This paper presents an experimental-numerical study on the behaviour of High Strength Steel (HSS) columns at elevated temperature, both on Circular Hollow Sections (CHS) and on a Concrete Filled Tube (CFT). The measured yield strength of... more
This paper presents an experimental-numerical study on the behaviour of High Strength Steel (HSS) columns at elevated temperature, both on Circular Hollow Sections (CHS) and on a Concrete Filled Tube (CFT). The measured yield strength of the circular sections was in the order of 820 MPa. In detail, three HSS CHS and a HSS CFT were tested under the standard ISO fire with constant eccentric compression load. The evolution of temperature and defor-mation patterns were measured by means of a comprehensive instrumentation made of ther-mocouples and displacement transducers. Numerical analyses were performed and compared with experimental data by employing stress-strain relationships of carbon steel at elevated temperatures provided by EN1993-1-2 associated with two different sets of reduction factors: i) those provided by EN1993-1-2 valid up to S460 steel grades; and ii) those proposed in the literature and based on tests on HSS.Peer reviewe
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A method has been derived for the fire design of concrete columns in the fire situation. This method has been derived from numerical calculations made with the non linear software SAFIR and has been calibrated to obtain the best fit with... more
A method has been derived for the fire design of concrete columns in the fire situation. This method has been derived from numerical calculations made with the non linear software SAFIR and has been calibrated to obtain the best fit with the results of 76 full scale experimental tests: 16 performed in Belgium (University of Liege and University of Gent), 39 in Germany (Braunschweig) and 21 in Canada (NRC). The model proposed here has been slightly modified in a later version that is now present in Eurocode 2 (EN 1992-1-2), as tabulated data method A (section 5.3.2). This publication is thus a background document of EN 1992-1-2.Peer reviewe
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It is shown that, in some cases, a determination of the ultimate load bearing capacity at a given (requested) fire resistance time is nearly equivalent to the fire resistance time obtained in a transient analysis when the structure is... more
It is shown that, in some cases, a determination of the ultimate load bearing capacity at a given (requested) fire resistance time is nearly equivalent to the fire resistance time obtained in a transient analysis when the structure is submitted to the same load
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Estimation des effets d'un incendie sur la capacité portante de la structure en béto
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Hybrid Fire Testing (HFT) is a technique that allows assessing experimentally the fire performance of a structural element under real boundary conditions that capture the effect of the surrounding structure. To enable HFT, there is a need... more
Hybrid Fire Testing (HFT) is a technique that allows assessing experimentally the fire performance of a structural element under real boundary conditions that capture the effect of the surrounding structure. To enable HFT, there is a need for a method that is unconditionally stable, ensures equilibrium and compatibility at the interface and captures the global behaviour of the analysed structure. A few attempts at conducting HFT have been described in the literature, but it can be shown, based on the analytical study of a simple one degree-of-freedom elastic system, that the considered method was fundamentally unstable in certain configurations which depend on the relative stiffness between the two substructures, but which cannot be easily predicted in advance. In this paper, a new method is introduced to overcome the stability problem and it is shown through analytical developments and applicative examples that the stability of the new method does not depend on the stiffness ratio ...
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... Furumura, F [> >]. Jumppanen, Ula-Maija [VTT > > > >]. Khoury, GA [Imperial college of London > > > >]. Millard, Alain [Commissariat à l'Energie Atomique (Saclay) - CEA > > > >]. Morris,... more
... Furumura, F [> >]. Jumppanen, Ula-Maija [VTT > > > >]. Khoury, GA [Imperial college of London > > > >]. Millard, Alain [Commissariat à l'Energie Atomique (Saclay) - CEA > > > >]. Morris, WA [Building Research Establishment > > > >]. Publication date : Mar-1997. ...
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Fires in large compartments tend to burn locally and to move across the floor over a period of time, this particular behaviour has been discovered to challenge the assumption of uniform gas temperature in the fire compartment. Recent... more
Fires in large compartments tend to burn locally and to move across the floor over a period of time, this particular behaviour has been discovered to challenge the assumption of uniform gas temperature in the fire compartment. Recent studies on fires in large compartments led to the now widely known concept of “travelling fires”. Several models have been proposed so far to describe the evolution in time of travelling fires. Although these models represented an innovative step in the field of travelling fire, major drawbacks of these models can be found in the simplification of fire dynamics (constant spread rate, 1D imposed fire path) and limited field of application (rectangular based geometries). The purpose of this paper is to present a numerical model of travelling fire. The model is based on an improved zone model combined with a cellular automata model. The software GoZone in which the model has been implemented is intended to be a practical solution to analyse fires in large ...
