Hamidreza Heydari

Iran University of Science and Technology

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Morteza Esmaeili

Iran University of Science and Technology

Jabbar Ali Zakeri

Iran University of Science and Technology

Nabie Khanie

Iran University of Science and Technology

J.N. Varandas

Universidade Nova de Lisboa

Reza Naseri

University of South Carolina

Mehdi Kamali

Iran University of Science and Technology

Sara Darvishi

Iran University of Science and Technology

Morteza Esmaeili

Isfahan University of Technology

Maziar Mokhtari

Iran University of Science and Technology

Jabbar Ali Zakari

Cooperative Institutions

Iran University of Science and Technology

University of Isfahan

University of South Carolina

University of Science and Technology

Korea University of Science and Technology

University of Shahrood

Yazd University

Universitat Politècnica de Catalunya

Beijing Jiaotong University

Technical and Vocational University

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Numerical Investigation of HMA Effect on Dynamic Behavoiur of Railway Track Transition Zone

DOAJ (DOAJ: Directory of Open Access Journals) (2018)

Alireza Gharighoran Hamidreza Heydari Ali Moeini

There are many structures along the railway tracks such bridges and culverts. The track vertical stiffness suddenly changes where the track passes over these structures. Therefore, these locations are called transition zones. Sudden track stiffness changes in these locations can lead to the asymmetric deformations, railway roughness, damage to the components of superstructure system. Studies shown that changing of the track stiffness along the railway lines is one of the main sources of tracks geometric damages. One of the most common places that the railway track stiffness changed along the railway lines are the culverts and bridges. The vertical stiffness change in these area causes the asymmetric deformations, rail roughness, damage of the components and as a result increasing the maintenance costs. One of the methods to solve the above problems is used to the hot mix asphalt (HMA) layer in adjacent of the culverts and bridges. In the present study, the behaviour of railway track in adjacent of culverts with HMA layer has been evaluated. For this purpose, a 3D finite element model of railway track culvert with HMA layer was built, and then different sensitivities on the geometric dimensions of HMA layer (including thickness and length) were analysed. Also based on analyse with exist a optimized layer of hot mixed asphalt around bridges structures the rail vertical displacement, ballasted layer vertical displacement and the normal stress in the middle of the subsgrade layer decreased approximately 19%, 22% and 36% respectively.

10.22065/jsce.2017.80167.1116

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Performance Evaluation of a Combined Transition System in Slab-Ballasted Railway Track Using a Vehicle-Track-Substructure Interaction Model

KSCE Journal of Civil Engineering (2023)

Hamidreza Heydari J.N. Varandas Jabbar Ali Zakeri Morteza Esmaeili

Slab

Ballast

Substructure

10.1007/s12205-023-1273-8

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Citations (5)

Closure to “Investigating Seismic Behavior of Ballasted Railway Track in Earthquake Excitation Using Finite-Element Model in Three-Dimensional Space” by Morteza Esmaeili and Hamidreza Heydari Noghabi

Journal of Transportation Engineering (2014)

Morteza Esmaeili Hamidreza Heydari

Closure (psychology)

10.1061/(asce)te.1943-5436.0000702

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Investigating the Influence of Auxiliary Rails on Dynamic Behavior of Railway Transition Zone by a 3D Train-Track Interaction Model

Latin American Journal of Solids and Structures (2017)

Hamidreza Heydari J.N. Varandas Morteza Esmaeili Jabbar Ali Zakeri

Abrupt track vertical stiffness variations along railway tracks can lead to increased dynamic loads, asymmetric deformations, damaged track components, and consequently, increased maintenance costs. The junction of slab track and ballasted track is one of the existing areas where vertical track stiffness can suddenly change, therefore requiring a transition zone that smoothes the track stiffness change. One of the methods for constructing the transition zone at the junction of slab and ballasted tracks is to install auxiliary rails along the transition zone. In the present study, the dynamic behavior of this type of transition zone was evaluated by a train-track interaction model. For this purpose, a 3D model of the railway track was made, representing the slab track, the transition zone, and the ballasted track. Then, the modeling results were validated by the results of field tests. Afterwards, in order to study the dynamic behavior of the transition zone with auxiliary rails, different sensitive analyses, such as vehicle speed, vehicle load, number of auxiliary rails and railpad stiffness, were performed with the model. The obtained results showed that the use of auxiliary rails reduced the rail deflection variations along the transition zone from 35% to 28% for low and medium speeds (120, 160, 200 km/h), and from 40% to 33% for high speeds (250, 300 km/h).

Slab

Critical speed

10.1590/1679-78253906

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Citations (39)

Field investigation on the lateral resistance of railway tracks including hot mix asphalt layer

Road Materials and Pavement Design (2016)

Morteza Esmaeili Hamidreza Heydari Ayoub Sayadi

One of the most important problems in the ballasted railway tracks is the inappropriate distribution of stress through the ballast over the subgrade layer, which causes damage to the super/substructure layers. Application of hot mix asphalt (HMA) layer in the forms of underlayment or full depth has been proposed in order to decline the stress concentration over the subgrade. Lack of sufficient track lateral resistance, especially in curved routes, is regarded as a concern when using this layer in ballasted railway tracks. Since there is not enough knowledge about the influence of the HMA layer on the lateral resistance of ballasted tracks, the present study was allocated to investigate the mentioned issue by a series of field tests. For this purpose, a test track (including different sections on asphalt layers, as underlayment HMA (with thickness of 100 and 150 mm) and full-depth HMA (with thickness of 100, 150 and 200 mm)) was constructed in Qom-Jamkaran railway line. Afterwards, a series of single tie push tests and track panel displacement tests were performed to measure the lateral resistance of all the test track sections. The results show that the lateral resistance of the common ballasted track is about 75–100% and 55–80% more than that of the ballasted track with underlayment HMA and full-depth HMA, respectively. Hence, on average, the lateral resistance of full-depth HMA track is about 15% more than that of underlayment HMA track.

