Within the UK traditional masonry construction techniques are struggling to deliver the quantity and ecological quality of housing required by an ever increasing UK population. This research employs a case study review of a mainstream mixed timber frame and masonry housing development - Green Street, in order to explore the ecological viability of timber prefabrication as an alternative to the established masonry construction methods currently employed in the majority of British housing. Four houses of each construction type in the Green Street development were outfitted with a number of environmental monitoring sensors for continuous monitoring. In addition the study incorporates fabric testing in the form of air permeability testing, Co-heating analysis, thermography, and a life cycle analysis. Building Use Survey, project management and design team interviews and an industry questionnaire form the final part of the evaluation protocol. The study revealed that heating the timber dwellings ultimately required less energy per degree difference between inside and outside temperatures. During the summer the timber housing displays a greater diurnal temperature swing, while on average the temperature remains consistently lower than the masonry housing. The masonry housing was found to be both more air tight and exhibiting a lower heat loss coefficient, despite that, the performance gap between design and reality for space heating is less in the timber prefabricated housing. The life cycle analysis revealed that the timber walls have a lower impact on climate change. BUS methodology results found that construction type had little to no impact on occupants. The design team review highlighted the need for a greater level of prefabrication in timber housing to increase precision and work around a serious skills shortage. An industry questionnaire suggested that timber construction in the UK can often suffer from poor construction practice, predicated by a gap in specialized knowledge. The research concludes that in this instance, the timber prefabrication technique produced dwellings that perform ecologically on par with their masonry counterparts. In answering the research question, the evidence suggests that at this stage the technique would be better employed on a case by case basis and supported by specialists in timber fabrication, rather than implemented as a blanket alternative for existing masonry construction. Already a number of insights from this research have filtered into industry practice and will continue to better inform both industrial and academic partners in their decisions regarding the use of timber prefabrication in mainstream UK housing.

Low energy building methods, and the corresponding economic and environmental aspects, are an important area of consideration in many developed countries. Saudi Arabia characterized by its hot climates and geographical location in a global region renowned for its high energy consumption and carbon emission rates. Consequently, this research aims to foster the development of low energy housing in Saudi Arabia and establish a low carbon domestic design framework for Saudi Arabia that takes into account the local climatic conditions, context and socio-cultural challenges. In order to fulfil the above stated aims, this research establishes a definition system for low energy consumption in kWh/m² for the Saudi Arabian climate. To achieve the aims stated above, a comprehensive, four stage study has been performed. This investigation has attempted to: (a) identify factors resulting in high energy consumption in domestic buildings in Saudi Arabia; (b) identify the weaknesses of housing design in terms of architectural layouts and mass, house envelope design and construction materials used, and on-site renewable energy strategies; (c) establish and develop a low carbon domestic design framework that supports architects, civil engineers and building professionals in the design of sustainable homes for the Saudi Arabian climate, context and cultural requirements; and (d) propose three different, viable housing prototypes employing the established framework, thereby validating that framework through the identification of their energy consumption levels. Each stage of this research utilizes a specific methodology: public survey analysis; site visits and modeling analysis; expert consultation, using the Delphi technique approach; and the validation analysis approach. This study contributes to the body of knowledge within this field by offering a low carbon domestic framework for the design of low energy homes in Saudi Arabia. These findings are broadly applicable to other regions with similar climatic conditions and cultural requirements, such as those in the Middle East and GCC countries. The findings suggest that an energy reduction of up to 71.6 % is possible. Therefore, the system for low energy consumption level standards is suggested as a range between 77 kWh/m² and 98 kWh/m². The comprehensive economic and environmental benefits of these reductions have been analysed and benchmarked against the current situation in selected developed countries.

