An experimental investigation of the thermal properties of a variable cavity wall has been conducted with the aid of a Guarded Hot Box (GHB). The main objective of the investigation was to determine the thermal trends of that exist in such a wall at different aspect ratios and internal configurations. In the course of this research effort, attention had initially focused on the suitability of the GHB as a tool for measuring building components of low thermal transmittance. Following the initial evaluation that included computational modelling of the GHB, a series of modifications were employed, which included a series of baffie plates in the Guard box area. Experimental trials have shown that these modifications culminated in a reduced thermal gradient distribution within the box and along the test wall. As a result, the test wall was subjected to a more uniform heat flux and lower peripheral heat loss. A variable cavity wall measuring 1.2m by 1.2m and 0.41m deep was the main 'focus of this study. By means of a moveable brick leaf, the aspect ratio of the cavity wall could be remotely altered during the experiment, thereby allowing immediate comparison of thermal trends without the errors that are associated with building and testing a series of individual walls of different geometric proportions. In particular, this set-up enabled an accurate comparative analysis of cavity aspect ratios over a range of 15 to 30. Lazer Doppler Anemometry (LDA) and thermal measurement on the four surfaces of the cavity wall leafs were the prime means for collating experimental data. Extensive computational modelling complemented the research, which provided important insights both prior to and following the experimental stage. The use of Computational Fluid Dynamics (CFD), while not intended for precise solutions to models of the GHB and cavity wall, was never the less instrumental in establishing trends and expanding the experimental range, once corroboration of experimental results had been achieved. The experimental and computational results show that with successive cavity closure an optimum aspect ratio is reached, where thermal resistance peaks and velocity of the convective flow is minimal. At this aspect ratio, the flow regime was found to be conductive. The main implication of this result is that decreasing aspect ratio beyond this aspect ratio, by widening the cavity, will result in increasing heat losses due to the circulation of convective currents in the cavity. Thus, it was concluded that when convection diminishes, the thermal resistance of the air cavity would rise. Further computational and experimental work on the same wall with an internal partition, corroborated the trends found during the clear cavity experiment. It was found that a centrally placed vertical partition will double the thermal resistance of the wall. Furthermore, the thermal resistance of the partition was found to equal that of one partitioned cavity, raising the possibility of eliminating cavities from wall construction The effect of mortar joints upon cavity walls, at various aspect ratios, was also investigated. Results show that a vertically sinusoidal flow pattern exists in such cavities due to the thermal bridging effect of the mortar joints. The results of this study were used for several recommendations, which deal both with design of cavity walls and Guarded Hot Box design and operation.

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The British Construction Industry has been criticised for many years. Comparisons have shown that construction in the United States, Canada, France, Germany and Australia is cheaper and quicker than present practice in the UK. In the UK the traditional system of construction, separates the two main disciplines of design and construction. The design is carried out by a consultant and the construction is carried out by a contractor. As a result of this the construction industry is suffering from many problems such as design complexity, increasing costs and longer construction duration. This thesis addresses the detail design stage of the design process. Detail design decisions have a significant impact on cost and time. The UK contractors have no important influence at the design stage, because designers do not take adequate and accurate account of construction methods, actual costs and the value of time. The traditional system prevents this involvement. To overcome this problem, constructability was cited as being c, apable of improving project performance. There is, however no clear understanding of why or how to formally incorporate construction knowledge as part of the process of design. The designer could reduce problems for the contractor by being more aware of the construction process and the potential delays and inefficiencies which are often introduced during design. Similarly, the contractor could aid the design by contributing his knowledge of site practices to the designer and improving communications during the construction process. The thesis focuses on integrating construction expertise with the design process at the detail design phase. It explores both the designer's and the constructor's view points, and presents a design process model.

