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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.
1

BUCKLING AND POST-BUCKLING RESPOSNE OF SINGLE CURVATUE BEAM-COLUMNS UNDER THERMAL (FIRE) LOADS

SOLTANI, GHULAM H 01 May 2017 (has links)
The main objective of this research was to study the buckling and post-buckling response of axially restrained beam-columns under thermal loading. Also the effects of slenderness ratios on pre-buckling and post-buckling behavior which is neglected in AISC specification was examined. The results of this study indicate that: a) Both the deflection and end moment amplification factors are significantly smaller for the restrained beam-columns subjected to temperature increase than the corresponding unrestrained beam-columns subjected to (mechanical) axial loads. b) The deflection amplification factors tend to decrease with decreasing ratio of end moments. However, reverse seems to occur for the moment amplification factors and as the moment amplification factors tend to increase with decreasing moment ratio particularly in the pre-buckling and the initial post-buckling range (0.1 < T/Tcr < 1.5). c) The thermal amplification factors tend to be smaller than the AISC values even in the pre-buckling range with those for the slender beam-columns significantly smaller than those for the shorter beam-columns.
2

Brandbelastning i träbyggnader : Jämförande beräkning och kartläggning om hur branschen hanterar permanet brandbelastning

Eriksson, Kajsa, Jenny, Löfgren January 2020 (has links)
Wood is a renewable material, it is strong in relation to its weight, climate smart but also combustible. Owing to its many advantages and the easy access in Sweden, wood is motivated as a topical building material. However, the aspects related to the combustible nature need to be considered in the design of buildings with a wooden frame. Whether and in such cases how to take into account the increased permanent fire load is a problem of which there are shared opinions. Today's regulatory framework is unclear in some aspects in its formulation and thus leaves room for interpretation. The purpose of this work is to investigate the reasonableness of tabulated data for permanent fire load and the sharp boundary between a BR1 building and a BR0 building but also by surveying how the industry handles the issue. In order to assess the reasonableness for the tabulated data, the method has been calculations with two different methods; one that follows BBR's guidelines (method 1) and another where calculations of the charring depth (method 2) have been performed, as well as a survey and a literature study. The result from the calculations in method 1 shows that in order for the level of the total fire load not to exceed the standard value for a residence of 800 MJ/m2, a low coefficient is required, and thus in principle all wood is assumed to be protected. According to the calculations in method two, it is possible to read out how the permanent fire load is affected by different protective linings and carbonation rates. The survey shows that the most common way to dimension fire protection is through simplified sizing, which entails that one does not have to consider whether the permanent fire load increases due to a combustible frame. There are divided opinions about whether Boverket's rules are enough to achieve adequate protection and how to handle it. The literature study shows that for the timber frame to be counted as fully protected it needs to be three layers of fire gypsum board in the ceiling and that two layers on the walls. Several conclusions can be drawn; the calculations indicate that a permanent fire load of 200 MJ/m2 (2013:11) is unreasonable in a wooden frame building also that if the permanent fire load is considered it becomes costly both economically and in terms of space. Even that Boverket's rules need to be clarified and adapted further against tall wood buildings and that fire projectors work differently and the experience of working with tall wood buildings differs greatly.
3

Effect Of Vehicles&#039 / Blockage On Heat Release Rate In Case Of Tunnel Fire

Kayili, Serkan 01 December 2009 (has links) (PDF)
Road and railways tunnels are constructed for decreasing the transportation time inside city or intercity. The fire safety systems are mounted for the safe use of tunnels. Therefore, it is important to accurately predict the fire-induced air velocity,temperature and smoke concentrations in tunnel fires in order to design efficient fire protection systems. To this end, scaled tunnel models are used and experiments are carried to understand the phenomena on these tunnel models. In addition, the studies for investigating the tunnel fire phenomena and their methods of modeling techniques for fire experiments are mentioned. In the literature, there is no sufficient information about vehicles&#039 / blockage effect on heat release rate and temperature distribution inside tunnel with different ventilation velocities. As a result, in order to research this subject, the scaled model tunnel is constructed in Fluid Mechanics Laboratory. Based on the Froude number scaling, wood sticks with different configuration inside the model tunnel are burned in a controlled environment. The heat release rate measurement, sampling of gases after combustion, mass loss rate of burning models and temperature distribution along the tunnels with different longitudinal ventilation velocities are measured to investigate the effect of different cross-sectional areas of the burning substances. Furthermore, the model vehicles having a square base area are built according to wood crib theory. The results are investigated with statistical techniques called &quot / Analysis of Variance&quot / and general results have been tried to be reached. It is determined that the variation of air velocity inside tunnel is not so effective, but model vehicle&#039 / s cross sectional area is directly proportional to heat release rate.
4

