Research Interests:
Research Interests:
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...
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...
Research Interests:
Research Interests:
... 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. ...
Research Interests:
... 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. ...
Research Interests:
Research Interests: Fire and Fire Resistance
Research Interests: Beam and Fire Resistance
Research Interests:
The specimens referred to in this recommendation may be laboratory cast, field cast or taken as cores, m the case of an accompanying test under identical conditions as the specimen of the belonging test; they should conform to the... more
The specimens referred to in this recommendation may be laboratory cast, field cast or taken as cores, m the case of an accompanying test under identical conditions as the specimen of the belonging test; they should conform to the recommendations given below,
Research Interests:
... F. WEISE, B. MENG and U. SCHNEIDER Fire Induced Transient Creep Causing Stress ... J. GALES, L. BISBY and C. MACDOUGALL Experimental Study of Aging Effects on Insulative ... 751 E. ANNEREL and L. TAERWE Behaviour at High Temperature... more
... F. WEISE, B. MENG and U. SCHNEIDER Fire Induced Transient Creep Causing Stress ... J. GALES, L. BISBY and C. MACDOUGALL Experimental Study of Aging Effects on Insulative ... 751 E. ANNEREL and L. TAERWE Behaviour at High Temperature of Concretes Prepared with ...
Research Interests:
Parametrical Study on the Behaviour of Steel and Composite Cellular Beams Under Fire Conditions O. VASSART, CG BAILEY, G. BIHINA, M. HAWES, A. NADJAI, C. PEIGNEUX, WI SIMMS and J.-M. FRANSSEN ABSTRACT This paper describes an extensive... more
Parametrical Study on the Behaviour of Steel and Composite Cellular Beams Under Fire Conditions O. VASSART, CG BAILEY, G. BIHINA, M. HAWES, A. NADJAI, C. PEIGNEUX, WI SIMMS and J.-M. FRANSSEN ABSTRACT This paper describes an extensive parametric study on the ...
Research Interests:
The information that is necessary to perform the fire design of a structure made of a particular material, say a steel structure, is: a) The bases of design, stated in EN 1990. b) The mechanical actions, ie the forces, acting on the... more
The information that is necessary to perform the fire design of a structure made of a particular material, say a steel structure, is: a) The bases of design, stated in EN 1990. b) The mechanical actions, ie the forces, acting on the structure in the fire situation. Some information is ...
Research Interests:
Research Interests:
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.
Research Interests:
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
Research Interests:
The basic equations, the limitations and the main features of the parametric fire proposed in Annexe B of Eurocode 1 are given. 48 experimental fire tests are used to assess the validity of this model. The model has been applied to these... more
The basic equations, the limitations and the main features of the parametric fire proposed in Annexe B of Eurocode 1 are given. 48 experimental fire tests are used to assess the validity of this model. The model has been applied to these tests and the comparison has been made, for each test, on the maximum temperature in the air and on the maximum temperature calculated in 2 hypothetical steel sections, one thermally protected and one unprotected. The agreement is very poor for the air and for the unprotected steel temperature, and somewhat better for the protected steel temperature. Some proposals are made which allow to improve the agreement, while keeping the same expressions for the parametric fire. These modifications concern the equivalent thermal properties of multi material walls, and the introduction of a minimum duration of the fire and a of a ventilation effect in case of fuel-bed controlled fires.
Research Interests:
Large-scale fire tests and observations of actual building fires have shown that the fire performance of composite steel framed buildings is much better than is indicated by fire resistance tests on isolated elements. This contribution... more
Large-scale fire tests and observations of actual building fires have shown that the fire performance of composite steel framed buildings is much better than is indicated by fire resistance tests on isolated elements. This contribution presents application of a simple design method, so-called FRACOF concept, for the analysis of non-sway steel-framed buildings with composite floors. Starting point were the outstanding results obtained in the BRE Cardington large-scale building fire test programme carried out during 1995 and 1996. The method was further validated by large-scale standard furnace tests in 2008 and 2009, as well as with natural fire tests in 2010. A recent test has also shown the possibility of application of this concept to composite floors with castellated beams. The recommendations are in line with the reliability level imposed by current design rules and are limited to structures similar to that tested. The method permits designers to spare the fire protection for th...
Abstract. The paper presents the assumptions and the issues that arise when developing an integrated modelling methodology between a Computational Fluid Dynamics (CFD) software applied to compartment fires and a Finite Element (FE)... more
Abstract. The paper presents the assumptions and the issues that arise when developing an integrated modelling methodology between a Computational Fluid Dynamics (CFD) software applied to compartment fires and a Finite Element (FE) software applied to structural systems subjected to fire. In particular, a weak coupling approach used to simulate a fire exposed structure by modelling the fire development in the compartment, the heat penetration in the structure and the mechanical response is described. The advantages and the disadvantages of such a technique are highlighted compared to a full coupling that conversely takes into account all mutual interactions. The favourable aspect of computing the thermal response of the structure in the FE model in order to avoid modelling the structure in the CFD model is underlined, namely a sensitive reduction of computational demand. Finally, a practical application is presented. 1
Research Interests:
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
Research Interests:
Massive concrete structures submitted to fire usually exhibit a satisfactory behaviour. However, in some cases, spalling phenomenon's may cause a fast and significant decrease of the resistance of the affected elements. Tunnels are... more
Massive concrete structures submitted to fire usually exhibit a satisfactory behaviour. However, in some cases, spalling phenomenon's may cause a fast and significant decrease of the resistance of the affected elements. Tunnels are often exposed to heavy fire loads and may lose some concrete layers on their heated faces. The disappearance of the cover makes the reinforcement bars unprotected. In this paper, it is shown how the code SAFIR may be used to perform a risk analysis by integrating acceptable values of spalling. This concept will be illustrated by examining a particular application.
