Seismic Performance and Improvements of Stepback Steel Frames

Stepback buildings in mountainous city are highly irregular in elevation. In the current study, the stress and failure characteristics of the typical stepback structure under the action of earthquake are carried out by MPA. Then the parameter's influence of different numbers of stories and ground columns on the seismic performance of the stepback structure is presented. The fundamental factors affecting the seismic performance of stepback structure are studied theoretically and the improvements of different types of stepback structures are put forward. The results indicate, first, that the upper ground columns are the weakest part of the stepback structure and will be the first to be destroyed under the action of earthquake. Then the dropped stories will be destroyed in succession, which is very unfavorable to the seismic resistance of the structure. Second, the proportion of the dropped stories and the upper ground columns directly affects the overall performance of the structure. When the proportion difference of dropped stories and upper ground columns is small, the seismic performance of the structure is poor. Third, the improvements proposed can effectively better the weak parts and improve the seismic performance of the stepback structures.