Brandrisker i däckhotell : Är samhällets krav på byggnadstekniskt brandskydd tillräckligt?

Öhrling, Emil January 2021 (has links)
Syftet med studien är att undersöka de risker som finns i samband med brand i däckhotell, samt utvärdera om samhällets krav på byggnadstekniskt brandskydd är tillräckligt för att hantera risknivån. Samhällets krav i studien är Boverkets byggregler BFS 2011:6 med ändring till och med BFS 2020:4 (BBR) och den kravställning som sker i enlighet med förenklad dimensionering. Kraven i BBR har kvantifierats för att möjliggöra en jämförelse mellan BBR och de verkliga förutsättningar som återfinns på däckhotell. Studien behandlar enbart tre av de fem punkter som BBR baseras på. Utveckling och spridning av brand och rök inom byggnadsverket ska begränsas, spridning av brand till närliggande byggnadsverk ska begränsas och hänsyn ska tas till räddningsmanskapets säkerhet vid brand. Det finns erfarenheter kring bränder i däcklager men ingen samlad bild av hur däckhotell bör hanteras i regelverken, eller om det är förenligt med byggreglernas intention och räddningstjänstens praktiska erfarenheter att utföra insats. Hur ska då brandskyddet utformas i däckhotell för att samhällets krav ska vara uppfyllt? I ett däcklager kan det handla om flera tusen däck som lagras samtidigt. Metodval för att besvara frågeställningarna var att utifrån verkliga däckhotell tillsammans med forskning och studier inom området, genomföra en rad olika analyser. Detta för att kunna besvara frågorna kvantitativt och/eller kvalitativt. Alla frågeställningar krävde dock flera antaganden för att vara möjliga att besvara. För att erhålla något att basera antagandena mot, genomfördes en fallstudie på verkliga däckhotell. Därefter skapades fem olika geometriska modeller baserade på de verkliga byggnaderna av volym, konstruktionsmaterial och ventilationsmöjligheter. Fallstudien visade även på stor variation på antalet däck som fanns placerade i däckhotell. Dock kan det konstateras att brandbelastningen i ett däckhotell överskrider 1600 MJ/m2 golvarea. Det konstruktionsmaterial byggnaden är uppförd med har stor inverkan på temperaturen i brandrummet. Däckhotell uppförda med en betongkonstruktion ger bättre förutsättningar för de brandavskiljande komponenterna att upprätthålla den brandbegränsande funktionen, detta i jämförelse med ett däckhotell uppfört av plåt med isoleringskärna. En brandcellsgräns som utsätts för den temperaturutveckling som sker i byggnad med väggar och tak av plåt-/isoleringskonstruktion, kommer eventuellt inte att begränsa brandspridningen under avsedd tid. De två skyddsbarriärerna som anges i BBR för att begränsa brandspridning mellan byggnader är skyddsavstånd eller att ytterväggen utformas som en brandcellsgräns, men där funktionen av en brandcellsgräns blir beroende av byggnadens konstruktionsmaterial. Fungerande skyddsavstånd är under förutsättning att öppningarna i fasad är begränsade och inte är större än en normal garageport. Syftet med att skydda närliggande byggnader uppfylls därmed inte. Skyddsavståndet bör vara i relation till arean på möjliga öppningar istället för ett fast värde. Ska skyddsavståndet vara fast bör det ske reglering av arean på möjliga öppningar och begränsa storleken eller kritisk strålningsnivå som får uppkomma på närliggande byggnad. Granskning av räddningsmanskapets säkerhet var en jämförelse mellan BBR och intervjuer på hur en räddningsinsats skulle kunna genomföras. Det som diskuterades var vilka risker branden och byggnaden utgör, samt hur dessa kan påverka genomförandet av insatsen. Brandtekniska åtgärder för att ta hänsyn till räddningsmanskapets säkerhet vid insats finns inte i erforderlig omfattning, vid brandteknisk projektering enligt förenklad dimensionering. Utan tidig detektion är risken överhängande att branden är för omfattande för att användning av invändiga brandposter för begränsning ska kunna vara möjlig. Dock är den enskilt viktigaste åtgärden för räddningsmanskapets säkerhet är att säkerställa tillgången till rätt mängd släckvatten vid byggnaden. Däckhotell placerade i containers är den enda byggnadsgeometri vilken kan projekteras enligt förenklad dimensionering. Den lagringsmetoden ger bäst möjlighet till en lyckad räddningsinsats och låg riskbild, och de är den enda modellen där brandcellsgränser helt klart skulle uppfylla sitt syfte både i klass EI 30 och EI 60. Containers har normalt inga fönster eller andra likvärdiga öppningar. / The aim of the thesis is mainly to investigate the risks that exist