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Academic literature on the topic 'Bois d'oeuvre – Essais de comportement au feu'
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Dissertations / Theses on the topic "Bois d'oeuvre – Essais de comportement au feu"
Nguyen, Manh-Hung. "Évaluation des performances de protections passives au feu pour les structures métalliques." Electronic Thesis or Diss., Université Clermont Auvergne (2021-...), 2023. http://www.theses.fr/2023UCFA0046.
Full textSteel-timber hybrid structures are becoming more and more common in the construction industry. They offer high practical advantages as sustainable solutions with high load-bearing capacities and fire resistance. However, due to steel thermal conductivity and the decrease of mechanical performance with high temperatures, steel structures need to be protected in case of fire. Wood is occasionally used as passive protection of steel to maintain its mechanical strength as long as possible with the aim to prevent structural collapse under fire. This thesis aims to analyse the thermal behaviour of hybrid steel-timber elements through experimental tests and numerical modelling. Experiments in the furnace are performed to obtain the evolution of temperature on the steel profile surfaces and inside the timber element. Thus, thermocouples are installed on the steel profile surface and different depths of timber elements. The fire tests were performed on various steel-timber combinations using T and I steel cross-sections with various wood species. A high-temperature furnace up to 1200 °C built in the laboratory was used. The results show that wood provides significant protection to the steel cross-section mainly the fully encapsulated IPE profile. Wood behaves as an insulating material that significantly reduces the temperature rise in steel. This solution contributes to the development of passive protection of steel structures using bio-based materials. The experimental results are compared to those obtained through thermal simulations using Abaqus software. The comparison shows that the numerical model can be used to evaluate the temperature increase in the steel element protected by timber in high-temperature conditions
Fernandez, Cristian. "Caractérisation et modélisation du comportement au feu de poutres en bois lamellé collé." Nancy 1, 2006. http://www.theses.fr/2006NAN10099.
Full textWood is increasingly being used as building rnaterial due to its specific characteristics, such as its high insulating capacity given by its low thermal conductivity. Nowadays, wood may be considered as an answer to the cUITent energy cri sis, resulting in cost reduction in energy consumption. Wood is classified as a combustible material, which makes us doubt about its structural tire resistance. However, contrarily to !bis idea and spite of its classification, wood provides an excellent tire resistance. It bas long been recognized that under a tire situation, a wood structure loses resistance more slowly than a steel or concrete structure. The particular context of this study relates to tire applied to glulam. Currently, the most used adhesives in the glulam industry are: Resorcinol-Formaldehyde, Phenol-Resorcinol-Formaldehyde, Urea-Formaldehyde, and MelamineUrea-Formaldehyde. The main problem arising from these adhesives is their two-component fonnulation (adhesive and hardening), making their usage more complicated. Moreover, wood bas to be dried before gluing, which in turn increases the costs and building time. Ln order to solve these inconveniences, there are currently other solutions in the market, e. G. Polyurethane adhesives consist of only one liquid component applied directly on wood even if it is wet. However, this kind of adhesive shows a high level of creep at high temperatures, which rnay lead to a dangerous situation during a tire. Ln the development of !bis thesis, we characterized the behavior of structural polyurethane adhesives under tire, considering as parameter for comparison the most used adhesives, i. E. Phenol-Resorcinol-Formaldehyde and MelamineUrea-Formaldehyde. As a first stage we characterized the different adhesives subject to high temperatures (between 30°C and 250 °C). As a second stage we established the tire behavior of glulams under the different studied adhesives. For !bis, we chose to perfonn tests with a radiant panel at constant flow (15, 25, 45 and 60 kW/m2). The main result was that the kind of adhesive used in glulams bas no influence on tire resistance. The final stage of fuis study consisted on modeling the different occurring phenomena: A thermal model through a finite element allowed to follow-up in time the temperature distribution in the glulam transversal section subject to a heat flow. By integrating the stiffness database and the elasticity modulus resulting from the creep tests, we have been able to predict the creep behavior and failure time for a glulam subject to a temperature flow that simulates a tire. The results agree with the tests and show that the kind of adhesive bas no influence on tire resistance as the char layer that forms in the glulam surface is a good insulator that limits the depth of the wood darnaged by temperature and thus, its loss of mechanical resistance
Thi, Van Diem. "Modélisation du comportement au feu des structures en bois." Thesis, Université de Lorraine, 2017. http://www.theses.fr/2017LORR0363/document.
