Study On Seismic Behavior And Design Method Of All-steel Buckling-restrained Brace With Perforated Cruciform Section

In this paper, we used ABAQUS finite element software to simulate the all-steel buckling-restrained brace with perforated cruciform section by summing up the methods from domestic and foreign data related to buckling-restrained braces. Analyzed and compared the effects of different parameters on the brace’s hysteretic energy dissipation capacity. Combined with the finite element analysis results and the theoretical derivation, the design method of the all-steel buckling-restrained brace with perforated cruciform section and the corresponding design example were presented. Finally, I studied the finite element of three single-span steel frame of the all-steel buckling-restrained brace with perforated cruciform section, and analyzed its seismic performance under unidirectional,reciprocating and dynamic load.The influence of parameters, such as different perforation form, number of perforation rows, perforation width, perforation length, the proportion of width and thickness, the constraint proportions and gap, on the brace seismic performance were analyzed. The results showed that the all-steel buckling-restrained brace with perforated cruciform section demonstrated stable hysteretic behavior and good energy dissipation capacity, while yielding was confined in the pre-set area. The stress state of the brace’s end has improved. The yield force of the all-steel buckling-restrained brace with perforated cruciform section can be adjusted by changing perforation width. With the increasing of the perforation length, the elastic-plastic and plastic stiffness of the brace can be decreased. The load-bearing capacity of the brace with double perforation is higher than those with single perforation. The all-steel buckling-restrained brace with perforated cruciform section has good comprehensive performance when the core width thickness ratio is between 5 to 10. The low constraint ratio can not guarantee the stability of the brace under the target displacement, so we suggest that the constraint ratio is greater than 1.92. In ensuring that the gap needed by the lateral deformation of the core can be provided, the smaller the gap size is, the better it is, which is recommended about 1mm.The seismic performance of the all-steel buckling-restrained brace with perforated cruciform section fixed on three storey and single span steel frame is studied. The results showed that the perforated core of the all-steel buckling-restrained brace with perforated cruciform section weakens its brace yield force and makes the frame enter into a state of yielding energy dissipation, but the brace’s bearing capacity has almost no decline. The perforated core is equivalent to strengthen other parts of the frame indirectly. The perforated core effectively reduces the stress of the area of the brace end and the frame beam-column joint and improves the stress condition of the frame’s weak part. The all-steel buckling-restrained brace with perforated cruciform section fixed on three storey and single span steel frame also played a good energy dissipation behavior under dynamic load.