Ali Reza
@iust.ac.ir
Railway tracks and Structures/School of Railway Engineering
Iran University of Science and Technology/Assistant Professor
EDUCATION
PhD in Railway Engineering
RESEARCH INTERESTS
Railway Tracks, Ballast Mechanical Properties, Sleeper Behavior, Modal Analysis, Train-induced Vibration, Steel Structures, Moment Connections
Scopus Publications
Scholar Citations
Scholar h-index
Scholar i10-index
Scopus Publications
Javad Sadeghi, Ali Reza Tolou Kian, Ali Khanmoradi, and Mohammad Chopani
Elsevier BV
Javad Sadeghi, Ali Reza Tolou Kian, Mohammad Chopani, and Ali Khanmoradi
Elsevier BV
Javad Sadeghi, Ali Reza Tolou Kian, and Mosarreza Fallah
American Society of Civil Engineers (ASCE)
Abstract Considerable parts of worldwide railway networks cross deserts where there are frequent sandstorms, which cause contamination of ballast. One of the most important challenges for railway i...
Javad Sadeghi, Ali Reza Tolou Kian, Hossein Ghiasinejad, Mosarreza Fallah Moqaddam, and Sepehr Motevalli
Elsevier BV
Ali Reza Tolou Kian, Javad Sadeghi, and Jabbar-Ali Zakeri
Elsevier BV
Ali Reza Tolou Kian and Ardeshir Deylami
Thomas Telford Ltd.
Due to their excellent biaxial bending strength, box columns are widely employed in countries with high seismic risk such as Iran and Japan. Although extensive research into the moment connections between I-beams and wide-flange columns has been conducted, a review of the literature indicated that studies on I-beam to box column moment connections are insufficient. To fill this gap, the cyclic behaviour of a two-sided moment connection of an I-beam to built-up box column was studied in this work. Non-linear finite-element models of the connection were developed and validated using test results available in the literature. In the studied connection, the beam flanges are joined to the column flange through flange plates. To reinforce the connection, vertical top and bottom rib plates were welded to the column flange and the flange plates. A parametric study was carried out to investigate the influences of the geometry of the rib plates on the behaviour of the connection. The results indicated that rib plates decrease the stress on the groove weld between the flange plates and the column flange and have insignificant influences on the global responses of the connection.
Ali Reza TolouKian, Javad Sadeghi, and Jabbar-Ali Zakeri
Thomas Telford Ltd.
Significant parts of railway lines in most of the Middle East and Asian countries are in sandy and desert areas. Contamination of tracks (in particular the ballast layer) caused by frequent sand storms in the desert is an important challenge for railway industries. Despite a large number of reported railway accidents caused by the loss of shear strength in the contaminated ballast layer, there is a lack of sufficient studies on the effect of sand contamination on ballast shear strength. In response to this need, extensive laboratory tests on clean and sand-contaminated ballasts were conducted, using a large-scale direct shear test machine designed and constructed in this research. Ballast samples with different dosages of sand contamination were tested. The results obtained are discussed leading to a better understanding of ballast behaviour when contaminated with various amounts of sand. The results show that sand contamination reduces the shear strength and angle of effective shearing resistance of the ballast. The critical percentage of ballast contamination, after which the ballast faces substantial reduction in its mechanical properties, was derived. The results obtained have improved the current ballast maintenance approach by providing the possibility of a more accurate planning of ballast cleaning and renewals.
Javad Sadeghi, Jabbar-Ali Zakeri, and Ali Reza Tolou Kian
Thomas Telford Ltd.
Railway track behaviour with unsupported prestressed sleepers has been investigated in the literature. However, some of the important factors – such as prestressing forces, variations of the sleeper cross-section along its length, losing or recovering contact between the sleeper and the ballast layer – have been omitted. These limitations have been addressed in this research. The effects of unsupported sleepers on the dynamic behaviour of railway track have been investigated, using an improved three-dimensional numerical model of track developed here. The validity of the model is evaluated by comparing the results obtained from the model with experimental results (obtained in this research and available in the literature). The influences of the size of the gap between the sleeper and the underlying ballast, the vehicle speed and the number of unsupported sleepers on the track dynamic behaviour were investigated. The effects of the various unsupported conditions of sleepers on the rail seat load, sleeper bending moment and sleeper–ballast contact force at various train speeds were illustrated. It was shown that consideration of sleeper prestress forces, detailed geometry of the sleepers and a more realistic assumption for the sleeper–ballast contact has considerably improved the accuracy of the results obtained from theoretical models.
A. Kian, J. Zakeri and J. Sadeghi
Ballast layer has an important role in vertical stiffness and stability of railway track. In most of the Middle East countries and some of the Asian ones, significant parts of railway lines pass through desert areas where the track (particularly ballast layer) is contaminated with sands. Despite considerable number of derailments reported in the sand contaminated tracks, there is a lack of sufficient studies on the influences of sand contamination on the ballast vertical stiffness as the main indicator of track stability. Addressing this limitation, the effects of sand contamination on the mechanical behavior of ballast were experimentally investigated. For this purpose, laboratory tests (plate load test) on ballast samples with different levels of sand contamination were carried out. The results obtained were analyzed leading to derive mathematical expressions for the strain modulus (EV) as a function of the ballast level of contamination. The EV was used as an index for evaluation of the load-deformation characteristics and bearing capacity of track substructure. The critical limit of sand contamination, after which the EV of the ballast reduces drastically, was obtained. It was shown that the obtained research results improve the current track maintenance approach by providing key guides for the optimization of ballast maintenance planning (the timing of ballast cleaning or renewal).
Javad Sadeghi, Ali Reza Tolou Kian, and Amin Shater Khabbazi
American Society of Civil Engineers (ASCE)
AbstractThere has been a significant increase in axle loads, speed, and traffic volumes in railway transport systems in recent years. This has stimulated improvements of track component characteristics from the aspects of stability, durability, and energy absorption. This research has focused on concrete sleepers as the main element of the track superstructure. It investigates the efficiency and practicability of using steel fibers in improvements of sleeper characteristics, including load-carrying capacity, energy absorption, and dynamic properties. This is done through a comprehensive experimental work. Extensive static and dynamic tests were carried out on the prestressed concrete sleepers designed and manufactured with various amounts of hybrid steel fibers (a mixture of short and long fibers) and different numbers of prestressing steel wires. The research results have indicated that the use of hybrid steel fibers in the sleepers leads to an increase in load-carrying capacity, energy absorption, and c...