in case of fire in tire hotels and to evaluate whether society's requirements for fire protection in buildings are enough to manage this level of risk. Society's requirements in the study are Boverket's building regulations, BFS 2011:6 with amendments up to BFS 2020:4, (BBR) and the requirements that takes place in accordance with simplified design. The requirements in BBR have been quantified to enable a comparison between BBR and the actual conditions found in tire hotels. The study only treats three of the five items which BBR is based on. Development and spread of fire and smoke within the construction works is limited, spread of fire to adjacent construction works is limited and consideration has been taken to the rescue team's safety in case of fire. It exists some experience of fires in tire storage, but not a general picture of how a tire hotel should be design according to the building regulations, nor if it´s compatible with the building regulations' intention or the rescue team's practical experience of carrying out a rescue operation. The question is how the fire protection should be designed in tire hotels so that society's requirements can be fulfilled? When it can be thousands of tires which are stored at the same time in a tire hotel. The method to answer the questions was to carry out a few different analyses based on real tire hotels, together with research and studies in this area, so the questions could be answered quantitatively and/or qualitatively. However, all questions required some assumptions to be answered. To obtain something to base the assumptions against, a case study on real tire hotels was conducted. Five different geometric models were therefore created based on the buildings in terms of volume, construction materials and ventilation openings. The case study also showed a great variation in the number of tires that were stored in the hotels. Even with the variation, it can be stated that the fire load in a tire hotel exceeds 1600 MJ/m2 per floor area. The buildings construction material has a big impact on the fire temperature in the room. Tire hotels with a concrete construction provide better conditions for the fire-separation components to maintain the limiting function, in comparison with a construction of metal sheets with a core of insulation. A fire compartment boundary that is exposed to a temperature rise that occur in a metal structure, may not have the function over time it supposed to limit the spread of fire to other rooms during the intended time. BBR specifies two protective barriers to limit the spread of fire to adjacent construction, which are safety distances or that an exterior wall is designed as a fire compartment boundary. The function to limited fire spread by a fire compartment boundary is dependent on the building's construction material to fulfill its purpose. For a safety distance to work, the openings in the facade must be limited and not larger than a normal garage door. The purpose of protecting adjacent construction is therefore not fulfilled. The safety distance should be in relation to the area of ​​ openings instead of a fixed value. If the safety distance is a fixed value, the areas of openings should be regulated, if not, the size of the critical radiation that occur on an adjacent construction should be limited. Examination of the rescue team's safety was a comparison between BBR and interviews on how a rescue operation could be carried out. Under the interviews it was discussed what type of risks that are caused by the fire and the building, and how these risks can affect the implementation of the operation. The fire technical arrangements do not fulfill its purpose, to create the level of safety that are required for the rescue team when the fire technical design is according to a simplified design. Without early detection, the risk is imminent that the fire is too large for a person to use an indoor fire hydrant. The most important arrangements for the safety of the rescue team are however to ensure access to the right volume of water near the building. Tire hotels placed in containers are the only type of building which can be projected according to simplified design. This storage method provides the best opportunity for a successful rescue operation with a low risk.  Containers are also the only geometric model where fire compartment boundary would clearly fulfill its purpose, in both class EI 30 and EI 60. Containers have normally no windows or other equivalent openings.
5