Research Interests:
ENV 1992-1-2, the fire part of the concrete Eurocode, proposes different tables for the design of simple concrete elements submitted to the ISO fire. Table 4.1 is the table valid for concrete columns. For six fire resistance times Rf =... more
ENV 1992-1-2, the fire part of the concrete Eurocode, proposes different tables for the design of simple concrete elements submitted to the ISO fire. Table 4.1 is the table valid for concrete columns. For six fire resistance times Rf = 30, 60, 90, 120, 180 and 240 minutes, and for three load ratio μfi = 0.2, 0.5 and 0.7, an acceptable solution is given in term of the minimum dimension of the section bmin and axis distance a from the re-bar to the edge of the section. The application of this table is not as easy as one could believe at first glance especially when it comes to assessing the fire resistance time of existing elements which are different from the recommended solutions. This is because a double interpolation has to be done, on Rf and on μfi, because the criteria is based on 2 different variables, bmin and a, and because the load ratio is not available from the room temperature design (not to mention the complication created by clause 4.2.3 (6)). In this paper, a graphic i...
Research Interests:
Research Interests:
Research Interests:
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...
Research Interests:
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...
Research Interests:
The paper presents the assumptions and the issues that arise when developing an integrated modelling methodology between a Computational Fluid Dynamics (CFD) software applied to compartment fires and a Finite Element (FE) software applied... more
The paper presents the assumptions and the issues that arise when developing an integrated modelling methodology between a Computational Fluid Dynamics (CFD) software applied to compartment fires and a Finite Element (FE) software applied to structural systems subjected to fire. In particular, a weak coupling approach used to simulate a fire exposed structure by modelling the fire development in the compartment, the heat penetration in the structure and the mechanical response is described. The advantages and the disadvantages of such a technique are highlighted compared to a full coupling that conversely takes into account all mutual interactions. The favourable aspect of computing the thermal response of the structure in the FE model in order to avoid modelling the structure in the CFD model is underlined, namely a sensitive reduction of computational demand. Finally, the study is enriched by an application of this methodology that concerns the simulation of a pool fire in an open...
Research Interests:
Research Interests:
Research Interests:
The local buckling capacity of fire exposed thin-walled steel cross sections is affected by the reduction in strength and stiffness due to elevated temperatures and the amplitude of the initial local imperfections. A usual method to... more
The local buckling capacity of fire exposed thin-walled steel cross sections is affected by the reduction in strength and stiffness due to elevated temperatures and the amplitude of the initial local imperfections. A usual method to estimate this capacity is the simulation of isolated plates (web: four sides simply supported plate, flange: three sides simply supported plate) that are subjected to in-plane compression until instability is observed. Several researchers have proposed design methods to calculate the capacity of these steel members at elevated temperatures based on isolated plate analysis, but they used different methodologies. This variability in hypotheses happens because there is no clear provision defining the numerical modeling procedure for fire design of steel plates in the codes (European or US). The paper proposes a methodology for finite element simulation of thin plates at elevated temperatures and its governing factors (amplitude of initial local imperfection...
Research Interests:
SAFIR is a finite element program for the thermal and mechanical analysis of structures submitted to fire. Usually, thermal calculations are run in a first step to determine the temperatures in the structure subjected to fire. In a second... more
SAFIR is a finite element program for the thermal and mechanical analysis of structures submitted to fire. Usually, thermal calculations are run in a first step to determine the temperatures in the structure subjected to fire. In a second step, mechanical analyses are performed to determine the time when collapse will occur. In case of mechanical analysis, different elements are available in SAFIR : truss, beam and shell. The shell element in SAFIR was a triangle with 6 nodes. It gave good results except in case of ‘membrane bending’ where the answer was too stiff. Furthermore, this element was heavy to use because 3 nodes had 6 DOF and the 3 others had only 1 DOF. In order to improve SAFIR, it has been decided to introduce a new quadrangular element to eliminate the over-stiffness of the triangular element in case of ‘membrane bending’. This element has been taken from the room temperature program FINELG (developed by de Ville at the University of Liege and the Bureau d’Etudes Grei...
Research Interests:
The use of slender steel sections has increased in recent years because they provide excellent strength to weight ratio. Yet, a major issue with slender sections is local buckling in compression zones. Several researchers have proposed... more
The use of slender steel sections has increased in recent years because they provide excellent strength to weight ratio. Yet, a major issue with slender sections is local buckling in compression zones. Several researchers have proposed design methods at elevated temperatures based on the effective width approach to calculate the capacity of the plates that compose these steel members, but this approach is not easily compatible with the implementation and use in Bernoulli beam elements. Another approach is the development of a stress based model, i.e. an “effective” constitutive law of steel. This approach was proposed previously by Liege University researchers for slender steel members exposed to high temperatures, and implemented within the framework of fiber type Bernoulli beam elements; however it was giving overly conservative results. This paper presents an improved temperature-dependent constitutive model for steel that accounts for local instabilities using the stress based m...
Research Interests:
Research Interests:
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