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Cfd Simulation Of Passenger Hazard Risk At Railway Station Platforms Due To Explosive Air Blasts, Vivian Lawrence, Sakdirat Kaewunruen, Gianni Bartoli, Charalampos Baniotopoulos

Sakdirat Kaewunruen

Nonlinear 3d Finite Element Modeling For Structural Failure Analysis Of Concrete Sleepers/Bearers At An Urban Turnout Diamond, Minh Vu, Sakdirat Kaewunruen, Mario Attard

Sakdirat Kaewunruen

Railway urban turnout is a special track system used to divert a train from a particular direction or a particular track onto other directions or other tracks. It is a structural grillage system that consists of steel rails, points (or called “switches”), crossings, steel plates, rubber pads, insulators, fasteners, screw spikes, beam bearers (either tim- ber, polymer, steel, or concrete), ballast and formation. There are two types of turnouts, a conventional turnout and a tangential turnout. Standard conventional turnouts are designed typically for straight main line track. The combination of switch length, heel angle, and cross rate defines the turnout …

Rail Squats: Understand Its Causes, Severity, And Non-Destructive Evaluation Techniques, Sakdirat Kaewunruen, Makoto Ishida

Sakdirat Kaewunruen

Generally, rail squats are defined by the growth of any cracks that have grown longitudinally through the rail subsurface and some of the cracks propagating to the bottom of rails transversely have branched from initial longitudinal cracks with a depression of rail surface. The rail defects are commonly referred to as ‘squats’ when they were initiated from damage caused by rolling contact fatigue, and as ‘studs’ when they were associated with white etching layer caused by the transform from pearlitic steel due to friction heat generated by wheel sliding or excessive traction. Such rail surface defect induces wheel/rail impact and …

Achieving Carbon Efficiency In Construction And Maintenance Of Railway Turnouts, Crossovers And Diamonds, Sakdirat Kaewunruen, Steve Krezo, Olivia Mirza, Yapping He, Joseph M. Sussman

Sakdirat Kaewunruen

Railway turnouts, crossovers, and diamonds are special track systems used to divert a train from a particular direction or a particular track onto other directions or other tracks. It is a structural grillage system that consists of steel rails, points, crossings, steel plates, rubber pads, insulators, fasteners, screw spikes, beam bearers (either timber, polymer, steel or concrete), ballast and formation. Usually under dynamic and high-intensity impact loading conditions, structural components of the turnout tend to have relatively short lives compared with those of ordinary open railway tracks, resulting in frequent turnout re- construction and maintenance (ranging from every 10 to …

Severity And Growth Evaluation Of Rail Corrugations On Sharp Curves Using Wheel/Rail Interaction, Sakdirat Kaewunruen, Steve Marich

Sakdirat Kaewunruen

A railway network generally spans over a large distance so the structural health monitoring of such a rail infrastructure system is one of the critical challenges in rail industry practice. Especially in an underground/subway or elevated system, the facilities, resources and time period permitted for critical infrastructure inspection and maintenance is considerably limited. As a result, the automated inspection system of railway is in very high demand. Rail corrugation defect is the periodic, undulated or wave-like vertical alignment of rail surface. The wavelength and severity of rail corrugations is dependant to track structure, track geometry, traction system, rail vehicle behaviours, …

Under Sleeper Pads: Field Investigation Of Their Role In Detrimental Impact Mitigation, Sakdirat Kaewunruen, Alex M. Remennikov

Sakdirat Kaewunruen

Under sleeper pads (USPs) are the component installed under the concrete sleepers generally to improve railway track resilience. Initial development in Europe, particularly in Austria, has encouraged the adoption of the component around the world. In practice, the component has commonly been used in certain applications, mainly to moderate track stiffness in special locations such as turnouts, crossings, and level crossing. In heavy haul operation, the heavier wagons result in sturdier bogie structures, higher unsprung mass, and then higher level of wheel-rail interaction forces. Accordingly, the application of USPs to mitigate detrimental impact load consequence on track structure is presented …

Design Of Holes And Web Openings In Railway Prestressed Concrete Sleepers, Erosha Kahawatta Gamage, Sakdirat Kaewunruen, Alex M. Remennikov

