ORCID Profile
0000-0002-1532-5719
Current Organisations
University College Dublin
,
University of Wollongong
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Research Topics
In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Top 5 Research Topics
ANZSRC Field of Research (FoR)
Civil Engineering | Structural Engineering | Construction Materials | Structural engineering | Manufacturing engineering | Civil Geotechnical Engineering | Tribology | Mining engineering | Manufacturing processes and technologies (excl. textiles) | Civil engineering | Information Systems Management | Interdisciplinary Engineering Not Elsewhere Classified | Research, Science And Technology Policy | Risk Engineering (excl. Earthquake Engineering) | Structural Engineering | Interdisciplinary Engineering |
ANZSRC Socio-Economic Objective (SEO)
Civil Construction Design | Commercial Construction Design | Cement and Concrete Materials | Technological and organisational innovation | Industrial Construction Design | Civil Construction Processes | Environmentally Sustainable Construction not elsewhere classified | Emerging Defence Technologies | Personnel | Expanding Knowledge in Built Environment and Design | Other | Civil | Construction Materials Performance and Processes not elsewhere classified | Cement Products and Concrete Materials | Electricity, gas and water services and utilities | Rail Infrastructure and Networks
Related Links
Publications
Dynamic Crack Propagations in Prestressed Concrete Sleepers in Railway Track Systems Subjected to Severe Impact Loads
Publisher: American Society of Civil Engineers (ASCE)
Date: 06-2010
An experimental study on shear behaviour of fully grouted rock bolt under static and dynamic loading conditions
Publisher: Elsevier BV
Date: 02-2023
Seismic Behavior and Deterministic Design Procedures for Steel V-Braced Frames
Publisher: SAGE Publications
Date: 05-1998
DOI: 10.1193/1.1586004
Abstract: This paper presents an approach for designing low-rise steel framed buildings with inverted-V-bracing for severe earthquakes. A deterministic design philosophy is used with respect to earthquake-resisting ductile steel braced frames. Seismic behavior of steel frames with inverted-V-bracing is discussed. A series of dynamic analyses was performed on a two-story inverted-V-Braced frame, subjected to near-field ground motions. Ground shaking of this type may be expected in New Zealand, within 10 to 15 km from the Wellington fault, or in the United States in Seismic Zone 4. Post-elastic behavior of braces, beams, and columns is discussed. From the results of dynamic analyses, the interrelations between the seismic forces in frame members are identified. The expressions for the maximum expected seismic design actions in those elements are derived, following the capacity design method. It is believed that this approach will result in stronger and more ductile frames that are capable of resisting the near-field ground motions.
Benefits of using sea sand and seawater in concrete: a comprehensive review
Publisher: Informa UK Limited
Date: 29-08-2019
Experiments into impact behaviour of railway prestressed concrete sleepers
Publisher: Elsevier BV
Date: 12-2011
Investigation of trees as natural protective barriers using simulated blast environment
Publisher: Elsevier BV
Date: 12-2021
Novel hybrid FRP tubular columns for sustainable mining infrastructure: Recent research at University of Wollongong
Publisher: Elsevier BV
Date: 05-2014
Novel hybrid FRP tubular columns with large deformation capacity: Concept and behaviour
Publisher: Elsevier BV
Date: 03-2019
Current state of practice in railway track vibration isolation: an Australian overview
Publisher: Informa UK Limited
Date: 2016
DYNAMIC RESPONSES OF RAILWAY ULTRA-HIGH-STRENGTH CONCRETE SLEEPERS UNDER EXTREME IMPACT LOADING
Publisher: Institute of Structural Analysis and Antiseismic Research School of Civil Engineering National Technical University of Athens (NTUA) Greece
Date: 2017
Modelling Railway Prestressed Concrete Sleepers (Crossties) With Holes and Web Openings
Publisher: Elsevier BV
Date: 2016
Development and performance evaluation of large-scale auxetic protective systems for localised impulsive loads
Publisher: SAGE Publications
Date: 24-06-2019
Abstract: Cellular core structures with a negative Poisson’s ratio, also known as auxetic core structures, are gaining attention due to their unique performance in sandwich panel systems for protecting critical infrastructures and military vehicles that are at high risk of blast and impact loads due to accidental and deliberate events. To help develop a high-performance protective system, this article outlines the performance evaluation of five different auxetic cell configurations based on a quantitative/qualitative review of an experimental load–deformation relationship of three-dimensional-printed auxetic panels from nylon plastics and the overall performance evaluation of metallic re-entrant honeycomb core sandwich panels as one type of lightweight protective system under static and dynamic loads via experimental testing and numerical simulations. The re-entrant honeycomb design displayed the most consistent auxetic behaviour. Quasi-static compression and drop hammer impact tests were performed using the proposed full-scale sandwich panel design with two different configurations as a protective system for concrete wall structures in combination with plastic face plates. The effect of the internal angle of the re-entrant honeycomb design and the effect of the core material under static and dynamic loads were evaluated using full-scale sandwich panels. Furthermore, two separate materials – acrylonitrile butadiene styrene and low-density polyethylene – were used as face plates, and the low-density polyethylene was effective for lightweight and smooth load transferring and distribution into the auxetic core. Auxetic panel deformation under static and dynamic load was examined using a normal speed camera and high-speed video recording data and all auxetic panels indicated excellent systematic crushing behaviour with drawing materials into the load path to effectively resist the impact load. Numerical simulations were performed using LS-DYNA and indicated good agreement with the experimental results. Finally, protective systems utilising sandwich panels with a re-entrant honeycomb core indicated strong potential for the development of high-performance lightweight impact-resistant protective systems.
