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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.
491

Dimensionering av stålstomme och brandskyddsfärg vid en given brandteknisk klass / Design of steel frame and fire retardant paint with a given classification

Sedin, Johan January 2018 (has links)
WSP Structures in Umeå wants the student to propose a preliminary design for a steel frame with a given input, considering the ultimate limit state and fire. The project has been limited to design the frame for the ultimate limit state and the fire design has been limited to calculate the amount of fire retardant paint needed for fire classification R30 for building components. The frame is delimited to columns, beams, horizontal stabilization and connecting joints between parts. With the help of theory, the resistance and the design amount of fire protection are verified, of which the results are verified.   As a solution, a model is created in the modeling software FEM-Design where load combinations are created by the given input and assumptions. Using the software´s design tool, the needed sections for columns and beams is calculated. Load effects that accords at joints is indicated by the program and is used to design joints and connections between parts according to SBI:s publications for beam-column connections and column footings. Most utilized elements were the “middle column”, which were designed to a HEA 200 profile with an 80% utilization. Detailed results are presented with tables which presents the utilization for each element. Designed columns, beams and joints can be found in level, section and detail drawings.   With the help of the created FEM model and used theory about fire design, the amount of fire retardant paint is calculated with the accidental load combination. The accidental load combination generates a lower utilization, which is used to calculate the needed amount of paint based on the manufacturer´s table. Columns received an amount of 750 g/m2 and beams received an amount of 1000 g/m2. Horizontal stabilizing elements didn´t receive any protection because it could be shown that columns could be calculated with a fixed support during the accidental load combination with a significant lower horizontal load.   The student thesis emphasizes the importance of finding a balance between the amount of paint and section and embracing a discussion about fire protection for joints. The utility rate for columns and beams became a guideline for the utility for joints since the amount of paint applied on the beam and connecting joints is the same, it would be a problem for example if the joint is utilized more than the connected beam. Also, determining the amount of paint needed is difficult if different steel grades are used in a joint and if details such as stiffeners are narrower than the thickness of the connecting column/beam. / WSP byggprojektering i Umeå definierade behov av ett examensarbete vars syfte var att ger ett förslag på en utformning av en stålstomme med ett befintligt indata med hänsyn till brottgränstillstånd och brand. Projektet avgränsades till att dimensionera stommen för brottgränstillstånd och branddimensionering avgränsades till att beräkna hur mycket brandskyddsfärg som behövdes vid brandteknisk klass R30 för byggnadsdelar. Den bärande stommen avgränsades till pelare, balkar, horisontell stabilisering och knutpunkter. Med hjälp av framtagen teori verifierades bärförmågan och dimensionerande mängd brandskyddsfärg. Som lösningsmetod användes dimensioneringsprogrammet FEM-Design där en modell av konstruktionen gjordes och där dimensionerande lastkombinationer genererades utifrån de förutsättningar som gavs. Med hjälp av programmets dimensioneringsverktyg kunde det tvärsnitt som behövdes vid aktuell lasteffekt tas fram för pelare och balkar. I programmet togs lasteffekt som uppträder vid knutpunkter fram, som dimensioneras enligt SBI:s publikationer för ramhörn och pelarfot. Mest nyttjat element blev mittenpelaren vilket blev en HEA 200 profil och fick ett nyttjande på 80 %. Utförligt resultat presenteras i form av tabeller med nyttjandegrad vid dimensionerande lastkombination och med planritning, sektioner och detaljritningar. Med hjälp av nödvändig teori om brand och den gjorda FEM modellen kunde mängden brandskyddsfärg beräknas med olyckslastkombinationer. Olyckslastkombinationer gav upphov till ett lägre nyttjande där färgmängd beräknas utifrån färgtillverkarens tabell. Pelare fick färgmängden 750 g/m2 och balk vid gavel fick färgmängden 1000 g/m2 . Horisontalstabiliserande element målas ej då det var möjligt att påvisa en inspänningseffekt vid pelarfot för olyckslasten. Examensarbetet understryker vikten av att hitta en balans mellan mängden färg och pelardimension och för en diskussion kring brandskyddsfärg vid knutpunkter. Nyttjandegraden för pelare och balkar blev en riktlinje för nyttjandegrad för knutpunkter då mängden färg på balken och anslutande förband är samma. Att bestämma den mängd färg som behövs försvåras om olika stålsorter används i ett förband och ifall detaljer som till exempel avstyvningar är smalare än anslutande pelare/balks godstjocklek.
492

The assessment and applications of a new connector type for use in timber structural systems

Coste, Guillaume January 2010 (has links)
No description available.
493

Economic appraisal and risk analysis of construction automation

Taylor, Mark D. January 2003 (has links)
No description available.
494

Moisture conditions in external timber cladding : field trials and their design implications