Sakdirat Kaewunruen

As the crosstie beam in railway track systems, the prestressed concrete sleepers (or railroad ties) are principally designed in order to carry wheel loads from the rails to the ground. Their design takes into account static and dynamic loading conditions. It is evident that prestressed concrete has played a significant role as to maintain the high endurance of the sleepers under low to moderate repeated impact loads. In spite of the most common use of the prestressed concrete sleepers in railway tracks, there have always been many demands from rail engineers to improve serviceability and functionality of concrete sleepers. For …

Resilience-Based Design Of Precast Steel-Concrete Composites For Railway Track Slabs, Sakdirat Kaewunruen, Dane Wp Griffin, Olivia Mirza, Kenny Kwok

Sakdirat Kaewunruen

The relatively high turnover of timber sleepers (crossties in a plain track), bearers (skeleton ties in a turnout), and transoms (bridge cross beams) is responsible for producing greenhouse gas emissions 6 times greater than an equivalent reinforced concrete counterparts. This paper presents an innovative solution for the replacement of aging timber transoms installed on existing railway bridges along with the incorporation of a continuous walkway platform, which is proven to provide environmental, safety and financial benefits. Recent developments for alternative composite materials to replace timber components in railway infrastructure construction and maintenance demonstrate some compatibility issues with track stiffness as …

Impact Responses Of Prestressing Tendons In Railway Concrete Sleepers In High Speed Rail Environments, Sakdirat Kaewunruen, Alex M. Remennikov

Sakdirat Kaewunruen

Prestressed concrete sleepers (or railroad ties) are designed in order to carry and transfer the wheel loads from the rails to the ground and are installed as the crosstie beam support in railway track systems. They are subjected to impact loading conditions that are resulted from train operations over wheel or rail abnormalities, such as flat wheels, dipped rails, crossing transfers, rail squats, corrugation, etc. The magnitude of the shock load relies on various factors such as axle load, types of wheel/rail imperfections, speeds of vehicle, track stiffness, etc. This paper demonstrates the development of finite element modelling to evaluate …

Finite Element Modelling Of Modular Precast Composites For Railway Track Support Structure – A Battle To Save Sydney Harbour Bridge, Dane Griffin, Olivia Mirza, Kenny Kwok, Sakdirat Kaewunruen

Sakdirat Kaewunruen

Railway networks in Australian alone require replacing a large amount of aging timber components in excess of 280,000 m3 per year. The replacement of timber track components is responsible for producing greenhouse gas emissions 6 times greater than equivalent reinforced concrete counterparts. Sydney Harbour Bridge presently experiences similar problem. A feasibility study to develop an innovative solution for the replacement of aging timber transoms installed on the Sydney Harbour Bridge was conducted to evaluate environmental, safety and financial benefits. The development of alternative composite structure to replace the timber components overcomes some potential compatibility issues with track stiffness as well …

Field Monitoring Of Rail Squats Using 3d Ultrasonic Mapping Technique, Sakdirat Kaewunruen, Makoto Ishida

Sakdirat Kaewunruen

Rail squats and studs are typically classified as the propagation of any cracks that have grown longitudinally through the subsurface. Some of the cracks could propagate to the bottom of rails transversely, which have branched from the initial longitudinal cracks with a depression of rail surface. The rail defects are commonly referred to as ‘squats’ when they were initiated from damage layer caused by rolling contact fatigue, and as ‘studs’ when they were associated with white etching layer caused by the transform from pearlitic steel due to friction heat generated by wheel sliding or excessive traction. Such above-mentioned rail defects …

Think Outside The Box: New Materials, Design Application, And Performance Of Railway Turnout Bearers, Sakdirat Kaewunruen

Sakdirat Kaewunruen

Railway turnout systems are a main feature in railway tracks. There are two types of turnout support structures, which can be designed to be either a slab or a cluster of discrete bearers. The choice of turnout support system depends on asset management strategy of the rail operators or maintainers. This paper will focus on the discrete turnout bearer system where turnout alignments, settlement and deformation are comparatively more flexible and retrievable by routine ballast tamping. It embraces the consideration of new materials for use as a turnout bearer. Traditional bearer materials are timber, steel, and concrete. Recent developments have …

