Infrastructure Engineering - Theses
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ItemStatistical-dynamical modelling of catchment water balance: climatic and vegetation controls on hydrological fluxes( 2005)The prediction or modelling of catchment water balance is a fundamental hydrological question. So many natural resource management problems rely on accurate modelling of catchment water yield. Both Australian and global water resources are likely to face new and increased pressures in the future as a result of land-use changes, climate change and increased demand for water from both urban and agricultural users. However, the variability of catchment water balance, as well as the sources and timescales of this variability, still remains insufficiently understood. The principal aim of this thesis is an analysis of the water balance of Australian catchments. Using a variety of models, particularly recently developed probabilistic soil-moisture accounting models, catchment water balance and soil moisture variability are examined at different timescales, with particular emphasis on the mean annual timescale of catchment water balance. Recently published stochastic soil-moisture accounting models are presented in detail. This survey highlights the assumptions of the models, the theoretical and observational background to these assumptions, as well as the solutions, limitations and possibilities for improvement of the models. These models are then compared with observational data, and further extensions and solutions to some of the models are presented and discussed. Water balance variability at other timescales is also considered, by testing and extending theoretical hydrological models, resulting in a clearer understanding of the relative roles of climate, soil and vegetation to the variability of catchment water balance.
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ItemThe effect of adverse possession on part of a registered title land parcel( 2003-01)This thesis began as an investigation of the effect of adverse possession upon the land market where the adverse possession extends only to a small portion of the abutting parcel and the subject land is under a title registration scheme. The consequence of such adverse possession on part only of a parcel is that the location of the boundary demarcating the limits of the respective domains of two adjoining land parcels may be displaced. If part parcel adverse possession effectively transfers ownership of a small portion of an abutting parcel, the boundaries are shifted consequent to long term occupation, and will prevail over the strict technical legal boundary. In a registered title land system the occupational boundary then prevails over the legal boundary as certified in the register notwithstanding that registered title schemes purport to confer conclusiveness upon register entries. Alternatively, the registered proprietor’s estate is not paramount where any part of the proprietor's parcel has been adversely occupied. Consequently the occupier has an interest in the proprietor's land that is not disclosed in the register. Inspection of the register and reliance upon the inspection is insufficient to ascertain the complete legal status of the particular land holding. Inspection with consequent reliance upon the register is the major function of a registered title scheme. Alternatively, if part parcel adverse possession is ineffective to transfer ownership of registered land, the technical legal boundary prevails over the occupational boundary despite the fact that it is not the boundary accepted by the parties involved as governing. Both alternatives present a problem to the orderly conduct of the land market. Where occupations prevail, the prudent market participant takes precautions besides relying on inspection of the register. Where the legal boundary prevails, the participant seeks confirmation that the occupational and legal boundaries coincide. Another alternative utilised in some registered title jurisdictions empowers a court to transfer small sections to an adjoining landholder where a building or similar improvement is erected so that it encroaches upon the adjacent holding. This alternative was included within the ambit of the thesis as it developed. The aim of this research was the formulation of the best solution suitable for a registered land system with particular reference towards a uniform solution suitable for adoption in all Australian jurisdictions. The existing systems utilising adverse possession and statutory encroachment were evaluated against three recent law cases that illustrate the workings of these systems including perceived shortcomings. These lawsuits serve as a test against which the existing systems are compared and evaluated and were also used to evaluate the proposed solution. The results suggest that adverse possession alone should not override the purpose of the register which is to fully disclose the proprietary interests in land parcels. It was concluded that a necessary step in acquiring title to land through adverse possession involves the registration of the interest acquired. Whereas the present modes of dealing with the boundary problem are adequate, it is concluded that the best mode is that of statutory encroachment because it best serves several competing interests. Adopting the proposed solution would involve change and compromise in some of the Australian jurisdictions; these being necessary to adopt a uniform scheme throughout Australia. The proposed solution has added benefits of removing an illogicality from some of the present systems, eliminating encouragement for an off-register land market, and fosters an accurate public land register.
