| 1. |
- Byström, Alexandra, et al.
(författare)
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Large scale test on a steel column exposed to localized fire
- 2014
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Ingår i: Journal of Structural Fire Engineering. - : Emerald. - 2040-2317 .- 2040-2325. ; 5:2, s. 147-160
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Tidskriftsartikel (refereegranskat)abstract
- A localized fire is a fire which in a compartment is unlikely to reach flash-over and uniform temperature distribution. Designing for localized fires is generally more difficult than for flash-over compartment fires because of the complexity of the problem. There is also a lack of experimental data. We report here on a full scale test series on a steel column exposed to localized fires. The setup is a 6 meters tall hollow circular column, ϕ = 200 mm with a steel thickness of 10 mm. The unloaded column was hanging centrally above different pool fires. Temperatures of gas and steel were measured by thermocouples, and adiabatic surface temperatures at the steel surface were measured by plate thermometers of various designs. The results are compared with estimates based on Eurocode 1991-1-2 which in all cases studied overestimate the thermal impact for this setup. The input from plate thermometers was used to compute the steel temperatures using finite element methods. Excellent agreement was found if the radiation exchange within the column due to asymmetry of the exposure was taken into account.
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| 2. |
- Iqbal, Naveed, et al.
(författare)
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Numerical Study of Steel Beams in Sub-frame Assembly Validation of Existing Hand Calculation Procedures
- 2015
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Ingår i: Journal of Structural Fire Engineering. - : Emerald. - 2040-2317 .- 2040-2325. ; 6:2, s. 123-140
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Tidskriftsartikel (refereegranskat)abstract
- The design methods currently proposed by the codes prescribe the strength assessment of structures to be based on their strength limit state. These design methods can be applied to isolated steel members to determine their design strengthin fire. The real response of a structural member is, however, more complex due to the thermal expansion and the presence of restraints against this expansion by the surrounding structure. It is therefore imperative to study the response of a structural member at high temperature in a way which includes its interaction with its surroundings. This paper focus on the numerical investigation of steel beams in structural frames connected to concrete filled tubular (CFT) columns through reverse channel connections and comparison to hand calculation procedures. Finite element models (FEM) of the sub-frames were validated against fire tests conducted on sub-frames and then their results were compared to the proposed simplified hand calculation procedures (HCM).
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| 3. |
- Charlier, Marion, et al.
(författare)
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Travelling fire experiments in steel-framed structure : numerical investigations with CFD and FEM
- 2021
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Ingår i: Journal of Structural Fire Engineering. - : Emerald Group Holdings Ltd.. - 2040-2317 .- 2040-2325. ; 12:3
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: The purpose of this paper is to propose a simplified representation of the fire load in computational fluid dynamics (CFD) to represent the effect of large-scale travelling fire and to highlight the relevance of such an approach whilst coupling the CFD results with finite element method (FEM) to evaluate related steel temperatures, comparing the numerical outcomes with experimental measurements. Design/methodology/approach: This paper presents the setup of the CFD simulations (FDS software), its corresponding assumptions and the calibration via two natural fire tests whilst focusing on gas temperatures and on steel temperatures measured on a central column. For the latter, two methods are presented: one based on EN 1993-1-2 and another linking CFD and FEM (SAFIR® software). Findings: This paper suggests that such an approach can allow for an acceptable representation of the travelling fire both in terms of fire spread and steel temperatures. The inevitable limitations inherent to the simplifications made during the CFD simulations are also discussed. Regarding steel temperatures, the two methods lead to quite similar results, but with the ones obtained via CFD–FEM coupling are closer to those measured. Originality/value: This work has revealed that the proposed simplified representation of the fire load appears to be appropriate to evaluate the temperature of steel structural elements within reasonable limits on computational time, making it potentially desirable for practical applications. This paper also presents the first comparisons of FDS–SAFIR® coupling with experimental results, highlighting promising outcomes.
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| 4. |
- Nadjai, Ali, et al.
(författare)
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Travelling fire in full scale experimental building subjected to open ventilation conditions
- 2023
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Ingår i: Journal of Structural Fire Engineering. - : Emerald Group Holdings Ltd.. - 2040-2317 .- 2040-2325. ; 14:2, s. 149-166
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: In the frame of the European RFCS TRAFIR project, three large compartment fire tests involving steel structure were conducted by Ulster University, aiming at understanding in which conditions a travelling fire develops, as well as how it behaves and impacts the surrounding structure. Design/methodology/approach: During the experimental programme, the path and geometry of the travelling fire was studied and temperatures, heat fluxes and spread rates were measured. Influence of the travelling fire on the structural elements was also monitored during the travelling fire tests. Findings: This paper provides details related to the influence of travelling fires on a central structural steel column. Originality/value: The experimental data are presented in terms of the gas temperatures recorded in the test compartment near the column, as well as the temperatures recorded in the steel column at different levels. Because of the large data, only fire test one results are discussed in this paper.
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| 5. |
- Possidente, L., et al.