Full textNumerical modelling of timber structures in fire conditions requires the knowledge of the variation with temperature of the physical properties of the wood material (the thermal conductivity, the specific heat and the density) in order to take into account the thermal degradation of wood under high temperatures during the drying, pyrolysis and combustion phases, as well as the temperature profiles in the thickness of the surfaces exposed to fire. In particular, this work focusses on the thermomechanical behaviour of timber. The heat transfer analysis is described by the standard equations of heat conduction. It includes the three modes of heat transfer: conduction, radiation and convection. The structural response is modelled within the framework of thermodynamics of irreversible processes using the notion of state variables. It takes into account the coupling between the orthotropic elastic behaviour, the anisotropic plastic behaviour with isotropic nonlinear hardening, and isotropic damage. The numerical integration of the equilibrium equations is carried out with an iterative implicit scheme combining the technique of radial re- turn with the reduction of the number of equations. The thermomechanical coupling is carried out according to the approach recommended by Eurocode 5 for the fire resistance of timber structures by applying the reduction factor Kθ to the strength of a softwood. The theoretical aspects and boundary conditions associated with the thermomechanical model are also discussed. The parameters of the model are identified with experimental data obtained from actual fire tests available in the literature. Several comparative applications are carried out. The finite element model accurately reproduces the distribution of the temperature profile in the thickness of timber planks, the formation of the charred layer, and the evolution of the mechanical resistance during exposure to fire
Dias, de Moraes Poliana. "Influence de la température sur les assemblages bois." Nancy 1, 2003. http://www.theses.fr/2003NAN10157.
Full textThe more generalized use of wood for building raises concern for fire safety. The current standards require the structure stability for a minimum time to ensure the building evacuation and the fire fight. Considering that the fire endurance of wood is well-known, the stability requirement is mainly reduced to the understanding of the behaviour of wood joints on fire. The aim of this work is to study the behaviour of single-dowel timber joints and it is divided into three parts. The first part is a study of the influence of temperature on the modulus of elasticity and on the embedding strength in a range between 20 and 300 °C. In the second part the wood charring and the influence of a metallic dowel embedded in wood, is studied. In the third part, the fire behaviour of single-dowel wood joints is tackled. The first two studies have provided mechanical and thermal data to allow the development of a model to simulate the joint behaviour and its fire endurance before fracture
Terrei, Lucas. "Comportement au feu du matériau bois : auto-inflammation, dégradation et auto-extinction." Electronic Thesis or Diss., Université de Lorraine, 2020. http://www.theses.fr/2020LORR0118.
