Expérimentation et modélisation du comportement des assemblages en bois réalisés par des tourillons en bois densifié sous des charges monotones et cycliques

It is a question of working on multi-layered beams (or cross-laminated wood panels assembled mechanically by densified wood dowels) Traditionally, this type of beam, called laminated beam, is obtained by gluing wooden laminates. which ensures a "perfect" connection thus leading to a multi-layer beam (or Panels) whose characteristics can be obtained by homogenization. In this work, it proposed to replace the glue by the densified wood dowels to make the assemblies. The viability of beams (or panels) assembled by densified wood dowels (more ecological) is not yet fully demonstrated and therefore remains exploratory. The analysis of this type of structure (static or dynamic) must consider the fact that the connection between the wood parts is semi-rigid. therefore, it is precisely planned to characterize this type of structure experimentally and on a large scale. The main objective of the proposed thesis is to evaluate the structural response under monotonic and cyclic loads. More particularly, the response under cyclic load is obviously a key parameter for the validation of this type of assembly under seismic load. As part of this study, it is envisaged to use numerical simulation (use of Abaqus) to reduce expensive experimental tests and optimize the chosen design choices.Il s’agit de travailler sur des poutres multicouches (ou panneaux en bois lamellé-croisé assemblées mécaniquement par des tourillons en bois densifié. Traditionnellement, ce type de poutre, appelé poutre en bois lamellé-collé, est obtenu par collage des lamelles en bois, ce qui assure une liaison « parfaite » conduisant ainsi à une poutre (ou plaque) multicouches dont les caractéristiques peuvent être obtenues par homogénéisation. Dans le sujet proposé, il s’agit de remplacer la colle par des liaisons effectuées par des tourillons en bois densifié. La viabilité des poutres (ou panneaux) assemblées par tourillons en bois densifié (plus écologiques) n’est pas encore tout à fait démontrée et reste donc exploratoire. L’analyse de ce type de structures (en statique ou en dynamique) doit prendre en compte le fait que la liaison entre les lamelles est semi-rigide. Donc, il est justement prévu de caractériser expérimentalement et à grande échelle ce type de structures. L’objectif principal de la thèse proposée est d’évaluer la réponse structurelle sous charges monotone et cyclique. Plus particulièrement, la réponse sous charge cyclique est évidement un paramètre clé pour la validation de ce type d’assemblage sous charge sismique. Dans le cadre de cette étude, il est envisagé d’utiliser la simulation numérique (utilisation d’Abaqus) afin de réduire les tests expérimentaux couteux et d’optimiser les choix de conception retenus

Experimental and numerical modelling of the monotonic and cyclic responses of adhesive free laminated structures assembled through compressed wood dowels

Il s’agit de travailler sur des poutres multicouches (ou panneaux en bois lamellé-croisé assemblées mécaniquement par des tourillons en bois densifié. Traditionnellement, ce type de poutre, appelé poutre en bois lamellé-collé, est obtenu par collage des lamelles en bois, ce qui assure une liaison « parfaite » conduisant ainsi à une poutre (ou plaque) multicouches dont les caractéristiques peuvent être obtenues par homogénéisation. Dans le sujet proposé, il s’agit de remplacer la colle par des liaisons effectuées par des tourillons en bois densifié. La viabilité des poutres (ou panneaux) assemblées par tourillons en bois densifié (plus écologiques) n’est pas encore tout à fait démontrée et reste donc exploratoire. L’analyse de ce type de structures (en statique ou en dynamique) doit prendre en compte le fait que la liaison entre les lamelles est semi-rigide. Donc, il est justement prévu de caractériser expérimentalement et à grande échelle ce type de structures. L’objectif principal de la thèse proposée est d’évaluer la réponse structurelle sous charges monotone et cyclique. Plus particulièrement, la réponse sous charge cyclique est évidement un paramètre clé pour la validation de ce type d’assemblage sous charge sismique. Dans le cadre de cette étude, il est envisagé d’utiliser la simulation numérique (utilisation d’Abaqus) afin de réduire les tests expérimentaux couteux et d’optimiser les choix de conception retenus.It is a question of working on multi-layered beams (or cross-laminated wood panels assembled mechanically by densified wood dowels) Traditionally, this type of beam, called laminated beam, is obtained by gluing wooden laminates. which ensures a "perfect" connection thus leading to a multi-layer beam (or Panels) whose characteristics can be obtained by homogenization. In this work, it proposed to replace the glue by the densified wood dowels to make the assemblies. The viability of beams (or panels) assembled by densified wood dowels (more ecological) is not yet fully demonstrated and therefore remains exploratory. The analysis of this type of structure (static or dynamic) must consider the fact that the connection between the wood parts is semi-rigid. therefore, it is precisely planned to characterize this type of structure experimentally and on a large scale. The main objective of the proposed thesis is to evaluate the structural response under monotonic and cyclic loads. More particularly, the response under cyclic load is obviously a key parameter for the validation of this type of assembly under seismic load. As part of this study, it is envisaged to use numerical simulation (use of Abaqus) to reduce expensive experimental tests and optimize the chosen design choices

