This thesis describes an investigation into the phenomenon of air entrainment in vertical dropshafts conveying water from a high level to a lower level. The study initially commenced with hydraulic tests on scale models of a vortex-entry dropshaft arrangement. This subsequently expanded into a more detailed analysis of the mechanisms involved in the air entrainment, rejection and transport processes evident in the early stages of the work. An attempt has been made to define the criteria controlling these three modes of operation in air/ water systems. The physical process of initial entrapment by the plunging water film was researched extensively. The inability to accurately reproduce the bubble sizes in scale models conclusively shows that this aspect is fundamental to the understanding of the problem. A dimensional analysis of the parameters controlling the rate of entrainment in the system was undertaken in the investigations. A number of dimensionless groups were obtained to describe the relationships between the parameters involved in the process. This enables the rate of air entrainment to be predicted in any.system of dropshafts under certain flow and geometrical conditions. The downward passage of air bubbles in water (just one mode of operation in two-phase flow systems) was investigated to establish the air transport capabilities of various flows and hence the air rejection process. An empirical relationship was derived which describes the air void ratio at various discharges and hence enables many aspects of the transport of air bubbles to be studied. A series of values defining the limits of operation of the phases invovled in air entrainment were also identified, e.g. onset of air entrapment and air transport.

There is a growing concern that current levels of economic activity have outgrown the physical limits of the planet. In the face of global constraints, humanity continues to deplete nature, through resource harvesting and waste generation, faster than nature can regenerate itself. The UN World Commission on Environment and Development (WCED) introduced the idea of sustainable development in 1987, with the release of Our Common Future. Sustainable development has since become a powerful and controversial theme, creating seemingly impossible goals for policy makers. Sustainable indicators can be a key mechanism for encouraging progress in the right direction by providing a measuring tool that gives a clearer understanding as to whether sustainability is being achieved. The ecological footprint has emerged as an innovative technique to measure the ecological dimension of sustainability. The research tests the ecological footprint as a tool for guiding humanity towards sustainability. The research establishes whether or not the ecological footprint provides an effective accounting framework for the biophysical services that a given society requires from nature. With Guernsey as the case study, the research investigates whether or not the ecological footprint is a comprehensive tool for local policy decision-making. Considering the methodology of the ecological footprint, its use for time series analysis and the development of scenarios does this. The ecological footprint is also tested for its ability to act as a tool to communicate the ideas of sustainability. In conclusion, while containing some limitations, the ecological footprint is a tool that can facilitate the comparison of policy choices society inevitably must face. At the local level, the ecological footprint is a valuable part of the sustainable indicator tool kit. The use of the ecological footprint as a communication tool for sustainable development is invaluable. It is an indicator that can be understood by the general public and one that links individual lifestyle choices to global environmental problems. The ecological footprint is only an empirical tool and in itself cannot change anything. It is a first step in a process of change and the political will and desire to change must be the driving force. Its great advantage over other sustainability indicators is that it is holistic and makes connections between different activities and impacts. However, the ecological footprint is based on assumptions as the ratios/equations calculated by others. In conclusion, the ecological footprint demonstrates that intelligent rationalisation of means and prudent moderation of ends is the only solution. By providing common ground, the ecological footprint builds bridges between different worldviews and amplifies the resonance between all disciplines working on sustainability.

Despite the constant improvement of project management tools and methodologies the performance of projects is decreasing. Considering the forecast that the volume of projects undertaken will roughly double by 2025 this is a considerable issue for the profession. Therefore this work focuses on the psycho-social relationships in projects, in particular organisational justice (climate) and their impact on performance in order to present an alternative approach to increase project performance and to highlight this under-researched area. Three studies were conducted for the purpose of this work: first, a questionnaire was used to explore the relationships between organisational justice (climate) and different aspects of performance, mediated through antecedents of project performance. The questionnaire produced a final sample of 194 cases and was analysed using structural equation modelling (SEM). Second, focus groups were administered to better understand how organisational justice (climate) effects performance. A phenomenological analysis was conducted to explore the lived experience of the participants. And third, a case study was undertaken to explain how organisational justice (climate) relates to various antecedents of project performance. The case study was analysed using propositions and pattern matching. All three studies revealed that there are significant and strong relationships between organisational justice (climate) and project performance. These relationships are complex and manifold, but it can be concluded overall that the adoption of fair principles and procedures in projects improves the project performance. Based on the triangulation of the three studies an explanatory framework was developed, which includes details on all the different aspects. In essence, this research showed that next to tools and methodologies it is important to pay attention to the psycho-social relationships in projects in order to be able to face the upcoming challenges of the profession.