Full textThe construction of positive energy and low carbon footprint buildings is a real response to the environmental issues and challenges of the coming decades. An increasing number of high-rise building construction projects made largely of wood are either under study or under construction. A key issue for the construction of such buildings is the fire behavior of these structures. Indeed, when the wood is subjected to a high heat flux, it will degrade and it can self-ignite. Conversely, in certain conditions, wood can self-extinguish. However, the bibliography shows the disparity concerning experimental results for a same material subjected to a given test such as the cone calorimeter. The results on the wood extinction remain limited in view of recent research carried out on this phenomenon. The aim of the thesis is to experimentally study the self-ignition, degradation and self-extinction of the wood material used in buildings. For this, many tests at different scales have been performed to examine the ability of the wood material to self-ignite or self-extinct under prescribed conditions. A total of 600 tests, were performed in vertical orientation and allowed to consolidate results with a statistical approach. A dedicated experimental setup has been deployed on each experimental device studied: an infrared camera providing to measure the surface temperature of the samples when they are subjected to a heat flux, two fast cameras (visible and infrared) in order to record the location and the auto-ignition mechanisms and very thin thermocouples embedded in the wood to measure the temperature evolution in the material according to fixed conditions. Results showed that for the auto-ignition (i.e. without pilot), the notion of ignition temperature of the material could be questionable when the ignition occurs at short times. Indeed, the flame appearance is, in most of the experiments, at a distance far from the exposed surface to the heat flux. The ignition mechanisms do not depend on the surface temperature but on the gas / air mixing conditions as well as the mixture temperature. The auto-ignition surface temperature makes therefore sense only for long auto-ignition times, for which ignition occurs close to the surface. The samples degradation depends on many factors: sample orientation, sample humidity, wood species, oxygen concentration in the atmosphere. The effect of these parameters was considered in this work. A particular attention was focused on the establishment of a metrology aimed at obtaining precise and accurate measurements. Very thin thermocouples, embedded in the sample and oriented parallel to the isotherms allow a better estimation of the temperature and were therefore used. Finally, a new experimental device based on two cones calorimeter arranged on a sliding table system was set up and made it possible to determine simple criteria for wood self-extinguishment at small scale
Audebert, Maxime. "Approche expérimentale et modélisation du comportement au feu d'assemblages bois sous différents types de solliciations." Thesis, Clermont-Ferrand 2, 2010. http://www.theses.fr/2010CLF22086.
Full textThe knowledge of the behavior of structures under fire conditions is essential to control the risks during a fire. As timber is a combustible material, fire safety is of main importance for the development of its use in buildings. Although experimental and numerical studies exist in the literature, their number still limited regarding the variety of the configurations and the complexity of the mechanical behavior of the connections. Among the various structural components, the joints are characterized by a complex thermomechanical behavior due mainly to the geometrical configuration combining various materials (steel and timber). They govern the load-carrying capacity of the structure and its safety, as well in normal conditions as in fire situation. Due to their complex geometrical, physical and material configurations, the behavior of the connections in fire is one of the more difficult to predict. The development of generalized models requires the combination of research based both on the experimental results given by full scale tests and the development of sophisticated numerical models validated on these tests.The experimental results of tests realized on timber-to-timber and steel-to-timber connections used as a basis for the validation of the numerical models are presented. They concern tests of longitudinal and transversal tension and flexion under normal conditions and under standardized thermal actions. The thermomechanical analysis of the connections is made from two different three-dimensional meshings for the thermal and mechanical calculations. The thermal model is continuous to take account of the thermal continuity between the joint components. The mechanical model is discontinuous to consider the contact evolution between the joint components. The thermal model isused to predict the evolution of the temperature field inside the joint depending on the gas temperature. It is validated on the basis of measured temperatures during fire tests. The mechanical model is validated by comparison with the experimental results of joints in normal conditions. It allows the analysis of the distribution of stresses within the joints. The influence of various criteria to represent the mechanical behavior of timber is also studied. Finally, the thermomechanical model, based on previous both models, allowed to predict the behaviorof the tested connections in fire situation. The thermo-mechanical model is validated considering the fire resistance duration of some joints. This duration is defined by means of displacement-time curves obtained by the numerical model. The models showed a good capacity to simulate the failure times of the timber joints in fire situations. The application of the model gave the possibility to analyse the load distribution among the fasteners of the studied joints.The model developed in this work represents well the thermomechanical behavior of the tested connections. These developed and tested models can be used as general tool to analyze the behavior of a large variety of joint configurations to constitute a data base that can be used in safe and economic practice of fire engineering of wood joints
Laplanche, Karine. "Etude du comportement au feu des assemblages de structures bois : approche expérimentale et modélisation." Phd thesis, Université Blaise Pascal - Clermont-Ferrand II, 2006. http://tel.archives-ouvertes.fr/tel-00693999.
