Rail Bridge Research Articles

Lateral girder displacement effect on the safety and comfortability of the high-speed rail train operation

Rail irregularity presents a major threat to the high-speed train (HST) safety on a high-speed rail (HSR) bridge. Lateral bridge deformation has a significant impact on geometric parameters of the rail. In this paper, the influence of lateral bridge deformation on the train operation on the HSR bridge is investigated. Variational calculus is employed to establish the analytical mapping between the lateral bridge and rail deformation. By superimposing the mapped rail deformation and initial random rail irregularity, the composed rail unevenness under lateral bridge deformation is obtained. Thereafter, by adopting the dynamical model of the train-track-bridge coupling system (TTBCS), the dynamic behaviour of the train moving across the HSR track-bridge system is analysed. Based on safety and comfortability control indicators of the HST operation, effects of different types of lateral bridge deformations with various amplitudes on the train’s operation performances are investigated. The results indicate that the bilateral girder’s mutual translation has the most significant impact on the train’s operation. When the HST is moving with the velocity of 350 km/h, lateral bridge deformation amplitude thresholds are suggested as 17.43 and 8.12 mm to ensure the safety and comfortability of the HST operation, respectively. The obtained results can provide beneficial pointers for HSR bridge design.

Application of BIM modeling technology in Bridge Engineering

BIM (building information modeling) is a new engineering technology which appears at the beginning of this century. It takes the relevant information data of the project as the model basis, establishes the building model, and simulates the real information of the project through the digital information simulation technology. In recent years, China’s BIM Technology has gradually extended from the construction industry to the transportation industry, and has achieved good application in rail transit, bridge design and other aspects.

Thermal Analysis of Heat Distribution in Busbars during Rated Current Flow in Low-Voltage Industrial Switchgear

The manuscript presents advanced coupled analysis: Maxwell 3D, Transient Thermal and Fluent CFD, at the time of a rated current occurring on the main busbars in the low-voltage switchgear. The simulations were procured in order to aid the design process of such enclosures. The analysis presented the rated current flow in the switchgear busbars, which allowed determining their temperature values. The main assumption of the simulation was measurements of temperature rise during rated current conditions. Simulating such conditions is a valuable asset in order to design better solutions for energy distribution gear. The simulation model was a precise representation of the actual prototype of the switchgear. Simulations results were validated by experimental research. The heat dissipation in busbars and switchgear housing through air convection was presented. The temperature distribution for the insulators in the rail bridge made of fireproof material was considered: halogen-free polyester. The results obtained during the simulation allowed for a detailed analysis of switchgear design and proper conclusions in practical and theoretical aspects. That helped in introducing structural changes in the prepared prototype of the switchgear at the design and construction stages. Deep analysis of the simulation results allowed for the development concerning the final prototype of the switchgear, which could be subjected to the full type tests. Additionally, short-circuit current simulations were procured and presented.

Criticality assessment for a regional maritime economy.

To identify and assess the criticality for infrastructure assets and better understand their dependencies, interdependencies, and supply chain reliance. This study used a modified mission impact, symbolism, history, accessibility, recognizability, population, and proximity model combined with a deliberative process with regional subject matter experts. Hampton roads Virginia maritime area. Emergency managers, US Corps of Engineers, US Coast Guard, law enforcement, railroad industry, intelligence community, Virginia Department of Emergency Management, Virginia Department of Transportation, and Virginia Port. A prioritized list of one-to-n critical assets in the maritime area and identification of up and down-stream dependencies. The final most highly critical grouping included 26 out of 277 assets including especially important road bridges and tunnels, rail bridges and choke points, shipping channels, and marine terminals. Subject matter experts identified 277 critical infrastructure assets in the Hampton Roads Maritime Area (HRMA). From these, 26 assets that were deemed to be significantly more critical than others. From this reduced list, 12 were further assessed to be most important. The selection process provided significant support to those responsible for providing protection, mitigating potential damage, and planning recovery and allows informed, objective expenditures of limited funding. Additional key findings include the following: Proximity, or the potential for an asset that has been damaged or destroyed to cause direct harm to adjacent assets in the surrounding community, drives criticality in the HRMA more than any other factor in the model. A small group of 26 out of 277 assets exerts an outsized impact in the HRMA-nearly 20 percent of criticality-due to the potential consequences associated with their destruction or disruption. Road transportation, particularly tunnels, represents the primary dependency among critical assets. Major road and maritime transportation assets rely heavily on federal and state organizations to maintain their function. Supply chain: The critical asset group supports or supplies many missions and industries both nationally and internationally, including defense, manufacturing, commercial enterprise, and the movement of raw commodities.

