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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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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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)
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ItemDendroclimatological investigation of river red gum (Eucalyptus camaldulensis Dehnhardt)( 1995-02)This thesis examines the growth ring structure of Eucalyptus camaldulensis Dehnhardt and investigates links between ring features and the climatic conditions under which growth took place. Samples of E. camaldulensis from the Barmah Forest (near the River Murray in northern Victoria) were used in the study. E. camaldulensis growth is linked to periodic flooding, and the Barmah Forest contains sites that are frequently flooded. Wood samples were obtained from sites subject to different average flooding frequencies. Trees used in the study grew out of natural regeneration in the 1920’s and 1930’s and from regeneration trials in the early 1960’s. Initial investigation of E. camaldulensis samples revealed ring-like features that were able to be traced on samples by eye. Microscopic investigation showed that there existed considerable variations in the properties of individual rings at different positions on the samples, and that the boundaries between rings were often indistinct.
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ItemA methodology for estimating yield from small ungauged rural catchments( 1991)An estimate of streamflow yield from ungauged catchments is often required by water management Authorities. A survey of Authorities indicated that the techniques used in computing streamflow yield from small ungauged rural catchments were limited to a range of empirical methods with questionable accuracy. There is clearly a need to develop a more reliable simplified methodology. The proposed methodology is based on the calibration of a rainfall-runoff model using a number of gauged catchments and the development of regression relationships between catchment physiographical characteristics and model parameters. The parameters are then used in conjunction with the rainfall-runoff model and meteorological observations to estimate streamflow yield from ungauged catchments. The 2-parameter rainfall-runoff model (MOSAZ) was developed only after a detailed study of actual evapotranspiration and parameter optimisation. Morton's model, based on Bouchet's complementary theory, proved to be an adequate method to calculate actual evapotranspiration from catchments. The model was tested with data from forested, native pasture and irrigated wheat catchments. The model is considered to be superior to methods based on pan evaporation as the actual evapotranspiration predicted using Morton's model is independent of the catchment cover and the prevailing soil moisture conditions in the catchment. A number of optimisation techniques based on direct search and gradient methods were tested for accuracy. From the methods tested, the pattern search and the Gauss-Marquardt algorithms proved to be superior. The interaction between satisfactory compliance with simple least squares error assumptions and the goodness-of-fit between observed and predicted streamflow was also studied. An important feature of the proposed methodology is the use of a multi-dimensional plotting routine termed Andrews' curves to separate the 184 catchments in the study region into a number of hydrologically homogeneous groups based on catchment physiographical characteristics which are related to MOSAZ model parameters. Regression relationships between MOSAZ model parameters and catchment physiographical characteristics were developed for one homogeneous group of catchments based on information from 17 catchments. The developed regression relationships were used to calculate streamflow from four test catchments to demonstrate the applicability of the developed methodology. As the results appeared promising, it is possible to extend the developed methodology to other homogeneous catchment groups.
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ItemThe behaviour of salinity and density stratified flows in the Wimmera River, Australia( 1994)A quantitative understanding of the behaviour of salinity and density stratification in the Wimmera River is developed using a combination of field, laboratory and numerical modelling techniques. The Wimmera River, which is located in north-western Victoria, Australia, is a saline stream with a seasonal and highly variable flow regime. Large salt fluxes enter the Wimmera River as a result of surface water inflows from the upper catchment and groundwater inflows in the upper and lower reaches of the stream. During periods of low and zero flow, a series of long deep pools exist along the river, particularly downstream of Horsham. Inflows of saline groundwater accumulate in scour depressions within these large pools and a series of density stratified or saline pools results. Small flows of saline and fresh water down the river can also lead to density stratification. Larger flow events lead to destruction of the density stratification. A model of flow and salinity in a 200 km reach of the Wimmera River is developed using the MIKE 11 model (DHI, 1992a; 1992b). MIKE 11 solves the St Venant equations for gradually varied, unsteady flow and the Advection-Dispersion equation for solute transport. A time-series data base of discharges and salinities for all surface water and groundwater inflows to the river is developed. This was an important step in the model development due to the existence of a significant number of ungauged tributaries and the importance of groundwater