Analyse und Bemessung von Betonbalken mit vorgespannter CFK-Bewehrung
Notice bibliographique
Résumé
Fiber reinforced polymer (FRP) reinforcements combine high strength with low weight and have a high corrosion resistance. Due to these beneficial characteristics, the use of FRP reinforcement in concrete structures has been established and investigated over the last 30 years as a suitable solution for sustainable and long-lasting concrete constructions. In particular, carbon fiber reinforced polymer (CFRP) tendons have a high potential to be applied as prestressing reinforcement due to their higher stiffness and tensile strength as well as better durability compared to reinforcements using glass or aramid fibers. CFRP tendons have been successfully used in many bridge projects in the United States and Canada. Nevertheless, the application of CFRP prestressing tendons in bridge design is not common. The main reasons for the limited implementation of this technology are the lack of standardized material properties as well as consistent and approved design guidelines. To enable a widespread and feasible application of CFRP tendons, comprehensive design methods, comparable to those for steel prestressed concrete structures, are necessary. Furthermore, the design guidelines have to comply with reliability requirements to guarantee the safety of the structures. In the present thesis, the behavior of prestressed concrete beams with CFRP tendons at the ultimate limit state is analyzed in detail. Based on the results, suitable design methods are developed. The transfer of the prestressing force and the tendon anchorage are important design aspects for the construction of pre-tensioned concrete structures. Based on experimental investigations and results from literature, detailing provisions are defined to avoid splitting cracks in the transfer zone and to secure an undisturbed transfer of the prestressing force. Moreover, a theoretical model is derived to determine both the transfer and development length of CFRP tendons depending on their bond characteristics. Using probabilistic calibration, a design model meeting the reliability requirements of Eurocode 0 is proposed. Besides the bond behavior, the flexural strength is a main aspect of the design of beams prestressed with CFRP tendons. Based on the concept of a balanced reinforcement ratio, a flexural resistance model is derived in compliance with Eurocode 2. To develop an appropriate design model, a reliability analysis is performed using stochastic simulations to determine the governing safety factor for the CFRP tendons. For this purpose, two footbridge concepts with prestressed CFRP reinforcement are investigated. To avoid brittle shear failures, the shear strength of reinforced concrete beams has to be verified at ultimate limit state. To extend the database of shear tests on prestressed beams with FRP reinforcement, beams with textile shear reinforcement and prestressed CFRP tendons are tested. Furthermore, theoretical investigations are conducted to derive a shear design model for prestressed and non-prestressed beams with FRP shear reinforcement. For this purpose, a truss model with variable strut inclination is developed. The angle of the compression strut is derived based on a compression field model originally developed for steel reinforced beams.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,001 | 0,001 |
| Méta-épidémiologie (sens strict) | 0,001 | 0,000 |
| Méta-épidémiologie (sens large) | 0,001 | 0,001 |
| Bibliométrie | 0,002 | 0,001 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,001 | 0,001 |
| Science ouverte | 0,000 | 0,001 |
| Intégrité de la recherche | 0,001 | 0,001 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,004 | 0,002 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».