References of "Franssen, Jean-Marc"
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See detailConsideration of local instabilities in beam finite elements by means of effective constitutive laws
Franssen, Jean-Marc ULg; Cowez, Baptiste ULg

in Fontana, A; Frangi, A; Knobloch, M (Eds.) Proceedings of the 7th International Conference on Structures in Fire (2012, June 06)

In the fire situation, Bernoulli beam finite elements are the workhorse used in the general calculation model for simulating the behaviour of the structure. Such finite elements treat all sections as ... [more ▼]

In the fire situation, Bernoulli beam finite elements are the workhorse used in the general calculation model for simulating the behaviour of the structure. Such finite elements treat all sections as class 1 (stocky) sections whatever the slenderness of the plates that make the section, allowing the development of a full plastic stress distribution in the section which leads to complete plastic redistribution in the structure. This type of element is thus not adapted for modelling structures that contain slender sections of class 2, 3 or 4. This document presents a new approach to take into account local instabilities using beam finite elements. The new approach is based on an effective constitutive law of steel. The effective law is not symmetrical with respect to tension and compression because, in tension, the stress-strain relationship is not modified whereas, in compression, the stress-strain relationship is modified. [less ▲]

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See detailFire analysis of a new steel bridge
Tonicello, Eric; Desanghere, Sylvain; Vassart, Olivier et al

in Fontana, Mario; Frangi, Andrea; Knobloch, Markus (Eds.) Proceedings of the 7th International Conference on Structures in Fire (2012, June 06)

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 ... [more ▼]

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. [less ▲]

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See detailDevelopment of an interface between CFD and FE software
Tondini, Nicola; Vassart, Olivier; Franssen, Jean-Marc ULg

in Fontana, Mario; Frangi, Andrea; Knobloch, Markus (Eds.) Proceedings of the 7th International Conference on Structures in Fire (2012, June 06)

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 ... [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. 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. [less ▲]

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See detailSimple equations for the calculation of the temperature within the cross-section of slim floor beams under ISO Fire
Zaharia, Raul; Franssen, Jean-Marc ULg

in Steel and Composite Structures (2012)

The calculation of fire resistance for a composite structural element comprises the calculation of the temperature within its cross-section and of the load bearing capacity, considering the evolution of ... [more ▼]

The calculation of fire resistance for a composite structural element comprises the calculation of the temperature within its cross-section and of the load bearing capacity, considering the evolution of the steel and concrete mechanical properties, function of the temperature. The paper proposes a method to calculate the bending capacity under ISO fire, for Slim Floor systems using asymmetric steel beams, with a wider lower flange or a narrow upper flange welded onto a half hot-rolled profile. The temperatures in the cross-section are evaluated by means of empirical formulas determined through a parametrical analysis, performed with the special purpose non-linear finite element program SAFIR. Considering these formulas, the bending capacity may be calculated, using an analytical approach to determine the plastic bending moment, for different fire resistance demands. The results obtained with this simplified method are validated through numerical analysis. [less ▲]

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See detailBranveiligheid - Brandveiligheid en berekening van de brandwerendheid van staalconstructies voor gebouwen volgens Eurocode 3
Cajot, Louis-Guy; Debruyckere, Rik; Franssen, Jean-Marc ULg

Book published by Infosteel (2012)

Dit boek behandelt in de eerste drie hoofdstukken het onderwerp brandveiligheid en de berekening van de brandwerendheid van staalconstructies voor gebouwen volgens Eurocode 3. Hoofdstuk 1 omschrijft de ... [more ▼]

