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In Europe, clay roof tiles are manufactured by pressing in 'open' moulds whereas in South East Asia 'closed' moulds are commonly used. The European products are more complex, having a greater degree of detail. Closed mould pressing could, however, be advantageous as it would minimise scrap recycling but the products would need to have equivalent or superior durability to existing tiles. The aim of this work was to investigate the feasibility of using a closed mould for the manufacture of European tiles by examining the relationship between the type of pressing and subsequent durability, in terms of resistance to repetitive freeze-thaw cycles. One specific clay type, the Marseille rose blend, was investigated over a range of forming water contents. Preliminary data relating to plasticity and friction were obtained through an empirical (Pfefferkorn) plasticity test, uniaxial compression of cylinders and friction ring experiments. Clay cylinders containing 16-21 wt % water were deformed at a compression rate of 240 mm/min. The yield stress was found to increase with decreasing moisture content. The plastic ranges of the stress-strain curves were well represented by a plastic deformation equation of uniaxial compression under sticking friction conditions. A laboratory-scale pressing rig was designed to make profiled specimens which would reproduce the essential features of a European tile. Comparison of the microstructures of the laboratory and factory samples showed that there was sufficient resemblance to validate the replication of the Marseille products in the laboratory tests. Bats of three moisture contents of 16.4, 18.4 and 20.6 wt % and different geometries were pressed in open, partially closed and closed rubber lined resin moulds in a mechanical testing machine using a cross-head speed of 240 mm/min. This was lower than a typical pressing operation but the speed of pressing had been found to not be a significant variable over the range commonly encountered. Clay was trapped in the features as the mould closed and flowed mainly within the flat part of the samples during pressing. For the open and partially closed moulds excess material was extruded through the gaps at the sides, a process referred to as flashing. The shape of the load-displacement curves was characteristic of the stages of the pressing process. The stress-strain curves for the pressing in open moulds showed good qualitative agreement with the results from uniaxial compression of cylinders. The open porosity of the samples after firing was strongly related to the forming moisture content of the clay with the open porosity increasing with increasing water content. Comparison of extruded bats and pressed bars showed that the influence of the pressing processes was not significant. Likewise, in freeze-thaw testing, the effect of the moisture content was again the overriding parameter, with acceptable durability always being obtained from the lowest open porosity samples. Given the marginal differences, the pressing processes investigated in this study were assumed to be equivalent in terms of the quality of the samples produced. Thus, closed mould pressing is feasible but does not lead to product improvement and hence may not be economically viable.

