Browsing by Author "Bouchair, Abdelhamid"
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- Etude par simulation numérique du comportement des portiques métalliques en situation d’incendiePublication . Benlakehal, Nourredine O.; Lamri, Belkacem; Kada, Abdelhak; Mesquita, L.M.R.; Bouchair, AbdelhamidLes structures en portiques métalliques à double versants sont largement utilisées dans les bâtiments industriels pour des raisons pratiques d’exploitation, de durabilité et de rentabilité. Cependant le matériau acier quoi que ductile, il reste vulnérable aux excès de températures. Les récents événements d’incendies concernant les structures et bâtiments industriels de Sonatrach, à Alger dans une zone urbaine ou à Skikda dans une zone industrielle, nous rappellent le danger réel et le risque potentiel des incendies. Les nouvelles normes Européennes définissent des exigences actives et passives concernant le comportement au feu des hangars industriels. L’objectif de ce travail est d’étudier, par des simulations numériques, le comportement des portiques métalliques à double versants sous différents scénarios d’incendie. L’analyse numérique par la MEF et utilisant le logiciel ANSYS est considérée afin d’évaluer la résistance de ces structures et de rationaliser leur protection au feu. Une analyse, utilisant les non linéarités géométrique et matérielle, est conduite avec une variation progressive des températures jusqu’à la ruine. Différents taux de chargement ainsi que différents scénarios de feu seront utilisés pour évaluer la température critique ainsi que les déplacements des portiques en fonction de l’évolution de la température. Les résultats du modèle numérique sont comparés à ceux calculés par les méthodes simplifiées de l’Eurocode 3
- Finite element analysis of steel beams with web apertures under fire condictionPublication . Kada, Abdelhak; Lamri, B.; Mesquita, L.M.R.; Bouchair, AbdelhamidThis work is intended to analyse the behaviour steel beams with apertures under high temperatures rise due to fire using finite elements simulations with ANSYS software. It includes a structural fire analysis and a comparative study of cellular and castellated steel beams which takes into account transient temperature effect, material and geometric non-linear behaviour. FE models which estimate limiting time, mid-span deflection and failure temperature are presented for hexagonal and circular types of web opening shapes under several uniform load levels. The study shows that for any beam with closely spaced openings failure in fire will in most cases be caused by failure of the steel web. The numbers of web-openings and cells as well as their shapes are critical for the behaviour of castellated sections and cellular beams under fire condition.
- Finite element investigation on the behaviour of open-web steel beams subjected to firePublication . Kada, Abdelhak; Lamri, Belkacem; Bouchair, Abdelhamid; Mesquita, L.M.R.This paper presents a numerical investigation on the behaviour of open-web steel beams under high temperatures rise due to fire using finite elements simulations with ANSYS software. Cases of study for solid parent steel elements as well as castellated and cellular beams are considered and take into account uniform and transient temperature rise, material and geometric non-linear behaviour. Input fire is the standard temperature-time curve ISO834 fire model and thermal and mechanical analyses are done using the effect of temperature dependent material properties according to Eurocode3 part1--2 recommendations for mechanical steel properties reduction. FE models which estimate failure temperatures are presented for two most commonly used types of web opening shapes including, hexagonal and circular for simply supported beams under uniformly distributed mechanical loading. The study shows that the numbers of web-openings and cells as well as their shapes are critical for the behaviour of castellated steel beams under fire conditions. Results are related to temperature profiles in steel beam cross-sections, variation of displacements with respect to temperature change and critical temperatures.
