This thesis investigates the design of masonry shell structures. Design is understood to involve two main processes; the first one is the specification of shape, form, and thickness, and the second is the justification of such choices through the analysis of its behaviour. The thesis is therefore introduced by an extensive literature review of, first of all, the relevant material properties, such as strength, stiffness, anisotropy, and bi-axial stress states, as well as of some interesting construction techniques, based on minimal or no formworkthe premise being that the contemporary adoption, or otherwise, of masonry shells as a feasible structural solution depends on the "economics" of the construction process. The analysis of the strength of masonry arches and shells is reviewed extensively, with considerable emphasis given to the validity of the application of limit analysis to masonry shells, in view of the presence of finite friction. Techniques for the form-finding of shells and for the optimisation of such forms, are then studied, and a finite-element technique developed for the finding of membrane thrust surfaces for shells incapable of carrying tension (as well as having possibly orthotropic properties). The technique is based on the solution of the partial differential equation relating shape, stress and loading, given a specific loading regime, and specific boundary conditions. The stress distribution, satisfying the given boundary and material conditions, is obtained, not on the basis of a trial-and-error approach, as is often the case, but on a plane stress analysis of the horizontal projection of the shell. The resultant shape hence automatically satisfies the boundary conditions. Various examples of the results of such method are given.

The problem of determining an appropriate procurement form for the management of a construction project has been surrounded by controversy and strongly held opinions. The work reported here attempts to indicate some rational basis for choice in this decision by identifying those factors which significantly affect project performance, with particular reference to the distinctions between design build and traditional procurement forms. Two basic propositions are addressed by the work. The former is that design build forms perform better than traditional forms. This view is based on the conventional, construction industry view of the factors which affect performance. The latter is that contextual factors and the management and organisation of the construction process are the major determinants of project performance. This view stems from the application of management theory to the construction process and takes into account more and diverse variables than the conventional view. The factors which affect construction project performance are identified by reviewing three basic areas which are fundamental to the research. The first is the construction process and the way it has been treated and analysed in the past, which has been based around the traditional form of organisation. The second is the perceptions held concerning the design build process and how this procurement form has developed over recent years. A taxonomy of design build organisations is presented. Finally, the literature concerning project management, in general and specifically applied to the construction process, is reviewed and those factors which have been identified as affecting project performance identified. Following on is a review of performance measures which have previously been adopted. Based on this review a number of measures are chosen to compare performance (a mixture of objective and subjective measures). The foregoing leads to the situation where two research models are proposed and tested, by the formulation of related hypotheses, in two separate phases of the research process. A sample of 47 projects was used in the initial phase of the work and this was followed up by 27 detailed case studies in the subsequent phase. The data collected are analysed using partial correlation analysis as the principal analytic tool and the main results are reported below. The primary conclusion to be drawn is that procurement form is not a good predictor of performance. In general, the management, organisation and contextual variables are found to be more strongly associated with performance. Specifically, increased client complexity and dependence are found to be associated with reduced performance, as are increased project complexity and uncertainty. Document certainty and completeness and the degree of competition in letting construction works are all factors found to affect performance. Familiarity and differentiation are organisational factors which are found to be strongly associated with performance. Finally, it is shown that different procurement forms can be located on a structure grid and that those organisations which are appropriately located are associated with higher levels of performance.

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This study is concerned with the convective heat transfer, due to the action of the wind, from the upper surface of roof mounted flat plate solar collectors. The ability to predict the quantity of heat transferred from a collector, in this manner, is necessary in order to facilitate the evaluation of the overall efficiency of a collector panel. Previous methods of determining this convection coefficient have generally relied upon extrapolations of small scale wind tunnel results to full-scale values. The validity of these methods is questionable, and it was found that there was a lack of full-scale data relating to the convection coefficient from the upper surface of a flat-plate collector. It was also found that no systematic attempt to relate model results to full scale values had been made. Full-scale experiments have been performed to evaluate the convective heat transfer coefficient, h, from the upper surface of a roof mounted flat plate. The convection coefficient was found to be dependent upon the wind speed as measured above the roof ridge line, V 6R, and to some extent upon the direction of the prevailing wind, G. Relationships between h and V 6R are presented, as are relationships between h and VH (the wind speed measured at the mid-panel height) and h and V 10 (the meteorological 10m wind speed). Small scale wind tunnel experiments were also performed. This was in order to assess the potential of using wind tunnel model results to predict accurately full-scale convective heat losses. These experiments showed some qualitative agreement with the full-scale tests. However, extrapolation of these model results to full-scale values rendered heat transfer coefficients in excess of those found in the full-scale work. Therefore the use of previously derived full-scale results from wind tunnel studies must be treated with caution. It is suggested that the full-scale results, presented here, represent a more satisfactory means of evaluating the convective heat transfer from the upper surface of roof mounted flat plate solar collectors.