An area in the northern part of the Moine Thrust Zone of Loch Eriboll and in the NE side of Loch Hope, NW Scotland, has been mapped in the scale of approximately 1:10,560. Detailed measurements have beea made of structures such as foliations and lineations and these have been studied and analysed geometrically in terms of their relative age and the consistence over the whole area. The mapping has also traced the intricate pattern of thrust faults which trend roughly NNE/SSW. These thrust zones delimit different nappes and the deformation aspects of these faults indicate that the rheology of the rocks suffered changes during the thrust belt evolution. The easternmost major thrust zone is considered to have been developed first and clearly shows the characteristics of a ductile deformation zone. This zone is interpreted here as the Moine Thrust Zone, sensu stricto. A conspicuous mylonitic zone lies beneath and trends parallel to the Moine Thrust Zone and is limited in the west by a thrust which carried the mylonites onto clearly non mylonitic rock. The width of the mylonitic zone varies from Loch Hope in the north to the SE end of Loch Eriboll. This width variation is interpreted as due to thickening of the mylonitic zone by effects of folding and also due to the different deformation bands which anastomose and die out. Closely spaced cross sections, transverse to the extension of the belt of deformation are illustrated and discussed. Strain analyses were carried out in two different domains of the mapped area. In the southern half of the area, where the frequency of folds is high, the distribution of fold hinges in sheath or curvilinear folds were used as strain indicators. Models, numerical methods and computer programmes for this strain evaluation have been thoroughly investigated. A detailed description of the methods used and tests performed with the constructed computer programmes is given. The results are analysed in conjunction with the land geology and structure. For the northerly half of the mapped area, strain estimations have been made using the grain shapes of the Paleozoic quartzites which are common in the two lowermost nappes. A new method for fitting the strain ellipsoid using three orthogonal ellipses was devised. A computer programme making use of this method was constructed and applied to the existent data. An alternative solution is also presented for the case where the fitted surface is not an ellipsoid. The strain results with the above methods are compared with those obtained using other published programmes and methods of strain estimation. . Microtextural variations in the Paleozoic quartzites of the northern domain have been studied. A detailed textural description and correlation is made between the textures and the available information on the deformation intensities shown by the quartz grains. An increase in the measured strain intensity is generally accompanied by an increase in the amount of recrystallized new quartz grains. These facts are consistent with the geology and structures of the nappes where sampling was done. Paleostress estimates using recrystallized grain sizes have been performed at 31 localities in the Eriboll and Hope areas. The methodology of particle-size estimation is described in detail. The necessity for a standardization in the methods of particle-size measurement is emphasized with examples. The estimations of the differential stresses are greater in zones of greater relative deformation intensity. Although there are limitations and some adverse criticisms on the reliability of these paleostress estimates, the conclusion reached by this study is that they form a pattern that fits well with the geology and structure of the investigated area. Rheologic considerations on quartz deformation constitutes the last part of the thesis. Deformation maps were constructed for this study using ranges of probable differential stress and the measured size of the newly recrystallized quartz grains. It is concluded that strain is predominantly accommodated by internal mechanisms operated by dislocation processes. It is also inferred that the operative strain-rate for the deformation conditions of this area, is between 10-13s -1 and 10-12s-1.

Bearing pads undergo deformation while under service loads of any bridge. The pad translates the load to the support structure, and allows for movement of the superstructure. The deformation of bearing pads is an important element to consider when designing both the super and sub structures of the bridge. The Federal Highway Administration provides a guide for the design of steel brigdes, and Step 6 of this guide covers the design of bearing pads. The purpose of this study is to analyze the deformation of bearing pads using a finite element analysis software. This study will analyze two separate models, one ignoring the steel plates in a bearing pad and ignoring friction, while the other will take into account the steel plates as well as friction during the analysis. Once the linear analysis is run the models that are built can be compared with the FHWA design examples to compare and verify the results. This will facilitate the possible improvement of current design examples and allow for a more realistic result for designers to use. This study also looks at the internal testing results provided by a bearing pad manufacturing company. These internal results will provide a real world model for the linear analysis models to be compared to as well. Once all factors are taken into account, the validity of the current standards can be evaluated.

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Convergent continental margins are regions of intense deformation caused by the interaction of oceanic plates with continents. The spatial extent of deformation is broadly commensurate with the specific time scale of the causative phenomenon. For example, subduction-related short-term deformation is limited to <200 km from the margin, whereas long-term plate convergence cause deformation over ∼1000 km landward. Deformation is thus manifested in multiple ways, with attributes depending on the scale of measurement. In this thesis we investigate the use of two geophysical approaches in the study of deformation: 1) The analysis of potential-field anomalies to derive estimates of the elastic thickness (Te) of the lithosphere, and 2) The structural study of past and present subduction systems using seismic observations and modelling. Both approaches involve the development of appropriate methodologies for data analysis and modelling, and their application to the western Canadian landmass. Our findings are summarized as follows: 1) We develop a wavelet-based technique to map variations in Te and its anisotropy; 2) We show how a step-wise transition in Te and its anisotropy from the Cordillera to the Craton is a major factor influencing lithospheric deformation; 3) We implement a waveform modelling tool that includes the effects of structural heterogeneity and anisotropy for teleseismic applications, and use it to model the signature of a fossil subduction zone in a Paleoproterozoic terrane; 4) We use teleseismic recordings to map slab edge morphology in northern Cascadia and show how slab window tectonism and slab stretching led to the creation of the oceanic Explorer plate; 5) We use seismic signals from the subducting oceanic crust to calculate elevated Poisson’s ratio and infer high pore-fluid pressures and a low-permeability plate boundary within the forearc region of northern Cascadia. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

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