Properties and Application of Sea Sand in Sea Sand–Seawater Concrete
Publisher: American Society of Civil Engineers (ASCE)
Date: 12-2020
General purpose code for steel structures optimal design
Publisher: Elsevier BV
Date: 06-1992
Numerical simulations of response of tubular steel beams to close-range explosions
Publisher: Elsevier BV
Date: 02-2015
Editorial: New conversations in development studies
Publisher: Wiley
Date: 08-2021
DOI: 10.1002/JID.3569
Approximating a far-field blast environment in an advanced blast simulator for explosion resistance testing
Publisher: SAGE Publications
Date: 13-03-2020
Abstract: While the current state of blast-resistant design methods is based largely on empirical observations of actual explosive testing or numerical simulations, experimental testing remains the ultimate method for validating blast protection technologies. Field trials for performing systematic experimental studies are exceedingly expensive and inefficient. Conventional blast simulators (shock tubes) enable blast testing to be performed in a safe and controlled laboratory environment but are significantly deficient. The Australian National Facility of Physical Blast Simulation based on the ‘Advanced Blast Simulator’ concept was established to address the shortcomings of conventional blast simulators (shock tubes). The blast simulator at the National Facility of Physical Blast Simulation is a state-of-the-art design having a test section of 1.5 × 2.0 m with dual-mode driver able of operating with either compressed gas or gaseous detonation modes. The simulator is capable of a range of blast-test configurations such as full-reflection wall targets and diffraction model targets. This article aims to demonstrate the ability of the Advanced Blast Simulator in accurately generating a far-field blast environment suitable for high-precision and repeatable explosion testing of various building components. Blast pressure-time histories generated with the Advanced Blast Simulator are validated against equivalent TNT free-field curves reproduced with Conventional Weapons Effects Program. Numerical models based on Computational Fluid Dynamics were developed in ANSYS FLUENT to accurately characterise and visualise the internal flow environment of the National Facility of Physical Blast Simulation Advanced Blast Simulator. The Computational Fluid Dynamics model was also used to explain experimental observations and to determine density and dynamic pressure information for comparisons with free-field explosion conditions.
Experimental investigation and simplified modeling of response of steel plates subjected to close-in blast loading from spherical liquid explosive charges
Publisher: Elsevier BV
Date: 03-2017
Analysis of Energy Accumulation and Dissipation of Coal Bursts
Publisher: MDPI AG
Date: 11-07-2018
DOI: 10.3390/EN11071816
Experimental Study on FRP-Strengthened Steel Tubular Members under Lateral Impact
Publisher: American Society of Civil Engineers (ASCE)
Date: 10-2017
Nothing to hide: Commitment to, compliance with, and impact of the special data dissemination standard
Publisher: Wiley
Date: 25-10-2018
DOI: 10.1111/ECPO.12100
Impact behaviour of pre-compressed hollow and concrete filled mild and stainless steel columns
Publisher: Elsevier BV
Date: 05-2014
Dynamic properties of railway track and its components: recent findings and future research direction
Publisher: British Institute of Non-Destructive Testing (BINDT)
Date: 2010
Health-system equity, egalitarian democracy and COVID-19 outcomes: An empirical analysis
Publisher: SAGE Publications
Date: 09-01-2021
Abstract: The COVID-19 pandemic has led to a spate of studies showing a close connection between inequitable access to health care, welfare services and adverse outcomes from the pandemic. Others have argued that democratic governments have generally failed relative to more autocratic ones, simply because autocrats can make the hard choices required for stemming the spread of viruses. We address this question by asking whether more ‘egalitarian’ forms of democracy matter, given that they contain more equitable health-care access and societal infrastructure, such as social capital and trust. We use standard regression techniques, including instrumental variables analysis addressing endogeneity on COVID-19 testing and deaths data as of the end of May and beginning of September. We use novel data from the Varieties of Democracy Project on health-system equity and egalitarian democracy. Our results suggest that more equitable access to health care increases testing rates and lowers the death rate from COVID-19. Broader egalitarian governance, measured as egalitarian democracy, however, shows the opposite effect. Thus, factors associated with health-care capacity to reach and treat matter more than broader societal factors associated with social capital and trust. The results are robust to alternative testing procedures, including instrumental variable technique for addressing potential endogeneity. Despite a great deal of public health focus on how equitable governance helps fight the adverse effects of so-called neoliberal pandemics, we find that broadly egalitarian factors have had the opposite effect on fighting COVID-19, especially when an equitable health system has been taken into account. Fighting disease, thus, might be more about the capacity of health systems rather than societal factors, such as trust in government and social capital.
