Experimental Behavior and FE Modeling of Buckling Restrained Braced Frame with Slip-Critical Connection

This paper examines the hysteretic behavior of the buckling restrained braces (BRBs) in the steel frame. Both experimental and finite element (FE) studies were conducted. The experimental results showed that the well-detailed buckling restrained braced frame (BRBF) withstood significant drift demands, while the BRB exhibited significant yield without severe damage. Although the BRB inside the steel frame was subjected to 2.69% strain of the CP under the axial compression demands, the local and global deformations were not observed. The FE model was developed and validated. The numerical investigations of hysteretic behavior of the BRBF in the literature are generally focused on the friction between the core plate (CP) and the casing member (CM). The results suggest that the behavior of the BRBF is significantly affected not only by the friction between CP and CM but also by the pretension load on the bolts and the friction between the contact surfaces of steel plates of slip-critical connections in the steel frame. The FE analysis showed that pretension loads of 35 kN and 75 kN gave accurate predictions for cyclic responses of BRBF under tension and compression demands, respectively. Moreover, the FE predictions were in good agreement with the test results when the friction coefficient is 0.05 between CP and CM and it is 0.20 between steel plates.