Full textBéreyziat, Antoine. "Étude du comportement thermomécanique de poutres mixtes acier-bois en situation d’incendie." Thesis, Ecully, Ecole centrale de Lyon, 2022. http://www.theses.fr/2022ECDL0005.
Full textTimber-steel hybridization has great potential, because steel and timber component can reinforce each other, timber can be used to protect steel from fire, and the non-combustibility of steel can be used in an advantageous way. However, this form of hybridization is not widespread despite recent developments in the use of timber for multi-story buildings. Therefore, it is proposed to study composite beams made from timber and steel combined in such a way that the best possible performances are achieved, in normal and fire situations. Firstly, behavior of steel and timber is described in normal and fire situations. A description of wood combustion is proposed to better understand what underlies the temperature dependence of its properties. A focus is made on the mass transfer that occur into timber as it burns. Then, the timber-steel hybridization is addressed through an overview. Afterward, a literature review is made on a specific configuration type, which is assembled by inserting timber beams between the flanges of a hot-rolled “I” profile, while ensuring that this profile is protected from fire by timber. The description of the elastic behavior of studied beams in normal situation is achieved using the gamma method. Bending tests on hybrid beams and their components corroborate this analytical model, but an unexpected composite behavior is observed when steel yielding begins. Thus, a significant strength gain results from the combination of timber and steel. We manage to simulate this behavior by increasing the yield point of the modeled steel compared to the measured value, as well as the tensile strength of timber. Then, fire tests on unloaded specimens are performed. On this occasion, we confirm that correct temperature measurements into timber require orienting thermocouples parallel to isotherms. Many configurations are compared, which allows to understand in detail the effectiveness of the fire protection provided by wood to steel profiles. Mass transfers that occur into timber appear to have a significant effect on temperatures measured on protected steel profiles. The comparison of measured and simulated temperatures allows to highlight the importance of tightness of assembly joints during exposure to fire. Wood combustion and steel temperatures are observed after the end of the fire exposure, and the behavior of hollow configurations is contrasted with that of the timber filled configurations. Finally, fire tests on mechanically loaded beams show that a steel profile protected using 45 mm thick timber components can resist fire for 81 min. Thus, R60 is exceeded with relatively thin protection. Results show that the loading has an impact on steel temperatures, because of an opening of the assembly joints. Numerical simulations show that timber gives fire resistance of the composite beam both thermally and mechanically, by protecting the steel profile, but also by relieving its load. This work shows the effectiveness of steel-timber composite beams, in normal and fire situations, and contributes to the understanding of their behavior. However, proposals for improvement and new challenges are formulated, opening prospects for the study and use of these composite beams
Cremona, Pierre. "Caractérisation expérimentale et numérique des scenarii de feu impliquant un conduit de fumée d'appareils de combustion bois." Thesis, Chasseneuil-du-Poitou, Ecole nationale supérieure de mécanique et d'aérotechnique, 2017. http://www.theses.fr/2017ESMA0023/document.
