The Research On The Seismic Behavior Of Steel Frame-brace Structure With L-shaped Flat

Both the rapid development of economy and precious urban land, more and more high-rise and super high-rise buildings are established. Steel structures have been widely used due to its lightweight, high strength, environmental protection and other features. Steel structure supports metallurgy, construction, manufacturing, machinery and other industries for modern industrialized countries, research has an important significance on the steel structure system in the construction industry and national industry. Steel braced frame structure is a double resistance to lateral force system,which has a good ability to resist lateral displacement and excellent seismic performance.It has been widely used in the construction industry.Irregular structure is easy to occur lateral-torsional coupling effect during an earthquake. Compared with regular structure it is easier to damage. It introduced the theory of seismic analysis and the determination of irregular structure firstly. It described modal analysis theory, static analysis theory, response spectrum theory and time history analysis theory in the seismic analysis of irregular plane in detail.It established four kinds of finite element model for steel braced frame structure with L-shaped flat. They were CBFs,OBFs1,EBFs and OBFs2.Through the modal analysis it got the period, frequency, mass participation factor and analyzed the natural vibration characteristics and torsional characteristics. Through the response spectrum analysis it obtained floor displacement,story drift and story drift angle of the vertical and horizontal direction in different direction and combination of different horizontal directions. It illustrated the different lateral stiffness of the structure and the position of weak story. Through time history analysis it obtained the time history curve of base force and bending moment in EL-Centro wave, Taft wave and artificial wave. Through comparative analysis it found that eccentrically braced structures had the effect of energy dissipation.Based on structural pushover analysis for four structures it got the curve of capacity spectrum and demand spectrum under uniform load distribution and inverted-triangular load distribution.It obtained the performance point for their antiseismic performance analysis. Compared with plastic hinge under frequent earthquake and rare earthquake it found the first appearance of plastic hinges was at the support. Finally,compared maximum floor displacement of Pushover analysis withtime history it can get floor displacement in the Pushover analysis is larger.