The aim of this research project is to develop an improved backcalculation procedure, for the determination of flexible pavement properties from the Falling Weight Deflectometer (FWD) test results. The conventional backcalculation methods estimate the pavement layer moduli assuming full adhesion exists between layers in the analysis process. The method developed in this research can predict the interface condition between the wearing and the base courses in addition to the layer moduli, which can be considered an improvement to the existing procedures. A two stage database procedure has been used to predict the above parameters and to facilitate the determination of the deflection insensitive parameters. The need for this improvement arises from the large number of debonding failures which have been reported in the literature between the wearing and base courses, and the theoretical studies which identified the significance of including the interface bonding condition in the analysis process. The validation of the improved method has been carried out firstly by comparing the backcalculated results for ninety theoretical pavements with their hypothetical values, and secondly by comparing the improved procedure results with other well known programs such as WESDEF and MODULUS. Full scale pavement testing using the FWD has been performed and the backcalculated results compared with measured values for the pavement materials. Indirect tensile tests for resilient modulus of bituminous materials were carried out on cores extracted for the pavements, whereas Dynamic Cone Penetrometer (DCP) tests were conducted for the unbound materials. The Backcalculated and the physically measured results correlated well, validating the improved procedure.

The retail sector is a major contributor to the Gross Domestic Product (GDP) of the UK and is one of the world’s most competitive industries. Its development in the UK has seen it expand dramatically and these changes are of particular significance in regard to retailers in traditional town and city centres. The publication of the National Planning Policy Framework (NPPF) in 2012 set out the government’s objectives for town centres. The key strategies from the paper were to promote their vitality and viability by planning for their growth and development as well as promoting and enhancing existing centres. The main focus of the policy however was to promote a ‘town centre first’ approach in regards to new retail development. Liverpool is one of many UK cities who have recently experienced a new inner-city retail development built alongside existing inner-city retail areas, in particular, through the building of Liverpool One. Opened in 2008, Liverpool One was built to not only offer a new retail experience in the city, alongside the established inner-city retail areas, but to also enhance the existing city centre retail areas through retail-led regeneration. The overall aim of this research is to examine the impacts that have arisen in regard to the opening of Liverpool One in particular, the impacts that this new retail development has had on the already established inner-city retail areas. A mixed methods approach was adopted; a questionnaire was developed to investigate existing retailers’ sales levels and vacancy rates and changes of occupation were measured using Goad maps. Semi-structured interviews were also carried out with existing inner-city shopping centre managers. The findings of the research suggest that the opening of Liverpool One impacted on existing retailers and shopping centres through a loss in annual sales, alterations in footfall patterns, fluctuations in vacancy rates, and changes in occupation of retail space. However, the scale of impact varied between retail areas within the city centre and the economic recession at the time of the study may have also been a contributing factor to these findings. This research informed the development of a set of recommendations to be used as a possible industry tool when incorporating a new regional inner-city shopping centre into an existing town or city centre.

The principles of organization theory are applied to the organization of construction projects. This is done by proposing a framework for modelling the whole process of building procurement. This consists of a framework for describing the environments within which construction projects take place. This is followed by the development of a series of hypotheses about the organizational structure of construction projects. Four case studies are undertaken, and the extent to which their organizational structure matches the model is compared to the level of success achieved by each project. To this end there is a systematic method for evaluating the success of building project organizations, because any conclusions about the adequacy of a particular organization must be related to the degree of success achieved by that organization. In order to test these hypotheses, a mapping technique is developed. The technique offered is a development of a technique known as Linear Responsibility Analysis, and is called "3R analysis" as it deals with roles, responsibilities and relationships. The analysis of the case studies shows that they tended to suffer due to inappropriate organizational structure. One of the prevailing problems of public sector organization is that organizational structures are inadequately defined, and too cumbersome to respond to environmental demands on the project. The projects tended to be organized as rigid hierarchies, particularly at decision points, when what was required was a more flexible, dynamic and responsive organization. The study concludes with a series of recommendations; including suggestions for increasing the responsiveness of construction project organizations, and reducing the lead-in times for the inception periods.

No description available.

