Mario Freitas, Mahdi Ben Ftima, Pierre Léger et Najib Bouaanani
Article de revue (2022)
Accès restreint: Personnel autorisé jusqu'au 19 août 2024 Version finale avant publication Conditions d'utilisation: Creative Commons: Attribution-Pas d'utilisation commerciale-Pas de modification (CC BY-NC-ND) Demander document |
Abstract
Shear keys provide interlocking mechanisms along the vertical contraction joints of many concrete gravity dams. The shear key ultimate shear capacity is typically estimated as a function of the friction and cohesion that could be mobilised across a 2D shear plane located at the base of the key when subjected to a normal confinement pressure, P. A two-dimensional response of dam monoliths and shear keys shearing-off at their bases, is assumed. However, evidence of 3D interlocking behaviour between dam monoliths and the possibility of different key failure mechanisms involving interacting axial, P, shear, V, moment, M, and torsion, T, indicates that typical empirical formulations could significantly overestimate the actual shear key capacity under floods and seismic loadings. This paper presents an evaluation of the load–displacement response of shear keys subjected to multiaxial loading via nonlinear finite element analyses. A concrete “Continuous Surface Cap Model” (CSCM), available in the computer program LS-Dyna, is first shown to best capture the experimental shear keys' ultimate and residual shear capacity responses among five constitutive models. The effects of the tensile strength, fracture energy, confinement pressure, friction coefficient, initial opening, and dilation conditions on the load–displacement response of keys are investigated. Failure envelopes considering the key multiaxial shear capacity with confinement pressure, P, moment, M, and torsion, T, are developed. The ratios between moment and shear, M/V, and torsion and shear, T/V, control the failure mechanism. Increasing these ratios significantly reduce the ultimate shear capacity.
Mots clés
Concrete gravity dams; Nonlinear FE analysis; Shear keys; Multi-axial loading; Failure mechanisms; Failure envelope
Sujet(s): |
1100 Génie des structures > 1100 Génie des structures 1100 Génie des structures > 1101 Charges structurales et sécurité 1100 Génie des structures > 1103 Béton : matériaux et structures |
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Département: | Département des génies civil, géologique et des mines |
Organismes subventionnaires: | CRSNG/NSERC |
Numéro de subvention: | RGPIN137122-04 |
URL de PolyPublie: | https://publications.polymtl.ca/10433/ |
Titre de la revue: | Engineering Structures (vol. 269) |
Maison d'édition: | Elsevier |
DOI: | 10.1016/j.engstruct.2022.114766 |
URL officielle: | https://doi.org/10.1016/j.engstruct.2022.114766 |
Date du dépôt: | 22 août 2022 13:20 |
Dernière modification: | 11 avr. 2024 13:33 |
Citer en APA 7: | Freitas, M., Ben Ftima, M., Léger, P., & Bouaanani, N. (2022). Three-dimensional failure envelope of concrete dam shear keys. Engineering Structures, 269, 114766 (16 pages). https://doi.org/10.1016/j.engstruct.2022.114766 |
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