Single storey steel building exposed to fire: An integrated approach for analytical evaluation of steel structures exposed to fire
Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
For some years there has been an ongoing debate in Sweden on how to prove safety of single story buildings made of steel. Due to different interpretations of the rules, at one municipality one building can be considered as it is built according to safety requirements and in another municipality the same building can be treated as the building for which the safety requirements are not fully proven.The main objective of this thesis is to evaluate the fire resistance of a typical industrial hall used as a commercial store in Sweden. This will be done by evaluating a newly built, typical hall-building, which serves as a grocery store. The method used for this is first to assess the hall-building with the use of the temperature reached with the standard fire curve, namely 850 degrees Celsius after 30 minutes. Thereafter evaluate the impact of a fire that has been simulated with Fire Dynamic Simulator (FDS). Four different fire scenarios were analyzed, where the highest temperature reached in the lower chord of the truss was 450 degrees Celsius.To be able to assess the structural resistance of the hall, three trusses in the middle of the building were modelled in the finite element program Abaqus. A temperature field in the middle of the midmost beam is applied and after that the vertical load. The loading was continually increased until a stage where a failure was found. The obtained failure load was compared to the design load of the building. To see whether some modifications of crucial parts could increase the overall structural resistance, a short parametric study was made. The parameters changed were: the thickness of the endplate of the beam, the boundary conditions of the beam and the cross-section area of rods that have been assumed to represent the roof over the three truss beams. In total nine different scenarios were considered.Even though some modifications of the beam, such as alter the boundary condition and thicken the endplate led to an increase of the overall structural resistance, none of the cases evaluated with the temperature of 850 degrees Celsius, could withstand the design load. Stress concentrations so large that plastic deformation occurred in either the supports or the middle of the beam led to failure in all the cases studied. It is rather easy to reach this conclusion, not many steel structures can withstand an elevation of temperature up to 850 degrees Celsius. When using the temperature found in FDS, namely 450 degrees Celsius instead of 850, all the cases studied could withstand the fire.
Place, publisher, year, edition, pages
2012. , 107 p.
Teknik, Finit element metod, Fire dynamics simulator, Bärförmåga, Brand, Brandteknik, Fire saftey design, Stålbyggnad, Single storey building, FDS, FEM, Abaqus, Fire, Steel
IdentifiersURN: urn:nbn:se:ltu:diva-57339Local ID: e069daab-020c-4978-8c41-edd3303ba00eOAI: oai:DiVA.org:ltu-57339DiVA: diva2:1030726
Subject / course
Student thesis, at least 30 credits
Fire Engineering, master's level
Validerat; 20121002 (anonymous)2016-10-042016-10-04Bibliographically approved