Complementarity of island cross-sea transport links: Bridges, ferries, and mobility in Zhoushan Archipelago, China

Islands and archipelagos are exceptionally dependent on the nature of their transport infrastructure, with cross-sea transport links being of fundamental importance for mobility. Traditionally, the island geography research literature has engaged in a binary and oppositional understanding of the relationship between fixed links such as bridges and tunnels on the one hand and waterborne transport such as ferries on the other. The present paper uses the case of Zhoushan Archipelago (Zhejiang Province, China) to challenge this perception of fixed links and waterborne transport as inherently conflictual by showing how these distinct modes of cross-sea transport have complemented one another and fundamentally altered archipelagic mobilities. We show that even transformative transport infrastructures do not necessarily simply replace existing infrastructures but may instead add to the complexity of the local transport network. In Zhoushan Archipelago, a vast network of new and future inter-island and island-mainland road and rail bridges and tunnels are altering local industry and society as well as the relationship between the archipelago and the mainland, yet ferries remain important for transport between islands and between certain islands and the mainland. We argue that it is fruitful to consider the potential complementarity of different kinds of cross-sea transport links.

An Efficient Non-Iterative Hybrid Method for Analyzing Train–Rail–Bridge Interaction Problems

The dynamic interaction problem for the train–rail–bridge (TRB) systems presents a computational challenge, especially for the analysis of large-size TRB coupling systems. To address this issue, an efficient non-iterative hybrid method (NHM) is proposed. With this method, the integrated TRB system is divided into three subsystems, i.e. the train subsystem, the rail subsystem, and the bridge subsystem. Based on the individual subsystems, a multi-step[Formula: see text] technique is adopted in which a fine time step is used to analyze the high-frequency coupling vibration for the train and rail subsystems, and a coarse time step is adopted to calculate the low-frequency coupling vibration for the rail and bridge subsystem. Additionally, Zhais explicit integral method is used to predict the displacement of the wheelsets and the rail at the current time step before using the Newmark method. The proposed method incorporates the advantages of Zhai’s explicit method and the MS technique to avoid the iteration that may be required for the train–rail coupled analysis. The simulation fidelity and computational efficiency of the proposed method are demonstrated in the analysis of two examples of typical high-speed railway bridges. It was demonstrated that the proposed method can significantly enhance the computational efficiency, while maintaining a higher precision with a larger time step in comparison with other existing methods.

The Specificity of Dynamic Resistance of Existing Bridge Structures in Mining Areas

The article presents the results of a dynamic resistance analysis of selected existing bridge structures. The numerical calculations performed with the use of THA (time history analysis) pertained to road and rail bridges of steel and concrete structures—not paraseismically designed. The purpose of the work was to determine the dynamic resistance of objects to the influence of paraseismic impacts resulting from mining operations. The specificity of performing calculations in this area of engineering issues is presented. Real mining tremor signals, registered in the vicinity of the objects were used in the numerical analyses. The correct determination of the dynamic resistance of the object can be used as a basis for performing repair/strengthening of existing objects, which in the future will be loaded with additional paraseismic influences.

Prediction of Crosswind-Induced Derailment of Train–Rail–Bridge System by Vector Mechanics

AbstractA train–rail–bridge (TRB) interaction model of vector mechanics (VM) is developed to predict the derailment of a train traveling over cable-supported bridges under crosswinds. The aerodynam...

Load effects and associated forces for bridges subjected to light rail transit

This paper presents a numerical study concerning light rail (LR) bridges, with emphasis on the characterisation of load effects and the interaction between LR loadings and supporting structures. The predicted bridge responses were employed to appraise the provisions of the Association of State Highway and Transportation Officials (Aashto) load and resistance factor design (LRFD) bridge design specifications (BDS) and the American Railway Engineering and Maintenance-of-Way Association manual. Because existing methods to determine live load distributions and skew correction factors are inadequate for LR bridges, new design equations are proposed. A single multiple presence factor of 1·0 is recommended for LR bridges, regardless of loaded tracks. The centrifugal force of curved bridges decays as the radius of curvature increases due to a change in centrifugal acceleration. Regarding the longitudinal force resulting from train braking, multipliers are suggested for design provisions. Temperature-induced loading is distributed to the bridge girders. Rail break is expected up to 75 mm within the range of thermal loading specified in Aashto LRFD BDS, which leads to an increase in dynamic load allowance. The force transfer from superstructure to substructure is marginally influenced by bearing arrangement. A statistical test was conducted to comparatively assess the equivalency of the bridge responses related to the above-mentioned design parameters.