Free Vibrations Of Interspersed Railway Track Systems In Three-Dimensional Space, Sakdirat Kaewunruen, Alex M. Remennikov, Akira Aikawa, Hirotaka Sakai

Sakdirat Kaewunruen

Statistically, the actual loading conditions for railway tracks are rather dynamic and transient. The dynamic loadings due to train and track interactions redistribute from the rails to the rail pad, from the rail pad to the railway sleeper, and from the railway sleeper to the underlying ground. Commonly, railway sleeper in track systems is modeled as a beam on elastic foundation. This study makes use of a calibrated finite element model of railway sleepers in a track system, in order to investigate the resonant frequencies and associated mode shapes of railway components in interspersed track systems. The numerical model takes …

Dynamic Responses Of Railway Bridge Ends: A Systems Performance Improvement By Application Of Ballast Glue/Bond, Sakdirat Kaewunruen

Sakdirat Kaewunruen

Accelerated deterioration of railway bridge approaches often induces downtime or restricted railway operation; and importantly causes more frequent maintenance, which is costly and time-consuming. Such deterioration is believed to occur because of high dynamic impact loading from: the difference of stiffness between the railway track and the bridge; and the poor condition of the track support at the bridge ends. The abrupt change in track stiffness often causes accelerated degradation of the track geometry and components and poor ride quality, demanding higher maintenance. There are a number of improvement programs that have been implemented in order to provide a smooth …

Monitoring In-Service Performance Of Fibre-Reinforced Foamed Urethane Sleepers/Bearers In Railway Urban Turnout Systems, Sakdirat Kaewunruen

Sakdirat Kaewunruen

Special track systems used to divert a train to other directions or other tracks are generally called \'railway turnout\'. A traditional turnout system consists of steel rails, switches, crossings, steel plates, fasteners, screw spikes, timber bearers, ballast and formation. The wheel rail contact over the crossing transfer zone has a dip-like shape and can often cause detrimental impact loads on the railway track and its components. The large impact also emits disturbing noises (either impact or ground-borne noise) to railway neighbors. In a brown-field railway track where an existing aged infrastructure requires renewal or maintenance, some physical constraints and construction …

Finite Element Modelling Of Railway Turnout Systems, Sakdirat Kaewunruen

Sakdirat Kaewunruen

Finite Element Modelling of Railway Turnout System, RMS Annual Bridge Conference, Bridge and Structural Engineering, Bridge Journey through Partnerships, 04 - 05 December 2013, Sydney

Bridge-Track Interaction Under Elevated Temperatures, Sakdirat Kaewunruen

Sakdirat Kaewunruen

This paper presents the adaptability to short-term climate variability and extreme events of existing infrastructures in Australia, especially railway track bridges. The main objective of this research was to analyse the interaction between the track and bridge under elevated temperatures. The scope of work was to evaluate the behaviour of the track and bridge interaction throughout temperature ranges experienced in summer periods whereas the expansion and contraction of materials are different in nature. This investigation was emphasised on the differential longitudinal behaviours of railway track and bridge structure. A nonlinear 3D finite element model of a railway bridge (ballast top) …

Advances In Rail Track Infrastructure Research And Practice, Manicka Dhanasekar, Alex M. Remennikov, Sakdirat Kaewunruen, Nannan Zong

Sakdirat Kaewunruen

Railway infrastructure plays a critical role in urban development, mobility, and economic growth of society. This focus issue of the Electronic Journal of Structural Engineering is devoted to a special theme, “Advances in Rail Track Infrastructure and Practice - ARTRP”. It contains articles, which were rigorously peer reviewed and accepted from a list of invited manuscripts that demonstrate significant innovation in the area of the structural engineering aspects of the rail track infrastructure. Over the past century or two, rail industry slowly but steadily evolved through significant innovations in the industry; academic research in rail is relatively new. Rail is …

On The Residual Energy Toughness Of Prestressed Concrete Sleepers In Railway Track Structures Subjected To Repeated Impact Loads, Sakdirat Kaewunruen, Alex M. Remennikov

