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Disaster Prevention and Management: An International Journal, vol. 12 no. 4
Type: Research Article
ISSN: 0965-3562

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Book part

Jean L. Dyer

Each of the four objectives can be applied within the military training environment. Military training often requires that soldiers achieve specific levels of performance…

Abstract

Each of the four objectives can be applied within the military training environment. Military training often requires that soldiers achieve specific levels of performance or proficiency in each phase of training. For example, training courses impose entrance and graduation criteria, and awards are given for excellence in military performance. Frequently, training devices, training media, and training evaluators or observers also directly support the need to diagnose performance strengths and weaknesses. Training measures may be used as indices of performance, and to indicate the need for additional or remedial training.

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The Science and Simulation of Human Performance
Type: Book
ISBN: 978-1-84950-296-2

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Article

Ramla Karim Qureshi, Negar Elhami-Khorasani and Thomas Gernay

This paper aims to investigate the need for active boundary conditions during fire testing of structural elements, review existing studies on hybrid fire testing (HFT), a…

Abstract

Purpose

This paper aims to investigate the need for active boundary conditions during fire testing of structural elements, review existing studies on hybrid fire testing (HFT), a technique that would ensure updating of boundary conditions during a fire test, and propose a compensation scheme to mitigate instabilities in the hybrid testing procedure.

Design/methodology/approach

The paper focuses on structural steel columns and starts with a detailed literature review of steel column fire tests in the past few decades with varying axial and rotational end restraints. The review is followed with new results from comparative numerical analyses of structural steel columns with various end constraints. HFT is then discussed as a potential solution to be adapted for fire testing of structural elements. Challenges in contemporary HFT procedures are discussed, and application of stiffness updating approaches is demonstrated.

Findings

The reviewed studies indicate that axial and rotational restraints at the boundaries considerably influence the fire response of steel columns. Equivalent static spring technique for simulating effect of surrounding frame on an isolated column behavior does not depict accurate buckling and post-buckling response. Additionally, numerical models that simulate fire performance of a column situated in a full-frame do follow the trends observed in actual test results up until failure occurs, but these simulations do not necessarily capture post-failure performance accurately. HFT can be used to capture proper boundary conditions during testing of isolated elements, as well as correct failure modes. However, existing studies showed cases with instabilities during HFT. This paper demonstrates that a different stiffness updates calculated from the force-displacement response history of test specimen at elevated temperature can be used to resolve stability issues.

Originality/value

The paper has two contributions: it suggests that the provision of active boundary conditions is needed in structural fire testing, as equivalent static spring does not necessarily capture the effect of surrounding frame on an isolated element during a fire test, and it shows that force-displacement response history of test specimen during HFT can be used in the form of a stiffness update to ensure test stability.

Details

Journal of Structural Fire Engineering, vol. 10 no. 4
Type: Research Article
ISSN: 2040-2317

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Article

Venkatesh Kodur, James Stein, Rustin Fike and Mahmood Tabbador

This paper aims to present an evaluation of comparative fire resistance on traditional and engineered wood joists used in the construction of floor systems in residential housing.

Abstract

Purpose

This paper aims to present an evaluation of comparative fire resistance on traditional and engineered wood joists used in the construction of floor systems in residential housing.

Design/methodology/approach

Fire resistance experiments were carried out on four types of wood joists, namely, traditional lumber, engineered I-joist, castellated I-joist and steel/wood hybrid joist, used in traditional and modern residential construction. The test variables included type of wood joist, support conditions and fire protection (insulation).

Findings

Results from these tests indicate that webs of engineered I-joists and castellated I-joists are highly susceptible to fire, and failure generally occurs through the burn-out of the web. In addition, engineered I-joists have much lower fire resistance than traditional solid joist lumber. The application of an intumescent coating on an engineered I-joist significantly enhances its fire resistance and yields a similar level of fire resistance as that of a traditional lumber joist.

Originality/value

The presented fire tests are unique and provide valuable insight (and information) to the behavior and response of four types of wood joists when subjected to gravity loading and fire conditions.

