Infrastructure Engineering - Research Publications
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ItemAggregate interlock in fractured concrete mesoscale models: a novel finite element modelling approach(SPRINGERNATURE, 2022-07-17)Abstract Aggregate interlock is a stress transfer mechanism in cracked concrete. After concrete cracks under tensile loading, crack interfaces can experience significant slip deformation due to the applied crack kinematics. Upon rising slip along crack interfaces, aggregate interlock stresses are generated which transfer shear stress and normal stress. Many experimental programmes and analytical expressions have been developed for several decades. However, a finite element model considering realistic crack surfaces was still not developed. The complexity of developing a FE model lies due to the mesoscopic nature of the problem. In this study, concrete mesoscale models were employed to generate realistic cracked concrete surfaces. Uniaxial tensile fracture propagation in concrete mesoscale models were achieved using Zero-thickness cohesive elements approach. Once cracked concrete FE models are developed, validation of the proposed FE models was conducted against two experimental campaigns. The study comprises the evaluation of the surface roughness index of the cracked concrete surfaces. The FE model predicts secondary cracking under low initial crack widths and mixed mode angles. FE predictions were further compared with Walraven’s simplified formulae, Bažant’s rough crack model, Cavagnis’s aggregate interlock formulae and contact density model and consistence agreement was observed. Finally, strengths and weaknesses of the proposed FE modelling approach for aggregate interlock was discussed and further implementations were also highlighted.
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ItemNo Preview AvailableUpcycling opportunities and potential markets for aluminium composite panels with polyethylene core (ACP-PE) cladding materials in Australia: A review(ELSEVIER SCI LTD, 2022-11-28)Many buildings worldwide have high fire-risk materials as part of their cladding. As governments in Australia strive to make buildings safer, it is expected that a large volume of end-of-life dangerous cladding will be replaced with safer materials. This high volume of hazardous materials might be upcycled into value-added products. This article presents a systematic market analysis and literature review in identifying current and potential uses for the raw materials used in hazardous ACP-PE cladding. The most promising areas were identified to be non-food-contact packaging (US$228 M p.a.), non-pressure pipes (US$30 M p.a.), footwear (US$5.29 M p.a.) and 3D printer filament (US$2.73 M p.a.)
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ItemAirborne and impact sound performance of modern lightweight timber buildings in the Australian construction industry(Elsevier BV, 2021-12)Timber usage in the Australian construction industry has significantly increased due to its strength, aesthetic properties and extended allowances recently introduced in building codes. However, issues with acoustic performance of lightweight timber buildings were reported due to their inherit product variability and varying construction methods. This article reviews the recent literature on the transmissions of impact and airborne sounds, flanking transmission of timber buildings, and the state of computer prediction tools with reference to the Australian practice. An in-depth analysis of issues and an objective discussion related to acoustic performance of timber buildings are presented. Timber is a lightweight material and shows low airborne sound resistance in low frequency range. Attenuation of sound transmission with addition of mass, layer isolation, different products like cross-laminated timber and prefabrication are discussed. Challenges in measuring sound transmissions and reproducibility of results in low frequency ranges are discussed. Well-defined measurement protocols and refined computer simulation methods are required. The serviceability design criteria for modern lightweight timber applications in Australia need to be re-evaluated in the area of impact generated sound. Developing computer tools to predict airborne and impact sound transmission in lightweight timber buildings is quite challenging as several components such as timber members and complex connections with varying stiffnesses are non-homogeneous by nature. Further, there is a lack of experimentally validated and computationally efficient tools to predict the sound transmission in timber buildings. Computer prediction tools need to be developed with a focus on mid-frequency transmission over flanks and low-frequency transmission of timber and prefabricated buildings.
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ItemOptimising the computational domain size in CFD simulations of tall buildings(Elsevier, 2021-04-01)Recently, there has been a growing interest in utilizing computational fluid dynamics (CFD) for wind resistant design of tall buildings. A key factor that influences the accuracy and computational expense of CFD simulations is the size of the computational domain. In this paper, the effect of the computational domain on CFD predictions of wind loads on tall buildings is investigated with a series of sensitivity studies. Four distinct sources of domain error are identified which include wind-blocking effects caused by short upstream length, flow recirculation due to insufficient downstream length, global venturi effects due to large blockage ratios, and local venturi effects caused by insufficient clearance between the building and top and lateral domain boundaries. Domains based on computational wind engineering guidelines are found to be overly conservative when applied to tall buildings, resulting in uneconomic grids with a large cell count. A framework for optimizing the computational domain is proposed which is based on monitoring sensitivity of key output metrics to variations in domain dimensions. The findings of this paper help inform modellers of potential issues when optimizing the computational domain size for tall building simulations.
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ItemImpact of atmospheric boundary layer inhomogeneity in CFD simulations of tall buildings(Elsevier BV, 2020-07)Recently, there has been a growing interest in utilizing computational fluid dynamics (CFD) for wind analysis of tall buildings. A key factor that influences the accuracy of CFD simulations in urban environments is the homogeneity of the atmospheric boundary layer (ABL). This paper aims to investigate solution inaccuracies in CFD simulations of tall buildings that are due to ABL inhomogeneity. The investigation involves two steps. In the first step, homogenous and inhomogeneous ABL conditions are generated in an empty computational domain by employing two different modelling approaches. In the second step, the homogenous and inhomogeneous conditions are each applied to an isolated tall building, and simulation results are compared to investigate impact of ABL inhomogeneity on wind load predictions. The study finds that ABL inhomogeneity can be a significant source of error and may compromise reliability of wind load predictions. The largest magnitude of inhomogeneity error occurred for pressure predictions on the windward building surface. Shortening the upstream domain length reduced inhomogeneity errors but increased errors due to wind-blocking effects. The study proposes a practical approach for detecting ABL inhomogeneity that is based on monitoring sensitivity of key output metrics to variations in upstream domain length.