Évaluation du comportement en vibration et optimisation de la conception des planchers composite en bois lamellé collé croisé-béton
Bibliographic record
Abstract
Ce projet de recherche vise l’évaluation du comportement en vibration et l’optimisation de la conception des planchers composite en bois lamellé collé croisé-béton. La connexion est réalisée par entaille dans le CLT renforcée par deux vis. Cette connexion n’est pas sous avis technique. Néanmoins, elle reste donc accessible économiquement, ne nécessite qu’un usinage simple et limite l’intervention sur site. Elle vise à réaliser des planchers de grandes portées nécessaires, particulièrement au Québec et en France, pour la réalisation de bâtiments multiétages en bois dont le marché est en plein développement et en demande de solutions planchers peu ou pas carbonées, de hauteur statique réduite satisfaisant aux contraintes normatives dont la plus exigeante est la vibration. D’abord, le comportement d’un connecteur composite individuel a été étudié. Le connecteur à l’entaille renforcée par vis a été testé en cisaillement statique. Un modèle par des éléments finis a été proposé permettant de décrire la rigidité statique et la résistance en cisaillement du connecteur de différente configuration. Ensuite, trois poutres en bois lamellé collé croisé-béton de longue portée (9 mètres) avec différentes densités de connecteurs, ont été soumises à des essais de vibration et de flexion statique. Des expressions analytiques, dont une est proposée par la norme Eurocode 5, ainsi qu’un modèle simplifié par éléments finis ont donné de bonnes estimations des fréquences naturelles mesurées. Pourtant, une calibration des modules des panneaux en bois lamellé collé croisé due à l’impact des entailles a été nécessaire. Enfin, une optimisation multi-objectif des planchers en bois lamellé collé croisé-béton a été effectuée. Elle a pris comme objectifs à minimiser le poids, la hauteur statique du plancher et le coût total en restant soumis aux contraintes de l’état limite de service (flèche et vibration) et de l’état limite ultime (flexion et cisaillement). Un front de Pareto des solutions optimisées a été obtenu. La configuration testée est une solution d’ingénierie conventionnelle qui ne figure pas sur ce front de Pareto. L’outil d’optimisation se révèle donc potentiellement pertinent susceptible d’aider les ingénieurs à définir leurs conceptions. \n \nThis research project aims to evaluate the vibration behavior and optimize the design of cross-laminated timber-concrete composite floors. These floor structures are a composite made of a cross-laminated timber panel and a concrete layer. They are connected by a notch carved into the cross-laminated timber and reinforced by two vertical screws. This connection is an innovative solution and still needs further regulation by a technical notice. Nonetheless, it remains economically accessible, requires only simple machining, and limits on-site intervention. The composite floor will have a large span necessary, particularly in Quebec and France, to construct multi-story timber buildings whose market is in total development. Such floor systems will satisfy the demand for low or no carbon footprint floor solutions for reducing the static height while complying with the normative constraints of which the most demanding is the vibration. First, the behavior of a single composite notch connector was studied. The chosen connector, screw reinforced notched, has been tested in static shear. Furthermore, a finite element model has been proposed to describe the static stiffness and the shear strength of the connector of different configurations. Then, three long-span (9 meters) cross-laminated timber-concrete beams with different connector densities were subjected to vibration and static bending tests. Analytical expressions proposed by Eurocode 5 and a simplified finite element model gave reasonable estimates of the measured natural frequencies. However, the module calibration of the cross-laminated timber panels due to the impact of the notches was necessary. Finally, multi-objective optimization of cross-laminated timber-concrete floors was carried out. Its objectives were to minimize the weight, the static height of the floor, and the total cost while complying with the constraints of the serviceability limit state (deflection and vibration) and the ultimate limit state (bending and shearing). A Pareto front of optimized solutions was obtained. The configuration tested is a conventional engineering solution that does not appear on this Pareto front. The optimization tool is, therefore, potentially relevant and can help engineers define their designs.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.008 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".