Dit boek behandelt in de eerste drie hoofdstukken het onderwerp brandveiligheid en de berekening van de brandwerendheid van staalconstructies voor gebouwen volgens Eurocode 3. Hoofdstuk 1 omschrijft de doelstellingen van brandveiligheid aan de hand van het gedrag van een brand en bespreekt de maatregelen die een ontwerper kan nemen om te voldoen aan de eisen voor brandveiligheid en de wettelijk eisen. Hoofdstuk 2 gaat over het berekenen van de brandwerendheid van een staalconstructie met betrekking tot bezwijken. Een eenvoudig berekeningsmodel volgens Eurocode 3 wordt besproken en is geschikt voor trekstaven, niet-kipgevoelige liggers, kolommen én kipgevoelige liggers. Voor de berekening van geïntegreerde liggers, zowel onbekleed als bekleed wordt een geavanceerd rekenmodel gebruikt en wordt tevens een alternatieve vereenvoudigde methode voorgesteld. Hoofdstuk 3 behandelt het onderwerp fire safety engineering; een relatief nieuw vakgebied, waarbij fysische modellen worden gebruikt om het gedrag van een brand – en het effect hiervan op bouwwerken en de gebruikers – te beschrijven. Er worden vier situaties besproken die met fire safety engineering in de praktijk al zijn te berekenen: lokale branden, compartimentsbranden (zonder én met flashover), staalconstructies die zich buiten het gebouw bevinden in de buitenlucht én het systeemgedrag van een staalconstructie. Dit laatste wordt geillustreerd aan de hand van een staalplaat-betonvloer waarbij het membraaneffect in acht wordt genomen. Hoofdstuk 4 tenslotte bevat dertien ontwerptabellen voor het eenvoudig bepalen van een aantal rekenparameters zoals de afname van de effectieve vloeigrens en de elasticiteitsmodulus, de reductiefactor op de belastingen bij brand, de profielfactoren voor I-profielen, de staaltemperatuur na een bepaalde tijd (in functie van de profielfactor) en de kritieke staaltemperatuur voor kolommen (in functie van de benuttinggraad en slankheid). [less ▲]

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See detailDevelopment of an interface between a CFD software and a FE software for compartment fires
Tondini, Nicola; Franssen, Jean-Marc ULg

in Costruzioni Metalliche (2012), 3

The article 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 ... [more ▼]

The article 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. In particular, a weak coupling methodology 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. A practical application is also shown. [less ▲]

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See detailHeat transfer and structural response modelling of concrete filled steel hollow section columns
Binh, Chu Thi; Dotreppe, Jean-Claude ULg; Franssen, Jean-Marc ULg

in Proc; ACOME (2012)

Numerical modelling is a very useful tool to predict the fire resistance of a structure, or to reproduce artificially what has happened during a real fire. SAFIR, a non linear computer code developed at ... [more ▼]

Numerical modelling is a very useful tool to predict the fire resistance of a structure, or to reproduce artificially what has happened during a real fire. SAFIR, a non linear computer code developed at the university of Liege-Belgium, is specifically written for modeling the behavior of structures subjected to fire. It allows a determination of the temperatures in the structure resulting from the fire and, in a subsequent analysis, determination of the successive positions of equilibrium of the structure until collapse. Ten steel hollow section columns filled with self-compacting concrete embedding another steel profile have been tested in the Fire Engineering Laboratory of the University of Liege - Belgium. SAFIR code has been used to simulate the thermal and structural behavior under fire conditions. A good agreement between numerical and experimental results has been obtained. This shows that SAFIR code can predict well the behavior of CFSHS columns subjected to fire. [less ▲]

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See detailTensile membrane action in composite floors subjected to fire
Franssen, Jean-Marc ULg

in Liew, J Y Richard (Ed.) Advances in steel concrete composite and hybrid structures (2012)

The essential features of composite steel concrete beams and slabs are first given for a load bearing mode in one-way bending. The essential features of the two ways acting tensile membrane action load ... [more ▼]

The essential features of composite steel concrete beams and slabs are first given for a load bearing mode in one-way bending. The essential features of the two ways acting tensile membrane action load bearing mode are then explained. Experimental tests that helped understanding and quantifying the tensile membrane action, either small scale or large scale, at room temperature or in fire condition, are summarized. Simple calculation models that have been developed for calculating the load bearing capacity of composite floor under fire are presented. Considerations are given about the requirements for numerical models aiming at simulating the behavior of composite floor systems in the fire situation are given. Finally, an application example is presented of a composite floor system designed by the author in 2007. [less ▲]

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See detailNumerical analysis of stainless steel beam-columns in case of fire
Lopes, Nuno; Vila Real, Paulo; Simoes da Silva, Luis et al

in Fire Safety Journal (2012), 50

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See detailSécurite incendie - Sécurité incendie et calcul de la résistance au feu des bâtiments en acier selon l'Eurocode 3
Cajot, Louis-Guy; Debruyckere, Rik; Franssen, Jean-Marc ULg

Book published by Infosteel (2012)

Ce livre traite, dans ses trois premiers chapitres, de la sécurité incendie et du calcul de la résistance au feu des structures de bâtiments en acier selon l'Eurocode 3. Le chapitre 1 définit les ... [more ▼]