Modelo para otimização ao atendimento a ocorrências de incêndios: estudo de caso para a cidade de São Carlos - SP / Model for optimizing the service to fire occurrences: case study for the city of São Carlos - SP

Bizerra, Rafael Cavalcanti 04 August 2014 (has links)
O crescimento da população urbana requer o aumento dos serviços prestados pelos gestores públicos em consonância com as interações espaciais vividas pelo homem, tornando a administração do espaço urbano uma tarefa árdua e complexa. A inexistência ou a falha na prestação de serviços básicos relacionados com a segurança pública aumenta potencialmente os riscos de sinistros para a população. O objetivo desse trabalho é avaliar a distribuição espacial dos agentes e neutralizantes de incêndio na cidade de São Carlos-SP. Para essa finalidade estudou-se o posicionamento dos agentes e neutralizantes e suas relações no espaço, através de análises realizadas com o uso de um SIG, as quais indicaram a existência de problemas relacionados com a quantidade e a distribuição dos neutralizantes nessa cidade. Utilizando as ferramentas disponíveis no QGIS, foi possível desenvolver e propor uma solução estrutural para melhorar a alocação dos equipamentos de segurança e propor uma solução não estrutural por meio de tecnologia embarcada que proporcionou um menor tempo de deslocamento para abastecer as viaturas em casos de ocorrências de incêndios. Os cenários avaliados mostraram que é possível obter níveis de cobertura de toda a malha urbana, apenas com a realocação de parte dos equipamentos já instalados e com a instalação de alguns poucos hidrantes na rede. / The urban population growth requires increased services provided by public managers in harmony with the spatial interactions experienced by man, making the management of urban space an arduous and complex task. The absence or failure in providing basic services related to public security increases a lot the risk of accidents for the population. The aim of this study is to evaluate the spatial distribution of fire agents and neutralizers fire in the city of São Carlos-SP. For this purpose it was studied the positioning of the fire agents and neutralizers and their relations in space through analyzes with the use of a GIS, that indicated the existence of problems related to the amount and distribution of neutralizers in this city. Applying the tools available in QGIS, was possible to develop and propose a structural solution to improve the allocation of security devices and propose a non-structural solution using embedded technology that allowed shorter shift to water supply the vehicles in cases of occurrences of fires. The evaluated cases showed that it is possible to obtain coverage levels across the urban area, only reallocating the already installed equipment and the installation of a few more hydrants in the network.
6

Modelo para otimização ao atendimento a ocorrências de incêndios: estudo de caso para a cidade de São Carlos - SP / Model for optimizing the service to fire occurrences: case study for the city of São Carlos - SP

Rafael Cavalcanti Bizerra 04 August 2014 (has links)
O crescimento da população urbana requer o aumento dos serviços prestados pelos gestores públicos em consonância com as interações espaciais vividas pelo homem, tornando a administração do espaço urbano uma tarefa árdua e complexa. A inexistência ou a falha na prestação de serviços básicos relacionados com a segurança pública aumenta potencialmente os riscos de sinistros para a população. O objetivo desse trabalho é avaliar a distribuição espacial dos agentes e neutralizantes de incêndio na cidade de São Carlos-SP. Para essa finalidade estudou-se o posicionamento dos agentes e neutralizantes e suas relações no espaço, através de análises realizadas com o uso de um SIG, as quais indicaram a existência de problemas relacionados com a quantidade e a distribuição dos neutralizantes nessa cidade. Utilizando as ferramentas disponíveis no QGIS, foi possível desenvolver e propor uma solução estrutural para melhorar a alocação dos equipamentos de segurança e propor uma solução não estrutural por meio de tecnologia embarcada que proporcionou um menor tempo de deslocamento para abastecer as viaturas em casos de ocorrências de incêndios. Os cenários avaliados mostraram que é possível obter níveis de cobertura de toda a malha urbana, apenas com a realocação de parte dos equipamentos já instalados e com a instalação de alguns poucos hidrantes na rede. / The urban population growth requires increased services provided by public managers in harmony with the spatial interactions experienced by man, making the management of urban space an arduous and complex task. The absence or failure in providing basic services related to public security increases a lot the risk of accidents for the population. The aim of this study is to evaluate the spatial distribution of fire agents and neutralizers fire in the city of São Carlos-SP. For this purpose it was studied the positioning of the fire agents and neutralizers and their relations in space through analyzes with the use of a GIS, that indicated the existence of problems related to the amount and distribution of neutralizers in this city. Applying the tools available in QGIS, was possible to develop and propose a structural solution to improve the allocation of security devices and propose a non-structural solution using embedded technology that allowed shorter shift to water supply the vehicles in cases of occurrences of fires. The evaluated cases showed that it is possible to obtain coverage levels across the urban area, only reallocating the already installed equipment and the installation of a few more hydrants in the network.
7

