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Materials and Structures

, Volume 35, Issue 6, pp 348–356 | Cite as

Cyclic behavior of HPFRC-repaired reinforced concrete interior beam-column joints

  • M. J. Shannag
  • S. Barakat
  • M. Abdul-Kareem
Technical Reports

Abstract

A large number of old buildings have been identified as having potentially critical detailing to resist earthquakes. The main reinforcement of lap-spliced columns just above the joint region, discontinuous bottom beam reinforcement, and little or no joint transverse reinforcement are the most critical details of interior beam column joints in such buildings. Five 1/3-scale interior beam column joints representing these critical reinforcement details under seismic loads were constructed and tested under cyclic lateral loading simulating seismic excitation. These specimens behaved weakly such that they attained low load carrying capacity, small energy dissipation, and failed in diagonal shear in the joint region. After testing, the specimens were repaired using high performance fiber reinforced concrete (HPFRC) jacket, all around the joint column regions, and retested up to failure. Higher load levels were attained, more ductile behavior was achieved, substantial energy dissipation was observed, slower stiffness degradation was also noted. Failure modes were transformed from brittle shear in the joint diagonals to a ductile one in the beam region through plastic hinge formation in the beam maximum moment sections. Based on the findings of this study, the strengthening technique used promises to provide a cost effective, long-term repair and retrofit solution that can be implemented in the field.

Keywords

Steel Fiber Reference Specimen Joint Region Stiffness Degradation Specimen Number 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Résumé

Un grand nombre de constructions anciennes a été identifié comme ayant partiellement une situation critique vis-à-vis de la résistance aux tremblements de terre. Pour de telles structures, les détails les plus critiques des joints de colonnes de poutres intérieures sont l'armature principale des colonnes assemblées les unes au dessus des autres, directement au dessus de la zone des joints, le renforcement discontinu de la partie inférieure de la poutre, ou encore peu ou pas d'armatures transversales au niveau des joints. Des joints de colonnes de poutres intérieures à échelle 1/3 représentant ces éléments critiques liés au renforcement sous des charges sismiques ont été construits et testés sous un chargement cyclique latéral simulant une excitation sismique. Ces spécimens ont révélé un comportement si faible qu'ils ont atteint une basse capacité de charge porteuse, peu de dissipation d'énergie et qu'ils ont subi une défaillance du cisaillement diagonal dans la zone des joints. À l'issue de l'essai, ces échantillons ont été réparés en utilisant du béton de hautes performances renforcé par des fibres (HPFRC) tout autour de la zone des joints. Puis ils ont à nouveau été testés jusqu'à leur rupture. Des niveaux de charge plus élevés ont été atteints et on a observé un comportement plus ductile et une dissipation substantielle d'énergie, ainsi qu'une dégradation de la ténacité moins rapide. Les modes de rupture sont passés d'un cisaillement fragile au niveau des diagonales des joints à un cisaillement ductile au niveau des sections de poutre au moment maximal. S'appuyant sur les résultats de cette étude, la technique de reforcement utilisée propose une réparation à long terme pour un bon rapport qualité-prix et offre une solution qui peut être appliquée avantageusement sur le terrain.

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Copyright information

© RILEM 2002

Authors and Affiliations

  • M. J. Shannag
    • 1
  • S. Barakat
    • 1
  • M. Abdul-Kareem
    • 1
  1. 1.Department of Civil EngineeringJordan University of Science and TechnologyIrbidJordan

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