Infrastructure Engineering - Research Publications
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ItemMulti-Criteria Analysis of a Developed Prefabricated Footing System on Reactive Soil Foundation(MDPI, 2021-11)The need for advancements in residential construction and the hazard induced by the shrink–swell reactive soil movement prompted the development of the prefabricated footing system of this study, which was assessed and compared to a conventional waffle raft using a multi-criteria analysis. The assessment evaluates the structural performance, cost efficiency, and sustainability using finite element modelling, life cycle cost analysis, and life cycle assessment, respectively. The structural performance of the developed prefabricated system was found to have reduced the deformation and cracking by approximately 40%. However, the cost, GHG emission, and embodied energy were higher in the prefabricated footing system due to the greater required amount of concrete and steel than that of the waffle raft. The cost difference between the two systems can be reduced to as low as 6% when prefabricated systems were installed in a highly reactive sites with large floor areas. The life cycle assessment further observed that the prefabricated footing systems consume up to 21% more energy and up to 18% more GHG emissions. These can significantly be compensated by reusing the developed prefabricated footing system, decreasing the GHG emission and energy consumption by 75–77% and 55–59% with respect to that of the waffle raft.
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ItemMicrostructural Investigation of High-Volume Fly Ash Composites Containing Nano-Calcium Silicate Hydrate Crystals(ASCE-AMER SOC CIVIL ENGINEERS, 2021-12-01)
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ItemNew normal remote communication for collaboration (presentation)( 2021-12-19)Presented at the 12th International Conference on Structural Engineering and construction Management (ICSECM) 2021, Kandy, Sri Lanka (17-19 December)
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ItemNo Preview AvailableFlexural Capacity Prediction Model For Steel Fibre-Reinforced Concrete Beams(SPRINGER, 2021-06-03)Abstract Steel fibre (SF) reinforcement has been shown to improve the ductility of high strength concrete (HSC), which is known to be brittle. Research conducted to date on steel fibre reinforced concrete and its effects have emphasised post-failure performance and cracking mechanism. The difficulty in predicting the behaviour of fibres is due to the randomly distributed nature of the material within the matrix leading to a probability distribution of results. Published literature has shown a benefit of adding steel fibres in terms of the ductility performance of structures. Clearly, there is a potential for such material as replacement of conventional steel reinforcement. This study proposes a theoretical model of evaluating the potential of using steel fibres as a replacement material to conventional steel reinforcement bars based on the case study, laboratory and theoretical methodologies. The compressive strength of the concrete at key dates, the effective fibre cross-sectional were measured, and a prediction model was created based on the measurement parameters. The use of four-point flexural testing, standard compressive testing and software image modelling provided the study with relevant data used to analyse and compare to the prediction. Greater ductility performance and toughness were observed with increased fibre volumes, confirming proposed predictions and conclusion drawn from published literature. No consistent or conclusive correlations between fibre volumes and the compressive strength of concrete were found. A relationship between fibre volumes and predicted moment capacities of steel fibre reinforced concrete beams was found based on the proposed theoretical flexural analysis method.
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ItemEngineering Performance of Concrete Incorporated with Recycled High-Density Polyethylene (HDPE)-A Systematic Review(MDPI, 2021-06)Incorporating recycled plastic waste in concrete manufacturing is one of the most ecologically and economically sustainable solutions for the rapid trends of annual plastic disposal and natural resource depletion worldwide. This paper comprehensively reviews the literature on engineering performance of recycled high-density polyethylene (HDPE) incorporated in concrete in the forms of aggregates or fiber or cementitious material. Optimum 28-days' compressive and flexural strength of HDPE fine aggregate concrete is observed at HDPE-10 and splitting tensile strength at HDPE-5 whereas for HDPE coarse aggregate concrete, within the range of 10% to 15% of HDPE incorporation and at HDPE-15, respectively. Similarly, 28-days' flexural and splitting tensile strength of HDPE fiber reinforced concrete is increased to an optimum of 4.9 MPa at HDPE-3 and 4.4 MPa at HDPE-3.5, respectively, and higher than the standard/plain concrete matrix (HDPE-0) in all HDPE inclusion levels. Hydrophobicity, smooth surface texture and non-reactivity of HDPE has resulted in weaker bonds between concrete matrix and HDPE and thereby reducing both mechanical and durability performances of HDPE concrete with the increase of HDPE. Overall, this is the first ever review to present and analyze the current state of the mechanical and durability performance of recycled HDPE as a sustainable construction material, hence, advancing the research into better performance and successful applications of HDPE concrete.
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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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ItemAggregate Geometry Generation Method Using a Structured Light 3D Scanner, Spherical Harmonics-Based Geometry Reconstruction, and Placing Algorithms for Mesoscale Modeling of Concrete(American Society of Civil Engineers, 2021-08-01)Mesoscale numerical modeling is an effective method of representing concrete as a three-phase material. Accurate aggregate geometry representation is an important aspect in numerical mesoscale modeling of concrete to predict mechanical properties as well as the damage initiation and fracture propagation. In this paper, a novel approach of three-dimensional (3D) scanning of aggregates using a structured light 3D scanner is presented, and parametric geometry reconstruction of aggregate geometries using spherical harmonics is carried out. This novel method of scanning aggregates is a faster, safer, economical, and convenient method of obtaining the 3D geometry compared with other methods. A comprehensive database of aggregate geometries is developed, and an innovative aggregate-placing algorithm for these aggregates is presented to develop the mesostructure. In addition to the proposed geometry generation method, a novel parametric-based geometry generation and distribution method for polyhedral aggregate shapes is presented, including flaky and elongated particles. Finally, aggregate transferring methods to finite-element software and mesh generation methods are discussed with the challenges and possible methods to overcome these issues.
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ItemA review and comparison of design methods for raft substructures on expansive soils(Elsevier, 2021-09-01)Shrink-swell movements of soils cause angular distortion to substructures leading to significant damage to lightweight structures. The built environment of lightweight structures, particularly single-detached dwellings, may compromise the structural performance and cause unforeseen maintenance that may expedite the deterioration of an entire build. Due to the importance of damage minimisation in the design phase of single-detached dwellings, this paper aims to review and compare existing design methods for raft substructures on expansive soils through parametric comparison. The comparison considered parameters related to soil properties, environmental factors and stress conditions, including substructure configuration, affecting the shrink-swell potential of expansive soils. The comparison observed that PTI method calculated beam depths with most proximate values to the overall median, while Lytton and Briaud method calculated beam depths closest to the overall third quartile with respect to all considered design methods. WRI and BRAB method obtained larger values of beam depths, specifically for scenarios with higher plasticity index, liquid limit and longer span, which can be considered as outliers. AS 2870, Walsh and Mitchell method were in the less conservative range based on the range of beam depths calculated. Calculated required beam depths ranged from 300 to 815 mm neglecting outliers with higher dispersion of values when the active depth zone was deeper, the plasticity index and liquid limit were higher, applied uniform load was higher and span of the substructure was longer. This review paper presents the range of probable values, variability and degree of central tendency depending on the values of beam depths calculated by different current design methods that are useful for designers.