Green roofs are increasingly being employed as a sustainability feature of buildings. The sustainability approach in building designs requires reducing energy consumption and adopting low carbon energy sources without compromising the increasing expectations of comfort and health levels. Given the wide range of building designs, climates and green roof types, it is desirable to evaluate at the design stage the energy saving impact and other potential benefits from the application of green roofs. Currently, the abilities of building simulation programs to simulate the influences of green roofs are limited. For example, they have limitations in representing dynamic inter-layer interactions and moisture infiltration mechanisms. This research aims to develop a new model for the simulation of green roofs based on the control volume approach and to integrate the model within a whole building energy simulation program. The green roof elements consist of special layers such as plants and soil for which the control volume approach is capable of capturing their special characteristics with regards to the thermal and moisture exchanges. The model has been integrated within the ESP-r whole building energy simulation program. Within the ESP-r, the new green roof model alters the boundary condition of a roof surface on which green roof is constructed. The model development is carried out by a series of steps which include a careful selection of governing equations that describe the thermal and moisture balances in various layers of green roof, the numerical implementation for a simultaneous solution of the governing equations for the whole green roof, algorithm and code development and finally developing the interface with ESP-r. After successful integration, the model results were validated on an experimental test cell, which consists of an approximately 2 m2 planted medium on an insulated box with facilities for thermal, moisture and drainage measurements. The results for the thermal validation were promising with the significant boundary temperature values within a root mean square deviation (RMSD) in the vicinity of 0.5 K, whereas the moisture validation results are found to depend on initial conditions, the lower layers showing an RMSD of approximately 0.05 m3/m3 and the top layer nearly 0.12 [m3/m3]. The model is also able to predict the slowing down of water run-off. A methodology for collecting soil and plant properties which are required to be used along with the program has also been described. Based on the current state of the model and also considering the new developments in green roofs, some suggestions are proposed at the end of the thesis as a continuation of this research.

Building construction industry has significant impact on sustainability. The construction, operation and maintenance of buildings account for approximately 50% of global energy usage and anthropogenic greenhouse gas (GHG) emissions. In recent years, the embodied energy and carbon are identified increasingly important in terms of sustainability throughout building life cycle. Incorporation of sustainable development in building structural design becomes undoubtedly crucial. The effective building design requires smart and holistic tools that can process multi-objective and inter-connected domain knowledge to provide genuine sustainable buildings. With the advancement of information and communication technologies, various methods and techniques have been applied to accomplish the multiple objectives of sustainable development in building design. One of the most successful approaches is building information modelling (BIM), which requires further enhancement of interoperability. The emergence of Semantic Web technology provides more opportunity to improve the information modelling, knowledge management and system integration. The research presented in this thesis investigates how ontology and Semantic Web rules can be used in a knowledge-based holistic system, in order to integrate information about structural design and sustainability, and facilitate decision-making in design process by recommending appropriate solutions for different use cases. A research prototype namely OntoSCS incorporating OWL ontology and SWRL rules has been developed and tested in typical structural design cases. The holistic approach considers five inter-connected dimensions of sustainability, including structural feasibility, embodied energy and carbon, cost, durability and safety. In addition, the selection of structural material supplier and criteria in sustainability assessment are taken into account as well. This research concludes that the Semantic Web technology can be applied to structural design at early stage to provide multi-criteria optimised solution. The methodology and framework employed in this study can be further adapted as a generic multi-criteria and holistic decision support system for other domains in construction sector.

This thesis presents a study of the characterisation of fine aggregates manufactured from waste quarry material and their use in concrete supported by artificial neural network models of the fresh and hardened concrete properties. The reutilization of rock filler, a by-product of the sand manufacturing process, as a soil liming material is explored. A set of tests and techniques were identified to characterise fine aggregates manufactured from quarry dusts via a dry processing system. Granite, limestone, sandstone and basalt manufactured sands and their unprocessed counterparts “feed quarry dusts” were characterised with respect to their shape and texture, grading and quality of fines (presence of clays). The results showed that the reprocessing of quarry dusts improves the particle shape and grading irrespective of rock mineralogy. Plasticised and non-plasticised concrete mixes were developed and the fresh and hardened properties tested. Concrete consistency, compressive and flexural strength is correlated with the fine aggregate characterisation test results. The manufactured fine aggregates showed a higher water demand when compared with natural sand whereas compressive and flexural strengths were enhanced. Artificial neural network models were developed to enable the prediction of the consistency and compressive strength of concrete. These models used the fine aggregate properties and mix composition parameters as input variables and were validated using a separate testing dataset, additional concrete mixes and numerical evaluation. Artificial neural network models were shown to be able to predict fresh and hardened concrete properties based on the fine aggregate characteristics. The excess fillers created in the sand manufacturing process were evaluated for soil liming potential through standard tests and a soil incubation study. The main finding was that materials with high silicate content exhibit a potential for liming, however, a higher dosage is required when compared to the dosage of high purity limestone to achieve the same liming potential.