Infrastructure Engineering - Research Publications

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    A macro-element model for predicting the combined load behaviour of spudcan foundations in clay overlying sand
    Wang, Y ; Cassidy, MJ ; Bienen, B (Thomas Telford Ltd., 2021-10-26)
    A macro-element model for predicting the load–displacement behaviour of a spudcan foundation in clay overlying sand when subjected to combined vertical, horizontal and moment loading is introduced. Observations from detailed drum centrifuge tests that measured the effect of the underlying sand layer on the foundation behaviour are combined with finite-element results and theoretical developments to derive the components of the model. The yield surface defined by the centrifuge test results suggests that as the spudcan nears the underlying sand layer, the absolute horizontal capacity remains relatively constant, while the vertical and moment capacities increase at approximately the same normalised rate. The model is demonstrated to accurately predict foundation behaviour by retrospectively simulating the experimental results. This macro-element model has the advantage that it can be integrated into the structural analyses of jack-up platforms required for site-specific assessments.
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    Feasibility and performance analysis of hybrid ground source heat pump systems in fourteen cities
    Weeratunge, H ; Aditya, GR ; Dunstall, S ; de Hoog, J ; Narsilio, G ; Halgamuge, S (PERGAMON-ELSEVIER SCIENCE LTD, 2021-11-01)
    Ground source heat pump systems (GSHP) for residential building heating, cooling, and hot water are highly energy efficient but capital intensive when sized for peak demands. The use of supplemental sources of energy with GSHP systems enables improved life-cycle economics through the reduction in the size and cost of the GSHP components. This paper investigates the life-cycle economics of hybrid solar-assisted ground source heat pump systems (SAGSHP) using simulations validated from field data. The economics and optimal sizing of SAGSHP systems for heating dominant climates in four locations in Australia and ten locations elsewhere are evaluated in order to explore the suitability and relative merits of SAGSHP systems in a range of heating dominant climates. In locations having high or moderate levels of solar irradiation, high electricity prices, and high or moderate gas prices, SAGSHP systems are shown to have the lowest life cycle cost amongst alternatives, with predicted savings of up to 30%.
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    Innovative composite structural systems for modular tall buildings
    Thai, HT ; Knobloch, M ; Kuhlmann, U ; Kurz, W ; Schafer, M (https://www.compositeconstructionix.com/, 2021)
    Modular or offsite construction is believed to shape the future of the construction industry as it possesses significant benefits over traditional onsite construction methods. However, most of its application are limited to steel or concrete buildings. Although steel-concrete composite structural system has many merits over the steel and concrete systems, its application in modular buildings is very limited. This paper explores recent developments of composite systems for modular high-rise buildings. They include modular units for resisting vertical gravity loads and lateral structural systems for resisting horizontal forces from wind and earthquake loadings and progressive collapse due to accidental loads such as fire, explosions and impact. Various inter-module joining methods developed in the literature will also be reviewed. Finally, a case study of the most efficient connection is presented to explore its applicability to high-rise modular buildings.
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    Privacy- and context-aware release of trajectory data
    Naghizade, E ; Kulik, L ; Tanin, E ; Bailey, J (ACM, 2020-03)
    The availability of large-scale spatio-temporal datasets along with the advancements in analytical models and tools have created a unique opportunity to create valuable insights into managing key areas of society from transportation and urban planning to epidemiology and natural disasters management. This has encouraged the practice of releasing/publishing trajectory datasets among data owners. However, an ill-informed publication of such rich datasets may have serious privacy implications for individuals. Balancing privacy and utility, as a major goal in the data exchange process, is challenging due to the richness of spatio-temporal datasets. In this article, we focus on an individual's stops as the most sensitive part of the trajectory and aim to preserve them through spatio-temporal perturbation. We model a trajectory as a sequence of stops and moves and propose an efficient algorithm that either substitutes sensitive stop points of a trajectory with moves from the same trajectory or introduces a minimal detour if no safe Point of Interest (POI) can be found on the same route. This hinders the amount of unnecessary distortion, since the footprint of the original trajectory is preserved as much as possible. Our experiments shows that our method balances user privacy and data utility: It protects privacy through preventing an adversary from making inferences about sensitive stops while maintaining a high level of similarity to the original dataset.
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    Innovative composite structural systems for modular tall buildings
    Thai, HT ; Knobloch, M ; Kuhlmann, U ; Kurz, W ; Schafer, M (https://www.compositeconstructionix.com/, 2021)
    Modular or offsite construction is believed to shape the future of the construction industry as it possesses significant benefits over traditional onsite construction methods. However, most of its application are limited to steel or concrete buildings. Although steel-concrete composite structural system has many merits over the steel and concrete systems, its application in modular buildings is very limited. This paper explores recent developments of composite systems for modular high-rise buildings. They include modular units for resisting vertical gravity loads and lateral structural systems for resisting horizontal forces from wind and earthquake loadings and progressive collapse due to accidental loads such as fire, explosions and impact. Various inter-module joining methods developed in the literature will also be reviewed. Finally, a case study of the most efficient connection is presented to explore its applicability to high-rise modular buildings.
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    Do digital natives telework more than digital immigrants?