Davies, Ivor January 2011 (has links)
This thesis describes the development of technical guidance on timber facade design. The study involved a state-of-the-art review; an exposure trial of external cladding made from Sitka spruce (Picea sitchensis) and the production of construction details and associated information. It was undertaken because timber is an increasingly common cladding material in the UK, being used on low-rise residential buildings and for medium-rise and non-domestic buildings. The risks have, therefore, increased but this is not reflected in published guidance. Sitka spruce was used due to its availability in the UK and its similarity to Norway spruce (P. abies) which is widely used for cladding in Scandinavia. The exposure trial indicated that the moisture content range in timber facades is wider than accepted. The minimum moisture content of around 10% appears to be similar for all types of timber cladding and all species. The maximum appears to vary between species according to their fibre saturation point and is influenced by construction detailing and workmanship. A preliminary model of these interactions is proposed. From a theoretical standpoint, the moisture conditions observed in the trial mean that the (commonly quoted) mean moisture content is all but irrelevant. The mode is a more representative statistic as in most cases the data are skewed towards the fibre saturation point for the species concerned. Most detailing combinations had a moisture content near to the fibre saturation point throughout the winter. Sitka spruce is, therefore, only suitable as external cladding in the UK if preservative treated. Around 40 construction details were produced. They integrate, for the first time, all of the performance requirements applicable to low- and medium-rise timber facades in the UK. The work's key benefit is that the guidance arising from this study rationalises and improves facade design. Further research is, however, needed to validate the moisture content model and extend it to other timber species.
495

Structure-borne sound transmission through resiliently suspended ceilings in timber frame floors

Su, Shenzhi January 2009 (has links)
Resilient bars provide cheap, effective sound insulation. They are increasingly popular in timber floor/ceiling assemblies in the UK following the upgrading of Building Regulations requirements. However, the behaviour mechanisms providing resilient bars with their insulating properties are not well understood. The effects of specific detailed features on their performance are assumed or estimated empirically. Myths relating to property-performance correlation prevail among various product manufacturers. Previous experimental studies revealed either overall effect or only covered the stiffness in the vertical direction. Spring and rod models used elsewhere also failed to predict three-dimensional, asymmetrical facets of resilient bar behaviour. This research investigated the influence of various three-dimensional resilient bar features through examining hypotheses: resilient bars act as springs (either vertical, bending, cantilever or spring hinge), or stiffeners. As these hypotheses are associated with certain material and geometrical features, the results revealed each's influence and relative importance. Three types of test were designed: vibration transmission, apparent stiffness and modal tests. Two representative but distinctly different resilient bar products were chosen as test subjects, which covered the features of interest and involved controversies. Vibration transmission tests were conducted on a series of configurations based on small-scale structures, which could not only demonstrate overall performance but allow detailed parametric investigations. Apparent stiffness tests on small samples enable isolation of spring effects so that their individual contribution could be evaluated. Modal tests revealed how resilient bars modified the vibration modes of the attached plate. By synthesizing the data from the above three angles together with data in the literature, the influence of key features was inferred and evaluated. Mass-spring-mass modelling and statistical energy analysis were carried oout which enhanced understanding of the system's behaviour. The findings led to an optimised resilient bar design and a patentable acoustic hanger system. The latter was prototyped and tested on a floor/ceiling assembly. The results showed that it was more advantageous than current resilient bar systems.
496

Daylighting performance of tubular solar light pipes : measurement, modelling and validation

Zhang, Xiaodong January 2002 (has links)
The innovation of natural daylighting light pipe took place more than twenty years ago. Since then its daylighting performance has been reported in a number of studies. To date, however, no mathematical method that includes the effect of straight-run and bends within light pipes has been made available. Therefore, a generalm athematicalm odel for light pipes is desirablet o assessa nd predict its daylighting performance.F urthermore,s uch a generalm odel can enablet he assessmenot f light pipe system's efficiency and potential in energy saving. A modified form of daylight factor, Daylight Penetration Factor (DPF), has been introduced to build a sophisticated model that takes account of the effect of both internal and external environmental factors, and light pipe configuration. Measurementsa nd mathematicalm odelling activities aimed at predicting the daylighting performance of light pipes with various configurations under all weather conditions in the UK were undertaken. A general daylighting performance model, namely DPF model, for light pipes was developed and validated. The model enables estimation of daylight provision of the light pipes with a high degree of accuracy, i. e. R2 values of 0.95 and 0.97 for regression between predicted and measured illuminance were respectively obtained for the above model. The DPF model uses the most routinely measured radiation data, i. e. the global illuminance as input. Considering that in real applications, light pipes installed in a particular building may not receive the full amount of global illuminance as measured by local meteorological office. This may be due to partial shading of the light pipe top collector dome. Therefore, to enable the application of the DPF model in practical exercisesf undamentalw ork on sky diffuse illuminance measurementsh ave been undertaken. An exhaustive validation has been carried out to examine the DPF model in terms of the structure of the model and its performance. The DPF model was compared against studies by other independent researchersin the field. Independentd ata setsg atheredf rom a separates ite were used to validate the performance of the DPF model. Comprehensive statistical methods have been applied during the course of validation. Relevant, brief economic and environmental impact of the technology under discussion has also been undertaken. One of the main achievementso f this work is the mathematicalm ethod developedt o evaluatet he daylighting performance of light pipes. T'he other main achievement of this work is the development and validation of the DPF models for predicting light pipes' daylighting performance.
497

