Behaviour of an all-steel buckling-restrained brace with restrained web under cyclic loads

The cyclic behaviour of an all-steel buckling-restrained brace (BRB) with a restrained web was investigated. Initially, the BRB’s performance was evaluated and compared with experimental data. After validation, parametric studies were conducted to analyse the effects of the steel core thickness and the friction coefficient between the core and the steel casing. Using non-linear static analysis under cyclic loading based on AISC 341-10, Abaqus was used for modelling. The results showed that increasing the friction coefficient and the core thickness enhanced the brace’s ultimate strength. However, a higher friction coefficient reduced ductility and energy dissipation, leading to buckling at 0.4 friction. Additionally, the BRB system’s impact on a four-storey steel frame was assessed by comparing conventional braces and BRBs. The frame was modelled in OpenSees and subjected to incremental dynamic analysis using 16 earthquake records. The results showed that BRBs led to a uniform distribution of non-linear responses and a higher collapse acceleration, while conventional bracing caused earlier collapse. With an increase in earthquake intensity, the structure initially behaved elastically before entering the non-linear phase. Overall, the BRB system demonstrated improved seismic performance, making it suitable for resisting high-intensity earthquakes.