    Cheng, Y-T ; Sauri Lavieri, P ; Astroza, S (ATRF, 2021)
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    Performance of a wheat yield prediction model and factors influencing the performance: A review and meta-analysis
    Hao, S ; Ryu, D ; Western, A ; Perry, E ; Bogena, H ; Franssen, HJH (ELSEVIER SCI LTD, 2021-12)
    CONTEXT: Process-based crop models provide ways to predict crop growth, evaluate environmental impacts on crops, test various crop management options, and guide crop breeding. They can be used to explore options for mitigating climate change impacts when combined with climate projections and explore mitigation of environmental impacts of production. The Agricultural Production Systems SIMulator (APSIM) is a widely adopted crop model that offers modules for simulation of various crops, soil processes, climate, and grazing within a modelling system that enables robust addition of new components. OBJECTIVE: This study uses APSIM Classic-Wheat as an example to examine yield prediction accuracy of biophysically based crop yield modelling and to analyse the factors influencing the model performance. METHODS: We analysed yield prediction results of APSIM Classic-Wheat from 76 published studies across thirteen countries on four continents. In addition, a meta-database of modelled and observed yields from 30 studies was established and used to identify factors that influence yield prediction uncertainty. RESULTS AND CONCLUSIONS: Our analysis indicates that, with site-specific calibration, APSIM predicts yield with a root mean squared error (RMSE) smaller than 1 t/ha and a normalised RMSE (NRMSE) of about 28%, across a wide range of environmental conditions for independent evaluation periods. The results show increasing errors in yield with limited modelling information and adverse environmental conditions. Using soil hydraulic parameters derived from site-specific measurements and/or tuning cultivar parameters improves yield prediction accuracy: RMSE decreases from 1.25 t/ha to 0.64 t/ha and NRMSE from 32% to 14%. Lower model accuracy was found where APSIM overestimates yield under high water deficit condition and when it underestimates yield under nitrogen limitation. APSIM severely over-predicts yield when some abiotic stresses such as heatwaves and frost affect the crop growth. SIGNIFICANCE: This paper uses APSIM-Wheat as an example to provide perspectives on crop model yield prediction performance under different conditions covering a wide spectrum of management practices, and environments. The findings deepen the understanding of model uncertainty associated with different calibration processes or under various stressed conditions. The results also indicate the need to improve the model's predictive skill by filling functional gaps in the wheat simulations and by assimilating external observations (e.g., biomass information estimated by remote sensing) to adjust the model simulation for stressed crops.
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    Integrating sustainability into higher education curricula
    Rajabifard, A ; Elisa, L ; Herath, N ; Hui, K ; Currie, G ; Kahalimoghadam, M (Engineers Australia, 2021)
    Education has been widely recognised as a key instrument to achieve sustainability. Integrating sustainability knowledge, skills and values are considered paramount to enable individuals to contribute to sustainable development. The paper presents a pilot study conducted at the University of Melbourne to investigate the links between the subjects offered by the University and sustainability. The pilot study is a part of the Sustainability in the Curriculum program, which addresses the Sustainability Plan Teaching and Learning Target 1, aimed to incorporate sustainability knowledge and values in the University's curricula. The 17 Sustainability Development Goals have been used as a framework to measure how well the curricula are linked to sustainability. A study first undertaken to establish the link between subjects and the Sustainability Development Goals is presented. The study involved data collection through published literature on Sustainable Development Goals and the University's subject handbook, followed by a survey involving the subject coordinators. The findings of the study show that the strength of linkages between subjects with sustainability varies, highlighting the challenge in some technical subjects in linking their contents with sustainability. Approaches adopted in the Faculty of Engineering and Information Technology in embedding sustainability in the curriculum are presented with some examples and discussions for the next steps.
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    Multimodal relationships: shared and automated vehicles and high-capacity public transit
    Freemark, Y ; Nassir, N ; Zhao, J ; Ata, K ; Susan, S (The Institution of Engineering and Technology, 2021-12-01)
    Shared mobility is gaining increasing attention in private and public sectors. Serving as a source of information on how best to shape shared vehicle systems of the future, this book contributes knowledge on key facets of shared mobility.
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    A Bayesian approach to understanding the key factors influencing temporal variability in stream water quality: a case study in the Great Barrier Reef catchments
    Liu, S ; Ryu, D ; Webb, JA ; Lintern, A ; Guo, D ; Waters, D ; Western, AW ( 2021-01-12)
    Abstract. Stream water quality is highly variable both across space and time. Water quality monitoring programs have collected a large amount of data that provide a good basis to investigate the key drivers of spatial and temporal variability. Event-based water quality monitoring data in the Great Barrier Reef catchments in northern Australia provides an opportunity to further our understanding of water quality dynamics in sub-tropical and tropical regions. This study investigated nine water quality constituents, including sediments, nutrients and salinity, with the aim of: 1) identifying the influential environmental drivers of temporal variation in flow event concentrations; and 2) developing a modelling framework to predict the temporal variation in water quality at multiple sites simultaneously. This study used a hierarchical Bayesian model averaging framework to explore the relationship between event concentration and catchment-scale environmental variables (e.g., runoff, rainfall and groundcover conditions). Key factors affecting the temporal changes in water quality varied among constituent concentrations, as well as between catchments. Catchment rainfall and runoff affected in-stream particulate constituents, while catchment wetness and vegetation cover had more impact on dissolved nutrient concentration and salinity. In addition, in large dry catchments, antecedent catchment soil moisture and vegetation had a large influence on dissolved nutrients, which highlights the important effect of catchment hydrological connectivity on pollutant mobilisation and delivery.