Properties of hydraulic and non-hydraulic limes for use in construction

Edwards, Andrew J. January 2005 (has links)
The term "lime" comes from the word limestone. Limestone rocks were converted to lime powder by burning (calcining). The process of converting limestone to lime was an old process and it has been well documented, archaeologically. It has been established that the production of lime is the oldest industrial process can"ied out by humankind, dating back thousands of years. In fact, 3650 years ago Moses instructed the people of Israel, after they crossed the Jordan River, to set up large stones and whitewash them with lime and write the laws of God in lime. Lime was the most commonly used cementatious binder until about a century ago, when its use started to decline. It was replaced by Portland cement, a material essentially developed for structural purposes in the era of the industrial revolution. Portland cement has certain advantages over lime. The material develops strength and hardens faster for work to be carried out at a greater pace with better quality control and agreed standards. It has now become the dominant cementitious binder, part of it due to aggressive marketing of the material by the manufacturers. The use of Portland cement in the restoration and conservation of old buildings and structures in the UK over the past few years has resulted in a series of problems and cost millions of Pounds to eradicate. The decline in the use of lime in many countries has not only caused a diminution of its production, but has also contributed to a gradual disappearance of the traditional skills required both to produce a high quality product and to use it in construction. Therefore it is necessary to reintroduce and revive the old tradition of using lime by providing more information about its production and use. At present there are no comprehensive standards or code of practices, British or European to aid engineers and contractors in the use of hydraulic and non hydraulic limes in construction. BS EN 459 (2001) gives guidance on the chemical and physical properties of limes but it does not provide vital information about lime-based mortars e.g. mix proportions, mixing process, bond with masonry units, curing methods and all other necessary aspects to assess in the use of the material in construction. At present it is very easy for engineers, contractors and consultants to misuse lime mortars in new construction or in restoration and conservation of old buildings. Part of the decline in production of lime and reluctance of use in construction is due to the lack of understanding of the material properties and its performance in structures. Therefore it is necessary to examine and revive the old tradition in using lime mortars in construction and look at the new technologies used presently in the production process in order to provide the necessary background and information to aid the use of the material The present study provides a literature review, test results, discussions, conclusions and background information to set up standards in the production and use of hydraulic and non-hydraulic limes and their mortars in the construction of new buildings and the restoration and conservation of old buildings. Hydraulic and non-hydraulic limes have an excellent track record in buildings through history but their use in the UK was missed for some thirty years or more. Part of the reason for undertaking this research programme was to examine the properties of pre-packaged hydraulic limes available in the market at present. The properties of limes vary considerably dependent on the raw materials, composition and manufacturing process. The results of this study showed that there was a great variation in the properties and performance of limes and their mortars. The results also showed that the properties of lime mortar improved by adding different percentages of POliland cement. The research examined the effect of sand grading on the lime mortars compreSSIve, splitting and brick/mortar bond strength. The thesis also investigated the effects of using different casting moulds and curing methods on mortar strength. The results showed that the porosity of lime mortar was one of the reasons it was a success in the past and why it was so important nowadays to use it in the restoration and conservation of historic buildings.
498

Development of multi-criteria decision analysis models for bidding and contractor selection

