The reliability based design of composite beams for the fire limit state

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dc.contributor.advisor Dunaiski, P. E.
dc.contributor.advisor Retief, J. V.
dc.contributor.author Van der Klashorst, Etienne en_ZA
dc.contributor.other University of Stellenbosch. Faculty of Engineering. Dept. of Civil Engineering.
dc.date.accessioned 2007-12-03T12:56:39Z en_ZA
dc.date.accessioned 2010-06-01T08:43:58Z
dc.date.available 2007-12-03T12:56:39Z en_ZA
dc.date.available 2010-06-01T08:43:58Z
dc.date.issued 2007-03
dc.identifier.uri http://hdl.handle.net/10019.1/2236
dc.description Thesis (MEng (Civil Engineering))--University of Stellenbosch, 2007.
dc.description.abstract In the past use was made of prescriptive design rules to provide for the fire limit state. Modern Design Codes provide the scope and the means to design for fire in a performance based manner. The Eurocode provides guidance on the actions on structures exposed to fire as well as methods to predict the structural behaviour of elements in fire. Structural designers can now incorporate the use of parametric fire curves to describe compartment fires. These fire models are not an extension of the old nominal standard temperature time curves. Parametric curves are analytical models that are based on natural fire behaviour. The temperature in the fire compartment can be predicted in a scientific manner taking account of fire loads, ventilation conditions and compartment characteristics. The combination of rational fire models and temperature dependant structural behaviour enables designers to predict whether elements will fail during a fire. This is an improvement on the empirical prescriptive fire resistance ratings, used to date. Multi-storey steel framed structures, with composite floors, were identified as structures with high inherent fire resistance and robust behaviour. The composite beams in the floor structure were identified as critical elements when subjected to fire. The deterministic design and the reliability level of these elements were studied. Deterministic fire design procedures are presented that can be used to design unprotected composite beams for the fire limit state. The reliability of the deterministic design procedures was evaluated through a First Order Reliability Method. Parametric fire curves are suitable for reliability analysis due to the fact that they can be described by stochastic variables. The fire load was determined to be the dominant variable influencing the reliability level of the composite beams. The ventilation conditions of the fire compartment also has important implications for the temperature development of the composite beams. The reliability analyses results show that reasonably sized composite beams can be used as unprotected elements in smaller fire compartments with moderate fire loads. It was found that a structural element’s total probability of failure can be improved by the use of active fire fighting measures. The benefit of active fire fighting measures can be quantified by considering their probability of failure. By use of conservative assumptions and basic knowledge of fire engineering principles, rational design methods can provide safe and economical solutions for fire design of composite beams. en_ZA
dc.format.extent 1868821 bytes en_ZA
dc.format.mimetype application/pdf en_ZA
dc.language.iso en_ZA en_ZA
dc.publisher Stellenbosch: University of Stellenbosch
dc.subject Theses -- Civil engineering en_ZA
dc.subject Dissertations -- Civil engineering en_ZA
dc.subject.lcsh Composite construction en_ZA
dc.subject.lcsh Building, Fireproof en_ZA
dc.subject.lcsh Fire protection engineering en_ZA
dc.subject.other Civil engineering en_ZA
dc.title The reliability based design of composite beams for the fire limit state en_ZA
dc.type Thesis en_ZA
dc.rights.holder University of Stellenbosch


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