Seismic Performance Evaluation of Frames Whit Buckling-Restrained Knee Members Using Nonlinear Dynamic Analysis

Steel frames with buckling-resistant knee members are one of the new lateral bearing systems. They are made using short buckling-resistant members at the beam-to-column junctions. Using mentioned members, reduces the architectural limitations and reparability of frames in addition to increasing their seismic performance. Despite the mentioned advantages, these types of frames have not yet been recognized as one of the lateral resistance systems by the 2800 standard. The purpose of this study is to evaluate the seismic performance of this lateral resistant system according to Iranian standards. To achieve this goal, in the first step, 16 steel frames with 3, 6, 9, and 12 stories with different sizes were modeled By Perform 3d. The design of the mentioned frames was done using the performance-based plastic design method. In the next step, non-linear dynamic analysis method was used for seismic evaluation of the structure. In the next step, the nonlinear dynamic analysis method was used for the seismic performance assessment of buckling-restrained knee brace frames. For this purpose, 8 earthquake records were selected and scaled according to the 2800 standard method. After the frames analysis, a seismic evaluation was performed according to Instruction for Seismic Rehabilitation of Existing Buildings (code No. 360). The results of this research showed that the performance level of life safety in buckling-restrained knee-braced frames as a malleable ring of a structural system is provided in terms of building performance levels according to the definition provided in 360 publication.