Structures in underground facilities : Analysis of a Concrete Column’s Capacity to Withstand Extraordinary Fire Loads / Konstruktioner i undermarksanläggningar : Analys av en betongpelares förmåga att motstå extraordinär belastning vid brand

Andersson, Anna, Carlson, Eva-Sara January 2012 (has links)
The report present a Master of Science in engineering work carried out at Mälardalen’s University, made this work within the research project METRO. The work is a part of the research project METRO. The focus of the METRO project is on the protection of underground rail mass transport systems e.g. tunnels and subways stations. The aim with this work was to determine if a concrete column placed close to the tracks at a subway station can withstand the effect and temperature of a fire in a burning train comparable to the effects and temperatures that showed at the full scale test carried out within the METRO project. A literature review was made previous to the following case study. The results from this show that the column is negligible affected by the fire. / METRO project 2009-2012
8

Stahlbetonplatten verstärkt mit Textilbeton unter Brandbelastung

Ehlig, Daniel, Jesse, Frank, Curbach, Manfred 03 June 2009 (has links) (PDF)
Im Rahmen experimenteller Untersuchungen wurden Stahlbetonplatten hergestellt, mit verschiedenen textilen Bewehrungen verstärkt, mit 125 % Gebrauchslast vorgeschädigt und anschließend unter Gebrauchslast mit einer Brandbelastung nach der Einheitstemperaturkurve (ISO-834, Cellulosic curve) beaufschlagt. Alle Platten hielten der Brandbelastung bei gleichzeitiger Biegebeanspruchung mehr als 60 Minuten stand und zeigten weder Betonabplatzungen noch andere optische Schädigungen auf. Die für dieses überraschend positive Ergebnis verantwortlichen Mechanismen werden diskutiert, sind aber noch nicht vollständig verstanden. Eine Schlüsselrolle spielt dabei vermutlich das gute Rissverhalten von Textilbeton und interne Umlagerungen zwischen Textil und Stahlbewehrung.
9

A gestão de riscos como alternativa de prevenção de incêndio em arquivos públicos : estudo de caso

