| Title |
Evaluation of Hysteretic Behaviors of the Buckling Restrained Braces according to the Unconstrained Length |
| Authors |
Park Dae-Jin ; Ju Young-Kyu ; Kim Myeong-Han ; Kim Do-Hyun ; Kim Sang-Dae |
| Keywords |
Buckling Restrained Brace ; Core ; Unconstrained Length ; Strength-Stiffness of Tube ; Finite Element Analysis |
| Abstract |
This study proposes a numerical analysis model whose behavior was analytically repeatable in an actual BRBs. Moreover, the result of the FEA was compared with the result of the existing component capacity test. In addition, six models were proposed, whose unconstrained area varied in length. The unconstrained area whose length proved most efficient was proposed using the verified analytical method to analyze the core's performance, depending on the unconstrained length, among various parameters that influence the strength of the BRB. According to the result of the analysis, the performance of the core increased as the ratio of the unconstrained length to the total length of the BRB decreased, and dropped rapidly at 28% or greater. When this result was compared with the strength-stiffness relation of the steel tube of existing studies, it was shown that the section performance of the steel tube increased the longer the unconstrained length was at both ends of the core. Moreover, the initial geometrical deformation increased as the stiffness of the core increased. However, the failure mode depends on the core's unconstrained length yielding caused by axial force and resultant additional bending moment, requiring the installation of more reinforcing plates to prevent failure, which makes the whole structure uneconomical. Therefore, the best performing BRB will be one whose unconstrained length is 16～24%, in consideration of the constructability due to field connection. |