Browsing by Author "Setunge, S"

Now showing 1 - 11 of 11

item: Conference-Full-text
Comparison of three HVAC systems in an office building from a life cycle perspective
(2013-11-13) Chen, S; Zhang, K; Setunge, S
This study aims to explore the life cycle environmental impacts of typical heating ventilation and air condition (HVAC) systems including variable air volume (VAV) system, chilled beam system and underfloor air distribution (UAD) system through a case study based on an RMIT office building. Life cycle assessment (LCA) is employed to evaluate the environmental impacts associated with different life cycle phases of HVAC systems. Using carbon emissions as the environmental indicator, ranges of impact for each HVAC system in different life cycle stages are calculated and compared based on the information uncovered in the literature review and relevant LCA inventory database. The system designs on case study are outlined based on the characteristics of a case building. The building was originally equipped with VAV system and was then designed with the chilled beam system and UAD system for comparison purposes. The lists of materials and products used in these three HVAC systems are illustrated, forming the basis of the life cycle assessment. Inventory analyses diagrams have been established based on the activities of HVAC systems in four life cycle stages: manufacturing, construction, operation & maintenance, and demolition. Calculation methods for carbon emissions are established. In particular, inventory data have been developed for manufacturing of HVAC products as well as transportation. We found that the environmental impacts between these three HVAC systems are found to be of different magnitude in different life cycle phase. For instance, the embodied energy of UAD system is the lowest in manufacture stage while that of the chilled beam system is the highest. However, chilled beam system has much more energy saving potential than the other two air conditioning systems in operation stage, and also from a life cycle perspective, the chilled beam system has the lowest environmental impact over a 50 year time frame, and VAV system has the highest environmental impact among the three HVAC systems compared.
item: Conference-Full-text
Concrete bridge deterioration prediction using Markov chain approach
(2013-12-01) Setunge, S; Hasan, MS
Condition monitoring diagnosis of distress and forecasting deterioration, strengthening and rehabilitation of aging bridge structures is a challenge faced by many road authorities in the world. The accurate prediction of the future condition of bridge elements is essential for optimising the maintenance activities. Most authorities conduct regular condition inspection activities followed by a higher level inspection to diagnose specific distress mechanisms. However, network level modelling utilizing condition data to predict the future condition of bridges is a need identified by bridge asset managers. In developing deterioration models for bridges, one of the major drawbacks is the limited availability of detailed inspection data. Condition data collected using discrete condition rating schemes most of the time are inadequate to develop deterministic deterioration models. Among the reliability based models which can be derived using limited condition data, Markov models have been used extensively in modelling the deterioration of infrastructure facilities. These models can predict the conditions of bridge elements as a probabilistic estimate. This paper presents an approach used in the prediction of future condition of reinforced concrete and timber bridge elements using a stochastic Markov chain model. Condition data obtained from two local councils in Victoria, Australia has been used in derivation of the models.
item: Article-Full-text
Deriving Damage Indices for Concrete Girder Bridges subjected to Flood Loading
(2015-12-29) Kalendher, F; Setunge, S; Mohseni, H; Lokuge, W
It is noted that the intensity and frequency of disasters have increased over the past few decades and the damage to infrastructure after a natural hazard has consequently increased. The recent flood events in Queensland, Australia had an adverse effect on the country’s social and economic growth. Due to climate change impacts, it is reported that the frequency and intensity of flood events have increased noticeably in recent years. Failure of transport infrastructure after a flood event significantly affects the community, road authorities and wider stakeholders. Bridge structures are often vulnerable to flood events due to their proximity to water ways and the resultant direct impact of flood on structures. In identifying strengthening needs for vulnerable bridge structures, damage, flood intensity relationship is required. The paper has reviewed different bridge design codes used over several years in Australia for designing the bridges and the method of design for flood loading is identified. Various failure mechanisms of bridges due to flood events have been investigated through analysis of case studies and the most common failure mechanisms of the bridges in Queensland as the result of the 2011 and 2013 flood events have been identified. A case study bridge has been modelled using the general purpose finite element software, ANSYS. The damage to bridges due to impact of floating items under different flood scenarios has been investigated. Damage curves have been generated for the case study bridge under different flood intensities.
item: Article-Full-text
Development of an integrated software tool for whole of life management of concrete storm water pipe assets.
