Accelerating and mineral admixtures, one of the major ingredients in concrete, are primarily used to modify the properties of both fresh and hardened concrete. Within the scope of this thesis, there were four types of cements having almost identical fineness. The mixes were prepared by using natural pozzolan, blast furnace slag and limestone conforming to TS EN 197-1 and two types of accelerating admixtures, namely triethanolamine (TEA) and calcium formate (CF). The effect of set accelerating admixtures with different cement types on the setting time, water demand and compressive strength has been analyzed by an experimental study in accordance with relevant ASTM standards. Finally, it has been observed that the amount of the accelerating admixtures used is suitable because of their effects on the water demand, setting and strength. Due to the density difference of mineral admixtures and clinker, the normal consistency and 110% flow water content should be considered on a volumetric basis. The effectiveness of the accelerating admixtures on the normal consistency water, 110% flow water content and setting time depends on the type and amount of mineral admixtures. The increase caused by CF in the normal consistency and 110% flow water content is higher than that by TEA. The accelerating effect of TEA and CF on the setting times is more significant for cements incorporating 6% mineral admixture. The effects of accelerating admixtures on the compressive strength change with specimen age, type and amount of mineral admixtures. Generally, for all cement types, early age compressive strengths increase with the increase of TEA, however long term strengths increase by increasing CF.

Due to its complex nature, risk and uncertainty are more widespread in construction industry than many other industries. Aiming to ensure that all project objectives are met, risk management is considered as a critical success factor for construction projects. The core elements of risk management are now known and used by many organizations. On the other hand, as declared by Project Management Institute (PMI), the ability to measure the effectiveness in managing risk is one of the most important areas that risk management needs to be developed in. Designed to assess the capability of a project or an organization in a particular area, a maturity model aids in determining strengths and weaknesses, and to target improvement strategies accordingly. Several maturity models have been developed for the area of risk management and furthermore, an attempt to adapt a generic risk management maturity model to the construction industry was specified from the literature. All in all, when examined, it was seen that most of these models outline the topics to be investigated in a maturity assessment and provide guidance in terms of content. It was believed that a practical approach was needed and the diagnostic characteristics of these models should be enhanced. Therefore, the aim of this study was to propose a construction risk management maturity framework, together with an easily applicable and effective questionnaire. To achieve this aim, six outstanding risk management maturity models were examined, and the proposed model was further supported with construction-specific attributes such as construction supply chain issues. The applicability of the model was tested through case studies conducted with five large scale Turkish construction companies. The results were evaluated and interpreted for each company and the gathered data were further investigated through statistical tests for certain comparisons. Finally, the questionnaire was revised with respect to the feedback received from the case studies.

This is the report of a Life Cycle Assessment (LCA) study on some masonry wall types. As the starting point, literature on masonry materials, techniques and possible end-of-life scenarios were examined that are needed for the formulation of a LCA study. Prevalent masonry types were detected as fired clay brick, AAC block, natural stone, mud brick as well as prevalent end-of-life cases as landfill, reuse and recycling. Additionally, an overview of the literature on Environmental Impact Assessment (EIA) was presented in order to detect a framework for the structure of a LCA study. After the collection of all needed information, several possible life cycle scenarios were formulated in a realistic manner for each stated masonry type. Obtained information was applied to a LCA evaluation software product named SimaPro life cycle inventory software (PR&eacute / Consultants, 2012). By means of the software product, general scores of environmental impact for all alternatives were obtained. Besides analyzing and comparing the scores, basic reasons behind the results were discussed in terms of similarity and difference. The results reveal that when the requirements shaping the wall are clearly described, the most and the least environmental friendly wall types are detectable. During the study two main scopes, such as commonly used wall thicknesses and thicknesses for thermal insulation were described and several types of walls with life cycle alternatives were labeled as the most or the least harmful to nature. To conclude, although it is not reasonable to point out one type of masonry as the least harmful one for any cases, the conditions of each case detect the most and the least v harmful type of masonry walls. Nevertheless, the relatively low environmental impact of mud brick masonry is striking. Therefore the environmental friendly aspect of mud brick masonry is underlined &ndash / one more time- by the results of this study.

UK statistics have shown that a significant percentage of fatalities in fires have suffered from some kind of disability. In this context 'disability' relates to a person's physical or mental condition that impinges on their ability to react and move promptly in an emergency. Various evacuation modelling techniques are being adopted to study the movement of occupants during emergencies since the exposure of people to fires for experimental purposes is unethical. However, many evacuation models have ignored the effects of disability on escape potential and therefore tend to predict optimal evacuation times. Moreover, whilst providing some valuable insights into certain factors affecting occupant movement, current models are generally presented in isolation and fail to define a general framework for designing solutions to fire safety engineering problems. The purpose of this research programme was to develop a more general methodology for predicting evacuation times of mixed-ability populations. This was made possible through the development and use of a novel concept of evacuation peiformance index (EPI), which is the relative ease of evacuating a disabled person compared to an able-bodied person, founded on a consideration of the effects of disabilities and mobility aids on evacuation times. The author shows how this concept relates three aspects of fire safety, namely, individual characteristics of disabled occupants, the amount of assistance they require, and building design and environmental factors. She contends that the evacuation peifornzance index of a class of individuals is primarily dependent on these three categories. Experimental data to verify the above claim was collected from careflully monitored evacuation drills involving a group of disabled people. Their EPIs were determined along a pre-defined route from which their evacuation times were calculated. Comparisons between predicted times using the EPI concept and measured times from alternative empirical data were seen to be in reasonable agreement. An iterative design procedure is also suggested; one that is capable of predicting worst possible evacuation times by incorporating measures of EPI and escape route dimensions and details. The EPI concept provides fire safety engineering with a logical design philosophy, which is flexible and easily comprehensible. It endeavours to increase understanding of evacuation of disabled people, and provide a simplified mechanism for fire safety design and planning of evacuation procedures.