Sakdirat Kaewunruen

Installed as the crosstie beam support in railway track systems, the prestressed concrete sleepers (or railroad ties) are designed in order to carry and transfer the wheel loads from the rails to the ground. It is nowadays best known that railway tracks are subject to the impact loading conditions, which are attributable to the train operations with either wheel or rail abnormalities such as flat wheels, dipped rails, etc. These loads are of very high magnitude but short duration, as well as there exists the potential of repeated load experience during the design life of the prestressed concrete sleepers. These …

In Situ Performance Of A Complex Urban Turnout Grillage System Using Fibre-Reinforced Foamed Urethane (Ffu) Bearers, Sakdirat Kaewunruen

Sakdirat Kaewunruen

A full-scale trial to investigate in-situ behaviours of a turnout grillage system using an alternative material, ‘fibre-reinforced foamed urethane (FFU)’ bearers, has been carried out at a complex turnout junction under heavy mixed traffics at Hornsby, New South Wales, Australia. The turnout junction was renewed using the FFU bearers altogether with new special track components. Influences of the FFU bearers on track geometry (recorded by track inspection vehicle ‘AK Car’ and based on survey data), track settlement, track dynamics and acoustic characteristics have been measured. Operational train pass-by measurements have been analysed to evaluate the effectiveness of the replacement methodology. …

Railway Bridge-Track Interaction Under Elevated Temperatures, Sakdirat Kaewunruen

Sakdirat Kaewunruen

This paper presents the adaptability to short-term climate variability and extreme events of existing infrastructures in Australia, especially railway track bridges. The main objective of this research was to analyse the interaction between the track and bridge under elevated temperatures. The scope of work was to evaluate the behaviour of the track and bridge interaction throughout temperature ranges experienced in summer periods whereas the expansion and contraction of materials are different in nature. This investigation was emphasised on the differential longitudinal behaviours of railway track and bridge structure. A nonlinear 3D finite element model of a railway bridge (ballast top) …

Acoustic And Dynamic Characteristics Of A Complex Urban Turnout Using Fibre-Reinforced Foamed Urethane (Ffu) Bearers, Sakdirat Kaewunruen

Sakdirat Kaewunruen

A special track system used to divert a train to other directions or other tracks is generally called ‘railway turnout’. A traditional turnout system includes rails, switches, crossings (special track components), steel plates, fasteners, screw spikes, timber bearers, ballast and formation. The wheel rail contact over the crossing transfer zone has a dip-like shape and can often cause detrimental impact loads on the railway track and its components. The large impact also emits disturbing noises (either impact or ground-borne noise) to railway neighbors. In a brown-field railway track where an existing aged infrastructure requires renewal or maintenance, some physical constraints …

Modern Rail Innovation In Japan, Sakdirat Kaewunruen

Sakdirat Kaewunruen

This presentation was invited by Engineers Australia to discuss the importance of railway experience in Japan. Abstract: Rail transport has become one of the most desirable and environmental-friendly means for mass transportation, especially when the up-and-coming peak oil crisis has threatened and discredited many other modes of transport (including traditional car vehicles, trucks, and air planes) from being economical, efficient and sustainable. In this presentation, the modern rail systems in Japan, which cover metro, local and high speed rails, will be discussed together with the infrastructure development, network strategy, ticketing and sources of revenues. Because Japan is the pioneer of …

Influence Of Ballast Conditions On Flexural Responses Of Railway Concrete Sleepers, Sakdirat Kaewunruen, Alex M. Remennikov

Sakdirat Kaewunruen

Railway sleepers in track systems are usually modeled using the beam on elastic foundation theory. In reality, the sleeper-supported ballast is of highly frictional granular media but does not provide any tensile resistance. This paper presents a finite element model of a railway sleeper in a track system, taking into account the tensionless nature of the elastic support. The highlight of this paper is the effect of ballast distributions on the flexural responses of railway sleepers in track systems. Using a finite element package STRAND7, the finite element model updating of the concrete sleeper was earlier developed and validated against …

Sleepers Exposed: New Innovations In Rail Design, Sakdirat Kaewunruen

Sakdirat Kaewunruen

No one would deny that our rail network makes life much easier, and trains are widely considered to be the world's safest mode of transport. Bearing this in mind, the idea of decreasing the weight of railway sleepers, or increasing the load they carry may make passengers and associates of the rail industry sceptical as regards their own safety or the integrity of their goods and assets.