Antunes, Marco Antônio das Graças January 2011 (has links)
Submitted by Maurílio Figueiredo (maurilioafigueiredo@yahoo.com.br) on 2013-02-22T19:51:45Z No. of bitstreams: 1 DISSERTAÇÃO_GestãoRiscoAlternativa.pdf: 41214411 bytes, checksum: 7caa77944d2a0c8f76333d07df2ca056 (MD5) / Approved for entry into archive by Neide Nativa (neide@sisbin.ufop.br) on 2013-02-25T14:13:29Z (GMT) No. of bitstreams: 1 DISSERTAÇÃO_GestãoRiscoAlternativa.pdf: 41214411 bytes, checksum: 7caa77944d2a0c8f76333d07df2ca056 (MD5) / Made available in DSpace on 2013-02-25T14:13:29Z (GMT). No. of bitstreams: 1 DISSERTAÇÃO_GestãoRiscoAlternativa.pdf: 41214411 bytes, checksum: 7caa77944d2a0c8f76333d07df2ca056 (MD5) Previous issue date: 2011 / ABSTRACT: The buildings of public archives shelter documents of permanent value, which are of inalienable and imprescriptible guard. To check the level of fire protection to these permanent records in each building surveyed, it was applied the global analysis of fire risk using the Gretener Method. The text of the “IT 35-CBMMG”, based on this method of performance (widely known) provides fire protection alternatives for the historical buildings (and their contents) of Minas Gerais State, Brazil, when it is not possible or aesthetically desirable, the adoption of security normative or prescriptive measures. The research result showed that showed that the buildings where are installed the public archives are of no conformity to risk of fire due to an in the safety versus protection. Another quick observation was the high volume of documents on paper (main fire load) accommodated in rooms of insufficient area to contain them, incurring specific fire loads much higher than the stipulated level in the specific standard. With the successive employment of active and passive protection measures in these constructions, the safety factors after each trial immediately improved, giving the building and its occupants a pro-safety situation, compared to the outbreak of fire, until unfavorable. / As edificações sede de arquivos públicos custodiam documentos de valor permanente, sendo estes inalienáveis e de guarda imprescritível. Para verificação do nível de proteção contra incêndio a esses documentos permanentes, em cada uma das edificações pesquisadas, foi aplicada a análise global de risco de incêndio, decorrente do Método de Gretener. O texto da IT 35 do CBMMG, baseado nesse método de desempenho (mundialmente conhecido) fornece alternativas de proteção contra incêndio às edificações (e ao seu conteúdo) que compõem o patrimônio histórico mineiro, quando não seja possível ou esteticamente conveniente, a adoção de medidas de segurança de ordem normativa ou prescritiva. O resultado da pesquisa mostrou que as edificações onde estão instalados os arquivos públicos estão em situação de insegurança frente ao risco de incêndio, em razão de um desequilíbrio na relação segurança versus proteção. Outra rápida constatação foi o elevado volume de documentos no suporte papel (principal carga de incêndio) acomodados em espaço de superfície insuficiente para comportá-los, incorrendo cargas de incêndio específicas muito superiores ao valor estipulado em norma. Com o emprego sucessivo de medidas de proteção passiva e ativa nessas edificações, os coeficientes de segurança melhoraram imediatamente a cada ensaio, conferindo ao prédio e aos seus ocupantes uma situação pró-segurança, frente ao risco de incêndio, até então desfavorável. Edificações que abrigam instituições arquivísticas, necessitam de um de sistema de segurança contra incêndio e pânico que monitore diuturnamente as áreas de interesse, com rápida detecção de um foco de fogo e acionamento de alarme, seguido de imediato e eficiente combate por brigadistas treinados, no mínimo. ______________________________________________________________________________________________________
10

Brandskydd i byggnader med exponerad stomme av KL-trä : En kartläggning av olika brandtekniska lösningar för flerbostadshus

Öberg, Andreas, Lejdström, Fredrik January 2021 (has links)
Purpose: The purpose with this work has been to investigate and map selected fireprotection methods in a number of projects. The possibilities and limitations with exposedCLT have been investigated. Method: The method consists of a literature study, interviewstudy, construction site visit and survey. The literature study has been carried out with theaim of presenting relevant facts to the subject and creating a basis for the interview study.The interviews were conducted with fire consultants for the work´s investigated projects.Two of the projects also included construction site visit, of which one of the projects belongsto the partner of this work, Peab. During the visits of the construction sites a tour of thebuilding were carried out and shown where the exposed CLT was placed. The results from theinterviews and construction sites visits are the basis for the survey. Results: The resultsshow that analytical dimension of the fire protection is required when constructing multistory residence with internally exposed CLT. Limitations with exposed CLT are due, amongother things, to the fact that untreated wood does not fulfils the requirements set in BBR forthe surface layer. Delamination contributes to increased fire load as the underlaying slats areexposed to fire. The current study contains two projects carried out with exposed CLT,Notuddsparken and ETC apartment buildings. The projects have dimensioned each withanalytical dimension but with different fire protection methods. Notuddsparken has beenconstructed with automatic sprinkler systems and the ETC apartment buildings have beenconstructed with fire protection impregnation of the exposed CLT. Conclusions:Conclusions established in the work shows that when using exposed CLT analyticaldimension of the fire protection is required. Most of the fire consultants in this work haveexpressed that they do not feel comfortable with dimensioning fire protection for buildingswith exposed CLT, based on the current state of knowledge.

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