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Fire Performance of Connections in Laminated Veneer LumberChuo, Terence Chung Biau January 2007 (has links)
The embedment strength of timber with respect to exposure temperature has not been widely studied. Some studies have suggested that the timber totally loses its embedment strength when the timber temperature reaches 300℃. This research concentrates on the embedment strength study of Laminated Veneer Lumber (LVL) timber product exposed to elevated temperatures up to 250℃ using singly bolted connections. Experiments showed that the embedment strength of LVL decreased at a constant rate from 0.08 kN/mm² to 0.025 kN/mm² once the bolt temperature increased from ambient conditions. The embedment strength was then assumed to remain at strength of 0.025 kN/mm² as the bolt temperature continues to increase from 120℃. The difference between the estimated failure load based on Johansen's Equations and the experimental failure load for the connections tested under fire conditions was less than 30%. The estimation was based on bolt strength reduction using NZS 3404, the experimental charring rate and the experimental embedment strength. The predicted failure mode agreed with experimental for all types of connection.
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Computer simulation of hollowcore concrete flooring systems exposed to fireChang, Jeremy John January 2007 (has links)
Multi-storey buildings with precast hollowcore concrete floor systems are very common in New Zealand and in many other countries, but the structural behaviour of such systems under fire exposure is not easy to predict because of the complex geometry, composite construction, and a wide range of possible support conditions. The 2006 version of the New Zealand Concrete Standard NZS3101 introduces new details for connection of hollowcore floor units to reinforced concrete supporting beams to improve seismic performance, but the fire performance of the new connection systems is unknown. Currently available methods for simulating fire performance of hollowcore slabs are not suitable for design purposes. Therefore, a simple yet sufficiently accurate simulation method needs to be developed. This study was carried out using a proposed simulation method to investigate the fire performance of hollowcore floor slabs with different connection details between the hollowcore units and their reinforced concrete supporting beams conforming to NZS3101. The proposed simulation method is examined on the platform of SAFIR, a non-linear finite element program that includes both thermal and structural analysis. The proposed simulation method was validated using available experimental results from a limited number of tests. It does not take account of shear and anchorage failures or spalling effects, so designers should consult other studies for this behaviour of hollowcore concrete flooring systems. By using the proposed simulation scheme in SAFIR, it is investigated whether the tensile membrane action established through beams parallel to the hollowcore units and different floor aspect ratios will enhance the fire resistance of hollowcore concrete flooring systems. From the simulation results it is concluded that rigid connections at both the ends and the sides of the hollowcore flooring systems to the supporting beams provide better fire resistance than rotationally flexible connections, and the fire resistance of hollowcore flooring systems can be increased by using stiffer supporting beams at the end of the slabs and also by decreasing the spacing between the beams parallel to the hollowcore units.
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Analysis of Fire Performance, Smoke Development and Combustion Gases from Flame Retarded Rigid Polyurethane FoamsAdeosun, David January 2014 (has links)
Rigid polyurethane foam is a polymeric material which is widely used for thermal insulation in building construction and other applications. Given recent emphasis on energy conservation and efficiency, there has been continuous growth in its use over the years. This raises significant fire safety concerns since polyurethanes are inherently very flammable and prone to release toxic gases as the foam thermally decomposes and burns. To improve fire safety characteristics by reducing ignitability and flammability of the foams, various flame retardants (FR) have been introduced into base foam formulations. But with the introduction of FR agents, there has been rising concern within the fire safety community and general public regarding the overall benefits versus detrimental impacts of even commonly used FR agents. In the case of rigid polyurethane foam, however, such an assessment is difficult as there are few cross comparisons in the literature that detail the impacts of different concentrations of common fire retardants, such as brominated, phosphorus-based and expandable graphite agents, on the fire behavior, smoke development and toxic gas production for even single base foam formulations.
The present experimental work focuses on a systematic evaluation of these factors using three common, commercial fire retardants added in concentrations of 0%wt, 10%wt and 20%wt to a single formulation of rigid polyurethane foam. Cone calorimeter and smoke density tests are used to simulate well ventilated and poorly ventilated fire conditions during material fire performance assessment, while FTIR, Novatech P 695 gas analyzers and TD-GC/MS methods are used to investigate the gases evolved during oxidative pyrolysis and combustion of the samples. Concentration measurements of principal fire gases such as CO, CO2, reduced O2, and NOx
are combined with more detailed investigation of the volatile organic compounds generated during the fire testing. Use of gas absorption sampling followed by off-line Thermal Desorption/Gas Chromatography/Mass Spectrometry (TD-GC-MS) analysis for identification of toxic gases has proven of significant benefit in this application. The full set of data obtained provides a more comprehensive identification of the evolved products during three characteristic periods in the combustion process. As such, it expands current knowledge and provides valuable new insight and understanding of thermal degradation, combustion and smoke development, as well as overall fire performance, of fire retarded rigid polyurethane foams in well-ventilated and poorly ventilated environments.