Over the course of the last few decades, most developing countries, including Libya, have experienced a rapid economic growth and associated increase in population. This growth has led to a substantial increase in the implementation of contemporary housing programmes and urbanisation in the form of new districts, mainly influenced by western models, although the use of some traditional forms continues in hybrid designs. Traditional housing gains its name due to its close relationship between the functional needs of the occupants, the culture, the climate, and other aspects of the living environment. In contrast contemporary designs of houses have appeared only recently in State development plans and projects, and have begun to show some shortcomings in functionality. Thus, this study aims to investigate and understand the reason for these shortcomings and to make recommendations for future housing policies in the state. The design of traditional and contemporary housing in Tripoli-Libya is analysed in terms of suitability for cultural, social and climate conditions. This is explored through contextual research based on a review of the literature, concentrating on the development of housing design in Libya since 1885, including all the factors that have influenced Libyan housing design. The satisfaction level of the occupants living within both types of housing has been explored in three representative case study areas in Tripoli. Residents' views on their satisfaction with their house were sought through questionnaires. Interviews were also conducted amongst government officials and design professional concerned with housing design and implementation programmes to understand professional opinion on the quality of traditional and contemporary housing. The main conclusions drawn from the research emphasises the importance of social and cultural factors, climate conditions, and local building materials, as they all play an important role in designing any house and are important to the level of satisfaction of users. Regardless of the advantages of the contemporary housing used in the case study areas in terms of space and access for motor transport, most respondents were dissatisfied with their new houses in terms of privacy, climate condition, and building materials used in the construction. The research also illustrates the danger of not properly considering all these factors may result in dissatisfaction of users, and may lead them to alter or modify their houses. This may lead to illegal and possibly unsafe modifications, or at least to unsatisfactory visual appearance. Finally, based on the study of both traditional and contemporary houses, the findings of the empirical study, and the opinions of experts, a set of guidelines for future house designs are presented. The guidelines inform and possibly assist designers, planners, academics and Libyan public policy makers to achieve the goals of providing new housing concepts and forms, which are appropriate to the requirements of residents, and which do not detract nor constrain their social and cultural activities.

The growth of the international movement to involve the public in urban planning urges us to find new ways to achieve this. Recent studies have identified information communication technologies (ICT) as a mechanism to support such movement. It has been postulated that integrating geographic information system (GIS), virtual reality (VR) and Internet technologies will facilitate greater participation in planning activity and therefore strengthen and democratise the process. This is a growing area of research. There is, however, concern that a lack of a theoretical basis for these studies might undermine their success and hamper the widespread adoption of GIS-VR combination (GVIS). This thesis presents a theoretical framework based on the Learning System Theory (LST). ICT technologies are then assessed according to the framework. In the light of the assessmenta, prototype has been designed and developed based on a local urban regeneration project in Salford, UK. The prototype is then evaluated through two phases, namely formative evaluation and summative evaluation, to test the feasibility of the framework. The formative evaluation was focused on evaluating the functionality of the prototype system. In this case, evaluators were experts in IT or urban planning. The summative evaluation focused on testing the value of the prototype for different stakeholder groups of the urban regeneration project from local residents to planning officers. The findings from this research indicated that better visualization could help people in understanding planning issues and communicate their visions to others. The interactivity functions could further support interaction among users and the analysis of information. Moreover, the results indicated that the learning system theory could be used as a framework in looking at how GVIS could be developed in order to support public participation in urban planning.

Governments all around the world have tried to address the problem of providing adequate and affordable housing to the nation over the last three decades. With no exemption, the Malaysian Government is committed to provide all Malaysians, particularly those in the low-income categories, access to adequate and affordable housing. Even with the numerous housing programmes implemented over the various five-year Malaysia Plans, there is still a shortage of affordable homes for the low-income people. The shortage of low-cost dwelling units, along with the high cost of limited land has resulted in rapid expansion of squatter settlements in urban areas. Around the World there is a shift from public to private finance for the delivery of infrastructure projects or related services. However, it has not been implemented to the same extent in affordable housing. This investigation examines not just the measurable deviation from the Malaysia Plan targets, but more importantly, determines an explanation for the deviation and develops a new model of public private partnership for affordable housing. The aim of this research is "to develop a housing model for implementation in affordable housing schemes through the promotion of innovative partnerships between the Government and Private Developers in Malaysia". The research methodology was a combination of literature investigation andinductive reasoning in which a theoretical proposition was tested and developed during data collection and analysis. The data collection included literature review, questionnaires, and follow up interviews with private developers in Malaysia. This research study identifies three models for partnerships between the Government and private developers for affordable housing in Malaysia. An evaluation process was undertaken to assess the appropriateness of the proposed models. The three models will provide tangible benefits in the provision of and access to affordable housing.