Abu-Shabeen, Nadine Nabeel January 2008 (has links)
Estimating and bidding a job is one of those essential processes at the heart of a contractor's business. Risk and uncertainty are major considerations in bidding decisions for construction projects. Numerous factors need to be taken into account when making bidding decisions which make them multi-criteria decisions. The present study focuses on developing multi-criteria decision making models to assist in bidding decisions. The Analytical Hierarchy Process (AHP), which is a multi-criteria decision making tool, is used to quantify risk encountered in bidding decisions. The AHP has been employed to model both the bid/no bid and mark-up decisions. The data required for this study was collected from thirty firms operating in Gaza Strip by way of a written structured questionnaire. The data was analysed using the Criterium Decision Plus Software based on the AHP. Ten factors were selected to affect bid/no bid decisions while eleven factors were chosen to influence mark-up decision. Results from the questionnaire survey supported previous studies that profit is not the most important factor in making bid/no bid and mark-up decisions. The results also indicate that the most important factors when making the bid/no bid decision are: the 'need for work' followed by the 'company strength in industry' and 'payment methods'. For the mark-up decision, the 'need for work', 'owner/client and consultant identity' and 'project size' are the most important factors. A real life case study was used to demonstrate the application of the two models. Twelve meetings were conducted with a contractor working in Gaza Strip construction industry in order to gather the required data for the validation. The case study consisted of three different projects, road works, electromechanical and building projects, and the contractor had to make a decision on which projects to bid for and then which of them will result in a higher mark-up. The validity of the two models was confirmed by applying a two-stage Linear Programming (LP) approach to the data obtained from the case study. The results from the LP approach agreed with the outcome from the AHP. The developed AHP models can be easily used by the contractors to assist in making bid/no bid and mark-up decisions. This study investigates the Fuzzy Sets Theory, which is a mathematical approach used to characterise and quantify uncertainty, as a bidding strategy. This study summarises the work that has been done to-date reviewing the fundamental concepts and applications of the Fuzzy Sets Theory in construction. Fuzzy Sets Theory was found to be used widely in construction research but most studies were found theoretical. The research also examines the challenges of using the reverse auction as an open bidding process. In construction industry, reverse auction is one such technique that uses secured Internet technology for tendering process. Advantages of on-line bidding include: the ability to submit more than one bid, time benefits, increasing competitiveness among contractors and attracting unknown bidders. The main drawback of reverse auctions is that the award of the product/service will be based on the price rather than on the quality of the product or service. Furthermore, security and legal issues need further considerations when forming e-contracts for the procurement of construction services. Selecting a suitable contractor to execute a particular project is an important decision for the client to take. Awarding construction contracts based on the price only is not always a successful strategy for contractor selection as it could result in construction delays and cost overruns. In addition to price, factors such as quality and safety need to be taken into account when making the contractor selection decision. In this study, two methods for contractor selection were compared: the points method and the Analytical Hierarchy Process. The two methods were applied to a real life case study for contractor selection. Financial and Quality factors were considered to affect the contractor selection decision. Both methods resulted in selecting the same contractor for executing the project under consderation. The Analytical Hierarchy process provides a flexible and computer based method for contractor selection decision.
499

The evaluation of shear properties of timber beams using torsion test method

Khokhar, Aamir Muhammad January 2011 (has links)
No description available.
500

Modelling the energy resource for buildings and the use of appropriate low carbon technologies

Girard, Aymeric January 2011 (has links)
This thesis investigates the feasibility of the use of Low or Zero Carbon Energy Sources (LZCES) in the built environment and the development of an innovative Integrated Renewable Energy Planner (IREP) tool. It can be divided into four main research areas; an investigation into the on-site renewable energy resource, an analysis in the building energy usage profile, a development of a decision-making tool for the rapid identification of the most appropriate LZCES option and a post occupancy monitoring and modelling of a building. This research work details the following considerations of LZCES: passive solar space heating modelling (PSSH); performance of building integrated including solar water collector (SWH); solar photovoltaic (SPV); wind technology (WT); ground source heat pump (GSHP); tri-generation (TriG); biomass (BioH) and rainwater harvesting (RWH). Recorded Chartered Institute of Building Services Engineer (CIBSE) data from fourteen cities around the UK were used to assess the wind, solar electric, solar passive thermal, solar water thermal, ground source and rain resource. As part of this project, an unoccupied solar house was monitored for one summer and one winter month in East Whitburn, Scotland. A detailed investigation into the effect of external temperature, irradiance and thermal mass was conducted on building perFormance and indoor temperature. It was found that the estimated internal temperature simulation was between 2% to 10% different from the monitored temperature. It could be improved if the thermal mass and ventilation rate were estimated more accurately. A collection of manufacturers' data from 10 WTs, 10 SWHs, 3 SPVs, 2 GSHPs, 2 BioHs, 3 Tries and 2 RWHs was carried out in order to test the performance of the IREP tool. Energy, economy and CO2 saving simulations were done on a number of LZCES systems. A final assessment of the number of different options and their impact on the cost, energy and CO2 saving was performed in order to assess the best combination possible. Future development of the IREP tool may aim to assess more accurately the output of each technologies, develop a more user-friendly facade and integrate more technologies such as light pipes, earth duct, solar wall, concentrated solar power, energy storage, UTES, waste-to-energy plant, fuel cells and to extend potentially to recycled materials. Other weather data from rest of the world could make IREP usable for other project scales and countries.

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