Sensitivity analysis of free vibration characteristics of an in situ railway concrete sleeper to variations of rail pad parameters
Publisher: Elsevier BV
Date: 11-2006
Numerical Modeling and Performance Assessment of FRP-Strengthened Full-Scale Circular-Hollow-Section Steel Columns Subjected to Vehicle Collisions
Publisher: American Society of Civil Engineers (ASCE)
Date: 06-2020
Blast Effects on Hyperloop’s Cylindrical Thin-Shell Structures
Publisher: MDPI AG
Date: 10-2023
Toughness of Railroad Concrete Crossties with Holes and Web Openings
Publisher: MDPI AG
Date: 11-01-2017
Close-in blast resistance of large-scale auxetic re-entrant honeycomb sandwich panels
Publisher: SAGE Publications
Date: 27-11-2021
Abstract: The protection of critical infrastructure, including government buildings, airports, religious buildings, military buildings and military vehicles, which are at risk to blast loads, has become important due to increasing terrorist activities in recent years. Sacrificial cladding systems based on negative Poisson’s ratio core topologies have recently received more attention as a protective technology due to its excellent energy absorption capability. In this study, field blast tests were performed on metallic re-entrant honeycomb-cored sacrificial cladding systems as protective structures for steel plate structures. This study focused on the near-field blast loading conditions where liquid Nitromethane (NM) spherical charges were detonated in close proximity to the main structure. Two 6 mm thick mild steel plates and two steel plates protected with re-entrant honeycomb-cored sacrificial cladding systems were among the specimens tested. The proposed auxetic cladding system was fabricated from aluminium sheets using a novel in-house built folding machine. Numerical simulations were conducted utilising LS-DYNA software and the Blast Impact Impulse Model (BIIM). The results obtained from the numerical simulations are in good agreement with the experimental results. It was found that the deformation pattern of the sacrificial auxetic cladding system varies with the intensity of the blast loading, and there is a limit at which the proposed protective system ceases to effectively absorb the applied blast loading. The variation of negative Poisson’s ratio of the system with blast loading was studied. It was found that the auxetic cladding system could become a solid projectile leading to damage lification for very close-range blast loads due to rapid densification of the auxetic core. The proposed cladding systems with narrow re-entrant angles performed well under blast loads due to relatively low stiffness of the panels. Finally, the optimisation study was performed for the protective system. Overall, the experimental and numerical results assure that auxetic-based cladding systems are suitable for applications requiring blast protection such as armoured vehicles and critical physical infrastructure but need to be carefully designed for the given blast threat to prevent overloading of the protected structures.
Dynamic Capacity Reduction of Railway Prestressed Concrete Sleepers Due to Surface Abrasions Considering the Effects of Strain Rate and Prestressing Losses
Publisher: World Scientific Pub Co Pte Ltd
Date: 20-12-2018
DOI: 10.1142/S0219455419400017
Abstract: In reality, railway prestressed concrete sleepers frequently experience significant aggressive loading conditions and harsh environments. Especially in sharp curves, lateral loading of train wheels in combination with incompressible hydraulic pressure aggravates the lateral oscillation and abrades the surface of sleepers right underneath the rail seats. Many investigators in the past have proposed various material models to improve abrasive resistance characteristics, but those have been mostly applied to the new products using novel materials such as fiber-reinforced concrete. On the other hand, prestressed concrete sleepers have been used for over 50 years and they have become worn over time. This paper highlights the dynamic capacity evaluation of worn sleepers, which will lead to predictive models that could be realistically applied to asset management of railway lines. This paper presents an investigation into the structural capacity reduction in worn railway prestressed concrete sleepers considering the effects of strain rate and loss of prestressing steel. RESPONSE2000 has been used to evaluate the residual dynamic capacity based on the modified compression field theory. Unprecedented parametric studies have been carried out to determine the influences of uniform and gradient prestress losses on prestressed concrete capacity. The study results exhibit the level of wear and tear, which is critical to the dynamic integrity of sleepers required for immediate replacement. The outcome of this study will help improve the practical maintenance and monitoring technology in railway industry.
