Browsing by Author "Ngo, T"

Now showing 1 - 15 of 15

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Application of nano insulation materials in the sustainable Built environment
(2013-11-19) Gammampila, R; Mendis, P; Ngo, T; Aye, L; Herath, N
Nanotechnology is widely being used in the built environment for its advantages in many improved engineering properties of the nano materials. Nano insulating materials open up new possibilities for ecologically oriented sustainable infrastructure development. The most widely used nano material in built environment is for the purpose of insulation to improve the energy efficiency namely in the buildings and dwellings. Nanotechnology has now provided an effective and affordable means to increase energy efficiency in pre-existing buildings as well as new construction by increasing thermal resistance. The major advantage of nano insulation materials is its benefit of translucent coatings which increase the thermal envelope of a building without reducing the square footage. The intrinsic property of nano insulating material is it can be applied to windows to reduce heat transfer from solar radiation due it its thermal resistant property and the translucent property allows diffusing of day light. The nano insulating material has significant advantage in reducing the operational energy aspects of buildings due to its valuable insulating properties. This paper examines applicable nanotechnology based products that can improve the sustainable development and overall competitiveness of the building industry. The areas of applying nano insulating material in building industry will be mainly focused on the building envelope. The paper also examines the potential advantages of using nanotechnology based insulating material in reducing the life cycle energy, reduction of material usage and enhancing the useable life span. The paper also investigates the operational energy by simulation methodology and compares the reduction of operational energy consumption.
item: Conference-Full-text
Application of nanomaterials in the sustainable built Environment
(2013-11-19) Gammampila, R; Mendis, P; Ngo, T; Aye, L; Jayalath, AS; Rupasinghe, RAM
Nanotechnology is widely regarded as one of the twenty-first century’s key technologies, and its economic importance is sharply on the rise. In the construction industry, nanomaterials has potentials that are already usable today, especially the functional characteristics such as increased tensile strength, self-cleaning capacity, fire resistance, and additives based on nano materials make common materials lighter, more permeable, and more resistant to wear. Nonomaterial are also considered extremely useful for roofs and facades in the built environment. They also expand design possibilities for interior and exterior rooms and spaces. Nano–insulating materials open up new possibilities for ecologically oriented sustainable infrastructure development. It has been demonstrated that nanotechnology has invented products with many unique characteristics which could significantly provide solutions current construction issues and may change the requirement and organization of construction process. This paper examines and documents applicable nanotechnology based products that can improve the sustainable development and overall competitiveness of the construction industry
item: Conference-Full-text
BIM Software Framework for Prefabricated Construction: Case Study Demonstrating BIM Implementation on a Modular House
(2016-01-05) Samarasinghe, T; Mendis, P; Ngo, T; Fernando, WJBS
Building information modeling and prefabrication are concepts that are undergoing intense study in the construction industry. As the technology to implement BIM is commercially available, many industries have started to use BIM in construction related projects. However, BIM implementation can vary significantly according to the nature of the project. Therefore, development of a BIM software framework for a particular industry to meet its requirements is the most efficient way to use Building Information Modeling. This paper will present a BIM software framework developed for prefabricated construction industry and will demonstrate the use of the framework during the design stage of a modular pre-fab house.
