Bond Studies of NSC Joints Confined with Stirrups, Steel Fibers, or FRP Sheets


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Title: Bond Studies of NSC Joints Confined with Stirrups, Steel Fibers, or FRP Sheets

Author(s): Bilal S. Hamad

Publication: Special Publication

Volume: 296


Appears on pages(s): 1-12

Keywords: Beam-column joints; bond (concrete to reinforcement); fiber reinforced polymers (FRP Reinforced concrete; hooked-bar anchorages; steel fibers; transverse reinforcement

Date: 3/6/2014

The paper presents an overview of the study carried out to compare the results of three research programs conducted on hooked bars anchored in beam-column joints in normal strength concrete (NSC) structures at the American University of Beirut (AUB). The specimen simulated the rigid connection of a cantilever beam to a column. In the first program, the beam-column joint was confined externally with carbon fiber reinforced polymer (CFRP) sheets. Confinement of the joint in the second program was provided internally by steel fibers of varying volume fractions incorporated in the concrete mix. Although stirrups were included in the beam and column elements of the specimens of the first two programs, however the column stirrups were not extended in the beam-column joint. In the third program, confinement of the joint was provided internally by different amounts of stirrups. Test results of the three programs indicated positive effect of the different confining modes on the bond strength of the anchored hooked bars and ductility of the load-deflection history of the tested specimens. The objective of the study reported in the paper is to perform a correlation between the positive effects of the three different confining modes of the beam column joint.