Performance of a hybrid GFRP-concrete beam subject to low-velocity impacts
Publisher: Elsevier BV
Date: 12-2018
The development of specialised modular protective structure on continuous miners against coal burst hazards
Publisher: SAGE Publications
Date: 10-02-2022
DOI: 10.1177/20414196211069574
Abstract: As mining progresses into deep ore deposits in Australia, geo-hazards such as coal burst and outbursts are becoming a major concern for mine workers. The occurrence of geo-hazards involved the ejection of coal lumps and sometimes large volumes of hazardous gases such as methane and carbon dioxide. Whilst it is extremely important to de-stress and de-gas the seam and adjacent strata before roadway development and install competent support systems such as steel mesh and bolt, the last line of protection will be the installation of a protective canopy on the Continuous Miner (CM), which is typically used for roadway developments, to shield mine workers from these deadly dynamic impacts of coal and rock resulting from a burst or outburst. This paper aims to introduce the design, manufacture and testing of an innovative modular protective structure on the CM in underground coal mines. The developed protective system can be easily assembled in the underground mining environment and provide a high level of protection against flying debris hazards in the event of a coal burst. The extensive experimental program and numerical simulations have confirmed the high performance of the protective system against high-speed impact loading by single and multiple coal rocks and projectiles.
Composite railway sleepers - Recent developments, challenges and future prospects
Publisher: Elsevier BV
Date: 12-2015
Flexural behaviour of GFRP reinforced high strength and ultra high strength concrete beams
Publisher: Elsevier BV
Date: 2017
NONLINEAR TRANSIENT ANALYSIS OF A RAILWAY CONCRETE SLEEPER IN A TRACK SYSTEM
Publisher: World Scientific Pub Co Pte Lt
Date: 09-2008
DOI: 10.1142/S0219455408002776
Abstract: Railway sleepers in a track system are usually subjected to a wide range of loading conditions. A critical type of loading condition that causes cracking in the railway concrete sleepers is the dynamic transient wheel force. The transient wheel forces are often due to wheel or rail abnormalities. This paper presents a dynamic finite element model of a railway concrete sleeper in a track system, aimed at raising the consideration of dynamic effects in sleeper design. The railway concrete sleeper is modeled using the beam-on-elastic-foundation theory. Since in the actual tracks the ballast underneath does not provide any tensile resistance, the finite beam elements employed in this investigation take into account the bending and shear deformations, together with the tensionless nature of the elastic support. This paper places emphasis on the effect of the transient periods on the flexural responses of railway sleepers in track systems. Using the robust finite element software STRAND7, the finite element model of the railway concrete sleeper was previously established and validated against experimental data by the authors. The numerical analyses present the ratio between the dynamic and the static bending moment resultants, the dynamic magnification factor, of the railway concrete sleeper under different sinusoidal pulse durations.
Response of Foam- and Concrete-Filled Square Steel Tubes under Low-Velocity Impact Loading
Publisher: American Society of Civil Engineers (ASCE)
Date: 10-2011
Experimental study on damage magnification effect of lightweight auxetic honeycomb protective panels under close-in blast loads
Publisher: Elsevier BV
Date: 09-2022
Digital Twins for Managing Railway Bridge Maintenance, Resilience, and Climate Change Adaptation
Publisher: MDPI AG
Date: 26-12-2022
DOI: 10.3390/S23010252
Abstract: Innovative digital twins (DTs) that allow engineers to visualise, share information, and monitor the condition during operation is necessary to optimise railway construction and maintenance. Building Information Modelling (BIM) is an approach for creating and managing an inventive 3D model simulating digital information that is useful to project management, monitoring and operation of a specific asset during the whole life cycle assessment (LCA). BIM application can help to provide an efficient cost management and time schedule and reduce the project delivery time throughout the whole life cycle of the project. In this study, an innovative DT has been developed using BIM integration through a life cycle analysis. Minnamurra Railway Bridge (MRB), Australia, has been chosen as a real-world use case to demonstrate the extended application of BIM (i.e., the DT) to enhance the operation, maintenance and asset management to improve the sustainability and resilience of the railway bridge. Moreover, the DT has been exploited to determine GHG emissions and cost consumption through the integration of BIM. This study demonstrates the feasibility of DT technology for railway maintenance and resilience optimisation. It also generates a virtual collaboration for co-simulations and co-creation of values across stakeholders participating in construction, operation and maintenance, and enhancing a reduction in costs and GHG emission.