Ce livre traite, dans ses trois premiers chapitres, de la sécurité incendie et du calcul de la résistance au feu des structures de bâtiments en acier selon l'Eurocode 3. Le chapitre 1 définit les objectifs de la sécurité incendie sur la base du déroulement d'un incendie et examine les mesures que le concepteur peut prendre afin de répondre aux exigences de sécurité incendie et aux exigences réglementaires. Le chapitre 2 traite du calcul de la résistance au feu de structures en acier pour ce qui concerne le critère de capacité portante. Un modèle de calcul simple est donné dans les Eurocodes pour les éléments tendus, les colonnes et les poutres soumises ou non au déversement. Pour le calcul des poutres intégrées, qu’elles soient protégées ou non, on peut utiliser un modèle de calcul avancé, mais une méthode alternative simple est décrite dans cet ouvrage. Le chapitre 3 traite de l'ingénierie de la sécurité incendie, une discipline relativement nouvelle qui utilise les modèles physiques pour décrire le déroulement d'un incendie et ses effets sur le bâtiment et ses occupants. On évoque quatre situations qui nécessitent l’utilisation de l'ingénierie de la sécurité incendie, à savoir: les feux localisés, les feux de compartiment (avec ou sans embrasement généralisé), le cas des structures en acier situées à l'extérieur du bâtiment et celui où l’on considère le comportement d’ensemble d’une ossature. Ce dernier cas est illustré par l’étude de l’effet membranaire d’un système de plancher. Enfin, le chapitre 4 contient treize tableaux de dimensionnement qui donnent directement certains paramètres de calcul comme la réduction de la limite d’élasticité efficace, celle du module d’élasticité de l’acier, le niveau de chargement en situation d’incendie, le facteur de massiveté des sections en I, la température atteinte dans l’acier après un certain temps (pour divers valeurs de ce facteur de massiveté) et la température critique des colonnes (en fonction de leur niveau de chargement et de leur élancement). [less ▲]

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See detailLarge-Scale Fire Test of Unprotected Cellular Beam Acting in Membrane Action
Vassart, Olivier; Bailey, C. G.; Hawes, M. et al

in Journal of Structural Fire Engineering (2011), 2(4), 259-268

This paper describes a full scale fire test performed the 27th of February 2010 on a composite floor for analysing the possibility of tensile membrane action to develop when the unprotected steel beams in ... [more ▼]

This paper describes a full scale fire test performed the 27th of February 2010 on a composite floor for analysing 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. The natural fire was created by a wood crib fire load of 700 MJ/m2 and the 9 × 15 m floor survived the fire that peaked at 1000°C and lasted for 90 minutes. Blind predictions of the air temperature development by the software OZone and of the structural behaviour by the software SAFIR which proved quite satisfactory are also described. [less ▲]

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See detail300e conférence du C.E.R.E.S
Courard, Luc ULg; Dehousse, Nicolas ULg; Demonceau, Jean-François ULg et al

Book published by Centre d'Etudes, de Recherches et d'Essais Scientifiques du Génie Civil (2011)

Cette brochure comprend: le mot du président, un historique du CERES, la liste des bulletins, mémoires et conférences du CERES depuis ses origines jusqu'à ce jour, la liste des présidents, secrétaires et ... [more ▼]

Cette brochure comprend: le mot du président, un historique du CERES, la liste des bulletins, mémoires et conférences du CERES depuis ses origines jusqu'à ce jour, la liste des présidents, secrétaires et trésoriers, un mot de conclusions, ainsi que le programme de la manifestation organisée à l'occasion de la trois centième conférence du CERES. [less ▲]

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See detailLe mot du président
Franssen, Jean-Marc ULg

in Courard, Luc; Dehousse, Nicolas; Demonceau, Jean-François (Eds.) et al 300e conférence du C.E.R.E.S (2011)

On discute du rôle du CERES: essentiellement une fenêtre ouverte sur le monde pour nos chercheurs et nos étudiants, un moyen pour le département ArGEnCo de maintenir le contact avec le monde de l ... [more ▼]

On discute du rôle du CERES: essentiellement une fenêtre ouverte sur le monde pour nos chercheurs et nos étudiants, un moyen pour le département ArGEnCo de maintenir le contact avec le monde de l'entreprise. [less ▲]

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See detailNew features in SAFIR: Structural Fire Analysis of a Shell Roof Structure
Gernay, Thomas ULg; Franssen, Jean-Marc ULg

Scientific conference (2011, November 15)

The structural fire analysis of a roof structure made of two concrete shells has been performed with the software SAFIR.

