages shown over traditional techniques in terms of strength and durability. The FRCM, acronym of “Fiber Reinforced Cementitious Matrix” is a valid reinforcement alternative to the use of polymeric matrix reinforcements, due to its greater compatibility with the masonry support. The Italian technical standards suggest a simplified method for the design of the reinforcement based on empirical coefficients that increase the mechanical properties of the masonry materials, disregarding the consideration of the complex crisis mechanisms occurring, especially in more complex systems like the multi-arch bridges.The object of this work is the definition of a more refined and efficient method for the numerical modeling of FRCM reinforcement in the structural analysis of multi-span masonry arch bridge. Specifically, an equivalent reduced nets embedded in a mortar continuum determined with the area equivalence principle.The model is calibrated based on experimental characterization tests carried out on PBO-Mesh, and on the constituents. A validation test of the model is performed with reference to arch models reinforced with PBO-Mesh experimentally tested.The effectiveness of the proposed approaches is verified analyzing the seismic behavior of a masonry multi-span bridge, also considering the soil-structure interaction.

Time domain analysis of catenary response characteristics caused by ambient wind

Abstract The catenary system, as a framework within railway electrification projects, constitutes an exposed suspension structure deployed along railway lines. It serves the purpose of providing electrical power to electric locomotives through pantographs but lacks backup facilities and falls into the category of a specialized form of high-voltage transmission line. To ensure the safety and reliability of the catenary system and the stable current collection of the pantograph, thereby safeguarding railway operational safety, it is imperative to research the aerodynamic response of the catenary system induced by environmental winds. For this study, the catenary system in the 4m windbreak wall section of the Lanzhou-Xinjiang high-speed railway bridge has been selected as the research subject. To determine wind speed correction coefficients at the supporting cable and contact wire locations, a finite element model was created using wind tunnel experiments and numerical simulations. Samples of wind speed fluctuation have been obtained using the harmonic synthesis method. Based on quasi-steady aerodynamic theory, a temporal analysis has been conducted on the aerodynamic response of supporting cables and contact wires under the influence of both average and fluctuating winds. Temporal results, such as lift at positive and negative positioning locations and mid-span displacement, have been extracted to assess whether the existing structure complies with regulatory requirements. This study offers valuable insights for engineering applications that are similar.

Assessing the surface corrosion of a steel railway bridge using an active short-range remote sensing system

Assessing the surface corrosion of a steel railway bridge using an active short-range remote sensing system

Impact Assessment of Railway Bridge Construction Schedule, based on 3D Geotechnical Finite Element Modeling

Impact Assessment of Railway Bridge Construction Schedule, based on 3D Geotechnical Finite Element Modeling

Research on the impact of underground box culvert underpass construction on the pier of intercity railroad bridge

Research on the impact of underground box culvert underpass construction on the pier of intercity railroad bridge

Road bridges exposure and alternative routes: towards the definition of road network resilience

The road network represents both element-at-risk and key infrastructure to ensure the accessibility of peripheral areas. The overall risk levels of bridges depend on geophysical (mainly earthquakes and landslides) and hydrometeorological hazards (mainly floods), the physical vulnerability of structures, and the exposure (mainly resulting from traffic flows and the presence of alternative roads). In mountain contexts and peripheral territories, the accessibility of entire territorial system directly depends on few trunk and secondary roads. The risk assessment of bridges, according to the Ministerial Guidelines, provides inputs for a territorial risk assessment starting from the accessibility of peripheral territories and the redundancy of the road network as features to determine the resilience of the road network. This study aims at understanding the relationships between bridges as elements-at-risk part of the road network and the influence they have on the overall accessibility of a territory. In this study, through a GIS analysis of a set of selected roads of the Provinces of Caserta (Campania Region), the presence of bridges along the selected roads have been combined with data on the accessibility levels of municipalities they connect. At this purpose, reference to the classification provided by the National Strategy for Inner Areas (SNAI) has been made to understand how such a classification can change due to a road interruption because of a bridge interruption. The contribution aims at setting the stage for the implementation of a method to determine the presence of alternative roads based on travel times adopted by the SNAI classification and, as a result, the definition of unique threshold values that justifies the variation of the exposure class and allows to determine the resilience of the whole road network.

A methodology for the preliminary seismic assessment of road bridges within the italian guidelines on the assessment and management of risk conditions of bridges

Following the tragic collapse of the Polcevera Bridge in Genova (Italy), the Italian Ministry of Sustainable Infrastructure and Mobility issued the guidelines for “risk classification and management, safety assessment and monitoring of existing bridges”. This guideline proposes a multi-level procedure with an increasing level of information to be collected in each step. In this context, the MLAZIO project was born with the aim to create a methodology for the construction of an efficient Bridge Management System (BMS) for Lazio Region that takes in account all the levels prescribed in the Italian guidelines. Satellite monitoring, BIM, GIS and methods for risk assessment, both static and seismic, are some of the innovative techniques included in the methodology, validated through the application to several case studies. This paper describes the general structure of MLAZIO project and its state of progress, such as the creation of a relational database (used for cataloging structures and developing optimized GIS and BIM environments), with a special focus on the development of an expeditious procedure for the quantitative evaluation of the static and seismic risk of bridges. In this regard, a specific application has been developed that allows to automatically assess the static and seismic risk index of a bridge starting from the limited information included in the database.

Statistical analysis of existing bridges inspection results and road network risk management

The Italian scenario of road bridges appears particularly singular as most of the road bridges were built around the early ‘70s of the last century. This paper focuses on the peculiar situations encountered during the inspection activities carried out by the National Safety Agency for Safety of Railway and Road infrastructures (Ansfisa). In particular, an analytical picture of the inspection experience conducted by Ansfisa on the A24 and A25 autoroutes is presented. The infrastructure sample analyzed concerns of 549 existing bridges. The performed inspections allowed for obtaining data on the state of conservation of the considered structures. The statistical elaboration of the collected data, allowed for highlighting typical situations of the state of conservations of typical Italian highway bridges, as well as for drawing considerations useful for the planning of random inspection activities and for the management of infrastructural risk at the network.

Interoperability between structural and geotechnical analysis for the study of safety in existing bridges

In recent years, the engineering community has shown a significant increase in interest in the field of soil-structure interaction. This problem is undoubtedly one of the most complex. Despite the exponential increase in computer performance in the last two decades, followed by the continuous development of numerical methods, the interaction between structural analysis programs and geotechnical issues remains limited. Specialized calculation codes for structural engineering and geotechnical engineering often operate independently. The reason for this separation lies in the highly specialized capabilities that a solver designed for geotechnical issues must possess. However, it remains crucial to incorporate the structural element within its geotechnical context, especially in the case of structures that are fully or partially embedded in the ground, such as tunnels, retaining walls, bridge abutments, and so on. There exists a mutual and reciprocal influence of the stress-strain state: the stiffness (and strength) of the foundation determines the response of the structure, which in turn affects the response of the foundation through its own stiffness. In many projects, there is an increasing demand to develop analyses that harness the full potential of both the structural and geotechnical aspects. Hence, there is a clear need to establish a connection between these two computational environments. The proposed solution involves the interaction of two programs: Midas Civil, an essential tool for structural engineers, and Flac 3D, a general-purpose software for geotechnical engineering. As explained further, this interaction is made possible thanks to the flexibility and openness of both software codes. Referring to a real case study of a road bridge with a superstructure consisting of reinforced concrete beams, this paper will illustrate the main challenges, significant steps, and undeniable advantages obtained through this approach.