| Title |
Confinement Effects on the Bond Properties of Reinforcement with Improved Rib-Shape |
| Keywords |
Confinement Effect ; Relative Rib Area ; Rib Shape ; Bond Strength ; Development Length |
| Abstract |
High strength reinforcements were recently developed as the needs for high strength structural materials in building structure arose, and these were caused the increase of concerns about the bond properties of reinforcement. This paper reports the works about the beam splice tests which test variables were rib shape, confinement by the stirrups and concrete compressive strength. Total 8 simple beam type specimens which had the lap splice in the middle span zone were tested, and each specimen designed to occur the bond failure in the splice area of the beam before the tensile reinforcements yielded. Test data was analyzed to define the influence of the 3 variables in the viewpoint of bond strength, and compared with present local design code requirements and existing research results. Test results indicated that high relative rib area and the improvement of rib shape can increase the bond strength, and the confinement effect by placing the stirrups can increase the bond strength up to 8～36%. Local structural design code requirements for development and splice length of the reinforcement excessively underestimate the bond strength, and the proposed equation of ACI 408 committee rather agreed with the test results. |