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Fire and structural performance of non-metallic timber connectionsBrandon, Daniel January 2015 (has links)
Recent studies showed the need for timber connections with high fire performance. Connections of members in timber structures commonly comprise steel connectors, such as dowels, screws, nails and toothed plates. However, multiple studies have shown that the presence of exposed metal in timber connections leads to a poor performance under fire conditions. Replacing metallic fasteners with non-metallic fasteners potentially enhances the fire performance of timber connections. Previous studies showed that Glass Fibre Reinforced Polymer (GFRP) dowels can be a viable replacement for steel dowels and that Densified Veneer Wood functions well as a flitch plate material. However, as the resin matrix of GFRP dowels is viscoelastic, connection creep, which is not studied before, can be of concern. Also no research has been carried out on the fire performance of these connections. Therefore, a study of the creep behaviour and the fire performance of non-metallic timber connections comprising GFRP dowels and a Densified Veneer Wood flitch plate was performed, as is discussed in this thesis. Predictive models were proposed to determine the connection slip and load bearing capacity at ambient and elevated temperatures and in a fire. The material properties and heat transfer properties required for these models were determined experimentally and predictions of these models were experimentally validated. Furthermore, an adjustment of the predictive model of connection slip at ambient temperature allowed approximating the creep of the connection. The material properties, required for the creep model, were determined experimentally and predictions of the model were compared to results of longterm connection tests. The study confirmed that timber members jointed with non-metallic connectors have a significantly improved fire performance to timber joints using metallic connections. Models developed and proposed to predict fire performance gave accurate predictions of time to failure. It was concluded that non-metallic connections showed more creep per load per connector, than metallic connections. However, the ratio between initial deflection and creep (relative creep) and the ratio between load level and creep were shown to be similar for metallic and non-metallic connections.
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A Study into the Behavior of Reinforced-Concrete Columns under Fire Exposures using a Spreadsheet-Based Numerical ModelEmberley, Richard Lawrence 24 April 2013 (has links)
Fire is a significant threat to the structural integrity of buildings. Depending on the architecture of the structure and the intensity and duration of the fire event, structural members may lose strength and stiffness eventually leading to collapse whether by flexural buckling or crushing. The focus of this research is on the behavior and fire performance of reinforced-concrete columns under fire conditions. In order to effectively study column performance with differing loading, aggregate and dimensional characteristics under varying time-temperature curves and fire exposures, a numerical model was constructed in Microsoft Excel. The spreadsheet model allowed for complete transparency of the calculations and provided a means to visualize the data in flexible ways. ANSYS and several published column furnace tests were used to benchmark the heat transfer and structural analysis portions of the model. One, three and four-sided fire exposures along with the ASTM E119 fire curve and a natural fire curve were used to study latent heating effects, increasing and decreasing eccentricities, moment magnification, and failure modes. Assessments of column structural capacity were performed in accordance with the provisions of ACI 318. The completed model served as an effective tool for the thesis and is available to help aid students and engineers investigate the design of reinforced concrete columns under fire conditions through integration the heat transfer analyses and the structural evaluations.
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Behavior of Wood Exposed to Fire: A Review and Expert Judgement Procedure for Predicting Assembly Failure.Bland, Kenneth Edward 10 February 2005 (has links)
This paper summarizes research on the structural perfomance of wood elements and assemblies exposed to fire and reviews methodologies available to predict performance. This reasecrh provides a wealth of information on topics such as how fast a flame spreads across the surface of wood, how much smoke is produced during combustion and at what rate does wood char and at what heat release rate.
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A Methodology for Global Comparison of Fire Testing Standards in Transportation ApplicationsPrine, Brenda January 2013 (has links)
In recent decades, many manufacturing industries have globalized their operations and the Canadian manufacturing sector has experienced dramatic downsizing. For a manufacturing company to succeed therefore, it is necessary for them to operate with a global perspective. In the area of fire safety, this requires understanding of, and compliance with, global regulatory requirements.
This research develops a systematic approach that can be utilized to analyze and compare the complex fire safety regulatory requirements that are stipulated for a selected topic in various countries. The approach developed is sufficiently general that it can be leveraged to compare and contrast global standards in any field or discipline. The methodology outlines six aspects of the regulatory environment that must be considered in sorting standards and then uses spreadsheets and a mind mapping program to elucidate the many relationships that exist amongst the current standards.