Mapping relation between pier settlement and rail deformation of unit slab track system

In order to study the effect of the vertical deformation of continuous beam structure of CRTS Ι slab ballastless track on rail deformation, this paper analyzes the mapping mechanism of the structural vertical deformation-rail deformation. Based on the principle of stationary potential energy, the work derives an analytical expression for a mapping between the vertical deformation of continuous beam structure and rail deformation by considering the effect of the subgrade. Then, the mapping relation between the vertical deformation of various typical bridge structures and rail deformation was calculated using analytical method. The results were compared with those obtained using ANSYS finite element method. The effects of four factors on rail deformation were investigated, namely, pier settlement, staggered steps on girder, rotation angles on beam ends, and number of spans of simply supported beam. The calculation results obtained via analytical method and those obtained using finite element method fit well with each other, verifying the rationality and correctness of the analytical method. The expression for analytical method is concise and can easily obtain the mapping relation between the structural vertical deformation and rail deformation using the displacement boundary conditions. The vertical deformation of the rail was proportional to the vertical deformation of same typical structure. Both inside and outside the rail deformation area, the length of rail deformation section did not change with structural vertical deformation. When there were simply supported beams at both ends of the continuous beam, the number of spans of simply supported beams had no significant effect on the rail deformation caused by the vertical deformation of typical continuous beam structures. When there were no simply supported beams, the settlement of side pier of continuous beam caused rail deformation similar to the staggered step of girder.

Fundamental Frequency Anomaly Around Cimeta River, Padalarang, West Java

Lembang Fault segment Cimeta and Cimandiri Fault segment Padalarang assumed to coincide at Padalarang, which lies at Ngamparah and Bojongkoneng district, Bandung, West Java. Padalarang is an area with high traffic and infrastructure conditions, such as freeway overpass named Cimeta bridge, rail bridge and soon-to-be tunnel of fast train Jakarta – Bandung. The presence of these faults becomes a threat to both residents and the infrastructures. We performed an investigation of seismic microzonation using a Horizontal Vertical Spectral Ratio in the area. Microtremor measurement has been done in 37 points widespread from the Cimandiri Fault segment Padalarang to Lembang Fault segment Cimeta. The method could provide information about the fundamental frequency and amplification factor of earthquake propagation to the site from the analysis of spectral ratio microtremor data. Fundamental frequency associated with the thickness of sedimentation meanwhile amplification factor indicates the impedance contrast at the site. The result shows that the fundamental frequency of Ngamprah and Bojongkoneng area around 1-6 Hz indicated deep sedimentation. However, we found an anomaly of the high fundamental frequency of 9 Hz at the Cimeta river. Therefore, we attempted to conduct another measurement around the area at different times and conditions. Three measurements of microtremor around the Cimeta river have shown that the area has high fundamental frequencies around 9-11 Hz. These results may indicate the presence of both bedrock and geological structure of Lembang Fault at the Cimeta river.

Development of a Test Level 4, Side-Mounted, Steel Tube Bridge Rail

A new, side-mounted, steel beam-and-post bridge rail was designed, crash tested, and evaluated according to safety performance guidelines included in the American Association of State Highway and Transportation Officials Manual for Assessing Safety Hardware (MASH) for Test Level 4 (TL-4). The new bridge rail system was designed to be compatible with multiple bridge decks, including cast-in-place concrete slabs and prestressed box beams. Additionally, the bridge rail was designed to remain crashworthy after roadway overlays up to 3 in. thick. The bridge rail was designed and optimized based on strength, installation cost, weight per foot, and constructability. The new bridge rail consisted of three rectangular steel tube rails supported by standard steel cross section, W6 × 15 steel posts spaced at 8 ft on-center. The upper rail was a 12 × 4 × ¼ in. hollow structural section (HSS) steel tube, and the lower two rails were 8 × 6 × ¼ in. HSS steel tubes. The top mounting heights for the upper, middle, and lower rails were 39 in., 32 in., and 20 in. above the surface of the deck, respectively. A new, side-mounted, post-to-deck connection was also developed that incorporated HSS steel spacer tubes that offset the posts 6 in. from the bridge deck and aligned the face of the bridge rail with the edge of the deck. Thus, the traversable width of the bridge was maximized. Three full-scale crash tests corresponding to the MASH TL-4 testing matrix were performed on the new bridge rail. All three crash tests successfully contained and redirected the vehicles and satisfied all MASH evaluation criteria.

