Infrastructure Engineering - Theses
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ItemObject-oriented concepts for land and geographic information systems( 1991)This research studies the impact of Object Oriented Programming Systems (OOPS) and their underlying concepts on Land and Geographic Information Systems (LIS/GIS) in Australasia. This research considers GIS software development and conceptual data modelling aspects, and the strong relationship with proposed spatial data transfer standards. Conventional programming techniques appear to have reached their limit in coping with complex and diversified applications. "Something better' is envisaged for future software developments and data models in LIS/GIS. The relatively new object-oriented design method is reviewed and a much improved object-oriented software module for the daily maintenance operations in a Digital Cadastral Data Base (DCDB) is presented as an example. This development allows a significant improvement of the spatial accuracy of DCDB systems and its graphical user interface (GUI) represents a much better data quality visualisation tool. The choice of the right conceptual data model for GIS has a strong impact on proposed spatial data transfer standards and the way in which future Australian GIS communities will 'view' or model their real world. It has therefore been important to critically review these proposals in the Australian context.
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ItemManufacture and properties of prepacked aggregate concrete( 1984)The properties of prepacked concrete have long been studied and compared with those of normal concrete, although very little is known about its strength and deformation behaviour. Either by experiment or theory these aspects have been described in different ways. This thesis describes some experimental programmes on prepacked concrete that include its manufacture and a study of its strength, deformation and failure mechanism. To compare these aspects, normal concretes having the same water-cement and aggregate-cement ratios were made and tested under the same condition. The experimental work investigates the use of different types of admixture in grout in order to improve the strength of prepacked concrete. Among them the expanding admixture was found to be most suitable. Data are presented on some properties of grout using different types of admixture at various sand-cement ratios. Along with the strength investigation, investigation on modulus of elasticity, creep and shrinkage were also carried out. Tests of creep and shrinkage reveal that the magnitudes of both in prepacked concrete were much lower than in normal concrete. Different aspects of the failure mechanism of prepacked concrete are also presented and discussed.
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ItemModelling the seasonal variation of groundwater recharge and yield of the Barwon Downs aquifer, south-western Victoria( 1996)The Barwon Downs Aquifer in south western Victoria has long been recognized to have extensive groundwater resources. It is also an important source of supply in Barwon Water's drought emergency management plan. An understanding of the aquifer behaviour in relation to its recharge and withdrawal rates is essential for sustainable development. The main aim of this modelling exercise is to evaluate the present groundwater use and estimate the maximum possible extraction from the aquifer without serious consequences, and hence evaluate the groundwater management options and possible augmentation of the Barwon Downs Wellfield. A 2-layer finite difference model is used in groundwater modelling, and a simple hydrologic model is used to estimate the groundwater recharge. The hydrologic and groundwater models were calibrated against potentiometric heads at 38 locations. Although further effort could improve the calibration results, the model calibration is deemed sufficient for the purpose of this study. In general the potentiometric heads simulated by this groundwater model are within 2 m of the recorded heads. The calibrated model has been used to investigate groundwater extraction under various options. The model suggests that continued withdrawal of 8,000 ML/year for 10 years may not be sustainable. However, continued withdrawal of 12,600 ML/year for a period of one or two years during drought is sustainable. The model further shows that a maximum emergency extraction of up to 40,000 ML/year over a one-year period may be sustainable provided that the wells are left to recover for a period of at least 10 years. The groundwater resources thus appear to be best limited to conjunctive use with surface water during droughts. The hydrologic model also estimates that the recharge rate to the aquifer is about 9% of the total rainfall, and that to the overlying layer is about 3% of the total rainfall.
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ItemLarge scale, long term, physically based modelling of the effects of land cover change on forest water yield( 1999)The question was asked: is it possible to realistically and spatially simulate the water balance of forests at large scales for long periods in a way which responds to land cover change. The answer to this question was pursued by attempting to construct a new model and applying it to a 163 km2 catchment area near Melbourne, Australia.