Breach diameter analysis of concrete panels subjected to contact charge detonations
Publisher: Elsevier BV
Date: 10-2018
Greener and Leaner—Unleashing Capacity of Railroad Concrete Ties via Limit States Concept
Publisher: American Society of Civil Engineers (ASCE)
Date: 04-2011
Numerical simulation and validation of impact response of axially-restrained steel–concrete–steel sandwich panels
Publisher: Elsevier BV
Date: 12-2012
Explosive testing and modelling of square tubular steel columns for near-field detonations
Publisher: Elsevier BV
Date: 10-2014
Machine Learning Based Design of Railway Prestressed Concrete Sleepers
Publisher: MDPI AG
Date: 13-10-2022
DOI: 10.3390/APP122010311
Abstract: The state-of-the-art design methods for railway prestressed concrete sleepers are currently based on the quasi-static stresses resulting from a simplification of dynamic wheel loads, and subsequently the quasi-static responses of concrete sleepers. This method has been widely used in practices to overcome the complexity of dynamic analysis and testing. A single load factor (or called dynamic impact factor) for a partial safety-factored design (or k factors for the test criteria) is commonly used to crudely account for dynamic train–track interactions over different levels of track irregularities. The dynamic impact factors for either design or testing are usually obtained from either (i) railway infrastructure managers (i.e., in EN 13230), or (ii) prescribed standardised factors (i.e., AS 1085.14, AREMA Chapter 30, JSA—JIS E 1201). The existing design concepts for prestressed concrete sleepers using either (i) an allowable stress design or (ii) the limit state design method require many iterations for calculations and optimisations. The design process to achieve optimal products suitable for track, operational, and environmental parameters is, thus, very time-consuming. On this ground, this study investigates the potential capability of machine learning (ML) to learn from large amounts of design data sets and then to facilitate the design and capacity prediction of railway prestressed concrete sleepers. Three ML algorithms are developed, namely deep learning, Bayesian Neural Network, and random forest. Through a combination of hand-calculated design data, industry design data, and experimental investigations in compliance with EN 13230, over 3000 sets of design data have been collected. These data sets are used to assimilate a comprehensive database for machine learning. Four indicators, namely mean squared error (MSE), root-mean-square error (RMSE), mean absolute error (MAE), and R2 are used to benchmark the accuracy and precision of machine learning models. Our results reveal that the random forest algorithm offers the best performance. The values of MSE, RMSE, MAE, and R2 are 0.54, 0.74, 0.25, and 0.99, respectively. Note that the Bayesian neural network also performs very well. In contrast, the deep learning algorithm performs worse than the others. The insight demonstrates machine learning’s capability to aid in the design of railway prestressed concrete sleepers, to satisfy both serviceability and ultimate limit states
An Alternative Rail Pad Tester for Measuring Dynamic Properties of Rail Pads Under Large Preloads
Publisher: Springer Science and Business Media LLC
Date: 13-06-2007
Modelling blast loads on buildings in complex city geometries
Publisher: Elsevier BV
Date: 10-2005
Progressive failure of prestressed concrete sleepers under multiple high-intensity impact loads
Publisher: Elsevier BV
Date: 10-2009
Enhancing Toughness of Medium-Density Fiberboard by Mimicking Nacreous Structures through Advanced Manufacturing Techniques
Publisher: American Society of Civil Engineers (ASCE)
Date: 03-2020
Impact analyses for negative flexural responses (hogging) in railway prestressed concrete sleepers
Publisher: IOP Publishing
Date: 09-2016
Impact and close-in blast response of auxetic honeycomb-cored sandwich panels: Experimental tests and numerical simulations
Publisher: Elsevier BV
Date: 11-2017
Transparency Pays? Evaluating the Effects of the Freedom of Information Laws on Perceived Government Corruption
Publisher: Informa UK Limited
Date: 25-05-2017
Developing coal burst propensity index method for Australian coal mines
Publisher: Elsevier BV
Date: 09-2018
Predicting the effectiveness of blast wall barriers using neural networks
Publisher: Elsevier BV
Date: 12-2007
Special Issue “Extreme Sciences and Engineering”
Publisher: MDPI AG
Date: 12-11-2021
DOI: 10.3390/APP112210654
Abstract: Due to uncertainties stemming from climate change, natural and man-made disasters, and extreme events, unexpected disruptions in the operation of our countries’ infrastructure may put the functioning of our societies and their economies at risk [...]