(2015-12-29) Setunge, S; Tran, H
In Australia, there are 500 local councils, each managing 300-1000 km of storm water drainage systems. Majority of the storm water pipes are concrete and are built in 1960’s. Currently the councils use CCTV inspections to assess around 10% of the network and make maintenance decisions for the whole asset stock. This creates a major challenge for asset managers since the decisions are made based on assumed levels of deterioration. Catastrophic failure of pipes due to inefficient management will lead to flooding, which can be a major hazard to the community and infrastructure. The paper presents the outcomes of a study conducted to assess the whole of life performance of concrete storm water pipes. Data from CCTV inspections are converted to a discrete rating and are used to derive Markov chain based deterioration models for the network. Based on these, optimized inspection strategy is developed for the pipe assets combined with a life cycle costing module, tree root invasion model and hydraulic and structural failure modules. The proposed integrated management model is suitable for capturing the whole of life performance of any infrastructure asset
item: Conference-Abstract
An investigation of usability of brown coal fly ash for building materials
(2014-06-23) Gamage, N; Setunge, S; Liyanage, K
The Victoria State of Australia has the second largest reserves of brown coal on earth, representing approximately 20% of the world's reserves, and at current use, could supply Victoria with its energy for over 500 years. Its combustion, annually, yields up to 1.3 million tonnes of fly ash, which is largely use for land-fills. Disposal of fly ash in open dumps cause massive environmental problems such as ground water contamination that may create various health problems. This study focuses on the usability of brown coal fly ash to develop a sustainable building material. A series of laboratory investigations was conducted using brown coal fly ash combined with cement and aggregate to prepare cold pressed samples aiming to test their properties. Initial results indicate that compressive strength satisfies minimum standard compressive strength required for bricks or mortar.
item: Conference-Full-text
Life-cycle assessment for construction processes in building construction: a proposed conceptual framework
(Ceylon Institute of Builders, 2014-06) Sandanayake, M; Zhang, G; Setunge, S; Sandanayake, YG; Fernando, NG; Karunasena, GI
Life Cycle Assessment (LCA) is a powerful tool which can be used to analyse the environmental effects associated with buildings. Even though there are numerous LCA studies carried out on buildings only a handful of studies have concentrated on the construction phase of buildings. The few studies that have considered the construction phase have been reluctant to investigate commercial buildings largely due to lack of data. Most of the studies either ignore or approximate the effects of the construction phase, stating the insignificance of them compared to the total environmental impacts of a building over its life cycle. Many studies have concluded a total effect of 3 to 11percent in the construction phase compared that to the total effects. However, the large impacts at an aggregate level that would concern the designers and the builders have been ignored by these studies. Thus this paper attempts to comprehensively analyse the significance of the construction phase and suggest a methodology for analysing the environmental effects in the construction phase of a building. The outcome of this paper would provide a guideline for the researchers to concentrate on the construction phase in their analyses.
item: Conference-Full-text
Overview of different types of fly ash and their use as a building and construction material
(2013-11-26) Gamage, N; Liyanage, K; Fragomeni, S; Setunge, S
Fly ash is produced, in massive amount, as a waste material of burning fossil fuel (coal combustion) for the thermal generation of electricity. Currently about 900 million tonnes of fly ash produced, worldwide, annually and about 30-40% of this residue is being utilized for various purposes including in cement and concrete production. Disposing the remaining percentage is costly as it should be done carefully to avoid any environmental pollution, mainly groundwater contamination. There are different types of fly ash, including Class F and Class C, generated by burning black coal and brown coal respectively. Class F and Class C are being utilized in making building materials such as concrete, lightweight aggregate, bricks etc. Also fly ash is used as a material for road construction and earth filled dam construction. This paper outlines an overview of using fly ash as a raw material in producing various building materials and methods of how fly ash is being incorporated with other materials. The major benefits and limitations of using fly ash as a building and construction materials are discussed.