Prompted by the energy crisis in the 1970's, European level fiscal and financial measures encourage energy efficient building design. "Mixed mode" strategies can be employed in buildings with moderate thermal loads, this approach can reduce building energy usage, and by inference, reduce C02 emissions. A mixed mode approach might employ chilled surfaces with displacement ventilation. This thesis investigates the performance and integration of one form of chilled surface design, (a sub-dew point chilled beam), within mixed mode strategies. Sub-dew point chilled beams have a surface temperature that is at or below the zone saturation temperature, this increases the cooling capacity of the chilled beam and consequently produces a latent heat transfer addition due to condensation mass transfer. This thesis describes the sensible and latent modelling approach which models the zone, sub-dew point chilled beam and mixed mode strategy thermal plant response to external disturbances. The thesis describes the use of an Enclosure Comfort Performance Indicator that acts as the objective function for the optimization of the mixed mode strategies with and without the integration of the sub-dew point chilled beam. The implementation of the Complex method for finding the operational optimums of the mixed mode strategy is described, and its effectiveness at finding the optimum solution evaluated. Normalised energy, cost and comfort performance indicators are used to assess the overall performance and integration of the sub-dew point chilled beam for different mixed mode strategies, for the ambient test conditions and for different thermal weights of building construction.

This thesis is concerned with the phenomenon of Rising Damp, which is a complex example of the simultaneous flows of volume (water), heat, solutes and electricity within a porous material. The physical complexity of this natural occurrence has required that the phenomenon be reduced into a series of scientific areas or related topics, which are presented as separate chapters. A full account of the structure of the thesis can be found in the introduction section. The common areas covered in this work are mathematical description of the loss of moisture by damp porous materials (i.e. evaporation) and of the movement of moisture within unsaturated porous materials both in terms of non linear "Diffusivity" type expressions (Chapter Three) or more usefully in terms of non linear "free energy" type expressions (Chapter Eight); capillary suction developed in damp walls. Other less common topics investigated are leaching of soluble materials from the porous matrix and prediction of the consequent increase in matrix permeability to fluid; electro kinetic aspects of Rising Damp; coupling of transport processes within porous materials. Several of the topics discussed in this work are common to several scientific disciplines giving rise to a 'looseness' and 'multiplicity' of nomenclature. To overcome this problem, particular care and space has been devoted to explaining the terminology used in this work, which is especially useful to readers who are unfamiliar with this area of study.To conclude, the thesis covers the essential aspects of Rising Damp and, as such, it may be used as a platform from which the phenomenon can be investigated more comprehensively

This thesis describes the development of a knowledge based system which encapsulates some of the expertise used by a number of experienced construction planners for planning the construction stage of low rise house building projects in the U.K. The general objective of the research was to investigate the feasibility of using knowledge engineering for developing models of construction planning expertise, which could be employed for tackling some of the existing knowledge bottlenecks in the construction industry. The resulting system can be described as a knowledge based framework designed for supporting the decision making process involved in planning house building at a tactical level. One of the main features of this framework is its ability to cope with incomplete information. The knowledge acquisition process involved both the elicitation of knowledge directly from experts, and the analysis of construction plans from several past housing developments. The model was implemented on an expert system shell called LEONARDO Level 3, which runs in any standard IBM-PC micro-computer or compatibles. The evaluation of the system focused on the validity of the model, i.e. the degree at which the outcomes of the system resembled the outcomes of the human expertise being modelled in the knowledge base. A prescriptive method of validation was devised specifically for this study, involving both experts that had provided expertise for the system, and external experts.

Value Management (VM) is an organised effort directed at analyzing the functions of systems, supplies, equipments and facilities, for the purpose of achieving the required functions at lowest overall cost, consistent with requirements for performance, including reliability, delivery, maintainability and human factors. This structured method can also be successfully used to define the scope of a project. In the UK, the awareness of the tremendous potential and benefits of applying VM to construction projects has made some clients eager to apply this technique to their projects. There are, however, a number of problems which inhibit the use of this advanced technique in the construction industry. Qualified VM specialists, for instance, are very scarce within the industry, it is often difficult to find them to undertake proper VM studies. This research therefore aimed at exploring the feasibility of building a Knowledge-Based System (KBS) to facilitate VM implementations in the design stages of a construction project. A demonstration system has been successfully developed to illustrate the facilities which would be available to potential users in a fully developed system. A method of allocating project cost against functions of the project specified by the clients has been developed, which could expedite the processes of clarifying clients' brief and ensuring good value for money by cutting unnecessary costs and enhancing required functions. The research has also explored how KBSs can be effectively applied to "open-ended" decision-making problems in which new options may be generated during each session with the system, i.e. the study considered the possibility of letting users extend and customise the knowledge base. The system has been described as a "satisfactory and very promising system" by the UK industrial specialists.