Field trials for dynamic characteristics of railway track and its components using impact excitation technique
Publisher: Elsevier BV
Date: 10-2007
The response of axially restrained non-composite steel–concrete–steel sandwich panels due to large impact loading
Publisher: Elsevier BV
Date: 04-2013
Experimental and numerical investigation of high-yield grout ore pass plugs to resist impact loads
Publisher: Elsevier BV
Date: 09-2014
Dynamic flexural influence on a railway concrete sleeper in track system due to a single wheel impact
Publisher: Elsevier BV
Date: 04-2009
Experimental load rating of aged railway concrete sleepers
Publisher: Elsevier BV
Date: 10-2014
Parametric study on cement treated aggregate panel under impact load
Publisher: Springer Science and Business Media LLC
Date: 02-2018
Determination of Prestressing Force in Railway Concrete Sleepers Using Dynamic Relaxation Technique
Publisher: American Society of Civil Engineers (ASCE)
Date: 10-2015
Stress propagation and debonding effects in impedance-graded multi-metallic systems under impact loading
Publisher: SAGE Publications
Date: 12-05-2021
Abstract: This article investigates the performance of an impedance-graded multi-metallic system. Material combinations of steel–titanium, steel–aluminium and steel–titanium–aluminium are compared against a monolithic steel configuration. The experiments were carried out using a single-stage gas gun, where the target specimens consisted of these material configurations. The targets were subjected to the impact of an aluminium flyer at a velocity of 180 m/s, where elastic waves were expected to propagate through the target. The free surface velocity of the final material in the target was measured and these readings were used to quantify the stresses in the materials. These stress results were compared with the output from two-dimensional axisymmetric numerical models and theoretical equations. The findings of this study indicated that a target configuration with gradual impedance reduction could minimize the magnitudes of both compressive and tensile stresses in the materials, where the latter is critical towards preventing debonding in a multi-material system.
Enhancement of blast wave parameters due to shock focusing from multiple simultaneously detonated charges
Publisher: SAGE Publications
Date: 24-07-2021
DOI: 10.1177/20414196211033310
Abstract: With the increase of terrorist attacks over the past decades, many engineering societies have started issuing design guides to calculate blast loads on structures. While such guides can be successfully used to assess blast loads due to single detonations, the effects of multiple detonations are often overlooked. In this research, the enhancement in blast parameters resulting from simultaneously detonating multiple charges is investigated, emphasising the interaction of blast waves with narrow targets. A parametric CFD study using the finite volume code Viper::Blast was performed where the number of charges, their arrangement, and the scaled stand-off distances were changed. It is found that, when detonated simultaneously, multiple charges return much higher pressure and impulse values compared to an equivalent single charge. Moreover, an arced arrangement of multiple charges is more efficient than a flat arrangement in enhancing blast wave parameters. Such enhancement is beneficial in scenarios involving demolition. Approximate methods to compute blast wave parameters from multiple simultaneously detonated spherical charges are presented in this study, where pressure and impulse from multiple charges can be computed by only knowing the parameters resulting from an equivalent single charge.
The development and ballistic performance of protective steel-concrete composite barriers against hypervelocity impacts by explosively formed projectiles
Publisher: Elsevier BV
Date: 2019
What drives FDI policy liberalization? An empirical investigation
Publisher: Elsevier BV
Date: 11-2014
An Experimental Investigation of the Performance of Non-Composite Steel-Concrete-Steel Protective Panels under Large Impact Loading
Publisher: SAGE Publications
Date: 07-2013
DOI: 10.1260/1369-4332.16.7.1163
Abstract: In conventional steel-concrete-steel (SCS) construction, the external steel plates are connected to the concrete infill by welded shear connectors. This paper describes an experimental programme in which the response of axially restrained non-composite (without shear connectors) SCS protective panels subject to impulsive loading was studied. A comprehensive parametric study was carried out to investigate the effects of different types of infill materials, amount of impact energy, and the bond between the concrete core and steel faceplates, on the performance of the protective panels. The experimental results showed that the panels developed high load-carrying capacity through the tensile membrane resistance of the steel faceplates at large deformation. The panels demonstrated a highly ductile response and were able to sustain large deformation up to 18 degrees end rotation without collapse. The high strength and high ductility characteristics of these SCS panels make them an economical alternative to the existing protective barrier structures.