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ItemA multi-component indicator of stream condition for waterway managers: balancing scientific rigour with the need for utility( 2000-01)Measuring the environmental condition of waterways is of interest to river managers, governments and the community. In the State of Victoria, Australia and elsewhere, there is concern that environmental values of streams are declining and that information about the environment, needs to be considered when river management decisions are being made. This thesis explores the use of environmental indicators as a tool to assist management of rivers. The promise of indicators is that they can turn large amounts of environmental data into simple, timely results and thereby provide an effective means of incorporating this information into river management decisions. It is also suggested that indicators will be useful for measuring the outcomes of management intervention and provide feedback on the effectiveness of strategies. Can environmental indicators live up to this promise? This thesis examines this question by reviewing indicator systems that have been developed by others and then exploring, in detail, the Index of Stream Conditions (ISC) that is is intended as a tool to assist the management of rivers in Victoria. I argue that environmental indicators have a role at the level of regional waterway management authorities but only if they are closely aligned with managers’ needs. Without consideration of non-technical issues, indicators are unlikely to be used, so it is important to establish a balance between pragmatic constraints and the need for scientific rigour. A procedure to achieve this balance is described in this thesis and was applied to the development of the ISC. Selection of indicators and the choice of indicator frameworks are explored and the value judgements behind the interpretation of indicator scores are examined. It is also important to consider the accuracy and sensitivity of indicators. Possible objectives for the use of indicators include benchmarking, detecting change and providing information to trigger management intervention. Case studies are used to explore the performance of indicators in practical applications in streams in Victoria in relation to these objectives. Extensive use is made of non-traditional statistical procedures, including bootstrapping, and results are presented that show the likely variance of indicator scores and the relationship between indicator objectives and required sampling effort.
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ItemEnhanced value for money outcomes through alliance techniques: a framework for public private partnerships in Australia( 2007)While much of Australia's current infrastructure has been traditionally provided by the public sector, there is a recent trend towards private organisations providing infrastructure services. Governments have realised that to maintain economic competitiveness along with social cohesion, the value of private finance within infrastructure development can not be understated, whereby the private sector invests in infrastructure and provides related services to the public sector at a reasonable cost. Whilst there are a multitude of variations, this concept is commonly known as a Public Private Partnership (PPP). Recent Public Private Partnership projects in the developed world have focussed heavily on achieving Value for Money (VfM) outcomes for governments through the application of robust polices and guidelines. This study has investigated current Australian PPP policies (both State and Federal) to determine whether enhanced Value for Money outcomes can be achieved through the integration of Alliance techniques. Value for Money in a theoretical sense is defined as the functional performance achieved for a given consumption of resources. The actual quantum of Value for Money calculated is not important; the focus being on the relativity between the traditional PPP model and a model that utilises Alliance techniques. Specific techniques and perceptions of Alliance Contracting were investigated through a series of surveys with direct users from both the public and private sectors, and the level of applicability to a PPP process was established. A detailed review of Australian and UK PPP projects was undertaken and a series of in depth case studies were investigated to better understand the practical implications and the current shortcomings in current PPP policy approaches. The framework for a new approach was developed and further tested and refined through an industry workshop with key PPP representatives from a variety of sectors. The study concludes with drafting new guidelines for PPP projects, to enhance Value for Money outcomes for all parties. Whilst it was found that not all Alliance techniques would enhance Value for Money outcomes, a number of key areas were identified where improvements could be made to current practices, namely: • Development of policies to mandate interaction between the State, bidders and end users at critical stages of PPP projects. Proposed enhancements to the current PPP policy model have been developed, including: • Incorporation of relationship based Alliancing techniques to assist with the complex and varied contractual nature of a PPP project; • A credit based abatement regime which incentivises parties to outperform specific outputs in the form of credits which can then be used against underperforming areas; and • The appointment of an Independent Reviewer to oversee the long term management of the contract.
