The Study On Seismic Behavior Of Steel Moment Frames-Eccentrically Braced Frames

In earthquake-resistance protection zone, especially in the buildings of high earthquake intensity regions, earthquake's action plays the main role generally. It is important to design reasonable structure to meet the needs of bearing capacity and stiffness under frequently occurred earthquakes and energy-dissipation capacity and ductility under rare, extreme earthquakes. These needs bring high standards for lateral resisting system.In traditional moment-resisting steel frames, the beams yield because of bending and form plastic hinges to dissipate energy. Therefore, they possess a part of hysteretic behavior and good ductility. However, their lateral stiffness is not enough. In order to control the structure's deformation, the sections must be larger than what the strength needs. So this kind of system is very uneconomical when it is used in buildings more than thirty floors. If a centrically braced steel frame is used, structure's stiffness can be met easily. However, when the braces buckle under severe earthquake and are out of function, the frame collapses quickly because it can't support these loads, thus its energy-dissipation capacity and ductility is poor. However, eccentrically braced steel frame hybrids the advantages of the two formers and obtains integrated effects of perfect security, applicability and economy when been used in buildings in seismic zone.A steel moment frames-eccentrically braced frames is analyzed by the software of SAP2000 with response spectrum analysis, elastic-plastic time history analysis and pushover analysis method. Study the seismic behavior of the structure. Compare the differences and the advantages and disadvantages of theses methods, Evaluate the seismic behavior and plastic hinge distribution and the development of the double lateral-loads-resisting system, getting some conclusions and the existing problems, a few of recommendations and suggestions are put forward for practical design.