Adequacy of Manitoba concrete bridge rail during truck platoon impacts and associated occupant risks

Platooning is an extension of Cooperative Adaptive Cruise Control (CACC) and forward collision avoidance technology; it allows lateral and longitudinal control of vehicles while they move in tight formations. Platooning is ideal for trucks as they usually travel long distances in highways as a group. It is necessary to understand if the existing roadside safety devices are adequate to resist the consecutive impacts at high speed that can occur due to errant truck platoons. It is also important to analyze the associated occupant risks during such impact events. A detailed analysis of the capacity and adequacy of Manitoba Concrete Bridge Rail using computer simulations, under Manual for Assessing Safety Hardware (MASH) Test Level 5 (TL5) criteria, is presented in this study. The study briefly discusses the methodology to run multiple impact computer simulations in LS-DYNA. The impact of the leading truck is validated using the known data from a full-scale crash test; then, the impact events involving the following trucks are simulated to understand the additional capacity of the roadside barrier. To assess the occupant risk, the flail space model (FSM) concept is utilised as per MASH criteria. Simulation results imply that catastrophic barrier failure and major injuries to the occupants are unlikely to occur during the truck platoon impact.

Development and Testing of a Test Level 4 Concrete Bridge Rail and Deck Overhang

A Manual for Assessing Safety Hardware (MASH)-compliant Test Level 4 (TL-4) concrete bridge rail was optimized to satisfy MASH TL-4 design loads, maximize vehicle stability, minimize installation costs, and mitigate the potential for deck damage by minimizing loads transfer to the deck. Additionally, the bridge rail was designed with a 39 in. installation height so that it would remain crashworthy after future roadway overlays up to 3 in. thick. The barrier had a front face with a 3-degree slope from vertical to promote vehicle stability during impacts while also providing some slope to allow for slipforming installations. Yield line theory was utilized to design both interior and end regions of the barrier. Further, minimum deck strengths were determined and a deck overhang design procedure was provided for users desiring to modify their existing deck details. Finally, MASH Test 4-12 was conducted on the new bridge rail to evaluate its safety performance criteria, damage to the barrier and a critical deck configuration, and its working width. In test 4CBR-1, the 22,198 lb single-unit truck impacted the concrete bridge rail at a speed of 57.6 mph and an angle of 16 degrees. The single-unit truck was successfully contained and redirected, and all safety performance criteria were within acceptable limits as defined in MASH. Therefore, test 4CBR-1 was determined to be acceptable according to MASH Test 4-12. Conclusions and recommendations for implementation are provided.

THE ROLE OF PEDESTRIAN BRIDGES IN THE FORMATION OF THE ARCHITECTURAL AND SPATIAL ENVIRONMENT OF THE CITIES

Therole, location and classification of pedestrian bridges that influence the formation and perception of architectural and spatialenvironment of citiesare determined. The history of thecreation of pedestrian bridge salong water and landscape obstacles is described, the functional influence off lows on the formation of pedestrian bridges is investigated.Pedestrian bridges are a separate type of structure intended only for pedestrian traffic, which determines their planning and design features. They are used to create pedestrian levels, separated from all of her types of traffic, at intersections with natural obstacles, roads, railwaysand streets. Pedestrian bridges also serve as decorative structures in city parks, exhibitions, etc. A pedestrian bridge over a river is built when there is no urban bridge in the immediate vicinity, and pedestrian traffic is rather in tense.Another important difference between pedestrian bridges and road or rail bridges is the psychology of perception. Large bridges are perceived only indirectly, passing on them by car, or looking from the side, at a considerable distance. Pedestrian bridges are perceived directly, in the movement of a pedestrian. Therefore, pedestrian bridges must have a scale commensurate with human scale.Separation of polyfunctional pedestrian bridges by spheres of in fluence on architectural and spatialen vironment is proposed.This article considers the projects of multifunctional bridges with the selection of such types of bridges as: street bridge, boulevard bridge, bridge building, bridge area, city bridge, attraction bridge. Then the article gives examples of projects and implemented solutions of multifunctional bridges.

Retrofitting of Damage Rail Bridge Girder and Its Performance Evaluation

Strengthening of prestressed girder using FRP has rarely been performed because prestressed girder has excellent strength under service load in both tension and compression. In this study, retrofitting of a 59-year-old prestressed bridge of Indian railway at Ratlam has been executed in which multiple vertical cracks visualized in tension zone and surface deterioration were observed. Due to this, deterioration speed of the trains over the bridge was restricted up to 20 km/h. The PSC girders of the bridge were strengthened by using prestressed carbon fiber. Serviceability of the structure was monitored before strengthening and after strengthening of the bridge girder. Deflections and natural frequencies after strengthening of girder were monitored for 481 days to ascertain the improvement and consistency in behavior of girder. After strengthening, the considerable decrement in deflection was noted by dint of the speed limit of the train which is recommended to increase up to 100 km/h.