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EACS 2016 Paper No. 132<br><br>This paper describes a novel methodology for conducting stable hybrid fire testing (HTF). During hybrid fire testing, only a part of the structure is tested in a furnace while the reminded... more
EACS 2016 Paper No. 132<br><br>This paper describes a novel methodology for conducting stable hybrid fire testing (HTF). During hybrid fire testing, only a part of the structure is tested in a furnace while the reminded structure is calculated separately, here by means of a predetermined matrix. Equilibrium and compatibility at the interface between the tested "physical substructure" and the "numerical substructure" is maintained throughout the test using a dedicated algorithm. The procedures developed so far are sensitive to the stiffness ratio between the physical and the numerical substructure and therefore they can be applied only in some cases. In fire field, the stiffness of the heated physical substructure may change dramatically and the resulting change in stiffness ratio can lead to instability during the test. To overcome this drawback, a methodology independent of the stiffness ratio has been developed, inspired from the Finite Element Tear...
Abstract. The new steel bridge “Hans-Wilsdorf ” in Geneva is an exceptional steel structure that will drive general traffic through a main transportation axis. As the investment cost of the project is important, a structural fire analysis... more
Abstract. The new steel bridge “Hans-Wilsdorf ” in Geneva is an exceptional steel structure that will drive general traffic through a main transportation axis. As the investment cost of the project is important, a structural fire analysis has been performed to study the sensitivity of the structure to a high temperature exposure, such as a truck in fire on the deck. This analysis will allow deciding whether a severe fire could be an unacceptable economical risk for the bridge. 1
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Fire brigades face a major threat when intervening in a building in fire: the possibility of structural collapse during the cooli ng phase of the fire, or soon thereafter. In the current approaches to structural fire engineering, the fire... more
Fire brigades face a major threat when intervening in a building in fire: the possibility of structural collapse during the cooli ng phase of the fire, or soon thereafter. In the current approaches to structural fire engineering, the fire resistance rating (R) is generally the only measure taken into consideration to characterize the fire performance of structural elements, although t his measure does not reflect the response in real fire conditions. In this work, a s t ndard measure is proposed to characterize the ability of structural members to r esist a natural fire including the decay phases. This measure yields information about the potential occurrence of delayed failure as a function of the duration of th e fire before it started to decrease, whether by self-extinction or due to the action of the fire fighters. The paper presents the method to derive this new standard measure as w ell as results for different typologies of structural elements. Finally, the int erpretation an...
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audience: researcher, professional, studen
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audience: researcher, professional, studen
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Recherches numeriques et experimentales menees a l'Universite de Liege, concernant le beton arme: conclusions sur l'importance des caracteristiques de deformation, a obtenir a partir d'essais transitoires; influence du type de... more
Recherches numeriques et experimentales menees a l'Universite de Liege, concernant le beton arme: conclusions sur l'importance des caracteristiques de deformation, a obtenir a partir d'essais transitoires; influence du type de modelisation, a partir de deux facteurs: branche descendante du diagramme contrainte-deformation du beton et retours elastiques dus aux contraintes thermiques
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This report presents the results of the numerical simulations performed by University of Liege in the framework of work package 6 of the FICEB project financed by the Research Fund for Coal and Steel. A full scale fire test was performed... more
This report presents the results of the numerical simulations performed by University of Liege in the framework of work package 6 of the FICEB project financed by the Research Fund for Coal and Steel. A full scale fire test was performed in Ulster on February 27th 2010 on a composite floor for analysing the behaviour of long cellular steel beams in a complete compartment office in building structure under realistic fire conditions. The aim was to study the possibility of tensile membrane action to develop when the unprotected steel beams in the central part of the floor are made of cellular beams. Predictive numerical simulations of the test have been performed with the software SAFIR in order to define the appropriate structure to be used for the full scale fire test. As predicted, the structure was able to withstand the test without collapse. After the test, the results of the predictive simulations have been compared to the measured results, showing relatively good agreement
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O problema da encurvadura lateral de vigas metálicas sujeitas a altas temperaturas, nomeadamente as que resultam de situações de incêndio, é ainda mal conhecido. O Eurocódigo 3 apresenta na Parte 1-2 um modelo de cálculo simples cuja... more