The aim of this thesis is to answer the two research questions: how can design for manufacture be applied during building component design and building design?; and how can the application of design for manufacture be successful in improving the productivity and quality of building component production and building construction? These two questions emerged during exploratory research focused on the use of design to improve construction industry productivity and quality. Subsequent review of manufacturing literature revealed that the two key principles of design for manufacture are standard production design improvement rules and standard production design evaluation metrics. Review of construction literature, and a survey involving over one hundred and fifty industry practitioners, revealed that, whilst rules and metrics for building components and buildings do not currently exist, there are no fundamental reasons why they could not be developed and applied successfully. These findings led to the generation of the research hypothesis: design for manufacture principles can be applied successfully to building components and buildings. The research hypothesis was tested by two interventions, action research within a private business which manufactures and installs building components, and a case study with a multi-national company which designs and constructs buildings. These interventions resulted in significant business benefits. Further, they confirmed that it is both technically feasible and economically viable to apply rules and metrics to building component design and building design, and that doing so can improve the productivity and quality of building component production and building construction. Following analysis of research findings, strategic plans were developed for the successful application of rules and metrics. These were validated through interviews with senior construction industry practitioners. Contributions to knowledge include the strategic plans for successful application of rules and metrics. These cover the full range of organisations working in the construction industry and, together with the detailed descriptions of the interventions, offer practical guidance for industry practitioners seeking to improve productivity and quality. The research also makes a contribution in the area of research methodology. It has shown that threats to research validity in the construction industry can be counteracted by applying a quasi-experimental perspective to action research interventions and case studies.

Construction companies are operating within an increasingly competitive environment. Work often has to be tendered for on a very low profit basis. If the tender is too high, work is lost. If too low the contract may be won, but the job completed at a loss, unless more effective working methods can be found. Plans are used throughout the construction industry to allocate resources and schedule work. Yet, the planning tools used; Gantt chart, PERT and Queuing theory to name but a few, represent jobs as if they are static in duration, which in the complex, dynamic construction environment are clearly inappropriate. The EPSRC fuelled interest in developing a simulation methodology by suggesting that the construction industry could be considered similar to the traditional manufacturing industry. The manufacturing industry faced similar production dilemmas, work was completed but using inefficient resource configurations, causing bottlenecks, increased work-in-progress leading to higher costs. To reduce number of problems the manufacturing industry sought to utilise and develop a planning technique that had the capacity for modelling the dynamic nature of the industry. Discrete-event simulation enables the problems associated with manufacturing to be anticipated and minimised, as opposed to constantly fire-fighting. Since using simulation has accrued such impressive benefits within the manufacturing industry it is therefore not without credence to believe that the construction industry could also obtain saving from embracing this management tool. Simulation has been applied to model a number of scenarios within the construction industry. Similarities between the applications were sought and an area for further development was identified. A problem was modeled using the most frequently encountered simulation paradigms found in the manufacturing and construction industries, 'Activity cycle' and 'Process based'. Of the two methodologies, 'Process based' was selected for the development of further models. A conclusion drawn from the research is that simulation is not being utilized within the construction industry due to the perception that it requires an excessive use of resources. The research project identified that the model building process may be simplified through the development of generic simulation modules. These generic modules enable a simulation model to be developed quickly and easily by a non-simulation practitioner. The generic modules can be connected to represent the layout of an earthmoving operation. A host of scenarios can thus be modeled with the minimum of time and effort. To ensure that only significant data and process logic was collected and included within the modules the experimental methodology factor analysis was employed. Using this experimental technique, the relationship between and significance of ten different factors were established. Further experiments were performed on the most significant factors establishing an appropriate level of detail for those factors. It was beyond the scope of this thesis to develop modules for every conceivable construction process. Therefore, a methodology is given documenting the development of the chosen construction processes.