item: Conference-Full-text
Experimental investigation on the behavior of RC panels retrofitted with polymer coatings under blast effects
(2013-11-13) Raman, SN; Pham, T; Mendis, P; Ngo, T
Elastomeric polymers (such as polyurea and polyurethane) are finding relevance in retrofitting applications for structures being subjected to blast and impact loadings. This approach, an alternative to various existing retrofitting techniques, capitalises on the elastomeric properties, high strain capacity, high ductility and strength of the polymers, as well as on the ability of the coating layer to act as a shield in containing debris and fragments from the blast. This paper presents the findings from an experimental study undertaken to evaluate the effectiveness of using polyurea coatings to enhance the blast resistance of reinforced concrete (RC) panels. The performed experimental blast trials, designated as Vietnam Trial 2, were conducted in Vietnam with the collaboration from the Vietnam Institute for Building Science and Technology (IBST). Four RC panels with dimensions of 1700 (L) 1000 (W) 60 (T) mm, were tested during the trials. Of these, one panel was an unretrofitted panel while the remaining three were coated with polyurea albeit with a variation in the coating thickness and location. All the panels were subjected to blast loads resulting from the detonation of 1.0 kg Ammonite charge placed at 1.0 m stand-off. The behaviour and responses of various polyurea coated RC panels were compared to the unretrofitted RC panels in terms of panel’s deflections, crack formation and damage to the polyurea coating layers. The findings from the experiments indicated that proposed technique of using polyurea coating to retrofit RC structural elements is practicable and feasible to enhance the capacity of structures against blast loading. A higher level of protection is provided when the protective coating is applied on the blast-facing face of the structure. It was also observed that the bond between concrete and the polymer did not damage even after the the application of the blast loads. These findings assert the possibility of using the proposed technique as a practical alternative to the existing techniques in strengthening structures being subjected to blast effects.
item: Conference-Full-text
Fire Spalling of Concrete Members
(2016-01-05) Hedayati, M; Mendis, PA; Sofi, M; Ngo, T
Thermal instability “spalling” occurs when concrete is exposed to fire. This phenomenon, which happens early after a fire starts (about twenty minutes), is one of the most detrimental effects causing damage to concrete members. It can trigger an immediate degradation of concrete, exposure of steel reinforcements to high temperatures and then eventually can cause failure of the concrete members during or after a fire by decreasing the residual mechanical properties and durability of the structure. In spite of many experimental and numerical studies, the real mechanism of spalling is still not well established. Hence, more comprehensive studies on simulating the behaviour of concrete members exposed to fire to investigate the real physics involved and the affecting factors on this phenomenon are currently lacking. The current study at University of Melbourne is attempted to fill this gap. The lack of understanding of the origin of fire spalling is mainly due to the erratic nature of this phenomenon and inhomogeneity of the concrete structures. To establish a more clear view of the phenomenon further investigation is needed. This paper reports the latest findings on fire spalling behaviour of concrete members and shows the deficiencies of the current experimental work and knowledge.
item: Conference-Extended-Abstract
Ground-coupled cooling in Hanoi
(2013-11-21) Aye, L; Ngo, T; Lhendup, T; Fuller, B
The energy required for space cooling could be reduced by using ground as a heat sink depending on the weather conditions and the ground characteristics. In this paper the theoretical performance of a closed loop ground coupled cooling system for a commercial building in Hanoi has been investigated as an alternative to the conventional air-to-air cooling system. A theoretical computational model for the prediction of the cooling system performance has been developed. It was found that the ground-coupled cooling system performs better (approximately 30% energy saving) than a conventional air-to-air cooling system.
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A holistic model for designing and optimising sustainable prefabricated modular buildings
(2013-11-13) Gunawardena, T; Ngo, T; Mendis, P; Aye, L; Crawford, R; Alfano, J
Prefabricated Modular Structures are increasingly becoming popular as a strategy that can be used to achieve cost effective and speedy construction. However, there is an absence of detailed engineering research or case studies dealing with the structural performance or building optimisation and integration strategies for this technology. This paper presents a conceptual holistic model that can be used to identify the most optimum structural system in a given scenario. A multi-disciplinary approach will be taken to optimise the building by assessing structural systems, materials, sustainability features, constructability and speed and cost of construction. This paper will discuss types of different optimisation strategies adopted in building designs and how they can be modified to assess a prefabricated modular building and what different variables will dominate as key performance indicators in the search for an optimum solution for a prefabricated modular building.
item: Conference-Full-text
Improving the safety of buildings through an innovative sustainable facade system
(2013-11-26) Mohotti, D; Lunmantara, R; Ngo, T; Mendis, P
A building’s façade system is the outer layer of a structure that is designed to provide protection to building occupants and contents from external hazards with varying intensity. In the modern world, many structures undergo different types of dynamic loadings such as blast and ballistics, earthquakes, high winds, hurricanes, tsunamis etc. It is a prime importance of the modern structures to sustain those dynamic loadings without excessive damage. Due to the recent trend towards sustainable development, there are more prevalent uses of innovative systems such as the double skin façade systems, which lead to new challenges in assessing the performance of these façade systems under extreme loadings. This paper presents a review of innovative double layer skin façade system with some finite element modeling to assess the behaviour.
