Design Method of Diamond Buckling Restrained Braced Frame Structure Based on Normal Force Balance of Column Joints

The diamond buckling restrained braced frame (DBRBF) structure is a novel form of an anti--lateral force support system.A design method for DBRBF structures suitable for various structural types is proposed based on the equilibrium of normal forces in column joints.Taking into account the impact of linear stiffness ratio between upper and lower buckling restrained braced (BRB) elements on the unbalanced forces in column joints of DBRBF sructures, a design method is presented to ensure the normal force balance before and after BRB yield.Building upon this, the calculation method for determining the optimal linear stiffness ratio of two types of BRB elements and the corresponding design method are provided along with the deduced matching conditions for the two types of BRB designs.Furthermore, the relationship between the energy dissipation capacity of BRB elements and deformation of the primary structure under different seismic levels is examined, establishing the condition under which BRB elements serve as the first line of defense prior to yielding of the primary structure.Additionally, the conditions for energy dissipation and ductility guarantee of BRB elements under rare earthquakes are specified.An equation is derived for the length of the working section of BRB elements in DBRBF structures.The results demonstrate that the DBRBF structure can effectively mitigate the adverse effects of BRB elements on the columns through a well-designed approach, enabling realization of matched product designs, and providing a theoretical reference for similar engineering design projects.