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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Development of KM model for knowledge management implementation and application in construction projects

Ahmad, Hesham Saleh Mahmoud January 2011 (has links)
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.
12

Predicting the seismic behavior of the Dywidag ductile connector (DDC) precast concrete system a master's project /

Kenyon, Elizabeth M. McDaniel, Cole C. January 1900 (has links)
Thesis (M.S.)--California Polytechnic State University, 2008. / Mode of access: Internet. Title from PDF title page; viewed on January 29, 2009. Major professor: Cole McDaniel, Ph.D., P.E. "Presented to the faculty of California Polytechnic State University, San Luis Obispo, California." "In partial fulfillment of the requirements for the degree [of] Master of Science in Architecture with a Specialization in Architectural Engineering." "July 2008." Includes bibliographical references (p. 78-81). Also available on microfiche.
13

The structural behaviour of timber joints made with fully overlapping nails

Porteous, Alexander January 2003 (has links)
An integrated programme of experimental and analytical work was carried out to evaluate the nonlinear semi-rigid characteristics of timber connections using fully overlapping nails subjected to short duration lateral loading and moment. The investigation is part of a continuing programme of research at Napier University into the behaviour of timberjoints using fully overlapping nails as the connecting Z -1 mechanism. The effects of the factors and material properties that influence the behaviour of nailed joints were addressed in a structured and controlled way allowing semi-empirical models to be developed for the lateral load behaviour of rnulti-nailed timber joints using steel and plywood gusset plates. A quality control procedure was established for the testing programme and consistent standards were applied to the preparation and testing work. The semi-empirical models that were developed included for the effect of timber density: crussept late material effect- nail strength; number of nails: nail diameter; row spacing and the effect of the moisture content in the timber. They covered joints assembled with and without a gap between the timber and the gusset plates and for joints assembled with steel gusset plates, the effect of the predrill size used in the gusset plate was also investigated. The model results compared very well with the results from tests, accurately predicting the non-linear behaviour of the joints up to failure. An extensive analytical and experimental study was carried out to investigate the moment-rotation behaviour of these types ofjoints. Two linear arýd four non-linear models were developed for each type of joint and the efficiencies of the models were compared to detennine the one that best simulated the joint behaviour. The linear models consistently underestimated the capacity of the joint, giving conservative results. The best solutions were obtained by applying the torsion formula used for steel connections and incorporating the nail behaviour models developed for the non-linear lateral load joints. Account was taken of the non-linear behaviour of the connection and alternative models using fixed and moveable centres of rotation were developed. Very good comparisons were achieved between these models and the test results. A detailed comparison was made between the behaviour of the joints using the lateral load displacement models and Eurocode 5 (EC5) and it was concluded that EC5 rules did not accurately simulate the behaviour of this type of joint. It was concluded that the nail spacing rules in the code did not apply to fully overlapping nails. A limit state design method based on the principles used in EC5 has been developed from the models for the design of joints using fully overlapping nails and subjected to lateral loading or moment. The semi-rigid behaviour of the joints was also investigated and it was concluded that to safely predict the response of structures assembled with fully, overlapping nails. the semi-rigid behaviour must be included for in the analysis procedure. Rigidity factors, end fixing moment reduction factors and the secant rotational stiffness coefficients for the joints were derived. It was also shown that where the analysis was limited to the serviceability limit state. a modified elastic method of analysis could be used and where it was beyond this state a non-linear method of analysis was required.
14

Performance measurement and mathematical modelling of integrated solar water heaters

Garnier, Celine January 2009 (has links)
In a period of rapidly growing deployment of sustainable energy sources the exploitation of solar energy systems is imperative. Colder climates like those experienced in Scotland show a good potential in addressing the thermal energy requirement of buildings; particularly for hot water derived from solar energy. The result of many years of global research on solar water heating systems has outlined the promising approach of integrated collector storage solar water heaters (ICS-SWH) in cold climates. This calls for a need to estimate the potential of ICS-SWH for the Scottish climate. This research project aims to study and analyse the performance of a newly developed ICS-SWH for Scottish weather conditions, optimise its performance, model its laboratory and field performance together with its environmental impacts and analyse its integration into buildings and benefits of such a heating system, for the primary purpose of proposing a feasible ICS-SWH prototype. Laboratory and field experiments were performed to investigate the performance of the newly developed ICS-SWH and the parameters affecting it which were fundamental to modelling its performance. This was followed by developing a thermal macro-model able to compare the temperature variation in different ICS-SWH designs; including internal temperature and external weather conditions for a given aspect ratio and to evaluate the performance of this ICS-SWH for laboratory and field conditions. This was followed by a three-dimensional Computational Fluid Dynamic (CFD) analysis of the ICS-SWH in order to optimise the fin spacing as a means of improving its performance. A Life Cycle Assessment (LCA) and monetary analysis considering the whole life energy of the different ICS-SWH designs were carried out using a previously developed thermal model in order to establish the most viable ICS-SWH with the smallest carbon footprint. Finally, a study to show how the ICS-SWH could be integrated into buildings and its potential benefits to builders and households was undertaken. Through this work, important parameters for modelling laboratory and field performance of ICS-SWH are established. The innovative modelling tool developed can predict the bulk water temperature of the ICS-SWH for any orientation and location in the world with good accuracy. Improvements of the ICS-SWH fin design were suggested through the CFD analysis while keeping the costs to a minimum. The ICS-SWH prototype showed a high commercial potential due to its environmental and monetary benefits as well as its potential for integration into commonly used solar water heating installations and modern methods of construction such as roof panels which could result in a viable commercialisation of the prototype.
15