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ItemPerformance of steel framed domestic structures subjected to earthquake loads( 1997)This thesis investigates the performance of cold formed steel framed domestic structures subjected to earthquake loads. These structures generally include one and two storey houses, comprising steel wall framing, exterior veneer cladding and internal lining. The dynamic, non-linear performance of such structures during earthquakes is simplified to static linear behaviour for design purposes using the structural response modification factor, Rµ. This factor is defined as the product of the structural ductility reduction factor, Rµ, and the over-strength of the system, Ω. This thesis develops a rigorous technique for the determination of Rµ and the application of this technique is demonstrated for a proprietary framing system. This is achieved using novel non-linear, transient dynamic finite element models of these structures subjected to earthquake loads. The model parameters are estimated from unique experiments conducted on representative structures using a shaking table. It is shown that the framing system considered is non-ductile (ie Rµ≈1). This result directly contradicts the assumed ductile behaviour of these framing systems as specified in the Australian earthquake loading standard, AS 1170.4. The significance of this is that current design practices are unconservative and therefore underestimate the earthquake loads on these structures.
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ItemLow flow hydrology: application of a systems approach( 1990-06)Australia is not only the driest continent, but its streams are among the most variable in the world. To date in Australia there has been no large-scale study of Australia’s low flow hydrologic characteristics, and consequently there is a fundamental need to develop methods that can be readily used to assess the hydrology during times of low flow. This thesis describes the development and derivation of a methodology for the estimation of low flow characteristics and yield in small ungauged rural catchments. The methodology has been applied to 184 catchments located in New South Wales and Victoria, in south-eastern Australia. A systems approach was adopted in which multivariate techniques were used to develop relationships between low flow parameters and climatic and land information data. The low flow and yield parameters considered include: descriptive statistics of monthly and annual flows, ratio of baseflow to total streamflow volumes, streamflow recession constants, flow duration curves for daily, monthly and annual durations, low flow frequency curves for durations from 1 to 284 days, duration of low flow spells below a given threshold, deficiency volume of low flow spells below a given threshold, estimate of storage to satisfy a specified draft at a given level of reliability, and parameters of a simple rainfall-runoff model for conversion of daily rainfall to monthly streamflow volumes.
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ItemPerformance of brick-veneer steel-framed domestic structures under earthquake loading( 1997-11)This project investigates the performance of brick-veneer cold-formed steel-framed domestic structures when subjected to earthquake-induced loads. It focuses on the effects of the so-called non-structural components, namely, plasterboard lining and brick veneer cladding. An extensive testing program was conducted on a full scale one-room-house measuring 2.3m x 2.4m x 2.4m high. This house was tested at various stages of construction to assess the contribution of the various components. Different types of loading, including non-destructive swept sine wave, destructive pseudo-static cyclic racking and simulated earthquakes were employed to obtain the various characteristics of the structure. The testing program on the test house was complemented by further tests on critical components such as brick ties and plasterboard connections. Detailed analytical models were developed and verified against the experimental results. These models were then used to conduct a sensitivity analysis to study other configurations, identify critical parameters and develop design guidelines. The experimental and analytical results have shown that the plasterboard wall lining can provide lateral bracing to domestic wall frames since they effectively act as shear walls. The performance of wall lining is greatly enhanced when set corner joints, ceiling cornices and skirting boards are considered. The capacity is increased by more than three times when these extra components are taken into account. Plasterboard also exhibits high damping and energy absorption capacity which are beneficial under earthquake loading. Furthermore, the strength and stiffness contributions of plasterboard lining and strap cross braces are additive.
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ItemDrawdown and river bank stability( 1999-05)Drawdown is the lowering of the water level, and can refer to the groundwater, or the level of a river. In this thesis it will generally refer to a river going from a high flow condition to a lower flow condition. The rate of drawdown is expressed as either the change in flow per unit time, or the change in stage per unit time. The later is of most importance in terms of bank stability. It is commonly thought that 'rapid' drawdown of river levels adversely affects river bank stability. This concern over river banks stems largely from work done following the failures of some earth dams once the storage had been drawn down. Little further work has been done in looking at whether the same approach can be used for assessing the likely impact of drawdown on river banks. Given this apparent lack of information and knowledge on drawdown failures, this work investigated the effect of drawdown rates on river bank stability, and in so doing a better understanding of the key parameters is gained. The task was approached from three angles. The first was an analysis of the historical records to see what the rates of fall prior to regulation were, and whether they had changed since regulation. The results indicated that it can not be shown conclusively that the rate of draw down has increased since regulation. They also show that there has been a marked change in the frequency at which drawdown events of a given size occur, particularly the high incidence of lower drawdown rates. The second approach to the investigation was the field work component. The focus of the field work was the response of the near bank watertable to changes in river level. Other data collected were soil particle size distribution, bank profile monitoring (through the use of photogrammetry) and permeability testing. The results of this work show that the near bank watertable was easily able to match the rate of drawdown seen in the river channel. The particle size analysis and permeability data confirm this observation. The third prong was the smallest and consisted of some very simple modelling which further showed that drawdown rate is not so critical for river banks. The findings of this thesis are that draw down at the current rates is not a factor in the failures observed on northern Victorian rivers. The rate of drawdown has not significantly changed since regulation, although the frequency at which specific rates of drawdown occur, has changed. Observational data shows that elevated and sustained nearbank watertable levels cause seepage failures that look like drawdown failures. Permeability is the key factor in the response of the near bank watertable and should be used as a guide to the maximum drawdown rate.
