Energy Dissipation Improvement in CBFs Using Perforated Gusset Plates

Concentrically braced frames, CBFs, are the common systems to provide lateral stiffness and strength in buildings that in Comparison with other systems such as moment resisting frames and eccentrically brace frames have less seismic energy dissipation and ductility. This defect caused many studies in the recent years to improve the ductility and seismic performance of them. In this paper, by making hole in the middle or end gusset plates on diagonal and X-braces samples by doing nonlinear static analysis with ABAQUS software, it was tried to provide more ductility and to improve the seismic performance of the brace. This performance is based on the brace buckling prevention. Therefore, holes should be designed in such a way that have less axial capacity than brace critical buckling load to help earthquake energy dissipation. Hysteresis Curves show ductile behavior enhancing energy dissipation during cyclic loading of the final specimens and postponing the occurrence of buckling in the brace members until displacement about 2 cm while normal braces buckled in 1 cm displacement. The reduction of frame stiffness approximately 8-57% and 12-17% increment of equivalent damping prove more ductility and better seismic behavior of the proposed system.