O problema da encurvadura lateral de vigas metálicas sujeitas a altas temperaturas, nomeadamente as que resultam de situações de incêndio, é ainda mal conhecido. O Eurocódigo 3 apresenta na Parte 1-2 um modelo de cálculo simples cuja validade nunca foi confirmada experimentalmente. Comparam-se os resultados obtidos com a utilização de um programa de elementos finitos para análise não-linear geométrica e material especialmente desenvolvido para o estudo de estruturas sujeitas à acção do fogo, com os resultados obtidos com base naquele Eurocódigo. Foram considerados dois tipos de aço, um perfil 1 da série europeia, um tipo de carregamento e quatro períodos de exposição à curva de incêndio padrão ISO 834. Com base neste estudo numérico foi possível obter uma nova proposta de modelo de cálculo simples; diferente do sugerido no Eurocódigo 3, e que necessita ainda ser validada experimentalmente. Verifica-se que o facto das propriedades mecânicas do aço depender da temperatura e da relação tensão-deformação, a altas temperaturas não ser a mesma que à temperatura ambiente, altera a forma da curva de encurvadura lateral a altas temperaturas
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Future Validate the method on small-scale test setup at ULg fire lab Develop SAFIR® to enable performing HFT Adapt the testing facility for HFT on real size structural elements Advantage of ULg: in-house software SAFIR® + fire lab... more
Future Validate the method on small-scale test setup at ULg fire lab Develop SAFIR® to enable performing HFT Adapt the testing facility for HFT on real size structural elements Advantage of ULg: in-house software SAFIR® + fire lab Hybrid Tests extended to other domains e.g. mechanical eng. Fire tests in laboratory remain crucial to understand the behavior of structures subjected to fire Standard testing • Performed on individual elements • Boundary conditions (loads or supports) kept constant • Most common approach
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This paper deals with the behaviour under fire of vertical walls made of steel sheet piles in retaining walls close to, for example, a traffic road or an industrial facility or in underground structures such as car parks or cut and cover... more
This paper deals with the behaviour under fire of vertical walls made of steel sheet piles in retaining walls close to, for example, a traffic road or an industrial facility or in underground structures such as car parks or cut and cover tunnels. For the later situation, the sheet pile walls support not only the horizontal pressure from the ground but also the vertical loads induced by the different floors. Four experimental tests have been performed in the fire lab of ULiege on a test setup where different soils were located at the back of a heated sheet pile wall, namely sand and clay, either saturated with water or not. Equivalent thermal properties have been derived that allow reproducing in a simple conductive model the temperature distributions measured on the steel piles. Modelling the whole sequence of events from erection of the structure to failure under fire requires the successive application of 2 different software, RIDO that reproduces the evolution of the displacement...
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The paper is given of an extended model for concrete in compression at elevated temperature that incorporates elastic, plastic and creep strain as a function of temperature and stress history. The mechanical strain calculated as a... more
The paper is given of an extended model for concrete in compression at elevated temperature that incorporates elastic, plastic and creep strain as a function of temperature and stress history. The mechanical strain calculated as a function of elastic strain, plastic strain and thermal induced strain. The thermal induced strain is relative independent compared to dependence of Young’s Modulus by load history. Actually the term comprises elastic, plastic and (pure) transient creep strains as we will show. A comparison is given between experimental results with cylindrical specimens and calculated results.
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This paper describes a novel methodology for conducting stable hybrid fire testing (HTF). During hybrid fire testing, only a part of the structure is tested in a furnace while the reminded structure is calculated separately, here by means... more
This paper describes a novel methodology for conducting stable hybrid fire testing (HTF). During hybrid fire testing, only a part of the structure is tested in a furnace while the reminded structure is calculated separately, here by means of a predetermined matrix. Equilibrium and compatibility at the interface between the tested “physical substructure” and the “numerical substructure” is maintained throughout the test using a dedicated algorithm. The procedures developed so far are sensitive to the stiffness ratio between the physical and the numerical substructure and therefore they can be applied only in some cases. In fire field, the stiffness of the heated physical substructure may change dramatically and the resulting change in stiffness ratio can lead to instability during the test. To overcome this drawback, a methodology independent of the stiffness ratio has been developed, inspired from the Finite Element Tearing and Interconnecting (FETI) method, which has been originall...