Two-span bridge under moving load – numerical and experimental approach

From the point of view of bridge structures, the moving load is one of the most important components of the load. The analysis of the influence of moving load on bridges is carried out numerically or experimentally and can be traced in the literature since the year 1849. The first impulse was the collapse of the Chester Rail Bridge in England in the year 1847. The present paper analyses the effect of the moving load on a two-span bridge, both numerical and experimental way. The planar model of the vehicle and the bridge is adopted. The bridge is modeled as Bernoulli-Euler beam. The heavy vehicle is modeled as a discrete computational model with 8 degrees of freedom. Two approaches are used in numerical modeling. For the first time, the task is solved by the finite element method in the environment of the program system ADINA. The Newmark's method is used for the solution of equations of motion. The classic approach is used for the second time. A discrete computational model of a bridge with two degrees of freedom is used. Equations of motion are solved numerically in the environment of program system MATLAB by the Runge-Kutta 4th order method. The influence of vehicle speed on vertical deflections in the middle of individual bridge fields is analyzed in the speed range from 0 to 130 km/h with a step of 5 km/h. The detailed comparison of both numerical approaches is made at a vehicle speed of 70 km/h. The deflections of the bridge and the deflection of the vehicle are compared with each other. The correctness of the assumptions used in the numerical solutions was verified by measurement on a model beam in the laboratory. The results of the experimental tests were compared with the results of the numerical solution.

Interaction between Track and Long-Span Cable-Stayed Bridge: Recommendations for Calculation

Geometric nonlinearity (GN) and initial internal forces (IIFs) are the basic characteristics of cable-stayed bridges, but now there is no effective method for analyzing the effect of them on bridge-track interaction of continuous welded rail (CWR) on cable-stayed bridge. A method for reconstructing the displacement-force curve of ballast longitudinal resistance was put forward according to the deformation of cable-stayed bridges under the completed bridge state. A feasibility study on the method was conducted via two aspects of the force and deformation of CWR on a 5 × 40 m single-line simple-supported beam bridge with initial deformation. With the multi-element modeling method and the updated Lagrangian formulation method, a rail-beam-cable-tower 3D calculation model considering the GN and IIFs of cable-stayed bridge was established. Taking a (140 + 462 + 1092 + 462 + 140 m) twin-tower cable-stayed bridge as an example, the impacts of GN and IIFs on bridge-track interaction were comparatively analyzed. The results show that the method put forward to reconstruct ballast longitudinal resistance can prevent the impact of initial deformation of bridge and makes it possible to consider the effect of IIFs of cable-stayed bridge on bridge-track interaction. The GN and IIFs play important roles in the calculation of rail longitudinal force due to vertical bending of bridge deck under train load and the variance of cable force due to negative temperature changes in bridge decks and rails with rail breaking, and the two factors can reduce rail longitudinal force and variance of cable force by 11.8% and 14.6%, respectively. The cable-stayed bridge can be simplified as a continuous beam bridge with different constraints at different locations, when rail longitudinal force due to positive temperature changes in bridge deck and train braking is calculated.

A Novel Solution to Find the Dynamic Response of an Euler–Bernoulli Beam Fitted with Intraspan TMDs under Poisson Type Loading

This contribution considers a virtual experiment on the vibrational response of rail and road bridges equipped with smart devices in the form of damping elements to mitigate vibrations. The internal damping of the bridge is considered a discontinuity that contain a dashpot. Exact complex eigenvalues and eigenfunctions are derived from a characteristic equation built as the determinant of a 4 × 4 matrix; this is accomplished through the use of the theory of generalized functions to find the response variables at the positions of the damping elements. To relate this to real world applications, the response of a bridge under Poisson type white noise is evaluated; this is similar to traffic loading that would be seen in a bridge’s service life. The contribution also discusses the importance of smart damping and dampers to sustainability efforts through the reduction of required materials, and it discusses the role played by robust mathematical modelling in the design phase.

The Flight of Birds: A Novel in Twelve Stories by Joshua Lobb (2019)

This book feels good. The cover, designed by Miguel Yamin and Alexandra Guzmán, is smooth, matt laminated, with a luminous blue watercolour background that fades in places to white—designating clouds, perhaps, or sunspots? Three black cockatoos fly towards the top right-hand corner of the front cover. They are representations of the three black cockatoos who, in flight, came eye to eye with author Joshua Lobb as he walked across a rail bridge in North Wollongong, before they dropped and flew under the bridge.