This thesis is concerned with the improvement of construction practices by studying the application in the sector of some core principles underlying current production management theories. The research is motivated by the recognition in recent literature that the best production practices world-wide have a common core. The core principles investigated in this research are the "reduction of cycle time", "reduction of variability", "increase of transparency" and "build of continuous improvement into the process". The fundamental rationale underlying these principles is the concept of flow where production is seen as composed of waiting, transporting, inspecting and transformation (processing) activities. According to this concept, transformation activities are the only ones that actually add value. Hence, all other activities should be reduced or eliminated from the flow whilst increasing the efficiency of transformation activities. The assessment of construction practices against the theory was carried out through six case studies, based in England and Brazil, and a complementary meta-case. Cross-case study analysis showed that construction already applies all heuristic approaches relating to the flow principles under study. However, the intra-case study analysis revealed a serious lack of integration among the literal replications identified in each of the case studies. Integration of practices matching the theory is critical since the evidence suggests that there is a correlation between production performance and the level of integration among literal replications. An additional case study investigated the issue of how to implement these principles in the practice of construction. The interaction with the host company happened through an Action Learning set supported by the Revans Centre for Action Learning and Research. The experiment showed that a combination of both "push" and "pull" learning seems to be an appropriate approach for introducing the principles in study in the construction sector. Top management positive support during "gestation" period was the most important factor for motivating people to "pull" the learning after the initial 'push' learning exercise.

The client briefing of the proposed building design is usually in the form of drawings and artistic impressions being presented to the client. However, very few clients are able to read a technical drawing and the artist impressions are limited and do not aid the client to visualise all aspects of the proposed building. During the client briefing process the client needs to have the experiential quality described, to be able to fully understand the design of the proposed building. Generally, humans perceive and directly experience architectural space by building qualities like texture, form, colour, light, scale, movement. A full-scale model of the proposed building would fully afford the experimental qualities. In reality it would be impractical and not cost effective. However, VR technology allows the creation of an inclusion of space in user's mind, through a minimum of means, but achieves a maximum impact, and affords all the experiential qualities offered by a physical model. A virtual model with a high degree of detail which can be explored by the designer and his clients will therefore be of significant help. However, to give clients the best possible impression of the proposed design it is important to understand how dimensions of those designed spaces are perceived. Therefore, a study was carried out focusing on fundamental investigations into the perception of basic architectural dimensions in order to assess the potential usefulness of VR technology in architecture and the client briefing process. In two experiments, subjects were required to estimate egocentric and exocentric dimensions in Virtual Environments and Real World Setting (RWS). The influence of stimuli orientation was also investigated. In estimating all dimensions a magnitude estimation procedure was employed using a modified free-modulus technique. All participants were pre-tested. Psychometric and visual tests were used for choosing an experimental group with a fair degree of homogenity. Two independent subject groups were used. In addition to dimension estimations recall of simple layout and feeling of space were investigated when evaluating the virtual interface. The general null hypothesis assumed that people perceive space in VE as well as in the real world. It has been shown that the results are statistically significant and therefore one was able to reject the general hypothesis. Overall participants underestimated the dimensions in both experiments by approximately 20%. Results and limitations of the study are discussed. The results of the experiments would indicate that VR technology can be used for simulations of architectural spaces because despite underestimations of dimensions it still performed relatively well if one compares it with results of experiments in the Real World Settings.

Station buildings are the most significant components of metro systems that combine underground facilities to the outer world, and include public life in itself. Thus, it is the main objective of that research, to put forward an acknowledgement documentation, which identifies the main design and construction problems of existing and under construction metro station buildings&trade / entrances, and which comes up with solutions to these problems. In the scope of thesis, foremost, basic terminology about station buildings are given and historical development of these buildings in abroad and Turkey are explained briefly. Then, observed problems of metro station entrances are put forward in detail. These problems are mainly categorized as design, construction, material and application related problems. Design part is investigated under following sub-titles: Psychological effects, lighting conditions, space requirements, relationship with city, navigation and disabled accessibility of stations. The affect of recent construction techniques and technological developments on design are also explained. Lastly, material choice and application related problems are investigated through such components of station as wall, floor, ceiling and details. All these problems are assessed by making comparisons with examples both from abroad and from Turkey. Finally, it is comprehended that, because of having weak connections to outer world, the entrances of the stations have adequate contributions neither to the station nor to the city. Assessment of building performance is made under the light of predefined problems and proposals are made in order to be used in design studies to get station entrances free from those problems.