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ItemEvaporation from an agricultural catchment: a field and theoretical study of evaporation( 1983-05)This is a field and theoretical study of the evaporation component of the hydrology of an agricultural catchment. The aim of the study was to improve the evaporation section of the Australian Representative Basis Model, ARBM. ARBM is a physically based computer model of catchment hydrology. It was developed for use in conjunction with the representative Basins Project. The catchment selected for this study was the Warrambine Creek Representative Basin, No. 2.15. A major part of the study was the development of equipment to directly measure evaporation in the field. Two sets of equipment were developed. One system was based on the energy balance method of evaporation measurement. The other system was based on the eddy correlation method. In its final form, the energy balance equipment proved most satisfactory. At the study site over 100 days of complete data was collected. However this data was discontinuous due to instrument and data recording faults. The data collected was used in the testing of various components of the evaporation model. A detailed analysis was undertaken to estimate the likely errors in the computer values of evaporation. This analysis showed that little error could be expected when evaporation was measured over a wet surface. For a dry surface, the analysis predicted that erratic results could occur. This prediction was confirmed with experimental evidence. The development of the eddy correlation system was less successful. This occurred because of the late start to this section of the work and because of the innovative nature of the equipment which was developed. A microprocessor system was designed to replace the eddy correlation analogue computers. This system offers many advantages over conventional equipment. Unfortunately it was only developed to the laboratory testing stage. Also an infrared hygrometer was designed. This too was only tested in the laboratory. Although no field measurements of evaporation were made with this equipment, additional theory and insight into this method was obtained. The performance of any hydrological model depends on the reliability and representativeness of its input data. This data is supplied by a Bureau of Meteorology climate station situated only 3 km from the study site. The location of the climate station appears to be non-representative of the catchment in general. Thus climatic data from the two sites was compared. Little difference was noted in dry bulb temperature and rainfall data. Wet bulb depressions were slightly different. A poor correlation of pan evaporation was found. It was also found that the global radiation data collected at the climate station was worthless due to an instrument fault. The evaporation model of ARBM was examined in detail. In particular, the parameter known as potential evaporation, PE, was examined from first principles. It was found that PE is poorly defined. PE was re-defined and prediction formulae were derived. These formulae were used in a new PE model for ARBM. The model which predicts the diurnal variation of evaporation was examined and found to be satisfactory. Particular improvements to the equipment and topics of further study were recommended.
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ItemThe dynamics of diffusion of corporate GIS( 1998-09)The hypothesis of this research is ‘Diffusion of GIS in an organisation is affected by the qualities of GIS as seen in the context of the structure of the organisation’. A review of the GIS diffusion literature establishes the theoretical background of the research. It is argued that the qualities of a corporate GIS reflect the GIS qualities mentioned in the hypothesis. These qualities are identified and applied to Rogers’ model of organisational innovation process to give a model of diffusion of a corporate GIS, which serves as a working model for the hypothesis. The model describes how the qualities of a corporate GIS can affect GIS diffusion, and predict four sets of relationships as follows . - A corporate GIS is made up of modules of GIS which play the role of either a business process or an infrastructure, with an infrastructure GIS supporting the development of one or more business process GIS - Diffusion of a corporate GIS takes place in the dispersed scenario. - Diffusion takes place when the purposes served by a module are focused and well defined. - Reinvention of a corporate GIS can be monitored by the outcome of diffusion of the modules of GIS in the focused scenario. These relationships are confirmed by the outcomes of a survey of the State Government of Victoria and a subsequent case study that involves the Department of Natural Resource and Environment of the government. As a result, the hypothesis is validated. (For complete abstract open document)