Title:
Performance of Mechanical Couplers of High-Strength Reinforcing Bars under Inelastic Strain Demands
Author(s):
L. K. Sharma, W. Abdullah, S. Niroula, N. Budhathoki, and W. M. Ghannoum
Publication:
Structural Journal
Volume:
122
Issue:
1
Appears on pages(s):
225-238
Keywords:
couplers; fatigue test; Grade 80 (550 MPa); inelastic cyclic tests; mechanical splices
DOI:
10.14359/51743341
Date:
1/1/2025
Abstract:
ACI 318 permits the use of mechanical couplers for Grade 60
(420 MPa) bars in hinge regions, but not for higher-grade bars.
This restriction was introduced due to limited testing of mechanical
couplers under inelastic strain demands and is hindering the use of
higher-grade bars in seismic regions. Eleven mechanical couplers
splicing Grade 80 (550 MPa) bars through varying connection
details were tested in a uniaxial testing machine to evaluate their
performance compared to bare bars under reversed cyclic inelastic
strain demands, akin to those experienced in hinge regions of
special seismic systems. The low-cycle fatigue life of coupled
subassemblies is compared to those of the bare bars tested under
the same loading protocol. Results indicate that some coupled
bars can have equivalent fatigue life to the bare bars, while others
can have substantially reduced fatigue life. A qualification test is
proposed to qualify mechanical splices for use in seismic hinge
regions of special concrete systems.