The Seismic Performance Research Of Bottom Frame Structure Setting Buckling-restrained Braces

The bottom frame structure has the structure characteristic that the lower rigid is far less than upper, so the the overall seismic performance of it is poor.However, this kind of structure are still widespread in township areas, and most of them have not set aseismic walls according to the standard requirements. In addition, the fortification intensity of part of seismic areas 7 degrees increase from 7 to 8 degrees, which makes the seismic performance of this type of bottom frame structure is more worrying.This paper try to improve the seismic performance of bottom frame structure through setting Buckling-Restrained Brace(BRB). In the first, a typical bottom frame structure is taken as the research object, a modeling technology research of the bottom frame structure and BRB is started, and the modeling method of the bottom frame structure in SAP2000 is summarized; According to the result,through taking time history analysis of the bottom frame structure setting BRB before and after under the action of frequent or severe earthquake, the seismic performance of the structure is analyzed. The results show that setting BRB can effectively reduce the seismic response of the bottom frame structure, and the BRB's stiffness contribution to structure is greater than energy dissipation contribution; In addition, the seismic performance research of bottom frame structures setting two different types of BRB including herringbone type and axillary type is conducted, also the mechanical characteristics of them are compared. It is found that compared to the BRB of axillary type, the BRB of herringbone type could reduce the earthquake response of structure in a greater degree, while the BRB of axillary type could protect the nodes; Finally, The comparative research of setting BRB and adding aseismic walls is conducted.The results show that the scheme of adding aseismic walls has a better control effect to the structure displacement, while increasing the acceleration and shearresponse of the structure st the same time, which is the equivalent of increasing the seismic action of overall structure.