(författare)
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Fire buckling curves for torsionally sensitive steel members subjected to axial compression
- 2022
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Ingår i: Journal of Structural Fire Engineering. - : Emerald. - 2040-2317 .- 2040-2325. ; 13:2, s. 171-193
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: Buckling should be carefully considered in steel assemblies with members subjected to compressive stresses, such as bracing systems and truss structures, in which angles and built-up steel sections are widely employed. These type of steel members are affected by torsional and flexural-torsional buckling, but the European (EN 1993-1-2) and the American (AISC 360-16) design norms do not explicitly treat these phenomena in fire situation. In this work, improved buckling curves based on the EN 1993-1-2 were extended by exploiting a previous work of the authors. Moreover, new buckling curves of AISC 360-16 were proposed. Design/methodology/approach: The buckling curves provided in the norms and the proposed ones were compared with the results of numerical investigation. Compressed angles, tee and cruciform steel members at elevated temperature were studied. More than 41,000 GMNIA analyses were performed on profiles with different lengths with sections of class 1 to 3, and they were subjected to five uniform temperature distributions (400–800 C) and with three steel grades (S235, S275, S355). Findings: It was observed that the actual buckling curves provide unconservative or overconservative predictions for various range of slenderness of practical interest. The proposed curves allow for safer and more accurate predictions, as confirmed by statistical investigation. Originality/value: This paper provides new design buckling curves for torsional and flexural-torsional buckling at elevated temperature since there is a lack of studies in the field and the design standards do not appropriately consider these phenomena.
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| 6. |
- Sandström, Joakim, Teknisk licentiat, 1979-
(författare)
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Life safety in single-story steel frame buildings, Part I - deterministic design
- 2019
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Ingår i: Journal of Structural Fire Engineering. - : Emerald Group Publishing Limited. - 2040-2317 .- 2040-2325. ; 10:4, s. 435-445
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Tidskriftsartikel (refereegranskat)abstract
- This paper discusses fire safety design of single story-, single compartment buildings and evaluates whether time to structural damage is a relevant criterion when lethal fire conditions develop long before any structural fire damage can occur. Current performance-based design practice aims at achieving the life safety objective by preventing structural failure for the entire duration of a natural fire or for a fixed time of standard fire exposure. Prevention of structural fire damage is always relevant for multistory buildings, or buildings with complex geometries as structural fire damage may then threaten occupants and/or firefighters outside the area directly affected by the fire. However, for single-story-, single-compartment buildings, prevention of structural fire damage is less relevant in relation to the life safety objective.The advantage of the new design philosophy presented in this paper is the possibility to define how the level of structural fire resistance in single-story-, single-compartment buildings can be determined in a consistent way. This level of fire resistance requirement in these buildings differ amongst countries but could be harmonized by accepting of the design philosophy suggested in this paper.The proposed approach is demonstrated in a design case study of a steel truss in a typical Swedish single-story steel frame building. While not complying with deemed to satisfy fire resistance ratings, it is argued that the proposed design still can fulfill the life safety objective.
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| 7. |
- Sandström, Joakim, Teknisk licentiat, 1979-
(författare)
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Life safety in single-story steel frame buildings, Part II - probabilistic design
- 2020
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Ingår i: Journal of Structural Fire Engineering. - : Emerald Group Publishing Limited. - 2040-2317 .- 2040-2325. ; 11:3, s. 379-394
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Tidskriftsartikel (refereegranskat)abstract
- PurposeThis paper aims to investigate the probability of unacceptable consequences from structural fire damage in a typical Scandinavian single-story steel frame building and discusses it in relation to life safety. This paper is a complement to the paper “Life safety in single-story steel frame buildings, Part I – deterministic design” by Sandström (2019) which considers the same design philosophy but with a probabilistic design approach.Design/methodology/approachThe reliability of a single-story steel frame building is investigated by using crude Monte Carlo simulation by including consideration to the fire conditions.FindingsThe investigated building does not meet the safety levels as stipulated by EN 1990 for structural fire damage. However, by including consideration to the fire conditions in the compartment, it is shown that the life safety objective is not compromised by the structural fire damage, i.e. the structure remains intact as long as any individuals/firefighters can survive within the fire area compartment.Originality/valueThis paper presents practical application of a conceptual paper presenting a general approach to structural fire safety design and the life safety objective.
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| 8. |
- Schmid, Joachim, et al.
(författare)
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Timber under real fire conditions - the influence of oxygen content and gas velocity on the charring behavior
- 2018
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Ingår i: Journal of Structural Fire Engineering. - : Emerald Group Publishing Limited. - 2040-2317 .- 2040-2325. - 9781605953205 ; 9:3, s. 222-236
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Tidskriftsartikel (refereegranskat)abstract
- Purpose – The purpose of this study is to investigate the influencing factors on the charring behaviour of timber, the char layer and the charring depth in non-standard fires. Design/methodology/approach – This paper summarizes outcomes of tests, investigating the influences on the charring behavior of timber by varying the oxygen content and the gas velocity in the compartment. Results show that charring is depending on the fire compartment temperature, but results show further that at higher oxygen flow, char contraction was observed affecting the protective function of the char layer. Findings – In particular, in the cooling phase, char contraction should be considered which may have a significant impact on performance-based design using non-standard temperature fire curves where the complete fire history including the cooling phase has to be taken into account. Originality/value – Up to now, some research on non-standard fire exposed timber member has been performed, mainly based on standard fire resistance tests where boundary conditions as gas flow and oxygen content especially in the decay phase are not measured or documented. The approach presented in this paper is the first documented fire tests with timber documenting the data required.
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| 9. |
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