In this work, flammability test requirements for public transportation seating are studied, with a major emphasis on seating for railway applications. Requirements for seating in aviation, automotive (both cars and buses) and military vehicles are included in the discussion for comparative purposes.
Fire is a complex phenomenon that is difficult to characterize. The legislated testing protocols reflect this complexity with some geographic jurisdictions mandating as many as six different types of fire testing for rail seating. This work looks in depth at two of the main types of fire testing: flame spread testing and toxic effluent testing.
Flame spread testing was chosen because it is widely required, and toxic effluent testing was chosen because of the many complexities and ambiguities present amongst these standards. Eleven flame-spread tests are compared on a semi-quantitative basis, and eight fire effluent toxicity tests are discussed on a qualitative basis.
The technique developed was useful to elucidate the relationships, similarities and differences amongst the fire safety requirements for transportation seating. There are large differences in requirements among transportation sectors as well as on a geographical basis. Using this technique, it was possible to categorize the flame spread tests into two groups and to compare the relative intensity of the tests within each of these subsets. The fire effluent toxicity tests varied so much in approach that only qualitative comparisons were possible.
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A Methodology for Global Comparison of Fire Testing Standards in Transportation ApplicationsPrine, Brenda January 2013 (has links)
In recent decades, many manufacturing industries have globalized their operations and the Canadian manufacturing sector has experienced dramatic downsizing. For a manufacturing company to succeed therefore, it is necessary for them to operate with a global perspective. In the area of fire safety, this requires understanding of, and compliance with, global regulatory requirements.
This research develops a systematic approach that can be utilized to analyze and compare the complex fire safety regulatory requirements that are stipulated for a selected topic in various countries. The approach developed is sufficiently general that it can be leveraged to compare and contrast global standards in any field or discipline. The methodology outlines six aspects of the regulatory environment that must be considered in sorting standards and then uses spreadsheets and a mind mapping program to elucidate the many relationships that exist amongst the current standards.
In this work, flammability test requirements for public transportation seating are studied, with a major emphasis on seating for railway applications. Requirements for seating in aviation, automotive (both cars and buses) and military vehicles are included in the discussion for comparative purposes.
Fire is a complex phenomenon that is difficult to characterize. The legislated testing protocols reflect this complexity with some geographic jurisdictions mandating as many as six different types of fire testing for rail seating. This work looks in depth at two of the main types of fire testing: flame spread testing and toxic effluent testing.
Flame spread testing was chosen because it is widely required, and toxic effluent testing was chosen because of the many complexities and ambiguities present amongst these standards. Eleven flame-spread tests are compared on a semi-quantitative basis, and eight fire effluent toxicity tests are discussed on a qualitative basis.
The technique developed was useful to elucidate the relationships, similarities and differences amongst the fire safety requirements for transportation seating. There are large differences in requirements among transportation sectors as well as on a geographical basis. Using this technique, it was possible to categorize the flame spread tests into two groups and to compare the relative intensity of the tests within each of these subsets. The fire effluent toxicity tests varied so much in approach that only qualitative comparisons were possible.
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Multivalence, liminality, and the theological imagination : contextualising the image of fire for contemporary Christian practiceDyer, Rebekah Mary January 2018 (has links)
This thesis contends that the image of fire is a multivalent and theologically valuable image for application in British Christian communities. My research offers an original contribution by contextualising the image of fire for Christian practice in Britain, and combining critical observation of several contemporary fire rites with theological analysis. In addition, I conduct original case studies of three Scottish fire rituals: the Stonehaven Fireball Ceremony, the Beltane Fire Festival, and Up-Helly-Aa in Lerwick, Shetland. The potential contribution of fire imagery to Christian practice has been overlooked by modern theological scholarship, social anthropologists, and Christian practitioners. Since the multivalence of the image has not been fully recognised, fire imagery has often been reduced to a binary of ‘positive' and ‘negative' associations. Through my study of non-faith fire rituals and existing Christian fire practices, I explore the interplay between multivalence, multiplicity, and liminality in fire imagery. I demonstrate that deeper theological engagement with the image of fire can enhance participation, transformation, and reflection in transitional ritual experience. I argue that engaging with the multivalence of the image of fire could allow faith communities to move beyond dominant interpretive frameworks and apply the image within their own specific context. First, I orientate the discussion by examining the multivalence of biblical fire imagery and establishing the character of fire within the British social imagination. Second, I use critical observation of community fire practices in non-faith contexts to build a new contextual framework for the analysis of fire imagery. Finally, I apply my findings to a contextual analysis of existing Christian fire practices in Britain. Throughout, I argue that sensory and imaginative interaction with the image of fire provides a way to communicate and interact with theological ideas; experience personal and communal change; and mediate experience of the sacred.
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