For reinforced concrete structures subjected to chlorides, carbon dioxide laden and other aggressive environments, corrosion of the reinforcing steel is seen as a global problem. Maintenance and repairs resulting primarily from premature concrete cracking and spalling have an estimated cost running to $100 billion per annum world-wide. The continual demands for greater load carrying capacity of existing infrastructure only exacerbate the problem. In practice, concrete crack width propagation is seen as one of the most important criteria for design and assessment of the long term serviceability of concrete structures. It is therefore economically beneficial to have a fundamental understanding of the growth of the crack width over time so that better informed decisions can be made regarding the carrying out of any repairs. This research attempts to examine the process of concrete cracking and determine the surface crack width of concrete structures under the combined effects of reinforcement corrosion and applied load in both an analytical and numerical manner. In the analytical method, a model for stiffness reduction of cracked concrete has been derived based on the concept of fracture energy and an analytical solution has been obtained. In the numerical method, an interfacial element has been developed to predict concrete crack width under combined effects based on a cohesive crack model in conjunction with finite element codes. To help accurate prediction of crack width in the numerical method, a realistic constitutive relationship for concrete under direct tension has been obtained from the laboratory experiments. It is concluded in this thesis that both the analytical and numerical methods are one of very few available theoretical methods that can predict with reasonable accuracy concrete crack width of reinforced concrete structures under the combined effects of reinforcement corrosion and applied load. This research focuses on concrete cracking caused by reinforcement corrosion and applied load without considering other factors, e.g., weathering, freeze-thaw and chemical attack. Both methods can be used as a tool to assess the serviceability of corrosion affected concrete infrastructure if reinforcement corrosion and applied load are the main causal factors of concrete cracking. For this type of concrete structures, therefore, scientific information can be provided for asset managers in decision making regarding possible interventions. Timely interventions have the potential to prolong the service life of reinforced concrete structures.

Future energy supply infrastructure schemes for the built environment are set to consist of a diverse mix of distributed generation technologies, increasingly stringent local emissions reduction targets, and potentially complex ownership structures. This thesis presents a new modelling method that integrates technical design, green house gas emissions analysis and financial analysis models for new build multi energy vector systems. The model was used to compare and characterise several alternative heating technology options for the carbon constrained design of a generic UK market town residential development. Of the options examined, natural gas combined heat and power based district heating was shown to provide the least cost solution for projects built before 2020. Beyond 2025, electric heat pumps provided the cheapest option in response to the decarbonisation of the grid supplied electricity. The integrated model was used as the basis of an optimised infrastructure design tool. This was applied to determine the least cost energy supply technology mix for a new build community redevelopment scheme at Ebbw Vale, South Wales. It was shown that both the optimal design and corresponding optimal cost is dependent upon the year of build completion for the project and the

The construction industry has been facing immense challenges to move towards more- sustainable buildings with minimum harm to the environment. The building design and construction process is conditioned by numerous sustainability regulations and assessment measures, to promote sustainable construction. These regulations are continuously expanding in their requirements, and incorporating a huge amount of data that needs to be rigorously dealt with, in order to check compliance and asses the performance Building Information Modelling (BIM) promotes the effective information and process integration across the building life-cycle and supply chain. This integration should comply with an increasingly-complex regulatory environment and statutory requirements. The aim of this thesis is to improve and facilitate the sustainability compliance checking process, by focusing on inter-operability between existing methods of compliance checking and building information modelling. This thesis presents a generic approach for BIM based compliance checking against standards and regulations, with a particular focus on sustainable design and procurement. To achieve this, a methodology has been developed to enable automated sustainability compliance checking. This involves (a) extracting regulatory requirements from sustainability-related regulations available in textual format; (b) converting these into BIM- compatible rules; (c) processing these rules through a dedicated rule-based service; and (d) performing regulatory compliance analysis underpinned by the concept of BIM. A semantic extension of the IFC (Industrial Foundation Classes) for sustainability compliance checking has been developed. The outcome of the research was implemented in the RegBIM project and is in the process of being exploited as an online service by industrial organization, the Building Research Establishment (BRE) in the UK.

Cold formed steel (CFS) sigma sections are commonly used as purlins in the construction of modern industrial and residential buildings due to their excellent strength-to-weight ratio. This thesis reports investigations on the structural behaviour of CFS sigma purlins in three different parts of modern roof systems. In the first investigation, the pre-buckling, buckling, post-buckling and post-failure behaviour of continuous CFS sigma purlins near internal supports was studied by experimental and numerical methods. In the second investigation, the moment-rotation response as well as the moment resistance of the sleeve connection of sigma purlins was studied by laboratory tests. Engineering models were developed to predict the behaviour of this connection and a good correlation was observed with the experimental data. In the third investigation, the flexural stiffness and moment resistance of CFS sigma purlins fastened to roof sheeting with large screw spacing was studied experimentally. The purlin-sheeting assemblies were subjected to both downward and uplift loadings, from which different behavioural aspects such as flexural stiffness, failure modes and ultimate load were examined. Test results are utilized to develop design proposals for sigma purlins that codes or standards have not yet covered.