item: Conference-Full-text
Innovative modeling and visualization platform for sustainable cities - Mutopia
(2013-11-13) Mendis, P; Ngo, T; Aye, L; Malano, H; Rajabifard, A
Now more than half the world’s population lives in towns and cities and this proportion will rise to nearly two thirds by 2030. Many cities worldwide are facing acute challenges, and therefore it is essential that all future developments are carried out on a sustainable footing. Through a web-based platform, MUtopia visualises and demonstrates in a quantifiable manner what impact a planned site development would have by representing best practice in all aspects of sustainable urban living on a relatively large scale. Sites may be new suburbs or rebuilt sections of the city large enough to require systematic planning. The project focuses on the development of an integrated modelling, analysis and visualization tool that helps the government and developers to make informed decisions to achieve such sustainable urban development and implementation. MUtopia integrates the streams of energy, waste, water and transport, based on land use, as well as social and environmental factors so that various planning scenarios or dependencies between factors can be tested. It is an integrated BIM and GIS tool. MUtopia would be an international first in an area of growing interest and need.
item: Conference-Full-text
Innovative prefabricated modular structures – an Overview and life cycle energy analysis
(2013-12-06) Gunawardena, T; Ngo, T; Aye, L; Mendis, P
Speed of construction and improved environmental performance are two critical concerns which modern construction industry pays a significant amount of attention on. Employing innovative prefabricated modular structures is one key strategy used to achieve these goals. However, there is an absence of detailed scientific research or case studies dealing with the potential environmental benefits of prefabrication, particularly in the areas of embodied energy savings resulting from waste reduction and improved efficiency of material usage. This paper gives a brief overview of prefabricated modular structures and aims to quantify the embodied energy of modular prefabricated steel and timber multi-residential buildings in order to determine whether this form of construction provides improved environmental performance over conventional concrete construction methods. A case study was carried out on an eight-storey, 3943 m2 multi-residential building. It was found that a steel-structured prefabricated system resulted in a significantly reduced material consumption of up to 78% by mass compared to conventional concrete construction. However, the prefabricated steel building resulted in an increase (~50%) in embodied energy compared to the concrete building. This form of construction has the potential to contribute significantly towards improved environmental sustainability in the construction industry.
item: Conference-Full-text
Nanoengineering concrete for sustainable built environment: a review
(2013-11-23) Rupasinghe, M; Mendis, P; Gammampila, R; Ngo, T
The construction industry is a major consumer of material and energy sources in the world. Among all the materials used in construction, concrete, which is the most widely used, can have a significant impact. Meanwhile, nanotechnology is one of the most influential technologies in this century and it has significantly impacted the construction sector. Better understanding and engineering cementitious materials at nanometer scale can result in novel construction materials which are more strong and durable than conventional materials. Engineering concrete at the nano meter scale includes the incorporation of nano sized particles into concrete at suitable proportions and methods. Nano Silica is one such nano material which has shown to enhance the overall performance of concrete. Incorporation of nano Silica at smaller volume fractions has shown to result in higher compressive and flexural strengths at early ages, improved hydration characteristics and reduced porosity and water absorption when compared with conventional cementitious materials. The impacts of other nano materials such as CNTs, nano TiO2, nano Al2O3 and nano TiO2 on concrete are also promising. While nano materials acts as fillers and provide nucleation sites for cement hydration, nano SiO2 also acts as a pozzolanic material, increasing the amount of stiff CSH within the hydrated cement paste, resulting an improved microstructure. Nanomaterials can also pave the path to reduce the cement content in concrete than in conventional mixes while maintaining same strength characteristics, which will lead into the production of a „greener‟ concrete. Numerical models of the composite material validated with experimental results can be used to come up with optimum nano material contents and performance. This paper reviews the efforts, current status and effects of nano modification of cementitious materials and numerically modelling strength properties. These innovative materials will be of high performance and less energy consuming, which will lead towards sustainable construction practices.
