Investigating modeling approaches of buckling-restrained braces under cyclic loads

The Main purpose of this paper is to present a practical method for accurate modeling and provide a simple model of buckling restrained braces (BRBs). The components of a BRB were introduced. Furthermore, two complete experimental specimens of BRBs were modeled using the ABAQUS finite element method program. The validity of these models was confirmed after comparing the results of nonlinear dynamic analysis with the experimental specimen results. An intended simple model such as steel core and springs was proposed. It was evaluated and analyzed after modeling, then a method was presented to find the spring stiffness. In this study, a comparison was made between the experimental and analytical hysteresis curves (the complete model and the simplified model) and a good agreement was observed between the two results with 5% difference. Moreover, the two-story moment frame with a BRB in both the complete details and simple states was modeled to verify the simple method of core-spring. The results showed a high accuracy of the simple model of core-spring. In addition, the use of the simplified spring-core model may significantly reduce the time of the analysis compared to the complete model.