The Seismic Performance Analysis For The Moment Frame-zipper Frame Dual System

The moment frame-zipper frame dual system belongs to the dual system combining moment frame with braced frame.Now many scholars and experts at home and abroad have done a lot of research about the seismic performance of dual system combining moment frame with braced frame and achieved fruitful results.But there are still many different views about how to choose moment frame design method,and there are some differences in the implementation of the relevant provisions.This paper,on the basis of summarizing the domestic and foreign research,does some research about moment frame design method of the moment frame-zipper frame dual system,details as follows:1)According to the modified suspended zipper frames,this paper designs two kinds of models,in which any story of the moment frames were designed can independently resist 25 percent of the story shear force or 25 percent of the base shear force,and the zipper frames were designed,and then the dynamic responses of the two models are analyzed.The results show that two types of dual systems have similar vibration frequencies and amount of steel,and also show the similar dynamic responses under frequent and rare earthquakes,if no brace fractures.It indicates that the structural system can meet the requirements of the GB50011-2010 code.2)In order to assess the fatigue behavior of braces that were designed by the method proposed in this paper,a low cycle fatigue life estimation method based on the number of cycles of brace was used to compute the fatigue damage of braces under rare earthquakes.Results indicate that the fatigue damage of braces of the two models is quite small under two moment frame design methods.Therefore Low cycle fatigue failure of the brace will not occur.3)Taking into account various adverse effects,it is considered that the brace under rare earthquake will be broken at a certain time.The story of the brace breaks generally will form a weak layer as the same time the sooner the brace breaks,the greater the dynamic response,through the dynamic response analysis of the structure.When one or two braces appear fracture,the dynamic responses is similar.On the whole,the dual system that any story of the moment frame can independently resist 25 percent of the base shear force shows better about seismic performance.In order to ensure the safety performance of the structure,this paper recommends that the seismic design for the moment frame-zipper frame dual system should be performed to ensure that the any story of the moment frame can independently resist 25 percent of the base shear force.