Design method of buckling-restrained brace frame based on energy balance

A design method for buckling restrained brace frames(BRBFs) was proposed based on energy concept.The input seismic energy was assumed to be dissipated by the steel frame and BRBs at the target displacement.On the basis of the input energy of the frame without BRBs,the input energy of BRBFs was obtained by adjusting its structural period and ductility.The energy dissipated in one cycle at the positive and negative maximum displacements was taken as the total dissipated energy under an earthquake.The required energy dissipation curve and the energy dissipation curve at the target displacement were established to obtain the area of the section of the BRB.A three-bay and five-story BRBF was designed based on the proposed method.And a finite element model was established using ANSYS.The results of the nonlinear time history analysis for the structure indicate the maximum inter-story drift agrees well with the target value,and the designed structure is safe.