EXPERIMENTAL SIMULATION OF THE RAILWAY BALLAST BY RESILIENT MATERIALS AND ITS VERIFICATION BY MODAL TESTING
Publisher: Springer Science and Business Media LLC
Date: 07-2008
Impact fatigue responses of pre-stressed concrete sleepers in railway track systems
Publisher: Informa UK Limited
Date: 02-2009
Reliability-based conversion of a structural design code for railway prestressed concrete sleepers
Publisher: SAGE Publications
Date: 12-09-2011
Abstract: Ballasted railway track is very suitable for heavy-rail networks because of its many superior advantages in design, construction, short- and long-term maintenance, sustainability, and life cycle cost. An important part of the railway track system, which distributes the wheel load to the formation, is the railway sleeper. Improved knowledge has raised concerns about design techniques for prestressed concrete (PC) sleepers. Most current design codes for these rely on allowable stresses and material strength reductions. However, premature cracking of PC sleepers has been found in railway tracks. The major cause of cracking is the infrequent but high-magnitude wheel loads produced by the small percentage of irregular wheels or rail-head surface defects both these are crudely accounted for in the allowable stress design method by a single load factor. The current design philosophy, outlined in Australian Standard AS1085.14, is based on the assessment of permissible stresses resulting from quasi-static wheel loads and essentially the static response of PC sleepers. To shift the conventional methodology to a more rational design method that involves a more realistic dynamic response of PC sleepers and performance-based design methodology, comprehensive studies of the loading conditions, the dynamic response, and the dynamic resistance of PC sleepers have been conducted. This collaborative research between several Australian universities has addressed such important issues as the spectrum and the litudes of dynamic forces applied to the railway track, evaluation of the reserve capacity of typical PC sleepers designed to AS 1085.14, and the development of a new limit states design concept. This article presents the results of the extensive analytical and experimental investigations aimed at predicting wheel impact loads at different return periods (based on field data from impact detectors), together with an experimental investigation of the ultimate impact resistance of PC sleepers required by the limit states design approach. It highlights the reliability approach and rationales associated with the development of limit states and presents guidelines pertaining to conversion of AS 1085.14 to a limit states design format. The reliability concept provides design flexibility and broadens the design principle, so that any operational condition could be catered for optimally in the design.
Effect of a large asymmetrical wheel burden on flexural response and failure of railway concrete sleepers in track systems
Publisher: Elsevier BV
Date: 12-2008
Investigation of free vibrations of voided concrete sleepers in railway track system
Publisher: SAGE Publications
Date: 07-2007
Abstract: Concrete railway sleepers in ballasted track are laid on ballast and subgrade supporting systems. Full contact between sleepers and ballast is typically assumed for analysis and design purposes. Often, voids and pockets in the sleeper/ballast contact interface form between sleepers and the ballast underneath that could cause problems to both the sleepers and the track system as a whole. The current paper investigates the effects of ballast voids and pockets on free vibration response characteristics of in situ railway concrete sleepers. Finite-element modelling was employed to develop a dynamic model of the railway track incorporating concrete sleepers. This model includes the dynamic interaction of sleepers and ballast as part of the free vibration analyses of the in situ railway concrete sleepers. Several patterns of voids and pockets underneath railway sleepers were studied. The emphasis was placed on partial and full interaction between sleepers and ballast. The information on the vertical vibration modes provides an important insight into the dynamic response of concrete railway sleepers in different void-and-pocket configurations.