as a source of salt. Stream channels are specified in MIKE 11 by defining a channel network and specifying a series of cross-sections along each channel. The channel morphology of the Wimmera River is studied and a methodology for characterising channel variability is developed. It is shown that the Wimmera River channel can be divided into two statistically different channel types which are characterised by a typical length-scale of several kilometres. Using the above analysis as a basis, a stochastic model of stream channel cross-sections is developed for the Wimmera River and used to infill the existing cross-sectional data. The hydraulic implications of along-channel cross-sectional variation are investigated numerically. A one-dimensional model of the Wimmera River is calibrated and tested. This model is applicable to in-bank flows and their associated salinities. The model adequately simulates the routing of water and salt down the Wimmera River. Variations in salinity associated with flow events and the seasonal variation of salinity are reproduced. Field and laboratory investigations of density stratified pools are described. Density stratified pools form as a result of saline groundwater inflows when the stream discharge is less than 200 - 300 Ml/d. The rate at which the stratification develops is quantified for four field sites. Saline water is mixed from density stratified pools during flow events. The mechanism responsible for most of the mixing involves a thin outflow of saline water up the downstream slope of the scour depression. Turbulent entrainment is also responsible for some mixing. During the autumn, convection associated with surface cooling can also mix some density stratified pools. A model of individual density stratified pools, known as Salipool, is developed and tested. Salipool is applied to four density stratified pools in the Wimmera River. A generalised calibration of the mixing relationship incorporated in Salipool is suggested. This generalisation is based on bend sharpness. It is hypothesised that bends have a significant impact on mixing of density stratified pools due to their effect on the vertical velocity profile and the direction of nearbed currents. Salipool is used as a basis for modifying MIKE 11 to incorporate the effect of density stratification.
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ItemModelling hydrologic and climatic controls of closed lakes, western Victoria( 1995)To quantify changes in water level and climate, a water balance model, calibrated using historical climate and lake levels, is used to construct a detailed 16,000 year record of precipitation/evaporation (P/E) ratio for three closed lakes in western Victoria. Lakes Keilambete, Gnotuk and Bullenmerri are maar lakes situated in western Victoria, 200 km W of Melbourne. With high lake/catchment ratios, these lakes are sensitive to atmospheric conditions affecting water balance. Their levels are controlled by direct precipitation and evaporation; groundwater (baseflow) is a minor contributor to the water budget. Previous studies have constructed detailed records of lake levels and palaeosalinities, providing a continuous hydrologic record from 16,000 years ybp to the present. The lakes were observed at high levels by early European settlers but since 1841, waterlevel has undergone the most rapid and sustained decline recorded for the Holocene. Regional meteorological records are used to construct climate series representative of the study area from 1859-1990. Regional homogeneity is demonstrated between the study area and climate stations elsewhere in southern Victoria, South Australia and Tasmania. Climate change recorded at the lakes is therefore indicative of regional climate. No evidence of climate change is found early in the instrumental record, but a statistically significant increase in of 0.3 °C in temperature occurs after 1960. Evaporation is calculated using Morton's Complementary Relationship Lake Evaporation model, utilising long records of air and dewpoint temperature and sunshine ratio. The model calculates water budgets from rainfall, evaporation and baseflow. Baseflow is calculated from the infiltration rate which is derived from modelled soil moisture. Baseflow is optimised for each lake to reproduce the historical fall in lake level. The equilibrium climate for the pre-European lake level is modelled as a P/E ratio of 0.94-0.96, compared to the current ratio of 0.79-0.80. The historical fall in all three lakes preceded the period of instrumental climate measurement and major land-use changes. It is therefore ascribed to a natural climate change. Equilibrium and non-equilibrium modelling of lake water levels have produced detailed estimates of P/E ratios, demonstrating wide climatic fluctuations during the Late Pleistocene and Holocene. Holocene P/E ratios vary from 0.77-0.80 in the early and late Holocene to > 1.10-1.20 from 7,000-5,500 ybp. Late Pleistocene P/E ratio varied between 0.70-0.80. The resultant record enables precise estimates of P and E to be determined if independent estimates of either variable can be supplied. It provides a detailed view of climate throughout the Holocene and is of special relevance to continental and hemispherical climate records. Further information on palaeolake levels from the study lakes and other related maar lakes will permit the construction of an even more detailed record of P/E ratio for the Holocene. With other long records from the region, it will provide a highly detailed record of climate change in south-eastern Australia, dating from the late glacial period. The study lakes also show great potential for monitoring future changes in P/E ratios, particularly precipitation change.