item: Conference-Full-text
Pilot study using fibre optics and corrosion sensors for condition monitoring of water pipes
(2013-11-13) Tran, H; Sidiroglou, F; Dissanayake, R; Setunge, S; Qing Li, C
The aging of water infrastructural pipelines and the needs to safely and economically extend the service life are the main drivers for real time monitoring of structural deterioration of water pipelines. Fiber optics sensors provide a means of detecting and monitoring pipeline defects in real time. A common application of fiber optics sensors is to measure the strain and temperature of pipelines by attaching the fiber sensors along the pipelines. Any abnormal change in temperature could be an indication of leak while any excessive change of strain is an indication of tampering or structural damage. This paper presents a pilot study which was aimed to investigate the fibre optics sensors and corrosion sensor as in-situ sensors to provide real time data on corrosion condition of pipelines. Such data would improve the targeting of inspection programs, and allow improved monitoring and decision making for pipe repair or replacement. Furthermore, the data could be used for development of improved deterioration models and thus enhance knowledge of pipe deterioration.
item: Conference-Full-text
A reliability based approach for sustainable management Of public buildings
(2013-11-14) Setunge, S; Zhang, K
Management of aging community buildings is a major cost to many local government organizations in Australia. One of the major challenges is integrating physical or engineering condition ratings with the sustainability issues and community service driven parameters. A new research project continuing at RMIT University in Melbourne is exploring an innovative reliability based approach for deterioration prediction and decision making for sustainable management of community buildings. The paper will present the practices adopted in management of community buildings by six local government agencies in Australia, identifies the community needs and gaps in knowledge. A new integrated methodology for management of community buildings is presented as well as the development of a software tool for implementation of the methodology in local government. The tool covers a building hierarchy, condition monitoring method, deterioration prediction and a decision making process.
item: Conference-Full-text
Shifting qualitative approach in condition monitoring of bridge assets toward a quantitative approach
(2013-11-27) Sagar, A; De Silva, S; Setunge, S
Many existing transportation infrastructure assets such as bridges, overpasses, underpasses, causeways and culverts in developed metropolises are aging and health monitoring data is now becoming a critical aspect when it comes to evidence based maintenance budgeting. Such infrastructure assets are owned and managed through different authorities representing local, regional, state and national levels of governance. Even in the current practice, especially at local and regional level, condition monitoring is predominantly qualitative and as such labour intensive and assessment is subjective. This raises some questions with regard to the decision making processes in budgetary allocations. This paper presents an insight to the current process of qualitative condition monitoring, based on Australian practices, and the quantitative approach covers through a literature review. Advanced methods of real time condition monitoring using remote sensing are also discussed although such modern techniques are currently being limited to large, recently constructed bridges which are relatively young bridges.
item: Conference-Full-text
Theoretical prediction of age dependent crack widths in r/c bridge girders for sustainable asset management
(2013-11-13) Sagar, A; De Silva, S; Setunge, S
This paper discusses the viability of using theoretical crack prediction models as a means of identifying the most appropriate age for maintenance intervention. Usually bridge asset owners rely heavily on superficial observations, especially in early ages, 20-30 years, of a bridge. Visual inspection, a qualitative and subjective approach, is predominantly used as a prime method for bridge condition monitoring by the bridge asset owners. Desired outcomes of qualitative assessment have the limitations of providing satisfactory results and lead to failure in function and safety. Reinforced concrete is a live material which cracks due to shrinkage, creep and flexural stresses. Shrinkage cracks are dominant over the first few years, whereas the flexural and creep cracking, resulting from sustained and periodic loading, can continue whole of life. Depths and widths of these cracks, when reaching a critical level, encourage elements of corrosion at play. The system may enter a vicious-cycle of stiffness and strength degradation, without timely intervention. This paper investigates and proposes a methodology in theoretically predicting most appropriate time of intervention. Authors propose this methodology as a supplement to traditional practice of visual inspection for more informed decision making. It equips bridge owners with greater insight to what cannot be physically perceived by the human eye and could help decision-making to be more objective and cost effective. Research work presented in this paper is, in application, more relevant in reviewing existing bridge maintenance processes adopted by local, regional, state or national levels of governance. Methodology is demonstrated using time-series behaviour of a rectangular R/C section simulating a bridge girder. Post corrosion time series behaviour is not included within the scope of this discussion.