item: Conference-Full-text
Numerical simulation of impact and penetration of ogvial shaped projectiles through steel plate structures
(2013-12-06) Mohotti, D; Ngo, T; Mendis, P
There is an urgent need to develop light-weight protective structures with a sufficient protection to prevent the damage occurring during extreme loading events such as blast and ballistic impacts. This study is a part of ongoing research to develop light weight amour materials which can sustain under those severe conditions. Numerical modelling with explicit finite element code LS-DYNA has performed with realistic geometries. Ballistic protection class BR7 in European norm EN 1063 considered, thus penetration of different shaped projectiles through thick steel plates was examined. Since the geometries and materials of the projectiles have a very significant influence on the outcome of this research detail modelling of the projectiles was performed. For the purpose of this paper, perforation mechanism of 7.62mm APM2 bullet through 6mm thick Weldox 460E high strength structural steel plate was examined. Largrangian methods combined with Johnson-Cook material model available in the LS-DYNA were used for the numerical simulations. Finally the ballistic limit curve for the 6mm thick Weldox 460E plate perforated by APM2 bullet was obtained. Results were compared with the analytical models.
item: Conference-Full-text
Performance-enhancement of phase change materials for energy conservation in the built environment : a state-of-the-art review
(2013-12-06) Nguyen, QT; Ngo, T; Mendis, P
Energy conservation has become a critical issue in the world today as strong economic growth is unfeasible without a sustainable strategy of energy conservation. Apart from long-term environmental impact, a well-managed strategy for energy consumption even results in improvement of the financial performance in the short term. Phase change materials (PCMs) with its capacity of storing thermal energy as latent heat is a viable approach of the utilization of solar heat, a green source of energy, and the optimization of energy consumption in buildings. However, the obstacle that prevents PCMs from being applied widely in practice comes from its poor performance in terms of heat transfer and shape stabilization. This article, therefore, presents a critical review of PCM and effective methods to boost its performance in terms of shape stabilization and transient heat transfer.
item: Conference-Full-text
Seismic performance of super tall buildings
(2013-11-18) Herath, N; Mendis, P; Ngo, T; Haritos, N
With the rapid population growth and dynamic economic developments, the demand for residential, mixed use and commercial buildings has been increasing significantly all around the world. Due to the excessive increase in height of buildings in this era, there is a significant impact on the methods used to analyze and design of tall buildings. There is a clear acceptance within the engineering community that the specifications given in codes of practice are not suitable for very tall buildings. General concepts, current methods of analysis and seismic performance of super tall buildings are reviewed in this paper. Further the effect of higher modes on the performance of super tall buildings is also discussed.
item: Conference-Full-text
Thermal performance of concrete with PCMS
(2013-11-13) Jayalath, A; Mendis, P; Aye, L; Ngo, T
Development of energy efficient and environmentally friendly materials to reduce energy consumption in buildings is a major concern in today’s building and construction industry. Sustainable development of energy efficient materials in buildings needs to consider not only the mechanical properties such as strength and stiffness of structural materials but also thermal properties which includes heat capacity and thermal insulation. Concrete as most widely used construction material has a great potential to improve its heat storing capacity or thermal mass for their effective usage in buildings. One of the promising solutions is thermal energy storage with Phase change materials (PCM). Concrete incorporating PCM improves the thermal mass of the building which reduces the space conditioning energy consumption and extreme temperature fluctuations within the building. The heat capacity and high density of concrete coupled with latent heat storage of PCM provides a novel energy saving concepts for sustainable built environment. Microencapsulation is a latest and advanced technology for incorporation of PCM in to concrete which creates finely dispersed PCMs with high surface area for greater amount of heat transfer. Moreover PCM absorbs the excess energy during cement hydration and reduces the possibility of formation of cracks within the concrete. This paper reviews available literature on Phase change materials in concrete, its application and discusses finite element modelling of thermal performance of composite concrete.