Full textThe structural evolution of residential buildings due to thermal, environmental regulations and roll out of the Construction Products Regulation generate major challenge for chimney manufacturers, in particular with regard to the safety of residents during a fire. Two fire resistance scenarios are eloquent in European Regulations: the one associated with the development of fire in the room where the chimney is located and the last reported on the development of fire in the chimney itself, by ignition of the deposits. In both cases, the chimney must not be a vector for propagating fire to adjacent rooms and combustible materials. In this context, the present study aims to characterize the main thermal transfers involved in the two scenarios and to better understand the kinetics of formation, decomposition, ignition and combustion of the deposits within the chimney. To do this, an experimental and numerical approach was adopted. The experimental part allows to determine the chemical characteristics (elemental and chemical analyzes) and thermo-physical characteristics (density, conductivity, effusivity and thermal capacity, porosity, calorific value) of 24 residues from real installations or created in laboratory under representative conditions of combustion. These residues are then studied in thermogravimetric analyzers (TGA) and Cone Calorimeters in order to determine the thermal decomposition steps as well as the flammability and combustibility properties, in cases of piloted and auto-ignition. A consequent database of the set of properties has then been generated. A fire-resistant furnace (according to EN 1366-13) allowed the study of the chimney participation in the propagation of fire from one room to another, through the measurement of temperature fields, above the ceiling. The tests allow the acquisition of data essential to the definition of the initial conditions and the limits necessary for the development and the validation of a numerical model developed under Fluent. This model describes heat transfer by conduction, convection and radiation. It makes possible to estimate the temperature level on the outer wall of the chimney above the furnace, which is required in the EI performance declaration tests according to EN 1366-13, regardless of the configuration of the chimney (diameter, materials...). The results obtained correspond to the need for Poujoulat, whose challenge is to have an experimental and numerical tool for the development of fire-resistant chimney and a database relating to deposits in order to advise the habitants
Lahouar, Mohamed Amine. "Tenue au feu des goujons collés dans le bois et dans le béton." Thesis, Paris Est, 2017. http://www.theses.fr/2017PESC1027/document.
Full textPost-installation of rebars is a structural joining technique allowing the connection and the load transfer between two neighboring structural elements using steel rebars and adhesive polymers. Post-installed rebars were initially used in concrete constructions in retrofitting, extension and in repairing structures by adding new concrete sections to existing elements. Over the time, the improvement in mechanical and adhesion properties of polymer adhesives have allowed to enhance the mechanical behavior of post-installed rebars and led to achieve equivalent or even higher mechanical responses than cast-in place rebars at normal operating temperatures. Thus, post-installed rebars have gradually replaced cast-in place rebars in new constructions for some applications by offering advantageous solutions and flexibility allowing meeting the high architectural requirements. However, the mechanical behavior of post-installed rebars is essentially governed by the mechanical properties of polymer resins, which remain highly sensitive to temperature variation. Consequently, the temperature increase of the post-installed rebars presents a potential risk affecting their safety use. Therefore, fire presents a serious hazard that should be considered when designing post-installed rebars. Recently, the technique of post-installed rebars, exclusively used in reinforced concrete structures, has been transferred to wood structures construction, and called "glued-in rods". This technique, initially used in the retrofitting and the reinforcement of historical monuments, is today used in new construction thanks to its good mechanical and seismic behavior in addition to the possibility it offers to make invisible connections. However, glued-in rods face the same problems as post-installed rebars, especially concerning the temperature increase. The aim of this thesis is to study the evolution of the mechanical behavior of these two connection techniques in order to suggest a design method allowing ensuring their safe use in a fire situation. The study is divided into four levels:i- Study of the behavior of chemical anchors at the scale of materials through characterization tests performed on the anchor components, with a particular emphasis on the study of phenomena occurring at high temperature in the polymer resin.ii- Study of the global behavior of chemical anchors by means of pull-out tests performed at high temperature, at constant load and at stabilized temperature, carried out on post-installed rebars in concrete cylinders and on glued-in rods in parallelepipeds of spruce glulam.iii- Study of the mechanical behavior at high temperature of chemical anchors at the scale of the structure through a full-scale fire test carried out on a cantilever concrete slab connected to a concrete wall using eight post-installed rebars. Test results were also used to validate the suggested design method to predict the fire resistance duration of post-installed rebars in a fire situation.iv- Theoretical study on the evolution of the stress distribution along the anchor during a temperature variation, through the development of a non-linear shear-lag model, allowing to obtain the theoretical stress profiles for any thermal distribution, from the experimental input data obtained by pull-out tests