Details

Journal of Structural Fire Engineering, vol. 8 no. 1
Type: Research Article
ISSN: 2040-2317

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Book part

Kurt M. Menning

Forests too thick with fuels that are too continuously spread to resist fire are common throughout the west. After a century or more of actively working to suppress fire

Abstract

Forests too thick with fuels that are too continuously spread to resist fire are common throughout the west. After a century or more of actively working to suppress fire across the landscape, we now recognize that fire is a part of our forests, shrublands, and range, and that it will come whether we wish it or not. At last, managers must realize forests cannot be fire-proofed (DellaSala, Williams, Williams, & Franklin, 2004). We must work with fire rather than against it.

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Living on the Edge
Type: Book
ISBN: 978-1-84950-000-5

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Article

Kamila Cabová, Filip Zeman, Lukáš Blesák, Martin Benýšek and František Wald

This paper aims to present a part of a coupled numerical model for prediction the fire resistance of elements in a horizontal furnace. Temperatures calculated inside the…

Abstract

Purpose

This paper aims to present a part of a coupled numerical model for prediction the fire resistance of elements in a horizontal furnace. Temperatures calculated inside the timber beam are compared to measured values from the fire test.

Design/methodology/approach

The paper presents a part of a coupled numerical model for prediction the fire resistance of elements in a horizontal furnace. The presented part lies in a virtual furnace which simulates temperature environment around tested elements in the furnace. Comparison of results show good agreement in the case when burning of timber is included in the numerical model.

Findings

The virtual furnace presented in this paper allows to calculate temperature environment around three timber beams. After validation of the fire dynamics simulator (FDS) model, the temperature conditions are passed to the FE model which solves heat transfer to the tested element. Temperatures inside the timber beam which are solved in software Atena Science are compared to measured temperatures from the fire test. The comparison of temperatures in three control points shows good accuracy of the calculation in the point closer to the heated edge. An inaccuracy is shown in points located deeper in the beam cross-section – below the char layer.

Research limitations/implications

In conclusion, the virtual furnace has a great potential for investigating the thermal behaviour of fire-resistance tests. A huge advantage inheres in the evaluation of the thermal effect throughout the volume of the furnace, which allows an accurate prediction of fire-resistance tests and evaluation of large number of technical alternatives and boundary conditions. However, passing the temperature field from the FDS model into FE model may decrease the level of accuracy. The solution lies in a coupled CFD-FE model. A weakly coupled model including fluid dynamics, heat transfer and mechanical behaviour is under development at Faculty of Civil Engineering, Czech Technical University in Prague. The fluid dynamics part which is presented in this paper is solved by FDS and the thermo-mechanical part is computed by object-oriented finite element model (OOFEM). The interconnection of both software is made owing to MuPIF python library.

Practical implications

The virtual furnace takes advantage of great possibilities of computational fluid dynamics code FDS. The model is based on an accurate representation of a real fire furnace of fire laboratory PAVUS a.s. located in the Czech Republic. It includes geometry of the real furnace, material properties of the furnace linings, burners, ventilation conditions and tested elements. Gas temperature calculated in the virtual furnace is validated to temperatures measured during a fire test.

Social implications

The virtual furnace has a great potential for investigating the thermal behaviour of fire-resistance tests. A huge advantage inheres in the evaluation of the thermal effect throughout the volume of the furnace, which allows an accurate prediction of fire-resistance tests and evaluation of large number of technical alternatives and boundary conditions.

Originality/value

The virtual furnace has a great potential for investigating the thermal behaviour of fire-resistance tests. A huge advantage inheres in the evaluation of the thermal effect throughout the volume of the furnace, which allows an accurate prediction of fire-resistance tests and evaluation of large number of technical alternatives and boundary conditions. However, passing the temperature field from the FDS model into FE model may decrease the level of accuracy. The solution lies in a coupled CFD-FE model. A weakly coupled model including fluid dynamics, heat transfer and mechanical behaviour is under development at Faculty of Civil Engineering, Czech Technical University in Prague. The fluid dynamics part which is presented in this paper is solved by FDS and the thermo-mechanical part is computed by OOFEM. The interconnection of both software is made thanks to MuPIF python library.