Review of state of the art dowel laminated timber members and densified wood materials as sustainable engineered wood products for construction and building applications

Engineered Wood Products (EWPs) are increasingly being used as construction and building materials. However, the predominant use of petroleum-based adhesives in EWPs contributes to the release of toxic gases (e.g. Volatile Organic Compounds (VOCs) and formaldehyde) which are harmful to the environment. Also, the use of adhesives in EWPs affects their end-of-life disposal, reusability and recyclability. This paper focusses on dowel laminated timber members and densified wood materials, which are adhesive free and sustainable alternatives to commonly used EWPs (e.g. glulam and CLT). The improved mechanical properties and tight fitting due to spring-back of densified wood support their use as sustainable alternatives to hardwood fasteners to overcome their disadvantages such as loss of stiffness over time and dimensional instability. This approach would also contribute to the uptake of dowel laminated timber members and densified wood materials for more diverse and advanced structural applications and subsequently yield both environmental and economic benefits.The authors wish to record their appreciation to Interreg North-West Europe (NWE) funded by the European Regional Development Fund (ERDF) for supporting the project (Towards Adhesive Free Timber Buildings (AFTB) - 348).peer-reviewe

Review of State of the Art of Dowel Laminated Timber Members and Densified Wood Materials as Sustainable Engineered Wood Products for Construction and Building Applications

Engineered Wood Products (EWPs) are increasingly being used as construction and building materials. However, the predominant use of petroleum-based adhesives in EWPs contributes to the release of toxic gases (e.g. Volatile Organic Compounds (VOCs) and formaldehyde) which are harmful to the environment. Also, the use of adhesives in EWPs affects their end-of-life disposal, reusability and recyclability. This paper focusses on dowel laminated timber members and densified wood materials, which are adhesive free and sustainable alternatives to commonly used EWPs (e.g. glulam and CLT). The improved mechanical properties and tight fitting due to spring-back of densified wood support their use as sustainable alternatives to hardwood fasteners to overcome their disadvantages such as loss of stiffness over time and dimensional instability. This approach would also contribute to the uptake of dowel laminated timber members and densified wood materials for more diverse and advanced structural applications and subsequently yield both environmental and economic benefits.The authors wish to record their appreciation to Interreg North-West Europe (NWE) funded by the European Regional Development Fund (ERDF) for supporting the project (Towards Adhesive Free Timber Buildings (AFTB) - 348).peer-reviewe

Review of state of the art dowel laminated timber members and densified wood materials as sustainable engineered wood products for construction and building applications

Engineered Wood Products (EWPs) are increasingly being used as construction and building materials. However, the predominant use of petroleum-based adhesives in EWPs contributes to the release of toxic gases (e.g. Volatile Organic Compounds (VOCs) and formaldehyde) which are harmful to the environment. Also, the use of adhesives in EWPs affects their end-of-life disposal, reusability and recyclability. This paper focusses on dowel laminated timber members and densified wood materials, which are adhesive free and sustainable alternatives to commonly used EWPs (e.g. glulam and CLT). The improved mechanical properties and tight fitting due to spring-back of densified wood support their use as sustainable alternatives to hardwood fasteners to overcome their disadvantages such as loss of stiffness over time and dimensional instability. This approach would also contribute to the uptake of dowel laminated timber members and densified wood materials for more diverse and advanced structural applications and subsequently yield both environmental and economic benefits.The authors wish to record their appreciation to Interreg North-West Europe (NWE) funded by the European Regional Development Fund (ERDF) for supporting the project (Towards Adhesive Free Timber Buildings (AFTB) - 348)