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ItemAn evaluation framework for privately funded infrastructure projects in Australia( 2001)For reasons of efficiency, accountability for performance, productivity and monetary policy, Australian governments will continue in the short to medium term to involve private firms in the provision of social and economic infrastructure. This study investigates the provision and management of engineering infrastructure such as roads, water supply, airports and electricity in the context of private involvement. Private involvement is possible through contracting out specific tasks or projects, private responsibility for the provision and operation of infrastructure services, (the many options here collectively being called concession agreements with subsequent contractual arrangements), or full privatisation of service provision. This study focuses on the initiation of projects involving the provision of infrastructure by privately funded concession contracts and considers the decisions taken by Government during this phase of a projects life. The study has investigated appropriate methods to evaluate and assess the likely outcomes from such projects from the perspectives of Government, Private Proponent and other stakeholders who include the general public, users of the service, lobby groups etc. (The 'other stakeholders' have many different objectives and are collectively referred to throughout this study as public(s) to reflect the situation that there is no single collective public view). A detailed review of the potential and likely demand for private involvement in infrastructure in Australia concluded that the use of concession contracts as a delivery system will continue and is likely to become more popular. This conclusion has been confirmed by recent statistics from the Australian Bureau of Statistics. A review of project initiation practice has included both theoretical techniques and actual procedures and actions adopted for recent Australian projects. This review has considered all phases of a project's life, from Government initially approaching the private sector until the service life of the concession contract is complete, typically a 20 to 30 year period. An extensive number of Australian case studies have been reviewed to ascertain trends and relationships between the project initiation process and the success or otherwise of project outcomes. Findings of this review were that concession contracts are very complex, having a multitude of facets and that generalisations in terms of modelling and or decision processes are inadequate to truly accommodate all likely scenarios. A number of areas were identified where improvements can be made to current practices, namely: - Greater separation of government's, dual roles to provide functions of governance and to provide economic management - Changes to current project implementation practice through the inclusion of confirmation of project objectives, through a detailed technical review of the project prior to award and in fine tuning of when certain information is provided - The inclusion of risk modelling into the project initiation and approval process to improve the quality of decisions. Proposed enhancements to these areas have been developed and in part verified through: - The proposal of the concept of separating the dual roles of government through the use of an "Independent Regulator". - The development of detailed decision making guidelines, based on risk analysis, to assist in the choice of the most appropriate proponent to award a concession contract given a number of invited submissions. The proposed criteria for award of a concession contract includes consideration of technical, financial, social and environmental issues.
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ItemTwo-dimensional simulation model for overland flow in contour basin irrigation layouts in Southeast Australia( 2001)Contour basin irrigation layouts are used in Southeast Australia to irrigate rice, winter cereals and pasture. These layouts are developed predominantly on heavy cracking soils with low infiltration rates. Contour basins are made by constructing banks across the slope, which are built by borrowing soil from the adjacent area inside the basin and leaving a toe-furrow along the side banks. Irrigation in these layouts is carried out by sequentially watering a set of basins. This involves filling one basin to the desired depth and retaining the water until it infiltrates into the soil while at the same time allowing the excess water to drain into the next downstream basin as well as back into the supply channel. In this work a physically based two-dimensional simulation model that incorporates all the features of contour basin irrigation systems as used in Southeast Australia was developed. The model's governing equations are based on a zero-inertia approximation to the two-dimensional long wave equations of motion. The equations of motion are transformed into a single non-linear advection-diffusion equation in which the friction force is described by Manning's formula. The empirical Kostiakov equation and the quasi-analytical Parlange equation are used to model the infiltration process. The governing equations are solved numerically by using a split-operator approach. For a regular grid discretization, the method of characteristics coupled with bicubic spline interpolations is used. A two-dimensional Taylor series expansion, in conjunction with the method of characteristics, was used for irregular grid discretization. Field studies were conducted during the 1998-99 and 1999-2000 irrigation seasons on commercial lasered layouts to evaluate their irrigation performance. The trials were conducted in the vicinity of Deniliquin, N.S.W. Two irrigation events in each irrigation season were monitored. The first trial was conducted during the first irrigation of the season on a dry heavily cracked soil while the second event was carried out 10-20 days after the first irrigation. This latter irrigation represented a typical within-season irrigation. The studies involved the collection of all the soil and hydraulic parameters and followed typical water management practices used by a farmer. The trials yielded a full set of field data including surface elevations, inflow and outflow, waterfront advance, overland flow depth and pre- and post-irrigation soil moisture status. A full water balance was carried out to assess irrigation performance. The water balance of the experimental bay indicated that the deep percolation loss ranged from 22% to 37% of the total water applied. The main reason for high percolation loss is ascribed to poor drainage from the bay. This is attributed to several factors including local microtopography, poorly maintained toe-furrows and excess water application. The developed model was validated using the experimental data collected during the field studies and infiltration parameters collected from the literature. Different contour basin layouts are used for the model validation to demonstrate the model's capability for incorporating all the key layout features. The applicability of the model was demonstrated with line and point inflow, toe-furrows within the basin, drainage outflow into the supply channel and into a downstream basin. These characteristics are included in models of regular and irregular basins. Overall, the model performs well against the field data and in defining all the characteristic features of contour layouts. The model was also used to study the effect of key design and management parameters on irrigation performance. This was conducted simulating hypothetical cases of contour basins to study the effect of (i) aspect ratio (ii) longitudinal slope (iii) inflow rates (iv) local microtopography, in single basins and the effect of (i) contour interval and (ii) number of outlets in multiple basins. Finally, general design and management guidelines for contour basin layouts are suggested. In this regard it must be noted that these guidelines are only intended to assist irrigation designers and practitioners in conceptualising the effect of the main design factors on layout performance. It is implied that the model will be used to analyse alternative design options in each individual case.
