Performance of Mechanical Couplers of High-Strength Reinforcing Bars under Inelastic Strain Demands

(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 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.