Details

Journal of Structural Fire Engineering, vol. 11 no. 4
Type: Research Article
ISSN: 2040-2317

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Article

Joakim Sandström

This paper aims to investigate the probability of unacceptable consequences from structural fire damage in a typical Scandinavian single-story steel frame building and…

Abstract

Purpose

This 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/approach

The reliability of a single-story steel frame building is investigated by using crude Monte Carlo simulation by including consideration to the fire conditions.

Findings

The 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/value

This paper presents practical application of a conceptual paper presenting a general approach to structural fire safety design and the life safety objective.

Details

Journal of Structural Fire Engineering, vol. 11 no. 3
Type: Research Article
ISSN: 2040-2317

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Article

Andrei Kervalishvili and Ivar Talvik

This paper aims to reliability analysis of axially loaded steel columns at elevated temperatures considering the probabilistic features of fire.

Abstract

Purpose

This paper aims to reliability analysis of axially loaded steel columns at elevated temperatures considering the probabilistic features of fire.

Design/methodology/approach

The response function used in the reliability analysis is based on the non-linear FEM calculations. The stochastic variability of temperature is integrated with the procedure similar to the parameters of loading and material properties. Direct Monte Carlo simulations (MCSs) are implemented for probabilistic analysis. Computational costs are reduced by polynomial approximation of the response function of the column.

Findings

A design method for practical applications in the common Eurocode format is proposed. The proposed method can be used to estimate the failure probability of a steel column in fire conditions. If standard reliability criteria are applied, the results of the steel column buckling capacity in the fire according to the proposed procedure deviate from the Eurocode results in certain parameter ranges.

Originality/value

The proposed method for design calculations makes use of the advantages of MCS results, while the need for the tedious amount of calculations for the end user are avoided as the predefined factors are implemented in the procedure of Eurocode format. The proposed method allows better differentiation of the fire probability in the capacity assessment compared to the existing design methods.

Details

Journal of Structural Fire Engineering, vol. 11 no. 2
Type: Research Article
ISSN: 2040-2317

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Article

Poologanathan Keerthan and Mahen Mahendran

Cold-formed Light gauge Steel Frame (LSF) wall systems are increasingly used in low-rise and multi-storey buildings and hence their fire safety has become important in the…

Abstract

Cold-formed Light gauge Steel Frame (LSF) wall systems are increasingly used in low-rise and multi-storey buildings and hence their fire safety has become important in the design of buildings. A composite LSF wall panel system was developed recently, where a thin insulation was sandwiched between two plasterboards to improve the fire performance of LSF walls. Many experimental and numerical studies have been undertaken to investigate the fire performance of non-load bearing LSF wall under standard conditions. However, only limited research has been undertaken to investigate the fire performance of load bearing LSF walls under standard and realistic design fire conditions. Therefore in this research, finite element thermal models of both the conventional load bearing LSF wall panels with cavity insulation and the innovative LSF composite wall panel were developed to simulate their thermal behaviour under standard and realistic design fire conditions. Suitable thermal properties were proposed for plasterboards and insulations based on laboratory tests and available literature. The developed models were then validated by comparing their results with available fire test results of load bearing LSF wall. This paper presents the details of the developed finite element models of load bearing LSF wall panels and the thermal analysis results. It shows that finite element models can be used to simulate the thermal behaviour of load bearing LSF walls with varying configurations of insulations and plasterboards. Failure times of load bearing LSF walls were also predicted based on the results from finite element thermal analyses. Finite element analysis results show that the use of cavity insulation was detrimental to the fire rating of LSF walls while the use of external insulation offered superior thermal protection to them. Effects of realistic design fire conditions are also presented in this paper.

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Article

Joachim Schmid, Alessandro Santomaso, Daniel Brandon, Ulf Wickström and Andrea Frangi

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.

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.

Details

Journal of Structural Fire Engineering, vol. 9 no. 3
Type: Research Article
ISSN: 2040-2317

Keywords

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