Cyclic behavior of precast high-strength reinforced concrete columns

Double-curvature cyclic tests of large-scale columns were conducted to investigate the seismic performance of precast highstrength reinforced concrete (RC) columns. High-strength concrete and high-strength longitudinal and transverse reinforcement were used. The use of grouted coupler splices for the high-strength longitudinal reinforcement in the plastic hinge zone and the use of butt-welded splices for the high-strength transverse reinforcement were examined. Test results showed that precast columns with the grouted coupler splices exhibited comparable seismic performance with monolithic counterparts. The butt-welded splice had a negligible effect on the tensile behavior of the spliced bars. However, precast columns with such welded splices in transverse reinforcement showed smaller ultimate drift capacities than their counterparts with hooked transverse reinforcement. This was due to the reduced resistance of butt-welded transverse reinforcement to buckling of longitudinal reinforcement. Shear, flexural, and confinement design equations for the precast high-strength columns were discussed by comparing with the test results.