Infrastructure Engineering - Research Publications
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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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ItemSensitivity analysis on energy performance, thermal and visual discomfort of a prefabricated house in six climate zones in Australia(ELSEVIER SCI LTD, 2021-09-15)In prefabricated buildings distinctive construction process and lightweight components affect design strategies and consequences. Therefore, to create more sustainable prefabricated buildings, it is important to understand the effects of their envelope parameters on energy performance and indoor environmental quality. Although previous research have investigated the effects of envelope on energy and indoor comfort outputs, the parameters of lightweight prefabricated envelope are not thoroughly considered. This article quantifies the effects of building envelope parameters on the energy use, thermal comfort and daylighting levels of a prefabricated house built in Australia. A building simulation model was developed and validated by comparing predicted with measured indoor temperatures of the house. The baseline performance for evaluation of energy consumption, thermal discomfort hours and daylight unsatisfied hours were carried out using Transient System Simulation (TRNSYS) tool. Series of regression-based sensitivity analyses (SAs) to identify the most sensitive parameters were conducted by coupling TRNSYS, jEPlus and SimLab. Applications in six climate zones were investigated. The important focus areas found by SA in each climate and their corresponding design responses can be applied across ranges of prefabricated building projects if built in similar climatic conditions. SA results revealed window glazing and shading among the most influential parameters on all targeted performance outputs. The relationship between sensitivity levels to energy consumption and degree days indicated that the type of window has a higher impact on the reduction of energy use in the cooling dominated climates while insulation of wall was found a more effective strategy in heating-dominated climates.
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ItemLean Practices Using Building Information Modeling (BIM) and Digital Twinning for Sustainable Construction(MDPI, 2021-01)There is a need to apply lean approaches in construction projects. Both BIM and IoT are increasingly being used in the construction industry. However, using BIM in conjunction with IoT for sustainability purposes has not received enough attention in construction. In particular, the capability created from the combination of both technologies has not been exploited. There is a growing consensus that the future of construction operation tends to be smart and intelligent, which would be possible by a combination of both information systems and sensors. This investigation aims to find out the recent efforts of utilizing BIM for lean purposes in the last decade by critically reviewing the published literature and identifying dominant clusters of research topics. More specifically, the investigation is further developed by identifying the gaps in the literature to utilize IoT in conjunction with BIM in construction projects to facilitate applying lean techniques in a more efficient way in construction projects. A systematic review method was designed to identify scholarly papers covering both concepts “lean” and “BIM” in construction and possibilities of using IoT. A total of 48 scholarly articles selected from 26 construction journals were carefully reviewed thorough perusal. The key findings were discussed with industry practitioners. The transcriptions were analyzed employing two coding and cluster analysis techniques. The results of the cluster analysis show two main directions, including the recent practice of lean and BIM interactions and issues of lean and BIM adoption. Findings revealed a large synergy between lean and BIM in control interactions and reduction in variations, and surprisingly there are many uncovered areas in this field. The results also show that the capability of IoT is also largely not considered in recent developments. The number of papers covering both lean and BIM is very limited, and there is a large clear gap in understanding synergetic interactions of lean concepts applying in BIM and IoT in specific fields of construction such as sustainable infrastructure projects.
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ItemMulti-objective optimisations of envelope components for a prefabricated house in six climate zones(Elsevier, 2021-01-15)The ever-increasing attention towards implementation of environmentally sustainable buildings necessitates the predictions of energy consumption and indoor environmental quality (IEQ) during early design stages. Prefabrication of buildings changes the construction process and components which affects building performance. Better understanding the effects of envelope components on energy performance and IEQ will inform design decisions leading to the creation of more sustainable buildings. In this article multi-objective optimisations of building envelope were carried out by coupling TRNSYS (Transient System Simulation Tool) and jEPlus + EA (EnergyPlus simulation manager for parametrics + Evolutionary Algorithms). The objective functions to be minimised were thermal discomfort hours (TDH), daylight unsatisfied hours (DUH) and life cycle costs (LCC) while maintaining acceptable sound transmission levels and indoor air quality. The decision variables were envelope components of a prefabricated house. Applications for six different climate zones corresponding to eight locations in Australia were investigated. The optimal solution sets were unique for each climate zone. The optimal solutions achieved 27–31% savings in LCC compared to the baseline. The reductions for TDH varied from 6% to 55% among the locations. As a result of trade-offs, the selected compromised solutions in each climate could achieve better reductions for either TDH, LCC or both.
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ItemAlternative Heating and Cooling Systems for the Retrofit of Medium-Rise Residential Buildings in Greece(WILEY-V C H VERLAG GMBH, 2021-11)The European Union recently set the target of doubling building retrofit rates through the European Green Deal. Currently, more than half of the households’ energy consumption is accounted for space conditioning, with southern European countries experiencing increasing demand for cooling systems over the past decade. Herein, the performance of market‐available heating and cooling systems that can replace the existing low‐efficiency systems in multiresidential buildings in Greece is compared. The study's objectives are to minimize the operating greenhouse gas emissions and the life‐cycle cost. Results demonstrate that air‐to‐air heat pumps have the lowest life‐cycle cost. In areas where natural gas is not available, the replacement of the diesel‐oil boiler with a biomass boiler leads to a 48% to 73% decrease of the operating greenhouse gas emissions. In areas where natural gas is available, the gas absorption heat pump has the lowest operating greenhouse gas emissions, demonstrating a reduction between 40% and 54% when compared to a conventional gas boiler; however, it dramatically increases the life‐cycle cost, making it less attractive than heat pumps and condensing gas boilers. The findings are in line with the current residential space conditioning market, while indicating the potential of biomass boilers and gas absorption heat pumps.