Pullout Test of Headed Reinforcement

Headed Reinforcement 인발실험

Objectives of this study included design of head and evaluation of the pullout performance of the headed reinforcement that can be used to replace standard hooks in the building exterior beam-column joints. Results of 36 pullout tests are presented. Test variables included reinforcing bar diameters (16-25mm), embedment depth (6-7db), transverse reinforcement, and single-vs.-group pullout behavior. The square head designed had gross area of 4Ab and thickness of db. The headed reinforcement made of Dl6 bars developed pullout strengths close to the bar yield strength, but larger bars developed strengths smaller than the yield strengths. The pullout resistance increased with decreasing spacing of the transverse reinforcement. Use of column ties with 6.0-db spacing improved the pullout performance of the headed bars without causing difficulties in fabricating the specimens. The comparison of the pullout performances between the headed bars and the standard hooks revealed that strengths, stiffnesses, and ductile behaviors are about the same.