Ballast

Asphalt pavement

Substructure

10.1080/14680629.2016.1250666

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Citations (20)

Formulation and Evaluation of the Ballast Shear Interlocking Coefficient Based on Analytical, Experimental and Numerical Analyses

Hamidreza Heydari Nabie Khanie Reza Naseri

The behavior of railway track under dynamic loads is affected by the ballast shear interlocking (BSI) mechanism, which involves the interaction between ballast particles. In this study, a close-form formulation for calculating of BSI stiffness was developed through a mathematical process and evaluated using experimental results. For this purpose, a laboratory test procedure is presented for determining the BSI stiffness and used to validate for the proposed formula. The resultsof laboratory tests showed that the BSI formulation accurately predicted BSI properties. Also, a numerical layered model was created to assess the sensitivity of the presented formula to the mechanical and dynamic characteristics of the ballasted track. It also specified the effect of various parameters of proposed formula on the dynamic behavior of railway track. The model was able to capture the resiliency of the track and highlighting the importance of considering BSI effects in railway track design. Using the model, it is demonstrated the efficiency of the developed methodologies and provided insight into factors contributing to track performance.Overall, this study provides a comprehensive understanding of ballast behavior with considering of the BSI effect on railway track and showed that BSI plays a crucial role in track resiliency. So, it should be certainly considered more precisely in track design, modelling and maintenance inspection to ensure safe and efficient railway operations. The methodology developed in this study has the potential to improve not only the modeling of ballasted railway track as multi-layer system but also the determining of shear interlocking effect through laboratory test.

Ballast

Interlocking

10.2139/ssrn.4511544

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Citations (1)

Evaluating the dynamic behavior of railway-bridge transition zone: numerical and field measurements

Canadian Journal of Civil Engineering (2023)

Hamidreza Heydari

Short-span bridges are one of the most frequent infrastructures along railway tracks where railway track stiffness suddenly changes. The sudden variation in the vertical stiffness of railway tracks increases dynamic loads and causes numerous defects in ballasted railroads. Therefore, improving the dynamic performance of railway tracks can be conducted by constructing countermeasures along the transition zone. In this regard, the approach slab is a practical technique used in railway-bridge transition zones. As the dimensional shape of the approach slab plays a significant role in the dynamic response of transition zones, this study evaluated the effects of its main geometric parameters. A three-dimensional model of the railway portal bridge, including the approach slab, was built using the finite element method and analyzed by imposing moving wheel loads as a series of acting force points along rail elements. The model was validated with field-obtained results acquired through a laser/camera-based measuring technique. Then, some sensitivity analyses were performed to find optimized geometric dimensions of approach slabs to improve the dynamic behavior of railway-bridge transition zones. Obtained results of the geometrical sensitivity analysis show that when the geometrically optimized approach slab is used along the railway-bridge transition zone, the displacements of rail and ballast are decreased by 24% and 18%, respectively.

Slab

Ballast

Bridge (graph theory)

10.1139/cjce-2022-0453

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Citations (5)

Evaluating the elastic sleeper efficiency in reduction of railway ground vibrations by in situ impact-response test

International Journal of Vehicle Noise and Vibration (2022)

Morteza Esmaeili Jabbar Ali Zakeri Hamidreza Heydari

10.1504/ijvnv.2022.10046110

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Citations (2)

A field investigation into the effect of under sleeper pads on the reduction of railway-induced ground-borne vibrations

Proceedings of the Institution of Mechanical Engineers Part F Journal of Rail and Rapid Transit (2015)

Jabbar Ali Zakeri Morteza Esmaeili Hamidreza Heydari

Train-induced vibrations have adverse effects on the structure of a track and its surroundings. It is thus necessary to study and control this issue through efficient measures. Special polyurethane pads that are placed under sleepers have been recently suggested as a solution to this problem. The use of these pads reduces vibrations at their source. These pads, called under sleeper pads (USPs), have numerous advantages and have found wide application in the railway industry. However, very few studies have been conducted on USPs; thus, this paper presents a field study that documents their effects on reducing vibration levels. Fifty stiff and 100 soft pads were prepared with the required technical and mechanical specifications. They were then installed onto concrete sleepers during the production process. These sleepers were installed at km-253 of the Mashhad–Tehran track. Train pass-by vibrations of passenger and freight trains were recorded using geophones placed at 0, 3, 7, 11, 15 and 19 m distances from each track axis (one track with and one without USPs). The results of the tests show that the maximum root-mean-square velocity was reduced by about 60%. Frequency analysis of the results demonstrates that the vibration reduction effect of the USPs appears above 40 Hz. The best efficiency levels of the USPs were observed in the range 40–80 Hz and the maximum USP efficiency occurred at the frequency of 50 Hz. At this specific frequency, the maximum vibration velocity level was decreased by more than 6.7 dB for all the considered distances (0, 3, 7, 11, 15 and 19 m).

Geophone

Ground vibrations

10.1177/0954409714565499

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Citations (40)

Evaluating the elastic sleeper efficiency in reduction of railway ground vibrations by in situ impact-response test

International Journal of Vehicle Noise and Vibration (2021)

Hamidreza Heydari Jabbar Ali Zakeri Morteza Esmaeili

10.1504/ijvnv.2021.123442

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Citations (6)