- Finite element investigation on the behaviour of structural steel beams subjected to standard & parametric firePublication . Kada, Abdelhak; Lamri, Belkacem; Benlakehal, Nourredine O.; Mesquita, L.M.R.; Bouchair, AbdelhamidThis paper intends to present an investigation of the behaviour of steel beams under high temperatures rise due to fire using finite elements simulations with ANSYS software. Cases of study for solid as well as open web beams are considered and take into account uniform and transient temperature rise, material and geometric non-linear behaviour. Input fire scenarios are standard temperature-time curve ISO834 and parametric compartment fire model based upon Eurocode EN 1991-1-2. For the latter a comparison is made using the experimental results from BRE-Cardington tests data. Thermal and mechanical analysis is done using the effect of temperature dependent material properties and the Eurocode recommendations in estimating reduction mechanical steel properties. Three types of cellular beams are studied and the number of cells is shown to be critical for their behaviour under fire conditions. Results are related to temperature profiles in steel beam cross-sections, variation of displacements with respect to temperature change and critical temperatures.
- On the behaviour of structural steel beams under natural compartment firePublication . Kada, Abdelhak; Lamri, Belkacem; Benlakehal, Nourredine O.; Bouchair, Abdelhamid; Mesquita, L.M.R.Fire is an extreme action, to which a steel structure may be submitted, and therefore, must be designed to resist. Traditionally, the fire resistance of structural steel beams has been determined in standard fire tests, with the temperature-time curveISO834representing more severe heating conditions compared to that which occurs in many typical natural fire compartments.Thereforeto design a steelstructure safely and economically, it is necessary to calculate temperature distribution in steel beamsunder natural fire. In this paper, the temperature profiles in a steel beams under natural fire arestudied first, using spread-sheets written by authorsand compared to standard fire. Secondly, twoCardington compartment corner office tests are highlighted,and analysis of primary and secondary steel beamsis presented.Simple theoretical natural fire models based on Eurocode EN 1991-1-2 parametric compartment fire are used and a comparison is made using the experimental results from tests conducted at Cardington research centre, UK. Compartment temperatures and cross-section temperature distribution respectively demonstrates that analytical fire models and experimental results are in good agreement in the case of timber cribs fire load.
- Simulation numerique du comportement non-lineaire des portiques métalliques en situation d’incendiePublication . Benlakehal, Nourredine O.; Lamri, Belkacem; Abdelhak, Kada; Bouchair, Abdelhamid; Mesquita, L.M.R.Pour des raisons pratiques d’exploitation et de durabilité, les bâtiments industriels, sont dans la majorité des cas conçu en charpente métallique. Cependant le matériau acier quoi que ductile, il reste vulnérable aux excès de températures. Les récents événements d’incendies concernant les structures et bâtiments industriels de Sonatrach, à Alger dans une zone urbaine ou à Skikda dans une zone industrielle, nous rappellent le danger réel et le risque potentiel des incendies. Les nouvelles normes Européennes définissent des exigences actives et passives concernant le comportement au feu des bâtiments industriels. L’objectif de ce travail concerne l’étude du comportement non-linéaire des structures industrielles en acier selon plusieurs scénarios de feu. L’analyse numérique par la MEF et utilisant le logiciel ANSYS est considérée afin d’évaluer la résistance de ces structures et d’optimiser leur protection au feu. Une analyse, utilisant les non linéarités géométrique et matérielle, est conduite avec une variation progressive des températures jusqu’à la ruine. Différents taux de chargement ainsi que différents scénarios de feu seront utilisés pour évaluer la température critique ainsi que les déplacements des portiques en fonction de l’évolution de la température.
- Time resistance of industrial steel portal frames with haunches under firePublication . Benlakehal, Nourredine O.; Kassoul, A.; Piloto, P.A.G.; Bouchair, AbdelhamidTo protect human lives and prevent against failure of structures, the collapse of industrial buildings under fire should always occur inward with a minimum failure time. The objective of this paper is to investigate the behaviour of industrial steel portal frames with haunches in fire situation. The structure is studied using finite element software ANSYS with an uncoupled thermal and mechanical analysis. The inclination angle of the rafter and the haunch’s length for the portal frame are taken as variables. A comparative study of the numerical simulations and the simplified method (R15) show a close agreement between the two analyses according to the failure time.