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The objective of the paper is to review railroad live loads in the United States. Railroad bridges are privately owned and the design codes are specified by American Railway Engineering and Maintenance of Way Association (AREMA). Over the years, there has been a considerable growth of railroad loads and, therefore, many older bridges were designed...
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... While the theoretical studies or for design purposes, the live load information of the truck has been presented by many international specifications. Here, the following idealization of truck loading will be adopted from AREMA specifications, this live load is presented in SI units as shown in Fig. 5 (Rakoczy & Nowak, 2018). AREMA (AREMA, 2006) This truckload is simulated in SAP2000 as a moving load passing through the pathways of two rail profile sections. ...
... Cooper E80 is the type of loading configuration suggested by AREMA, and the "80" value stands for the heaviest axle load in this load model in kilo pounds [21,22]. Cooper E80 consists of two steamed locomotives with four axles of 355.8 kN, two leading axles of 177.9 kN, and two tender wagons comprised of four axles of 231.3 kN. ...
... Cooper E80 load model[21,22] The transition at X and Y direction for both left/right and front/back is constrained; meanwhile, the transitions at X, Y, and Z are constrained for the bottom surface of the models. ...
Owing to the rapid increase in the demands of train speed and axle loads, the slab track has been introduced to replace the ballast in the classical ballasted track with reinforced concrete slab or asphalt-bearing layer to improve the track stability, strength, and durability. This paper aims to develop a new methodology for estimating the rail deformations for the most common slab track systems (BÖGL, Shinkansen, and RHEDA 2000. This methodology yielded the first design aid for slab track systems based on design equations and graphs for high-speed systems. Using a regression analysis of more than 300 finite element models which are validated by experimental tests, the relationship between the rail deflection, modulus of elasticity for subgrade and replacement, and the replacement thickness was determined for the most common slab tracks under the American (AREMA) and European (EN) loads. According to EN, it was found that the minimum modulus of elasticity for subgrade to fulfill the rail deflection criterion without a replacement soil ranges from 128 to 143 MPa for the most common slab track systems; meanwhile, for AREMA, it ranges from 59 to 70 MPa. Furthermore, for these slab track systems, one simple design chart was introduced to aid engineers with the design of the slab track replacement layer according to each design code.
... The researches on Continuously Welded Rails (CWR) on bridge mainly study the longitudinal interaction mechanism between track and bridge and the structural design of track and bridge to ensure that the track and bridge structure meet the requirements of strength and stability under temperature and train load [4][5]. ...
To study the longitudinal force of CWR on viaduct, a track-bridge-pier finite element model is established. Taking a multi-span simply supported beam with a maximum span of 32.7m of an elevated CWR as an example, the additional expansion and contraction forces, displacement between rail and beam and the force of pier are calculated, and whether the rail stress meets the requirements when setting constant resistance fasteners is checked. The results show that: (1) For the left and right lines, the maximum additional expansion forces of single strand rail are both 211.13kN, and the maximum relative displacements between beam and rail are both 6.572mm. (2) The maximum value of the additional expansion and contraction forces and the relative displacement between beam and rail of the same line occur at the same position. The left line is at ZFZ29 pier and the right line is at ZFS31 pier. (3) The maximum force of pier in this section is 500.80kN, and the pier numbers are ZFZ27 and ZFS29. (4) The rail stress is less than the allowable stress of 352MPa, and the rail strength meets the requirements.
... As for railway tracks specifically built on bridges and viaducts, several railway standards suggest different empirical relationships to estimate the dynamic effect on train loading as a function of bridge spans with no consideration to the train travel speed. For example, the AREMA (American Railway Engineering & Maintenance of Ways Association) manual (Rakoczy and Nowak, 2018) suggests that train dynamic wheel force can be estimated, using only bridge span as input parameter, via Equations 4 and 5. for L≥100ft (5) Where: L is the effect span length in feet. ...
The use of viaduct-elevated railway systems has become more common
in recent years. However, designers are faced with the unique challenge of
how to account for the dynamic effects of moving trains in the design of
viaduct railway structures. To overcome this challenge, designers resort to
relationships shown to be available in the literature. These are listed as
ballasted tracks, to estimate the dynamic loading. This approach can lead to
over-design which may result in a high construction cost. This is because
these relationships tend to recommend high degrees of dynamic loading due
to the constructed nature of ballasted tracks. The aim of this paper is to
investigate the effect of dynamic loading when moving trains are on viaduct
railway structures by using numerical modelling. The study concluded that
the dynamic behaviour of such structures is unique and if it is well
understood it can lead to more sustainable designs.
Current studies of Back-to-Back Mechanically Stabilized Earth Walls (BBMSE Walls) were conducted with uniform or single localized loading. In practice, this type of retaining wall may be subjected to the interference effect, which is the case of two railroads loading. The available design methods, such as Federal Highway Administration (FHWA) design guidelines, do not take this type of loading into account. The focus of this paper is to investigate the effect of the interaction distance between two railroad loadings on the internal and external stability of BBMSE walls under static conditions. The finite difference method incorporated in the Fast Lagrangian Analysis of Continua (FLAC) software is used for this analysis. Parametric studies were carried out by varying the interaction distance between two railroad loadings, to investigate its effects on soil bearing capacity, failure mechanism, maximum reinforcement load, horizontal facing displacement, and lateral earth pressure behind the reinforced zone.
This study presents a new vision-based deep learning method to monitor and evaluate the structural health of in-service
infrastructure. For this purpose, three diferent camera placements, including remote, structure-mounted, and drone-mounted
cameras, are proposed to capture the vibrations or displacements of bridges. The vision-based deep learning method is
verifed by an optical fow approach. Various techniques, such as visual data denoising and camera motion removal, are
utilized to process the test data for displacement measurements and extract the structural frequencies. Structural models of
bridges are analyzed to validate the measurements and assess the structural health of several pedestrian, trafc, and railway
bridges without interfering with trafc. Measurements in the feld experiments and results from the structural analysis
on tested bridges show that the proposed framework works successfully and can be potentially engineered to monitor the
structural health of existing bridges.
