Infrastructure Engineering - Research Publications
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ItemDevelopment and performance evaluation of large-scale auxetic protective systems for localised impulsive loads(Multi-Science Publishing, 2019-09-01)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.
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ItemEffective use of offsite manufacturing for public infrastructure projects in Australia(ICE Publishing, 2019)Prefabrication and offsite manufacturing have featured in various forms in an in-situ based construction industry for many decades. Scarcity of both human and material resources is challenging the future of traditional construction practices. Due to its many benefits such as speed of project delivery, minimum work on site, minimised construction waste and higher quality assurance, offsite manufacturing is gradually evolving into an essential technology in the construction industry. As a result of re-cent government initiatives, Australia is seeing a considerable increase in the use of offsite manufacturing and prefabricated modular technologies in delivering public infrastructure projects such as schools, healthcare facilities, and public transport facilities. Such projects are ably supported by academic research collaborating with the industry to ensure that the outcomes keep improving to achieve the highest quality and functionality. This paper discusses how multidisciplinary research addresses issues such as structural performance, construction technology, design for manufacturing and assembly and indoor environ-mental quality for the delivery of such public infrastructure projects. These projects have set an example in how offsite manufacturing supported by academic research can be beneficial for effectively delivering the greater good to the society.
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ItemNo Preview AvailableDuctility Design of Reinforced Very-High Strength Concrete Columns (100–150 MPa) Using Curvature and Energy-Based Ductility Indices(Springer Science and Business Media LLC, 2019-12-01)The paper aims to develop theoretical expressions for the ductility design of very-high strength concrete (VHSC) (> 100 MPa) columns using curvature and a new flexural energy-based ductility approach. Eventually, the study aims to evaluates the feasibility of VHSC columns for different ductility classes, considering the limitation of providing a higher volume of transverse reinforcement due to possible steel congestion in the construction phase. An analytical program based on the experimental stress–strain relationship of confined VHSC, which is validated using experimental programs on VHSC columns, is used to evaluate the ductility of VHSC columns for different parameters such as axial load ratio, confinement pressure, longitudinal steel ratio, yield strength of transverse steel, cover area and compressive strength of concrete. The theoretical curvature ductility and flexural rotation-based energy ductility of 3200 rectangular columns were evaluated using the analytical program. Using curvature ductility and the new flexural rotation-based energy ductility for different parameters, a regression analysis is carried out to develop expressions for the ductility design of VHSC columns up to 150 MPa. Using the new definition of energy-based ductility, a new expression is developed for limited ductility design of VHSC; and it is concluded that the new approach reduces the required amount of steel confinement due to an increase in the energy ductility of VHSC at higher axial load ratios and higher strengths. The studies show that reinforced VHSC can be used for structures with nominal ductility demands.
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ItemFire resistance of a prefabricated bushfire bunker using aerated concrete panels(Elsevier, 2018-06-20)Prefabricated lightweight aerated concrete (PLAC) panels provide low thermal conductivity, potentially high stiffness-to-weight ratios, cost-effective material and structural systems and rapid modular construction. These panels can be utilised as floor slabs or external walls for various applications in building construction. The fire performance of the PLAC panel is examined in this work for a particular case, namely a prefabricated emergency bushfire shelter, which is one of the key applications of PLAC panels. Since, bushfires have unique heating curves, standardised tests are not useful and the system needs to be tested in a manner such that the heat flux of an actual bush fire can be reproduced. In this study, the fire performance enhancement of dual-skin bushfire bunkers, which are comprised of lightweight concrete and base metal thickness (BMT) steel, are examined experimentally and validated numerically. The Speedpanel PLAC modular panel explored in this work is a lightweight wall system primarily used for acoustic and thermal insulation purposes. Burning experimental studies of a single panel and dual-skin bunkers are carried out on a full scale. The experimental results are compared with fire safety codes for building materials to identify the key areas for improvements. A fire dynamic numerical model has been developed in this work using the Fire Dynamics Simulator (FDS) to simulate the burning process of PLAC structures. Numerical results of heat production are presented in comparison with experimental observations for validating the computational model. The proposed numerical model is used to predict the fire performance of a dual-skin bushfire bunker, demonstrating the need to have at least two PLAC layers to ensure fire safety compliance.
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ItemAn optimum construction strategy for multi-story residential prefabricated modular buildings(ZEMCH Network, 2018-01-29)Prefabrication is recognised as the way forward in building construction by the industry as it delivers quality yet affordable mass customisable houses faster than traditional on-site construction. The prefabrication of multi-story buildings transforms traditional construction into off-site manufacturing of repetitive components. Currently there are three main structural systems being adopted for modular multi-story buildings; 1) Building with a rigid in-situ central core to which the modules are connected, 2) A podium structure which acts as a base where modules are placed on top of it, 3) Fully modular structure with strategically placed load bearing modules. Current investigations on these systems focus on improving their benefits such as construction time, cost, safety and quality based on one variable at a time. However, there is a lack of studies with a holistic approach to identify the optimum structural system. This paper aims to define an Optimum Modular System Index (OMI) which will be based upon three main indices; Assembly cost penalty Index (ACPI), Onsite handling cost penalty Index (HCPI) and Concrete cost penalty Index (CCPI). Determination of OMI is expected to provide a framework to identify the optimum construction system for multi-story residential prefabricated modular buildings.