The Analysis On Seismic Response Of High-Rise Steel Frame-Brace Structure With Strengthened Story

With the height increase of high-rise buildings, the influence of horizontal actions will become evident and lateral displacement will be large. It is an effective means for decrease of structural horizontal displacement to set up a strengthened story, which has been proved by many experts' researches and engineering practices. In the meantime, the setup of strengthened story will cause sudden change of structural rigidity and internal force and form of a weak layer. Under the action of wind load, high-rise buildings with strengthened story generally will not be damaged becanse sudden change of internal forces is small. We must give more consideration to severe sudden change of structural rigidity and internal forces because of the setting of strengthed story under seismic action.Compared with high-rise reinforced concrete buildings, high-rise steel structures have smaller rigidity and higher weight, and their members are more slender. In order to improve the overall rigidity of the structures, one or more strengthened stories are designed, horizontal strengthened stories have large influence on anti-seismic performance of the structures. As the development of our country's economy as well as improving producing capability in steel materials, more and more steel structures are built in China. In recent years, it is an obvious trend to build high buildings with steel frame-brace structure. At present, strengthened stories are mainly aimed at concrete structures in China, so it is rare that steel frame-brace structure has strengthened story.In the paper, with the finite element software SAP2000, seismic response of the models of high-rise steel frame-brace structures with horizontal strengthened stories are analyzed. Througe the comparasion and analysis of six different schemes of a 32-storied building, the optimal position of horizontal strengthened story has been researched. Meantime, structural cycles of different schemes has been comparized and analyzed, and the strengthened stories' influence on structural lateral displacement as well as member internal forces and horizontal shear forces' distribution of internal tube and external frame under the action of earthquake has been researched.