Dynamic crushing response of novel re-entrant circular auxetic honeycombs: Numerical simulation and theoretical analysis
Publisher: Elsevier BV
Date: 05-2022
Impact capacity of railway prestressed concrete sleepers
Publisher: Elsevier BV
Date: 07-2009
Performance and dynamic behaviour of FRP strengthened CFST members subjected to lateral impact
Publisher: Elsevier BV
Date: 09-2017
Static and dynamic behaviours of railway prestressed concrete sleepers with longitudinal through hole
Publisher: IOP Publishing
Date: 10-2017
Do freedom of information laws improve bureaucratic efficiency? An empirical investigation
Publisher: Oxford University Press (OUP)
Date: 05-04-2016
DOI: 10.1093/OEP/GPW008
A review of loading conditions for railway track structures due to train and track vertical interaction
Publisher: Hindawi Limited
Date: 03-2008
DOI: 10.1002/STC.227
Structural Behaviours of Railway Prestressed Concrete Sleepers (Crossties) With Hole and Web Openings
Publisher: Elsevier BV
Date: 2016
Experimental Investigation on Dynamic Railway Sleeper/Ballast Interaction
Publisher: Springer Science and Business Media LLC
Date: 02-2006
Prediction of airblast loads in complex environments using artificial neural networks
Publisher: WIT Press
Date: 26-06-2006
DOI: 10.2495/SU060271
Experimental investigation of the behaviour of concrete beams reinforced with GFRP bars under static and impact loading
Publisher: Elsevier BV
Date: 04-2016
EFFECT OF IMPROPER BALLAST PACKING/TAMPING ON DYNAMIC BEHAVIORS OF ON-TRACK RAILWAY CONCRETE SLEEPER
Publisher: World Scientific Pub Co Pte Lt
Date: 03-2007
DOI: 10.1142/S0219455407002174
Abstract: Ballasted railway tracks are impaired due to either normal or abnormal operations. One of the problems is the differential settlements along the track. Clearly, there is the need to maintain periodically the track substructures by means of ballast packing/t ing. Inappropriate conducts result in the nonlinear distributions of support stiffness. This study firstly demonstrates the effects of improper ballast packing/t ing on the free vibration behaviors of in situ railway concrete sleepers. The two-dimensional finite element modeling of an in situ concrete sleeper was employed in the parametric studies. This model takes into account the coupled flexural-and-shear deformations of concrete sleepers, elastic displacements of fastening system, and nonlinear dynamic interaction between the sleeper and ballast support. Dynamic interaction between sleepers and ballast was investigated based on the nonlinear distribution of ballast support stiffness underneath the sleeper. Effects of both symmetrical and asymmetrical stiffness distributions on dynamic behaviors of the local in situ concrete sleeper were also highlighted.
Vibration Attenuation at Rail Joints through under Sleeper Pads
Publisher: Elsevier BV
Date: 2017
Briefing: Limit states design of railway concrete sleepers
Publisher: Thomas Telford Ltd.
Date: 05-2012
DOI: 10.1680/TRAN.9.00050
Abstract: Recently updated information has raised a concern over not only the existing cost-ineffective design method but also the unrealistic analysis mode of railroad prestressed concrete sleepers. Because of the deficient knowledge in the past, railway civil engineers have been mostly aware of the over-conservative design methods for structural components in any railway track, which rely on allowable stresses and material strength reductions. Based on a number of proven experiments and field data, it is believed that the concrete sleepers which complied with the allowable stress concept possess unduly untapped fracture toughness. A collaborative research project run by the Australian Cooperative Research Centre for Railway Engineering and Technologies (RailCRC) was initiated to ascertain the reserved capacity of Australian railway prestressed concrete sleepers designed using the existing design code. The findings have led to the development of a new limit states design concept. This briefing highlights the conventional and the new limit states design philosophies and their implication to both the railway and the public community.
Transverse impact resistance of hollow and concrete filled stainless steel columns
Publisher: Elsevier BV
Date: 03-2013
Numerical Investigation of the Response of Protective Barrier under Blast Loading
Publisher: Trans Tech Publications, Ltd.
Date: 06-2014
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMM.567.440
Abstract: Non-composite steel-concrete-steel panels develop high load-carrying capacity through the tensile membrane resistance of the steel faceplates at large displacement. The response of a full-scale barrier structure composed of the non-composite SCS panels and steel posts under various blast loading scenarios was investigated using non-linear finite element software LS-Dyna. The simulation results showed that the barrier was able to withstand very large blast energy. It can be concluded that non-composite SCS panels can provide an attractive solution to expedite construction of high-performance protective barriers to resist extreme blast loadings.
Reprint of: Experimental investigation and simplified modeling of response of steel plates subjected to close-in blast loading from spherical liquid explosive charges
Publisher: Elsevier BV
Date: 07-2017
Dynamic Performance of Concrete Turnout Bearers and Sleepers in Railway Switches and Crossings
Publisher: ASTM International
Date: 03-2018
DOI: 10.1520/ACEM20170103
Explosive Breaching of Walls with Contact Charges: Theory and Applications
Publisher: SAGE Publications
Date: 12-2015
DOI: 10.1260/2041-4196.6.4.629
Abstract: Breaching activities are required for military operations in urban environment and for firefighters in emergency situations for saving lives. Explosive wall breaching is a key capability in military operations in urban terrain environments where the close proximity of urban structures significantly restricts the use of large demolition charges. Explosive breaching is also used by special operations groups as a means to gain entry into a structure where conventional breaching methods are not sufficient or the emergency situation requires immediate entry to save lives. This paper develops an analytical model for the explosive breaching of protective targets such as concrete and masonry walls. It provides simple analytical models based on the principles of blast physics and the conservation laws for the characteristics of contact charges required to produce a wall breach of the required shape and size. The model is validated using the experimental data. An illustrative ex le is included to demonstrate the model's ability to predict the size of a breach hole in a thick masonry wall.
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