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ItemGetting a fair deal: efficient risk allocation in the private provision of infrastructure( 2000)Over the last decade there has been an increasing trend by governments in Australia and throughout the world to use the skills and expertise of the private sector in developing and implementing infrastructure projects. The agreement for these projects must allocate responsibility for dealing with the risks which may arise to either the government directly, or on behalf of consumers, or to the private sponsor. This thesis investigates risk allocation in the private provision of infrastructure, particularly in build-own-operate (BOO) and build-own-operate-transfer (BOOT) projects. Its primary objective is to identify a framework for efficient risk allocation so that decision makers can assess the efficiency of the risk allocation in past projects and can attempt to increase the efficiency of the risk allocation in future projects. This thesis defines an efficient situation as one where the risk allocation cannot be varied without the total risk premium for the entire project being increased, and approach based on Pareto optimality. As it is almost impossible to determine the true risk premium charged by parties for risk bearing, risks should be allocated to the party best able to control and manage them. This is explained to mean the party which is best able to control or manage the likelihood of the risk occurring or the size of its consequences if it does occur. It also means the party with the best access to reasonable mitigation techniques and the party which is least risk averse. Those exogenous risks which are not easily allocated in this way should be shared so that both parties, the sponsor and the government, have an incentive to manage them. Some of the options for sharing these risks are examined. The application of the theory of efficient risk allocation is simplified by using a categorical risk framework. This approach is then tested on seven case studies of recent Australian projects spanning several industry sectors. Finally, the theoretical hypotheses and assumptions are tested in a survey of key participants in the Australian private infrastructure industry. This survey not only confirms that the basic theory for efficient risk allocation is valid but also identifies the key areas of concern to the private sector when it considers project risk allocation. Risks of concern are identified and possible options for risk sharing are investigated. This thesis concludes that it is possible to achieve efficient risk allocations in practice, and that by achieving this outcome transaction costs can be reduced, allowing cheaper infrastructure services to be supplied to the community. However, several hurdles to achieving this outcome are identified. These include the peculiar characteristics of banks and their position in projects funded using non-recourse project finance, and the fact that most private firms fail to value potential upside risks as highly as they fear potential losses due to downside risks. More work is needed to understand and overcome these hurdles if efficient risk allocation is to be achieved in the real world. It is only then that governments can be sure that they are providing private sector infrastructure services to the community at the lowest overall cost.
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ItemSeismic performance of concrete beam-slab-column systems constructed with a re-usable sheet metal formwork system( 2007)This report describes an investigation of seismic performance of a ribbed slab system constructed with an innovative re-usable sheet metal formwork system. Experimental results from quasi-static cyclic lateral load tests on half-scale reinforced concrete interior beam-slab-column subassemblages are presented. The test specimen was detailed according to the Australian code (AS 3600) without any special provision for seismicity. This specimen was tested up to a drift ratio of 4.0 %. Some reinforcement detailing problems were identified from the first test. The damaged specimen was then rectified using Carbon Fibre Reinforced Polymer (CFRPs), considering detailing deficiencies identified in the first test. The repaired test specimen was tested under a lateral cyclic load as per the original test arrangement up to a drift level of 4%. The performance of the repaired specimen showed significant improvement with respect to the level of damage and strength degradation. The results of the rectified specimen indicate that the use of CFRPs may offer a viable retrofit/repair strategy in the case of damaged structures, where this damage may be significant. Two finite element analysis models were created and results of the first test were used to calibrate the FE model. The second FE model was used to obtain detail information about stress and strain behaviour of various components of the beam-column subassemblage and to check the overall performance before carrying out expensive lab tests. It was concluded that finite element modelling predictions were reliable and could be used to obtain more information compared to conventional type laboratory tests. Time-history analyses show that the revised detailing is suitable to withstand very large earthquakes without significant structural damage.