Life cycle assessment of aluminium-clad timber windows

Asif, Muhammad January 2002 (has links)
Over the last century a temperature rise of 0.6 C m global climate and the affiliated greenhouse effects have inflicted enormous impacts in the form of natural catastrophes, economical losses, health problems and seasonal disorder. If human activities continue at existing pace, a further temperature rise of 2.5 C is being anticipated over the next hundred years, which may cause unimaginable damage to humanity and ecology of the planet. In such a prevailing global environmental scenario sustainability is the need of hour and should be given the prime importance in execution of activities in all sectors in order to keep future secure for coming generations. Windows are amongst the most sensitive elements in a building envelope, also, due to their multi-disciplinary role, they are important not only for their effects on interior environment but also for the energy performance of the building. Energy contents and environmental impacts of the materials involved, add up on to window significance in the ecology of buildings. Energy efficient windows with least possible environmental burden over their whole life cycle are thus very important in achieving desired levels of sustainability in general, particularly in buildings. The present work addresses the sustainability of double glazed aluminium clad timber windows adopting the life cycle assessment (LCA) approach. LCA of windows helps cutting down the associated ecological burdens at all stages, i.e. extraction/production of materials, operation, maintenance and disposal of windows at the end of their service life. Cost effectiveness and productivity, the important features of sustainability, have been evaluated for aluminium clad timber and timber windows on the basis of life cycle cost assessment (LCCA) approach. Value engineering (VE) of aluminium clad timber windows has also been addressed. Running and/or maintenance costs which largely determine the life cycle costing have been estimated and the most cost effective options are presented. Four different types of windows, made of aluminium, aluminium clad timber, PVC and timber frame, have also been compared with respect to the ecology of frame materials - covering energy contents and environmental loads, maintenance and durability, service life and costing. A survey has been carried out with the help of housing authorities, architects and surveyors within UK, to study the performance of these windows in real life. A series of accelerated tests have been carried out to study the weathering performance of the candidate windows. The results have revealed that aluminium clad timber windows have excellent resistance against weathering conditions and they perform better than aluminium, PVC and timber windows under any conditions. In an ongoing research project at Napier, copper (Cu) coated silicon carbide (SiC) reinforcement particles have been used in aluminium 6061 matrix to enhance the mechanical properties of the Al SiC metal matrix composite (MMC), which is a prospective material to be used in window hardware. Results have indicated that Cu coating does not bring any additional corrosion loads onto the MMC. Recommendations for further work have also been laid out.
16

Increasing effectiveness of public private partnerships in the Irish construction industry

Gunnigan, L. January 2007 (has links)
By 2003 the first Irish Public Private Partnership (PPP) projects had reached the operational stage. Media reports were emerging of significant differences in the effectiveness of these projects. This research set out to find a means by which effectiveness of PPPs could be increased and to develop a model that would assist PPP practitioners with this task in the future. Through a literature review, the Irish PPP process was mapped, the changes encountered in the introduction of PPP were investigated and a conceptual model – based on a traditional process model - was proposed. The model was tested by examining the outcomes of two projects and assessing the effect of participant attitudes on these outcomes. The projects were analysed in terms of Risk, Value and Innovation, and three propositions were offered: • there were differences in project outcomes; • there were differences in the attitudes of the project participants; • the attitudes influenced the outcomes. Using a combination of research methods, the data were gathered and analysed. The first two propositions were proven for Risk and Value but not for Innovation. In addressing the third proposition, a pattern matching exercise was undertaken and a number of findings were reached. These findings were further tested to establish their validity, credibility and reliability. The results showed that specific elements of participant attitudes were found to affect some of the project outcomes and that these had a significant effect on the overall success of the project. The findings showed that PPP conducted as outlined by the conceptual model would not maximise effectiveness. The model was revised so that it commenced with analysis of the desired outcomes and proceeded by working back through the PPP process to define the inputs necessary for success. Using this information, the model was refined, making it ready for use by future PPP practitioners.
17

The assessment of corrosion-damaged concrete structures

Webster, Michael Peter January 2000 (has links)
Data from existing research are linked together to produce an overview of the effects of chloride-induced corrosion on reinforced concrete structures. The effects of chloride-induced corrosion on the following mechanisms have been investigated: (i) Cracking. (ii) Bond strength. (iii) Flexural strength. (iv) Shear strength. (v) Column behaviour. Models have been developed to link material and structural aspects of deterioration. Despite the complexity of the behaviour, many of the models are modifications to existing procedures contained in UK codes. Material and structural models are integrated together in a spreadsheet for assessing the variation in load-carrying capacity with time. Time to cracking and residual load-carrying capacity are found to be sensitive to small variations in key parameters such as the cover and the surface chloride level. Predictions from a spreadsheet model indicate that structures designed and built to BS 8110 should achieve their design life without the need for significant repair. The predictions also indicate that the UK Highways Agency was justified in making BD 57 more onerous than BS 5400. With validation against further test data the procedures developed in this Thesis could form the basis for codes of practice for the assessment of corrosion-damaged concrete structures and the durability design of new concrete structures.
18

Evacuation modelling of mixed-ability populations in fire emergencies

Rubadiri, Lindiwe January 1994 (has links)
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.
19

Comparison study of traditional and contemporary housing design with reference to Tripoli, Libya

Amer, A. A. January 2007 (has links)
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.
20

Designing a geographic visual information system (GVIS) to support participation in urban planning

Zhang, X. January 2004 (has links)
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.

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