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See detailNew features in SAFIR: Damage-Plastic Multiaxial Model for Concrete
Gernay, Thomas ULg; Franssen, Jean-Marc ULg

Scientific conference (2011, November 15)

The need for robust, reliable multiaxial constitutive relationships for concrete is a challenging issue in structural fire engineering. A new damage-plastic model has been developed to capture the ... [more ▼]

The need for robust, reliable multiaxial constitutive relationships for concrete is a challenging issue in structural fire engineering. A new damage-plastic model has been developed to capture the development of permanent strains and the degradation of elastic properties in concrete subjected to thermo-mechanical loading. This model has been implemented in the software SAFIR for using with SOLID finite elements (multiaxial model) and with SHELL finite elements (plane stress model). [less ▲]

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See detailNew features in SAFIR: Transient Creep in Eurocode Concrete Model
Gernay, Thomas ULg; Franssen, Jean-Marc ULg

Scientific conference (2011, November 15)

A new formulation of the Eurocode 2 concrete model at elevated temperature has been implemented in which the transient creep strain is treated by an explicit term in the strain decomposition. This new ... [more ▼]

A new formulation of the Eurocode 2 concrete model at elevated temperature has been implemented in which the transient creep strain is treated by an explicit term in the strain decomposition. This new model gives the same answer as the Eurocode model when the load and the temperature increase, but the new model is better than the Eurocode model at capturing the concrete behavior when the load or the temperature decrease owing to the explicit transient creep term. This new concrete model, called Explicit Transient Creep Eurocode model (ETC), has been implemented in the software SAFIR. [less ▲]

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See detailDevelopment of an FDS-SAFIR interface
Tondini, Nicola; Franssen, Jean-Marc ULg

Scientific conference (2011, November 15)

A weak coupling strategy from CFD models to F.E. models is being developed on the base of an interface file. The software FDS and SAFIR are used in the applications.

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See detailFull-scale fire test on a composite floor slab incorporating long span cellular steel beams
Nadjai, Ali; Bailey, Colin; Vassart, Olivier et al

in Structural Engineer (2011), 89(21), 18-25

As part of an international major research initiative, dealing with the behaviour of long span cellular beams in steel framed buildings under fire, a large-scale fire test incorporating 15m long cellular ... [more ▼]

As part of an international major research initiative, dealing with the behaviour of long span cellular beams in steel framed buildings under fire, a large-scale fire test incorporating 15m long cellular beams was carried out. The test incorporated unprotected secondary cellular steel beams acting compositely with the supporting floor slab. The floorplate in its entirety was designed to carry the load with unprotected beams, when subjected to a severe fire, by utilising membrane action of the floor slab. The overall structure performed very well supporting the full applied static load for the duration of the test. The unprotected cellular steel beams were subjected to distortional buckling, with only the top tee providing any support through catanary action. The test supported the assumptions adopted in the structural design approach and provided an accurate estimate of the strength of the floorplate. Comparison of the recorded time-temperature relationship of the fire with the design method presented in the Eurocodes shows that the code under-predicts the severity of the fire, although this was compensated to some extent by the conservative assumptions embedded within the structural model. [less ▲]

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See detailCollapse of concrete columns during and after the cooling phase of a fire
Dimia, Mohamed Salah; Guenfoud, Mohamed; Gernay, Thomas ULg et al

in Journal of Fire Protection Engineering (2011), 21(4), 245263

This paper presents a study performed on the collapse of reinforced concrete columns subjected to natural fire conditions during and after the cooling phase of the fire. The aim is, first, to highlight ... [more ▼]

This paper presents a study performed on the collapse of reinforced concrete columns subjected to natural fire conditions during and after the cooling phase of the fire. The aim is, first, to highlight the phenomenon of collapse of concrete columns during and after the cooling phase of a fire and then, to analyze the influence of some determinant parameters. The main mechanisms that lead to this type of failure are found to be the delayed increase of the temperature in the central zones of the element and the additional loss of concrete strength during the cooling phase of the fire. A parametric study is performed considering different fires and geometric properties of the column. This shows that the most critical situations with respect to delayed failure arise for short fires and for columns with low slenderness or massive sections. [less ▲]

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See detailFRACOF: Fire resistance assessment of partially protected steel-concrete composite floors
Zanon, Riccardo; Sommavilla, Mauro; Vassart, Olivier et al

in De Luca, Antonello (Ed.) XXIII Giornate italiane della costruzione in acciaio (2011, October 12)

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 ... [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 the framing elements for which it is not needed by keeping the same safety requirement than traditional codes. [less ▲]

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