Lessons learnt from the construction industry have proved that knowledge management (KM) can enhance construction projects successfully. The existing KM models and tools may have some problems, which cannot be used efficiently and effectively. This research aims to develop a new KM model that overcomes such problems and provides an effective way for managing knowledge in the construction industry. An extensive review and analysis of KM models has been carried out and a KM model was developed to fill the gaps of previous KM models. Interviews with KM practitioners and a questionnaire survey have been conducted to enhance the KM model. A final KM model has been set to provide an effective solution for successful implementation and application of KM in construction projects. Two case studies in the construction industry have been carried out to evaluate the applicability and validity of the proposed KM model and how it can be used to improve existing KM systems. The results indicated that the proposed model can effectively facilitate the implementation and application of KM in the construction organisations. Recommendations are given to improve the future implementation and application of KM in construction projects.

The supply of adequate and affordable houses is still a big challenge in many developing countries. Governments have sought to use different housing strategies, such as public private partnerships (PPPs), to solve these urban housing problems, but with limited success. The aim of this study is, firstly, to examine the challenges affecting the delivery of HPPP projects in developing countries and, secondly, to propose a PPP conceptual model to address the identified challenges. A mixed-methods approach was used to collect data from various stakeholders involved with housing public private partnership (HPPP) projects. Purposive sampling was used to select the targeted respondents. The quantitative data were analysed through the Statistical Package for the Social Sciences (SPSS 22.0) whereas the qualitative data were analysed by content analysis. This study identified several challenges hindering the success of HPPP projects with the highest ranked challenge found to be: inadequate PPP skills and knowledge. Results demonstrate that PPP can be adopted as an alternative approach; however; the identified challenges need to be addressed for a successful outcome to be achieved. The key contributions to knowledge include: bridging the literature gap as this study is the first that identifies and ranks the HPPP challenges within the developing country context. Additionally, a conceptual model has been developed by adopting (and modifying as appropriate) success factors from international best practice. It is anticipated that the proposed conceptual model, validated by PPP experts, will provide a valuable road map for the successful delivery of HPPP projects in developing countries.

This thesis is about late medieval carpenters, their techniques and their art, and about the structure that became the fusion of their technical virtuosity and artistic creativity: the hammer-beam roof. The structural nature and origin of the hammer-beam roof is discussed, and it is argued that, although invented in the late thirteenth century, during the fourteenth century the hammer-beam roof became a developmental dead-end. In the early fifteenth century the hammer-beam roof suddenly blossomed into hundreds of structures of great technical proficiency and aesthetic acumen. The thesis assesses the role of the hammer-beam roof of Westminster Hall as the catalyst to such renewed enthusiasm. This structure is analysed and discussed in detail. Its place in the milieu of late medieval architecture is assessed, and its influence evaluated. That influence took effect mainly in East Anglia. Thus, early fifteenth-century trends in hammer-beam carpentry in the region are isolated and analysed. A typology of is created, from which arise surprising conclusions regarding the differing priorities late-medieval carpenters ascribed to structure, form and ornament. A chapter is also devoted to a critical review of literature pertaining to the topic.

When used as secondary roof purlins, cold-formed steel (CFS) sections are often attached to trapezoidal sheets through self-drilling screws to form a complete roofing system. The load application points are often eccentric to the shear centre, and thus inevitably generate a torsional moment that will induce twisting and/or warping deformations in addition to bending deflection. The connections between purlin and roof sheeting provide a restraining effect on purlin members by preventing such lateral and twisting movements, and hence have a beneficial effect on the load-carrying capacity. In this thesis the interactional behaviour of CFS purlin-sheeting system have been investigated through the following steps: (1) A F-test is carried out to measure the rotational stiffness at the connections, an engineering-orientated model is developed for quantifying the rotational stiffness regardless to purlin and sheet geometry and loading directions; (2) A set of loading tests on Z- and Σ- roof system are conducted to investigate the impact of rotational stiffness on the overall structural performance, load-carrying capacity and buckling behaviour of the system; (3) Finite element simulations of the existing tests are carried out and successfully validated; (4) Numerical parametric studies are established to study other factors that could affect the rotational stiffness.