Seismic behavior of knee bracing frame, buckling-restrained brace, and eccentrically braced frame using nonlinear dynamic analysis
الموضوعات : Computer EngineeringMohammad Hadi Eslami 1 , Mohammad Reza Mostakhdemin Hosseini 2
1 - Former M.Sc. Student, Department of Civil Engineering, Mahdishahr Branch, Islamic Azad University, Mahdishahr, Iran.
2 - Assistant Professor, Department of Civil Engineering, Mahdishahr Branch, Islamic Azad University, Mahdishahr, Iran.
الکلمات المفتاحية: Dynamic analysis, IDA, Energy dissipation and absorption capacity,
ملخص المقالة :
In this study, the seismic performance of three bracing systems including knee bracing frame (KBF), buckling-restrained brace (BRB), and eccentrically braced frame (EBF) for steel moment-resisting structures with varying heights (5, 10, and 15 stories) were investigated using nonlinear time-history analysis and incremental dynamic analysis (IDA). The structural models were first designed in ETABS and analyzed under the influence of different earthquakes, including El Centro, Kobe, and Tabas, using nonlinear time-history analysis. The seismic response and optimal bracing system for each scenario were assessed. To further evaluate of the failure conditions and the ductility capacity of the frames, IDA was conducted in Seismostruct. The results indicated that the 5-story frame with a BRB system, the 10-story and the 15-story with a KBF system exhibited the best seismic performance. The IDA curves revealed that the 5-story BRB-braced structure demonstrated limited ductility and experienced brittle failure, with a large number of failed elements. As the building height increased, the structural ductility improved, particularly in the 10-story frame where the use of KBF significantly enhanced the results. For the 15-story frame, combining high ductility and the KBF system resulted in a highly effective seismic response, as evidenced by smooth IDA curve development, indicating a soft and stable structural behavior. Therefore, the KBF system is proposed as a highly suitable option for high-rise buildings to enhance ductility, energy absorption, and dissipation capacity, and to control the yielding and failure of structural members.
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